不同10 kV接地系统的转供电运行方式分析

Analysis of Power Supply Operation Modes of Different 10 kV Grounding Systems

10 kV中压配电网中的变电站母线存在不接地、经智能型小电抗接地或小电阻直接接地等系统接地方式,各种接地方式在中压线路发生接地故障时的故障隔离方式及准确性不同。在故障停电或主网设备计划检修期间,不同10 kV接地系统的两个变电站的10 kV馈线间就会存在转供电的特殊运行方式,而小电抗接地与小电阻接地对接地故障的适应性不同,针对一次因运行方式安排不当导致中压配电线路接地故障事件扩大至整段10 kV母线失压事件开展故障原因分析,为实现故障影响范围更小及隔离故障效率更高,给出了转供电运行方式建议,对于中压配电网调度运行方式安排具有重要的参考意义。

The substation bus in the 10 kV distribution network is ungrounded,grounded through intelligent small reac‐tance or directly grounded through small resistance.The fault isolation modes and accuracy of various grounding modes are different in case of grounding fault of medium voltage line.During the period of power failure or planned mainte‐nance of main network equipment,there will inevitably be a special operation mode arrangement of power transfer be‐tween the 10 kV lines of two substations with different 10 kV grounding systems.The adaptability of small reactance grounding and small resistance grounding to ground fault is different.In this paper,the fault cause analysis is carried out for a ground fault event of medium voltage distribution line extended to the loss of voltage of the whole section of 10 kV bus due to improper operation mode arrangement.In order to achieve smaller fault influence range and higher fault isola‐tion efficiency,suggestions on the arrangement of switching power supply operation mode are given.It has important reference significance for the dispatching operation mode arrangement of medium voltage distribution network.