| Summary: | 碩士 === 國立成功大學 === 電機工程學系碩士在職專班 === 102 === Lightning rod is the most common lightning protection equipment. If lightning grounding lead is bending, the inductance of the wire will increase. When the lightning current through the wire, the voltage drop of the bent wire is larger than that of the straight wire. If the voltage drop exceeds the dielectric strength of the wire, the flashover will be occurred. And, the outer walls of buildings and the covered wire duct will be destroyed too. In this thesis, the simulation result of lightning grounding lead on different bending situations is obtained with COMSOL Multiphysics .
In this thesis, 100 mm2 PVC cable for the lightning rod grounding lead model, length of 5 meters, 40kA 8/20μs lightning wave are adopted. And, the direction of the current is downward, medium is radius 1000mm air. The inductance and voltage drop differences will be analyzed for bending angle of 90 degrees, radius of 10 cm, 20cm, 30cm, 50cm, 70cm, 100cm and straight wire model. Simulation results show that all bent wire inductance and voltage drop were bigger than that of the straight wire. And, the smaller the bending radius of the wire, the greater the inductance and voltage drop of the wire. So no any bending poocessis the best ideally lightning grounding lead install connected to ground rods downward. However, if the construction is necessary to bend the wire, as far as possible to increase the bending radius of the wire.
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