Analysis of static var compensator-based distance protection of transmission network considering different line lengths: a case study of nigerian grid

This paper presents a Matlab/Simulink-based approach for investigating the performance of Static Var Compensators (SVCs) on distance relay protection installed at varying lengths of the practical Nigerian 132-kV sub-transmission grid system. The shunt-connected SVC is located at the Ikorodu sub-station end of the Ikorodu-Sagamu 132-kV transmission line. The faults are simulated on a short line (18.4 km), medium line (100 km) and long line (226 km) in the Matlab/Simulink model of the Ikorodu-sagamu 132kV sub-transmission distance protection scheme. The results obtained are then used to investigate the impact SVCs have on distance protection relays when they are connected and disconnected for varying transmission line lengths whilst keeping all other parameters constant. The results obtained show that the SVC despite being advantageous, also introduces under-reach and over-reach tendencies for different zone faults (zones 1 and 2) as simulated on varying lengths of 132-kV transmission lines. This implies that a further simulation is required to recommend measures aimed at reducing the error margin introduced by the SVCs.