IS 14697 : 1999(Reaffirmed 2004)

Edition 1.3(2004-12)

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Indian Standard

ac STATIC TRANSFORMER OPERATEDWATTHOURANDVAR-HOURMETERS, CLASS

0.2 S, 0.5 SAND 1.0 S - SPECIFICATION(Incorporating Amendment Nos. 1, 2 & 3)

Ies 91.140.50

© BIS 2005

BUREAU OF INDIAN STANDARDSMANAK BHAVAN, 9 BAHADUR SHAH ZAFAR MARG

NEW DELHI 110002

Price Group 10

Equipment for Electrical Energy Measurement and Load Control Sectional Committee, ETD 13

FOREWORD

This Indian Standard was adopted hy the Bureau ofIndian Standards, after the draft finalized hythe Equipment for Electrical Energy Measurement and Load Control Sectional Committee hadheen approved hy the Electrotechnical Division Council.

Static electrical watthour meters permit the highest attainable accuracy of energy measurementsand are employed for the accurate measurement of large amount of energy.

The hest possible accuracy is achieved by the class 0.2 S hut electronic techniques available alsoallow smaller errors and deviations under influence quantities for class 0.5 Sand 1.0 S metersthan which are permitted for induction meters of same accuracy classes.

The Indian Standard IS 13779 : 1993 'ac static watthour metric, class 1 and 2 - Specification' wasadopted to cover general requirements and tests for various types of static watt hour meters ofclass 1 and 2, generally in line with the requirements for induction meters. However, this standardspecifies the general requirements and tests applicahle to transformer operated static watthourand Var-hour meters of class 0.2 S, 0.5 Sand 1.0 S keeping in view of performance levelsattainable in such meters.

The letter'S' denotes special measuring range designated for transformer operated applications,generally for large power measurements. Current transformers also'S' designated as per IS 2705(Part 2) : 1992 'Current transformers: Part 2 Measuring current transformers ( second revision)'have measuring ranges comparable to those of static meters covered by this standard. For the sakeof overall accuracy throughout the measuring range, static meters covered hy this standard shouldpreferahly be connected with'S' designated current transformers. For applications seeIS 11448: 2000 'Application guide for ac electricity meters'.

The test levels as specified in this standard are regarded as minimum values to guarantee theproper function of the meter under normal working conditions. For special applications other testlevels might he necessary and have to be fixed between the user and the manufacturer. For testsand test criteria existing tests and test levels have heen taken from IS 13010 : 2002 'ac watthourmeters class 0.5, 1 and 2 - Specification (first revision)' and IS 13779 : 1999. New tests havebeen added in respect of electromagnetic compatibility (EMC) and interference (EMI) for whichrelevant part and section oflEC 61000 series may he referred. The following IEC publication havealso been referred in this standard:

i) IEC 60068-2-75 (1997) Environmental testing - Part 2-75 : Tests - Test Eh : Hammer tests

ii) ISO 75-1 (1993) Determination of temperature of deflection under load - Part 1 : Generaltest method

iii) ISO 75-2 (1993) Determination of temperature of deflection under load - Part 2 : Plasticsand ehonite

The reliability of static meters depends on their electronic components and interconnections and isalways in the process of up gradation. This aspect is not covered in this standard as there are noshort time test procedures available which would fit in the type test document to substantiallycheck this requirement. Also, influence of various harmonics and suitable test procedures todetermine such influences, require detailed consideration for specifying such requirement.While preparing this standard assistance has been mainly derived from the following publications:

IEC 60687 (1992-06) 'Alternating current static watthour meters for active energy (class 0.2 Sand 0.5 S)', issued by the International Electrical Commission.

( Continued on third cover)

IS 14697 : 1999

Indian Standard

ac STATIC TRANSFORMER OPERATEDWATTHOURANDVAR-HOURMETERS, CLASS

0.2 S, 0.5 SAND 1.0 S - SPECIFICATION1 SCOPE

1.1 This standard specifies static watthourmeters of accuracy class 0.2 S, 0.5 Sand 1.0 Sfor the measurement of alternating-currentelectrical active energy of frequency in therange of 45 Hz to 55 Hz for single phase andthree phase balanced and unbalanced loads. Itapplies to their type tests, routine tests andacceptance tests.

1.2 It applies only to transformer operatedstatic watthour meters consisting of measuringelement(s) and register(s) enclosed together inthe meter case. It also applies to operationindicator(s) and test output(s). It also applies tomultirate tariff meters and meters whichmeasure energy in both directions.

1.3 Some versions of static reactive energy(Val"hour) meters may deemed to be covered bythis standard as if these are active energy(Watthour) meters of appropriate accuracyclass with necessary adjustment to powerfactor. Although it is possible to achieve class0.2 S accuracy in static Var-hour meters, it is ofgeneral opinion that accuracy attainable forVar-hour measurement is one level inferior tothat in the case of kWh measurement withidentical design of measuring elements.Therefore, it is possible for this standard tocover static Var-hour meter, class 0.2 S, 0.5 Sand 1.0 S for reactive energy measurement inall transformer operated applications. Only'power factor' wherever it has appeared in thisstandard, shall be read as 'sin <I> inductive' or'sin <I> capacitive' where <I> is respectively thelagging or the leading power factor angle.

1.4 It does not apply to ;

a) Watthour and Var-hour meters, wherethe voltage across the connection terminalexceeds 600 V (line to line voltage fol'meters for polyphase systems);

b) Portable meters and outdoor meters;

c) Data interfaces to the register of themeters.

1.5 For rack-mounted meters, the mechanicalproperties are not covered in this standard.

1

2 REFERENCES

The Indian Standards listed in Annex A arenecessary adjuncts to this standard.

3 TERMINOLOGY

3.1 For the purpose of this standard, thefollowing definitions shall apply.

3.1.1 General

3.1.2 Walthour Meter (Active Energy Meter)

An instrument which measures and registersactive energy in watthours or in suitablemultiples thereof, by integrating active powerwith respect to time.

3.1.3 Static Watt hour Meter

A watthour meter in which current and voltageact on solid state (electronic) elements toproduce an output proportional to watthours.

3.1.4 Reactive Power ( Val' )

Reactive power for sinusoidal waveforms of anysingle frequency in a single phase circuit isdefined as the product of the Lm.S. values ofcurrent and voltage and the sine of the phaseangle between them.

NOTE - For practical reason this standard applies tothe reactive power for sinusoidal current and voltagecontaining the fundamental frequency only.

3.1.5 Reactive Energy ( Val"hour )

3.1.5.1 Reactive energy in a single phase circuit

The value of the reactive power as definedunder 3.1.4 integrated with respect to time.

3.1.5.2 Reactive energy in a polyphase circuit

The algebraic sum of the reactive energies ofthe phases.

NOTE - As this standard is based on reactive energyderived [rom the sinusoidal current and voltage offundamental frequencies. the inductive or capacitivestate of a circuit in this recommendation is given by thefactor 'sin $'.

3.1.6 Var-hour Meter

An instrument which measures and registersreactive energy in Var-hours or in suitablemultiples there of, by integrating reactivepower with respect to time.

IS 14697 : 1999

3.1.7 Static Var-hour Meter

A Var·hour meter in which current and voltageact on solid state (electronic) elements toproduce an output proportional to Var-hours.

3.1.8 Direction and Sign of Reactive Power (seeAnnex F)

3.1.9 Multi-Rate Meter

whenever addressed.

3.2.4 Non Volatile Memory (NVM)

A memory which can retain stored informationin the absence of power.

NOTE - Memory chip with internal battery needing noreplacement during the life time of meter may beconsidered as non volatile memory, but memory withexternal battery shall not be considered as NVM.

An energy meter provided with a number ofregisters, each operative at specified timeintervals corresponding to different tariffs.

a) Similar metrological properties;

b) The same principle of operation anduniform construction of parts determiningthese properties; and

c) The same ratio of the rated maximumcurrent to the basic current.

3.1.10 Meter Type

Designation used for defining adesign of meter manufacturedmanufacturer, having:

particularby one

3.2.5 Display

A device which visibly displays the contents of(a) memory(ies).

3.2.6 Register

A device comprising both memory and displaywhich stores and displays information. A singledisplay may be used with multiple electronicmemories to form multiple registers.

3.2.7 Current Circuit

The internal connections of the meter and partof the measuring element through which flowsthe current of the circuit to which the meter isconnected.

The type may have several values of basiccurrent and several values of reference voltage.

These meters are designated by themanufacturer by one or more groups of lettersor numbers Or a combination of letters andnumbers. Each type has one designation only.

NOTE - The type is represented by the samplemeter(s) intended for the type tests and whosecharacteristics (basic current and reference voltage) arechosen from the values proposed by the manufacturer.

3.2 Terms Related to Functional Elements

3.2.1 Measuring Element

Part of the meter which produces an outputproportional to the energy.

3.2.2 Output Devices

3.2.2.1 Test output

A device at which output from the measuringelement is available for testing of the meter.The output may be in the form of the pulses orhigh resolution register.

3.2.2.2 Operation indicator

A device which gives a visible signal of theoperation of the meter. The test output mayalso act as operation indicator.

3.2.3 Memory

An element which stores digital information ina structured manner for subsequent retrieval

2

3.2.8 Voltage Circuit

The internal connections of the meter, part ofthe measuring element and power supply to themeter, supplied from the voltage of the circuitto which the meter is connected.

3.2.9 Auxiliary Circuit

The elements (lamps, contacts, etc) andconnections of an auxiliary device within themeter case intended to be connected to anexternal device, for example, clock, relay,impulse counter.

3.2.10 Meter Constant

Constant expressing the relation between theenergy registered by the meter and thecorresponding pulse count of the test output.This is generally expressed either as pulsecount per Watthour or pulse count per kiloWatthour (imp/kWh) or Watthour per pulse(Wh/imp). This definition is not applicable formeters having high resolution registers.

For reactive energy, Watthour (Wh) shall beread as Var-hour (Varh).

3.3 Terms Related to Mechanical Elements

3.3.1 Indoo,· Meter

A meter which can only be used in areaswhich have additional protection againstenvironmental influences (inhouse, enclosuresand cabinets).

3.3.2 Outdoor Meter

A meter which can be used without additionalprotection in an exposed outdoor environment.

3.3.3 Meter Base

The back of the meter by which it is generallyftxed and to which are attached the measuringelement, the terminals or the terminal block,and the covel'. For a flush-mounted meter, themeter base may include the sides of the case.

3.3.4 Meter Cover

The enclosure on the front of the meter, madeeither wholly of transparent material or opaquematerial provided with windows(s) throughwhich the operation indicator (if fitted) and thedisplay can be read.

3.3.5 Meter Case

This comprises the base and the cover.

3.3.6 Accessible Conducting Part

A conducting part which can be touched by thestandard test finger, when the meter isinstalled ready for use (see IS 1401 ).

3.3.7 Protective Earth Terminal

The terminal connected to accessible conductingparts of a meter, for safety purposes.

3.3.8 Terminal Block

A support made of insulating material on whichall or some of the terminals of the meter aregrouped together.

3.3.9 Terminal Cover

A covel' which covers the meter terminals andgenerally the ends of the external wires orcables connected to the terminals.

3.3.10 Clearance

The shortest distance measured in air betweentwo conductive parts.

3.3.11 Creepage Distance

The shortest distance measured over thesurface of insulation between two conductiveparts.

3.4 Terms Related to Insulation

3.4.1 Basic Insulation

The insulation applied to live parts to providebasic protection against electric shock.

NOTE - Basic insulation does not necessarily includeinsulation used exclusively for functional purposes.

3.4.2 Supplementary Insulation

An independent insulation applied in additionto the basic insulation, in order to provide

3

IS 14697 : 1999

protection against electric shock in the event ofa failure of the basic insulation.

