Optical and electrical acquisition of discharge phenomena on air gaps

在ATP/EMTP等仿真软件中，只有不准确的模型来模拟雷击下电力系统的快速暂态过程。对架空线路雷击闪络绝缘子的物理过程缺乏了解是该软件的主要不足之处。因此，在计算绝缘配合时，需要考虑安全系数等标准参数。因此，本研究项目的主要目标是通过测量电力系统中雷击绝缘子闪络的现有过程来克服这一问题。此外，应对测量结果进行物理解释。为了提供对闪络的物理理解，将使用一种开发的带有棒-棒电极的测量系统。绝缘子上最频繁的闪络可以通过棒-棒电极的布置来再现，然后可以同时测量脉冲发生器上的电压和两个电极上的电流。这里的主要挑战不仅是闪络电流的测量，而且是预放电电流的测量。在进行各种测量后，将计算出闪络的电荷量、载流子在气隙中的传播以及施加电压的极性等参数。此外，还将其与已经研究过的杆状电极布置进行比较。借助经验和统计调查，应识别和描述标准雷电冲击电压下杆状电极布置的闪络的各个阶段。这些结果是对闪络物理过程进行详细模拟的基础。本研究的进一步目的是提供关于非标准振荡雷电冲击电压下闪络过程的基本知识，以便研究实际发生在绝缘上的雷击闪络。对于这一建议，应进一步构建测量体系，并由该研究项目的基金予以支持。因此，应由所开发的系统进行测量，以识别标准和非标准振荡雷电冲击电压下的放电过程的差异。

In simulation software like ATP/EMTP, there are only inaccurate models to simulate very fast transients in power system due to lightning strikes. The lack of knowledge about physical processes in case of flashover on insulator caused by lightning strike on overhead lines is the main imperfection of such software. Therefore, some standard parameters like a safety factor are considered for insulation coordination calculations. Hence, the main goal of this research project is to overcome the issue by measuring the existing processes in case of lightning flashover on insulator because of a lightning strike in power systems. Moreover, the measurement results should be physically interpreted. To provide a physical comprehension about lightning flashover, a developed measurement system with a rod-rod electrode will be used. The most frequent flashover on insulators can be reproduced by a rod-rod electrode arrangement and thereafter, voltage at the impulse generator and the current at both electrodes can be synchronously measured.The main challenge here is not only the flashover current measurement but also the pre-discharge current measurement. After performing a variety of measurements, the parameters of flashover such as charge quantity, propagation of charge carriers in air gap and the polarity of the applied voltage will be calculated. Furthermore, it will be compared to/with the rod-plan electrode arrangement, which has been already investigated.With the aid of empirical and statistical investigation, the individual phases of flashover for rod-rod electrode arrangement under standard lightning impulse voltage should be identified and described. These results are the base for a detailed modelling of the physical processes during a lightning flashover.Further goal of this research is to provide a basic knowledge about processes under non-standard, oscillatory lightning impulse voltage in order to investigate the lightning flashover that occurs on insulation in reality. To this propose, a further measurement setup should be constructed, which should be supported by the fund of this research proposal. Consequently, measurements should be carried out by the developed system in order to identify the differences of discharge processes under standard and non-standard, oscillating lightning impulse voltage.