Stable triggering of acquisition devices is critical to accurately measure electromagnetic transients, especially for very fast transient overvoltages (VFTOs). A highly stable and low-cos t self-trigger method for transient measurement is proposed. An integrated low-voltage arm module was developed to synchronously realise the triggering and VFTO measurement. The trigger branch was developed using a high-pass filter. This component obtained the high-frequency component of the VFTO to trigger the oscilloscope. The trigger branch was integrated with the measurement branch through an impedance converter. An attenuator was implemented before the impedance converter to avoid overvoltage damage to the chip. The circuit parameters of the attenuator were optimised to alleviate the disturbance of the measurement branch. The calibration results demonstrated that the ±1 dB bandwidth of the measurement branch in this system ranged from 11.8 Hz to 105 MHz. The low cutoff frequency of the trigger branch was 710 Hz. The VFTO waveforms generated by the operation of a disconnector in a real 252 kV gas insulated switchgear were measured using the proposed system. The test results verified that the self-trigger measurement system can provide stable trigger signals and accurately measure the VFTO waveforms.

中文翻译：

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一种低成本、高性能的高压瞬态测量自触发方法

采集设备的稳定触发对于准确测量电磁瞬变至关重要，尤其是对于非常快速的瞬态过电压 (VFTO)。提出了一种用于瞬态测量的高稳定性和低成本的自触发方法。开发了集成低压臂模块，同步实现触发和VFTO测量。触发分支是使用高通滤波器开发的。该元件获取VFTO的高频成分来触发示波器。触发分支通过阻抗转换器与测量分支集成。在阻抗转换器之前实现了衰减器，以避免芯片过压损坏。优化了衰减器的电路参数，减轻了测量支路的干扰。校准结果表明，该系统中测量支路的 ±1 dB 带宽范围为 11.8 Hz 至 105 MHz。触发分支的低截止频率为 710 Hz。使用建议的系统测量实际 252 kV 气体绝缘开关设备中隔离开关操作产生的 VFTO 波形。测试结果表明，自触发测量系统能够提供稳定的触发信号，准确测量VFTO波形。