3.4.3 Double Insulation

An insulation comprising both, basic insulationand supplementary insulation.

3.4.4 Reinforced Insulation

A single insulation system applied to live parts,which provides a degree of protection againstelectric shock equivalent to double insulation.

NOTE - The term 'insulation system' does not implythat the insulation must be one homogenous piece. Itmay comprise several layers which can not be testedsingly as supplementary or basic insulation.

3.4.5 Insulating Encased Meter

A meter with case of insulating material inwhich protection against electric shock does notrely on basic insulation only, but in whichadditional safety precautions, such as doubleinsulation or reinforced insulation, areprovided. There being no provision forprotective earthing or reliance uponinstallation conditions.

3.5 Terms Related to Meter Quantities

3.5.1 Basic Current ( Ib )

The value of current in accordance with whichthe relevant performance of the meter is fixed.

3.5.2 Rated Maximum Current (IM • x )

The highest value of current at which the meterpurports to meet the accuracy requirements ofthis standard, when this current passescontinuously in the meter.

3.5.3 Reference Voltage

The value of voltage in accordance with whichthe relevant performance of the meter is fixed.

3.5.4 Reference Frequency

The value of frequency is accordance withwhich the relevant performance of the meter isftxed.

3.5.5 Class Index

A number which gives the limits of thepermissible percentage error, for all values ofcurrent between 0.05 I b and I M• x for unitypower factor (and in the case of polyphasemeters with balanced loads) when the meter istested under reference conditions (includingpermitted tolerances on the reference values)as defined in this standard.

IS 14697 : 1999

3.5.6 Percentage Erl'Or

The percentage error is given by the followingformula:

NOTES

1 Energy means Active energy (kWh) for Watthourmeter and Reactive energy (kVarh) for Var-hour meter.

2 True value for reactive energy is determined atfundamental frequency.

3 Since the true value cannot be determined, it isapproximated by a value with a stated uncertainty thatcan he traced to national standards or standards agreedupon between manufacturer and user.

3.5.7 Repeatability of EnwRepeatability of error is the degree of closenessof agreement between results of successiveerror tests carried out under identicalconditions, arising out of factors other thanmeasurement uncertainties.

It is generally measured by standard deviationof sufficiently large number of test data. It mayalso be measured by dispersion of such dataunder limited condition when sufficiently largedata is not available.

3.6 Terms Related to Influence Quantities

3.6.1 Influence Quantity or Influence FactorAny quantity, generally external to the meter,which may affect its working performance.

3.6.2 Reference ConditionsThe appropriate set of influence quantities andperformance characteristics with referencevalues, their tolerances and reference ranges,with respect to which the intrinsic error isspecified.

3.6.3 Variation of Error Due to an InfluenceQuantity

The difference between the percentage error ofthe meter when only one influence quantityassumes successively two specified values, oneof them being the reference value.

3.6.4 Distortion Fa.ctorThe ratio of the r.m.S. value of the harmoniccontent (obtained by subtracting from a non·sinusoidal alternating quantity, its fundamentalcomponent) to the r.m.S. value of the non·sinusoidal quantity. The distortion factor isusually expressed in percentage.

3.6.5 Electromagnetic DisturbanceConducted or radiated electromagnetic effectswhich may interfere functionally ormetrologically with the operation of the meter.

3.6.6 Reference TemperatureThe ambient temperature specified for referenceconditions.

Percentageerrol' =

(Energy registered by themeter) - (True energy)

True energyx 100

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3.6.6.1 Mean te/nperature coef[icielLt

The ratio of the variation of the percentageerror to the change of temperature whichproduces this variation, specified normally atthe reference temperature.

3.6.7 Operating Conditions

A set of specified measuring ranges forperformance characteristics and specifiedoperating ranges for influence quantities,within which the variations in percentageerrors of a meter are specified and determined.

3.6.8 Specified Measuring Range

The set of values of a measured quantity forwhich the percentage errors of a meter isintended to lie within specified limits.

3.6.9 Specified Operating Range

A range of values of a single influence quantitywhich forms a part of the operating conditions.

3.6.10 Limit Range of Operation (LimitingConditions)

The extreme conditions which an operatingmeter can withstand without damage andwithout degradation of its metrologicalcharacteristics when it is subsequentlyoperated under its operating conditions.

3.6.11 Storage and Transport Conditions

The extreme conditions which a non-operatingmeter can withstand without damage andwithout degradation of its metrologicalcharacteristics when it is subsequently operatedunder its operating conditions.

3.6.12 Normal Working Position

The position of the meter defined by themanufacturer for normal service.

3.6.13 Thermal Stability

Thermal stability is considered to be reachedwhen the change in error as consequence ofthermal effects during 20 minutes is less than0.1 times the maximum permissible error forthe measurement under consideration.

3.7 Terms Related to Tests

3.7.1 Type Tests

Series of tests carried out on one meter or asmall number of meters of the same typehaving identical characteristics, selected bymanufacturer to prove conformity with all therequirements of this standard for the relevantclass of meter. These are intended to prove thegeneral qualities and design of a given type ofmeter.

3.7.2 Routine Tests

Tests carried out on each meter to checkconformity with the requirements of thisstandard in aspects which are likely to varyduring production.

3.7.3 Acceptance Test

Tests carried out on samples taken from a lotfor the purpose of acceptance of the lot.

4 CLASSIFICATION

4.1 Meters are classified according to theirrespective class indices, for example, 0.2 S 01'

0.5 S (active energy) and 0.2 S, 0.5 S 01' 1.0 S(reactive energy).

5 RATINGS

5.1 Standard Reference Voltages

The reference voltage shall be one of the valuesas given in Table 1 ( see IS 12360 ).

Table 1 Standard Reference Voltages

Meters for Standard ExceptionalReference Voltage Values

(V) (V)

Connect.ion through 57.7 (100), 63.5 (110) 100 (173)volt.age transformer

Connection through 230 (400). 240 (415) 220 (380).current transformer 250 (433)only

5.2 Standard Basic Currents

The basic currents shall be 1 A or 5 A.

5.3 Rated Maximum Current

The rated maximum currents shall be 1.2, 1.5or 2 times of basic current

NOTE - For requirements other than 1.2 times basiccurrents should be the subject of purchase contract.

5.4 Standard Frequency

Standard value for reference frequency is 50 Hz.

6 GENERAL AND CONSTRUCTIONALREQUIREMENTS

6.1 General

Meters shall be designed and constructed insuch a way as to avoid introducing any dangerin normal use and under normal conditions, soas to ensure especially:

Personal safety against electric shock.

Personal safety against effects of excessivetemperature.

Safety against spread of fire.

5

IS 14697 : 1999

Protection against solid objects, dust andwater.

All parts which are subject to corrosion undernormal conditions shall be effectively protected.Any protective coating shall not be liable todamage by ordinary handling nor damage dueto exposure to air, used under normal workingconditions.

NOTE - For meters for special use in corrosiveatmosphere, additional requirements shall be fixed inthe purchase contract (for example, salt mist test).

6.2 Meter Case

The meter shall have a reasonably dustlmoisture-proof case, which shall be sealed bythe manufacturer in such a way that theinternal parts of the meter are accessible onlyafter breaking such distinctive seal(s).

The covel' shall not be removable without theuse of a tool.

The case shall be so constructed and arrangedthat any non-permanent deformation cannotprevent the satisfactory operation of the meter.

Unless otherwise specified, the meters having acase wholly or partially made of metal, shall beprovided with a protective earth terminal.

6.3 Window

If the cover is not transparent one or morewindows shall be provided for reading thedisplays and observation of the operationindicator if fitted. These windows shall becovered by toughened transparent materialwhich cannot be removed undamaged withoutbreaking the seal(s).

6.4 Terminals, Terminals Block(s) andProtective Earth Terminal

Terminal may be grouped in a terminal block(s)having adequate insulating properties andmechanical strength. In order to satisfy suchrequirements. when choosing insulatingmaterials for the terminal block(s), adequatetesting of materials should be taken intoaccount.

The holes in the insulation material which from Ian extension of the terminal holes shall be ofsufficient size to accommodate also theinsulation of the conductors.

The material of which the terminal block ismade shall be capable of passing the tests givenin ISO 75-1(1993) and ISO 75-2(1993) for atemperature of 135°C and a pressure of 1.8 MPa(Method A).

The manner of fixing the conductors to theterminals shall ensure adequate and durablecontact such that there is no risk of loosening orundue heating. Screw connections transmitting

IS 14697 : 1999

contact force and screw fixings which may beloosened and tightened several times during thelife of the meter, shall screw into metal nuts.

All parts of every terminal shall be such thatthe risk of corrosion resulting from contact withany other metal part is minimized.Electrical connections shall be so designed thatcontact pressure is not transmitted throughinsulating material of the terminal block.

For current circuits, the voltage is considered tobe the same as for the related voltage circuit.

Terminals with different potentials which aregrouped close together shall be protectedagainst accidental short circuiting. Protectionmay be obtained by insulating barriers.Terminals of one current circuit are consideredto be at the same potential.

The terminals, the conductor fixing screws, orthe external or internal conductors shall not beliable to come into contact with terminal covers(if made of metal).

The protective earth terminal, if any:

a) Shall be electrically bonded to theaccessible metal parts;

b) Should, if possible, form part of the meterbase;

c) Should preferably be located adjacent toits terminal block;

d) Shall accommodate a conductor having across-section at least equivalent to themain current conductors but with a lowerlimit of 6 mm2 and an upper limit of16 mm2; and

e) Shall be clearly identified by earthingsymbol.

After installation, it shall not be possible toloosen the protective earth terminal withoutthe use of a tool.

6.5 Terminal Cover(s)

Every terminal block shall be provided with aterminal cover conforming to 6.5.101' 6.5.2.

6.5.1 Short Terminal Cover

The terminals, their fixing screws, and theinsulated compartment housing them shall beenclosed by a cover with a provision for sealing.The cover may be ofthe same size as that of theterminal block. The wiring with this type ofcover may be carried out from the front of themeter board.

6.5.2 Extended Terminal Cover

The terminals, their fixing screws, a suitablelength of external insulated conductor and itsinsulation shall be enclosed by a cover with a

6

provision for sealing. The wiring with this typeof cover shall be carried out from the real' of themeter board.

The fixing screws used on the terminal covel'for fixing and sealing in 6.5.1 and 6.5.2 shall beheld captive in the terminal cover.

When the meter is mounted on the meterboard, no access to the terminals shall bepossible without breaking seal(s) of theterminal cover.

6.6 Clearance and Creepage Distance

The clearances and creepage distances of theterminal block and those between the terminalsand the surrounding parts of the metalenclosure shall be not less than the valuespecified in Table 2.

The clearance between the terminal cover, ifmade of metal, and the upper surface of thescrews when screwed down to the maximumapplicable conductor fitted shall be not lessthan the relevant values indicated in Table 2.

Table 2 Clearances and Creepage Distance

Voltage Phase-to- Minimum MinimumEarth Derived from Clearance Creepage Distance

Rated System (mm) (mm)Voltages

(V)

(1) (2) (3)

Not exceeding 50 0.8 1.2

Not exceed ing 100 0.8 1.4

Not exceeding 150 1.5 1.6

Not exceeding 300 3.0 3.2

Not exceeding 600 5.5 6.3

The reqUlrements of the impulse voltage testshall also be met (see 12.7.6.2).

6.7 Insulating Encased Meter

A meter having a durable and substantiallycontinuous enclosure made wholly of insulatingmaterial, including the terminal cover, whichenvelops all metal parts with the exception ofsmall parts, for example, name-plate screws,suspensions and rivets. If such small parts areaccessible by the standard test finger (asspecified in IS 1401) from outside the case, thenthey shall be additionally isolated from liveparts by supplementary insulation againstfailure of basic insulation or loosening of liveparts. The insulating properties of lacquer,enamel, ordinary paper, cotton, oxide film onmetal parts, adhesive film and sealingcompound, or similar unsure materials, shallnot be regarded as sufficient for supplementaryinsulation.

