Study On Wide Area Protection Regional Fault Diagnosis

Improving the reliability of relay protection, as an important guarantee of power system, has been concerned about development of the system. With expansion of power net interconnection and increasingly complexity of run mod, it's more difficult of protection coordination and setting, coupled with economic considerations often required power grid to run on the limit state, the influence of protection incorrect actions is more serious. At the same time, network communication and digital computing technology have matured for the protection improvement. Wide area protection, build on these modern technology, is more and more concerned home and abroad.One of the main research fields of wide area protection system is to use the wide area information simplifying the protection coordination and setting, promoting the protection reliability. How to improve the structure zone division, protection principle, fault-tolerant and reliability of wide area protection system is proposed in this article, increasing the adaptability for large power net.First, the concept of wide area protection system and its present research are introduced, analysis of some exist key points of the system research. Compared of several types of common structural features of wide area protection system, a hierarchical regional structure was selected, and the regional division of the system structure was introduced, including the basic principles of division and the algorithm process, an example is used to verify the effect of the process.The characteristics of active power differential algorithm is also analyzed, by simplifying the criteria makes the principle with high sensitivity of high impedance ground fault, and coordinated with the current differential criterion constitutes a simple and prefect wide area differential protection principle. By divided wide area protection principle into two categories, graph algorithm was build for regional division and different principle conclusions. The algorithm processes at different station levels, such as terminus, regional centers and general sub-station, and the comparative analysis of different graph algorithms in the application are introduced. The program was verified according to an typical sub-station system.Finally, by the analysis of fault-tolerant of the wide area protection system and introducing the reliability analysis of relay protection the traditional theory, the reliability analysis of the wide area protection system was discussed. Analyzing the running states with communication and algorithm failure, the reliability approach of wide area protection system using Markov State Space Method was proposed.