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Application of Harmonic FiltersApplication of Harmonic Filters

JuneJune 20082008

Prepared by B. J. Park

PQ TECH INC.

2

IndexIndex

Design ConsiderationsUnderstanding Capacitors (Construction, Process, Capacitor Types, Tests)Filter ReactorsWhat is K factor?Surge ArrestorsSwitching CapacitorsGrounding versus UngroundingBanks Protections (Various Protection, Setting Philosophy)Harmonic Filter TypesBank DesignSteel Making Plant HarmonicsCase Study for Electrochemical Plant

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3

Harmonic Filter Design ConsiderationsHarmonic Filter Design Considerations

Various Nonlinear Loads Harmonic Voltage and or Current can cause damage to equipment Voltage Current Distortion Guide Line

Harmonic Filter Locations

300

400 75

125

150 150

23kV

380V Bus 1

380V Bus 2

4

Key Filter Design ConsiderationsKey Filter Design Considerations

Reactive Power RequirementsHarmonic LimitationsBackground HarmonicsHarmonic Filter Conditions (Ratings)System Transient, abnormal conditionsContingency Filter Conditions

3

5

Maximum and Minimum SizeMaximum and Minimum Size

The maximum bank sizea) Change in system voltage upon capacitor bank switching.b) Switchgear continuous current limitations.dV is limited in the range of 2%~3%, determined by load flow

The minimum bank sizea) Capacitor bank unbalance considerationsb) Fuse coordination

6

Construction of Capacitor ElementConstruction of Capacitor Element

ALUMINIUM FOIL5um Edge Fold

Hazed Polypropylene Film 11- 15um

4

7

Air Shower Booth to Access W/RAir Shower Booth to Access W/R

8

RollRoll WindingWinding ProcessProcess

5

9

Extended Foil SolderingExtended Foil Soldering

10

Container TIG WeldingContainer TIG Welding

6

11

Impregnation Impregnation FacilityFacility

12

ImpregnaImpregnanntt, , JarylecJarylec C101C101

Good Good performance performance in hin high temperatureigh temperatureLow Low dissipation factordissipation factorExcellent Excellent absorbing absorbing PDPD--characteristicscharacteristicsThe fluid is non chlorine The fluid is non chlorine biogradablebiogradable and contains no PCBs and contains no PCBs

CH2

CH3

CH2 CH2

CH3

Benzyltoluene 75% Dibenzyltoluene 25%

7

13

Impregnation, Under VacuumImpregnation, Under Vacuum 0.01 torrs0.01 torrs

ImpregnantFilling

Sealing

Drying

0

20

40

60

80

100

0 1 2 3 4

DAYS

TEM

P oC

5

14

RoutinRoutinee Test, Test, IEC 60871IEC 60871

8

15

PD Test in Shield Room @ 2.15*UnPD Test in Shield Room @ 2.15*Un

16

Routine Test, Routine Test, IEC 60871IEC 60871

Each capacitor unit undergoes the following:Leakage test at 60°C for 24 hoursPartial Discharge Test at 2.15 UnHV tests:

AC terminal to terminal at 18kV for 10 secAC terminal to case at 38kV for 10 sec

Capacitance and Dielectric loss angle at UnShort circuit discharge test at 1.7UnInternal discharge resistor test

9

17

All-film -Low dissipation, hazed, high energy density Folded foil – Good performance to the PD and transientsImpregnation - Dribble penetration, extra vacuum levels, long term filling.Container -1.5mm 430 grade stainless steel, can be supplied unpainted. TIG welding

Power Capacitor UnitsPower Capacitor Units

18

Harmonic Filter Harmonic Filter CapacitorCapacitors s

D

Film

FoilExtended Foil

DUE0 =

10

19

Between voltage gradient and failure rate, and assumed life can be described as

Assumed LifeVoltage Gradient

Failure rate

Where:L =Expected lifeN = Number of elementsλ = Failure rate (0.01%/year)Eo= Designed Voltage GradientE = Actual Voltage Gradientα = Constant for Voltage Gradient (α = 6 ~17)

Capacitor Life Expectancy Capacitor Life Expectancy

( )-α

Eo

EλNL ⎥

⎦

⎤⎢⎣

⎡=

20

Many connection, fuses, more hands, degrade insulation, costPossible to continuing service after few fuses brownUnit rating around 10kV

Internally Fused Capacitor UnitInternally Fused Capacitor Unit

11

21

Unit rating 15~25kV

Externally Fused Capacitor UnitExternally Fused Capacitor Unit

22

All strings must be separated / simple process / good joint foil electrodes at dielectric fault

FuselessFuseless Capacitor UnitCapacitor Unit

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23

Yes, but the is concern the oil contamination

Europe

Less

Lower

No(hazard)

Smaller

6P12S

Higher

Impossible

Fuseless

Yes, but the is concern the oil contamination

Europe / Asia

No

America / Asia

Higher

Higher

yes

Higher

6P 12S

Lower

Easy to find

Externally Fused

Less

Lower

No(hazard)

Smaller

12S 6P

Higher

Impossible

Internally Fused

Connection (example)

Replace cost

Visual check for faulty unit

Protection for terminal to case fault

Popular using Area

Cost of protection

Sensitivity of unbalance

Continuing service of unit at a roll faulty

Delta C by faulty roll

Features & Types

Types of Capacitor UnitTypes of Capacitor Unit

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Filter Capacitor Specification ExampleFilter Capacitor Specification ExampleRated voltage 9008 [V]Rated current 87.48 [A]Rated output 788 [kVAr]

Type All filmRated capacity 788 [kVAr]Rated capacitance 30.91 [uF]

Rated frequency 50 [Hz]Insulation level 30 [kVrms], 95 [kV BIL]Number of phase Single Phase

