When choosing the small current grounding line selection device, users should adopt the corresponding principle line selection equipment according to their own field conditions and actual needs. There are about dozens of small current grounding line selection device manufacturers in China, but there are not many enterprises with real R & D strength, and the product quality is also uneven. Many users often pay attention to price but not quality when purchasing. Therefore, users should choose manufacturers with excellent quality and excellent after-sales service, and strictly implement relevant technical regulations in equipment selection.

If conditions permit, it can also aim at the EMC performance of small current grounding line selection device. The insulation performance, mechanical and temperature effects shall be inspected according to the relay protection industry standards, and the manufacturer shall show relevant inspection reports to ensure the quality of the device.

In the electrical installation stage, the polarity of all zero sequence current transformers of small current grounding system should be consistent, and the secondary side should not be open circuit, and there should be a grounding point. The electrical characteristics of the zero sequence current transformer on the unified site shall be basically the same, and the zero sequence current transformer with the same brand or special matching with the small current grounding line selection device can be selected. Ensure the zero sequence voltage polarity of the opening triangle of the zero sequence current transformer is correct, and avoid the event that the small current grounding line selection device cannot correctly select the line because of the reverse polarity of the voltage transformer.

In addition, the substation operators on duty need to strengthen the patrol work of the small current grounding line selection device, and regularly check and test to ensure that the small current grounding line selection is in good condition and timely report the defects. During the inspection, check that the indication of each signal lamp is correct, the indication of power indicator is correct; the lead terminal is in good contact, the connector is not loose, and each connecting lead is not heated or discolored; the LCD is normal, whether there is fault and abnormal message display, etc. If any abnormal condition is found in the device, it should be handled at the first time to ensure the normal operation of the device. Make full use of the opportunity of equipment outage to check the relevant secondary circuit, and constantly summarize the operation experience and accumulate maintenance skills in daily work.