过电压保护间隙主动场击穿触发回路的研究

Study of Active Field-breakdown Trigger Circuit for Surge Protection Gap

为提高过电压保护间隙SPG的保护水平以及与后级过电压保护器件之间的能量配合,设计了基于场致触发的主动型过电压保护间隙,建立了过电压保护间隙的主动触发回路的电路模型,得到了回路元件参数的数学表达式,优选了触发回路的元件参数并进行了过电压保护间隙性能的实验验证。实验结果表明主动场击穿触发回路有效提高了过电压保护间隙的保护水平:当放电间隙间距d在0.55-2.1mm的范围内,主动型过电压保护间隙的冲击击穿电压Upulse与直流击穿电压UDC的压比K减小至被动型过电压保护间隙压比的50%左右;在放电间隙间距d=0.95mm的条件下,随着冲击电压峰值Um从3.6kV升高至6.5kV,Upulse由3.36kV上升至4.55kV,明显低于被动型保护间隙6.41kV的冲击击穿电压值。研究结果为主动型过电压保护间隙性能的提升、不同特性的过电压防护间隙的精确配合、过电压防护的机理及其应用技术的研究提供了理论与实验基础。

In order to improve the voltage protection level of the surge protection gap (SPG) and the coordination between the SPG and the surge protection devices (SPDs) in the secondary stage, we designed an SPG with an active field-breakdown trigger circuit, which was called the active SPG. The circuit model of the active trigger circuit was established and the mathematical expressions of the elements parameters in the circuit were obtained. In addition, the element parameters of the trigger circuit were selected to verify the performance of the active SPG. The results showed that the active field-breakdown trigger circuit effectively improved the voltage protection level of SPG. When the discharge gap distance d was in the range of 0.55 mm to 2.1 mm, the voltage ratio K of the active SPG, which was defined as the specific value of the pulse breakdown voltage Upulse and the DC breakdown voltage UDC, was 50% less than the SPG without an active trigger circuit. In the condition that the discharge gap distance d was 0.95 mm, the peak value of the impulse voltage Um increased from 3.4 kV to 6.5 kV, and the Upulse was increased from 3.36 kV to 4.55 kV. It was obviously lower than 6.41 kV, which was the Upulse of the SPG without an active trigger circuit. The results of the study can provide a theoretical and experimental basis for the performance improvement of the active SPG and the accurate coordination of the SPDs with different characteristics. Besides, they had also laid the foundation for the research of the mechanism and application of overvoltage protection.