35kV系统接地变压器不同接入方式的保护分析

Analysis on the Protection of 35 kV Grounding Transformer with Different Connection Modes

随着上海中心城区将架空线改为电缆线路,220 kV变电站的35 kV系统由原消弧线圈接地改为电阻接地。介绍了小电阻接地系统的接地变压器接于不同位置时的接地电流值和故障电流的特征,分析了零序电流保护范围的不同。

With the overhead power lines are changed to underground cable lines in downtown Shanghai, the grounding mode of 35 kV system with arc-extinguishing coil in 220 kV substation should be changed to resistance grounding. The grounding current value, fault current feature of the small resistance grounding system and ranges of zero sequence current protection when grounding transformer is connected to different position are analyzed.