Simulated electric arc furnace voltage flicker mitigation with 3-level current-controlled STATCOM

This paper examines electric arc furnace voltage flicker mitigation with a compensation system consisting of a shunt-connected 3-level STATCOM and two passive filter banks tuned to filter 2^nd and 3^rd current harmonics. The STATCOM compensation performance is mainly determined by the current control method used. Thus the study examines four different current control methods, i.e., one linear current control method and three nonlinear hysteresis current control methods, and compares their operation in a flicker compensation application. System stability is also analyzed, because instability may result from interaction between the passive filter banks and STATCOM. The simulation results show that the compensation system examined effectively mitigates the flicker problem. The main advantage of the linear current control method is fixed switching frequency, which makes it a preferable solution if LCL supply filter is used. However, the hysteresis current control methods examined offer better dynamic response, smaller current control delay and, thus, larger system stability margins.