Static compensator for fluctuating load power supply circuits - is typically for arc furnaces and has thyristors in antiparallel to absorb reactive power (BR 23.12.80)

TLDR: In this article, a thyristor-based static compensation is proposed for fluctuating load reaction power drawn from an AC distribution network, where short and open circuit conditions rapidly succeed each other.

Abstract: The thyristor based static compensation is for fluctuating load reaction power drawn from an AC distribution network. The load is typically an arc furnace where short and open circuit conditions rapidly succeed each other. The compensation circuit is intended to cope with rapid transients and to work in conjunction with normal more slowly reacting regulation circuits. The arc furnace etc.(1) is connected directly across the supply (4) and has an associated filter bank (5) across it removing harmonics. The compensator proper has a shunt capacitor bank (6) matching the reactive power handling capability of the circuit and a thyristor reactive power absorbing circuit (7). The thyristors are fired as a function of a reactive power sensor (11) output fed from the supply and a subtraction circuit (12), the sensor having a series active filter (13).