Application of a grid scale energy storage system to reduce distribution network losses

Recent progress in advanced energy storage systems (ESS) and their relative technological maturity imply a promising future for energy storage. As a consequence, the use of stored energy to support and optimize the generation, transmission, and distribution subsystems has been grown up worldwide. One of the ESS applications is using them for load leveling. Since network losses is a square function of current, shifting load from peak to off-peak periods can potentially reduce system losses. This paper gives a quantitative survey of the possible reduction in losses, for a situation where distribution feeder load is shifted in time but not reduced. Load leveling practice will be done by an ESS unit installed in the distribution substation. Various factors governing loss reduction such as transformer side installation (MVlLV) are analyzed. Also, required ESS characteristics like Ampere-hour (Ah) capacity, current, power, and charge /discharge speed to ideally leveling the load are presented. Simulation results show that besides loss reduction, load leveling has a significant impact on network capacity. In other words, shifting peak load can defer investment plans considering load growth in the near future.