A Decoupled Adaptive Overcurrent Coordination Considering N-1 Contingency and Distributed Generation Using an Effective Evonorm Algorithm

The offline protection coordination problem in the interconnected network has always been one of the important tasks for the researchers. This problem is remarkably constrained and non-linear when considering both the time dial and pickup settings. In addition, the consistent load and topology changes as well as the stochastic renewable distributed generation (DG) made the fixed protection settings become more vulnerable to coordination loss when a fault occurs. Hence, this proposal consists of an adaptive protection scheme that adjust the pickup current and time dial relay settings in a decoupled manner. Where the pickup current settings for each DOCR are determined by the maximum N-1 contingency current that passes through the relay. In addition, the DOCRs time dial settings are optimized alone using the EVOlutionary Algorithm of Random Variables with NORMal Distributions (Evonorm) algorithm. The proposed Evonorm algorithm which is an easy and effective method along with the seeding technique become suitable for adaptive protection coordination strategy. The proposal has been tested on the modified IEEE 14 and 30 bus systems. And results have shown that coordination is achieved.