特高压交流试验示范工程主变保护配置探讨

Configuration of Transformer Protection in UHV AC Pilot Project

主变保护的配置及整定对保证主设备的安全至关重要,特高压交流试验示范工程的主变压器由主体变压器和调压补偿变压器两部分组成,采用中性点无励磁调压方式,且特高压系统具有自身独有的特性,因此特高压主变的保护有其特殊性,而目前尚无标准及整定规程可依。针对此情况介绍了1000kV特高压交流试验示范工程主变保护配置情况和独立设置调压补偿变保护以提高调压补偿变小故障情况下灵敏度的必要性。根据系统调试期间录波数据,以及主体变和调压补偿变励磁涌流的特点,综合考虑调压补偿变差动保护的可靠性和安全性,建议调压补偿变差动保护励磁涌流闭锁原理采用"三取二"或循环闭锁的闭锁方式。分析表明,目前的保护配置完善可靠,经实际检验,可以满足特高压主变压器安全稳定运行的需求。

The configuration and setting of transformer protection is very imPortant to ensure the safety of power equipment. The UHV AC pilot project transformer is composed of two parts： the main transformer, the regulation and compensating transformer. The protection of transformer has its particularity because the UHV system has its special feature and the regulation of transformer is from neutral terminal on UHV autotransformers, not from the intermediate voltage line terminal. This paper introduces the system connection and transformer protection configuration of 1000 kV AC pilot project. There are individual differential protections for the regulation transformer and the compensating transformer in order to enhance the protection sensitivity during the light fault. The inrush current characteristic of main transformer, regulation transformer and compensating transformer is also discussed according to the recorded data during the system debug. Considering reliability and security of differential protection of regulation transformer and compensating transformer, three-take-two or three-take-one braking scheme is suggested. The results show that the present configuration is reliable and can guarantee the safe and stable operation of UHV pilot project.