Number of bushing 2Dielectric Synthetic polypropylene filmElectrodes Fold/Laser cut aluminum foil Impregnate with Non-PCB dielectric fluid

Protection method Internally fusedPainting color Munsell No. 5Y7 / 1Painting method Vapor cure double layers Epoxy coated

Discharge device Built in resistorsDischarge time / unit <50V within 5 [min]Standards IEC60871-1, 60871-2, 60871-4

Case material Stainless Steel 1.6 [mm]Fixing hanger bracket 2 EA for both sideContinues allowable overvoltage 110 [%] Un

Maximum permissible kVAr 135 [%]Tolerance of capacitance -0 ~ +15 [%] at 25 [Ċ]

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25

Probability of 2Probability of 2ndnd failure for Each Typesfailure for Each Types

IEEE summer meeting 1997IEEE summer meeting 1997

[1]>[2] 2nd Failure in the Same group

[1]>[11] 2nd Failure in the another group

26

24

26

6.40

6.20

λ for [1]>[11]“Random”

% / year

0.0150.4Fuseless(Internal String)

132kV, 36 MVArY-Y connection5

0.0452.6Fuseless(conventional)

132kV, 36 MVArY-Y connection4

0.0100.26Internally fused 132kV, 36 MVArY-Y connection3

0.0220.57Externally fused 33 kV, 9 MVArY-Y connection2

0.0100.26Internally fused33 kV, 9 MVArY-Y connection1

Δc/c

%/ Year

λ for [1]>[2]“Avalanche”

% / yearCapacitor TypeBankCase

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Filter ReactorsFilter Reactors

Magnet wire is copper wire which has been coated (or enamelled) with a very thin layer of insulating material

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Filter ReactorsFilter Reactors

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10.1151.596Σ

0.0160.0000.00525

0.0340.0000.00823

0.0160.0000.00621

0.0440.0000.01119

0.0940.0000.01817

0.0810.0000.01915

0.1060.0010.02513

0.3400.0030.05311

0.1570.0020.0449

0.7900.0160.1277

3.5530.1420.3775

3.8880.4320.6573

1.0001.0001.0001I2 x h2I2Current (Pu)Harmonic

Ex)K factor = 6.34 PEC-R= 8% (Eddy current loss factor) Irms = 0.85 (pu)

2

2h

h

I hK

I= ∑

∑2

11

ECRrms

ECR

PIKP

−+=

+´

What is K factor?What is K factor?

IEEE C57.110IEEE C57.110--19861986

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Typical Air Core Dry Type ReactorTypical Air Core Dry Type Reactor

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Magnetic ClearanceMagnetic Clearance

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Filter Reactor Specification ExampleFilter Reactor Specification ExampleType Air Core, 6 [%] System Voltage 132 [kV]Rated Frequency 50 [Hz]Rated Inductance 59.0 [mH]Rated Current 262.43 [A]Insulation Level 275 / 650 [kV]Number of Phase Single PhaseTemperature Rise 60.5 [Ċ]Color Munsell No. 5Y7 / 1Standards IEC 289Frame and StructureReactors shall have mechanical and electrical strength and it shall be painted with Munsell No. 5Y7 / 1.Installation OutdoorCooling Air-cooled with natural convectionImpedance calculation of the bankZf for Fundamental Frequency, Xcf = 308.94 Ohm, Xlf = 18.54 Ohm, Zf = 290.4 OhmZ5 for 5th harmonic Frequency, Xc5 = 61.79 Ohm, Xl5 = 92.7 Ohm, Z5 = 30.91 Ohm TestsThe tests are carried out by manufacturer accordance with standard IEC 289.The reports are attached herein.Routine testsMeasurement of winding resistanceMeasurement of impedance at continuous currentSeparate source voltage withstand testInduced over voltage withstand test

Type testsTemperature rise testLightning impulse test

Marking IEC 289.16

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Surge ArrestorsSurge Arrestors

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To prevent capacitor failures at a breaker restrike or failure.

To limit the risk of repeated breaker restrikes.

To prolong the service life of the capacitors by limiting high overvoltages.

To serve as an ”insurance” against unforeseen resonance conditions which otherwise would lead to capacitor failures.

For overall limitation of transients related to capacitor bank switching which can be transferred further in the system and cause disturbances in sensitive equipment.

For upgrading of capacitors by preventing high overvoltages and/or for increasing the service voltage.

To serve as protection against lightning for capacitor banks connected to lines.

Using Surge ArrestorsUsing Surge Arrestors

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Arrestor PositioningArrestor Positioning

Continuous operating voltageRated voltageEnergy capability

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Arrestor PositioningArrestor Positioning

ExampleSystem voltage: 36 kVFault clearing time:10 s or lessSystem grounding: UngroundedCapacitor bank connection: Ungrounded wyeRated 3-phase power: 18 MVArDesired protective level : 2,4 p.u.

Summary of required arrester data for connection Phase-ground:Rated voltage: 33 kV or moreProtective level at 3kA: 64,7 kV or less (switching surge)Energy capability for capacitor discharges:2,8 kJ per kV rated voltage or more

Summary of required arrester data for connection Phase-neutral:Rated voltage: 33 kV or moreProtective level at 3kA: 69 kV or less (switching surge)Energy capability for capacitor discharges:3,2 kJ per kV rated voltage or more

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High duty-cycleMost circuit breakers and protective devices operate a few times in their entire life span.Switch for capacitor bank gets to operate every day, sometimes several operations per day.

Voltage spikeWhen capacitor switches do operate, they generate undesirable voltage surges, which if unmitigated, can cause problems in Power Quality to the users.

Re-strikeCommon concern for older switching technologies.

