新型电容器组过电压保护器的现场试验研究

由于真空断路器在合闸过程中可能出现断口预击穿、合闸弹跳、合闸不同期等问题,而分闸过程中可能会出现单相、两相重燃、截流等问题。这些问题都会在真空断路器投切电容器组过程中产生严重的过电压。目前电容器组过电压保护通常采用的金属氧化物避雷器的I型接线并不能完全有效的限制真空断路器因上述问题而产生的过电压。为此设计出新型电容器组过电压保护器,与电容器组串联电抗器并联安装,并进行了现场投切电容器组试验。试验结果表明,对电容器组投切过程中因异常工况所造成的过电压确实起到了限制作用,特别是明显降低了电容器组切除过程中因截流和两相重燃所产生的较高的极间过电压,过电压保护器还可吸收因开关断口预击穿所产生的快波前过电压的能量。过电压保护器的安装,对系统内其它电容器组投切所产生的过电压也有抑制作用。

Field test study on the new type of capacitor bank overvoltage protector

Since the vacuum circuit breaker may appear the following problems in the switching-in process: the fracture before break-down , the switching-in springing, the switching-in unsynchronism, but in the switching-off process may have the problems such as single phase and two-phase restrike of arc and interception. These problems would cause heavy overvoltage in the process of the vacuum circuit breaker switching capacitor bank. At present, capacitor group overvoltage protector using the I type connection of metallic oxide arrester can't restrict effectively the vacuum circuit breaker coming into being overvoltage because of above-mentioned problems. So works out the new type of capacitor group overvoltage protector. The protector build in parallel connection with the reactance which connect to capacitor group in series, and carries out the field test on switching capacitor group. The results shows: the overvoltage caused by abnormal working condition has been restricted in capacitor bank switching-in process, especially reduces higher extreme overvoltage due to the interception and two-phase arc restriking in capacitor bank switching-off process. The overvoltage protector can absorb the energy of overvoltage in front of due to switching fracture before break-down caused quick wave, the installation of overvoltage protector also inhibites the overvoltage caused.by other capacitor bank switching-in in the system.