特高压电晕笼的多分裂导线电晕损失测量系统

Corona Losses Measurement System of Bundle Conductor Using UHV Corona Cage

为准确、连续地测量特高压分裂导线电晕损失,对传统的电桥法进行改进并根据特高压电晕笼机械与电气特性,结合光纤传输技术,采用混合型光供电电子式电流互感器测量特高压电晕笼中分裂导线电流;采用电容分压器测量特高压电晕笼导线试验电压。基于虚拟仪器技术,采用瞬时功率法研制了一套光纤数字化特高压电晕笼电晕损失测量系统,经校验该系统满足0.2级准确度要求,能够较为准确测量电晕笼导线电晕损失。对晋东南-南阳-荆门特高压交流试验示范工程用8×LGJ-500/35导线开展起始电晕特性和电晕损失特性试验研究结果表明,在干燥条件下分裂导线起晕场强为27.64 kV/cm(峰值),正常运行电压下不会出现全线起晕的情况;20 mm/h大雨条件下分别对应特高压交流单回试验线段边相和中相导线表面场强,电晕笼导线电晕损失为50.83 W/m和59.73 W/m;可以应用该系统进一步研究我国特高压交流输电线路电晕损失规律。

In order to measure corona losses of UHV bundle conductor accurately and continuously, according to mechanical and electrical characteristics, combined with optical fiber transmission technologies, hybrid optical power of electronic current transformer （ECT） is adopted to measure current of bundle conductors in UHV corona cage, standard capacitive voltage divider is adopted to measure test voltage of UHV corona cage, and based on virtual instrument technology, instantaneous power algorithm is adopted to develop an optic fiber digital UHV corona cage corona losses measurement system. Error of voltage measurement and current measurement of this system, is measured and calibrated. With regard to 8× LGJ 500/35 bundle conductor, adopted in Jindongnan-Nanyang-Jingmen UHV AC Demonstration Project, onset corona characteristics and corona loss characteristics are researched, and test results show that, this system meets the requirement of 0.2 level accuracy, and is able to measure corona loss accurately; Onset field strength in dry condition is 27.64 kV/cm （peak）, whole line in corona wouldn＇t happen in normal operation voltage, and in heavy rain condition （20 mm/h）, according to surface field strength of lateral phase and central phase bundle conductors respectively, corona losses of bundle conductors in the UHV corona cage are 50.83 W/m and 59.73 W/m; And this system can be set up for further study on UHV AC transmission line＇s corona losses law in China.