ungrounded system

For an ungrounded neutral low voltage power system in mine, its insulance ( r), capacitance ( C) and leakage resistance ( R) to the ground are three important parameters in determining the zero sequence voltage.

对于中性点不接地的矿井低压电网，其对地绝缘电阻r，电容C和漏电电阻R，是决定零序电压的3个重要参数。

It is difficult fo select wire when there be single phase grounded fault in neutral point ungrounded system.

中性点不接地系统发生单相接地故障时，信号微弱，不易选线，对于谐振接地系统选线更加困难。

When there are system failures or lightnings, high-magnitude overvoltages will occur on these ungrounded neutrals.

当系统发生故障或者雷电波入侵时, 这些不接地变压器中性点上会出现幅值较高的过电压.

By MATLAB, the transient process of TV in ungrounded power system is simulated, both in normal service or in some kinds of grounding fault conditions. This paper discusses the magnetizing inrush current flowing through TV and the abnormal overvoltage of opened delta-winding.

用MATLAB软件仿真研究了中性点不接地系统中电磁式电压互感器在系统正常和接地故障运行的全过程，分析了TV励磁涌流造成熔丝熔断的规律性及开口三角绕组电压异常的原因。