An assessment of the effectiveness of surge protection in a 10 kV cable distribution network

This article focuses on the efficient application for metal-oxide protective devices (MOPD) to limit overvoltages in 10 kV cable distribution networks. It presents an original method of mathematical modeling for the propagation of overvoltage waves in a cable network with MOPD. The method is based on the creation of a system of difference equations that link direct and reflected waves at the network nodes. The method allows for obtaining time dependencies of the voltage at any point in the network, the construction of maps of maximum overvoltages, and the risk of overvoltages with high magnitudes. A simulation of a cable network section was conducted to evaluate the effectiveness of installing MOPD at network nodes. The results showed that the greatest effect was achieved when MOPD was installed at nodes with a large number of outgoing cable lines. A comparison of the effectiveness of MOPDs with different current-voltage (V-I) characteristics and partial discharge (PD) inception voltage levels was also conducted. Devices with variable V-I characteristics demonstrate significantly greater efficiency in limiting overvoltages. The results can be used for optimizing the protection of 10 kV cable networks from overvoltages and increasing the reliability of power supplies.