火电机组发变组离相母线系统绝缘研究与应用

Research and Application on Insulation of Generator-transformer Isolated Phase Busbar System for Thermal Power Unit

火电机组发变组绝缘是机组冷备用转热备用时重要的一项电气绝缘性能指标。在日常运行维护过程中,机组停运时发变组绝缘并不能长期自我保持合格。对发变组绝缘低产生的薄弱环节展开逐项治理,增加吹扫管路将主变、高厂变20 kV侧升高座纳入到离相封母系统内,主动打破、重构其密封结构,将离相封母系统改造为半开放式系统,引导离相封母空气向外、定向流通,使发变组绝缘长时间冷态下可保持在100 MΩ以上。相较DMC等绝缘材料升级,其投资少、易实现,且系统免维护。

The insulation of generator-transformer unit in thermal power unit is an important electrical insulation performance index when the cold standby unit is switched to the hot standby unit. In the daily operation and maintenance process, the insulation of generator-transformer unit can not keep up with itself for a long time when the unit is shut down. The weak links caused by the low insulation of the generator-transformer unit are dealt with one by one, and the 20 kV side risers of the main transformer and the high power plant transformer are brought into the isolated phase sealing bus system by adding the blowing pipe, and the sealing structure is broken down and reconstructed on the initiative. The separated phase sealing bus system is reformed into a semi-open system, which leads the separated phase sealing bus air to flow outwards and directionally, so that the insulation of generator-transformer group can be kept above 100 MΩ for a long time. Compared with DMC and other insulation material upgrade, it is less investment, easy to realize with free maintenance.