长沙城区10kV配网中性点接地方式的探讨

根据目前长沙城区10 kV配网的特点,结合实际情况,对长沙城区10 kV配网现有接地方式(中性点经消弧线圈接地方式)进行分析,发现部分消弧线圈容量已经不能满足实际要求.具体表现为系统发生单相瞬时接地故障时,电弧不易熄灭,从而演变成相间短路,甚至多线短路等情况.通过分析研究,认为应将长沙城区10 kV配网部分不接地系统改为中性点经小电阻接地方式,其优点是当发生单相接地故障后,由继电保护动作,切断故障,从而保证配网的安全运行.

Research on Neutral Grounding Mode in 10 kV Distribution Network in Changsha District

While capacitive current in 10KV distribution network in changsha district increases rapidly,the widespread neutral grounding mode via arc suppressing coil is not adequately suited to the purpose.Among practical accidents related to the incapacity of the grounding mode the biggest problem is that when one-phase-to-ground faults are detected arc extinction is difficult to complete and interface short circuit even poly-phase short circuit occurs instead.In this paper a neutral grounding mode via small resistance in changsha distribution network which can offer innovative solution for short-circuit environments is introduced.Concrete capacitive current calculation is described.Current district situation is analyzed.Finally it is proposed that non-grounding subsystem within the distribution network be replaced by neutral grounding with small resistance.The proposition will improve stability and validity of distribution network as it adopts relay protection for clearing ground faults to avoid potentially unacceptable damage.