Optimal parameters of UPFC for power flow

Abstract

Unified power flow controller (UPFC) is a versatile flexible AC transmission system (FACTS) controller which can be used for voltage and power flow control. In some situations such as transient stability control, it is required to maximize and minimize the power flow on certain transmission lines. Since UPFC has three independent variables, the values of these for optimal power flow are not obvious. In this paper, Kuhn-Tucker conditions are used to obtain global optimal values of the variables of UPFC, which is located at the midpoint of a lossless symmetrical line.