A Study Of A Protection Device Based On Microprocessor For High-Voltage Transmission Line

HV transmission lines are the most important electric components in electric power system, so the performance of line protection has great influence on the security and stability of power system. In recent years, with the HV electric networks developing and the degree of automation of electric networks improving, the higher and newer performance of protective relaying for HV transmission lines are requested. At the same time, with the progresses of computer, especially with the applications of DSP, the hardware resource of microprocessor protection get richer and the computing speed turn faster, which provides the powerful support for the improvement of the microprocessor protection functions. It is of great theoretical and practical significance to develop more advanced microprocessor based protective relaying set for HV transmission line based on the new theory of line protection. At first this thesis introduced the history and new directions of microprocessor based protective relaying for transmission lines. Then the project design of protection is put forward according to the needs of HV transmission line. In this thesis, The design principles , the function settings , the hardware structure and the plug-ins design characteristic of the protection device are introduced. Principle of relay protection is the heart of the performance of protective relaying. In this thesis, the research of protection principle is used for reference, such as a sequence directional element based on compensating voltage, a high sensitive starting element based on three phase simultaneity sampling values, a novel fault phase selector. This thesis sets forth the basic theory. The software design is important work during the research of the device. Compared to conventional software design based on flow chart, the protection software is developed based on relay function module, which leads to the separation of time sequence and logic. The modular structure makes the development and maintenance software more convenient. And the records of relay function module are favorable to the debugging of protection software and the analyzing of fault. This thesis introduced the software design based on relay function module and its realization. In order to provide convenience to users, the protective relaying device provides management system, the function of which is management of running and debugging, monitoring of parameters on line and communication, etc. This thesis expounds the function character of management system, the structure of software and realization. After the design of protective relaying device for HV line, the static simulation experiments for the HV transmission line protection system is applied. The main content and the results of the experiments are introduced in this thesis. Finally, the thesis gives the systematical summarize and points out the further work.