基于注入法的接地相辨识

传统的接地相判别方法是在忽略电网不对称的前提下进行判别的,当发生在一定范围内的高阻接地故障时,传统判据失效。针对这一局限性,提出了一种基于注入法的新型接地相判别方法,当电网发生单相接地故障时,向电网注入某一电流,用来消除电网不对称度,使电网中性点电压仅为由故障相引起的中性点位移电压,通过分析注入电流后的中性点电压的相位角,得出中性点电压相位角随过渡电阻的变化范围,可知不同相发生接地故障时中性点电压相位角随过渡电阻的变化范围也不相同。因此,可利用注入电流后的中性点电压的相位角的变化范围来实现故障相的辨识,尤其是高阻接地相判别,其可行性得到了仿真的验证。

The Detection of Grounding Phase Based on The Method of Injecting Current

The method of traditional grounding phase detection is conducted under the premise of ignoring the asymmetry of the grid. When a single-phase to ground fault via high resistance occurs in the distribution network, the traditional criterion is futile. In response to this limitation, this paper presents a new method of traditional grounding phase detection based on the method of injecting current. When a single-phase to ground fault occurs, a special current injected into the grid, to eliminate the asymmetry of the distribution network. Then the neutral point voltage is only caused by the grounding phase. By analyzing the phase angle of neutral point voltage after injecting this special current, the paper draw the neutral point voltage phase angle varies with the transition resistance. It can be seen that different phase takes place a single-phase to ground fault the neutral point voltage phase angle varies with the transition resistance is not the same That is to say the range of the phase angle of neutral point voltage after injecting the current can be used to detect the grounding phase, especially the high resistance grounding fault detection. Its feasibility has been verified by simulation.