tutorial & seminar on power system protection & automation (2)

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Knowledge Sharing – Make it a way of LIFE

(KNOWLEDGE MANAGEMENT)

Contribution ByMr. Rajkumar Rastogi

(HOG-Protection & Testing) Mr. Lalit Kumar

(AM –Protection & testing )

Tutorial on Power System Protection & Tutorial on Power System Protection & Automation Automation

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Name of the program Name of the program attended attended

Tutorial/Seminar on Power Tutorial/Seminar on Power System Protection & AutomationSystem Protection & Automation

Program conducted by Program conducted by (Agency)(Agency)

Central Board of Irrigation & Central Board of Irrigation & Power Power

Duration of the programDuration of the program From:-25 To 28 February 2014From:-25 To 28 February 2014

Faculty/Eminent SpeakersFaculty/Eminent Speakers 1.Jay Gosalia ( Doble 1.Jay Gosalia ( Doble Engineering )Engineering )2.Dr. Richard Marenbach 2.Dr. Richard Marenbach (OMICRON)(OMICRON)3.BEIJING SIFANG AUTOMATION 3.BEIJING SIFANG AUTOMATION CO> LTDCO> LTD

Program ThemesProgram Themes 1. Distance Protection 1. Distance Protection 2. IEC618502. IEC618503. Ethernet Communications3. Ethernet Communications4. GOOSE & Process Bus4. GOOSE & Process Bus5. Engineering & Testing5. Engineering & Testing

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Key Takeaways - Quick Information Key Takeaways - Quick Information Overview of Protection and testing , PMUs, IEC-61850 Fundamental ,

Application & benefits in substation automation and protection

1) Distance protection basics 2) Introduction of PMUs 3) Overview of the IEC-61850 4) Object model and Ethernet communication 5) Goosing concept and usage 6) Station bus and process bus 7) Engineering and Testing

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Application of learning in participant’s area of Application of learning in participant’s area of responsibility:responsibility:

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Knowledge Sharing – Make it a way of LIFE 05/03/235

Transmission Line Protection

Distance Relays: - Introduction:

The impedance relays also called distance relays are employed to provide protection to transmission lines connected in a network as they are economic and possess several technical advantages.

They are comparatively simple to apply, operate with extremely high speed, and both primary and backup protection features are inherent in them.

They can be easily modified to work as unit schemes by coordinating them with power line carrier facilities and are suitable for high speed reclosing

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. The impedance relay is made to respond to the impedance between the relay location and the point where fault is incident.

The impedance is proportional to the distance to the fault, (hence the name 'distance relay') and is therefore independent of the fault current levels.

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Distance Relaying Principle:

A distance relay compares the currents and voltages at the relaying point with Current providing the operating torque and the voltage provides the restraining torque. In other words an impedance relay is a voltage restrained overcurrent relay.

The equation at the balance point in a simple impedance relay is K1V2 = K2I2 or V/I = K3 where K1, K2 and K3 are constants. In other words, the relay is on the verge of operation at a constant value of V/I ratio, which may be expressed as an impedance.

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Since the operating characteristics of the relay depend upon the ratio of voltage and current and the phase angle between them, their characteristics can be best represented on an R-X diagram where both V/I ratio and the phase angle can be plotted in terms of an impedance R+jX.

The power system impedance like fault impedance, power swings, loads etc. can also be plotted on the same R-X diagram. Therefore response of a particular relay during power swing, faults and other system disturbances can easily be assessed.

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Types of Distance Relays:

Impedance relay.

Reactance relay.

Mho relay.

Modified impedance relay.

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Impedance relay:

Characteristics of an impedance relay on R-X diagram is shown in fig.

Operation of the impedance relay is independent of the phase angle between V and I.

The operating characteristic is a circle with its center at the origin, and hence the relay is non-directional.

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Characteristic of Directional Impedance Relay: Characteristic of a directional impedance relay in the complex R-X phase is shown in fig.

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The directional unit of the relay causes separation of the regions of the relay characteristic shown in the figure by a line drawn perpendicular to the line impedance locus.

The net result is that tripping will occur only for points that are both within the circles and above the directional unit characteristic.

