特高压交流输变电装备最新技术发展

Achievements in the Newest Technology of UHV AC Power Transmission Equipment

特高压工程大规模建设,核心装备是关键。为促进特高压交流输电技术的进一步发展,对特高压交流变压器、气体绝缘金属封闭开关设备(GIS)、串联补偿装置和避雷器等关键装备的最新技术发展进行了总结和展望。结果表明:特高压变压器应选择局部放电概率为1‰时的电场强度允许值作为许用场强;采用器身端部磁屏蔽、油箱电屏蔽、油箱磁屏蔽、采用不导磁钢板等漏磁控制措施可有效降低1 500 MVA大容量特高压变压器的漏磁和温升;特高压断路器的开断能力可达63 k A,采用基于"三回路法"的合成试验回路可突破试验设备限制,完成1 100 k V断路器开断试验;明确了通过在"立式"隔离开关静触头侧安装阻尼电阻来限制VFTO的幅值和频率;提出了从持续运行电压的角度出发,特高压避雷器的额定电压降低到780 k V是安全的。未来特高压交流输变电装备应在高可靠性、大容量、新工作原理和性能参数优化等方面进行深入研究。

The core devices are key factors for large-scale construction of UHV projects. In order to facilitate the further development of ultra-high-voltage（UHV） alternating current（AC） transmission technology, we summarized the new technological developments of China＇s UHV AC power transmission equipment including transformer, gas-insulated high-voltage switchgear, series compensation device and arrester in recent years. The obtained results show that the allowable value of electric field relevant to partial discharge（PD） possibility of 1 per thousand should be adopted. In addition, the control methods of leakage magnetic field consisting of terminal magnetic shielding, electric shielding of oil tank, magnetic shielding of oil tank and the use of steel plate free of magnetic can effectively depress the leakage magnetic field and temperature rise of 1 500 MVA large-capacity UHV transformer. Furthermore, the breaking capability of UHV circuit breaker is confirmed as 63 k A. The comprehensive test circuit based on ＂three-loop method＂ can make a breakthrough on the limitation of test equipment, which is successfully employed for the breaking test of 1 100 k V circuit breaker. The damping resistance is installed on the fixed contact of vertical isolating switch to reduce the magnitude and frequency of VFTO. Finally, it is proposed that the rated voltage of UHV arrester should be safely reduced to 780 k V according to the continuous operation voltage. Future research of UHV AC power transmission equipment should be focused on such aspects as high reliability, high capacity, new principles, and performance parameters optimization.