摘要
有载分接开关是高压直流输电系统中换流变压器重要的部件,维持系统运行中阀侧直流电压恒定不变,补偿电压波动;实现直流输电系统降压运行。在直流系统换相过程中会有较大的短路电流变化率(di/dt),增加了分接开关的切换负荷。分接开关的调压范围大、操作频繁,极性选择器动作产生特征气体。针对换流变压器用有载分接开关运行时的要求及现象,研制了±800k V直流换流变压器用真空式有载分接开关样机,由切换开关、带有极性选择器的分接选择器和电动机构组成。提出了切换开关双真空触头双电阻过渡原理,即串联双断口真空切换,主通断触头和过渡触头功能轮换,切换程序对称,过渡电路中4个真空触头切换任务一致。研制了更高绝缘等级的E级分接选择器。设计了真空化极性选择器,更有效地抑制极性选择器动作时产气。该分接开关具有灭弧能力强、过渡触头断口间的恢复电压低、切换开关油室温升低、整台分接开关电气寿命高等优点。该分接开关样机已顺利通过了型式试验的考核。
The on-load tap-changer(OLTC) is an important part of converter transformer in high voltage direct current(HVDC) transmission system, which maintains the constant DC voltage of valve side in the system operation and compensates the voltage fluctuation. In the commutation process of DC system, there will be a large short circuit current change rate(di/dt) to increase the switching load. The tap-changer has large regulation range, frequent operation and characteristic gas generation during reversing change-over selector operation. In view of requirements and phenomenon of the OLTC of the converter transformer, the vacuum type OLTC of ±800k V DC convertor transformers was developed, which was composed of the diverter switch, the tap selector with reversing change-over selector and motor drive mechanism. This paper presents double vacuum contacts and double resistance transition principles for diverter switch, that is, the series double fracture vacuum switch, the alternating function of main switch contacts and transition contacts, switch procedure symmetry and breaking duty of four vacuum contacts in agreement in the transition circuit. An E insulation tap selector was developed. The vacuum reversing change-over selector was designed to effectively suppress the gas generation. This OLTC has the advantages of strong arc extinguishing ability, low recovery voltage between transition contacts, low temperature rise of the switch compartment, high electrical life of the whole OLTC. This OLTC has successfully passed the type test.
出处
《中国电机工程学报》
EI
CSCD
北大核心
2016年第19期5350-5356,5417,共8页
Proceedings of the CSEE
