Load frequency control of interconnected power systems with system constraints

Abstract

So far, researches in load frequency controls ( LFC) are involved in analysis of dynamic responses under normal conditions of the - interconnected power systems. In This research considers some system constraints (for example, one area fails to respond in a two-area interconnected system) and both steady state and dynamic responses are analyzed. Effects of control parameters B and K of the tie-line bias control strategy is studied for steady state and dynamic responses. It is shown that the tie-line bias control strategy is ineffective in regulating the frequency and it allows large steady state frequency deviations, although it yields desired steady state responses in normal conditions. A new cost optimization criterion is proposed which compromises both steady state and dynamic responses. Furthermore, we have investigated steady state and dynamic responses of proposed optimal control and variable structure system (VSS) designs for LFC systems which show much poorer dynamic system responses when one area fails to respond for a shortwhile compared to their performances in normal conditions and conventional LFC system design responses when one area fails to respond.