Field based case studies on overcurrent relay coordination optimization using GA-NLP approach

To reduce the damages due to the faults, protective system must have fast response. Fast isolation of faults necessitates minimum operating time of Over Current (OC) relays. Operating time of OC relays can be optimized by formulating the coordination problem as a Linear Programming Problem (LPP). Non Linear Programming Problem (NLP) of coordination can also be formed in which Time Multiplier Setting (TMS) and Plug Setting (PS) both are considered for optimization. This paper presents Linear and Non Linear Programming techniques to solve the OC relay coordination problem for a realistic power system in India. The problem is solved using Genetic Algorithm (GA) and presents comparative analysis of LP and NLP techniques.