Research on Lightning Surge and Protection of Indoor Wiring

This paper studies the overvoltages on the low voltage power supply system caused by lightning surge. We use a 1/5 scale iron model to simulate a building´s structure, a surge generator which can generate 1.2/50-8/20 mus waveform used as lightning surge, an SPD which constrain lightning surge under 1 kV, and some polyvinyl chloride cable. In this experiment, different load elements such as resistors, capacitors and inductors are applied, different lengths of cable, such as 1 m, 4 m, different ways of laying the cable and positions where surge is applied are studied. The results show the rule that capacitive load gender the highest overvoltage in all kinds of loads, and the overvoltage is higher when the capacitance increasing. It is also found that the longer the cable is, higher the overvoltage is, however this is opposite when the load is capacitive. Furthermore, the results of our digital simulation by PSCAD/EMTDC (electro-magnetic transients including DC) are compared with the experimental results, and they are well matched.