电压互感器三相励磁特性对铁磁谐振的影响

Influence of three phases′ excitation characteristics of PT on ferroresonance

利用通用的电磁暂态计算程序EMTP,对10kV中性点不接地系统中电磁式电压互感器(PT)饱和引起的铁磁谐振过电压进行了仿真计算。通过三相PT对称和不对称两种情况下的计算,得到互感器三相励磁特性对铁磁谐振的影响。计算表明,系统中三相PT励磁特性不相同非常有利于谐振发生。

The ferroresonance overvoltage, which results from the electromagnetic potential transformer in the 10 kV system with neutral point unearthed, is simulated and studied by the electro-magnetic transient program (EMTP). Through the simulations of three phases under the conditions of PT symmetric and asymmetric, the effect of excitation characteristics of three phases′ PT on ferroresonance is concluded. The results indicate that the difference of the three phases′ excitation characteristics of PT makes the ferroresonance very easy to occur.