A high current engineers approach to a high voltage impulse measurement problem

It is conventional to use power utility high-voltage test laboratories to perform lightning puncture strength tests on aircraft components such as radomes. When impulse testing power utility items, there is no interest in the voltage across or current through the item under test after failure. When testing aircraft radomes however, as the air breaks down long streamers are formed and these draw a comparatively large and highly nonlinear current. Voltage measuring channels set up for power utility applications give large errors with such nonlinear current in the circuit. This paper describes the measuring of circuit parameters of a large impulse generator and subsequent use of these in computer modelling of the circuit. The model is compared with actual test results. Modifications to the voltage measuring channels are proposed in order to correct the errors. The effectiveness of the modification is measured on a simulated circuit and the results are compared computer predictions.