±535kV直流断路器用隔离供能变压器电场计算与起晕校核

Electric Field Calculation and Corona Check of Isolated Power Supply Transformer for ±535 kV DC Circuit Breaker

直流断路器用隔离供能变压器作为新型电力系统中的关键设备,需要保证其正常工作时表面电场强度在电磁环境规定的限值之内。为了得到准确的计算结果,讨论了瞬态电场、静电场与恒定电场的区别,通过绝缘材料伞裙结构分析了空气电导率对恒定电场的影响,提出了交直流混合复杂设备的电场校核原则,完成了供能变压器的电场仿真分析与起晕校核。结果表明,在对该供能变压器进行电场计算时,为了留有裕度,应当采用静电场进行导体金具的起晕电场校核;采用恒定电场进行绝缘材料的绝缘性能设计,同时还要考虑空气电导率的影响,选择空气电导率10-16 S/m(干燥)和10-12 S/m(湿润)中的计算结果最大值作为参考最大电场。

As the key equipment in the new power system, the isolated power supply transformer for DC circuit breaker needs to ensure that its surface electric field strength is within the limits of electromagnetic environment. In order to get accurate calculation results, the differences among transient electric field, electrostatic field and constant electric field are discussed, the influence of air conductivity on constant electric field through the structure of insulating material umbrella skirt is analyzed, and the principle of electric field check for AC/DC hybrid complex equipment is proposed. The electric field simulation analysis and corona check of the power supply transformer are completed. The results show that when calculating the electric field of the power supply transformer, in order to keep a margin, it is suggested to use electrostatic field to check corona inception field of conductor fittings. Constant electric field is used to design the insulation performance of insulating materials. At the same time, the influence of air conductivity should be considered, and the maximum value of the calculation result under air conductivity of 10-16 S/m(dry) and 10-12 S/m(wet) should be selected as the reference maximum electric field.