Novel adaptive algorithm for optimal relay setting with improved coordination

With the penetration of distributed generation (DGs) at distribution level, protection of a distribution network is quite challenging due to the change in operating mode and system topology. Thus the relay settings have to be updated every time there is a change in network configuration. This paper presents a novel adaptive algorithm with fastest backup protection in which new optimal relay settings (pickup current and time dial setting) calculated by proposed algorithm solves the problem regarding changing of coordination time interval and critical clearing time as mode changed. This proposed algorithm uses the numerical inverse overcurrent relays which have the capability of memory storage and to cope up with communication. The proposed algorithm has been verified on test systems of different operating modes using MATLAB/Simulink and C program. Results showed the importance and necessity of this scheme in maintaining the optimal performance of the relays under changing operating modes.