With the rapid development of market economy and the continuous improvement of people's living standards, people's requirements for the safety, comfort, practicality and other aspects of the living environment are also increasing. At the same time, the intelligent residential district has higher and higher requirements for power supply system, so the safety, comfort, functionality and development of the district must be considered in the initial design stage of power supply.

        In case of grounding fault of a power supply cable, the power supply department needs to cut off the power. Generally, the average time of power cut is 4-5 hours, which seriously affects the normal life of residents in the community. In fact, when a small current grounding fault occurs in the power supply cable, the fault current can reach 10A or less, which is still difficult to solve under the existing technical conditions, and a lot of time is wasted only in inspection and search.

        In order to reduce the power failure time and economic loss caused by power failure, a small current grounding line selection device can be installed. A small current grounding line selection device detection device is arranged on the main line of the distribution network, which can accurately indicate the grounding fault, upload the data to the main station, realize the rapid fault detection and positioning, quickly arrange emergency repair and restore the power supply.