This Variable Shunt Reactors are used in applications where the range of the reactive power to be adjusted is large but the regulation is not dynamic, that is, the change in the reactive loading is gradual.
Dynamic regulation will require Static VAr compensators with thyristorised controls.
Variable Shunt Reactors are fitted with reactors whose values can be adjusted through tappings. These tappings are selected using motorised controls. These adjustments can be made on load.