Transients in the low-voltage power-distribution circuits: effects of capacitive loading and dependence an distance

The effect of capacitive loading on a transient excited in a low-voltage power distribution line section is analyzed in terms of frequency and amplitude of the two damped sinusoidal oscillations that are seen to describe the complete transient. The frequency range involved is from a few kHz to over 100 kHz. Closed form expressions for the amplitudes and frequencies of the two components are derived. The relative importance of the capacitance values and the role of the position of the load along the line are described, thus allowing evaluation of the reduction of the loading effect with distance. Large capacitors such as those used for power-factor correction are shown to constitute essentially a short circuit for the transient disturbance. The experiments confirm the theoretical findings.