Switching Capacitor BanksSwitching Capacitor Banks

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Continuous currentungrounded neutral banks – 1.25 times the nominal currentgrounded neutral banks – 1.35 times the nominal currents

Inrush current during energizationNominal system voltageTransient recovery voltage during de-energization

Switches must be capable of withstanding inrush current

Ipk = Peak of Inrush current

Isc = available three phase fault currentI1 = capacitor bank current

141.1 III scpk ⋅=

The Key Considerations for SwitchgearThe Key Considerations for Switchgear

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Inrush current during back to back switching

Fs = system frequency in HzFt = frequency of transient in kHzLeq = total inductance between two banks in micro-henriesI1, I2 = being switched, already energized banks currents in AVLL = line to line voltage in kV

)()(1747

21

21

IILIIVI

eq

LLpk ⋅

⋅⋅=

)())()((5.9

21

21

IILIIVff

eq

LLst ⋅

+⋅=


20

39

Several hundred meters between overhead capacitor banks is usually an adequate separation distance to limit the inrush current to an acceptable level, but configurations where the banks are very close together may require inrush current limiting reactors.

When switching is done at nominal system voltage, the switch recovery voltage reaches 2.0 per unit for a grounded-wye-connected bank and 2.5 per unit for an ungrounded-wyebank.


Ec = Peak System Voltage

To = Beginning of Switching Opening

T1 = First Current Zero

T2 = 1/2 Cycle After First Current Zero

T3 = Switch Completely Opened

Switching Recovery Voltage

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The 6% inductor to the capacitive reactance has been widely usedThe 6% inductor to the capacitive reactance has been widely used , , to reduce the inrush current less than 5 times the nominal curreto reduce the inrush current less than 5 times the nominal currents nts

LCo1

=ω LC ZZ =× 06.0

ωω1,11

=Ω== CC

ZC

)(sin tZVi o

oo ω=

ω

ωω

ω ×=×

= 1.406.01

1o

ωω 06.0,06.0 =Ω== LLZL


21

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ITI CurveITI Curve

42

Synchronous Type Circuit BreakerSynchronous Type Circuit Breaker

P1 : Graphs

0.1825 0.1850 0.1875 0.1900 0.1925 0.1950 0.1975 0.2000 0.2025 0.2050

-200

-150

-100

-50

0

50

100

150

200

y

Ap

A

B

C

Switching Sequence_ Ungrounded Capacitor Banks

22

43


Case 19

0.160 0.180 0.200 0.220 0.240 0.260 0.280 0.300

-8.0

-6.0

-4.0

-2.0

0.0

2.0

4.0

6.0

8.0

y

step1-Ia step1-Ib step1-Ic

-300

-200

-100

0

100

200

300

y

Ap

Without Series ReactorWithout Series Reactor

44


With 6% Series ReactorWith 6% Series ReactorCase 19

0.160 0.180 0.200 0.220 0.240 0.260 0.280 0.300

-8.0

-6.0

-4.0

-2.0

0.0

2.0

4.0

6.0

8.0

y


-300

-200

-100

0

100

200

300

y

Ap

23

45

Conventional Circuit BreakerConventional Circuit Breaker

Case 19

0.160 0.180 0.200 0.220 0.240 0.260 0.280 0.300

-8.0

-6.0

-4.0

-2.0

0.0

2.0

4.0

6.0

8.0

y


-300

-200

-100

0

100

200

300

y

Ap

kA

kV

Without Series ReactorWithout Series Reactor

1.6 Per unit peak

65 kA peak

46

Conventional Circuit BreakerConventional Circuit Breaker

Case 19

0.160 0.180 0.200 0.220 0.240 0.260 0.280 0.300

-8.0

-6.0

-4.0

-2.0

0.0

2.0

4.0

6.0

8.0

y


-300

-200

-100

0

100

200

300

y

Ap

With 6% Series ReactorWith 6% Series Reactor

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47

General Control StrategyGeneral Control Strategy

grounded neutral, the three poles should close in succession with a time separation of 1/6 cycle (3.3 ms at 50 Hz or 2.8 ms at 60 Hz).

ungrounded neutral, two poles should close simultaneously at phase - phase voltage zero, and the last one 1/4 cycle later (5 ms at 50 Hz or 4.2 ms at 60 Hz).

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The advantages of the grounded wye compared to the ungrounded

Initial cost is lower, the neutral does not needed to full system BIL

Recovery voltages are reduced

Mechanical duties less severe for the structure

Low impedance path to ground for lighting gives self protection from surge

System & cap bank be grounded at 121kV above _ IEEE C37.99-2000

The disadvantages of the grounded wye compared to the ungrounded

Higher inrush current may occur in ground, it is needed NGR

Zero sequence harmonic current may draw to the ground

Usually makes current limiting fuses due to line to ground fault

Grounded Grounded vsvs UngroundedUngrounded

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SR Location and Insulation CostSR Location and Insulation Cost

2nd

0.0928[H]

A_curr

0.21 [ohm]

37.94[uF]

A_c

ap_u

0.01 [ohm]

0.01 [ohm]

0.01 [ohm]

1 [ohm]

A_rr

37.94[uF]

A_ca

p_d

2nd0.0928[H

]

B_curr

0.21 [ohm]

37.94[uF]

e_s

0.01 [ohm]

0.01 [ohm]

0.01 [ohm]

1 [ohm]

B_rr

37.94[uF]

B_ca

p_d

B_r

A_ng

B_n

g

Main : Graphs

0.00 0.10 0.20 0.30 0.40 0.50

0.0

2.5k

5.0k

7.5k

10.0k

12.5k

15.0k

17.5k

20.0k

y

A cap u B r

Main : Graphs

0.00 0.10 0.20 0.30 0.40 0.50

0.0 1.0k2.0k3.0k4.0k5.0k6.0k7.0k8.0k9.0k

10.0k

y

A_cap_d B_cap_d

Main : Graphs

0.00 0.10 0.20 0.30 0.40 0.50

0.0

2.5k

5.0k

7.5k

10.0k

12.5k

15.0k

17.5k

20.0ky

e_s A_cap_u

Reactor Bushing Potential

Capacitor Bushing Potential

Capacitor Bushing Potential

50

Unbalance detection means ;An internal element fails → voltage distribution & current flow change within a bank

