特高压换流变用550kV防爆燃间隙油中电弧转移熄弧性能试验研究  

Experimental Research of Oil Arc Transferred and Extinguished by AC 550 kV Triggered Gap for UHV Converter Transformer to Prevent Deflagrate

作　　者：李志兵 李晓昂[2] 张然 徐晓东 郑占锋 林金阳 LI Zhibing;LI Xiaoang;ZHANG Ran;XU Xiaodong;ZHENG Zhanfeng;LIN Jinyang(China Electric Power Research Institute,Beijing 100192,China;State Key Laboratory of Electrical Insulation and Power Equipment,Xi'an Jiaotong University,Xi'an 710049,China;State Grid Electric Power Research Institute,Nanjing 211000,China)

机构地区：[1]中国电力科学研究院有限公司,北京100192 [2]西安交通大学电工材料电气绝缘全国重点实验室,西安710049 [3]国网电力科学研究院有限公司,南京211000

出　　处：《高电压技术》2024年第10期4329-4337,共9页High Voltage Engineering

基　　金：国家电网公司科技项目(特高压大型充油设备故障快速保护及快速清除技术研究)(5500-202355357A-2-1-ZX)。

摘　　要：特高压换流变充油量大,内部短路故障时会产生高能油中电弧,出现大的机械冲击力并产生大量高温高压油气,容易导致油箱结构撕裂和爆炸起火。为此提出在换流变网侧并联SF_6间隙,1 ms内导通并形成低阻气体电弧通道,快速转移熄灭高弧阻油中电弧的防爆燃技术方案,将传统故障清除时间缩短约80%。油中电弧转移受故障电弧特性的影响,但相关研究主要针对小电流的短油隙(<50 mm),长距离高能油中电弧特性仍未阐明。该文等效模拟换流变网侧内部放电工况,设计了试验回路、试验方式、油中燃弧模拟装置和高精度试验测控系统,成功开展6种方式油中电弧转移熄弧试验,获得了油中电弧特性和间隙转移熄弧能力。试验中设计油隙长度为250~650 mm,覆盖换流变500 kV和750 kV网侧最小油隙长度,参考换流站短路电流水平设计试验电流为20~50 kA、参考换流变保护出口时间设计间隙触发时延控制油中燃弧时间为2~10 ms。6次试验中间隙均能在1 ms内转移熄灭油中电弧。试验结果分析表明,换流变网侧最小油隙起始弧压不低于10 kV,随着油隙长度增加,单位长度弧压略微增加;在10~50 kA级短路电流下,油中弧压受电流幅值影响很小。该试验表明了间隙转移熄弧防爆燃的可行性和防爆燃间隙设计的有效性,为特高压换流变防爆燃提供了新的解决方案。The internal short-circuit faults of extra-high-voltage converter with large oil filling can produce high-energy oil arc,accompanied by great mechanical impact and a large amount of high-temperature and high-pressure oil gas,which can easily lead to structural tearing of the tank and explosion.By paralleling a high pressure SF6 gap triggered by plasma injection at the grid side of the converter,a low-resistance gas arc channel can be formed after gap conduction within 1 ms,which is expected to realize the rapid transfer and extinguishment of arc in oil.By using this method,the traditional fault clearing time can be reduced by 80%.The feasibility of current transfer in oil is affected by the characteristics of the fault arc,whereas,the related research is mainly carried out for the short oil gap(a few millimeters to tens of millimeters)with small current,the arc characteristics in oil with long distance and high energy is still not clarified.Therefore,we equivalently simulated the internal discharge faults of the converter,designed a test circuit,test methods,an arc-firing simulation device,and a high-precision measurement and control system,and successfully carried out the tests of arc transfer and extinguishment under six different parameters.The results show that the SF6 triggering gap can realize the rapid transfer and extinguishment of the arc in oil,with 250~650 mm and 10~50 kA,within 1 ms.The minimum initial arc voltage of the oil gap is more than 10 kV,and the arc voltage of unit length increases slightly with the increase of the oil gap length.The arc voltage is slightly affected by the amplitude of short-circuit current.This paper verifies the feasibility of the technology scheme of transferring and extinguishing the arc by high pressure SF6 gap,and verifies the effectiveness of the design of the explosion protection gap,which provides a potential technical route for the explosion protection of UHV converter transformer.

关 键 词：油中电弧 等离子体喷射 SF_6间隙 电流转移 燃弧特性 

分 类 号：TM501.2[电气工程—电器]