Required VSC efficiency for zero net-loss distribution network active compensation

Abstract

Active compensation of distribution networks with medium-voltage power electronics can result in a reduction in feeder electrical losses if operated correctly, however losses are incurred in the active compensator itself when operating. This paper aims to define a lower boundary for the total efficiency of such a compensation system in which the compensator will offset its own operating electrical losses. If the compensator efficiency is improved beyond the determined boundary, any additional reductions in losses due to compensation will be of net benefit to the utility employing these devices, i.e., the break-even efficiency which gives zero net electrical losses. The reduction in feeder losses also implies reduced stress on electrical assets which may be of further benefit to utilities. Different categories of network topologies with different numbers of compensators have been considered as part of this study. The total amount of loss-reductions possible with compensation are presented (in MWh/year), and later the worst and best case break-even efficiency requirements are presented. In addition, the additional reduction in network losses due to the installation of distributed generation is considered. Since active compensation with power electronics can allow for increased levels of distributed generation, some of the additional loss reduction can be attributed to the presence of the compensator itself, thereby relaxing total compensator efficiency requirements.