Study On TCSC Technology Suppressing Oscillations Of Power System

Thyristor controlled series compensation (TCSC) is an important member of flexible AC transmission system (FACTS) devices. It can compensate the inductive impedance of the transmission line, effectively improve the transmission power of the line to solve the problem of long-distance transmission, reduce the voltage differences and power angle differences caused by transmission lines and improve the power system stability. As the rapid response capability, it can also improve the dynamic stability, suppress the low-frequency resonance and sub-synchronous resonance.This paper firstly introduces the FACTS family members and classification, presents at home and abroad TCSC Researches and applications.Then analyzes the structure and working principle of the TCSC, deduces the mathematical model of the fundamental frequency impedance.Based on the analysis of TCSC suppressing low-frequency oscillation principles, this paper sets up the single machine infinite bus system in Simulink to study the effects of low-frequency oscillation damping controller on the inhibition of low-frequency oscillation. The principle of particle swarm optimization algorithm and its improved method were introduced in this paper and the improved particle swarm optimization algorithm is selected to optimize the control parameters to obtain the best control result.The principles of TCSC suppressing SSR are elaborated from different perspective. Using test signal method, the impact of TCSC installed capacity on sub-synchronous frequency electrical damping was studied by IEEE first benchmark model. According to the principles of the phase compensation, TCSC’s Additional multi-modes SSDC was designed which was testified by time domain simulation in PSCAD. The impedance step response and sub-synchronous oscillation damping effect were researched with different synchronous signal.A new method was proposed to reduce the role of electromechanical coupling which based on TCSC mixed compensation. It can reduce the energy exchange between mechanical and electrical systems. The imbalanced three-phase sub-synchronous frequency impedance was calculated considering TCSC firing angle impact. According to the principles of the phase compensation, single phase TCSC’s additional SSDC was designed to suppress SSR. TCSC’s firing angle and installation phase were studied to the effect on damping SSR. This method can save costs in practical engineering applications which was verified by time-domain simulation.