1 100 kV特高压交流复合套管局放原因分析及改进措施

Partial Discharge Cause Analysis of 1 100 kV Extra-High Voltage AC Composite Bushing and Improvement Measure

1 100 kV特高压交流复合套管在例行出厂试验中出现局放超标问题,从耐压设备、试验场地、装配过程、测量系统、元件质量等多个方面进行原因分析,完成套管局放定位,后借助有限元方法对该位置予以确认。综合各种因素分析,局放产生的原因是由于空心复合绝缘子制造工艺的分散性,导致绝缘件内部出现缺陷,进而诱发局部放电。根据有限元分析结果,提出了双层屏蔽结构优化措施,重新制造样机并进行试验,试验结果表明:优化后的屏蔽结构,能有效提高套管的起晕电压,降低局放水平,保证产品可靠安全运行。

The partial discharge （PD） problem occurs in the 1 100 kV extra-high voltage AC composite bushing＇s routine factory test. This paper carried out the cause analysis from the respects, such as voltage test apparatus, test site environment, assembly process, test system, and component quality etc to complete the bushing PD location and to determine the location by the finite element analysis method. Accord-ing to the synthesized analysis of various factors, it was found that the reason for PD was dispersion on composite bushing7s manufacturing process, which led to internal defects in insulators and caused PD to happen ultimately. Based on the finite element analysis result, this paper proposed the double-deck shield structure optimization measures to re-manufacture the prototype, carrying out test for it. The final test result shows that the optimized shield structure can raise bushing’s discharge inception voltage effectively, which reduces the PD level to ensure the reliable and safe operation for the products.