750kV变压器长时感应耐压试验标准探讨

Discussions on Long Duration Inducted Voltage Test Standard for 750 kV Transformers

750 kV官亭—兰州东示范工程投运5年来,西北750 kV电网建设突飞猛进,但作为主设备的变压器频繁出现绝缘事故,对于多年前制定的750 kV变压器技术规范、标准有必要进行反思。长时感应耐压试验标准是750 kV变压器绝缘设计和考核的重要依据,通过750 kV变压器技术规范、试验标准与1 000 kV变压器技术规范、试验标准进行比对,结合现场变压器绝缘击穿案例,通过计算和分析,提出了750 kV变压器长时感应耐压试验标准的改进方案。

The northwest region has witnessed a rapid development in the 750 kV power grid construction since the 750 kV Guanting-Lanzhoudong Transmission Demonstration Project was put into operation five year ago. However, as several faults on the insulation of the 750 kV grid transformer, the most important piece of equipment in the 750 kV grid, have been observed in recent five years, it is necessary to re-evaluate the technical specifications and standards for the transformer as stipulated then. The long-time inducted voltage test standard is one of the key bases, on which the insulation design and evaluation of the 750 kV transformer were conducted. By comparing the technical specifications and testing standards of the 750 kV transformer with those of the 1 000 kV transformer, together with the on-site analysis of the 750 kV transformer breakdown, the paper proposes a proposal for updating the long-time induced voltage test standard for the 750 kV transfornler.