摘要
GIS局部放电在线检测中信号到达的前沿包含了重要的定位信息,但该电磁波信号在较狭小的管道中传播,使其波形变得十分复杂,采用峰值法、相关法等方法难有满意效果,因此提出了能量比函数法,即构筑一个滑动的窗口并求取窗体内的干扰能量和信号能量的比值来确定信号到达的前沿。在求取受强噪声干扰、经过多路传递的信号时延的计算上该法较其它方法简单实用,计算参数易于选择,算法稳定性高。算例表明,在信噪比较高的高压局部放电试验中,计算的结果与理论值非常接近,对于信噪比较低的试验波形,仍能够成功的求取信号的时间差。
The frontier of signals arrival contains some important information for the on-line monitoring system of partial discharges of GIS. The electromagnetic wave produced by partial discharges is transmitted in quite a narrow pipeline, and the discharge wave form becomes terribly complex, so the methods can not satisfy the needs of high signal-to-noise ratio. By setting a slip window on the time axis and dividing it into two units, calculating the average energe separately and making division, an energy ratio in the time window is gotten. This paper gives an arithmetic example（time window 34ns） about partial discharges of 110kV GIS. The result shows that, for the discharge signals with higher signal-to-noise ratio, the theoretical delay is 7.34ns while the calculating value is 7.6ns, which approaches greatly to the theoretical value; when there are fuzzy frontier of signals and lower signal-to-noise ratio, the calculating result is 9.2ns, 1.86ns beyond the theoretical value, and the error is within acceptable ranges. There will be little influence by choosing the length of time window for wave with higher signal-to-noise ratio, but it is sensible to wave with fuzzy frontier of signals. In common conditions the shorter window is better ,whose precondition is that there must be larger signal amplitude in the signal unit.
出处
《高电压技术》
EI
CAS
CSCD
北大核心
2007年第5期87-89,108,共4页
High Voltage Engineering
关键词
气体绝缘组合电器
局部放电
信噪比
电磁波
能量比法
时延估计
gas insulated switchgear（GIS）
partial discharge（PD）
signal-to-noise ratio
electromagnetic wave
energy ratio function
time delay
