Abstract More comprehensive mathematical equations of TCSC circuit for any period (including the whole transient process from firing the thyristors to a steady state) and for the steady state relating to the voltages and currents of the capacitor, inductor and thyristor components are precisely developed by using Laplace transformation. And the accurate mathematical relationship between the fundamental impedance of TCSC and the firing angle of the thyristors is further derived by using Fourier analysis. The validity of the mathematical analysis is demonstrated by using the electro-magnetic transient program (EMTP) digital simulations. Furthermore, a whole model system for TCSC dynamic simulation test including the actual microprocessor-based control hardware is constructed to compare with and verify the mathematical analysis and EMTP simulation. The test results agree well with the analytical and simulation results and clarify the validity of the assumption that the line current keeps sinusoidal, which is adopted in both the mathematical analysis and the EMTP digital simulations.
Keywords series capacitor compensation flexible alternating current transmission system (FACTS) thyristor controlled series compensation (TCSC) electro-magnetic transient program (EMTP) dynamic simulation test
0 引言
晶闸管控制的串联电容补偿(TCSC)是灵活交流输电系统(FACTS)中重要的成员,又称为带有晶闸管控制阻抗的先进串联补偿(advanced series compensation,简称为ASC)。由于它具有潮流控制、阻尼线路功率振荡、提高电力系统暂态稳定和抑制次同步振荡(SSR)等多种功能[1~3],因此在电力系统中的应用潜力很大。在美国,含晶闸管控制的串联电容器工程已有3处投入运行。文献[4]仅推导稳态时TCSC回路中各元件的电压、电流公式,且并不完整(只能求解部分时间段内的电压、电流)。本文的重点是TCSC回路的数学分析。