IMPROVEMENT IN THE TRANSIENT CURRENT DIFFERENTIAL PROTECTION BASED ON CORRELATION ANALYSIS

The principle of the current correlation differential protection based on the correlation integration was analyzed further in this paper. Through the analysis, we found that this criterion has disadvantages in some system conditions. Aiming to the applied requirement in the field, an improved applied correlation criterion was proposed. The power system models of different structures using ATP were built to simulate the improved criterion completely. Simulation studies show that the improved criterion preserves the advantages of correlation criterion, which is simple, fast and not effected by the distributed capacitance, more sensitive and reliable, easy to set. Pilot studies prove that the improved criterion is very suitable for the protection of EHV/UHV transmission lines