Method and a device for controlling a secondary voltage in a transformer device connected to a power network and comprising an on-load tap-changer

摘要

In a method for controlling a secondary voltage (US) in a transformer device connected to a power network with a given system frequency (f₁), which transformer device comprises a tap-changer (TC) which, in dependence on a supplied control signal (RCS), influences the voltage ratio (RAT) of the transformer device, a voltage variable (u_E) is formed in dependence on the secondary voltage. The voltage variable comprises at least one first control component (u₁, &phgr;₁) which represents a fundamental component of the secondary voltage, and a control quantity (EPV, EEV) is formed in dependence on the voltage variable. The control signal is formed in dependence on a deviation (DPV, DEV) between the control quantity and a given reference value (PVR, EVR) therefor and is supplied to the tap-changer. The actual fundamental frequency (f₁*) of the power network is continuously sensed and the voltage variable is formed in dependence thereon.