Magnitude of changesexternally fused > internally fused

Purpose of the unbalance protection ;alarm or disconnect the entire capacitor bank when more than 10% over voltages across the healthy capacitors

More consideration required for ;Types of unbalance protectionOver currentsOver & under voltage

Protecting the Harmonic Filter BanksProtecting the Harmonic Filter Banks

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51

Neutral currentNeutral voltage

Current unbalance between neutralsPhase voltage unbalance

Voltage differenceCurrent unbalance in bridge connection

Types of Unbalance ProtectionTypes of Unbalance Protection

52

Sensing Neutral Current & VoltageSensing Neutral Current & Voltage

Neutral Current Neutral Voltage

Star Connection with Neutral Grounded Through a Current Transformer

Star Connection with Voltage Transformer Between Neutral and Ground

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Sensing dV & Current UnbalanceSensing dV & Current Unbalance

Voltage Difference Current Unbalance in Bridge Connection

Star Connection with Grounded Neutral and Voltage Transformers Connected in differential Measurement

Bridge Connection

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Sensing Unbalance Current & VoltageSensing Unbalance Current & Voltage

Current Unbalance BetweenNeutrals

Phase VoltageUnbalance

Double Star Connection with Ungrounded Neutral

Star Connection with Ungrounded Neutral and Voltage Transformers Connected in an Open Delta

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Summary of Capacitor Protection Methods Reference IEEE C37.99

Various schemes used, suitability depends on banks arrangements

Unbalance sensing with currents or voltage relays

Instantaneous relay action necessary to limit fault damage

Unbalance relayingOver current relayRack faultRack fault

To reduce inrush current required series reactor

Switched or fixed impedance in series with cap. BankInrush currentInrush current

Proper bank design Limit number of cap. Unit

Individual unit fuse Proper bank design

Discharge current from Discharge current from parallel connected unitparallel connected unit

Not suitable for unmanned substation for system over voltages

Visual inspection phase overvoltage relay

Continuous capacitor Continuous capacitor unit over voltageunit over voltage

Coordination provided by manufacture

Individual unit fuses (Expulsion or current limiting)

Over current due to unit Over current due to unit failurefailure

Grounded capacitor banks partially reduce surge voltageSurge arrestersSystem surgeSystem surge

Conventional methods applySupply breaker with OVR Power fusesBus faultBus fault

RemarksRemarksType of Protection Type of Protection Condition Condition

Summary of the Capacitor Banks ProtectionSummary of the Capacitor Banks Protection

56

1.01.0 1010 100100 1,0001,000 10,00010,000

Currents in amperes (Currents in amperes (r.m.sr.m.s.).)

1,0001,000

100100

1010

1.01.0

0.10.1

0.010.01

Time in SecondsTime in Seconds

Low probability Low probability of case ruptureof case rupture

High probability High probability of case ruptureof case rupture

Paper or paper Paper or paper film dielectricfilm dielectric

All film dielectricAll film dielectric

Case Volume 30,000CmCase Volume 30,000Cm33

Typical Case Rupture CurvesTypical Case Rupture Curves

29

57

Meters A, V, Var, MVA, MW, pf, Hz

SCADA - Var and Voltage control

Main BusSub Bus

TCCC

C / T * 3

Ground SW

Arresters

Capacitor S. W

60MVAr Capacitor Bank

4 Levels of Unbalance Protection

4 Levels of Instantaneous OCP

Reactor Over Load TD Protection

Under Currents TD protection

Measurements Last Trip Record

Remote Control for Trip & Closing

Reactors

NeutralResistor

ID for Faulty Phase

PT 3P

In- Sensitivity 0.005A

51Q, 51G, 51N - 3Vo, 3V1, 3V2, 3Io, 3I1, 3I2

Event Waveform Oscillograph

Breaker Failure Detection

Failure Target for Each phase Group

Meters and Indicators for Alarm

Battery Voltage Measurement

1 Serial ports1 Front, 3 rear- integrating

relays to SCADA

An example Protection SchemeAn example Protection Scheme

58

Conventional3CTs2P + 2PBalanced DY665kVAr, 96EAID faulty side, to be checked 48EA for a side

Advanced protection7 CTs (KEPCO)2P+2PBalanced SYDB665kVar, 96EAID the faulty phase,to be checked 32EA for

a phase

Advanced protection6 CTs2P+2PBalanced SYDB665kVar, 96EAID the faulty phase,to be checked 32EA for

a phase

Conventional1 CT2P(L) + 1P(R) Unbalanced DY887kVAr, 77EAFail only, to be checked 77EA for whole bank

Grounded YY (Single Y Double Br)Grounded YY (Single Y Double Br)Grounded YGrounded Y--Y (Double Y)Y (Double Y)

Ungrounded YY (Single Y Double Br) Ungrounded YY (Single Y Double Br) Ungrounded YUngrounded Y--Y (Double Y)Y (Double Y)

NGRNGR

Various ConfigurationsVarious Configurations

30

59

Filter Capacitor BankFilter Capacitor Bank

60

Overview of Capacitor Banks ProtectionOverview of Capacitor Banks Protection

Aim of Unbalance Protection (Alarm, Trip) Isolate faulty capacitor banks To prevent any of healthy units exposed to over than 110% of Un

Inherent unbalance current, Sufficient delay time to override external disturbances.

