About: Voltage control and reactive power management

Voltage control and reactive power management are two facets of an ancillary service that enables reliability of the transmission networks and facilitates the electricity market on these networks. Both aspects of this activity are intertwined (voltage change in an alternating current (AC) network is effected through production or absorption of reactive power), so within this article the term voltage control will be primarily used to designate this essentially single activity, as suggested by Kirby & Hirst (1997). Voltage control does not include reactive power injections within one AC cycle, these are a part of a separate ancillary service, so called system stability service. The transmission of reactive power is limited by its nature, so the voltage control is provided through pieces of e