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The Reactance-type Distance Relay: Reactance relay measures V/I Sin0 (i.e. Z sin 0 - ). Whenever the reactance measured by the relay is less than the set value, the relay operates. The operating characteristic on R-X diagram is shown in fig

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The resistance component of impedance has no effect on the operation of reactance relay.

The relay responds solely to reactance component of impedance.

This relay is inherently non-directional.

The relay is most suitable to detect earth faults where the effect of arc resistance is appreciable.

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Mho relay:

This is a directional impedance relay, also known as admittance relay.

Its characteristic on R-X diagram is a circle whose circumference passes through the origin as illustrated in figure.

The relay is inherently directional.

It only operates for faults in the forward direction.

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Modified impedance relay: Also known as offset Mho relay whose characteristic encloses the origin on R-X diagram as shown in fig This offset mho relay has three main applications: -

Busbar zone backup

Carrier starting unit in distance/carrier blocking schemes.

Power Swing blocking.

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Main Features in Distance Scheme Distance schemes consist of the following major components:-

Starters.

Measuring units.

Timers Auxiliary relays

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Starters: -

The starting relay (or starter) initiates the distance scheme in the event of a fault within the required reach (more than zone-3).

Other functions of the starter are: -

Starting of timer relays for second and

third zones.

Starting of measuring elements.

The starters are generally of Mho or impedance type.

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Mho type starters: -

Measuring units for phase and earth faults can be either directional or non-directional as Mho starter is inherently directional.

With impedance type starters: - Measuring units have to be directional as impedance starters are non – directional.

The under impedance relay can be used in conjunction with the directional relay as starter which will then function similar to the Mho starter.

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Measuring units: - They are generally of a mho or reactance or a

combination of mho, reactance and resistance types.

Phase Fault Units:-

These measuring units are fed with line to line voltages (such as Vab, Vbc) and difference between line currents (Ia-Ib).

They measure the positive sequence impedance from the relay location to the fault point.

Three such relays respond correctly to all possible single line to ground faults line to line faults, double line to ground faults and 3-phase faults.

They however do not respond correctly to earth faults.

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Earth Fault Units: - These measuring units utilize line to neutral

voltage (Van, Vbn Vcn) and phase currents (Ia, Ib, Ic).

In order to make these units measure the positive sequence impedance correctly, a zero sequence current compensation is to be provided which is obtained by:

KN = (Z0-Z1)/ 3*Z1 where

Z1 = positive sequence impedance of line.

Z0 = Zero sequence impedance of line.

In the current circuit (1+KN) Ia will be fed for the above measurement.

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Timers: -

Timer relays when initiated by starters provide the time lag required for zones.

They also will be used for zone extension purpose whenever required.

Auxiliary relays: -

Distance scheme comprises of several auxiliary relays, which perform functions such as flag indications, trippings, signaling, alarm etc.

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Additional Features in distance schemes: -

Power Swing blocking relay VT fuse failure relay. Switch onto fault relay Fault locator Auto-reclosing scheme. Carrier communication scheme.

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Power Swing blocking: -

Distance relay which respond to balanced 3-phase changes in the impedance will be affected by power swings. Swings or oscillations occur following a system disturbance such as major load change or a dip in voltage due to delayed fault clearance. In case of fault, the transition from period of impedance locations (25 to 33% of starter impedance) to fault impedance (starter impedance) is sudden whereas during power swings it is slow. The PSB relays use this difference to block the tripping during swings.

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VT fuse failure relay: -

The distance relays being voltage restraint O/C relays, loss of voltage due to main PT fuse failure or inadvertent removal of fuse in one or more phases will cause the relay operation. The fuse failure relay will sense such condition by the presence of residual voltage without residual current and blocks the relay.

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Switch onto fault: -

When the line is switched on to a close by fault (say after line clear with earth switch closed), the voltage at the relaying point will be zero. Faults of this type will normally be cleared by backup zones.

The voltage applied to the relay is low and this condition occurring simultaneously with the operation of starter will cause instantaneous trip by SOTF relay.

This SOTF feature will be effective only for about 1-2 seconds after the line is charged.

Faults occurring after this time will be measured in the normal way.

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Fault locator: - It measures the distance between the relay location and fault location in terms of Z in Ohms, or length in KM or percentage of line length.