Overload Protection is to Protect from (Alarm, Trip) Overcurrent, harmonic current, OvervoltageThe trip stage is based on the IEEE Std. C37.99 IEC60871-1 inverse time characteristics

Overcurrent Earth Fault Protection, Should be Consider Switching inrush currentTime delay to clear the fuseSingle phase numerical type, standard inverse time

Overvoltage Protection is to Protect from the System Power Frequency Overvoltage

Undervoltage Protection, to trip the bank loss of system voltage, should be consideredReenergizing capacitor bank with a trapped chargeEnergizing a cap bank without parallel load through a previously unenergized transformerDelay time to override external faults

31

61

List of Relay UsedList of Relay Used

SWITCHSYNCE113ABBF25-POWPoint on Wave device7

KVGC 202ALSTOMF90-AVCAutomatic VoltageController6

KVFG 142AREVAF27=UVUnder-voltage Interlock Relay5

P 922SAREVAF27-UVUnder-voltage protection4

P 922SAREVAF59-OVOver-voltage protection3

SPAJ 160CABBF51 –UB &F49- OL

Capacitor Unbalance&Over-load protection2

P 123AREVAF50/51OCOver-current & EarthFault protection1

TypeManufacturerDesignationFunctionNo.

62

Protection Scheme & Coordination Plot Protection Scheme & Coordination Plot

Protection Scheme for 132kV 60MVAr

32

63

Features of Protection RelayFeatures of Protection Relay

Current Unbalance and OverCurrent Unbalance and Over--load Protection [ABB SPAJ 160C]load Protection [ABB SPAJ 160C]

Current Unbalance Relays (-F51UB)The relay receive the signal through neutral current transformer.Two stages of alarm provided. If any capacitor element fails, the relay shall set to

alarm (Stage 1) at appropriate value and to trip (Stage 2) the capacitor bank if the 110% rated voltage appears on any remaining units in the same unit.

Over-load Relays (-F49OL)Both inverse time current characteristic and definite time characteristic are provided.

Two stages of operation for alarm and tripping are also provided

64

OverOver--current and Earthcurrent and Earth--Fault Protection (F50/51OC) [AREVA P123]Fault Protection (F50/51OC) [AREVA P123]

Over-current Relays (-F50/51)Relays are of the three-single phase numerical type with both definite time and standard inverse time characteristic and with an independent measuring unit for each phase.

Earth fault Relays (-F50N/51N)Relays are single-phase numerical type with both definite time and standard inverse time characteristic and with an independent measuring unit for each phase


33

65

OverOver--voltage and Undervoltage and Under--voltage Protection [AREVA P 922S]voltage Protection [AREVA P 922S]

Over-voltage Relays (-F59OV)Time delay of both inverse time and definite characteristics types are provided. The relay should be provided for tripping off the capacitor bank in case of overvoltage condition occurring in the system such as due to sudden load loss.

Under-voltage Relays (-F27UV)Voltage Input is taken from existing voltage selection scheme / busbar VT. If there is no busbar VT then it is required that the voltage is taken from capacitor side VT, with is supplemented with a blocking logic as below.

The relay should be provided for tripping off the capacitor bank in case of temporary loss voltage such as during the line auto-reclosing, to prevent re-closing of capacitor bank before the capacitor is fully discharged.


66

Setting PhilosophySetting Philosophy

OverOver--current and Earth Fault (current and Earth Fault (--F5l OCEF) [AREVA P123]F5l OCEF) [AREVA P123]

The -F51 OCEF relay shall be set to operate as fast as possible in the occurrences of short circuit in the capacitor bank feeder since down-stream coordination are not required.

Characteristics of the -F51 OCEF relays will be determine from coordination studies. Both definite time (DT) characteristic and IDMT-Extremely Inverse Characteristic are used to protect the bank.

Time over-current relay (510C) - For a shunt capacitor bank, pickup setting 130% (IEEE std37.99-2000; the desirable minimum pickup is 135% of IN for grounded wye banks and 125% of IN for ungrounded banks) of rated current of the capacitor bank is proposed. Selection of time delay characteristic is based on coordination study. Both definite time and inverse time characteristic with time multiplier setting (TMS) higher than their respective overload characteristics is recommended.

Instantaneous over-current relay (50OC) - For shunt capacitor bank, pickup at least 1.15 times peak inrush to override inrush transient. (IEEE std. C37.99-2000 clause 7.2.3)

Time over-current relay (51 EF) - The capacitor bank is not grounded hence sensitive EF should be set to 20% pickup with the same operating time as OC elements to detect and to provide fast clearing for ground faults.

Instantaneous over-current relay (50EF) - Same as 51 OC or defeated if setting range not available.

34

67

Unbalance and Overload (Unbalance and Overload (--F5l UB/F5l UB/--F49OL) [ABB SPAJ160C]F49OL) [ABB SPAJ160C]

F49OL - This is a protection against over-voltages and harmonics current. Capacitor shall be able to carry continuous over-load current of 130% the rated current including due to harmonic and maximum voltage variations. The over-voltage trip start setting should be at 110% of capacitor bank rating, utilizing overload curve (at 1.1 pu). The alarm setting shall be at 110% of overload start setting with a time delay of 60 seconds and trip 115% with time delay 0.2seconds

F5l UB - The time delay of the unbalance relay trip should be minimized to reduce damage from an arcing fault within the bank structure and prevent exposure of the remaining capacitor units to over-voltage conditions beyond their permissible limits.

Setting shall be followed by Annex 4) which is analyzed that the unbalance neutral current, and based on over-voltage limit (per capacitor unit) when the internal fuse has blown up to three elements, the terminal voltage of the faulty unit capacitor is less than 103.1% of Un.Setting shall also be confirmed / compensated with neutral unbalance current after exercitation. (with measurement)


68


Characteristic of the overload curve is related to over-voltage characteristic of ANSI-1990 and IEC 60871-1. 1997 as tabulated below.

