Single phase grounding fault is the most common fault type in small current grounding distribution network

but the on-site low current grounding line selection device is often difficult to meet the application requirements

affecting the rapid and accurate treatment of grounding fault. Considering that there are many low current grounding line selection manufacturers and various device forms

it is difficult to intuitively evaluate the line selection performance of different devices and make horizontal comparison

and there is no supporting basis for the selection and application of on-site line selection devices. Therefore

based on the real-time digital simulation system（RTDS）

this paper establishes a test platform for small-current grounding line selection device

and carries out parallel testing of different line selection devices. Through the same test under all-round fault scenarios

it provides strong support for the pilot application of small current line selection device.