Design and construction of a dynamic system for step and touch voltage measurements for grounding systems

This article deals the process to design, to construct and to test step and touch voltage equipment applied in 15 kV grid and grounding systems. The equipment injects two waveforms current: the first one is a sinusoidal pulse of 1530 Hz, the second one is a 10/350 μs impulse both have 15 A as peak value using device as a Fly Back, an air coil inductor, a small resistance, a single high voltage capacitor and a car battery to supply electric energy. The mean voltage measurement systems is a capacitive divider and for current is a shield resistor until 20 kV and 100 A respectively with two different kind of output terminal for digital voltmeter or oscilloscope. According to the experimental results it is possible to measure a small grounding net or combination between rod and ring electrodes with grounding resistance in the range of 1 Ω to 20ΩΩ When the grounding resistance is increased, the peak of current decrease, although is possible to measure the touch voltage, the step voltage, its spatial distribution, a transferred resistance and the equivalent grounding resistance.