Power System Protection and Coordination In the Presence of Distributed Generators

In this book, adaptive protection schemes for power systems with DG units are proposed by integrating fault diagnosis with protection relay coordination strategies. An automated fault diagnosis method is developed using three staged radial basis function neural network (RBFNN) in which the first RBFNN determines the fault distance from each source, the second RBFNN identifies the exact faulty line and the third RBFNN determines the circuit breakers that must be open or close for isolating the faulty zone. After identifying the exact faulty line, then protection relay coordination is implemented. A new protection coordination strategy using the backtracking algorithm is proposed in which it considers the main protection algorithm to coordinate the open/close states of relays so as to isolate the faulty line. Then a backup protection algorithm is considered to complete the protection coordination scheme for isolating the malfunction relays of the main protection system. The fault diagnosis based on RBFNN and protection coordination using the backtracking algorithm were developed in MATLAB and the fault simulations on the test systems were carried out using the DIgSILENT software.