This relay gets same inputs as the distance relay (connected in series with one of the main relays). The measurement is initiated by trip signal from distance relays.

The fault locator gives the exact location of the fault, thereby reducing the time of restoration.

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Factors affecting distance relay operation:-

Fault resistance. Infeed effect. Branching-off effect. Load encroachment.

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Fault resistance:- Fault resistance has two components:-

Arc resistance. Ground resistance.

In a fault between phases, only arc resistance is involved.

For a fault at F, the actual line impedance

R + JX = ZL

Due to the presence of fault resistance, the impedance measured by the relay

R + JX + RF = ZR (where ZR > ZL).

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Fault arc resistance is given by Warrington's formula: Rarc = 8750 x L / I 1.4

where L = length of arc in ft

I = fault current in Amps

The arc resistance has little effect on accuracy of zone-1 unit as it operates instanteously before the arc can stretch appreciably except in case of short lines.

Reactance relays are therefore used for short lines where the fault resistance may be comparable with that of the protected lines and also for ground faults where the ground resistance is high.

The arc resistance will have greater impact on accuracy of

backup zones (time delayed) as the arc stretches appreciably.

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Infeed effect:-

The effect of intermediate current source between relay location and fault point is termed as infeed effect. Consider the sketch indicated in fig ---

A fault at F on the line BC is at a distance of Z1+Z2 for the relay at station A. But when current I2 flows from bus D, the impedance to the fault as seen by the relay at A is

Z1 + Z2 + Z2 x (I2/I1).

Thus the fault is seen by the relay as farther than what it really is, i.e. distance relay under reaches due to the infeed effect.

The effect of infeed becomes more pronounced with more interconnections at station B.

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Branching-off effect: -

A fault at F is at the distance of Z1+Z2 for the relay at station A. But when current I1 gets distributed as I2 & I3 at station B, the impedance to fault seen by the relay at station A will be (Z1 + I3/I1 * Z2) which is less than (Z1+Z2).

Then the fault is seen by the relay as nearer than what it really is i.e. distance relay overreaches due to branching-off effect. This overreaching tendency will cause the relay to loose its selectivity.

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Load encroachment: - ]

While protecting long lines the necessary reach may be so large that the minimum service impedance (or load impedance) falls within the region of the starter. This would result in tripping without there being any fault.

The two conditions i.e. operation at heavy load and short circuit differ by virtue of phase angle between voltage and current.

For the load impedance, the phase angle will be within +30 to -30 Deg. While during short circuits, the fault impedance has a phase angle of 60 to 80 deg. (i.e. line angle).

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Load encroachment problem is more pronounced in case of under impedance starters and gets lessened in case of mho, elliptical, lens etc, type of starters.

Relays with suitable characteristic on R-X diagram have to be carefully chosen to protect long and heavily loaded lines, and this becomes easily possible with microprocessor based numerical relays.

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Non-switched scheme vs switched scheme: -

In an ideal Non-switched scheme, there will be 6 starters, 3 for phase faults and 3 for ground faults.

There will be independent measuring units for both phase faults and earth fault for each phase, for all three zones, totaling to 18 units.

This scheme is faster and more accurate but is costly.

In the switched scheme, only one measuring unit will be used for all types of faults

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This single measuring unit is switched to the correct fault loop impedance by switching-in the respective voltages and currents by the starter.

The reach of the measuring element gets extended to zone-2 and zone-3 after the elapse of corresponding timings through zone extension process.

Switched scheme is relatively slow in operation and has the risk of total scheme failure in the event of failure of the only one measuring unit available.

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Zone extension schemes: - As a via media between non-switched and switched schemes, there are schemes with zone extension facility (such as EE make MM3V & MR3V relays).

These schemes consists of 3 measuring units for phase faults and 3 measuring units for earth faults (apart from 3 starters).

The reach of the measuring unit gets extended to zone-2 and zone-3 after elapse of corresponding timings through a zone extension process.

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Other Operating Characteristics:

Earlier when electromagnetic relays were in use, the characteristics involving straight lines and /or circles on R-X diagram were only possible.

With the advent of static relays, microprocessor based relays and presently of numerical relays, any desired/required-operating characteristic is possible giving wider choice for selection of relays. Infact there are relays, which can be programmed remotely.

