Novel alpha-transform distance relaying scheme

This paper presents a simple novel distance relaying scheme based on the 3-D alpha (α)-hyperplane of (V_α- I_α- P_α) representing the relay location measurement at the bus. The nonlinearly transformed voltage, current and apparent power carries information about the fault location and fault condition as bolted or high impedance faults (HIF). The paper describes the tripping mechanism and fault detection conditions in the α-hyperplane for transmission line distance relaying. The scheme is both simple and novel and takes into consideration the quasi dynamic nature of the faults, fault impedance nonlinearity and transmission line capacitance backfeed and resonant oscillations causing amplitude modulation of transmission line segment phase currents. The relay can be easily implemented using analog/digital or hybrid hardware. The relay is based on a transient model and includes all asymmetry and nonlinearity associated with different fault types, fault location, preloading and voltage power angles. The detection is based on transformed α-variables (V, I, P)