基于高速数字电路的PD UHF信号纳秒级陡脉冲源研制

Development of a nanosecond pulse generator for simulating PD UHF signal based on high-speed digital circuit

超高频法是目前电力设备局部放电在线监测广泛使用的监测方法,超高频电磁信号的定量、定位研究需要稳定可靠的UHF信号模拟发生装置,针对这一现实需求,文章设计了一种基于数字电路的纳秒级脉冲源,用于产生PD UHF模拟信号。文章详细分析了利用数字电路产生陡脉冲的原理,选用简单的高速逻辑器件构建了脉冲发生电路,并采用虚拟仪器产生频率可变的方波信号作为脉冲源的触发信号。用Pspice仿真分析了门电路的脉冲响应特性,并搭建了试验电路进行性能测试。实验结果表明,该脉冲源产生的陡脉冲信号幅值可达2 V,脉冲重复率为50 k Hz-20 MHz,上升陡度为1 ns,脉宽为3 ns,能有效模拟PD UHF信号,并进行相关的局部放电实验。

The method of ultra-high frequency （UHF） is widely used for the PD online monitoring of electrical equip-ments, which requires a waveform generator of high stability and reliability to simulate UHF signals when it comes to the location and quantitative analysis of those signals. In order to satisfy this need, we design a nanosecond pulse gen- erator based on digital circuits, and its signal is able to imitate the real UHF signals of PD. In this paper, we analyze the principle of how to take advantage of digital circuits to create steep pulses specifically and employ virtual instru-ment to produce square wave signals with variable frequency and amplitude as trigger signals of pulse origins. Be-sides, Pspice is used to simulate the pulse response characteristics of gate circuits, and we establish experimental cir-cuit platform to test its performance. And just as the experimental results show, this pulse origin can generate a type of steep pulse, whose magnitude is up to 2 V, repetition rate ranges from 50 kHz to 20 MHz, rising time is Ins and pulse width is 3 ns, and we carry out relative PD experiments by it and find such pulse is able to simulate UHF signals of PD effectively.