For the terminal block and the terminal cover ofsuch a meter, reinforced insulation is sufficient.

6.8 Resistance to Heat and Fire

The terminal block, the terminal cover and themeter case shall ensure reasonable safetyagainst spread of fire. They should not beignited by thermic overload of live parts incontact with them. To comply therewith it mustfulfil the tests as specified in 12.4.

6.9 Protection Against Penetration of Dustand Water

The meter shall conform to the degree ofprotection as given below:

IP 51, but without suction in the meter.

6.10 Display of Measured Values

The information can be shown either with anelectromechanical register or an electronicdisplay. In case of an electronic display thecorresponding non-volatile memory shall havea minimum retention time of 5 years.

NOTE - Longer retention time of the non-volatilememory should be the subject of purchase contract.

Jn the case of multiple values presented by asingle display it must be possible to display thecontents of all relevant memories. Whendisplaying the memory, identification of eachtarifflparameter shall be available.

The current tariff shall be indicated. When themeter is not energized; the electronic displayneed not be visible.

The principal unit for the measured valuesshall be kilowatt-hour (kWh) or the Megawatthour (MWh), kVarh or MVarh.

The regi tel' shall be able to record and displaystarting from zero, for a minimum of 1 500 h,the energy corresponding to rated maximumcurrent at reference voltage and unitypower· factor. Register should not rollover inbetween this duration.

NOTE - Values higher than I 500 h should be thesubject of purchase contract.

6.11 Output Device

The meter shall have a test output accessiblefrom the front and be capable of beingmonitored with suitable testing equipment. Theoperation indicator, if fitted, must be visiblefrom the front.

Since the sequence of test output pulses maynot be homogeneous, the manufacturer shallstate the minimum number of pulse countsnecessary to ensure measurement accuracy atleast 1I10th of the specified error limits atvarious points and consistent with desiredresolution.

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IS 14697 : 1999

The resolution of the test output in the form ofpulses or high resolution register, whetheraccessible on the meter Or through externaldisplay, shall be sufficient to conductsatisfactorily accuracy test at the lowest load inless than 5 minutes and starting current test inless than 10 minutes.

7 MARKING OF METERS

7.1 Name Plate

Every meter shall bear the followinginformation if applicable:

a) Manufacturer's name or trade·mark andif required, the place of manufacture.

b) Designation of type (see 3.1.10) and ifrequired, space for approval mark.

c) The number of phases and the number ofwires for which the meter is suitable (forexample, single-phase 2-wire, three-phase3-wire, three-phase 4-wire). Thesemarkings may be replaced by the graphicalsymbols (as per IS 12032 series).

d) The serial number and year ofmanufacture. If the serial number ismarked on a plate fixed to the cover, thenumber is to be marked also on the meterbase.

e) The reference voltage in one of thefollowi ng forms:

- The number of elements if more thanone, and the voltage at the meterterminals of the voltage circuit(s).

-The nominal voltage of the system orthe secondary voltage of the instrumenttransformer to which the meter isintended to be connected.

- Examples of voltage markings areshown in Table 3.

f) Principal unit in which the meter reads,for example, kWh.

g) The rated secondary current of thetransformer(s) to which the meter shouldbe connected for example, thus: -/5A thebasic current and the rated maximumcurrent of the meter may be included inthe type designation.

h) The reference frequency in Hz.j) The meter constant, for example, in the

form; X Wh/imp or X imp/kWh

k) The class index of the meter.m)The reference temperature if different

from 27"C.n) The sign of double square or insulating

encased meters.

NOTE - For special applications, other temperaturevalues can be used according to agreement betweenmanufacturer and purchaser.

8.2 Relative HumidityThe meter shall meet the relative humidityrequirements of Table 5. For combinedtemperature and humidity test (see 12.6.3 ).

Table 5 Relative Humidity

Standard diagrams of connection are given in IAnnex H.

8 CLIMATIC CONDITIONS8.1 Temperature Range

Temperature range of the meter shall be asindicated in Table 4.

Table 4 Temperature Range

IS 14697 : 1999

Information under (a), (b) and (c) may bemarked on an external plate permanentlyattached to the meter cover.The information under (d) to (e) shall bemarked on a name plate preferably placedwithin the meter.The marking shall be indelible, distinct andreadable from outside the meter.If the meter registers energy throughinstrument transformer(s), which areaccounted in the meter constant, thetransformation ratio(s) shall be marked.

Standard symbols may also be used (seeIS 12032 series).

For multi energy meters, the class indices of allthe energy parameters, if different, shall beseparately indicated. In the absence of this, themeter shall be regarded to have the same classindex for all energy parameters.

Table 3 Voltage Markings[ Clause 7.1(e) 1

Specified operation range

Limit range of operation

Limit range for storage and transport

Annual mean

_100 e to + 55°e

-25°C to + GOoe

~25°C to + 700 e

< 75%

Type of Meter Method of Marking Example

(I) (2) (3)

l·phase, 2-wire Voltage between line 240Vand neutral

3-phase, 3-wire 2 x Voltage between 2 x IlOVlines

a-phase. 4-wirc 3 x Voltage between 3xllOj3Vorline and neutral 3 x 63.5 V

3 x 240 V

7.1.1 ac Static watthour meters can also bemarked with BIS Standard Mark (if certified byBIS).

7.2 Connections, Diagrams and TerminalMarking

Every meter shall be indelibly marked with adiagram of connections. For polyphase meter,this diagram shall also show the phasesequence for which the meter is intended. It ispermissible to indicate the connection diagramby an identification figure in accordance withrelevant standards.

If the meter terminals are marked, thismarking shall appear on the diagram.

When a number of meters are connected to asingle distributing mains for registeringelectricity supplied to different consumer loads,separate service lines-phase(s) and neutral,shall be used for each meter. Moreover, inter­connection of phases 01' neutrals of such loadsconnected to different meters must be avoided.Each independently metered consumer loadmust be directly connected to distributingmains through its meter connected in specifiedphase sequence so as to meet accuracyrequirements of this standard.

8

For 30 days, these days being spread ina natural manner over the year < 95%

Occasionally on other days < 85%

The limits of relative humidity as a function ofambient temperature are shown in Annex B.The graph may be modified in line with metro­logical conditions prevalence in the place of use.

9 ELECTRICAL REQUIREMENTS

9.1 Power Consumption

9.1.1 Power Consumption in Voltage CircuitThe active and apparent power consumption ineach voltage circuit of a meter at referencevoltage reference temperature and referencefrequency shall not exceed the values shown inTable 6.

Table 6 Power Consumption in VoltageCircuit Including the Power Supply

( Clause 9.1.1 )

Meters Class of Meters(0.2 S 0.5 Sand 1.0 S)

(1) (2)

Single-phase and polyphase 1.5 Wand 10 VA(per phase)

NOTES

1 The above figures arc mean values. Switching powersupplies with peak values in excess of these arepermitted but attention should be paid to the rating ofassociated voltage transformers.

21n case additional features like remote metering,prepayment metering, etc, arc built into the meter,then additional loss may be allowed as agreed betweenthe supplier and the purchaser

IS 14697 : 1999

Table 8 Voltage Range

For testing see 12.7.3.

9.2 Influence of Supply Voltage

9.2.1 Voltage Range

Voltage range shall be as given in Table 8.

NOTES

1 For the permissible error due to voltage variation (seeTable 13).

2 Extended operating ranges will be the subject ofpurchase contract.

9.3 Influence of Self-Heating

The variation in percentage error due toself·heating shall not exceed the values given inTable 10.

For testing see 12.7.4.

9.4 Influence of Heating

Under normal conditions of use, electricalcircuits and insulation shall not reach atemperature which might adversely affect theoperation of the meter. The temperature rise atany point of the external surface of the metershall not exceed by more than 20 K with anambient temperature at 45°C.

For testing see 12.7.5.

9.5 Insulation

The meter and its incorporated auxiliarydevices if any, shall be such that they retainadequate dielectric qualities, taking intoaccount of the atmospheric influences anddifferent voltages, to which they are subjectedunder normal conditions of use.

The meter shall withstand the impulse voltagetest and the ac high voltage test as specified in12.7.6.

9.6 I=unity to Earth/Phase Fault

This test applies to three·phase four·wiremeters.

During a test under a simulated earth/phasefault condition in one/two of the three lines, allvoltages are increased to 1.1 times the nominalvoltages during 4 h. The neutral terminal of themeter under test is disconnected [rom theground terminal of the meter test equipment(MTE) and is connected to the MTE's line at

Table 10 Variation in Percentage ErrorDue to Self-Heating

( Clause 9.3 )Value of Power Limits of Variation inCurrent Factor Percentage Error for

Meters of Class

0.28 0.58 1.0 S(I) (2) (3) (4) (5)

lMax 1 0.1 I 0.2 I 0.5

lMax 0.5 lagging 0.1 I 0.2 T 0.7

Table 9 Variations Due to Short-timeOver Currents

( Clause 9.2.3 )Value of Power Limits of Variation inCurrent Factor Percentage Error for

Meters of Class.0.28 0.58 1.0 S

(I) (2) (3) I (4) I (5)

I, 1 0.1 I 0.1 I 0.1

0.80 to J.l Vref.

0.70 to 1.2 Vref.

9.2.2 Voltage Dips and Interruptions

Voltage dips and interruptions shall notproduce a change in the register of more than0.001 kWh and the test output shall notproduce a signal equivalent to more than 0.001kWh. These values are based on the ratedcurrent of 5A and 100 V of the meter. For othervoltage and current ratings the value 0.001kWh has to be converted accordingly dependingupon transformation ratio. When the voltage isrestored, the meter shall not have suffereddegradation of its metrological characteristics.

Further, after this test the data from thememory should not be lost.

For testing see 12.7.2.

9.2.3 Short·Time Over Current

Short·time over current shall not damage themeter. The meter shall perform correctly, whenback to its initial working conditions and thevariation of error shall not exceed the valuesshown in Table 9.

The meter shall be able to carry for 0.5 second acurrent equal to 20 times the maximumcurrent.

Specified operating range

Limit range of operation

9.1.2 Power Consumption in Current Circuit

The apparent power taken by each currentcircuit at basic current, reference frequencyand reference temperature shall not exceed thevalue shown in Table 7.

Table 7 Apparent Power Consumption inCurrent Circuit

( Clause 9.1.2 )

Meters Class of Meters(0.2 S, 0.5 Sand 1.0 S)

(I) (2)

Single-phase and polyphase 1.0 VA(per phase)

9

IS 14697 : 1999

which the earth/phase fault has to be simulated( see Annex J ).

In this way the two voltage terminals of themeter under test which are not affected by theearth/phase fault are connected to 1.9 times thenominal phase voltages. During this test thecurrent circuits are set to 50 percent of therated lb' unity power factor and symmetricalload. After the test, the meter shall show nodamage and shall operate correctly.

The change of error measured when the meteris back at nominal working temperature shallnot exceed the limits given in Table lOA.

For testing, see 12.17.

Table lOA Change of Error Due toEarth/Phase Fault

( Clause 9.6 )Value or Power Limits oCVariation inCurrent Factor Percentage Error for

Meters oC Class

0.28 0.58 1.08

(1) (2) (3) I (4) I (5)

Ib 1 0.2 I 0.4 I 0.7

10 ELECTROMAGNETIC COMPATIBI­LITY (EMC)

10.1 Inununity of ElectromagneticDisturbance

The meter shall be designed in such a way theconducted 01' radiated electromagneticdisturbance as well as electrostatic dischargedo not damage nor substantially influence themeter.

NOTE - The disturbances to be considered are:

a) Electrostatic discharge,

b) Electromagnetic HF field, and

c) Fast transient burst.

