Аннотация
The features of operation of the 6-10 kV distribution power grids, which are commonly utilized in the power supply systems of industrial enterprises and cities, are considered and analyzed. It is shown that cabling, high-voltage motors and instrument voltage transformers are very vulnerable to overvoltages. It is noted that the existing systems for limiting overvoltages and protecting against ground faults, using surge arresters, RC-dampers, arc suppressing reactors, the neutral resistors of power grids and relay protection, are characterized by a number of advantages, but are ineffective when used separately. The advantage of the combined system of overvoltage and ground fault protection for power grids is proven and shown, and the results of operational testing are the basis for practical use.