Static var compensators

Claim 1

In a power transmission system having a static var compensator (SVC) connected at a line node between a source and a fluctuating load for compensating for changes in reactive power resulting from load current fluctuations in response to a load fluctuation, and a current detector for monitoring load current fluctuations, said static var compensator including a capacitor and a first reactor connected in parallel at a common node and having large rated capacities for producing and absorbing reactive power, respectively, and a static switch means for controlling current flow through said first reactor so as to control the reactive power produced, the improvement in the SVC comprising: a second reactor means separate from line reactance disposed between the line node and the common node for providing, in combination with said capacitor and said first reactor, a maximum leading reactive capacity so as to effectively reduce the capacities thereof, said second reactor means increasing the reactive power produced by said capacitor when the reactive power absorbed by said first reactor is low and decreasing the reactive power produced by said capacitor when the reactive power absorbed by said first reactor is high.