Simulations and tests with impulse current generator

Summary

The impulse current generator commonly used in high-voltage laboratories consists basically of a RLC (resistor, inductor and capacitor) circuit connected in series. In this type of circuit, the impulse current waveform depends of the RLC equivalent values. As the test object is part of the circuit, the waveform of the impulse current depends strongly of electrical characteristics of the object under test. Thus, when dimensioning the impulse current generator circuit elements, the test object should be considered. This work has the purpose to show a way of modeling an impulse current generator in electromagnetic transient simulation programs, considering the characteristics of the generator and test object. Simulations are performed in ATP software (Alternative Transients Program), with only the impulse current generator (no test object) and with two test objects, a linear resistor and a zinc oxide (ZnO) block (surge arrester), the latter being modeled for a nonlinear resistor. The nonlinear voltage-current characteristic (V-I curve) was obtained in the manufacturer's datasheet. The simulator is validated based on the results of mathematical expressions deducted from the generator electric circuit and impulse current measurements. The impulse current waveforms, measured, simulated and calculated were compared and indicated high correlation. Variations were observed in impulse current waveforms for different test objects, which suggest that the use a simulator before the electric test is a great option to predict the current response of the generator.

Additional informations

Authors

Brito Valdemir S, Nobrega Raphael B, Lira George R S, Costa Edson G, Maia Marcelo J A