摘要
限制过电压、降低绝缘水平、提高运行可靠性是特高压交流工程中非常重要的课题。避雷器的保护水平与其额定电压Ur紧密相关,通常避雷器的Ur需大于系统最大工频暂时过电压值(TOV)。但是为了满足特高压变电站设备的过电压和绝缘水平的苛刻要求,避雷器的保护水平又要尽可能低。降低特高压避雷器保护水平的方法有降低压比和降低避雷器额定电压2种方法。尽管特高压避雷器已经采用4柱电阻片并联结构等多种方法来降低压比,但受技术、经济条件等限制,压比不可能大幅度降低。选择MOA额定电压是一项复杂的辩证科学,需在上述矛盾的两方面找到平衡点。为此通过大量的试验分析了特高压避雷器耐受TOV的极限能力,掌握了在不影响保护水平的情况下特高压避雷器自身的安全裕度,证明了当前特高压用避雷器的安全性和可靠性,并论证了避雷器额定电压存在进一步降低的可能性。
Ultra-high voltage （UHV） AC line systems have high voltage and huge-transmission capacity. It is an important issue to limit the over-voltage, lower insulation level and increase operational reliability. The level of protection closely related to the surge arrester （MOA） rated voltage Ur. Generally, MOA rated voltage Ur must he greater than the value of system maximum temporary frequency-overvoltage （TOV）. On the other hand, in order to meet the demand requirements of UHV over-voltage and insulation level of substation equipment, the protection level of MOA should be as low as possible. There are two methods to reduce the protection level of MOA： reduce the ratio between residual voltage and the reference voltage, reduce the rated voltage of MOA. Although UHV MOA have adopted four-way parallel structures to reduce the ratio, but restricted by the technical and economic conditions, the ratio can＇t be significantly reduced. Select MOA rated voltage is a complex dialectic of science, required to find a balance point in the above two aspects. This paper analyzed the utmost TOV withstand ability of UHV MOA through a large number of test data, predominated the UHV MOA＇s own safety margin, proved that the safety and reliability of the UHV surge arrester use for the project, and then demonstrated the possibility to reduce the rated voltage of UHV MOA.
出处
《高电压技术》
EI
CAS
CSCD
北大核心
2010年第1期144-152,共9页
High Voltage Engineering
基金
国家电网公司重点科技项目(SGTGY[2008]614)~~
