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Synchronized Phasor Measurement

Jassim Al Hamad

SEL Middle East

What Is a ‘Synchrophasor’?A synchrophasor is a phasor measurement with respect to an absolute time reference. With this measurement we can determine the absolute phase relationship between phase quantities at different locations on the power system.

Synchrophasors Provide a “Snapshot”of the Power System

Synchrophasors Are for Operators What Fault Location Is for Linemen

Photos courtesy of Niagara Mohawk, a National Grid Company

Why Do Synchrophasors Matter Anyway?

Normal Nighttime View

Long Island

New York State

Darkness Gets Attention

Long Island

New York State

Single Quantity Disaster PredictorPhase Angle Separation

Synchrophasor Applications

Model Creation and Validation

System State Measurement and Visualization

Event Prediction

Post Disturbance Analysis

System Size and Application Determines Communications Requirements

V8

V6

V9

V7

V5

V4

V3

V1

V2

I5

I7

I6

I4

I10

I8

I13I9

I14I11

I12

I1

I2I3

Uncertainty Tolerance

Synchrophasor Measurements

V8

V6

V9

V7

V5

V4

V3

V1

V2

I5

I7

I6

I4

I10

I8

I13I9

I14I11

I12

I1

I2I3

Transmission Line Separated Into Lumped Resistive

and Reactive Components

V1 V2

I1 I2R L

Y/2 Y/2

Y = [ (i1 - i2) / (v1 + v2) ] • 2

C = Im (Y) / 2πƒ

Z = (v12 - v2

2) / (i1v2 + i2v1)

R = Re (Z)L = Im (Z) / 2πƒ

Solving for Line Constants

V1 V2

I1 I2R L

Y/2 Y/2

Synchronize Data With <METER PM>

Voltage Phasors DetermineSystem Power Flow

( )BAL

BA sinX

EEP δ−δ⋅⋅

=

XL

A B

AAE δ∠ BBE δ∠

( )[ ]BBAAL

B EcosEXEQ −δ−δ⋅⋅=

P,Q

State Estimation Process

V1∠δ1

jXL

V2∠δ2

rrore (V, h

QPVV

State

tsMeasuremen

+θ=

⎥⎥⎥⎥⎥

⎦

⎤

⎢⎢⎢⎢⎢

⎣

⎡

321

321

)

12

12

2

1

10 minutes

State Estimation Takes Data From SCADA System

EMSSystem

Xdcr XdcrXdcr Xdcr

RTU

StateEstimation

f(P, Q, |V|) = δ (estimate)

~10 minutes

Faster State EstimationWith Synchronized Measurements

V1∠δ1

jXL

V2∠δ2

rrore (V, h

QPVV

State

tsMeasuremen

+θ=

⎥⎥⎥⎥⎥

⎦

⎤

⎢⎢⎢⎢⎢

⎣

⎡

321

321

)

12

12

2

1

{

321State

tsMeasuremen

(V, h

VV

)

2

1

2

1

θ=

⎥⎥⎥⎥

⎦

⎤

⎢⎢⎢⎢

⎣

⎡δδ

10 minutes 1 second!

Improvements to State Estimation Using Synchrophasors

0

0.0005

0.001

0.0015

0.002

0.0025

0.003

0.0035

0.004

0.0045

0.005

0 10 20 30 PMU only

Percentage of Buses with PMUs

Stan

dard

Dev

iatio

nStandard deviation of |V|

Standard deviation of Φ

Critical Clearing Timefor a Three-Phase Fault

0 50 100 1500

0.5

1.0

1.5

δcSystem Load Angle (deg)

Pm

Pe

A2

A1

δ0

Rea

l Pow

er (W

atts

)

Stability depends on prefault load angle and fault duration


System Is Stable for a 200 ms Fault

0 4 8 12

1.04

1.00

0.96M

achi

neA

ngle

pu


Time (s)

Machine Angle

0 50 100 1500

0.5

1.0

1.5

δcSystem Load Angle (deg)

Pm

Pe

A2

A1

δ0

Rea

l Pow

er (W

atts

)

System Is Unstable for a 300 ms Fault

0 1 2

1.00

1.04

1.08

1.12



Time (s)

Mac

hine

Spee

d (p

u)

Machine Angle

0 50 100 1500

0.5

1.0

1.5

δc

System Load Angle (deg)

Pm

Pe

A2

A1

δ0

Rea

l Pow

er (W

atts

)

TVA System

TVA Is at the Heart of the EIPP

TCP

Stre

am

Entergy

AEPNYISO

Intranet

RTDMS

Eastern Interconnect Phasor Project (EIPP)

TVA

Ameren

DatAWare 30-Day Sub-Second Archive Array

OPC Based input into DatAWare(Available now)

PDCstream input into DatAWare(Available now)

PC37.118 input into DatAWare

(Available soon)

IEEE 1344 input into DatAWare (Available soon )

Inputs are developed as in-process DatAWare archive assemblies ...

