Effort to formulate voltage modulation constraints in ship-electrical systems with pulsed loads

Abstract

One of the most significant power supply quality problems in ship electric networks is `voltage and frequency modulation`. It is caused by the operation of certain electric loads, known as `pulsed loads`, which require regularly or randomly repeated high power for short time intervals. To the best of the authors` knowledge, no well-based theoretical analysis of the phenomenon exists, while regarding standards, any existing constraints in the operation of pulsed loads are not properly explained. In a series of two companion papers the theoretical analysis of the phenomenon is made; the first paper investigates frequency modulation, whereas this second paper deals with the analytic estimation of voltage modulation. First the theoretical explanation of the voltage modulation is established highlighting the critical parameters affecting it. Next, a suitable constraint inequality is derived comprising several inherent parameters of the ship electric system affecting voltage modulation. Furthermore, a sensitivity analysis of the particular effect of each of these system parameters is made. The proposed method can be a useful guide for setting limits via standards and a design tool for ship electric power systems enabling the performance of investigation studies of acceptable pulsed loading without the need of complicated simulation models.