Installation of a Static Var Compensator on to an 11kV network Jonathan Berry 26.10.2011 Substation Technology 2011.

Installation of a Static Var Compensator on to an 11kV network

Jonathan Berry26.10.2011

Substation Technology 2011

Content

•Introduction

•WPD Overview

•Understanding of the problem

•STATCOM Project

•Future learning and developments

Introduction

Jonathan Berry – Innovation and Low Carbon Networks Engineer

Background in primary network and substation design

• Focussed on generation inclusion

Currently working on IFI and LCNF projects

•Working on DG inclusion and network optimisation to support the low carbon transition

Western Power Distribution

•7.6 Million customers over a 55,300 sq kms service area

•Our network consists of 216,000 kms of overhead lines and underground cables, and 184,000 substations

•LV to 132kV Network ownership

Understanding of the problem

As the level of embedded renewable generation and low carbon loads on the DNO’s network increases a core problem is created; maintaining statutory voltage levels.

Example:

An overhead network with a high level of wind generation connected:

At times of low load and high generation, network voltages move towards higher statutory limits, similarly at times of high load and low generation, voltages move towards lower statutory limits

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HV[V]

Node IDP of WT = 1,670[kW] P of WT = 1,420[kW] P of WT = 260[kW] P of WT = 0[kW]

Understanding of the problem

Understanding of the problem

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HV[V]

Node IDP of WT = 1,670[kW] P of WT = 1,420[kW] P of WT = 260[kW] P of WT = 0[kW]

STATCOM Project

Challenge

Distribution Voltage Control to mitigate the voltage fluctuation caused by variations in Load and Generation

Technology

D-STATCOM (Distribution STATic synchronous COMpensator) Trans.

X

Q (reactive power)

D-STATCOM

△V Q≒ ・ X

Inverter

DC Capacitor

Distribution network

Controller

STATCOM Project

4 Project locations:

Agreed

Tentative

Goals

Scope

Benefits

Trial D-STATCOM in rural 11kV networks to address voltage fluctuations

Identify optimum settings to achieve optimum voltage regulation

Development of D-VQC to optimise multiple networked D-STATCOMs

Strand 1 – a single D-STATCOM as a stand-alone voltage control system

Strand 2 – Three additional D-STATCOM units with a D-VQC (Voltage and Reactive Power (Q) Control System) to network devices and optimise across two primary substations

Improvement of power quality, mitigation of voltage spikes issues Increase of network stability, efficiency and load capacity Learning process will have a direct impact on the operation of a

DNO’s distribution system Inform DNO’s business case for alternative responses to network rebuild

STATCOM Project

SubstationSubstation SubstationSubstation

11kv over-head line11kv over-head line

Wind FarmWind Farm

D-STATCOMD-STATCOM

Networkopen pointNetworkopen point

Strand 1

STATCOM Project

5600

5800

6000

6200

6400

6600

6800

7000

0 60 120 180 240 300

Time (sec)

Dis

trib

utio

n Li

ne V

olta

ge (

V)

-450

-300

-150

0

150

300

450

600

Q (

kvar

)

Line Voltage with D-STATCOM

D-STATCOM Q

SVR2 tap

Line Voltage without D-STATCOM (estimation)

-195kVar

-100kVar

60 sec6250V

6515V tap 4

tap 3tap 2

D-STATCOM operation

SVR operation

DG sudden power change

STATCOM Project

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HV[V]

Node IDP of WT = 1,670[kW] P of WT = 1,420[kW] P of WT = 260[kW] P of WT = 0[kW]

STATCOM Project

TerminalTerminal TerminalTerminal TerminalTerminalLDCLDCLDCLDC

SensorSensor

CntlCntl

D-STATCOMD-STATCOM

Tap positionTap positionTap positionTap position

Strand 2

STATCOM ProjectA supervisory and control system for distribution system considering distributed generators to maintain power quality

State estimation- Load current- System voltage

Optimal controlparameter decision- Q(var), Tr.tap, …

System modeling- Network- Load profiling

Simulation/Analysis- Power quality- Power flow

Monitoring- P, Q, V, I

System DB- Line impedance,

configuration- Load, DG, …

Voltagecontroller- D-STATCOM- SVR- LBC

Line

vol

tage

Feeder lengthS/S

Voltageviolation

TimeDG stop

Voltage dip

Flicker

End

Line

vol

tage

Concept of supervisory and control system

Future learning and developments

Conclusion and next steps

Voltage control is key to ensuring system stability in networks where there is embedded renewable energy generation and varying power demand

Further development and product optimisation

Policy discussions around network inclusion, ownership and operation