Study On Application Of Programmable Scheme Logic In Microprocessor-Based Protection

In order to improve flexibility of microprocessor-based protection and help manufacturer or user to configure protection logic according to local relay protection type. The programmable scheme logic idea was applied to realize protection logic of microprocessor-based protection in this thesis.At first, design and realization of programmable scheme logic software platform developed were primarily introduced. The software platform provides user with a friendly man-machine interface with basic operation performance. After all kinds of protection types were studied and classified, the modularity idea was applied to encapsulated functionality of every module, then constitute module library. Therefore, user can configure protection logic graph on the software platform to realize protection, according to actual relay protection schematic diagram. Besides, the graph theory was applied to realize traversal and preservation of logic graph on the platform and form programmable scheme logic file.Secondly, based on serial communication principle, a serial communication component was developed. IEC60870-5-101 protocol was also chosen to carry out serial communication between programmable scheme logic software platform and microprocessor-based protection devices. Then programmable scheme logic file was transmitted to protection device through this way.Finally, in order to realize functionality of protection logic, it is necessary to make up a program to analyze its logical relation and build up link between protection program and the file, after programmable scheme logic file has been transmitted to protection device. In addition, a three-step direction current protection single phase schematic diagram was used to verify application of programmable scheme logic in microprocessor-based protection. In conclusion, it proves to be feasible and flexible.