Relay Setting Value Verification And System Development In Power Systems

Traditional relay values are set in the high-current circumstance, verified in thesmall-current circumstance, and would remain unchanged in normal operation. However,when the power system operation model changed, the relay values probably can’t meet theneeds of sensitivity and selectivity. So it is particularly important to verify the relay settingvalues in real time to ensure the security of power system.To solve the realistic problem, this paper builds an expert system of regional power gridrelay setting value verification. The system reads power grid model and topology informationfrom the energy management system, reads operation information from the supervisorycontrol and data acquisition system, uses all the information building the expert system’s factbase; obtains the rules of relay setting value verification to build the expert system’s rule base;researches the methods of fault calculation to achieve the relay setting value verificationreasoning mechanism; Besides, builds a friendly interactive interface by the principle ofuser-oriented.In the process of building knowledge base, document object model method and ADO.netmethod are used to solve data reading problem. In the process of fault calculating, phasecomponent method is used to solve the problem of power system parameter symmetry. In theprocess of achieving relay setting values verify reasoning mechanism, Ward equivalentmethod and parallel computing method are used to solve the computing efficiency problem.In the functional layer, the system mainly designed data management module, faultcalculation module, and relay setting value verification module. All these modules aredescribed respectively in chapter three, four, and five. Besides, the data management modulecorrespond the knowledge base building of expert system, the relay setting values verifymodule correspond the reasoning mechanism building of expert system.The system software adopts Browser/Server (B/S) structure, uses Visual Studio.net asplatform, uses C#language developed a web service, so users can access the web servicethrough an internet browser in order to verify relay setting value.