Coordination of Damping Control in Transmission Networks with HVDC links
Author(s)
Pipelzadeh, Yousef
Type
Thesis
Abstract
The primary goal of this thesis is to investigate the small-signal stability of transmission
networks with wind generation and high voltage direct current (HVDC) transmission
integrated in them. The topic reflects a number of concerns of transmission network
operators in the U.K. and beyond over how stability is maintained as networks evolve.
Damping low frequency power oscillations using wide-area signals are illustrated
for both line commutated based current source converter (interchangeably referred as
LCC or CSC) and self commutated voltage sourced converter (VSC) based HVDC links
integrated within host AC networks. With VSC HVDC offering flexibility greater than
LCC HVDC in terms of modulating both active and reactive power, it was shown that
optimally allocating/sharing the control duty among the multiple control options that
exist within a VSC HVDC link, ensures that the overall control duty is reduced, and
hence, the dynamic ratings of the expensive converters is minimised.
An important consideration in the design of power oscillation damping (POD) controllers
is to ensure that the controller is robust across a range of practical operating conditions.
To achieve this, an analytical control design technique is introduced in which all
the control loops for a VSC HVDC link, are designed simultaneously in a multi-variable
framework. The method results in a set of decentralized, robust single-input-singleoutput
(SISO) controllers at the two ends of a VSC HVDC link, which ensures coordinated
control action and an acceptable performance level in the event of loss of a remote
feedback signal.
Damping contribution from remote offshore wind farms connected via VSC HVDC
is an important consideration for systems with high penetration of wind energy. The
effectiveness of coordinating the supplementary control of the wind farm and the onshore
HVDC converter is shown in terms of dynamic variations in wind farmreal power
output, DC link voltage and turbine speed.
Having examined the damping contribution, frequency support from offshore wind
farms is also explored. A method using appropriate droop control on the offshore and
onshore HVDC converters is proposed which enables offshore wind farms connected
through VSC HVDC link to contribute to system inertia and primary frequency control
without having to rely on remote communications. The effectiveness of the proposed
approaches is illustrated through detailed frequency domain analysis and extensive time-domain
simulation results in DIgSILENT PowerFactory on two test systems.
networks with wind generation and high voltage direct current (HVDC) transmission
integrated in them. The topic reflects a number of concerns of transmission network
operators in the U.K. and beyond over how stability is maintained as networks evolve.
Damping low frequency power oscillations using wide-area signals are illustrated
for both line commutated based current source converter (interchangeably referred as
LCC or CSC) and self commutated voltage sourced converter (VSC) based HVDC links
integrated within host AC networks. With VSC HVDC offering flexibility greater than
LCC HVDC in terms of modulating both active and reactive power, it was shown that
optimally allocating/sharing the control duty among the multiple control options that
exist within a VSC HVDC link, ensures that the overall control duty is reduced, and
hence, the dynamic ratings of the expensive converters is minimised.
An important consideration in the design of power oscillation damping (POD) controllers
is to ensure that the controller is robust across a range of practical operating conditions.
To achieve this, an analytical control design technique is introduced in which all
the control loops for a VSC HVDC link, are designed simultaneously in a multi-variable
framework. The method results in a set of decentralized, robust single-input-singleoutput
(SISO) controllers at the two ends of a VSC HVDC link, which ensures coordinated
control action and an acceptable performance level in the event of loss of a remote
feedback signal.
Damping contribution from remote offshore wind farms connected via VSC HVDC
is an important consideration for systems with high penetration of wind energy. The
effectiveness of coordinating the supplementary control of the wind farm and the onshore
HVDC converter is shown in terms of dynamic variations in wind farmreal power
output, DC link voltage and turbine speed.
Having examined the damping contribution, frequency support from offshore wind
farms is also explored. A method using appropriate droop control on the offshore and
onshore HVDC converters is proposed which enables offshore wind farms connected
through VSC HVDC link to contribute to system inertia and primary frequency control
without having to rely on remote communications. The effectiveness of the proposed
approaches is illustrated through detailed frequency domain analysis and extensive time-domain
simulation results in DIgSILENT PowerFactory on two test systems.
Date Issued
2012-05
Date Awarded
2012-08
Copyright Statement
Attribution NoDerivatives 4.0 International Licence (CC BY-ND)
Advisor
Chaudhuri, Balarko
Green, Tim
Sponsor
Power Networks Research Academy
Grant Number
EESC P21509
Publisher Department
Electrical and Electronic Engineering
Publisher Institution
Imperial College London
Qualification Level
Doctoral
Qualification Name
Doctor of Philosophy (PhD)