a quick solution to optimal coordinated voltage control based on dimension-reduction of power system through modified ward-pv

Voltage control and voltage stability are the most important issues in the power system. the purpose of this paper is to investigate the emergency voltage control in power systems. one of the most important proposed methods to solve this issue is optimal coordinated voltage control (ocvc), which is based on the model predictive control (mpc). time limitations for preventing voltage collapse is the most critical constraint to solve an ocvc problem. in this paper, the modified ward-pv will be proposed to reduce the dimension of the power system and consequently, the speed of solving problem is increased. in this method, immediately after occurrence a fault, the power system is partitioned to into three subsystems by spectral graph partitioning method. partitioning is based on reactive power flow through the lines. the subsystems, which are far from fault, will be replaced by the reduced model. this method will drastically reduce the number of system equations and will boost the speed of solving problem. the simulations results obtained on new england ieee 39-bus system reveals that the proposed method acts more precise than dimension reduction of power system based on linearization of external subsystems, but the speed of solving problem decrease.