Genetic Algorithms For Fault Diagnosis Of Electrical Power System

This thesis is dealing with fault section estimation and fault location in power systems by using the Refined Genetic Algorithms.Usually, fault section and fault type are estimated by using the information from protection relay and circuit breaker. Fault section estimation and fault type identification are called fault diagnosis, which can be resolved by 0-1 plan method using logic relationship among the circuit breaker, protection relay and faulted unit.Genetic algorithm (GA) is an optimal algorithm with the iteration that simulates the process of biologic evolution. All resolutions are arranged in the order of their object values in every iteration. Some of them are selected in the arranged order and they are operated by the genetic operator, such as crossover and mutation, so that a new generation of resolution is produced. Repeat this process until to some target to be needed. There exist the problem of "early mature" in SGA. Object values of some resolutions are very larger than the others' and the resolutions are dominant to obtain much choice of production. These resolution are full of all space of resolution after a few generations and then the process of iteration is finished, or say that it is convergent, but it converge to local optimum.A new method based upon Refined Genetic Algorithm (RGA), which global optimum is easily converged with, for the fault section estimation problem is presented. There are some new operators in RGA and basic operations of RGA are different from those of SGA. The probability of crossover operator Pc and the probability of mutation operator Pm in SGA are invariant but they in RGA are variable. Method based RGA is a good candidate for fault section estimation. The simulation results have shown that the RGA method can find multiple optimal solutions efficiently in a single run.Along with the development of power systems, the electric transmission lines have higher and higher voltage grade and transfer capacity. It's very necessary to find an effective method of locating fault location. The recent study indicated that RGA has certain advantages in fault location of power systems. The application of RGA in this field is described by a single-phase ground fault of a simple system. The result indicated that RGA could quickly and accurately locates the fault position and identifies fault types in the power systems.