关于有源配电网接地方式的探讨

Discussion about Grounding Mode of Active Distribution Networks

中性点接地方式选择是配电系统安全经济运行的基础问题,常规配电网中各种接地方式的技术特点已有明确结论,有效接地和非有效接地均有广泛应用。对于分布式电源(DER)大量接入的有源配电网,其接地方式将由主网和DER共同决定。且在DER并网与脱网不同运行状态、故障后主网保护与反孤岛保护等不同处理阶段中,系统接地方式可能存在转换,给故障电流、过电压以及衍生的供电可靠性、人身安全带来更为复杂的问题,有源配电网的中性点接地方式选择问题需要重新审视。

The selection of neutral grounding mode is a basic problem in distribution systems, which is related to the safe and economic operation. For conventional distribution network, technical characteristics of all kinds of grounding modes are clear, and both effective and non-effective grounding modes are widely used all around the world. But for active distribution network （ADN） which contains a great number of DERs, the neutral grounding mode is decided by the grounding modes of both main network and DERs. And grounding mode transformation may take place in different operating states of DERs （including grid-connecting state and off-grid state） and in single-phase ground fault handling process, which will bring more complex problems to ground fault currents, overvoltage, even power supply reliability and personal security. So the selection of neutral grounding mode in ADN needs to be re-examined.