Neutral Voltage Comparison of Different Grounding Configurations and Calculation Methods in Multi-Grounded Low Voltage Network

Abstract

The steady growth in distributed generation brings more and more attention to low voltage (LV) distribution networks. Therefore, a good model is important to study these trends, especially with local regulation. Grounding the neutral line at multiple points along the network is a common practice in many European countries influencing neutral currents and voltages. Modelling grounding current had been of little interest at network planning and operation before, with only passive consumers. However, with the growing number of smart equipment, it becomes an overlooked, yet important issue. This equipment usually rely on local measurements and regulates accordingly. Given that most of the LV equipment uses single-phase connection, the neutral voltage is an important issue. Yet few papers study the neutral line behaviour and often overlook the effect of grounding. This article studies the effect of different grounding configurations on neutral voltages, and compares it with one of the most commonly used calculation method in literature that incorporates groundings. The differences are large enough to adversely affect local regulation.