Research on energy coordination between multi-level surge protective devices with the transmission line theory

摘要

Surge protective device is widely used in the lightning protection of electric appliances. In order to meet the withstand voltage level of those protected devices, multi-level surge protective devices are applied in the practical situation. Therefore, the optimal choice of decoupling elements is vital to realize the energy coordination between multi-level surge protective devices. This paper intends to expatiate on the process of coordination between these low-voltage multi-level surge protective devices, which is based on the transmission line theory. Through a series of experiments, we found the transmission line theory could be applied to describe the transmission process of lightning wave in the low-voltage system; When a 5-meter-long wire whose inductance is 5.6 micro-henry was used as the decoupling element, the average shunt ratio between multi-level surge protective device in the first level and multi-level surge protective devices in second was about 0.9: 0.1; upon the experimental results, it was proposed that two voltage limiting type multi-level surge protective devices had a better performance to clamp the overvoltage, which has a certain reference value in the practical application.