Digital control by the discrete systems of reactive power compensation in ship electrical power plants

Abstract

The reactive power required to create the electromagnetic fields of electric motors, transformers and converters worsens the performance of the power system, the total current of the generator, transformers and cable lines must be significantly increased in relation to the required active load current by an amount that proportionately increases the installed capacity of the electrical equipment and the cross section cable connections. Instead of single work with full load, the parallel operation time of generating units with underload is increased to provide excess full power of electric consumers, including their reactive power. Solving the problem of energy saving, reducing the reactive power consumption allows capacitors Reactive Power Compensation Devices (RPCD). Varying the capacitance of the stages of the compensating capacitors, it is possible to fully compensate the reactive current of the actively inductive load of consumers. An analog (continuous) change in the capacitance of high-power capacitors is still an unsolved technical task. In most power plants, the capacity of capacitors varies stepwise, by connecting a different number of capacitor sections. This article is devoted to the investigation of RPCD, consisting of several blocks of compensating capacitors that are switched to the powernet independently of each other by means of high-speed thyristor switches. The change in the capacity of compensating capacitors in RPCD in power plants is accomplished by connecting a certain number of sections of capacitors. In this case, the capacitance value changes stepwise, i.e. discretely according to the adjustable value. The capacitance of each capacitor section, the number of sections of capacitors and the algorithm of their switching to the network are the technical parameters of the discrete system of reactive power compensation. Analysis of these parameters and their optimization is the task of this article.