Influence of new over - head power lines construction on the operation of the relay protection system

One of the basic ways to improve the safety of either a part or the whole of the power system (PS) is construction of new overhead power lines. Since such interventions in the system are rare nowadays for economic, as well as ecological reasons, every significant alteration requires detailed analyses of the influence of line construction on the entire power system. In this paper the influence of the construction of new lines on the relay protection system has been described. Power system has been modeled by using the CAPE software and relay protection operation has been analysed. The first part of this paper describes the power system before reconstruction. Accuracy of the software model has been tested by comparison with the real faults in the network recorded by numerical relays. Distribution of fault current in the current and new system configuration has been shown by analysing the single-phase high-resistance fault, and functionality of the relay protection in both instances has been analysed.