Study of Transmission Line Protection between Alshugura and Local Market Substations

Abstract

Power system protection basic requirements are Selectivity, Stability, Speed, Sensitivity, Reliability, Economy and Adequateness. Protect transmission line with distance protection scheme sometimes suffers from overreach detection, when fault happens beyond the steady state reach setting. Research studied distance protection scheme, then determined the cause of its overreach problem, and found that problem related with short transmission lines which have a value of system impedance ratio (SIR) more than 4. Transmission line between Alshugura and Local Market substations is 5.3Km long (Sudanese National Grid) was taken as case study. Research made a solution to problem of distance protection over reach in short transmission line by applied line differential protection scheme.