Internet or VPN

NYISO

Internet or VPN

AEP

Internet or VPN

Ameren

Internet or VPN

Entergy

PC37.118output

(Available soon )

PDCstream output

(Available now)

TCP StreamSuper PDC

Internet or VPN

RTDMS

Real-time DataBroadcast

RTDMS

TVA

Internet or VPN

OPC basedreads into

real-time data for small datasets(Available now)

DatAWare PermanentArchive

Web-based tool to retrieve large datasets from real-time data

(Available soon)

Internet or VPN

OPC basedreads into

aggregated data for small datasets(Available now)

Web-based tool to retrieve large datasets from

aggregated data(Available soon)

UDP Stream

James R Carroll - TVADecember 3rd, 2004

PMU Demographics

Real-time Data Acquisition

Internet or VPN

Web-based tool to manage PMU’s,

points and configurations

(Available soon )

24x7 TVA Monitoringof all inter -related systems

Varie

d St

ream

s

WECC Monitor Facilities – 2002

Phasor measurement facilities:

8 PDCs (2 linked together)

40 integrated PMUs7 stand-alone PMUs

~500 primary signals~3.4 Mbytes per minute

PPSM units:~20 units

~560 primary signals~2.8 Mbytes per minute

Other monitors:~10 units ~80 primary signals

Data Streamed from PMUs Through Data Concentrator to BPA

Visualization Software

Why in Relays?

Minimal incremental cost

Reduced current and voltage connections

High accuracy measurements

High reliability and availability

Future control applications

Relays are everywhere

Protection AND Synchrophasors

0

5

10

15

20

25

AG90AB90BCG90ABC90

AG50AB50BCG50ABC50

AG20AB20BCG20ABC20

AG10AB10BCG10ABC10

Fault Type and Distance

Tim

e (m

s)

Remote side trip times WITHOUT synchrophasors Remote side trip times WITH synchrophasors

0

5

10

15

20

25

AG10AB10BCG10ABC10

AG50AB50BCG50ABC50

AG80AB80BCG80ABC80

AG90AB90BCG90ABC90

Fault Type and Distance

Tim

e (m

s)

Local side trip times WITHOUT synchrophasors Local side trip times WITH synchrophasors

SpeedUnchanged

Synchrophasors AND Protection

4 4.1 4.2 4.3 4.4 4.5 4.6 4.7 4.8 4.90

1

2

3

Time (s)

1 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.90

1

2

3

Time (s)

No LostData

Remote Bus Side Phase B Voltage Synchrophasor

Synchrophasor Data Check

Post Fault Analysis

Photo courtesy of Niagara Mohawk a National Grid Company

Microsecond Time Stamping


Synchrophasor Measurement and Application

Phasor and Frequency Measurements

Sinusoidal VoltageTime Waveform Represention

v(t)

0

A

φ

T = 1/f

ω t

)t•f••(2cos•A)t(v φ+π=f••2 π=ω

Euler’s Formula Relates Trigonometric to Complex Exponential Functions

φ⋅+φ=φ sinjcose j

Re

Im

cos φ

sin φφ

ejφ

Cosine Function in Terms of the Complex Exponential Function

)t(v }Re{eA )tfj(2 φ+⋅⋅π⋅⋅=

)tf(2 cosA)t(v φ+⋅⋅π⋅⋅=

}eRe{cos j φ⋅=φ

Phasor Definition AssumesConstant Frequency and t = 0

)t(v }Re{eA )tfj(2 φ+⋅⋅π⋅⋅=

}eARe{e jt)fj(2 φ⋅⋅π⋅ ⋅⋅=

φ∠=⇒→

2AV

Time Waveformand Phasor Representation

v(t)

0

A

φωt

2A

φ

Reference

Voltage Waveforms and Phasorsfor φ = 0º and φ = 90º

t

A

v(t)

