The shunt reactor could be permanently connected or switched via a circuit breaker. To improve the adjustment of the consumed reactive power the reactor can also have a variable rating. If the load variation is slow, which it normally is (seasonal, daily or hourly), a variable shunt reactor (VSR) could be an economical solution for some customer applications.

 Most oil-immersed shunt reactors manufactured by ABB are based on the so-called gapped core concept. This technical concept is based on the core type technology that has been used within ABB since the beginning of the 1970s. The concept of the design is to minimize losses, sound and vibration. Design similarities with large power transformers permit an efficient use of ABB’s long experience of building large transformers, for instance in the areas of insulation build up, production handling and so on.