Research On Modeling And Simulation Of STATCOM

Static Synchronous Compensator (STATCOM) is an important member of Flexible AC Transmission System (FACTS). Comparing with traditional reactive power compensation devices, it has many advantages, such as fast acting, low harmonic content, small floor area, more ideal output characteristics, etc. This dissertation studies modeling and simulation of STATCOM, based on Advanced Digital Power System Simulator (ADPSS), which is developed by China Electric Power Research Institute (CEPRI).Using User-Defined (UD) modeling function of electromagnetic transient simulation program in ADPSS, the dissertation develops a three-level STATCOM electromagnetic transient model which is similar to the STATCOM model in Electro-Magnetic Transients Program (EMTP). The correctness of STATCOM model is verified by comparing with the simulation results of EMTP. Taking into account the problems of neutral-point balancing algorithm used in the STATCOM model, a new three-level voltage deviation between two capacitors hysteresis-band control algorithm is proposed. Simulation results show that the proposed algorithm can eliminate the voltage deviation effectively.Electromagnetic transient simulation program in ADPSS is a fixed time-step simulation program. Switching delay will appear when the switching event occurs between two calculation cycles of the program. The dissertation improves the switch pulse triggering turn-on algorithm applying RTDS s improved firing algorithm. Moreover, the switch pulse triggering turn-off compensation algorithm is proposed. The effectiveness of the algorithms is verified by applying the algorithms to the simulation of TCSC model and STATCOM model.Based on the two-generators to a load system, the ability of STATCOM to improving voltage stability and damping power oscillation is analyzed and the conclusion that voltage controlling and power oscillation damping are contradictory is verified. Electromagnetic transient simulation, electromechanical transient simulation, and electromagnetic-electromechanical transient hybrid simulation are performed on the system without and with STATCOM. Simulation results are compared to verify the correctness of the hybrid simulation and obtain the conclusion that utilizing the hybrid simulation can accurately analyze characteristics of STATCOM. Hybrid simulations are performed when STATCOM is installed at different locations in Northeast Grid. Simulation results show that STATCOM can improve dynamic characteristics and transient stability of Northeast Grid. By comparing simulation results of STATCOM installed at different locations, the conclusion that STATCOM installed in the region where the reactive power is insufficient has the best ability to supporting transient voltage is confirmed.