配电网用灵活控制特快速开关方案及其触发导通特性

Scheme of Flexible Control Very Fast Switch and Its Discharge Characteristics for Distribution Network

配变重过载导致频繁停电和低电压问题逐年突出,由此引发的电压暂降和中断造成的损失和危害严重,传统开关设备快速控制和保护能力不足的问题愈加凸显。为此,分析了配电网备用电源快速切换的应用场景,首次创新性地提出了一种配电网用灵活控制特快速开关方案(flexiblecontrol very fastswitch,FCVFS),认为FCVFS工作性能主要取决于气体间隙开关的触发性能;进一步设计了气体间隙开关样机,并搭建了用于研究诱导击穿过程中喷射等离子体发展特性及其影响规律的触发试验平台。结果表明:SF6气体间隙开关触发导通过程分为预击穿和主间隙导通2个阶段,其中预击穿阶段起点火作用,此阶段的等离子体喷射高度峰值达6.1 mm,最大喷射速度为0.45 km/s,分别为主间隙导通时的4倍和2倍。增大脉冲电容值及其充电电压,气体开关触通过程中的等离子体喷射特性参数(喷射速度、喷射高度、喷射直径、喷射面积)渐进增大;提高工作系数,触发导通时延及主间隙导通时的等离子体临界喷射高度均渐进降低。空气与SF6气体开关的喷射等离子体发展过程存在明显差异,强绝缘、电负性气体SF6对喷射等离子体的发展具有明显的抑制作用。研究成果对于提高配电网快速关合技术的经济性、灵活性具有参考意义。

The problem of frequent power outages and low voltage caused by heavy overload of distribution transformers has become increasingly prominent year by year,thus the voltage sags and interruptions may result in serious losses and hazards.The problem of insufficient rapid control and protection capability of traditional switching equipment has become increasingly prominent.Consequently,we analyzed the application scenarios of rapid switching of standby power in distribution network firstly,and innovatively proposed a flexible control very fast switch(FCVFS)scheme for distribution network.It is considered that the working performance of FCVFS mainly depends on the trigger performance of gas gap switch.Furthermore,we designed the gas gap switch prototypes,and built a trigger test platform to study the development characteristics of the jet plasma and its influence during the induced breakdown process.The results show that the SF6 gas gap switch conduction process can be divided into two stages,namely,pre-breakdown and main gap induced breakdown.The pre-breakdown stage plays the role of ignition.In this stage,the peak plasma jet height(6.1 mm)and the maximum jet velocity(0.45 km/s)are 4 times and 2 times those of the main gap-induced breakdown.With the increase of pulse capacitance and charging voltage,the plasma jet characteristic parameters(jet velocity,jet height,jet diameter and jet area)gradually increase.Increasing the operating coefficient,the trigger delay of gas gap switch and the critical height of plasma jet decrease when the main gap breaks down.There are obvious differences in the development process of jet plasma between air and SF6 gap switch,and SF6 has obvious inhibitory effect on the development of jet plasma.The research results have reference significance for improving the economy and flexibility of the rapid closing technology of distribution network.