我国广大农村用电，因地理位置、经济条件等诸多因素影响，一般采用单台配电变压器通过３８０／２２０ＶＴＴ型供电网络输送电能给用户的。这种供电网络在日常运行中，常发生下列故障：相间短路；中性线断线开路；配电变压器高压侧一相熔断器熔断；配电变压器低压侧一相熔... The vast majority of rural electricity in China, due to geographical location, economic conditions and many other factors, the general use of a single distribution transformer through the 380 / 220VTT-type power transmission network to the user. In the daily operation of this kind of power supply network, the following faults often occur: short-circuit between phases; open circuit of neutral line; fuse of one phase fuse on the high voltage side of distribution transformer;