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Application of distance relays: Since the distance relays are fed from the secondaries of line CTs and bus PTs/line CVTs, the line parameters are to be converted into secondary values to set the relay as per requirements. Zsecy = Zpri/Impedance ratio (where Impedance ratio = P.T.Ratio/C.T.Ratio) Hence any changes in C.T .ratio has to be effected along with revision of relay settings only.

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To ensure proper coordination between distance relays in power system, it is customary to choose relay ohmic setting as follows: - ------------------------------------------------------------------------- S.No. Zones Reactance Time ------------------------------------------------------------------------- 1. Zone-1 80% of ZL Instantaneous (no intentional time delay). 2. Zone-2 100% of ZL + 40-50% 0.3 to 0.4 of ZSL seconds 3. Zone-3 100% of ZL + 120% 0.6 to 0.8 of ZSL seconds 4. Zone-4 100% of ZL + 120% 0.9 to 1.5 of ZLL seconds.

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3-ZONE TIME- DISTANCE CHARACTERISTIC

Z3t3 Z2t2 Z1t1

A B C t1 Z1 t2

Z2 t3Z3

REACH TIME

ZONE-1: 0.8 X ZL INS (<100ms)

ZONE-2: ZL + 50% OF ADJACENT LINE 0.3-0.4sec

ZONE-3: ZL + 110% OF ADJACENT LINE 0.6-0.7sec

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where ZL = Positive sequence impedance of line to be protected. ZSL = Positive sequence impedance of adjacent shortest line. ZLL = Positive sequence impedance of adjacent longest line. Note: Where a three zone relay only is available, the

zone 3 will be set to cover the adjacent longest line.

The zonal timings will be carefully selected to properly grade with the relays on all the feeders . emanating from the adjacent bus

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Norms of protection adopted for transmission lines in A.P.System:- 132 KV Lines: - A switched type distance scheme supplemented by

three numbers directional O/L relays and 1 No. directional E/L relay.

220 KV Lines: - Two Distance Schemes: - Main-I: - Non-switched scheme fed from bus PT. Main-II: - A switched scheme fed from line CVT. .

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A provision is generally made for the changeover of voltage supply for the distance schemes from the bus PT to line CVT and vice-versa

Each distance scheme is fed from independent CT

secondary cores. 400 KV Lines:- Two Distance Schemes:- Main-I:- Non-switched or Numerical distance schemes Main-II:- Non-switched or Numerical distance schemes

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IEC 61850

IEC61850 is beyond just the protocol for substation automation , it also provides common addresses more of what is required for interoperability of intelligent electronic devices (IEDs) .

•Standardized object models and naming conventions•Standardized meaning of data•Standardized services and device behavior models•Self-describing devices•Common configuration language•Profiles for:–Control/SCADA–Protection messaging–Transducers and I/O


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•IEC61850-enabled IEDs get digitalized power grid condition data via process bus and merge units•IEDs communicate with each other using substation buses•Legacy devices use IEC61850 wrapper


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Process Bus


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Object model and Ethernet communication

Object & class :-

A class is a template for the creation of objects, the description of one or more objects with the same definitions for information and behavior.

An object is defined as an instance of a class .Objects represent information and behavior :–properties (or components, attributes)

• Data that describe an object–services (or methods, and events)

• Methods are things you can tell the object todo• Events are things the object does


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Function Definitions

The functional elements are the smallest parts of a function that canexchange data.

Functions in the substation are performed by the protection, control,monitoring and recording system . These functional elements in IEC61850 are called Logical Nodes .

Logical Node Groups :

System Logical Nodes LN Group: L

1)Logical Nodes for protection functions LN Group: P2)Protection related functions LN Group: R3)Control LN Group: C4)Interfacing and archiving LN Group: I5)Automatic control LN Group: A


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6) Metering and measurement LN Group: M7) Sensors and monitoring LN Group: S8) Switchgear LN Group: X9) Instrument transformers LN Group: T10) Power transformers LN Group: Y

Common data classes for measurant information

•Measured value (MV)•Complex measured value (CMV)•Sequence (SEQ)•Differential measurements Name: MDIF•Measurement Name: MMXU

