±800 kV特高压直流输电用6英寸大功率晶闸管换流阀

6 Inch High Power Thyristor Valves for ±800 kV UHVDC Transmission

现如今,中国有多条±800 kV特高压直流输电项目正在建设或正在规划之中。较高的输电电压及其较高的稳态、瞬态过压而产生的晶闸管换流阀绝缘设计难点已在云南—广东±800 kV/5 000 MW直流输电工程中得到了研究和解决,但是在向家坝—上海特高压直流输电±800 kV/6 400 MW工程中,必须采用更大功率的晶闸管,才能满足额定电流4 000 A的要求。为了满足实际工程需要,基于硅片的新一代6英寸大功率晶闸管应运而生,同时,为了满足更高直流电流的要求,在晶闸管换流阀设计中,应用了相关新的设计技术。笔者介绍了向家坝—上海特高压直流输电工程中复龙站晶闸管换流阀设计,包括阀的结构、电气设计、机械设计、阀内部电器件选择等,另外,对6英寸晶闸管的特点作了介绍。复龙站换流阀型式试验已分别在德国西门子、中国西安高压电器研究院有限责任公司完成,试验结果表明,基于6英寸晶闸管的向家坝—上海±800 kV特高压直流输电工程复龙站换流阀设计可靠,可保证向家坝—上海输电工程复龙站换流阀的长期、可靠运行。

Several UHVDC transmission schemes employing ±800 kV DC transmission are presently under construction or in planning in China.The challenges for insulation design resulting from this high transmission voltage and its associated steady state and transient overvoltages have already been investigated and solved during the design work for the Yunnan—Guangdong ±800 kV/5 000 MW transmission project.However,the even higher rated transmission capacity of 6 400 MW defined for the Xiangjiaba—Shanghai ±800 kV transmission scheme additionally required more powerful thyristors with increased current rating of 4 000 A.Consequently,a new generation of high-power thyristors were developed based on silicon wafers with a diameter of 6 inches.In parallel the complementary technology of the thyristor valves was adapted to the higher current rating.This paper provides an overview of the design of the thyristor valves for the Fulong converter station of the Xiangjiaba—Shanghai transmission project including insulation design,current rating and the features of the new 6 inch thyristor.