Shunt reactors

Shunt reactors

Shunt reactors improve voltage stability and power quality

ABB’s leading position in high and ultrahigh-voltage shunt reactors stems from an uncompromising commitment to quality, innovation and technical excellence. ABB shunt reactors provide innovative technology to meet the needs for voltage stability, power quality and integration of renewable energy.

The networks for transmitting and distributing electrical energy face new demands due to changes in power generation and load structure. Both commercial and environmental drivers contribute to this demand, as does power quality. Dynamic and time varying effects associated with renewable energy also influence networks. The active power flow in the network and the balance of reactive power must both be regulated to maintain voltage stability – a key to power quality in HV transmission. The voltage level in the grid must also be kept within specified limits regardless of the loading, which varies with time (hourly, daily or seasonally).

Shunt reactors are cost-effective and reliable

Shunt reactors (SR) are commonly used to compensate reactive power and to maintain voltage stability. Traditionally, SRs have fixed ratings with no means of voltage regulation. If regulation is needed, fixed reactors are switched in and out along with load variations. However, the resulting large steps in reactance lead to step changes in the system voltage level, especially if the grid is weak. This creates power quality issues and places stress on the breakers.

Wherever power quality is essential, variable shunt reactors (VSR) are an attractive alternative to fixed reactors. VSRs have regulation capability and can interact with other regulating devices such as Static Var Compensators (SVC).

VSRs based on transformer tap changers have a regulation speed on the order of minutes between the extreme positions. As load variations occur slowly, i.e. mostly on the order of hours or longer, VSRs based on tap changer technology prove to be the most cost-effective and reliable technology for controllable shunt reactors.

Vol. 7 Issue 1