ANSI 1036-19926 cycles0.102.20

ANSI 1036-199215 cycles0.272.00

ANSI 1036-19921.00 s0.901.70

ANSI 1036-199215.0 s13.51.40

ANSI 1036-199260.0 s54.01.30

IEC 60871-1. 1997300 s2701.20

IEC 60871-1. 19971800 s16201.15

Standard durationTime (s)Overload

35

69


Under & OverUnder & Over--voltage (voltage (--F27UV/F27UV/--F59OV) [AREVA P922S]F59OV) [AREVA P922S]

F59OV - This protection as backup for the main protection. Inverse characteristic shall be coordinated with the allowable range as tabulated below. Alternatively, a definite time characteristic can be used with pickup at the maximum system voltage limit (+10%). Operating time shall be coordinated wilt the AVR setting.

1min1.30Voltage rise at light load5min1.20

System voltage regulation and fluctuations30min inevery 24h1.15

System voltage regulation and fluctuations8h in every 24h1.10

Highest average value during any period of capacitor service.Continues1.00

Power Frequency

Observation MaximumDuration

Voltage factor ×Un VrmsType

Capacitor allowable over-voltage range is as table 6 from IEC 60871-1. 1997 as follows

70

F27UV - Under voltage protection can be used to trip the capacitor bank and to block CB closing when its residual voltage is still high before being discharged after disconnection. The tripping function may be required if loss of system voltage. VT source should be taken from the busbar voltage selection to avoid blocking during normal closing if VT source from capacitor bank side.

Residual voltage allowable for capacitor discharging is less than 50Vdc from initial voltage of √2 of the rated voltage (Un). For this project, the bank is designed to reduce the residual voltage less then 50Vdc within 5 minutes. The manufacturer should provide discharge time to 50V in the instruction manual or rating plate.


36

71

Automatic Voltage Control (Automatic Voltage Control (--F90AVC)F90AVC)

System operations shall advise the bandwidth setting. The setting depends on the local system condition. Typical operating system voltage is between 1.0 to 1.05 p.u. The AVR setting for 132kv system is recommended to regulate the system voltage between the normal operating range. Recommended time delay to be set is 30s.

As per the operating experience we recommend the programmable timer setting, the daily closing time is at 08:00 and opening time is at 23:00, it shall be determined by the system operator.


72

Fault Level Calculation ExampleFault Level Calculation Example

37

73

Fault an AMPG Bus Under Peak LoadFault an AMPG Bus Under Peak Load

-79.625832.6TOTAL FAULT CURRENT (AMPS)NA

0.000.0TO SHUNT (AMPS)

999990.0049.35-82.404269.9AMP/OHM213275.00AMPG27588215

999990.0049.35-82.404269.9AMP/OHM113275.00AMPG27588215

5.91780.412.77-80.374319.4AMP/OHM213132.00PMJU13288175

5.91780.412.77-80.374319.4AMP/OHM113132.00PMJU13288175

4.20876.631.12-72.512692.9AMP/OHM213132.00TWSA13288137

4.20876.631.12-72.512692.9AMP/OHM113132.00TWSA13288137

5.91980.412.60-81.821661.4AMP/OHM213132.00KLJTI13288121

5.91980.412.60-81.821661.4AMP/OHM113132.00KLJTI13288121

APP X/RAN(Z+)/Z+/AN(I+)/I+/I/ZCKTAREAX-----------FROM--------------X

THREE PHASE FAULT

AT BUS 88120 AMPG132 132.00 Area 13 (kV L-G) V+: / 0.000/ 0.00THEV. R, X, X/R : POSITIVE 0.00360 0.0168 4.605

PSSE/E SHORT CIRCUIT OUTPUT MON, MAY 16 2005 17:16 HOME BUS is 881202007 PEAK LOAD CASE AMPG 132.00FAULTED BUS IS 88120 (AMPG132 132.00) 0 LEVELS AWAY

50 kA500kV40/50* kA275kV31.5 kA132kV

Short Circuit RatingVoltage Class TNB Planning criteria TNB Planning criteria

74

Construction of the Unit CapacitorConstruction of the Unit CapacitorConstruction of the Unit Capacitor

Rating : 9kV 1P 50Hz 591kvar, 23.18uF, 65.6A Construction : 6Series x 10Para (60 Rolls)

Eco : 13.91uF Discharge Resistor : 375kΩ x 6 series =2.25MΩ

Fuse : 0.4Φ Cupper Wire, Fuse Total length 20mΩ, Fuse operating Length 13.5mΩ

Unit Capacitor

Discharge Discharge ResistorResistor

13.91uF

Unbalance CalculationUnbalance Calculation

38

75

Unbalance current and overvoltage characteristics Unbalance current and overvoltage characteristics

99.612,971103.113,3141372,959357m3

99.812,888101.813,1501222,630214m2

99.912,901100.813,0201102,36993.8m1

100.012,912100.012,9121002,1522.76m0

Sound groupUnit % of Un

Sound groupunit VT-T[Vp]

Faulty Unit% of Un

Faulty unitVT-T[Vp]

Faulty Elementof Un

Faulty ElementGroup [Vp]NCT [Ap]No. of

faults

76

Typical Air Core Dry Type Reactor Typical Air Core Dry Type Reactor

39

77

Allowable Overload Current for ReactorAllowable Overload Current for Reactor

78

Typical Case Rupture Curve for ALL Film CapTypical Case Rupture Curve for ALL Film Cap

Typical case rupture curve for approximately 1800 cubic inchesTypical case rupture curve for approximately 1800 cubic inches-- case volume the dielectric case volume the dielectric material with Polypropylene film (ALL PP) quoted from IEEE Std. material with Polypropylene film (ALL PP) quoted from IEEE Std. 10361036--19921992

S’s typical clearing time of the internal fuse

40

79

Harmonic Filter TypesHarmonic Filter Types

80

Current Transformer2:2A 20VA

R S T

Configurations of Single Line Configurations of Single Line DwgDwg..

