Influence of neutral grounding method on voltage unbalance in 10 kV network with cable lines and overhead lines

The paper presents the results of experimental and computational investigations of power quality in the 10 kV network with different types of neutral grounding. It is shown that parameters of equipment, connected to the neutral point, have a significant impact on power quality in the field of voltage unbalance, up to deviation from standard values. The area of proper power quality in the field of zero sequence voltage unbalance for 10 kV network is determined. It depends on the ratio of overhead lines and cable lines capacitive current, on the type of neutral grounding. It is found out that power quality in the field of zero sequence voltage unbalance may be significantly improved by connection of additional resistance into a zero sequence circuit of the network.