Abstract: The penetration rate of Flexible Alternating Current Transmission System(FACTS) is increasing day by day as new power systems are constructed, which leads to more complicated system structures and more serious steady-state security problems. The paper, based on the equivalent power injection method, makes the Thyristor Controlled Series Compensation(TCSC) equivalent to two-node injected power, and obtains a steady-state security region model considering the influence of multiple TCSCs according to the DC power flow model. First, the generalized volume index of steady-state security region is defined to evaluate the steady-state security of the system. Second, the paper, taking the TCSC installation position and its equivalent reactance as optimization variables and the maximization of security region generalized volume index as the objective function, constructs a coordinated optimization model of multiple TCSCs and solves it by the modified plant growth simulation algorithm.Finally, the IEEE 10-machine 39-node system is taken as an example to analyze the proposed method. The results show that this method can significantly improve the efficiency of steady-state security region construction. Moreover, it can guarantee the safe and stable operation of power grids to the maximum extent on the basis of improving the transmission capacity of the system.

    Key words: flexible alternating current transmission system;t hyristor controlled series compensation;s teady-state security region;g eneralized volume index