Performance of the Neutralizing Transformer from a Volt-Time Area Approach

A fault to ground on a power transmission facility serving a power station can produce a rise in potential of the power station ground with respect to remote earth, which is due to fault current returning to the power system neutral through the earth and station grounding structure. The magnitude of the ground potential rise ( GPR) is a function of the transient characteristics of the power system during a fault, together with available fault current and power station ground resistance with respect to reference ground. Ground potential rise may range fromii negligible voltage to many thousands of volts. The GPR waveforn consists of a 60-Hz steady-state component and, depending upon the phase angle of the transmission line voltage at fault initiation, may be accompanied by an asymmetrical, exponentially decaying component.