Title :
System stability improvement through optimal control allocation in voltage source converter-based high-voltage direct current links
Author :
Pipelzadeh, Yousef ; Chaudhuri, N.R. ; Chaudhuri, Balarko ; Green, T.C.
Author_Institution :
Dept. of Electr. & Electron. Eng., Imperial Coll. London, London, UK
fDate :
9/1/2012 12:00:00 AM
Abstract :
Control of both active and reactive power in voltage source converter (VSC)-based high-voltage direct current (HVDC) links could be very effective for system stability improvement. The challenge, however, is to properly allocate the overall control duty among the available control variables in order to minimise the total control effort and hence allow use of less expensive converters (actuators). Here relative gain array and residue analysis are used to identify the most appropriate control loops avoiding possible interactions. Optimal allocation of the secondary control duty between the two ends of the VSC HVDC link is demonstrated. Active and reactive power modulation at the rectifier end, in a certain proportion, turns out to be most effective. Two scenarios, with normal and heavy loading conditions, are considered to justify the generality of the conclusions. Subspace-based multi-input-multi-output system identification is used to estimate and validate linearised state-space models through pseudo random binary sequence probing. Linear analysis is substantiated with non-linear simulations in DIgSILENT PowerFactory with detailed representation of HVDC links.
Keywords :
HVDC power convertors; MIMO systems; binary sequences; optimal control; random sequences; reactive power control; rectifying circuits; stability; state-space methods; DIgSILENT PowerFactory simulation; HVDC link; VSC; active power control; active power modulation; actuator; control loop; high-voltage direct current link; linear analysis; linearised state-space model; nonlinear simulation; optimal control allocation; pseudorandom binary sequence probing; reactive power Control; reactive power modulation; rectifier; relative gain array; residue analysis; secondary control duty; subspace-based multiinput-multioutput system identification; system stability improvement; voltage source converter;
Journal_Title :
Generation, Transmission & Distribution, IET
DOI :
10.1049/iet-gtd.2011.0828