Christian PAYERL ABB FACTS Grid connection of Wind Farms · Point A is equivalent to: 0.95 leading...

© ABB Group May 28, 2010 | Slide 1

ABB FACTS Grid connection of Wind Farms

Christian PAYERL


ABB – Power of Wind


ABB FACTS

300 engineers, highly skilled in the following disciplines:

Development

Marketing and Sales

System studies and design

Project management

Quality control

Testing and commissioning

After sales


FACTS Applications Flexible AC Transmission Systems


FACTS Business structure and development

Static Var Compensation - Utilities Series Compensation

TCSC


SVC Light® (STATCOM) SVC for Power Quality

FACTS Business structure and development


ABB SVC Installations

450 SVC installations (more than 310 for Power Quality)


SVC - Static Var Compensator SC – Serial Compensations

Start of research

First commercial installation

Installed power

Number of installations

1967 1945

1972 1950

52.000 Mvar 60.000 Mvar

415 235


Generator Size Background


System Studies - Grid Codes Many markets are currently installing or discussing

installing large amounts of renewable generation

Of all the renewable energy sources, wind is currently the most viable technology

In the past wind farms were generally small (ten’s of MWs) and connected mainly to distribution systems

Today most of the wind farms planned are +100 MWs and many are being connected to sub-transmission and transmission level

This prompts the need for systems analysis in the early stages of wind farm development to ensure proper integration into the transmission system

Background

Why shall large wind plants NOT match the same demands as other large traditional power plants ?


Grid Connection

Onshore

Offshore

AC networkCollection

grid

On-shore S/S

Reactive PowerCompensation

Off-shore HVSubstation

Sub-Sea Export Cable transmission

Background


Reactive Power Balance

Voltage Stability

Frequency Control

Fault Ride-Through

Power flow

Critical aspect, Grid compliance - wind power

PICTUREJPG-FORMAT

WEB OPTIMIZED RESOLUTION

General


Voltage & Transient Stability

Power Oscillation Damping

Load Balancing

Power quality issues

Harmonic Mitigation

“Flicker” Mitigation

Voltage Transient Issues

Resonance Issues

Other Advantages with an SVC at the GCP

PICTUREJPG-FORMAT


General


Static analysis To define apparatus data and reactive

power demand

Load flow

Short circuit

Dynamic analysis To verify system design

Harmonics

Transient Stability

Transient overvoltage

Relay coordination

Power quality analysis Harmonics

Flicker

System Design Studies


European Wind Integration Study - EWIS

EWIS – Report

Page 22, page 24, page 47f

General


Large Wind Farm Grid Connection

Source: National Grid

Reactive PowerBalance


Reactive PowerReactive Power is a local phenomenon and cannot be transmitted

effectively across large distances.


The German power factor requirements for Prated above 100MW


Reaktive power balance

Grid Connection Point

Important impedance

P=Pgen-losses

Q=Qgen+Qcabel-I2XPgen

SVC

IG

DFIG

FPC

Qgen

Lagg

ing

MVa

rLe

adin

g MW

MVa

r Lagg

ing

Lead

ing MW

Lagg

ing

MVa

rLe

adin

g MW

+.95pf

-.95pf



Reactive power balance

Generators giving local reactive power support are being retired, this disturbs reactive power balance.

Load sensitivity regarding both fundamental frequency and harmonic voltages is increased. Customers are more sensitive to outages.

Changed and often reversed power flow calls for studies and actions.



Typical Requirement at the Connection Point (NGT)


P (MW) Rated Power output (MW) 100%

20%

A C D B Q (MVAr)

Point A is equivalent to: 0.95 leading Power Factor at Rated MW outputPoint B is equivalent to: 0.95 lagging Power Factor at Rated MW outputPoint C is equivalent to: -5% of Rated MW output Point D is equivalent to: +5% of Rated MW output


Possible FACTS Application

An SVC at the Connection Point can be used to control the entire, or part of, the reactive power.

