Power system fault analysis based on intelligent techniques and intelligent electronic device data

摘要

This dissertation has focused on automated power system fault analysis. Newcontributions to fault section estimation, protection system performance evaluationand power system/protection system interactive simulation have been achieved. Intelligent techniques including expert systems, fuzzy logic and Petri-nets, as well asdata from remote terminal units (RTUs) of supervisory control and data acquisition(SCADA) systems, and digital protective relays have been explored and utilized tofufill the objectives.The task of fault section estimation is difficult when multiple faults, failuresof protection devices, and false data are involved. A Fuzzy Reasoning Petri-netsapproach has been proposed to tackle the complexities. In this approach, the fuzzyreasoning starting from protection system status data and ending with estimation offaulted power system section is formulated by Petri-nets. The reasoning process isimplemented by matrix operations. Data from RTUs of SCADA systems and digitalprotective relays are used as inputs. Experiential tests have shown that the proposedapproach is able to perform accurate fault section estimation under complex scenarios.The evaluation of protection system performance involves issues of data acquisition, prediction of expected operations, identification of unexpected operations anddiagnosis of the reasons for unexpected operations. An automated protection system performance evaluation application has been developed to accomplish all the tasks. The application automatically retrieves relay files, processes relay file data,and performs rule-based analysis. Forward chaining reasoning is used for predictionof expected protection operation while backward chaining reasoning is used for diagnosis of unexpected protection operations. Lab tests have shown that the developedapplication has successfully performed relay performance analysis.The challenge of power system/protection system interactive simulation lies inmodeling of sophisticated protection systems and interfacing the protection systemmodel and power system network model seamlessly. An approach which utilizes the"compiled foreign model" mechanism of ATP MODELS language is proposed to modelmultifunctional digital protective relays in C++ language and seamlessly interfacethem to the power system network model. The developed simulation environmenthas been successfully used for the studies of fault section estimation and protectionsystem performance evaluation.