Research On SVC Control Strategy In Voltage Stability Of Power System

The large-scale construction and operation of China's power grid,especially after the implementation of the program of "sending electricity from the west to the east,and the north and the south assist each other" in our country,has provided an important guarantee for industrial and agricultural production and living activities.The following issue,voltage stability,plays a key role in the health of power system.In this paper,PSACD software was used to model the 35 k V static reactive power compensation device installed in 220 k V substation of Xiaoying.The load-oriented control strategy was used to improve the controller to achieve the purpose of voltage stability of the system through SVC.The SVC control system balances the three phases respectively according to the principle of Steimetz,and then uses the instantaneous reactive power theory to calculate the reactive power rapidly,and obtains the values of compensation admittance.The TCR firing angle signal is obtained by the linearized process of compensating admittance.The inductive reactive power outputs from the reactor in the TCR is controlled to compensate the system.The voltage detected by the system is fed back to the voltage signal comparison module to compare with the reference voltage to control the SVC switching and calculate the admittance increment.After nonlinearly discretizing the admittance increment and the maximum firing angle and operations of addition and subtraction,the “most admittance” is derived;the compensation for admittance constraints is achieved.It is based on the control method mentioned above to optimize the system compensation which ends until the grid voltage is infinitely close to or even equal to the ideal voltage.It will not only make the voltage stable,but also improve the power factor.The paper also verifies whether the system can maintain the grid voltage and return to the steady-state voltage level after the removal of large disturbance.Finally,simulation and experimental verification are carried out to observe the changes of voltage,reactive power,power factor and firing angle before and after SVC compensation.It is concluded that the control strategy designed in this paper can theoretically meet the voltage stability of small battalion substation.