9 Series / phase

4 Parallel / phase

9s x 4p x 3 = 108 Cans

41

81

Key Rating FactorsKey Rating Factors

/(1 )c pV V α= −

/L cX Xα =

2( / ) (1/(1 ))L effXc V Q α= × −

/ 3P LV V=

2(1/ )L CX h X= ×

21/ hα =

L CX Xα= ×

(1/(1 ))cphase pV V α= × −/cunit cphaseV V Ns=

/( /(1 ))sr pV V α α= −

Three Phase Three Phase -- Single PhaseSingle Phase

VL Vsr

Vp

Vcphase

/(1 )cap effQ Q α= −

/capunit cap capQ Q N=

sr cap effQ Q - Q=

82

Harmonic Filter designHarmonic Filter design

2LLsys

effeff

kVX =

Q (Mvar)2

2 1C effhX X

h⎛ ⎞

= ⎜ ⎟−⎝ ⎠

2C

LXXh

=

Xeff is the effective reactance of the harmonic filter,Qeff is the effective reactive power (Mvar) of the harmonic filter,VLLsys is the nominal system line-to-line voltage,XC is the capacitive reactance of the harmonic filter capacitor at the fundamental frequency,XL is the inductive reactance of the harmonic filter reactor at the fundamental frequency,h is the harmonic number.

42

83

Numerical ExampleNumerical Example

A 30 MVA industrial load is supplied from a 34.5 kV bus. The three-phase fault level at the bus is 10.0 kA rms symmetrical. The load has a power factor of 0.85. It is desired that the power factor be raised to 0.95.The load is a source of harmonic current. The magnitude of the harmonic current suggests that the capacitor should be designed as a

harmonic filter.

Qeff (in kvar) = (multiplying factor)(load power in kilowatts)

Qeff = (0.291)(30 000 kVA)(.85) = 7420 kvar

84


Because of Phase shift of h component

43

85


86


44

87

Harmonic Current EstimationHarmonic Current Estimation

jXL Rs

-jXC Xs

Ih

88

Configurations of 132kV 60MVAr Configurations of 132kV 60MVAr (Ungrounded Double Y) Side view(Ungrounded Double Y) Side view

45

89

Configurations of 132kV 60MVAr Configurations of 132kV 60MVAr (Ungrounded Double Y) Front view(Ungrounded Double Y) Front view

90

Steel Making Plant HarmonicsSteel Making Plant Harmonics

Changing cycle by cycleInterharmonicsDesign Filter is not traditional

Interharmonics ->torsional and mechanical resonance

46

91


92

Steel Making FacilitiesSteel Making Facilities

Important Categories

Characteristic harmonicsDerive loads in the rolling mill

Non-characteristic harmonicsThird harmonic componentEven harmonic componentsShorter duration than conventional but important

InterharmonicsFluctuating EAF, CycloconverterShould be capable of measurement

Statistical characteristics of the harmonic levels

47

93

Steel Making FacilitiesSteel Making Facilities

Statistically evaluation for interharmonic12 cycles sample, bin size of 5HzCumulative probability distributionSpecific values can be determined the distortion levels

Vh95%

VTHD95%

Vh99%

VTHD99%

Ih95%

ITDD95%

Ih99%

ITDD99%

The harmonic filters should not magnify interharmonic components, resulting in excessive levels.

94


Example filter design for arc furnace installations.

48

95

Case Study for Electrochemical PlantCase Study for Electrochemical Plant

System Problems

The utility side transformer has excessive audio frequency noise and overheats.

Voltage THD on the 22 kV system is 7.7%, exceeding limits in IEEE Standard 519.

The rectifiers incur thyristor phase control malfunctions due to voltage sensing errors.Utility and customer capacitor banks incur over currents and excessive noise.

Complaints are generated from adjacent customers due to device malfunctions, and in particular, standstill conditions created at a precision electrical facility

Increasing System Reliability Using Series Tuned Increasing System Reliability Using Series Tuned Harmonic Filter Banks in a Chemical FacilityHarmonic Filter Banks in a Chemical Facility

16th Annual Power Quality Conference

October 25th -27th 2005

Baltimore Convention center

96


Utility Data

The normal Utility operating voltage is approximately 154 kV.

The Utility three-phase short circuit MVA is 1,400 MVA, with an X/R ratio of 10.

The 45 MVA supply transformer has a primary delta and secondary ungrounded wye winding arrangement, and a 5% impedance.

The incoming line distance from utility is indeed 0.75 km, composed with single core copper conductor 400 mm2.

22.9kV line has two sets of the capacitor banks 5MVAr, 6% SR

49

97


Ratings of Rectifier Converter

No.1 rectifier 5,810kW 3,210kVAr 6-pulse thyristor converter



No.4 rectifier 2,100kW 820kVAr 6-pulse thyristor converter

98

Case Study for Electrochemical PlantCase Study for Electrochemical PlantPlant System with 6% SL Capacitors

