Application of inverter-based systems for peak shaving and reactive power management

This paper presents two different applications of inverter-based equipment in utility electrical systems. The first application is a Distributed Energy Storage System (DESS) utilizing sodium-sulfur (NaS) batteries for peak shaving to mitigate capacity constraints. The installation includes NaS batteries, a power conversion system, and a step-up transformer which connects the system to a 12-kV feeder. The second application is a hybrid reactive-power compensation system consisting of an inverter-based compensator and mechanically switched capacitors designed to meet the reactive power requirements of a 90-MW Wind Power Plant (WPP). This installation includes an inverter-based compensator, step-up transformers, and mechanically switched capacitors located in the collector substation of the WPP. Each of these applications will be presented as a case study, including details on application considerations, system configuration, installation and start-up, as well as lessons learned.