SVC接入侧过电压保护的改进控制策略研究

Research on Improved Control Strategy for Overvoltage Protection of SVC Access Side

针对输电系统中装设于变压器低压侧的大容量SVC在系统处于重载运行工况时会出现过电压的问题,首先理论分析了SVC接入侧过电压的机理,然后指出了常规保护性限制策略的缺陷及其造成的问题,并在此基础上提出了SVC接入侧过电压保护的改进控制策略:即一方面使用比例积分控制替代常规的单纯积分控制,另一方面改变电压参考值使得SVC电压控制器输出的电纳参考值与限制器限幅后的最小电纳值相等,并且还增大SVC电压控制器的增益系数,从而可以快速而稳定地降低接入侧的过电压值。最后,在PSCAD/EMTDC中的实际算例仿真表明上述策略具有可行性和有效性。

Aiming at the problem that the large-capacity SVC installed on the low-voltage side of the transformer in the power transmission system may have an overvoltage when the system is under heavy-load operating conditions, the mechanism of SVC access side overvoltage is analyzed theoretically. Then the defects and problems of the conventional protective limiting strategy are pointed out. On this basis, an improved control strategy for overvoltage protection of SVC access side is proposed. On the one hand, the proportional integral control is used to replace the conventional simple integral control. On the other hand, changing the reference voltage value makes the reference susceptance value output by the SVC voltage controller equal to the minimum susceptance value after limiting the amplitude of the limiter, and increases the gain factor of the SVC voltage controller, so that the overvoltage value of the access side can be reduced quickly and stably.Finally, the actual example simulation in PSCAD/EMTDC shows that the above strategy is feasible and effective.