110kV变压器中性点水流保护间隙与避雷器并联保护方式  

Protection Mode of Parallel Connection of Water Flow Protection Gap and Arrester for Neutral Points of 110 kV Power Transformers

作　　者：李博江[1] 文习山[1] 严玉婷 蓝磊[1] 李晓萍[1] 鲁海亮[1] 

机构地区：[1]武汉大学电气工程学院,武汉430072 [2]深圳供电局,深圳518001

出　　处：《高电压技术》2014年第3期772-779,共8页High Voltage Engineering

基　　金：中央高校基金科研业务费专项资金(2012207020206);国家重点基础研究发展计划(973计划)(2009CB724500)~~

摘　　要：为克服传统保护方式的缺陷,提出了1种水流保护间隙和避雷器并联的110 kV变压器中性点新型保护方式。在系统发生非全相运行故障或者单相接地短路且失地时,水流保护间隙形成且立即被击穿(即水流保护间隙动作),从而保护变压器中性点绝缘和避雷器。在雷电过电压下,由避雷器动作泄放雷电流,水流不会喷出,不会形成水流间隙,间隙不会动作;在其他过电压下,水流不会喷出,间隙和避雷器均不动作。对已研制成功的整套水流保护间隙与避雷器并联新型控制系统进行大量试验,研究结果表明:水流保护间隙的工频放电电压和放电分散性都低于同等距离的空气间隙,当工频电压升高到快接近放电电压时,在高压电极头部会产生强烈的电火花。水流保护间隙和避雷器并联新型保护方式可以可靠工作,更有效保护变压器中性点绝缘。To overcome disadvantages of the traditional protection modes, we proposed a new one for neutral points of 110 kV transformers, which has water flow protection gap and arrester parallel connection. In this protection mode, when faults of an open-phase operation happen or a single-phase is grounded with system being ungrounded, water flow gap will be formed and immediately breakdown （i.e. the water flow gap acts）, thus the insulation of neutral points and arrester can be protected. Under the lightning overvoltage, lightning current will flow away through arrester so there is no water flow spout and hence no water flow gap and no gap action. Under other kinds of overvoltage, no water flows and spouts, and neither water gap nor arrester acts. Moreover, we successfully developed a control system with parallel-connecting water flow protection gap and arrester, and completed a large number of tests on the system. The test results show that the power-frequency discharge voltage and its dispersion of the water flow gap are lower than those of air gaps of the same length. When the power-frequency voltage gets close to the discharge voltage, strong electric sparks will be generated at the head of high voltage electrode. The new protection mode can work in accordance with the designed principle of oper- ation reliably, and effectively protect the insulation of transformer neutral points.

关 键 词：变压器 中性点 水流保护间隙 新型控制系统 电火花 放电电压 

分 类 号：TM863[电气工程—高电压与绝缘技术]