00°

A

2

φ=0°

0 t

A

v(t)

φ=90°

0°

A

2

Absolute Time Synchronization

GPS RCVR

PMCU 1

A B

Satellite

GPS RCVR

PMCU 2IRIG-B IRIG-B

Mag/Ang Mag/Ang

Phasor Representation With Respect to the 1 PPS UTC Reference

1 PPS (UTC Reference)

IRIG-B

A

φt

2A

φ

Time Reference: “Start of the second”

ω

Synchrophasor

Phasor calculated with respect to 1PPS UTC Time Reference

Synchrophasor = Synchronized Phasor

Synchronized phasor measurements provide a “snapshot” of the power system using

an absolute time reference.

Voltage Signal at Location AWith Respect to UTC time

v(t)

ωt

φA

1 PPS XL

A B

Voltage Signal at Location BWith Respect to UTC time

ωt

1 PPS

XL

A B

v(t)

φB

φA–φB Determines the Angle Difference Across the Transmission Line

BA φ−φ=φΔ

ωt

v(t)φΔ

1 PPSVB

VA

φΑ

φΒ

Voltage Phasors DetermineSystem Power Flow

XL

A B

P,QAAE φ∠ BBE φ∠

( )BAL

BA sinX

EEP φ−φ⋅⋅

=

( )[ ]BBAAL

B EcosEXEQ −φ−φ⋅⋅=

Phasor Measurement atOff-Nominal Frequencies

}Re{eA)t(v )tfj(2 φ+⋅⋅π⋅⋅=}Re{eA )tf2tfj(2 0 φ+⋅Δ⋅π⋅+⋅⋅π⋅⋅=

}eARe{e )tfj(2t)fj(2 0 φ+⋅Δ⋅π⋅⋅⋅π⋅ ⋅⋅=

)t(2

Aβ∠⇒φ+⋅Δ⋅π=β tf2)t(

Phase Measurementat Off-Nominal Frequencies

v(t)

t (sec)0

T0=1/f0

NominalFrequency

Off-NominalFrequency

φ+⋅Δ⋅π=β tf2)t(

ωβ

ωφ

Phase Difference Remains Constant at Constant Off-Nominal Frequencies

Δφ=ββ=βΔ )t(–)t()t( BA

XL

A B

φB

β(t)

t

φA

φΔ

βB

βA

Correlate the Input Signal Witha Time-Synchronized Signal

to Extract Phase Angle Information

Input Signal

( ) tj–e

0etcosA)t(v ω⋅φ+ω⋅=

tj)t(j)t(j

e0e

2eeA)t(v ω−

φ+ω−φ+ω⋅⎥⎦

⎤⎢⎣

⎡ +⋅=

( )[ ] ( )[ ]{ }φ+ω+ωφ+ω−ω +⋅= tj–tje

00 ee2A)t(v

Low Frequency Signal Isthe Signal of Interest

0ω=ω

( )[ ]{ }φ+ω⋅φ +⋅= t2j–je

0ee2A)t(v

For

Low Frequency (DC)Double Frequency

The Low Frequency Component Includes the Desired Power System Information

( )[ ]φ+ω−ω= tjLF_e

0e•2A)t(v

Principle of AbsolutePhasor Measurement

cos (ω0t)

–sin (ω0t)

v(t)

GPSClock

Refφ

LPF

LPF

x

y

MagandAng φ

vc(t)

vs(t)

V

V


Synchrophasor Measurement and Application

IEEE Synchrophasor Standard

IEEE Synchrophasor Standards

1344 - 1995

PC37.118/D7 - June 2005

Total Vector Error (TVE)

Ideal

IdealMeasured

V

VVTVE r

rr−

≡

Im

Re

VIdeal

VMeasured

VError

Range of influence quantity change with respect to reference and maximum allowable error (ε) in percent (%) for each compliance level

Level 0 Level 1 Influence quantity

Reference condition

Range TVE (%)

Range TVE (%)

Signal frequency

Fnominal ± 0.5 Hz 1 ± 5 Hz 1

Signal magnitude

100% rated 80–120% rated 1 10–120% rated 1

Phase angle 0 radians ±π radians 1 ±π radians 1

Harmonic distortion

<0.2% (THD)

