Performance analysis of conventional STATCOMs and STATCOMs with energy storage in electric arc furnace applications

This paper analyzes the performance and power losses of 2.1 MVA conventional STATCOMs and STATCOMs with energy storage (ESTATCOM), in electric arc furnace applications. The research was conducted by computer simulations with Matlab Simulink software. According to the simulation results load compensation reduces the required current rating of the supply grid transformer and cables by approximately 30 %, and the maximum drop of the reference point (RP) voltage to 2 % compared to 15 % caused by the non-compensated case. The conventional STATCOM attenuates the RP voltage flicker by a factor of 5.9 and the ESTATCOM by a factor of 11.7. The voltage source converters (VSC) of both compensators could be designed for the same rated current, despite the active power compensation capabilities of the ESTATCOM. The system losses are minimized when a 3-level VSC is used instead of a 2-level VSC, and the compensating device is connected to the lowest studied network voltage of 690 V. The energy storage system losses are minimized when the energy storage is connected to the dc link using two separate DC/DC converters instead of a large single converter. This occurs because the system converters can be implemented with IGBTs of lowest rated voltage.