WECC_HVDC_Task_Force-7-12-2011_03

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ABB Group July 12, 2011 | Slide 1

Dave Dickmander ABB Grid Systems, Power Systems Consulting

WECC HVDC Task ForceModeling of HVDC


2010

Gotland HVDC transmission 20 MW

100 kV

Xiangjiaba-Shanghai 6,400 MW

800 kV

In between

61 HVDC Classic projects and 15 HVDC Light projects

14 HVDC upgrade projects >50% global market share Continuous technology

leaps

1954

HVDC by ABB


61 HVDC Classic Projects since 195414 HVDC Classic Upgrades since 199016 HVDC Light Projects since 1997

TrollNelson River 2

CU-project

Vancouver IslandPole 1

Pacific Intertie

Pacific IntertieUpgrading

Pacific IntertieExpansionIntermountain

Blackwater

Rio Madeira

Inga-Shaba

Brazil-ArgentinaInterconnection I&II

EnglishChannelDrnrohrSardinia-Italy

Highgate

Chteauguay

Quebec-New England

Skagerrak 1-3

Konti-Skan

Baltic Cable

FennoSkan 1&2

Kontek

SwePol

ChaPad

Rihand-Delhi

Vindhyachal

SakumaGezhouba-Shanghai

Three Gorges-Shanghai

Leyte-LuzonBroken Hill

New Zealand 1&2

Gotland Light

Gotland 1-3

Murraylink

Eagle Pass

Tjreborg

Hllsjn

Directlink

Cross Sound

Italy-GreeceRapid City

Vizag II

Three Gorges-Guandong

Estlink

Valhall

Cahora Bassa

SapeiSquare Butte

Sharyland

Three Gorges-Changzhou

Outaouais

Caprivi Link

Hlnbeir- Liaoning

Lingbao II Extension

Xiangjiaba-Shanghai

BorWin1

NorNed

Apollo Upgrade

EWIC

IPP Upgrade

Itaipu

DolWin1

NordBalt

Skagerrak 4

North East Agra

Jinping - Sunan

HVDC by ABB


HVDC Models for Planning Studies

What do I need to know about HVDC? What Basic Information on HVDC do I Need? How can I model HVDC in:

Powerflow Studies Stability Studies

What are the System Benefits? Relevant Project Examples?


Classic HVDC Station Components

11thharmonicfilter

11thharmonicfilter

13thharmonicfilter

13thharmonicfilter

High-passfilter

High-passfilter

AC yard

Valve hall

AC bus

Pole line

Electrodelines

Pole line

DC filter

DC yardConverter


HVDC Classic System Characteristics

DC-Side impedance is dominated by smoothing reactor

High impedance of smoothing reactor is reflected to AC side of converter

High Internal Impedance => Current Source HVDC Controls: Current regulator with outer power

control loop Powerflow representation: Load Model


HVDC Classic Powerflow Model

Pcon = +1.0 PU (-1.0 PU)

Qcon = -0.5 PU (-0.5 PU)

Qcap= +0.5 PU


Classic HVDC Reactive Power Balance


HVDC Simplified Powerflow Models

Preliminary Screening of Certain Criteria:

Thermal loading Reactive power requirements Power transfer limits and changes in the

system power flow Voltage profiles System losses


HVDC Classic Detailed Powerflow Models

Provide HVDC System Operating Parameters:

DC Voltages Converter P & Q DC Currents , , u (firing, extinction, and overlap angles) Converter Transformer Taps DC System Losses


ABB HVDC Classic Main Circuit Calculations

Typical estimates, Nominal conditions: =15 degrees dxN= 0.065 drN= 0.003 UT=0.3/250 pu (0.12%) of UdN /6-pulse

bridge; i.e., negligible Equations per 6-pulse bridge Once the above definition of dx is taken into

account, and UT is neglected, the equations are essentially the same as those in the PSS/E Manual.

