The majority of loads in stability analysis are modeled as static. Choice o
f load representation characteristics greatly influences stability study re
sults, as well as conventional power system controller design. But it is ve
ry hard to identify the exact proportion of load composition. Such inaccura
cy may result in poor or even degrading control influence. In this paper, w
e represent the static load as the composition of constant power, constant
current, and constant impedance. We then formulate the load representation
inaccuracy into structured uncertainty. Finally we employ the structured si
ngular value (mu) analysis and synthesis, which is a newly developed robust
control method, to design and analyze the robust controller for TCSC. This
controller has low order and can work well under different static load mod
eling. This controller design scheme is practical in the sense that it can
adapt to a wide range of system parameters without significant increase in
complexity. (C) 2000 Elsevier Science S.A. All rights reserved.