Analysis And Research Of Subsynchronous Oscillation Caused By Series Compensation Device Applicatiaon

The source network load of the power system tends to be complicated and diversified.The ultra-high-voltage long-distance and large-capacity transmission network is being invested in China's power construction,continuously satisfying the large-capacity,long-distance,high-efficiency,low-loss,low-cost transmission of electric energy.Basic requirements.However,in actual operation,some of the traditional AC power grids in China have overloaded or approached the stability limit.This paper first studies the principle of series compensator and its application in high-voltage transmission lines.A detailed analysis of reactive power compensation and transient stability of transmission lines,At the same time,according to the example,the fault problem of series compensation device is analyzed.At the same time,in high-voltage transmission mode,the series capacitance compensation device may trigger the system.Synchronous resonance problems threaten unit safety and grid stability.Thus the principle of subsynchronous oscillation is further studied.Based on the IEEE subsynchronous oscillation standard research model,a subsynchronous oscillation model is established.With using PSCAD/EMTDC software to simulate,the curves of motor voltage and electromagnetic torque in subsynchronous oscillation are obtained,and the specific analysis is carried out.In order to avoid the possible subsynchronous oscillation,the working mechanism of the controllable series compensator TCSC is further studied and analyzed.And the theory of control method using TCSC to suppress subsynchronous resonance is proposed.A three-part closed-loop control system is established,which includes a tunable series-compensated transient stability control loop,a damped oscillation control loop,and a capacitor short-time overload capability and an overvoltage protection loop.And through the case study,the results show that by adjusting the PID parameters in the controller can effectively suppress the subsynchronous resonance in the system.