UTIL 1400MVA

D-Y154/22.9kV45/65MVAZ=5%

D-D22.9/6.6kV9MVA, 7%

D-D22.9/3.3kV5MVA, 7%

3.7MW950kVAr

3.7MW950kVAr

300kVA6.3Ohm

5MVAr22.9kV

CU500mm2

500mCU400mm2

750m

PCC

KPC23kVDSN

PKCOM23

300kVA6.3Ohm

5MVAr22.9kV

6% SeriesReactors

22.9kV1400kVAr

22.9kV1500kVAr

22.9kV900kVAr

D-Y22.9/0.22kV7.5MVA, 7.5%

D-Y22.9/0.22kV8.6MVA, 10%

D-Y22.9/0.22kV7.5MVA, 10%

D-Y22.9/0.22kV2.3MVA, 5.5%

5.8MW3.21MVAR

6.1MW4.91MVAR

5.8MW3.21MVAR

2.1MW0.821MVAR

UTIL 1400MVA

D-Y154/22.9kV45/65MVAZ=5%

D-D22.9/6.6kV9MVA, 7%

D-D22.9/3.3kV5MVA, 7%

3.7MW950kVAr

3.7MW950kVAr

300kVA6.3Ohm

5MVAr22.9kV

CU500mm2

500mCU400mm2

750m

PCC

KPC23kVDSN

PKCOM23

300kVA6.3Ohm

5MVAr22.9kV

6% SeriesReactors

22.9kV1400kVAr

22.9kV1500kVAr

22.9kV900kVAr

D-Y22.9/0.22kV7.5MVA, 7.5%

D-Y22.9/0.22kV8.6MVA, 10%

D-Y22.9/0.22kV7.5MVA, 10%

D-Y22.9/0.22kV2.3MVA, 5.5%

5.8MW3.21MVAR

6.1MW4.91MVAR

5.8MW3.21MVAR

2.1MW0.821MVAR

50

99


Impedance scan results and Harmonic spectrum

100

Passive FilterPassive Filter

Series Tuned Harmonic FilterHigh voltage Class : 50 < Q < 150Low voltage Class : 10 < Q < 50

LC1

C

L

R

ω

CL

RQ 1=

Cω1

Lω

R

FZ

)(ωFZ

51

101

Passive FilterPassive Filter

Damped High Passive Filter (2nd Order)

LC1

C

L

R

FZ

ω

Cω1

Lω

R

)(ωFZ

bR

bR

CRb

1

102

Without Filter: VTHD = 7.6%


Without Filter

52

103

Plant System with Harmonic Filter Banks


UTIL 1400MVAD-Y154/22.9kV45/65MVAZ=5%

D-D22.9/6.6kV9MVA, 7%

D-D22.9/3.3kV5MVA, 7%

3.7MW950kVAr

3.7MW950kVAr

300kVA6.3Ohm

5MVAr22.9kV

CU500mm500m

CU400mm750m

PCC

KPC23kV DSN

PKCOM23

300kVA6.3Ohm

5MVAr22.9kV

D-Y22.9/0.22kV7.5MVA, 7.5%

D-Y22.9/0.22kV8.6MVA, 10%

D-Y22.9/0.22kV7.5MVA, 10%

D-Y22.9/0.22kV2.3MVA, 5.5%

5.8MW3.21MVAR

6.1MW4.91MVAR

5.8MW3.21MVAR

2.1MW0.821MVAR 5th_1, 11th_High, 5th HF, 7th HF, 11th HF

60.7 6.05 15.6 15.4 8.2 mH

1006kVAr, 1934kVAr, 3162kVAr, 2028kVAr, 1485kVAr


D-D22.9/6.6kV9MVA, 7%

D-D22.9/3.3kV5MVA, 7%

3.7MW950kVAr

3.7MW950kVAr

300kVA6.3Ohm

5MVAr22.9kV

CU500mm500m

CU400mm750m

PCC

KPC23kV DSN

PKCOM23

300kVA6.3Ohm

5MVAr22.9kV

D-Y22.9/0.22kV7.5MVA, 7.5%

D-Y22.9/0.22kV8.6MVA, 10%

D-Y22.9/0.22kV7.5MVA, 10%

D-Y22.9/0.22kV2.3MVA, 5.5%

5.8MW3.21MVAR

6.1MW4.91MVAR

5.8MW3.21MVAR


60.7 6.05 15.6 15.4 8.2 mH


D-D22.9/6.6kV9MVA, 7%

D-D22.9/3.3kV5MVA, 7%

3.7MW950kVAr

3.7MW950kVAr

300kVA6.3Ohm

5MVAr22.9kV

CU500mm500m

CU400mm750m

PCC

KPC23kV DSN

PKCOM23

300kVA6.3Ohm

5MVAr22.9kV

D-Y22.9/0.22kV7.5MVA, 7.5%

D-Y22.9/0.22kV8.6MVA, 10%

D-Y22.9/0.22kV7.5MVA, 10%

D-Y22.9/0.22kV2.3MVA, 5.5%

5.8MW3.21MVAR

6.1MW4.91MVAR

5.8MW3.21MVAR


60.7 6.05 15.6 15.4 8.2 mH

1006kVAr, 1934kVAr, 3162kVAr, 2028kVAr, 1485kVAr

104


Fr. scan results & modeling data TR / Filter

53

105

Name Type Comp IRMS kW Losses kVar Losses VSUM%ADFL-5_1 Notch 59.589 4.134 1058.369 146.4%ADFL-11A 2nd Ord R 2.081 4.807

L 55.943 0.290 82.018C 55.990 110.5%

FL-5 Notch 95.393 1.204 490.719 116.6%FL-7 Notch 65.681 0.473 265.355 114.5%FL-11 Notch 46.222 0.201 94.608 111.9%


Filter data for design

106


5th, 7th, 11th, 11th Hi-pass filter currents

54

107


With Harmonic Filters

108

1.22.3K factor

0.7k0.76kCurrent Peak in Vp

19.1k20.9kVoltage Peak in Vp

471.9523.3Current Average in A

2.967.59~7.7Voltage Distortion %

6.73~7.0414.1~16.6Current Distortion %

0.980.88Power Factor

3,7009,870Power Q in kVAr

18,53018,440Power P in kW

18,90020,900Power S in kVA

Tuned Harmonic Filters6% SR CapacitorsDescription


Summary of before and after power characteristics

application of harmonic filters filter web.pdf · application of harmonic filters ... most circuit...

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