Example

MMXU1.A.phsB.cVal.mag.f


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Ethernet communication

Ethernet devices attach to a common medium that provides a path along which the electronic signals will travel:- historically, this medium has been coaxial copper cable- more commonly a twisted pair -fiber optic cabling

Segment - a single shared medium as an Ethernet segment. Nodes - devices that attach to that segment are stations or nodes. Frame - The nodes communicate in short messages called frames, which are variably sized chunks of information


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Transmission Medium :

RS 232 - 9/25 pin D connectorEIA 232 - Maximum data rate 20kb/s-Maximum distance 50 feet

RS 485 - 2/4 conductorsEIA 485 - Maximum data rate 10Mb/s-Maximum distance 4000 feet

Optical fiber - Immunity to electrical interference-Advantages in distance and speed

Ethernet - 100 Mbps instead of few 10 kbps

Possible application areas in NDPL other than Possible application areas in NDPL other than participant’s area:participant’s area:

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Communication Structure Comparison between legacy and Ethernet


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Goosing concept and usage

GOOSE messages are one of the key feature of IEC 61850

GOOSE - Generic Object Oriented Substation Event

It supports the exchange of a wide range of possible common data organized by a DATA-SET.

GOOSE message :- GOOSE messages shall continue to send themessage with a long cycle time, even if no status/value change hasoccurred.

• This ensures that devices that have been activated recently will know thecurrent status values of their peer devices.


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Performances of GOOSE Massage :-


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Station bus and process bus


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Engineering and Testing

Engineering Process Requirements

• Requires the implementation of anengineering process based on:

– Knowledge of the problem domain– Knowledge of the state-of-the-arttechnology– Utility standards– Industry standards– Object-oriented design– State-of-the-art tools


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Challenges• Differences in the models implementedby different suppliers• Settings are not implemented• Programmable Scheme Logic modeling• Distributed functions modeling• HMI modeling• Testing related modeling issues

Benefits• Quite significant• Reduce the costs for system design• Improve factory and site acceptancetesting• Improve the maintenance process• Improve the overall quality of thesubstation automation system


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61850 Provides

1)Substation Configuration Language2)SCL Components a) Substation section: b) b) Communication section c) IED section d) LNType section3) SCL Files .SSD for System Specification Description. .ICD for IED Capability Description. .CID for Configured IED Description.


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Benefits

• Reduction of wiring costs• More flexible programming is independent of wiring• Reliability: Link status known before use.• New capabilities not cost-effective with hardwired systems.• Higher performance with more data.• Speed: 100 Mbps instead of few 10 kbps• Peer-to-peer: No extra hardware• Conditional report instead of polling• IP (Internet Protocol) routing• Independent of operating systems andprogramming languages• Independent of middleware• Independent of communication systems• Independent of vendor (multi-vendorsupport)


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IntroductionIntroduction

• Classical Definition of a PhasorClassical Definition of a Phasor– A pure sinusoidal waveform can be

represented by a unique complex number known as a ‘phasor’.• A sinusoidal signalA sinusoidal signal

• The phasor representation of this sinusoid is The phasor representation of this sinusoid is given bygiven by

71

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• Classical Definition of a PhasorClassical Definition of a Phasor– The RMS cosine-reference voltage and

current phasors are.

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(a) Sinusoidal signal (b) Phasor representation

•Classical Definition of a Phasor

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• Classical Definition of a PhasorClassical Definition of a Phasor– If the sinusoid is not a pure sine wave, the

phasor is assumed to represent its fundamental frequency component.

– The most commonly used method of calculating phasors from sampled data is that of Discrete Fourier Transform (DFT).

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• Important of the Phasor MeasurementImportant of the Phasor Measurement

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• Important of the Phasor MeasurementImportant of the Phasor Measurement

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• Modern EMS systems started from 1965Modern EMS systems started from 1965– Data refresh rate is around 2 to 5 seconds– Measurement signals are not synchronized– People relies upon power flow and state

estimation to estimate the angles among buses.– It is an offline estimation and the results are not

reliable.

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• Modern phasor measurement systems can trace Modern phasor measurement systems can trace origin to the development of the Symmetrical origin to the development of the Symmetrical Component Distance Relay (SCDR) in the early Component Distance Relay (SCDR) in the early 1970s.1970s.