An SVC at the Connection Point makes it possible to minimize the losses within the wind farm and mitigates the risk for over voltages as well as reduce resonance problems.



Historically, wind farms have been excluded from the demand that generating devices should contribute to voltage stability. They cannot, however, expect to enjoy this favorable treatment forever.

Many regulatory authorities adapt the requirement that the wind parks should be able to vary there reactive power output depending on the grid voltage level.

Voltage Stability, Introduction

PICTUREJPG-FORMAT


Voltage Stability


Possible FACTS Applications

An centrally placed SVC stabilizes the grid.

A solution with an SVC at PCC contribute to voltage stability independent of the active power production.

Voltage Stability


PICTUREJPG-FORMAT


Frequency control

As well as for the voltage stability,

new wind generation units are requested

to contribute to frequency stability.

Frequency Control


Frequency controlFrequency

Control


Possible FACTS Applications Frequency Control

Active power needed.

A FACTS device equipped with an energy storage is a possible solution.

Clustering of smaller wind farms into larger production units makes it easier to apply solutions.


Fault ride through

Minimum fault the system is required to survive.

Symmetric and asymmetric faults.

Depending on voltage level at Connection Point.

Post fault behavior.

Minimum active power as compared to before event.

Reactive power and voltage control.

FaultRide-Through


Fault ride throughFault

Ride-Through


Advantages with an SVC at Connection Point

Fault Ride-Through is first and foremost a question for the Wind turbine generator manufacturers.

An SVC can have a significant impact on the system after clearance of the fault.

FaultRide-Through


Wind Turbine Concepts

Fixed speed

Induction generator (SCIG - fixed speed)

Danish concept (2

Induction generator with variable slip (WRIG)

Variable speed

ASG with Inverter system (SCIG)

Double feed induction generator with PWM inverter (WRIG)

SG with Inverter system

General


Reactive power, voltage control

Voltage stability, fault ride through

Induction generator direct connected to the grid




Danish concept




Induction generator with variable slip




Wind turbine with inverter in main power circuit


Synchronous generator

Pitch control wind turbine Variable Speed Multi-Pole Synchronous

Generator – direct driven Rectifier + Inverter

wind

SG

ACAC

Gtransformer

grid/standalone

PowerConverter




Double feed induction generator with PWM-inverter


Background

Modelling aspects

Aspect Model level Time scale Tool

Wind turbines mechanical loads RMS 10-1 s – 103 s HAWC

Wind turbines power quality RMS 10-1 s – 103 s DigSilent

Wind turbine control system RMS/EMT 10-3 s – 102 s Matlab

Wind turbine switchings EMT 10-3 s – 101 s DigSilent/SABER

Grid faults EMT 10-6 s – 10-1 s PSCAD, EMTDC, SIMPOW, DigSilent

Power electronic control and design EMT 10-9 s – 10-2 s SABER

Other aspects


Harmonic Requirements Harmonic emission

Background emission onshore grid

WTG:s System resonance

200 400 600 800 1000 1200 1400 1600 1800 2000 2200 2400FREQUENCY HZ

0

200

400

600

800

1000

0

200

400

600

800

0,0

10,0

20,0

30,0

40,0

50,0

0,00

1,00

2,00

3,00

4,00

5,00

6,00

NODE PL33-W5B U POS. p.u. 33.0000/ SQRT[3] kV NODE PL33-W6A U POS. p.u. 33.0000/ SQRT[3] kV NODE PL33-W4A U POS. p.u. 33.0000/ SQRT[3] kV NODE PL33-W3A U POS. p.u. 33.0000/ SQRT[3] kV

Harmonic Filter Design

Type of filter, S-filter, C-filter, etc.

