Overcurrent Protection from Earth Faults Based on Higher Harmonics for Compensated 6- to 10-kV Cable Networks

Application of WAMPAC principles in distribution networks

“…Another direction for localizing faults in such networks involves measuring harmonics in zero sequence current and voltage. There are studies that confirm that distribution networks have significant harmonic components in the zero sequence circuit [17]. As we noted earlier, methods that involve measuring harmonics require the development of special filters.…”

“…Currently, there are several main methods for localizing SGF in medium voltage networks [16][17]. An urgent task is to develop new methods for networks with partial or full compensation of ground fault current.…”

“…A network with an isolated neutral makes it possible to implement maximum current and current directional SGF protection [17]. This is because in such a network the capacitive current of undamaged phases during a ground fault is directed to the fault location, so we can select the settings according to the theoretical values of the capacitive currents of the feeders.…”

“…Expressions ( 1) -( 4) are valid for a network with an isolated neutral and do not correspond to a network with compensation of the SGF current. In this case, we can use the active or harmonic components of the zero sequence current to identify the faulty feeder [17]. However, a network with full SGF current compensation allows only transient measurements to be used [16].…”