摘要
输电线路安装避雷器是有效的防雷措施,但是有必要合理分析杆塔接地装置冲击特性对避雷器性能的影响。利用EMTP软件搭建220 kV输电线路模型,考虑杆塔接地装置的冲击特性,分析线路安装避雷器的防护效果,计算避雷器吸收的能量,预测避雷器的运行寿命,讨论土壤电阻率对线路避雷器运行寿命的影响。研究结果表明:考虑接地装置冲击特性后,避雷器残压和波形持续时间均小于未考虑冲击特性情况;线路安装避雷器后反击耐雷水平得到大幅提升,50Ω·m土壤电阻率情况下提升幅度可达70%;考虑接地装置冲击特性后反击耐雷水平高于未考虑冲击特性情况,但两种情况下耐雷水平均随着土壤电阻率的增加而降低;考虑接地装置冲击特性后,避雷器吸收能量小于未考虑冲击特性情况,因此避雷器预期寿命高于未考虑情况,在2 000Ω·m土壤电阻率情况下,避雷器预期寿命仍可延长35%。避雷器预期寿命随着土壤电阻率的增大而显著减小,土壤电阻率从50Ω·m增大至2 000Ω·m时,考虑接地装置冲击特性后避雷器预期寿命也缩短了45. 6%。高土壤电阻率地区需要尽可能降低接地装置电阻以提升避雷器防护效果和运行寿命。
Installing line arresters is an effective measure for lightning protection,but it is necessary to analyze performance impact of impulse characteristics of grounding system on transmission line arresters.Equivalent model of 220 kV transmission line were established in EMTP which takes impulse characteristics of grounding system into consideration. Lightning protection level due to back flashover as well as energy absorbed by the line arrester was calculated. Finally,the excepted life of line arrester was estimated and effect of soil resistivity was discussed. Results show that: magnitude and duration of the overvoltage across the line arrester considering impulse characteristics of grounding system is shorter than those without consideration. Installing line arresters could improve lightning protection level which could be increased by 70% in the case of 50 Ω·m,while lightning protection level decreases with the increasing of soil resistivity. Energy absorbed by the line arrester considering impulse characteristics of grounding system is less than that without consideration which results in an increase in excepted life of the line arrester. After considering impulse characteristics of grounding system,excepted life of the line arrester can be prolonged by 35% even in high soil resistivity region. The excepted life of line arrester decreases with the rise of soil resistivity. After the soil resistivity increased from 50 Ω·m to 2 000 Ω·m,excepted life of the line arrester went sharply down by 45. 6%,so it is essential to reduce grounding resistance as low as possible in high soil resistivity region to improve the protection effect and operating life of the arrester.
作者
李文君
杨巍巍
李传荣
LI Wenjun;YANG Weiwei;LI Chuanrong(Southwest University,Chongqing 400715,China;State Grid Technology College,Jinan 250002,China;Shandong Taikai Power Engineering Co.,Ltd.,Tai'an 271000,China)
出处
《电瓷避雷器》
CAS
北大核心
2019年第1期189-194,共6页
Insulators and Surge Arresters
关键词
输电线路
避雷器
接地装置
冲击特性
性能影响
预期寿命
transmission line
line arrester
grounding system
impulse characteristics
performance impact
expected life
