0605 Generator Compliance

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UK Transmission

Generation Compliance Process

Ian Nuttall

Helge UrdalGeneration Dynamic

Performance

Operations and Trading


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Conventional Power StationsSynchronous Machines - Voltage Control

Field Voltage, EFD

Excitation

System

b

c

a

b

c

Automatic

VoltageRegulator

a

The Purpose of the AVR is to Control the Machine

Terminal Voltage - This is achieved by adjusting the

setting of the Excitation System which ultimately adjuststhe field voltage seen by the machine

In the UK it is common practice to use the AVR to fix the

terminal voltage of the machine and adjust the HV Grid

Voltage by tapping the Generator Transformer

Generator

Transformer

with Tap

Synchronous

Machine

To Grid

(400 kV)

Signals to Measure

Terminal Voltage, Vt


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Conventional Power StationsSynchronous Machines - Frequency Control

Grid

(400 kV)

Power

SignalFrequency

Signal

GovernorControl

System

Controlled

Torque

Power

Turbine

Frequency Control is achieved by the

governor control system. TheGovernor will sense variations in

system frequency and adjust the

power output accordingly.

The Governor will initiate changes tothe turbine not the Machine.

Power Output from Machine

Single Line Representation

Fuel & Air

or Steam

Synchronous

Machine


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Overview of Compliance Process

Technical appraisal of critical control systems and Analytical /Modelling work

Compliance Testing

Life-time compliance / Event Investigation / System monitoring

Main Aims:


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Purpose of Compliance

Ensure compliance with Regulatory and Commercial documents

(CUSC, Grid Code, BCA, MSA)

Avoid connection of plant with inherent design or commissioning defects

Excitation failures can lead to:

Pole slipping or Generator instability

Governor control defects can lead to

Generators responding erratically with frequency

Risk of generator trips at times of system stress


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Typical Project Timeline

3 Months

18 to 24 Months

6 to 12 Months

Application

&

Offer

Tender

&Construction

Commissioning

& Approval

Preliminary Studies

Functional Spec.

Offer

Data Analysis, Model

Simulation, OperationalNotification Process

On-site Testing

Model VerificationModel to Database

DurationProject Milestones NGC Activities

Lifetime Ongoing

Compliance

System Incident

Analysis

Stage

1

2

3

4


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Timeline Stage 1

Application and Offer


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Development of New Technology

Liase with manufacturers on their plant compliance issues

Understand changes in technology

Ensure compliance process evolves to meet changes within the

industry

Discuss with developers the compliance issues related to any unusual

proposals

Application and Offer


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Timeline Stage 2

Tender and Construction


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Technical Appraisal of Generating Plant

Operational Notification Process

Discuss compliance issues with project developers

Ensure any problems are identified and addressed early

Tender and Construction


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Appraisal of Excitation Control Systems

Excitation Control System Specification to meet the Grid Code and

Bilateral Agreement

Ceiling voltage

Exciter type (static or brushless)

With or without Power System Stabiliser (PSS) Manufacturers PSS tuning study results


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Appraisal of Governor Control Systems

Governor System / Module Load Controller details

Droop settings

Target frequency setting facility

Module frequency operating range 47 to 52Hz

Governor deadband

Load rejection / island mode operation

Compliance with CC6.3.3 / BC3.7.2


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Timeline Stage 3

Commissioning and Approval


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Compliance Testing

Commissioning and Approval


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Compliance Testing

Why do we need to test?

To confirm that what is expected from the design is put in place

.... and the right place! Are the systems working correctly ?

Verify the stability and performance of the control systems

Check the model supplied accurately represents the plant as connected


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Typical Excitation System Tests

Open circuit and full load step responses

Step test with and without power system stabiliser if applicable

On load power spectrum analysis for PSS applications

Under and Over-excitation limiter functionality


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Typical Governor System Tests

On load frequency injections at a number of loading points to

determine;

Control System robustness

Governor deadband and droop

CC6.3.3 functionality Plant frequency response capability data to populate a MSA frequency

response matrix

Load rejection tests to determine the capability to regulate frequency ina power island


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Timeline Stage 4

Ongoing Compliance


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When do we get involved ?

