A New Fault Location Algorithm for Use with Current Differential Protective Relays of Two-Terminal Line

A new fault location algorithm utilising synchronised measurements of two-end currents and one-end voltage is presented. It has been assumed that such fault location algorithm is incorporated into the current differential relay. In this way, the communication between the line ends of differential relays is utilised. By incorporating the fault location function, an increase of the relay functionality is achieved. The derived fault location formula is compact and covers different fault types – what requires setting the appropriate fault type coefficients. High accuracy of fault location is assured by strict considering of the distributed parameter line model. The solution is obtained with applying iterative calculations based on the Newton- Raphson method. For starting the calculations, the solutions obtained for the lumped line model are utilised. The performed ATP-EMTP evaluation prove the validity of the presented fault location algorithm and its high accuracy