For testing see 12.8.

10.2 Radio Interference Suppression

The meter shall not generate conducted orradiated noise which could interfere with otherequipment.

For testing see 12.8.5.

11 ACCURACY REQUIREMENTS

11.1 Limits of Error Due to Variation ofthe Current

When the meter is under the referenceconditions given in 12.9.1 the percentage errorshall not exceed the limits for the relevantaccuracy class given in Tables 11 and 12.

If the meter is designed for the measurement ofenergy in both directions, the values inTables 11 and 12 shall apply for each direction.

- - ------- ----

Table 11 Percentage Error Limits(Single-Phase Meters and Polyphase

Meters with Balanced Loads)

(Clause 11.1)

Value of Power Percentage ErrorCurrent Factor Limits for Meters of

Class

"'0:280.5 8 1.0 S

(I) (2) (3) (4) (5)

0.01 h s: Ib < 0.05Ib 1 ±0.4 ± 1.0 -

0.05 lb s: lb s: IMax 1 ± 0.2 ± 0.5 ± 1.0

0.02 lb 5: h < 0.1 h 0.5 lagging ± 0.5 ± 1.0 ± 2.0

O.Bleading ± 0.5 ± 1.0 ± 2.0

O. I Ib 5: Ib s: IMax 0.5 lagging ± 0.3 ± 0.6 ± 1.2

0.8 leading ± 0.3 ± O.G ± 1.2

When specially 0.25 lagging ± 0.5 ± 1.0 ± 2.5req uired by the 0.5 leading ± 0.5 ± 1.0 ± 2.5user: from 0.2 lb to I b

Table 12 Percentage Error Limits(Polyphase Meters Carrying a Single-

Phase Load but with Balanced PolyphaseVoltages Applied to Voltage Circuits)

( Clause 11.1 )

Value of Power Factor Percentage ErrorCurrent of Relevant Limits for Meters of

Element Class

028 0.58 1.08

(1) (2) (3) (4) (5)

0.05 h s: Ib < lMax 1 ± 0.3 ± O.G ± 1.5

0.1 Ib :5 Ib:5 IMax 0.5 lagging ±0.4 ± 1.0 ± 2.0

The difference between the percentage errol'when the meter is carrying a single-phase loadat basic current and unity power factor and thepercentage error when the meter is carryingbalanced polyphase load at basic current andunity power factor, shall not exceed 0.4, 0.8 and1.5 for meters of classes 0.2 S, 0.5 Sand 1.0 Srespectively.

NOTE - When testing for compliance with Table 12 thetest current shaU be applied to each element, in sequence.

11.2 Limits ofError due to Other InfluenceQuantities

Limits of variation in percentage error due tothe change of influence quantities with respectto reference conditions, as given in 12.9.1, shallnot exceed the limits for the relevant accuracyclass given in Table 13.

1l.3 Limits of Error Due to AmbientTemperature Variation

The mean temperature coefficient shall notexceed the limits given in Table 14.

10

IS 14697 1999

·Table 13 Influence Quantities( Clauses 9.2.1 and 11.2 )

Influence Quantities Value for Current Power Limit of Percentage Error(Balanced Unless Otherwise Factor for Meters of Class

Stated)0.2 S 0.5 S LO S

(I) (2) (3) (4) (5) (6)

Voltage variation 0.02 Ib:5: Ib:5: [Max 1 0.1 0.2 0.4(see Note 1) ± 10% 0.05 I b :5 Ib:5 IMaJe O.51agging 0.2 0.4 0.8Frequency variation ± 5% 0.02 lb :S/b:S" IMax 1 0.1 0.2 0.4

0.05 Ib:5 lb :5IMax 0.5 lagging 0.1 0.2 0.4Wave form: 10% of3 ru 0.05 Ib :5 I b :5 [Max 1 0.1 0.1 0.2harmonic in the current(see Note 2)Reversed phase sequence 0.1 Ib 1 0.05 0.1 0.2Voltage unbalance h 1 0.5 1.0 2.0( see Note 4 )Auxiliary voltage ± 15% O.02/b 1 0.05 0.1 0.2(see Note 5)Phase of auxiliary supply 0.021b 1 0.1 0.2 0.4voltage by 120 degree(see Note 5)Continuous magnetic induction lb 1 2.0 3.0 3.0of external origin (see Note 6)Magnetic induction of external lb I 05 LO 2.0origin 0.5 mT (see Note 7)

Electromagnetic HF fields lb 1 1.0 2.0 2.0( see Note 8 )Uperation of accessories 0.02 h 1 0.05 0.1 0.2(see Note 9)Continuous abnormal magnetic lb 1 4.0 4.0 4.0induction of external origin(see Note 10)Abnormal' ac magnetic lb 1 4.0 4.0 4.0induction of external origin(10 mT) (see Note 10)

I) With due cognizance of uncertainty of measurement.

NOTES

1 For the voltage ranges from -20 to -10 percent and +10 to +20 percent the limits of variation in percentageerror are three times the values given in Table 13.

Below 0.8 Vref and up to 0.7 Vref, the said limits are five times the value given in Table 13.

Below 0.7 Vrefthe error of the meter may vary between +10 percent and -100 percent.

2 The distortion factor of the voltage shall be less than 1 percent. The variation in percentage error shall bemeasured under two conditions. The peak of third harmonic in the fIrst measurement in phase and in the secondmeasurement in antiphase of the peaks of the fundamental current. For polyphase meters, the voltage circuitshall be energized in parallel and the current circuit in series.

4 The polyphase meter shall measure and register within the variation in percentage error limits shown inTable 13 if one or two-phase of the 3-phase network are interrupted, provided the reference phase is available,that is, V-phase for three-phase 3-wire meters and neutral for 3-phase 4-wire meters. However. the operation ofthe meter shall not be affected by such removal of reference phase. Applicable for active energy meters only.

5 Applicable only if the auxiliary supply voltage is not internally connected to the voltage measuring circuit.

6 The test conditions are specified in 12.10.

7 A magnetic induction of external origin of 0.5 mT produced by a current of the same frequency as that of thevoltage applied to the meter and under the most unfavourable conditions of phase and direction shall not cause avariation in the percentage error of the meter exceeding the values shown in Table 13. The test conditions arespecified in 12.10.

8 The test conditions are specified in 12,8.3.

9 Such an accessory, enclosed in the meter case is energized intermittently, for example the electromagnet of amultirate register.

10 The test conditions are specified in clause 12.10. In the event of logging of abnormal magnetic induction withdate and time, the positive variation may be beyond the limit of 4 percent, but not exceeding a power valueequivalent to the product of rated voltage and maximum current.

11

IS 14697 : 1999

It is preferable that the connection to theauxiliary device is/are marked to indicate thecorrect method of connection, if theseconnections are made by means of plugs andsockets, these connections should be irreversible.

The determination of the mean temperaturecoefficient for a given temperature shall bemade over a 30°C temperature range 15°Cabove and 15°C below that temperature, but inno case, the temperature shall not exceed thespecified operating temperature range.

11.4 Starting and Running with No-Load

For these tests, the conditions and the values ofthe influence quantities shall be as stated in12.9.1 except for any changes specified below.

11.4.1 Initial Start·up of the Meter

The meter shall be fully functional within 5safter the rated voltage is applied to meterterminals,

11.4.2 Running with No-Load

When the voltage is applied with no currentflowing in the current circuit, the test output ofthe meter shall not produce more than oneoutput pulse count.

For testing see 12.12.

11.5 Starting Current

The meter shall start and continue to registerat the current shown in Table 15.

11.6 Meter Constant

Relation between the test output and theindication in the display shall comply with themarking on the name plate.

Table 14 Temperature Co-efficient

( Clause 11.3 )

Value of Power Mean TemperatureCurrent Factor Coefficient for

Meter of Class

0.2 S 0.5 S 1.0 S

(1) (2) (3) (4) (5)

From 0.05 Ib to lMax 1 0.01 0.03 0.05

From 0.1 Ib to IMax 0.5 lagging 0.02 0.05 0.07

Table 15 Starting Currents

( Clause 11.5 )

Value of Power Class of MeterCurrent Factor

0.2 S 0.5 S 1.0 S

(1) (2) (3) I (4) I (5

Percentage of Ib 1 0.1 I 0.1 I 0.2

11.7 Repeatability of Error Test

Repeatability of error at 5 percent hand UPFload shall not exceed 0.1 for class 0.2 S, 0.25 forclass 0.5 Sand 0.5 for class 1.0 S meters asmeasured by the dispersion method (see 12.16 ).

12 TESTS AND TEST CONDITIONS

12.1 Test Conditions

All tests are carried out under referenceconditions unless otherwise stated in therelevant clause.

12.2 Classification of Tests

The schedule and recommended sequence isgiven in Table 16.

In case of modifications to the meter made afterthe type test and affecting only part of themeter, it will be sufficient to perform limitedtests on the characteristics that may be affectedby the modification.

12.2.1 Numbe,· of Samples and Criteria forConformity

Type tests shall be applied to three testspecimens; in the event of one specimen failingto comply in any respect, further threespecimens shall be taken all of which shallcomply with the requirements of the standard.

12.2.2 Schedule of Acceptance Tests

Required tests are marked with 'A' in Table 16.

12.2.2.1 Recommended sampling plan andcriteria for acceptance

A recommended sampling plan and the criteriafor acceptance of the lot are given in Annex E.

12.2.3 Schedule of Routine Tests

12.2.3.1 Required tests are marked with 'R' inTable 16.

12.3 Test of Mechanical Requirements

12.3.1 Shock Test

The test shall be carried out as pel' IS 9000(Part 7/Sec 1 to 5 : 1979) under the foUowingconditions:

- Meter is non-operating condition, withoutthe packing.

- Half-sine pulse.- Peak acceleration: 40 g (400 mls 2).- Duration of the pulse: 18 ms.

- No of shock: two in both direction of threemutual perpendicular axes (Total of 12shocks).

12

Table 16 Schedule of Type Tests

( Clause 12.2)

81 Test Clause A RNo. ReferenceI Test of Insulation Properties 12.7.61.1 Impulse voltage test 12.7.6.21.2 ac High voltage test 12.7.6.3 A R1.3 Insulatlon test. 12.7.6.4 A R2 Test of Accuracy Requirements 12.92.1 Teston limits of error 11.1 A R2.2 Interpretation of test results 12.152.3 Test of meter constant 12.14 A2.4 Test of starting condition 12.13 A R2.5 Test of no· load condition 12.12 A R2.6 Test of ambient temperature 12.11

influence2.7 Test of repeatability of error 12.16 A2.8 Test of influence Quantities 12.103 Test of Electrical Requirement 12.73.1 Test for power consumption 12.7.1 A3.2 Test of influence of supply voltage 12.7.23.3 Test of influence short time

overcurrent 12.7.33.4 Test of innucnce of self-heating 12.7.43.5 Test of innucnce of heating 12.7.53.6 Testofimmunity to earth/phase fault 12.174 Test for Electromagnetic

Compatibility 12.84.1 Radio interference measurement 12.8.54.2 Fast transient burst test 12.8.44.3 Test of immunity to electrostatic

discharges 12.8.24.4 Test of Immunity to electromagnetic

HF field 12.8.35 Test for Climatic Influences 12.65.1 Dry heat test 12.6.15.2 Cold test 12.6.25.3 Damp heat cyclic test 12.6.36 Test for Mechanical 12.3

Requirements6.1 Vibration test 12.3.26.2 Shock test 12.3.16.3 Spring hammer test 12.3.36.4 Protection against penetration of

dust and water 12.56.5 Test of resistance to heat and fire 12.4

A = Acceptance test; R = Routme test

After the test, the meter shall show no damageor change of information. After the test,variation in percentage error shall not exceedthe 50 percent of accuracy class index at I b,0.051b, and I m"x (at cos $ = 1).

