Characterization of Pressure Rise due to DC Arc Simulating Lightning with Puncture Breakdown in Long Cylindrical Space under Supposition of the Inside of a Wind Turbine Blade

Abstract

While wind turbine generators have widely spread as one of the renewable energy sources, lightning protection for the wind turbine generators has been becoming a very important issue because lightning damages of them may cause the economic losses and the public disaster. As one of the studies for such lightning protection, internal arc tests for wind turbine blade models, which simulates the lightning penetration into a wind turbine blade, were carried out using a short-circuit generator. On these tests, length of the wind turbine blade model and waveform of the arc current are dominant test parameters because they are thought to be influential factors related to the pressure rise in a wind turbine blade. In this paper, the CFD calculations of pressure rise due to a DC arc in a closed space are conducted, where the closed space is a long cylinder as simplifying the inside of a wind turbine blade. From a result of the CFD calculations, we clarified a dependence of the internal pressure rise not only on the length of cylindrical space, which varies from 2 to 40m, but also on the waveform of direct current, which varies from 2 to 8kA with a constant electric charge of 100C.