Event based analysis of performance

Requests to changes in machines response capability

Changes to key performance affecting components

Ongoing Compliance

E t A l i


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Event Analysis

Investigate events of non-compliance or unusual plant behaviour

Check responsive plant against contract for frequency events outside

operational limits

For significant frequency deviations conduct a review against CC6.3.3 /BC3.7.2 requirements

E t A l i l (R )


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Good Response Performance

80%

85%

90%

95%

100%

105%

0 5 10 15 20 25 30

TIME (mins)

G

ENSETOUTPUT(%

ofRegCap)

49.8

49.9

50

50.1

50.2

50.3

FREQUENCY

(Hz)

CAPPED COMMITTED LEVEL (MW ) MEL FREQUENCY

Event Analysis example (Response)


80%

85%

90%

95%

100%

105%

0 5 10 15 20 25 30

TIME (mins)

GENSETOUTPUT(%

ofRegCap)

49.8

49.9

50

50.1

50.2

50.3

FREQUENCY(Hz)

CAPPED COMMITTED LEVEL (MW ) EXPECTED RESPONSE (MW ) MEL FREQUENCY


80%

85%

90%

95%

100%

105%

0 5 10 15 20 25 30

TIME (mins)

G

ENSETOUTPUT(%

ofRegCap)

49.8

49.9

50

50.1

50.2

50.3

FREQUENCY

(Hz)

GENSET OUTPUT CAPPED COMMITTED LEVEL (MW ) EXPECTED RESPONSE (MW ) MEL FREQUENCY

E t A l i l (R )


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Event Analysis example (Response)

Poor Response Perfomance

80%

85%

90%

95%

100%

105%

0 5 10 15 20 25 30

TIME (mins)

G

ENSETOUTPUT(%

ofRegCap)

49.8

49.9

50

50.1

50.2

50.3

FREQUENCY

(Hz)

GENSET OUTPUT CAPPED COMMITTED LEVEL (MW ) EXPECTED RESPONSE (MW ) MEL FREQUENCY

E t A l i l (O ill ti )


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Event Analysis example (Oscillations)

Example of unexpected oscillations

40%

45%

50%

55%

60%

65%

70%

0 5 10 15 20 25 30

TIME (mins)

GENSETPOWER(%RegCap)

49.8

49.9

50

50.1

50.2

50.3

50.4

FREQUENCY(Hz)

GENSET OUTPUT CAPPED COMMITTED LEVEL (MW ) SEL FREQUENCY

Summary


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Summary

Our compliance process and the team aims are to:

work with Generators to achieve an understood compliance position

adopt a pragmatic approach to confirming compliance

witness compliance tests to confirm the expected performance

investigate events which could indicate failure of plant to maintain

compliance

Maintaining compliance throughout the plant

lifetime is vital to transmission system integrity

A new Era


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A new Era

World of Wind - What difference does it make?

Compliance of Power Park Modules


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Compliance of Power Park Modules

Key Issues

Compliance task - different requirements & project characteristics

Process reviewed

Guidance Notes for Power Park Developers

Help available to get started - site specific documentation

Your feedback on process awaited

Compliance task


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Compliance task

Different requirements - New issue of Grid Code

Different project characteristics

Thermal Power station - few large synchronous plant

Power Parks - many asynchronous generators

Different types of asynchronous generators

Extensive use of power electronics

New Grid Code - 1 June 2005

web address < www.nationalgridinfo.co.uk/grid_code/index.html >

Requirements based on Point of Connection - variations size & location

New topic - Fault Ride Through

Projects characteristics

Size range extended from 5 MW to 1000MW+

Volume of projects - 10 fold increase.

Compliance Process review


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Compliance Process review

Fresh look at process starting with objectives. For:

System Operator / Transmission Owner

Generator / Developer

Contractor / manufacturer

Compliance moved from Generator Terminals to Point of Connection

Generic Review of Type information

Strong emphasis on self certification Minimise expensive site activity

Less predictable source of power

Consideration of part move to remote access to live data during testing



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Guidance notes on how to demonstrate compliance - now issued

web address < www.nationalgridinfo.co.uk/grid_code/mn_associated.html >

Intended to provide Project Managers with clarity

Practical methodology to save resources for 3 interest groups by maximising reuse of compliance material

providing a clear path to Operational Notification

Uniform compliance review by standardised summary & compliance sheets

Help available to get you started

project specific compliance sheets - removes N/A requirements

Compliance


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Compliance

.... and at sea

On land .

Any questions about Compliance


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Any questions about Compliance

for Generators - Contact us

We will both be around through lunch

In NGT House in Warwick

By telephone to the team phone on (01926) 654601

Date post:	03-Jun-2018
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0605 Generator Compliance

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