12.3.2 Vibration TestThe test shall be carried out as per IS 9000(Part 8) under the following conditions:

- Meter in non-operation condition. Withoutthe packing.

- Frequency range: 10 - 150 - 10 Hz.

- Transition frequency: 60 Hz.

- f < 60 Hz constant amplitude of movement0.15 mm.

13

IS 14697 : 1999

- f> 60 Hz constant acceleration 2 g (I g =9.8 m/s2).

- Single point control.

- Number of sweep cycles per axis: 10.

NOTE - 10 sweep cycles = 75 minutes.

After the test the meter shall show no damageor change of the information. After the testvariation in percentage error of the meter errorshall not exceed 50 percent of class index at0.05 lb' basic current and maximum current (atCos $ = 1).

12.3.3 Spring Hammer TestThe mechanical strength of the meter caseshall be tested with a spring hammer[IEC 60068-2-75 (1997-05)].

The meter shall be mounted in its normalworking position and the spring hammer shallact on the outer surfaces of the meter cover(including windows and on the terminal coverwith a kinetic energy of 0.22 Nm ± 0.05 Nm.

The result of the test is satisfactory if the metercase and terminal cover do not sustain damagewhich could affect the function of the meter andit is not possible to touch live parts. Slightdamage which doesn't impair the protectionagainst indirect contact or the penetration ofsolid objects, dust and water is acceptable.

12.4 Test of Resistance to Heat and Fire

The test shall be carried out according toIS 11000 (Part 2/Sec I) with the followingtemperatures:

- Terminal block: 960 ± 15'C- Terminal cover and meter case: 650 ± 100e- Duration of application: 30 s ± Is.

The contact with the glow wire may occur atany random location. If the terminal block isintegral with the meter base, it is sufficient tocarry out the test only on the terminal block.

12.5 Test ofProtection Against Penetrationof Dust and Water

The test shall be carried out according toIS 12063 under the following conditions:

a) Protection against penetration of dust

- Meter in non-operating condition andmounted on an artificial wall.

- The test should be conducted with samplelengths of cable (exposed and sealed) ofthe types specified by the manufacturer inplace.

- 1st characteristic digit: 5 (IP 5X) resp.

Any ingress of dust only be in a quantity notimpairing the operation of the meter, and notimpairing its dielectric strength (insulatingstrength).

IS 14697 : 1999

For testing see 12.7.6.4.b) Protection against penetration of water

- Meter in non·operating condition.- 2nd characteristic digit: 1 (IP XI).

Any ingress of water must only be in a quantitynot impairing the operation of the meter, andnot impairing its dielectric strength (insulatingstrength).

For testing see 12.7.6.4.

12.6 Test for Climatic Influences

After eacb of the climatic tests, the meter shallshow no damage or change of the information.These tests should not affect the functioning ofthe meters.

12.6.1 Dry Heot Test

The test shall be carried out according torelevant section of IS 9000 (Part 3/Sec 3) underthe following conditions:

- Meter in non-operating condition.

- Temperature: + 70 ± 2°C.

- Duration of the test: 72 hours.

12.6.2 Cold Test

The test shall be carried out according torelevant section of IS 9000 (part 2/Sec 3) underthe following conditions:

- Meter in non·operating condition.

- Temperature: - 25 ± 2°C.

- Duration of the test: 72 hours.

12.6.3 Damp Heat Cycle Test

The test shall be carried out according torelevant section of IS 9000 (part 5/Sec 2) underthe following conditions:

- Meter in operating condition.- Voltage and auxiliary circuits energized

with reference voltage- Without any circuits in the current

circuits.- Upper temperature 40°C ± 2°C.- No special precautions shall be taken

regarding the removal of surface moisture.- Duration of test: 6 cycles.

Twenty four hours after the end of this test themeter shall be submitted to the following tests:

a) An insulation test according to 12.7.6.4.b) A functional test. The meter shall show no

damage or change of information.

The damp heat test also serves as a corrosiontest. The result is judged visually. No trace ofcorrosion likely to affect the functionalproperties of the meter shall be apparent.

14

12.7 Test of Electrical Requirements

12.7.1 Test of Power Consumption

The power consumption in the voltage andcurrent circuit shall be determined at referencevalues of the influencing Quantities given in12.9.1 by any suitable method. The overallaccuracy shall be better than 5 percent.

12.7.2 Test of Influence of Supply Voltage

The test shall be carried out under thefollowing conditions:

- Meter in operating condition.- Voltage and auxiliary circuits energized

with reference voltage.- Without any current in the current

circuits.

a) Voltage interruptions ofVref= 100percent- Interruption time: 1 s.- Number of interruptions: 3.- Restoring time between interruptions:

50 ms.See also Annex C.

b) Voltage intenuption ofVref= 100 percent- Interruption time: 20 ms.- Number of interruptions: 1.

See also Annex C.c) Voltage dips ofVref= 50 percent

- Dip time: 1 min.- Number of dips: 1.

see also Annex C.

For requirement see 9.2.2.

12.7.3 Test of Influence of Short-Time OuerCurrents

The test circuit shall be practically non­inductive.

After the application of the short-time overcunent with the voltage maintained at theterminals, the meter shall be allowed to returnto the initial temperature with the voltagecircuit(s) energized (about one hour). Forrequirement see 9.2.3.

12.7.4 Test of Influence of Self-Heating

The test shall be canied out as follows:

After the voltage circuits have been energizedat reference voltage for at least 2h, meterswithout any current in the current circuits, the"ated maximum current shall be applied to thecurrent circuits. The meter error shall bemeasured at unity power-factor immediatelyafter the current is applied and then atintervals short enough to allow a correctdrawing to be made of the curve of errorvariation as a function of time.

The test shall be carried out for at least 1 handin any event until the variation of errol' during20 min does not exceed 0.1 percent or themeasurement uncertainties whichever isgreater.

The same test shall be carried out than at 0.5(lagging) power factor..

The variation of error, measured as specified,shall not exceed the values given in Table 10.

12.7.5 Test of Influence of HeatingWith each current circuit of the meter carryingrated maximum current and with each voltagecircuits (and with those auxiliary, voltagecircuits which are energized for periods oflonger duration than their thermal timeconstants) carrying 1.15 times the referencevoltage, the temperature rise of the externalsurface shall not exceed by more than 20 K, withthe ambient temperature between 25°C to 45°C.During the test, the duration of which shall be2 h, the meter shall be not exposed to draughtor direct solar radiation.

After the test, the meter shall show no damageand shall comply with the dielectric testsof 12.7.6.4.

12.7.6 Test of Insulation Properties

12.7.6.1 General test conditions

The test shall be carried out only on a completemeter with its cover (except when indicatedhereafter) and terminal cover, the terminalscrews being screwed down to maximumapplicable conductor fitted in the terminals.Test procedure shall be in accordance withIS 2071 (Part 1).

The impulse voltage tests shall be carried outfirst and the ac voltage tests afterwards.

During type tests, the dielectric property testsare considered to be valid only for the terminalarrangement of the meter which has undergonethe tests. When the terminal arrangementdiffer, all the dielectric property tests shall becarried out for each arrangement.

For the purpose of these tests, the 'earth' hasthe following meaning:

a) When the meter case is made of metal,the earth is the case itself placed on a flatconducting surface.

b) When the meter case or only a part of it ismade of insulating material, the earth is aconductive foil wrapped around the meter,touching all accessible conductive partsand connected to the flat conductingsurface on which the meter base is placed.Where the terminal cover makes itpossible, the conductive foil shall approachthe terminals and holes for the conductorswithin a distance of not more than 2 em.

15

IS 14697 : 1999

During the impulse and the ac voltage tests,the circuits which are not under test areconnected to the earth as indicated hereafter. Aflashover (capacitance discharge) is notnecessarily a criterion of failure as this mayoccurs in a position that does not damage andthe manufacturer shall decide, whether or notto eliminate the cause, provided other criteriaof acceptance are met.

In this sub·clause, the expression all theterminals means the whole set of the terminalsof the current circuits, voltage circuits and, ifany, auxiliary circuits having a referencevoltage over 40 V.

These shall be made in normal conditions ofuse. During the test, the quality of theinsulation shall not be impaired by dust orabnormal humidity.

Unless otherwise specified, the normalconditions for insulation test are:

ambient temperature 20°C to 35°C.

relative humidity 45 percent to 95 percent.

atmospheric pressure 86 to 106 kPa(860 mbar to 1 060 mbar).

12.7.6.2 Impulse voltage testThe impulse of 6 kV is applied ten times withone polarity and then repeated with the otherpolarity. The minimum time between theimpulses shall be 3 second. The waveformand the generator characteristics shallbe in accordance with lEC 61000-4-5 (1995)'Electromagnetic compatibility (EMC) -Part 4 :Testing and measurement techniquesSection 5 : Surge Immunity test'.

a) Impulse voltage tests for circuits andbetween the circuits. The test shall bemade independently on each circuit (orassembly of circuits) which are insulatedfrom the other circuits of the meter innormal use. The terminals of the circuitswhich are not subjected to impulse voltageshall be connected to earth.Thus, when in normal use the voltage andthe current circuits of a measuringelements are connected together, the testshall be made on the whole. The other endof the voltage circuit shall be connected toearth and impulse voltage shall be appliedbetween the terminal of the current circuitand earth. When several voltage circuitsof a meter have a common point, this pointshall be connected to earth and theimpulse voltage successively appliedbetween each of the free ends of theconnections (or the current circuitconnected to it) and earth.When in normal use, the voltage and thecurrent circuits of the same measuring

IS 14697 : 1999

(I) (2)

Test Points of Application or tbe Test VoltageVoltage(r.m.s.)

Table 17 ac Voltage Tests

( Clause 12.7.6.3 )

a) Between on the one hand all the currentand voltage circuits as well the auxiliarycircuits whose reference voltage is over40 V, connected together, and, on theother hand, earth ( see Note 1 )

b) a visual inspection for compliance withthe conditions of 6. 7

c) Between on the one hand all conductiveparts in side the meter, connectedtogether and, on the other hand, allconductive parts outside the meter casethat are accessible with the lest fingerconnected together ( see Note 2 )

12.7.6.4 Insulation resistance test

The insulation resistance test shall be carriedout in accordance with Table 18. The voltageshall be applied for a minimum of one minuteor more for the pointer of the insulation testerto have come practically to rest.

NOTES

1 The test in item (a) of Part B is to be carried out, Withthe case closed, the cover and terminal cover in place.

2 The test in item (c) of Part B is not necessary, if test 10

item (b) leaves no doubt.

40 V(for test in

item c)

4 kV B) Additional tests for insulating encased meters(For test initem a)

2 kV A) Test to be carried out with the case closed,and terminal cover in place

a) Between, on the one hand all the currentand voltage circuits as well as theauxiliary circuits whose reference voltageis over 40 V, connected together, and, onthe other hand, earth

b) Between circuits not intended to beconnected together in service

element are separated and appropriatelyinsulated (for example, each circuitconnected to measuring transformer) thetest shall be made separately on eachcircuit.

The impulse voltage shall be appliedbetween all the electric circuits and earth.

During the test of a current circuit, theterminals of the other circuits shall beconnected to earth and the impulsevoltage shall be applied between one oftheterminals of the current circuit and earth.During the test of a voltage circuit, theterminals of the other circuits and one ofthe terminals of the voltage circuit undertest shall be connected to earth and theimpulse voltage shall be applied betweenthe other terminal of the voltage circuitand earth.

The auxiliary circuits intended to beconnected either directly to the mains orto the same voltage transformers as themeter circuits and with a referencevoltage over 40 V shall be subjected to theimpulse voltage test in the sameconditions as those already given forvoltage circuits. The other auxiliarycircuits shall not be tested.

b) Impulse voltage test of electric circuitsrelative to earth. All the terminals of theelectric circuits of the meter, includingthose of the auxiliary circuits with areference voltage over 40 V, shall beconnected together.

