When there are many outgoing cabinets in the switch cabinet or distribution room in the substation, there are many circuits. If there is a line fault, how can we quickly and accurately determine which line has the fault? At this time, we need to judge the small current grounding line selection device to select a faulty line.

When single-phase grounding fault occurs in small current grounding system, the device has the function of automatic alarm and accurate search for fault line. It can be used not only for the transformation of old power plants and substations, but also for the construction of new power plants and substations, directly forming a comprehensive automation system.

There are many monitoring channels for small current grounding line selection, which can monitor the grounding condition of 60 outgoing lines at the same time; it is easy to use, and can be put into use without complicated configuration; it has a new modular circuit design, which basically does not need on-site maintenance after the device is put into operation; it has high reliability, and adopts foreign advanced high-speed DSP chip and CMOS industrial chip, with unique design, It has the characteristics of strong anti-interference ability, software and hardware redundancy, fast operation speed and low power consumption; it can sample rapidly, with high density and high speed, and complete data acquisition of all channels in one cycle; the communication interface can be configured with RS232C interface, RS485 interface, RS422 interface and Ethernet interface, which is suitable for unattended substation or integrated automation equipment; it has powerful information storage function, The fault record information can recall 500 times of grounding faults through LCD display, and the information will not be lost after the device is powered down.

Nevertheless, in order to more accurately analyze and judge the fault line in the project, in the actual design and application, users are also advised to buy the small current grounding line selection device and zero sequence current transformer from the same manufacturer, because the equipment produced by the same manufacturer has strong stability and better compatibility. Secondly, high-precision zero sequence current transformer should be selected as far as possible. Because the selection of high-precision zero sequence current transformer can ensure to improve the accuracy of line selection.