Corrective Control with Transient Assistive Measures: Value Assessment for Great Britain Transmission System

Abstract

In this paper, the efficacy and value of using correc-tive control supported by transient assistive measures (TAM) isquantified in terms of the cost savings due to less constrained oper-ation of the system. The example TAM is a rapid modulation of thepower order of the high-voltage direct current (HVDC) links in thesystem so as to improve transient stability during corrective con-trol. A sequential approach is used for the offline value assessment:a security constrained economic dispatch (SCED) module (masterproblem) determines the optimal generation dispatch, HVDC set-tings, and the corrective control actions to be used post-fault (gen-eration and demand curtailed) so as to minimize the operationalcosts while ensuring static security. The transient stability mod-ule (slave problem) assesses the dynamic stability for the operatingcondition set by the SCED and, if needed, applies appropriate TAMto maintain the system transiently stable. If this is not possible, themaster module uses a tighter set of security constraints to updatethe dispatch and other settings until the system can be stabilized. Acase-study on the Great Britain system is used to demonstrate thatcorrective control actions supported by TAM facilitate significantlyhigher pre-fault power transfers whilst maintaining N-2 security.