Analysis of Dynamic Stability and Thermostability of Bus Bar and Disconnect Switch in Excitation System
|School||Harbin Institute of Technology|
|Keywords||bus bar disconnect switch dynamic stability thermostability thermal network method|
Excitation system is an important part of synchronous generator. It plays an important role in increasing working reliability of power system parallel unit. In excitation system, bus bar and disconnect switch are two types of basic devices. In order to maintain the reliability level of synchronous generator, short-circuit test for excitation system need to be done. In this test, short-circuit may flow throw every device. It will cause many negative influences including heating and disconnect force. So a higher request of dynamic stability and thermostability has been put forward. In order to make sure whether they can work reliably under such situation, research on the dynamic stability and thermostability of bus bar and disconnect switch need to be done.Based on the FEM method, the analysis on bus bar and disconnect switch has been done under short-circuit situation. Simulation data of dynamic stability has been calculated. Based on analytic computation method the analysis on them has been done. Comparing the simulation result, the analytic model has been amended so that it can meet the demand of engineering calculation accuracy. The engineering calculation expression for dynamic stability has been inducted.Building the 3-D FEM model, the thermostability of bus bar and disconnect switch has been studied. The temperature distribution and key point temperature has been calculated. Transient temperature rise has been calculated by analytic method. Based on thermal network method, thermal part of disconnect switch has been divided, thermal network has been built, the steady state end point temperature and highest temperature have been calculated. Comparing the FEM simulation results, thermal network model has been amended to meet the demand of engineering calculation accuracy.In this paper, the dynamic stability and thermostability of bus bar and disconnect switch have been analysed. The problem of the analysis of dynamic stability and thermostability for such type devices in excitation system has been solved. The analysis level of bus bar and disconnect switch has been increased. And some research on switching apparatus modeling based on thermal network method has been done. It is of great value to the analysis of excitation system short-circuit test reliability and engineering application.