大型汽轮发电机主绝缘耐压和电老化试验中定子线棒端部防晕技术的研究

大型汽轮发电机在主绝缘耐压和电老化试验中,可能出现定子线棒端部闪络和防晕层过热的情况,从而损伤主绝缘,影响试验顺利进行。本文通过建立真机线棒端部的Pspice仿真模型,模拟了线棒端部绝缘表面电场分布,分析了端部闪络的原因。通过进一步的仿真研究,提出了线棒端部防晕的技术方案,并试制了线棒端部防晕装置。试验结果表明,该防晕装置可有效防止线棒端部闪络和防晕层过热。

Study on Anti-corona Technique at the Ends of Stator Bar in the Tests of Withstand Voltage and Electrical Aging for Large Steam Turbogenerator Stator Winding Insulation

During the tests of withstand voltage and electrical aging for large steam turbo-generator stator winding insulation, the flashover at the ends of stator bar and overheating of the corona- protective coating might take place, which would cause the winding insulation to burn out and the test not to continue . The model for the end of the stator bar has been established in this paper. The electrical field distribution on the surface of insulation at the end of stator bar has been calculated with the aid of Orcad/Pspice software, according to which the cause of the flashover at the end of the stator bar has been analyzed. The technical scheme for anti-corona is presented by the further simulation study, based on which the anti-corona device has been manufactured. It is verified that the device is effective to protect the corona protective coating at the ends of stator bar against flashover and overheating.