Active power differential algorithm for protection of transmission lines

A differential algorithm for phase selective detection of high impedance single-phase-to-ground faults (HIF) on high voltage lines is presented. It is based on the recognition of the fundamental frequency active power consumption of a resistive fault. In order to maximize the sensitivity of the system, a method for the approximation of the measuring system´s actual uncertainties is proposed. Thus, adaptive tripping thresholds are realized. The algorithm presented relies on the superposition theorem (delta-principle).