Comparison of results of optimization by searching of equivalent system

The paper presents problems concern transmission systems identification during non-simultaneous faults in electrical power system. Investigation is connected with the parameter identification of reduced equivalent systems representing complex electrical power systems. The method-parameter identification criterion was chosen, for equivalent systems determined to modification. It was assumed at the beginning of investigation, simply equivalent system consisted from resistance and reactance and then extended on more complex structures. The modification of least-square method proposed in this work was tested for signals with high level of high frequency free components with MicroTran program and for signals with low level of this components with NETOMAC program. There were also used the quasi-Newton and gradient less Powell methods. There are presented the analysis of search of optimum transmission line representation for transients investigations during non-simultaneous faults.