• In early 1980s, measurement system started using In early 1980s, measurement system started using GPS to synchronize the sampling clocks, which GPS to synchronize the sampling clocks, which offering a common reference.offering a common reference.

• The first experimental PMUs were developed at The first experimental PMUs were developed at Virginia Tech in 1988, and Macrodyne built the Virginia Tech in 1988, and Macrodyne built the first PMU in 1992.first PMU in 1992.

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• The modern PMUs use one pulse per second The modern PMUs use one pulse per second signals provided by the GPS satellite signals provided by the GPS satellite receivers.receivers.– The accuracy of the GPS timing pulse is better

than 1 µs.– For a 60 Hz system corresponds to about 0.02

degrees.– Current PMU records data at the rate of 30

samples per second (This number can be adjusted).

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• Functional block diagram of the elements in Functional block diagram of the elements in a PMUa PMU..

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PMU and Smart Grid DevelopmentPMU and Smart Grid Development

• The electrical power system is one of the most The electrical power system is one of the most sophisticated man-made infrastructures. sophisticated man-made infrastructures.

• While the power system is a technological While the power system is a technological marvel, it is also reaching the limit of its ability to marvel, it is also reaching the limit of its ability to meet the nation's electricity needs.meet the nation's electricity needs.

• The modernization of the electricity The modernization of the electricity infrastructure leads to the concept of smart grid.infrastructure leads to the concept of smart grid.

• The smart grid as defined here is based upon the The smart grid as defined here is based upon the description found in the Energy Independence description found in the Energy Independence and Security Act 2007.and Security Act 2007.

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PMU and Smart Grid DevelopmentPMU and Smart Grid Development

• The term “Smart Gird” refers to a modernization The term “Smart Gird” refers to a modernization of the electricity delivery system so that it of the electricity delivery system so that it monitors, protect, and automatically optimizes monitors, protect, and automatically optimizes the operation of its interconnected elements.the operation of its interconnected elements.

• In general, a comprehensive smart grid design In general, a comprehensive smart grid design should take holistic approaches and cover both should take holistic approaches and cover both top-down and bottom-up approaches. top-down and bottom-up approaches.

• Many smart grid related activities have been Many smart grid related activities have been carried out all over the world. carried out all over the world.

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Desired Features of Smart GridDesired Features of Smart Grid

• Advanced monitoring, control, and demand Advanced monitoring, control, and demand management.management.

• Advanced components & operating concepts.Advanced components & operating concepts.• Robust modeling & simulation tools.Robust modeling & simulation tools.• Seamless interconnection of low environmental Seamless interconnection of low environmental

impact new generation technologies.impact new generation technologies.• Standardized architecture & secure Standardized architecture & secure

communication standards.communication standards.

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Potential Areas of Smart Grid Development and Potential Areas of Smart Grid Development and ApplicationsApplications

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PMU for Wide Area Monitoring and ControlPMU for Wide Area Monitoring and Control

• Deployment of Phasor Measurement Unit Deployment of Phasor Measurement Unit (PMU)(PMU)– In 2007, the organization of U.S Department of Energy

(DOE) and the North American Electric Reliability Corporation (NERC), along with involved electric utility companies and other organizations, formed the North American SynchroPhasor Initiative (NASPI)

– With funding from The American Recovery and Reinvestment Act of 2009, several smart investment grant and demonstration projects have been awarded to advance the synchrophsor technology.

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• Deployment of Phasor Measurement Unit Deployment of Phasor Measurement Unit (PMU)(PMU)

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• Potential PMU ApplicationsPotential PMU Applications• Wide-Area Visualization and Monitoring;Wide-Area Visualization and Monitoring;• Angle and Frequency Monitoring;Angle and Frequency Monitoring;• Interarea Oscillation Detection & Analysis;Interarea Oscillation Detection & Analysis;• Proximity to Voltage Collapse;Proximity to Voltage Collapse;• State Estimation;State Estimation;• Fast Frequency Regulation;Fast Frequency Regulation;• Transmission Fault Location Estimation;Transmission Fault Location Estimation;• Dynamic Model Validation.Dynamic Model Validation.

