高压内置变压器零序涌流特性研究

Research on zero-sequence inrush characteristic of high-voltage built-in transformer

变压器的零序涌流不再偏向于时间轴一侧,且二次和三次谐波含量更高。与普通结构变压器相比,高压内置变压器由于将高压侧内置,在结构参数上呈现互漏感较小而自漏感较大的特点。此外,高压内置变压器能够产生幅值更大,零序含有率更高且衰减较为缓慢的励磁涌流。通过仿真模拟了不同因素对涌流特性的影响,得到高压内置变压器更容易导致零序电流保护误动的结论,并根据实际经验给出了初步的应对方法。

The zero-sequence inrush of transformer is no longer biased on the side of the time axis,and its secondary and third harmonic contents are higher.Compared with ordinary structure transformer,the high-voltage built-in transformer has smaller mutual leakage inductance and larger self-leakage inductance in structure parameters because its high-voltage side nears the core.In addition,the high-voltage built-in transformer can produce larger amplitude,higher zero-sequence containing rate and slower attenuation of inrush current.By simulating the influence of different factors on inrush current characteristics,it is concluded that the high-voltage built-in transformer is more likely to cause zero-sequence current protection mal-operation is obtained,and the preliminary countermeasures are given according to practical experience.