In response to the main transformer trip accident caused by a voltage transformer fault on the generator outlet of a certain power plant,a comprehensive review of the history and present recorded data,combined with the protection trip message and on-site equipment inspection information,it was conducted that the accident was caused by the grounding of the secondary side of phase c of the generator outlet voltage transformer,which led to the grounding of the primary side of phase a and phase b of the voltage transformer,and ultimately developed into a two-phase grounding short circuit fault,and the correctness of the analysis and judgment was verified through theoretical derivation and calculation.During a comprehensive inspection of the main equipment parameters,it was discovered that the insulation parameters of the voltage transformer did not meet the requirement of standards.Finally,an accident handling plan was proposed,replacing imported equipment with domestic voltage transformers.After rectification,the power frequency withstand voltage level of the voltage transformers was improved,and the reliability and safety of unit operation were increased.
关键词
电压互感器/两相接地短路/故障录波/波形图/工频耐受电压
Key words
voltage transformer/phase-phase earth fault/fault record/waveform/power frequency withstand voltage level
维普
万方数据