When a single-phase ground fault occurs in a power system where the neutral point is not grounded (or is grounded via an arc suppression coil, or via a high-resistance grounding method), quickly identify which line the problem is on. (Because the increase in phase voltage caused by this fault poses a great threat to the insulation performance of the system, the faulty line must be quickly detected and eliminated.)
Another: The small current grounding line selection technology is developed by North China Electric Power University Professor Yang Yihan’s invention (patent).