At present, some of the projects facing the market are transformation projects, which generally replace the original products. Most of the reasons are that the small current grounding line selection device was installed in the early stage of plant construction. After more than 10 years of operation, the equipment is seriously aged and often fails. It is unable to judge the grounding fault operation of the small current grounding system normally, which poses a threat to the safe operation of the equipment.

Because the current products are updated quickly and have been greatly upgraded in algorithm and hardware, the reliability of the original small current grounding line selection is not high, which often leads to protection misoperation, the configuration of its own printer is unstable, and it is difficult to record data normally. These are objective factors that can not be ignored.

On the basis of big data and strong computing power, the current small current grounding line selection device adopts steady-state algorithm + transient algorithm, line selection learning algorithm, combined with effective domain line selection technology and verified by "physical reality experimental system", which can accurately distinguish various complex grounding fault types such as metal grounding, transition resistance grounding and intermittent arc grounding. The device is characterized by the grounding mode of ungrounded neutral point, arc suppression coil grounding and resistance grounding. The adaptive line selection algorithm is adopted to improve the accuracy of line selection and avoid false automation. A device integrating line selection and protection.