考虑谐振过电压的消弧线圈接地系统阻尼参数整定算法

Setting principle for the damping resistance in the arc suppression coil system based on eliminating resonance over-voltage

目前35kV及10kV配电网系统的中性点接地方式以消弧线圈接地方式为主,这种系统在正常运行时其等值电感和系统对地电容及阻尼电阻组成了RLC串联回路,在上述系统参量不匹配时,易引发系统参数谐振过电压使得系统零序电压越限,给调度运行部门造成接地故障的假象特征。结合实际配电网运行中的过电压现象,对消弧线圈系统运行方式借助理论工具从本质上进行剖析与推倒,深刻揭示了串联谐振问题产生的根源,并推导出阻尼电阻取值范围的一般公式表达。根据该整定计算方法对阻尼参数进行修正后,异常现象得以有效抑制,其整定原则对生产实际具有普遍适用性。

Nowadays, the arc suppression coil grounding method is prevalent in distribution systems. Under normal operating mode, the inductance of arc suppression coil, the equivalent capacitance to the ground and the damping resistance constitute one RLC series circuit, so the resonance over-voltage in the system will often occur if the three mentioned parameters can not be matched. The above series resonance results in excessive zero sequence voltage, which is characteristic of ground fault and the dispatchers can be misled in the course of fauh judging. The investigation and theoretical analysis was carried out for the abnormal phenomenon, and the essences of series resonance were fully comprehended and grasped, the damping resistance＇ s value interval was expressed in the mathematic form. The parameter of damping resistance is revised according to the mentioned setting principle, therefore former over-voltage is constrained effectively during the daily operation, which takes on a remarkable significance in reality.