高海拔直流外绝缘试验研究

Experiment Research of DC External Insulation in High Attitude Area

高海拔直流外绝缘问题一直是制约高海拔地区超特高压直流输电工程设计的技术难题。为此,依托昆明特高压实验室在实际高海拔条件下,对特高压直流输电工程外绝缘特性进行了系统研究。研究了±800 k V全尺寸悬式和支柱绝缘子直流污闪特性,以及典型电极和±800 k V直流线路塔头空气间隙放电特性。结果表明,在高海拔条件下,随着线路悬式复合绝缘子和换流站支柱绝缘子串长的增加,其50%污秽耐受电压均成线性增加关系;随着典型长空气间隙和±800 k V直流线路塔头间隙距离的增大,其50%雷电冲击和直流放电电压均成线性增加。该研究成果已应用于高海拔特高压直流输电工程外绝缘的设计和复合绝缘子产品的开发,并取得了良好的社会和经济效益。

The high altitude DC insulation is a technical problem which restricts the design of EHV/UHV DC transmission project in high altitude area. On the basis of ultra-high voltage laboratory in Kunming, we studied the outer insulation properties of UHVDC transmission project in practice high altitude. Moreover, we investigated the DC pollution flashover characteristics of the ±800 k V full size suspension and post insulators, the discharge characteristics of air gap discharge in a typical electrode and ±800 k V DC line tower. The results show that, under the conditions of high altitude, with the increase of DC suspension and post insulator string length, their 50% contamination tolerance voltage linearly increases; and with the increase of the gap distance between the typical long air gap and the ±800 k V DC transmission line, their 50% lightning impulse and DC discharge voltage linearly increase. These research results have been applied to the design of high altitude extra high voltage DC transmission engineering and the development of the composite insulator products, and have achieved good social and economic benefits.