Influence of network voltage level, converter topology and integration of energy storage on the power losses of STATCOM devices

This paper presents an analysis of power losses in 2.1 MVA static synchronous compensator (STATCOM) devices and STATCOMs with integrated energy storage (ESTATCOM). The analysis was carried out by means of computer simulations, with the main focus on studying the influence of network voltage level (690 V - 2 kV), voltage source converter (VSC) topology (2-or 3-level) and energy storage integration on the losses of STATCOMs. Power loss models for LCL-filters, VSC bridges, DC/DC converter power stages and inductors, as well as supercapacitor banks were developed. According to the results the losses are minimized when a 3-level VSC is used, and the compensator is connected to the network voltage of 690 V, and the ESTATCOM energy storage is connected to the dc link with two separate DC/DC converters. This occurs because the system converters can be implemented with IGBTs of lowest rated voltage.