Transmission line models for line protection

Methods for the protection of power transmission lines can be based on various line models ranging from a 50 Hz impedance, an L-R series circuit, and a π-equivalent to distributed parameter models. The application of such line models for deriving distance protection schemes is discussed. Fundamental concepts are introduced which allow various protection schemes to be discussed in a unified and novel framework. A large class of algorithms are then examined with regard to their ability to identify the location of a fault on a transmission line in the presence of transient phenomena which distort the sinusoidal voltage and current waveforms shortly after the occurrence of the fault.