ABSTRACT
Power system neutral grounding has been practiced since the beginning of power system development to hold the phase voltages stable with respect to ground. Power systems are always grounded through the system capacitance, even if the system neutral(s) is ungrounded. The grounding of many systems has been based on past experience, or opinion, or an extension to the grounding methods in existing installations. High-resistance (HR) grounding is a preferred method for low-voltage systems used for portable equipment. In the method, HR grounding and low-resistance grounding resistors are connected to the generator neutral. In the majority of industrial power systems, the winding connection of medium- and low-voltage transformers is Delta primary and Wye secondary, with the neutral brought out. Because the capacitance data on rotating machines and power cables is very approximate, it is highly recommended to measure the system charging current after the installation is complete.