Resistor for increased damping

Resistor => Heating => Losses => Forced Ventilation

Network studyNetwork study


Reasons for bad power qualityPower Line (T or D)

200 400 600 800 1000 1200 1400 1600 1800 2000 2200 2400FREQUENCY HZ

0

200

400

600

800

1000

0

200

400

600

800

0,0

10,0

20,0

30,0

40,0

50,0

0,00

1,00

2,00

3,00

4,00

5,00

6,00


↨ P, ↨ Q

IG

DFIG

FPC

Power quality


What is flicker ?IEC 61000-3-7,

IEC 61400-21

UK, P28

China, GB/T 12326-2000

Flicker

Definition

A group exposed to a flicker dose of Pst(99%) = 1.0, 50 % of them can observe the light flicker.


Network In/out switching

Tower shadow

Power electronic failure

Background flicker

Flicker


Continouse operation

Switching operation

Flicker


Can harmonics create problems ?

IEC 61000-3-6, THD < 3.0%, Odd.. Even ..

IEC 61400-21

China, GB/T 14549-93

IEEE, THD < 1.5 %, Odd, even, current..

Communication systems and modern remote metering devices (Turtle)

Overheating of power transformers

Harmonics


Network

200 400 600 800 1000 1200 1400 1600 1800 2000 2200 2400FREQUENCY HZ

0

200

400

600

800

1000

0

200

400

600

800

0,0

10,0

20,0

30,0

40,0

50,0

0,00

1,00

2,00

3,00

4,00

5,00

6,00


DFIG

FPC

Harmonics


Shunt banks Small SVC Full rated SVC SVC Light (STATCOM) SVC Light Energy Storage Hybrid solutions

ABB Smart Grid Wind power integration in networks

ABB Solutions


Mechanical switched capacitors from ABB

SIKAP - enclosed capacitor bank

Q-bank - open capacitor bank

CHARM – filter banks

ABBACUS – containerized capacitor bank 12-24 kV

EMPAC- enclosed capacitor bank 36 kV

ABB Solutions


SVC Light Energy Storage

Energy storage connected on DC-side of converter (SVC Light)

Size depends on power level and duration

Charge energy equal to load energy

Focus on “dynamic”, manages:

High number charge and discharge cycles

High Power at medium duration

Chosen high performance battery as energy storage

ABB Solutions


SVC Light Energy Storage SVC Light

First project in 1999 for flicker mitigation of electric arc furnace

In total 12 project for both industry and utility applications

Power range up 164 Mvar, direct connected without transformer up to 35kV grid

SVC Light Energy Storage First project in 2009 Energy Company in UK System Voltage 11 kV Reactive Power:

600 kVAr inductive 600 kVAr capacitive

Active Power: 200 kW during 1 hour 600 kW (short time) Picture of the new Li-ion battery

after testing, October 2008

ABB Solutions


SVC Light med energilager

February 12, 2010| Slide 57© ABB Group

50 m65 m

Typisk layout för 20 MW under 15 mininuter och +/-30 Mvar kontinuerlig

ABB Solutions


AC Offshore system issues

PCC

PQ working area

Compensation(Localization?!)-Static-Dynamic-SVC vz STATCOM-SVC Light/DynaPow-MINICOMP

Cable parametersCable cost-Laying/burying-Trench width

Harmonics

Energization

Shield overvoltage

XkWeight

ProtectivecapacitorGrounding

-System-Equivpotential

Voltage level

Vt and ferroresonanceABB do not have a voltage divider above 24 kV

Aux. Power-Diesel-Energy Storage

RMU 36 kV

Protectivecapacitor

Type, ratio

Redundancy

RC-protectionSurgearresters

Faultcurrent

CircuitBreaker-Vaccum

Power Electronics

Booster

BLASIGGearbox

d d

Bergeron study, n*d

Fault detection-Ground faults-Short Circuit Currents-Need for further protection?

EMTDC model from SANDYS

Grounding?

CableShielding

Separate 600 V auxiliary grid?

Platform

Ride through

Thermal Cyclic rating

Lightning

Collection Grid Switchboard-Energizing-Normal Operation

ABB Off-shoreSolutions

Christian PAYERL ABB FACTS Grid connection of Wind Farms · Point A is equivalent to: 0.95 leading...

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