带辅助控制的TCR型SVC控制策略研究

Research on TCR Type SVC Control Strategy with Auxiliary Control

针对TCR型SVC稳态运行时为了维持电压稳定需要不断调整输出而造成损耗较多的问题,在基本电压控制策略中加入了电压死区辅助控制:在电压允许误差范围内锁定SVC,在范围外则释放SVC调节电压至范围内。在此基础上,为了能更有效地利用SVC有限的额定容量,对应设计了可根据电压大小而变化的电压参考值,确保SVC输出一直处于可调节范围内且可具有较多的无功储备。针对当系统中含有2次谐波电压分量时会导致TCR电流中产生大量的直流分量问题,加入了TCR平衡辅助控制:通过将快速傅里叶变换和PI调节相结合调制触发角使反并联的晶闸管达到在正方向和负方向的导通时间不相同,将直流电流分量减小到零,保证装置的安全运行。仿真结果表明上述辅助控制具有可行性和有效性。

To solve the problem of high loss caused by constant adjustment of output in order to maintain the stability of the voltage during the steady-state operation of the thyristor controlled reactor(TCR)type static var compensator(SVC),the voltage dead zone auxiliary control was added to the basic voltage control strategy.That is,when the voltage was within the allowable error range,the SVC was locked,and outside the range,the SVC was released to adjust the voltage to the range.On this basis,in order to make more effective use of the limited rated capacity of SVC,a voltage reference value that could be changed according to the voltage was correspondingly designed to ensure that the SVC output was always within the adjustable range and could have major reactive power reserves.Aiming at the problem that a large number of DC components would be generated in the TCR current when the system contains second harmonic voltage components,the TCR balance auxiliary control was added.That is,by combining the fast Fourier transform and PI adjustment to modulate the firing angle,the anti-parallel thyristors could achieve different conduction times in the positive and negative directions,and the DC current component could be reduced to zero to ensure safe operation of the device.The simulation results show that the above auxiliary control is feasible and effective.