Synchro Phasor Monitoring System

Ray Doyle

Generator Forum 15th May

Presentation Content

• Update on status of SPM system

• Use of SPM system during North-South Separation

• Use of system during Storm Darwin

• Use of SPM to observe generator behaviour during

Testing

• Recent Power System Events of Concern

SPM System Status Update

• 19 PMU’s now operational – 14 in Ireland

– 4 in Northern Island (Coolkeeragh * 2, Moyle & Castlereagh House)

– 1 in UK on East West Interconnector

– Additional Units planned for NI

• Additional recorders installed in Ireland with PMU

capability will be connected to the SPM system as

bandwidth required to stream data becomes available

• Real Time Phasor Data now available to NCC and will be

available to CHCC in near future

–

System Frequency Measurements

Frequency Spectrum Analyser

Generator Stability Status

Control Centre Frequency Oscillation Monitoring Display

Oscillation Magnitude (MW) & Frequency

North-South system Separation 28th Nov 2013

Forced Outage of Louth-Tandragee 275 kV Interconnector

49.9

49.92

49.94

49.96

49.98

50

50.02

50.04

50.06

50.08

28

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-13

08

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Fre

qu

en

cy (

Hz)

System Frequencies pre/post System Separation

South

North

Moment of Separation

North-South Re-Synchronisation 30th Nov 2013

49.94

49.95

49.96

49.97

49.98

49.99

50

50.01

50.02

50.03

50.04

50.05

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Fre

qu

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cy (

Hz)

System Frequencies during System Re-synchronisation

South

North

Matching of System Frequencies Moment of Re-Synchronisation

North-South Re-Synchronisation 30th Nov 2013

-300

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-50

0

50

Ph

ase

An

gle

(d

egr

ee

s)

Voltage Phase Angles during System Re-synchronisation

South

North

Matching of System Angles Moment of Re-Synchronisation

The Synchro-phasor Monitoring System

Provides Control Centre With

• Immediate Identification of System Splits – Information of the state of each sub system

– Means to direct efforts when re-synchronising two parts of the system

• Generator MW & MVAr output

• Bus Voltages / Frequencies / Phase angles

• Oscillation magnitudes and frequencies

• Indication of Faults, Fault Types and Durations

• Partial Backup for Scada/EMS failure

Use of Phasor Monitoring system

during Storm Darwin 12th February

• 67 faults on 110 kV System from 11:36 to 16:21 – Seven 110 kV load stations disconnected

– Three 110 kV wind farms disconnected

• Eight lines forced out of service at end of storm

• All generators rode through all faults

Voltage Dips Across the Network

11:30 to 15:30

Impact at various networks nodes

available to operators seconds after fault

Line Trip, Auto-Reclose & Trip 1 Ph to E fault, line structure okay, attempt restoration

1 s per division

Line Trip, Auto-Reclose & Trip Ph to Ph fault , possible structural damage, no restoration attempt

~ 0.5s per division

Fault evolving from 1 to 2 to 3 phase (suggest structure failure thus no attempt to restore)

Use of Phasor Monitoring system

during Storm Darwin 12th February

• SPM system can provide detailed fault

information to control centre in real time

• This supplements existing information such as

Protection relay signals

• New information is graphical thus faster and

easier to interpret – In many instances can reduce decision making time

Use of SPM to observe generator

behaviour during Testing

• The SPM now allows observation of generator testing in

real time – Any issues the machine is causing for the system or other generators can be observed

• Should allow for more secure operation of the system

when tests with significant impact potential are being

carried out

• Allows decisions to be made on continuing with test

programme or pausing to investigate issues

Example of Setpoint Step Change to AVR

238.9

kV L-L

-24.6

MVAr

17:19 17:18 17:17 17:13 17:12 17:11

12/03/2014 17:20:00Measured Voltage and Reactive Power

237.8

238.0

238.2

238.4

238.6

238.8

239.0

239.2

-44.0

-41.1

-38.3

-35.4

-32.6

-29.7

-26.9

-24.0

Reaction of Generator MVAr output to Disturbance

introduced by Transformer Switching

234.2

kV L-L

-74.7

MVAr

20:44 20:43 20:42 20:38 20:37 20:36

12/03/2014 20:45:00Measured Voltage and Reactive Power

222.0

224.0

226.0

228.0

230.0

232.0

234.0

236.0

-90.0

-77.1

-64.3

-51.4

-38.6

-25.7

-12.9

0.0

Reaction of Generator MW Output Disturbance

introduced by Transformer Switching

E.Freq;Hz

50.010

Hz

E.3P;MW

429.2

MW

20:40:06 20:40:04

12/03/2014 20:40:07Local Frequency and Real Power

49.960

49.970

49.980

49.990

50.000

50.010

50.020

50.030

380.0

397.1

414.3

431.4

448.6

465.7

482.9

500.0

Recent Incidents

• Two Major Incidents currently under Investigation

– 22nd April Under-frequency Load Shedding

following generator trip

– 27th April Major System Oscillation following

generator trip

System Frequency 22 April 2014 17:31 to 17:46

• 370 MW Gen Trip

• 180 MW load disconnected approx

• Frequency sub 49.9 Hz ~ 9 min

Comparison Event

• 357 MW Trip 27 May 2013

• Frequency recovered to 49.9 Hz ~ 9 seconds post Nadir

System Frequency 27 April 2014 21:40

• 370 MW Trip 27 April 2014

• Severe Oscillation in generator outputs around Nadir

20s per division

Frequency & Voltage Oscillations

Looking Ahead

• Trend is to have fewer conventional units

committed than in the past

• No Margin for underperformance of any unit – In terms of reserve provision, stability, fault ride through, voltage support

• EirGrid & Generators to Collaborate on – More robust testing of machine capability and dynamic performance

– Enhanced Performance Monitoring

– Linking payments to actual performance with the potential for declaring

services unavailable following evidence of under performance

– Incentives to deliver the required performance

Thanks for your Attention

Questions