The auxiliary circuits with a referencevoltage below or equal to 40 V shall beconnected to earth.

12.7.6.3 ac Voltage test

Table 18 Insulation Resistance Test

(3)

5M11

InsulationResistance

(2)

Points or Application of theTest Voltage

(I)

TestVoltage

500 * 50 a) Between, on the one hand all theV dc current and voltage circuits as

well as the auxiliary circuitswhose reference voltage is over40 V, connected together, and, onthe other hand. earth

b) Between circuits not intended to 50 Mnbe connected together in service

The ac voltage test shall be carried out inaccordance with Table 17 for type test andacceptance test of new meters. For anysubsequent test, the voltage applied shall be 80percent of the test voltage indicated in the table.

During the test no flashover, disruptivedischarge, puncture shall occur.

The test voltage shall be substantiallysinusoidal, having a frequency between 45 Hzand 55 Hz, and applied for one minute. Thepower source shall be capable of supplying atleast 500 VA.

During the tests relative to earth the auxiliarycircuits with reference voltage equal to or below40 V shall be connected to earth.

NOTE - Where two or more voltage circuits arepermanently joined together. the combination may betreated as one circuit for this test.

16

8kV

4

10

12.8 Test for Electromagnetic Compatibility(EMC) and Electromagnetic Interference (EMI)

12.8.1 General Test Conditions

For all these tests, the meter shall be in itsnormal working position with the cover andterminal cover in place. All parts intended to beearthed shall be earthed.

After these tests, the meter shall show nodamage or change of information.

12.8.2 Test for Immunity to Elect1'OstaticDischarge ( ESD )

The test shall carried out according to IEC61000-4-2 (1995), 'Electromagnetic Compatibi­lity (EMC) - Part 4: Testing and measurementtechniques - Section 2 : Electrostatic dischargeimmunity test' under the following conditions:

- Contact Discharge

- Test Voltage

- Test severity level

- Number of discharges:

- Voltage and auxiliary circuits energizedwith reference voltage.

- Without any current in the currentcircuits and the current terminal shouldbe open circuit.

The application of the electrostatic dischargeshall not produce a change in the register ofmore than 0.00 I kWh and the test output shallnot produce a signal equivalent to more than0.001 kWh. These values are based on the ratedcurrent of 5A and 100 V of the meter. For othervoltage and current ratings the value 0.001kWh has to be converted accordingly,depending on the transformation ratios.

After application of the electrostatic dischargethe meter shall show no damage or change ofinformation and shall stay within the accuracyrequirement of this standard.

12.8.3 Test for Immunity to Electromagnetic HFFields

The test shall be carried out according toIEC 61000-4-3 (1998) 'Electromagenetic compa­tibility (EMC) - Part 4: Testing and measure­ment techniques - Section 3: Radiated, radiofrequency, electromagnetic field immunity test'under the following conditions;

- Voltage and auxiliary circuits energizedwith reference voltage.

- Frequency band: 80 MHz to 1000 MHz.

- Test field strength: 10 Vim.

- Test severity level: 3.

17

IS 14697 : 1999

a) Without any current in the transformercircuits and the current should be opencircuit.

The application of the HF field shall notproduce a change in the register of morethan 0.001 kWh and the test output shallnot produce a signal equivalent to morethan 0.00 I kWh. These values are basedon the rated current of 5A and 100 V ofthe meter. For other voltage and currentratings the value 0.001 kWh has to beconverted accordingly, depending ontransformation ratios.

b) With basic current h and power factorequal to unity, at sensitive frequencies orfrequencies of dominant interest, thevariation of enol' shall be within the limitgiven in Table 13.

12.8.4 Fast Transient Burst Test

The test shall be carried out according toIS 14700 (part 4/Sec 4): 1999/1EC 61000-4-4,under the following conditions:

a) Without any current in the current circuitand current terminals shall be open circuit.

Meter in operating condition

- voltage and auxiliary circuits energizedwith reference voltage;

- test voltage on the current and voltagecircuit: 4kV

- duration of the test: 60 s

- tested as table-top equipment

b) With basic current I b and power factorequal to 1.

- voltage and auxiliary circuits energizedwith reference voltage

- test voltage on the current and voltagecircuit: 2 kV

- test voltage on the auxiliary circuitswith a reference voltage over 40 V: 1 kV

- duration of the test: a fast transientburst of Is commences the test, followedby a 300 s non-active period. The testcycle is then repeated until a minimumtest time of 10 min has been completed(the actual test time will depend on theresolution of the meter register; aresolution of at least 0.2%, 0.3% and0.4% is required for 0.2 S, 0.5 Sand1.0 S respectively)

- tested as table-top equipment

IS 14697 : 1999

The test voltage shall be applied between:

the terminals of each circuit normallyconnected to mains; any twoindependent circuits having referencevoltage over 40 V and each independentcircuits having reference voltage over40 V and earth.

The qualifying conditions for the tests are:

a) In case of (a) above: during the test,there shall not be a change in theregister of more than 0.001 kWh and thetest output shall not produce a signalequivalent to more than 0.001 kWh.These values are based on the ratedcurrent of 5 A and reference voltage100 V of the meter. For other voltageand current ratings the value 0.001kWh has to be converted accordingly.

b) In case of (b) above: the advancement inregistration during this test shall notvary by more than 2%, 3%, or 4% formeters of class 0.2 S, 0.5 S, and 1.0 Srespectively from a test under the sameload conditions without application ofthe transients.

12.8.5 Radio Interference Measurement

The test for radio interference shall be carriedout for the frequencies from 0.15 MHz to30 MHz and for the frequencies form 30 MHz to300 MHz as per IS 6842.

12.9 Test of Accuracy Requirements

12.9.1 General Test Conditions

Determination of meter errors for the purposeof verification of accuracy requirement ( see 11 )and variation of such errors for the purpose ofother requirements shall be carried out in ameter testing station having Meter TestingEquipment of relevant accuracy class as laiddown in IS 12346.

The following test conditions shall bemaintained:

a) The meter shall be tested in its case withcover in position; all parts intended to beearthed shall be earthed;

b) Before any tests are made, the ci.rcuitsshall have been energized for a time toreach thermal stability;

c) In addition, for polyphase meters;

- The phase sequence shall be as markedon the diagram of connections.

- The voltages and currents shall besubstantially balanced (see Tables 19and 20).

18

Table 19 Voltage and Current Balance(Clause 12.9.1)

Polyphase Meters Class of Meters

0.2 S 0.5 S 1.0 S(1) (2) (3) (4)

Each of the voltages between ±1% ±1% ±1%line and neutral or betweenany two lines shall not differfrom the average correspon-ding voltage by more than

Each of the currents in the ±1% ±1% ±2%current circuit shall not differfrom the average current bymore than

The phase disp lace me nts of 2 degree 2 degree 2 degreethese currents from thecorresponding line to neutralvoltage, irrespective of thepower factor, shall not differfrom each other by more than

d) The minimum test period at any test pointshall contain sufficient number of cycles(more than 1 000) to take careinstantaneous power variation within acycle. The maximum test period ishowever determined by homogeneity andresolution oftest output ( see 6.11 ).

e) The reference condition shall be asspecified in Table 20.

12.10 Test ofInfluence Quantities

It shall be verified that the requirements ofinfluence quantities as fixed under 11.1and 11.2 are satisfied. Test for variation causedby a particular influence quantity should beperformed independently with all otherinfluence quantities at their referenceconditions (see Table 20).

The continuous magnetic induction of 67 milliTesla ± 5% (see Note 6 under Table 13 ) shall beobtained at a distance of 5 mm from the surfaceof the pole, by using the electromagnetaccording to Annex D energised with a decurrent. The magnetic field shall be applied toall surfaces of the meter. The value of themagneto-motive force to be applied shallgenerally be 1 000 ampere turns.

The magnetic induction may be obtained byplacing the meter in the centre of a circular coiLOne metre in mean diameter, of square sectionof small radial thickness relative to thediameter, and having 400 ampere-turns.The continuous 'abnormal' magnetic inductionof 0.2 Tesla ± 5% (see Note 10 under Table 13 )shall be obtained at a distance of 5 mm fromthe surface of the pole, by using theelectromagnet according to Annex D energizedwith a de CU1'l'ent. The magnetic field shall beapplied to all surfaces of the meter. The valueof the magneto-motive force to be applied shallgenerally be 10 000 ampere turns.

IS 14697 : 1999

Table 20 Reference Conditions

( Clauses 12.9.1 and 12.10 )

Innuence Reference Permissible ToleranceQuantity Value

0.2 Sand 0.5 S 1.0 S

(I) (2) (3) (4)

Ambient temperature Reference temperature or in its ::I:: 2°e ± 2°e( see Note I ) absence 27°C

Voltage Reference voltage ( see Note 3 ) ± 1% ± 1%

Frequency Reference frequency ( see Note 3 ±0.3% ::1::0.5%

Waveform Sinusoidal voltage and current Distortion factor less than 2% Distortion factor lessthan 2%

Magnetic induction of Magnetic induclion equal to zero Induction value which causes 0.05 mTexternal origin at the ( see Note 4 ) a variation oferror notgreaterreference fTequency than 0.1 % (0.2 S) and 0.2%

(0.5 S). but. in any case shouldnot be greater than 0.05 mT(see Note 2)

NOTES

1 If the tests are made at a temperature other than the reference temperature, including permissible tolerances, theresults shall be corrected by applying the appropriate temperature coefficient of the meter.

2 The test consists of:

a) For a single·phase meter, determining the errors at first with the meter normally connected to the mains andthen after invertmg the conditions to current circuils as well as to the voltage circuits. Half of the differencebetween the two errors is the value of the variation of error. Because of the unknown phase of the external field.The test has to be made at 0.1 lb at unity powel' factor and 0.2 lb at 0.5 lag power factor.

b) For a three-phase meter making three measurements at 0.1 Ib at unity power factor after each of which theconnections to the current Circuits and voltage circUits are changed over 120" while the phase sequences is notaltered. The greatest difference between each of the errors so determined and their average value is the valueof the variation of error.

3 The reference conditions for voltage and frequency apply to both the measuring circuit and the aUXiliarysupply(lCs).

4 ThiS magnetic Induction is that at the place of test without the presence of the meter and its connections.

The abnormal ac magnetic induction of 10 mT(see Note 10, Table 13) shall be obtained byplacing the meter at various orientation in thecenter of a circular coil of square section (G.D.400 mm, J.D. 320 mm, Depth 45 mm, 2800 AT)produced by a current of the same frequency asthat of the voltage applied to the meter andunder the most unfavorable conditions of phaseand direction.

12.11 Test of Ambient TemperatureInfluence

It shall be verified that the ambient temperatureinfluence as fixed under 11.3 is satisfied.

12.12 Test of No-Load Condition

For this test the current circuit must be opencircuit and a voltage of 115 percent of thereference voltage shall be applied to the voltagecircuits.

The minimum test period shall be 20 times theactual test period of starting current. The

19

maximum test period shall be limited to200 minutes.

During this test the test output of the meter shallnot produce more than one output pulse/count.

12.13 Test of Starting Conditions

It shall be verified that the startingrequirements as fixed under 11.5 are satisfied.

12.14 Test of Meter Constantl Registration

The requirement of 11.5 shall be verified at onetest point, preferably at 1Max UPF.

Although this verification is not required formeters having test output in the form of highresolution register, a long period registrationtest shall be performed at this test points toverify conformity of registration error, asindicated by the display of the meter and asdistinct from any other external display usedfor testing purpose, within the limits specifiedin Table II.

