Multi-Line Flexible Alternating Current Transmission System (FACTS) Controller for Transient Stability Analysis of a Multi-Machine Power System Network

A considerable progress has been achieved in transi ent stability analysis (TSA) with various FACTS control lers. But, all these controllers are associated with single transm ission line. This paper is intended to discuss a new approach i.e. a multi-line FACTS controller which is interline power flow controller (IPFC) for TSA of a multi-machine power system network. A mathematical model of IPFC, termed as power injection model (PIM) presented and this model is incorporated in Newton-Raphson (NR) power flow algorithm. Then, the reduced admittance matrix of a multi-machine power system network for a three phase fault withou t and with IPFC is obtained which is required to draw the machine s wing curves. A general approach based on L-index has also been dis cussed to find the best location of IPFC to reduce the proximity t o instability of a power system. Numerical results are carried out on two test systems namely, 6-bus and 11-bus systems. A program in MATLAB has been written to plot the variation of generator rot or angle and speed difference curves without and with IPFC for TSA and also a simple approach has been presented to evaluate critical cl earing time for test systems. The results obtained without and with IPFC are compared and discussed. Keywords—Flexible alternating current transmission system (FACTS), first swing stability, interline power flo w controller (IPFC), power injection model (PIM).