利用中性点电阻削弱变压器励磁涌流

提出了一种简单且经济的削弱空载合闸变压器励磁涌流的新方法：在变压器中性点串入一电阻,三相延时合空载变压器.通过对该方法下涌流峰值随中性点电阻值变化的曲线进行理论分析,给出了最佳电阻值的表达式.该方法只使用一个电阻,但抑制效果类似于在三相线路中分别串联电阻的方法,且对合闸时间没有很精确的要求.仿真和动模实验结果都验证了该方法的有效性.

New Method for Mitigating Magnetic Inrush Current of Transformer by Neutral Grounding Resistor

This paper presents a new, simple and economical method to reduce magnetic inrush current caused by transformer energizing. The method uses a grounding resistor connected at the transformer neutral point and delayed energization of each phase of the transformer, The characteristics of peak inrush currents affected by the neutral resistor are analyzed and the formula for obtaining the optimal value of the neutral resistor is given. The method proposed has been tested by experimental simulation, The experimental results show that the new method has a performance similar to that of the resistor pre-insertion scheme, but it will be much less expensive since there is only one resistor involved. The level of the magnetic inrush current reduction depends on the value of the neutral resistance and the transformer parameters.