IS 14697 : 1999

12.15 Limits of error and Interpretation ofTest Results

a) Limits of errol' as specified in 11.1 shallbe verified.

b) Certain test results may fall outside thelimits indicated in Tables II and 12. Owingto uncertainties of measurements andother parameters capable of influencingthe measurements. However, if by onedisplacement of the zero line parallel toitself by no more than the limits indicatedin Table 21, all the test result are broughtwithin the limits indicated in Tables 11and 12, the meter type shall be consideredacceptable.

c) If the tests are made at a temperatureother than the reference temperature,including permissible tolerances, theresults shall be corrected by applying theappropriate temperature coefficient of themeter.

Table 21 Interpretation of Test Results

( Clauses 11.1 and 12.15 )

Class of Meters

0.2 S 0.5 S 1.0 S

(1) (2) (3) (4)

Permissible displacement. of 0.1 0.2 0.5the zero line, percent

12.16 Repeatability of Error Test

Test shall be carried out at 0.05 lb' lb at UPFload under reference test conditions. Twentyerrol' samples shall be taken at time· intervalsof 30 minutes. Identical test condition shall bemaintained through out the test.

For acceptance test six error tests may becarried out at time interval of at least 5 minutes.

12.17 Test of Immunity to Earth/PhaseFault

It shall be verified that the earth/phase faultrequirements as fixed under 9.6 are satisfied.For test diagram, see Annex J.

20

IS 14697 : 1999

ANNEXA( Clause 2)

9000

IS No.1401: 1970

4905:19686842: 1977

LIST OF REFERRED INDIAN STANDARS

Title IS No. TitleAccessbility test probes (first 11000 (Part 21 Fire hazard testing: Part 2 Testrevision) Sec 1) : 1984 methods, Section 1 Glow-wire

2701 (Part 1) : Method for high voltage testing: and guidance1974 Part 1 General definitions and 11731 (Part 1) :Methods of tests for determi-

test requirements 1986 nation of flammability of solidMethods for random sampling electrical insulating material

when exposed to an ignitingLimits of electromagnetic source: Part 1 Horizontalinterference specimen methodBasic environmental testing 12032 series Graphical symbols for diagramsprocedures for electronic and in the field of eletrotechnologyelectrical items: 12063 : 1987 Classification of degrees of pro-

(part 2/Sec 3): Cold test, Section 3 Cold test for techon provided by enclosures of1977 non-heat dissipating items with electrical equipment.

gradual change of temperature 12346 : 1999 Testing equipment for electrical I(Part 3/Sec 3): Dry heat test, Section 3 Dry energy meters (first revision)1977 heat test for non-heat 12360: 1988 Voltage bands for electrical

dissipating items with gradual installations including preferredchange of temperature voltages and frequency

(Part 5/Sec 2): Damp heat (cyclic) test, Section 13010: 1990 ac Watthour meters, class 0.5,11981 2 12+12h cycle and 2(Part 7/Sec 1 Impact test (Sections 1 to 5 in 13779 : 1999 ac Static watthour meters, class Ito 5) : 1979 one volume) 1 and 2~ Specification ({irst(Part 8) : 1987Vibration (sinusoidal) test revision)

ANNEXB( Clause 8.2 )

RELATIONSHIP BETWEEN AMBIENT AIR TEMPERATURE AND RELATIVEHUMIDITY

L1MATIC CONDITIONSHAT DO OCCURN PRACTICE

CLIMATIC CONDITIONSHAT DO NOT OCCURN PRACTICE

75 85 i5 100 "RELATIVE HUMIDITY

T

\ \'-, VI

\.', .-,

r' r:-"r-...: ...:: '" .

"'- ... '.~ '"3 ~

,1 I , C

: TI , I

o

"C70

UMITS FOR EACH PERIOD OF 30 DAYS SPREAD IN ANATURAL MANNER OVER ONE YEARLIMITS OCCASIONALLY REACHED ON OTHER DAYSANNUAL MEAN

21

IS 14697 : 1999

ANNEXC(Clause 12.7.2)

VOLTAGE WAVE FROM THE TESTS OF INFLUENCE OF SUPPLY VOLTAGE

o

50~ 50 ma-

11 10 10 I

FTG. C\ VOLTAGE INTERRUPTIONS OF t>U = 100%, Is

FIG. Cz VOLTAGE INTERRUPTIONS OF t>U = 100%, 20 ms

~1 1------1, 1 mIn

FIG. C3 VOLTAGE INTERRUPTIONS OF t>U = 50%

22

IS 14697 : 1999

ANNEXD( Clause 12.10 )

ELECTROMAGNET FOR TESTING THE INFLUENCE OFEXTERNALLY-PRODUCED MAGNETIC FIELD

(All dimensions in miIJimetres)

.J.

•I • I

·f I-f---+ J..... __ ~, ,I I ,

: .

1&S

I

I II I •--rt.--I I ,,

114-

Meter Under Test

. -,.. -- Core Lamination(I Wlkg)

•,~ ~-+__""'+-''"-_+-..J 80bbin

L ICu Wir~:!oOOO TurDs

0.'" @'O.~O mml

t---+----f -110 A lC)

23

IS 14697 : 1999

ANNEXE( Clause 12.2.2.1 )

RECOMMENDED SAMPLING PLAN

E-l LOT

E-l.l In any consignment, all the meters of thesame type and rating manufactured by thesame factory during the same period shall begrouped together to constitute a lot.

E-1.2 Sample shall be tested from each lot forascertaining the conformity of the meters to therequirements of specified acceptance test.

E-2 SCALE OF SAMPLING

E-2.1 The number of meters to be selected fromthe lot depends upon the size of the lot andshall be in accordance with Table 22.

Table 22 Sampling Plan

LotSize Nil) NZ2) (N,+Nz ) C\ C,

(I) (2) (3) (4) (5) (6)

Up to 300 8 8 0

301 to 500 13 13 26 0 2

501 to 1000 20 20 40 0 3

1 ODland above 32 32 64 I 4

I) Size of the fi.rst sample.2) Size of the second sample.

E-2.2 The meters shall be taken at randomfrom the lot. The procedure given in IS 4905may be adapted.

E-3 NUMBER OF TESTS AND CRITERIAFOR ACCEPTANCE

E-3.1 Test of No Load Condition andStarting Condition

A sample of N 1 meters selected according tocol 2 of Table 22 shall be tested for the abovetests. Any meter failing in anyone of thesetests shall be considered defective. If the

24

number of defectives found in the sample is lessthan or equal to C1, the lot shall be consideredto be conforming to these tests. If the number ofdefectives is greater than or equal to C2 , the lotshall be considered as not conforming to thesetests. If the number of defectives is between C1and C2, a further sample of N2 meters shall betaken according to col 3 of Table 22 andsubjected to these tests. If the number ofdefectives in two samples combined is less thanCz, the lot shall be considered as conforming tothese tests, otherwise rejected.

E-3.2 Tests of insulation resistance, ac voltagetests, test of power consumption, test of meterconstantJregistration, limits of error andinterpretation of test results and adjustment (ifrequired).

From the sample of meters which have beendrawn according to E-3.1 and those that havepassed all tests of E-3.1, a sample of 8 metersshall be tested, all of which shall pass forconformity to these tests. If any of the metersfails in any of these tests, the whole lot shall bedeclared not conforming to the requirements ofthese tests.

E-3.3 Tests for Repeatability of Error

Above tests shall be carried out on 3 samplesselected from above 8 meters under E-3.2 andshall be tested for repeatability of error testsseparately. If anyone of the meters fails thewhole lot shall be declared not conforming tothe requirements of these tests.

E-3.4 The lot shall be considered as conformingto this specification, if provisions ofE-3.1, E-3.2and E-3.3 are satisfied.

IS 14697 : 1999

ANNEXF( Clause 3.1.8)

DIRECTION AND SIGN OF REACTIVE POWER

EXPORTREACTIVEPOWER - v ---

IMPORT ACTIVEPOWER

EXPORTCTIVE

POWER

NOTES1 Ifthe upright line is taken as the voltage vector and a line is drawn to represent the current vector of a single-phase orbalanced three-phase system, this current vector will indicate the condition of the other quantities.

2 Reference of this diagram is the voltage vector V (fi.-..:ed on upright line).

3 The current vector/varies its direction according to the phase angle ¢ .4 The phase angle 4> between current/and voltage V is taken positive in the clockwise direction.

25

IS 14697 : 1999

ANNEXG(Foreword)

RECOMMENDATIONS FOR ADDITIONAL REQUIREMENTS

G-O ac Static energy meters, especially multi­functional multi-parameter (for example, three­vectors) meters may be provided withadditional facilities to cater to the needs ofspecific applications. Recommendations forsome such requirements are furnished below.The required additional facilities in the meterare to be agreed between the supplier and theuser. Besides the references made in foreword,reference is made to Technical Report No. III :1997 'Specification for common meter readinginstrument' issued by Central Board ofIrrigation and Power, New Delhi.

G-1 ADDITIONAL DEFINITIONS

G-l.1 Volt-Ampere Hour Meter (VAh Meter)

An instrument intended to measure apparentenergy by integrating apparent power withreference to time.

G-l.2 Static Volt-Ampere Hour Meter

A meter in which current and voltage act onsolid state (electronic) elements to produce anoutput pulse count proportional to volt-amperehour.

G-l.3 Demand Integration Period

The nominal duration of the consecutive equalintervals of time (30 minutes) used formaximum demand computing.

G-l.4 Indicated Maximum Demand

The highest value of the mean power (active,reactive or apparent) indicated by the maximumdemand register during successive equalintervals of time between one zero resetting ofthe maximum demand register and the next.

G-l.5 Time of Day (TOD) Meter

A multi-rate meter provided with a clock and anumber of energy/demand registers, eachoperative during specified time intervals asrequired for different tariffs for different timeof day.

G-l.6 Communication Port

The device used to input data to the meter or tooutput data from the meter.

G-l. 7 Meter Reading Instrument (MRI)

Hand held portable equipment for transferringdata to or from ac static electrical energymeters from or to the base computer station oran external peripheral.

G-l.8 Common Meter Reading Instrument(CMRI)

It is a meter reading instrument with necessaryaccessories which is capable of interrogatingwith various makes of ac static electricalenergy meters when loaded with thecorresponding meter specific software(s) calledmeter reading instrument programme(s).

G-2 QUANTITIES TO BE MEASURED ANDDISPLAYED

The meter shall be capable of measuring anddisplaying the following electrical quantities forpolyphase balanced or unbalanced loads, withinspecified accuracy limits.

G.2.1 Active energy import, active energyexport, reactive energy import, reactive energyexport, apparent energy, maximum demand(kVAlkW), cumulative maximum demand(kVAlkW), rising demand with elapsed time.

G-2.2 It should be possible to display variousinstantaneous quantities, for example phasewise details of kW, kVA and power factor,overall kVA, overall kW, overall power factor,frequency, count for number of MD resets, realtime and check for display segments, withinaccuracy limits agreed by the manufacturerand the user.

G-3 APPLICATION OF CURRENT ANDVOLTAGE TRANSFORMER RATIO

It is preferable for the meter to have facilitiesfor making the registration, taking in toaccount CT and VT ratios.

G-4 MD RESET

A meter provided with maximum demandregister shall have at least one of the followingMD resetting options:

a) Automatic reset at the end of a certainperiod predefined by the user (say at aspecific date of a month).

b) Resetting through a common hand heldunit capable of communicating with themeter with proper security.

c) Manual resetting arrangement withsealing facility.

G-5 MAXIMUM DEMAND INTEGRATIONPERIOD (DIP)

G-5.1 DIP can be set at either 30 minutes or15 minutes by the manufacturer's works. The

26

adjustment option shall be available in themeter not accessible by the user.

G-5.2 DIP may commence either at the time ofresetting the maximum demand or at the fixedintervals of the real time as agreed by the userand the manufacturer.