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• Though the above applications are from the view Though the above applications are from the view of ISO, the PMUs-based applications also benefit of ISO, the PMUs-based applications also benefit generator owners and other market participants. generator owners and other market participants.

• PMUs are able to continuously record several PMUs are able to continuously record several different signals which are the requirements of different signals which are the requirements of ancillary services like spinning reserve, frequency ancillary services like spinning reserve, frequency control and voltage control. control and voltage control.

• Once the infrastructure is permanently installed Once the infrastructure is permanently installed at the power plant, the online tests such as voltage at the power plant, the online tests such as voltage step-change can be easily applied and recorded.step-change can be easily applied and recorded.

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Sample PMU ApplicationsSample PMU Applications

• PMU applications in CAISO: PMU applications in CAISO: Wide area Wide area visualization and monitoringvisualization and monitoring

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Source: EPG

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• Recording of Actual EventRecording of Actual Event

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• Comparison between Actual response and Comparison between Actual response and Simulation ResultsSimulation Results

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WSCC (WECC) System Blackout on August 10, 1996

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• State EstimationState Estimation– State estimation techniques were developed in 1970s

• Obtain an approximation to averaged system state from Obtain an approximation to averaged system state from scanned data (seconds to minutes) scanned data (seconds to minutes)

• It is referred as “Static State Estimates”.It is referred as “Static State Estimates”.– PMUs enable synchronized phasor measurement bus

voltages & currents.• Make significant improvement on state estimation or state Make significant improvement on state estimation or state

measurement applicationsmeasurement applications• Install PMU in the system could be a smart move to improve Install PMU in the system could be a smart move to improve

the accuracy and efficiency of state estimation.the accuracy and efficiency of state estimation.

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•PMU Based On-Line generator parameter identification system.

. . . . .

GPS

Ethernet

PMU

PMU

PMU

hp Workstation i2000

hp Workstation i2000

Phasor Data Concentrator

EMS Database

ApplicationsCommunication StandardsIEEE C37.118.2IEC 61850-90-5ICCP

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•PMU Based On-Line generator response and parameter identification system.

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Original System Reduced System

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•PMU Based On-Line generator response and parameter identification system.• The Reliability Standards relate to generator model The Reliability Standards relate to generator model

verification are:verification are:• MOD-026-1 — Verification of Models and Data for Generator MOD-026-1 — Verification of Models and Data for Generator

Excitation System FunctionsExcitation System Functions• MOD-027-1 — Verification of Generator Unit Frequency MOD-027-1 — Verification of Generator Unit Frequency

ResponseResponse• Once these Reliability Standards are approved, the Once these Reliability Standards are approved, the

standards become mandatory and enforceable standards become mandatory and enforceable requirementsrequirements

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•Fault Location in the Transmission Network.

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Relevant PMU StandardsRelevant PMU Standards

• C37.111-1999C37.111-1999– A general transient data recording file format standard

• C37.118.1-2011C37.118.1-2011– Covers synchrophasor measurements for power systems– Adds frequency & rate of change of frequency

(ROCOF) and dynamic operation

• C37.118.2-2011C37.118.2-2011– Defines real-time synchronized phasor measurement

data exchange method

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Conclusion and DiscussionConclusion and Discussion

• PMU is a matured technology.PMU is a matured technology.• In addition to the original intended applications In addition to the original intended applications

on “Phasor Measurement”, PMUs offer on “Phasor Measurement”, PMUs offer attractive options for improving protection and attractive options for improving protection and control actions on modern power systems. control actions on modern power systems.

• Future power systems will have to face more Future power systems will have to face more stressful regimes; improved protection and stressful regimes; improved protection and control offered by the wide area measurement control offered by the wide area measurement systems based on PMUs will become even more systems based on PMUs will become even more important.important.

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SEEKH Session DetailsSEEKH Session DetailsDate of SEEKH Session:

No. of People Participated:

Any new action initiated or new idea generated (SHINE) because of SEEKH Session:

KM INDEX POINT:

Microsoft Word Document

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For any Query regarding this SHIKSHA document For any Query regarding this SHIKSHA document please contact me atplease contact me at

Ph/Mob:Ph/Mob:Email:Email:

Thank YouThank You

tutorial & seminar on power system protection & automation (2)

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