1%, any harmonic up to 50th

1 10%, any harmonic up to 50th

1

Sub-harmonic distortion

<0.2% 1.0 % of input signal magnitude

1 10 % of input signal magnitude

1

Level 0 and Level 1 Requirements

Synchrophasor Message Types

Configuration

Data

Command

Header


Synchrophasor Measurement & Application

Phasor Measurement and Control Units (PMCUs)

SEL-421 and SEL-451Phasor Measurement and Control Units

ConfigurationIRIG-B

V/I Inputs

SEL-421 / SEL-451 Synchrophasor Features (1)

C37.118 V 6SEL Fast Message

ASCIIProtocol

1,2,4,5,10,12,20,30,60Rate [messages per second]Max 32Programmable Digital Status BitsMax 8Programmable Analogs

V1, VA, VB, VC, IW1, IWA,IWB,IWC, IX1, IXA, IXB, IXC

Number of Synchrophasors

1x3-phase Voltages2x3-phase CurrentsInputs

SEL-421 / SEL-451 Synchrophasor Features (2)

32 Bit Floating Point or 16 Bits IntegerData Format

Polar or RectangularSynchrophasor Format

4 settable options for 60 Hz 4 settable options for 50 HzFiltering

MRATE=60 & PAPP=F: 16.65MRATE=60 & PAPP=N: 27.69MRATE=30 & PAPP=F: 33.23MRATE=30 & PAPP=N: 55.82

Total group delay for 60 Hz [ms]

Time-Synchronized Measurements

IRIG-BCOMM

SEL-421 Relay

to Data ServerGPS Receiver

Synchronously Sampled Dataand Time Stamping

ƒs

SynchrophasorAlgorithm

A/DAmplitude

GenerateSamplingFrequency

and Time Stamp

Time

LPFvPhasorsvia Com.Ports

GPSClock Demodulated

IRIG-B

Synchrophasor Signal Processing

ADC Digital LowPass Filter

IIRFilter

FIRFilter

Magnitudeand AngleComputation

AnalogLow Pass

FilterCorrelationV or I

Time (GPS)

Synchrophasor

Protection



SEL-3306 Synchrophasor Processor

SEL-3306Synchrophasor Processor

SEL-3300 Series Computing Platform Outperforms Standard PCs

Heart of the System

SEL-3306 Functions

Communications initiationProtocol conversion

Data alignmentData concentrationData service

PMU Serial

Packets

Format Conv.

Time Align

Packets

Super-Packet Maker

PMU Ethernet Packets

IEEE SuperPackets

IEEE SuperPackets

IEEE SuperPackets

Format Conv.

BPA .INI File

BPA PDCStream

BPA PDCStream

BPA PDCStream

PMCU

PMCU

Comm. Initiation

Communications Initialization

Serial Communications

Ethernet Communications

LAN

SEL-3306

Substation B

Substation B

TCP/IP

Serial

Terminal Interface

Human-Machine Interface

Serial Communications

7 PMU serial ports

Dual independent Ethernet connections

Port 1 jumper selectable between fiber or galvanic interface

Ethernet Connectivity

Protocol Conversion

All received protocols converted to IEEE C37.118 for ease of correlation

Data Alignment

Packets aligned based on timestamp

MWAITP setting identifies how long to wait for data from all PMCUs before data concentration

Data Concentration

Organization of data into IEEE ‘Super Packets’

Data Service

Ethernet output up to six clients

Two output protocolsIEEE C37.118

BPA PDCStreamrequires initialization file

Data Concentration

HMI Overview

Device configuration

Visualizations

Status and logs

User account management

Phase Angle

Frequency

SEL-421 Frequency Measurement

Analogs

Digitals

Status Report

Communications Log

SEL-3306 in Multi-Tear Application

734

WAN

3306

451421

33063306

BPAStream Reader

EPG-RTDMS

WebServer

VisualizationAlarming, Δδ > δThre

Turn data into information

Provide operators with ‘situational awareness’

Can be used by any number of utility departments to improve protection, power delivery, system stability, and future system planning

Key Functions for Synchrophasor Visualization Applications

Several varieties of visualization toolsPower flow analysis

Magnitude, angle, and frequency monitoring

Post disturbance analysis (playback)

Modal analysis

Software Applications

SEL-5078 SynchroWAVeTM Console

Provides two key functionsSEL-5077 SynchroWAVe Server; data collection and time alignment

similar to SEL-3306 but with less functionality

SEL-5078 SynchroWAVe Console; data visualization and recording

SynchroWAVe

Questions?

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