G-5.3 The rising demand with the elapsed timeshould be held in the memory in the event ofinterruption or switching off supply and itshould not become zero on such instances.

G-6 DISPLAY OF MAXIMUM DEMAND

The display of maximum demand in kVAfMVAikWIMW should have adequate resolution asper accuracy class of the active part of themeter at 20 percent of the load. In short, thedisplay of kVAikW should have more decimalpoints than the normal low resolution kWh/kVarh/kVAh display. For example, a Class 1.0meter may have 1 decimal point kWh display,but will require at least three decimal pointsfor kW/kVA display to record MD correctly at20 percent of the load.

G-7 GUIDE FOR kVAh MEASUREMENT

Generally two different measurementtechniques are adopted for YAh measurement,namely vector sum and arithmetic sumprinciples.

Vector sum volt-ampere is the vector sum ofactive energy and reactive energy in a 3-phasebalanced load or unbalanced circuit.

Arithmetic sum volt-ampere is the arithmeticalsum of the three products of line current andassociated phase voltages in a three-phasebalanced or unbalanced circuit.

In case of electromechanical meters, kVAh asmeasured by above principles, are generallydifferent. However, for static three parametermeters having high speed microprocessoradopting kVAh computation at very high rates,the vector sum value of kVAh tends to thearithmetic sum value in limiting case.Therefore, it is suggested to consider thatwherever, kVAh has appeared in thisspecification, it is the same as the vector sumvalue. Thereby, it becomes easier to check thekVAh accuracy by determining errors of kWhand kVarh meters only in terms of kWh andkVarh measurement standards.

In addition the computation error of vector sumis to be verified at a power factor common with inthe ranges Cos $ =0.5 lag to 1.0 and Sin $ =0.5lag to 1.0 lag (Cos $ = 0.866 lag to 0.00 lag). Thesuggested power factor is 0.5 lag or 0.866 lag. Itis determined by comparing the indicated kVAhwith the theoretical computed kVAh as obtainedfrom kWh and kVarh reference meters. Theallowable error limit is the vector sum of kWh

IS 14697 : 1999

and kVarh error limits. In case of threeparameter meter, it becomes convenient tocompute this kVAh from the kWh and kVarhreadings of the meter itself.

G-8 TIME OF DAY (TOD) REGISTERS

Depending on the requirement, up to sixdifferent registers for storing energies (active/reactive/apparent) and maximum demand(active/apparent) for different real time zones(TOD's) should be available. It should bepossible to redefine the time periods throughthe common hand held unit with propersecurity. The main control for this change shallbe available on the computer located at thebase station.

G-9 COMMUNICATION CAPABILITY

A meter irrespective of make should havefacilities for data transfer by a common handheld unit (common meter reading instrument)to/from a base station with proper security viaan optically isolated communication port usingserial communication.

Whenever required for summation, telemeteringor time synchronization purposes, requiredoutput should be provided.

G-IO TAMPER AND FRAUD MONITORING

The meter shall have the following specialfeatures of recording occurrences of abnorma­lities in order to monitor and to detect tamperand fraud against meter:

a) The meter should be capable ofrecording occurrences of a missingpotential and its restoration with dateand time of first such occurrences andlast restoration along with total numberand duration of such occurrences duringthe above period for all phases.

b) The meter should detect CT polarityreversal and record the same with dateand time of first such occurrences andlast restoration along with total numberand duration of such occurrences duringthe above period for all phases.

c) The meters for 3-wire applications shallindicate load unbalance between thephases over and above a specified value.

d) The meter shall record the occurrence Iand restoration of conditions ofabnormal magnetic field in its vicinity.

NOTES1 Abnormaljties and number of occurrences other thanabove can be mutually agreed upon between the userand the supplier.

2 Threshold values of electrical parameters (voltage'currenUpower factor) and the minimum duration ofsuch occurrences of abnormalities, are to be agreedbetween the user and the supplier.

27

IS 14697 : 1999

G-12 LOAD SURVEY CAPABILITY

3 All the above special features to mo"nitor/detect tampershould be available even in the absence of reference(common meter reading instrument) and down load thisdata into a base computer system (BeS) for generatingcomplete details. Necessary software for this purposeshall be provided by the meter manufacturer.

0.5 S± 5 minutes

0.2 S± 2 minutes

G-16 In view of varying nature of requirementof various utilities regarding registration ofreactive and apparent energy at leading powerfactors, there should be flexibility to meet theseneeds satisfactorily. For example reactiveenergy at leading power factor may beconsidered as zero or may be stored in aseparate register. Similarly apparent energy atleading power factor may be computedirrespective of the sign of the reactive energy Orequated to the active energy when the reactiveenergy is considered as zerO.

G-17 All the registers and other parametersshall be updated every second.

G-18 TIME ACCURACY

In the case of meters provided with real timeclock, facility for adjustment of real time shouldbe provided through common meter readinginstrument with proper security.

The uncertainty of setting initial time shallnot be more than ± 30 seconds from the IndianStandard time as maintained by NPL,New Delhi.

The maximum drift per annum permissible inthe real time clock shall be as follows:

G-19 SELF DIAGNOSTIC FEATURE

The meter shall have indications for unsatis­factory/non-functioning of the following:

a) Time and date, andb) All display segments.

G-20 MEASUREMENT OF HARMONICENERGTIPHASECURRENT

The meter shall be capable of measuring 50 Hzenergy and total energy (consisting of 50 Hzenergy and harmonic energy).

The capacity of measuring harmonic powerdepends on the sampling rate, the order ofwhich should be agreed upon by the user andthe supplier. Since the load has over-whelmingcontribution to harmonic power, as confirmedby analysis of various types of sourceslloads, itshall be sufficient for the user to determine theaccuracy of current measurement under thepresence of harmonic of 30 percent total harmo­nics distortion (THD), commensurate with theaccuracy class of the active part of the meter.

The display of various phase currents shall,therefore, be made (may be with the help ofexternal meter reading device) and shall beprovided with necessary resolution.

The requirements specified here are to bemutually agreed between user and supplier.

: For bulk consumerand energy audit

: For bulk consumersand energy audit

: For energy auditpurpose or specialpurposes

c) kVar export

d) kW or kVA export

The meter should be capable of storing in itsnon-volatile memory demand data for one ormore parameters specified below periodicallylogged at predefined intervals as agreed by thesupplier and the user:

a) kW or kVA demand: For all typesimport

b) kVar import

G-13 The display for kWh, kVarh and kVAhshould have facility for high resolution displayto facilitate testing with desired accuracywithin reasonable time. Alternatively thecommon meter reading instrument may havethis facility of reading the high resolutionregister of the meter for testing purpose.

G-14 In the absence of power supply, facility fordisplay or meter reading should be available.

G-15 While installing the meter, it should bepossible to check the correctness of connectionsof CT, VT to the meter with proper polarity.This may be available in the display of themeter for different ways the voltages andcurrents are injected. For this purpose, asuitable software for field diagnosis of meterconnections with the help of the meter andcommon meter reading instrument should besupplied.

G-ll DISPLAY PARAMETERS

By agreement between the manufacturer andthe user, it may be possible to have:

a) Auto display cycling facility for only essen­tial parameters (the persistence time andthe total cycle time having been specified).

b) Facility for display on demand for widerrange of parameters.

c) Facility for display on demand for moreranges of parameters on a common handheld unit (CMRI).

d) Facility for display of some securedparameters through BCS. When suchparameters are not desirable to bedisplayed at site by any of the above threemethods.

28

IS 14697 : 1999

ANNEXH( Clause 7.2)

STANDARD CONNECTION DIAGRAMS

This standard connections are given below. Thephase supply terminals are generally markedas 'R', 'Y' and 'B', though other conventions arealso acceptable if suitably marked on theterminal block cover. The neutral terminal is

marked as 'N'. It should be noted that eachindividual metered connection for independentload should be given an independent set ofphase and neutral connections directly from thesupply side.

t+--hL

R---"++-'Y --.J.j------+--+.I---x-­B--'---------'

LOAD

FIG. A THREE PHASE THREE WIRE METER WITH CURRENT TRANSFORMERS

R-"'--"-f'-"+-'y __L-+- I-_-+-...L-~

B----'--------'LOAD

FIG. B THREE PHASE THREE WIRE METER WITH CURRENT AND VOLTAGE TRANSFORMERS

29

- -_._-----------------

IS 14697 : 1999

LOAD

~~ -tf7 -tf7(1)iP(31 (4')q>t6 (;)~~9) ~~

\k I k I k I

"'="IrK ~I KR L K L

y ~$ ~ c~

~lB

@

FIG. C THREE PHASE FOUR WIRE METER WITH CURRENT TRANSFORMERS

R

Y

B

I' "\ I' 1"\ I' 1"\"- ,/ "- ',./ "- ./

(DC? 3 4 ~(6) ~<f(9 ~~

1: a a a \ \b b bk I k I k I

- B B E

lKA A A L K L K L

$ Q~0

LOAD

FIG. D THREE PHASE FOUR WIRE METER WITH CURRENT AND VOLTAGE TRANSFORMERS

30

IS 14697 : 1999

ANNEXJ( Clauses 9.6 and 12.17 )

TEST CIRCUIT DIAGRAM FOR THE TEST OF IMMUNITY TO EARTH/PHASE FAULT

fUT I f 1\ f 1\ f 1\\.~ \. .J \.~

- - -

~~/ I

I

~9~/~ tz 0

® aY .~

Meter t..t equlpment

Circuit to 5imu~t. earth fautt condltJon In phu_ 1.

varuo_ At the meter under ...t

1

l.iJ =1.9UnNormal condition

~ =1.9Un

31

L!l=1.9Un

Eantt fluK GondlUon

~=1.9Un

( Continued from second cover)

Technical Report No. 88 'Specification for ac static electrical energy meters', issued by CentralBoard ofIrrigation and Power (CBIP), New Delhi. First Revision, 1996.

Regarding test output the recommendation of CBIP Technical Report o. 88 first revision, 1996,has been adopted in this standard in view of various approved devices prevailing in the country_

The recommendations for additional requirement for multi parameter ac static energy metres forspecific applications are given in Annex G.

This edition 1.3 incorporates Amendment No. I (October 2003), Amendment No.2 (October 2004) andAmendment No. 3 (December 2004). Side bar indicates modification of the text as the result ofincorporation of the amendments.

For the pUl'pose of deciding whether a particular requirement of this standard is complied with,the final value, observed or calculated, expressing the result of a test, shall be rounded off inaccordance with IS 2 : 1960 'Rules for rounding off numerical values (revised)'. The number ofsignificant places retained in the rounded off value should be the same as that of the specifiedvalue in this standard.

Bureau of Indian Standards

BIS is a statutory institution established under the Bureau of Indian Standards Act, 1986 to promoteharmonious development of the activities of standardization, marking and quality certification of goods andattending to connected matters in the country.

Copyright

BlS has the copyright of all its publications. No part of these publications may be reproduced in any formwithout the prior permission in writing of BIS. This does not preclude the free use, in the course ofimplementing the standard, of necessary details, such as symbols and sizes, type or grade designations.Enquiries relating to copyright be addressed to the Director (publications), BIS.

Review of]ndian Standards

Amendments are issued to standards as the need arises on the basis of comments. Standards are alsoreviewed periodically; a standard along with amendments is reaffirmed when such review indicates that nochanges are needed; if the review indicates that changes are needed, it is taken up for revision. Users ofInwan Standards should ascertain that they are in possession of the latest amendments or edition byreferring to the latest issue of 'B]S Catalogue' and 'Standards: Monthly Additions'.

This Indian Standard has been developed from Doc: No. ETD 13 (5026).

Amendments Issued Since Publication

Amend No. Date of Issue

Amd. No.1 October 2003

Amd. No.2 October 2004

Amd. No.3 December 2004

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