变阻抗变压器过电压分析

Overvoltage Analysis of Variable Impedance Transformer

电力系统短路电流严重影响了变压器的安全可靠运行,为限制变压器的短路电流,提出了一种新型的变阻抗变压器,该新型变压器能实现阻抗的自主调节,保障了限流效果的同时还兼顾了经济性。文中介绍了变阻抗变压器的结构及原理,利用PSCAD仿真软件分析了变阻抗变压器过电压的特性及抑制方法。研究结果表明:变阻抗变压器阻抗调节过程中会产生高频高幅值的暂态过电压,在限流电抗器两端并联电容器能有效地抑制暂态过电压的幅值及频率,并能使电抗器绕组电压均匀分布。变阻抗变压器的投入使用有利于提高电力系统运行的安全可靠性。

Short circuit current of power system seriously affects the safe and reliable operation of the transformer. In order to limit the short-circuit current of the transformer, variable impedance transformer is proposed. This transformer can reduce the impact of short-circuit current and also take the economy into account. The structure and principle of variable impedance transformer are introduced, PSCAD simulation software is used to analyze the distribution of overvoltage of variable impedance transformer. Researches indicate that the transient overvoltage would be generated in the process of impedance adjustment, the amplitude and frequency of transient overvoltage could be suppressed effectively with the existence of shunt capacitor, and the voltage of the reactor winding could be distributed evenly because of the shunt capacitor. The use of variable impedance transformer is benefit to im- prove the security and reliability of power system.