A fast adaptive protection scheme for distributed generation connected networks with necessary relay coordination

Protection of a distribution network with connected distributed generators (DGs) is quite challenging due to the change in DG connection. Thus the relay settings have to be updated, every time there is a change in network configuration. In this paper, identification of faulted section and fast isolation of same has been addressed with suitable relay coordination. In conventional methods coordination of OC relays is obtained through careful time grading. In such schemes faults close to the source have a larger clearance time, which might cause trouble in longer lines. Here a communication based relay coordination scheme is proposed to keep the fault clearance time independent of fault location. The proposals have been verified on test systems available in the literature, through MATLAB/Simulink simulations and results are compared. Also a convenient and reliable back up protection scheme has been proposed.