Ndi

dNCx U

IXd0

3 =

230 Ndi

vNUU =

dNvN II = 32

dCRdidr IXUU = 3)cos(0


ABB HVDC Classic Operating Principles

6-Pulse Rectifier Equivalent Circuit


ABB HVDC Classic Operating Principles

Rectifier Operation Inverter Operation


A more detailed powerflow model of HVDC is necessary in order to be able to initialize the dynamic model.

It is also useful for providing the approximate steady-state response of HVDC to changes in terminal voltage during powerflow studies.

HVDC Classic Detailed Powerflow Models


Example of Data for Entry into PSS/E

Bridges in seriesPdN, bipolar, SETVAL MWPdN 12puls MWUdN, bipolar, VSCHEDULE kVUdN 12puls kVIdN kAalphaNdxNdrNUT kVUdi0N kVUvN kVIvN kATap, maxTap, min

Line side voltage, EBASR kVTRR RatioXCR Reactance OhmRCR Resistance OhmTap, step puTMXR, max tap puTMNR, min tap pu


Monopolar HVDC Transmission


Effect of Current Margin


VDCOL and Complete Characteristics

VDCOL Function Complete Characteristics


VDCOL Function

HVDC Classic Control

VDCOL characteristics Main characteristics With/Without VDCOL

Avoids power instability during and after disturbances in the a.c. network Defines a fast and controlled restart after clearance of a.c. and d.c. faults Avoids stresses on the thyristors at continuous commutation failure Suppress the probability of consecutive commutation failures at recovery


HVDC Classic Dynamic Model

PC VDCOL CCA

GR

FPD

DCR

CCA: Current Control AmplifierVDCOL: Voltage-Dependent Current Order LimiterGR: Voltage (Gamma) RegulatorPC: Power ControlDCR: Power-Frequency RegulatorFPD: Power-Frequency Measurement

_

_

+

Ud

Id

Uac

P Order

P

I

Iac

Uac

AC SystemfP

Imargin


HVDC High-Level Controls

Enhancement of System Performance by High-Level Controls:

Frequency Control Modulation for System Stabilization System Oscillation Damping Reactive Power Control AC Voltage Control Fast Remedial Action Responses


HVDC High-Level Controls

Examples of System Performance Enhancement:

Power step runback or step increase: IPP, others

Voltage stabilization of weak ac network Blackwater, others

Power modulation to increase system stability: Vindhyachal (India), others

Control of frequency on islanded systems: IPP, HQ-NEH Phase II, New Zealand


HVDC Classic Modeling in PSLF

Recent development focus is on PSLF dcmt model

EPCL-PSLF interface via dcc[@index].cosctlang GE has increased limits for dcmt for latest models


IPP Southern Transmission System (STS) Milford Wind (MWC) Interconnection:

400 MW Wind Power Wind Scheduled over HVDC Integration with 1920 MW IPP STS Integration with 2400 MW Upgrade

IPP PSLF Model: Current Regulator (CCA) VDCOL Wind Power Controls DC Power Schedule Calculator Frequency Controls:

Constant Frequency Control Frequency Control with Deadband

Pole Loss Compensation


IPP STS PSLF Model Results


Blackwater HVDC Back-to-Back

System Characteristics: 200 MW bi-directional 3-winding converter transformers Weak AC system on PNM side SVC mode

Blackwater PSLF Model: Current Regulator (CCA) AC VDCOL AC Voltage Regulator DC Voltage Regulator SVC Regulator


Blackwater PSLF Model Results


ABB Group Slide 28PowDoc id

HVDC Classic - Current Source Converters (CSC) Line-commutated thyristor valves Requires 50% reactive compensation (35% HF) Minimum short circuit capacity ~2x converter rating Telecommunication between stations for best performance Significant inherent short term overload capability Reversal of power requires polarity reversal of the DC voltage (takes time)

HVDC Light - Voltage Source Converters (VSC) Self-commutated IGBT valves allows for independent control of P and Q Compact design due to a minimum of filters and reactive compensation Standard transformers without DC exposure Black start possible / Islanded wind farms Low short circuit conditions Reversal of power can be made instantaneously by current reversal

