The main function of small current grounding line selection device is to check whether there is single-phase grounding fault in power system. The fault signal collected by the small current grounding line selection device can be processed by digital filtering, and the fault information can be filtered by comparing the abnormality of the neutral point connection mode. At the same time, various algorithms are used to check, and then judge whether the system has fault and the specific line of the fault.

Basic functions of small current grounding line selection device:

Line selection function: in case of single-phase grounding fault in small current grounding system, the line selection shall be accurate and the grounding line or bus number shall be displayed. When ferromagnetic resonance occurs, there is no false alarm or false operation;

Fault wave recording function: it shall provide the accident report of electric quantity startup of the device, including at least one cycle before the fault and five cycles after the fault. Fault information can be easily analyzed and extracted;

Remote maintenance function: it can communicate with the master station for remote maintenance of the equipment;

Event record: it can memorize the grounding information for at least 20 times. The grounding information should include the result of each line selection, the starting and ending time of grounding, etc. the data information saved after the power failure of the device will not be lost.

Grounding signal output: output signal after single-phase grounding, and return automatically after grounding disappears;

Signal reset: automatic reset when grounding disappears;

Communication function: the device should be equipped with communication interface to meet the communication requirements of automation system, transmit grounding information to remote control equipment or upper computer, device action information and receive timing command, etc;

Setting function: the parameters and setting values of the device can be set manually or remotely, such as: bus number, occurrence number, line number, starting voltage (current), etc;

Self check function: small current grounding line selection should have online automatic detection function. During normal operation, when a single component in the device is damaged, it should be able to alarm and lock the device.