Resistive Neutral Grounding Device with Increased Thermal Withstand Capability

Shifting medium voltage networks intended for operation in the resistive neutral grounding mode is one of the most promising ways to enhance the reliability power supply systems. However, along with the advantages of this network neutral grounding arrangement method, such as achieving lower overvoltage ratios during a short-circuit ground fault due to the use of high-ohmic resistors and better selectivity of simple current protections in case of using low-ohmic resistors, low thermal withstand capability of the grounding resistors is a serious obstacle for their wide application in the existing networks. The article considers the design of a resistive neutral grounding device featuring an increased thermal withstand capability. The proposed resistive grounding device will be able to operate under the conditions of a single-phase ground fault for almost an unlimited period of time. As a result, more reliable operation of the network will be achieved, and a longer period of time will be available for the personnel to locate the fault. The results obtained from mathematical simulation of the device temperature field carried out using the Comsol Multiphysics software package for the case when the fault current flows through the device are presented.