VSC Compared to HVDC Classic



Two-level converter phase-to-neutral voltage

+ Ud

- Ud

HVDC Light Historical ReviewGeneration 1, 1997-2001

Two-level ConverterHigh switching frequencyFilters required



Three-level converter phase-to-neutral voltage

+ Ud

- Ud


Three-level ConverterSwitching frequency reducedHarmonic generation

improved



Two-level converter phase-to-neutral voltage

+ Ud

- Ud


Two-level ConverterOptimized IGBT Lower switching

frequency


HVDC Light (3G) Station Components



+ Ud

- Ud

+ Ud

- Ud

HVDC Light Historical ReviewGeneration 4, 2010-Present

Cascaded Two-level ConverterExcellent output voltage

quality

Scalable to high voltages


HVDC Light (4G) Cell

T1

T2

Uc

Ui

Uo

+

-

T1 on, T2 off: Uo=Ui. Cell is Bypassed T1 off, T2 on: Uo = Ui Uc. Cell is Inserted;

cap charges when current is positive T1 off, T2 off: Cell is blocked; current

conducted only through diodes; cap charges when current is positive


HVDC Light (4G) Operating Principles Cascaded Two-Level (CTL) Converter Low Switching Frequency Per Cell Multiple Cells give High Effective Switching Frequency


HVDC Light (4G) Station Components



Three terminal configurationsSymmetric monopoles

Disconnector, closedDisconnector, openSwitch, closedSwitch, open

+

-

+

-

+

-



Three terminal configurations Bipole with metallic neutral

Disconnector, closedDisconnector, openSwitch, closedSwitch, open

+

-

+

-

+

-



HVDC Light Reference Projects


HVDC Light System Characteristics

DC-Side Impedance Dominated by DC Capacitor Low Impedance of DC Capacitor is Reflected to AC

Side Low Internal Impedance => Voltage Source Controls may be configured to impart a current

source behavior at fundamental frequency (vector current control)

Powerflow Representation: Generator


Power Flow Modeling

Pcon = +1.0 PU (-1.0 PU)

Qmax = +0.35 PU

Qmin = -0.50 PU

Qcap = 0 PU !

HVDC Light Steady-State Model



System Parameters Valve current

Modulation index

AC and DC voltage

DC cable rating

Cell voltage

HVDC Light Converter Characteristics


Two Power Flow Generators

HVDC Light Power Flow Model


HVDC Light System Principles

P,Q

vULU

X

LU vU

X

I

=

=

X))cos(UU(UQ

)sin(X

UUP

vLL

vL



Independent control of active and reactive power Step in active power order


VSC Converter Control Methods (Literature) Vector-Current Control:

Dominant Method of Controlling VSC Converter current is controlled directly

Passive Network Control: VSC Sets Voltage Magnitude and Angle AC Network Determines VSC Power

Power-Angle Control: VSC Calculates Voltage and Angle for Desired P and Q Converter current is not limited (disadvantage)

Power-Frequency Control: Imparts Synchronous Machine Behavior to VSC


HVDC Light Vector-Current Control

PCC PCC

Inner current control

Phase current

limit

Converter voltage

limit

Active power control

DC voltage control

AC voltage control

Reactive power control

Uac ref

Uac ref

Qref

UacCtrl

Qref

QCtrl

Pref

Pref

Udc ref

UdcCtrl

PCtrl

UdcUpcc


HVDC Light Modeling in PSLF

Development focus is on PSLF vscdc, vscdc1 models

EPCL interface via vscdc1[@mx].ed, vscdc1[@mx].eq, vscdc1[@mx].angle (when phase reactor impedance is included)


HVDC Light Model Benchmarking


HVDC Light Dynamic Performance


HVDC Light Dynamic Performance

P

Q

VA

VB

VC


ABB HVDC Model Availability (Detailed Models)

* Modifications may be required depending on specific configuration to be studied

PendingYesHVDC Light Passive Network Control

Yes*YesHVDC Light Vector Current Control

PendingYesHVDC CCC

Yes*YesHVDC Conventional

Available (Yes/No)Available (Yes/No)

PSLFPSS/EHVDC Type

Documents

WECC_HVDC_Task_Force-7-12-2011_03