STATCOM, an efficient means for flicker mitigation

Flicker, annoying light intensity fluctuations, is a power quality problem caused by large time-varying loads like arc furnaces. State-of-the-art technology to reduce this kind of disturbances has so far been mainly the static VAr compensator (SVC) which however has a limited flicker mitigation capability. With the availability of forced-commutated components, the STATCOM becomes possible to be used as an efficient means to reduce voltage fluctuations causing flicker. In the paper, an arc furnace installation with a STATCOM is modeled dynamically both as a digital computer model in the program EMTDC as well as in a low-power analog real-time model. Flicker mitigation studies using an ideally optimal control algorithm for the STATCOM have been performed. In the algorithm, fluctuations in imaginary and real current are considered as well as fluctuations in the real current time derivative. The flicker reduction is demonstrated in the digital model and validated with the analog model.