Since the development of small current grounding line selection device, there have been various disputes. There are good and bad. The accuracy of line selection of small current grounding line selection device is difficult to ensure. Judging from the state information of single-phase grounding and normal operation of small current system, it seems very easy to determine the fault line, but this is not the case.

        Due to the complex and changeable grounding conditions, each algorithm has its applicable service conditions. The more typical the conditions are, the higher the line selection accuracy of the corresponding algorithm. Therefore, the judgment of fault type has a key impact on the accuracy of line selection results. Therefore, the selection of grounding fault type and line selection algorithm needs to be arranged as a whole.

        The single-phase grounding fault line selection methods of distribution network using transient voltage and current signals are mostly based on the comparison of current or voltage signals in a fixed frequency band, and the accuracy of small current grounding line selection is improved.

        Our company's industrial computer small current grounding line selection device has accurate sampling, fast operation speed, strong grounding fault screening ability and wide adaptability to system changes. High precision zero sequence current transformer is used to solve the problem of single-phase grounding fault in small current system.