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Shunt reactors are used to compensate the effects of line capacitance, particularly to limit voltage rise on open circuits or small loads. A magnetically controlled reactor is a device in which a DC pulsating through a special winding controls the inductive susceptance. Magnetically controlled reactors enhance transmission capability and save energy, especially in compact increased surge-impedance-loading power lines. The response of a thyristor-controlled reactor in voltage regulation to the voltage variations in a transmission line is faster than that of a magnetically controlled reactor. Although a magnetically controlled reactor can be designed to respond like a thyristor-controlled reactor in as little as 0.02 sec, the price of magnetically controlled reactor depends on its response time. In high voltage transmission lines, voltage variations are not sudden, so the slow response of the magnetically controlled reactor with respect to the thyristor-controlled reactor is not important. The main objective of this article is to compare magnetically controlled reactors and thyristor controlled reactors from a transient behavior point of view, and a detailed model of a magnetically controlled reactor reactor is used to illustrate the ideas presented throughout the article. [ABSTRACT FROM AUTHOR]

Semiconductor switches are subjected to high voltage and high current simultaneously during turn-on and turn-off. A snubber is a set of components that reduce the stress on the power semiconductors during switching intervals and transient. This article reports on the design of snubbers for modified bridge using gate-turn-off thyristor (GTO) by-pass valves. The snubber gives switching stress reduction. It has better performance than other equivalent snubbers described in the literature. Both theoretical and experimental results are discussed in detail. [ABSTRACT FROM AUTHOR]