Device for earth fault current compensation in power networks

A device comprising at least two controllable reactance elements arranged to compensate a single phase-to-earth fault current in a power network with a power transformer, wherein the at least two controllable reactance elements are each connected with one side to two different voltages of a three phase voltage source which is synchronous with the power network, and that the at least two controllable reactance elements with their other side are jointly connected to neutral of the power network, wherein the at least two controllable reactance elements are individually controllable by a control unit designed to control neutral voltage of the power transformer with respect to amplitude and phase in relation to the power transformer's own voltage system,

• wherein said controllable reactance elements are made up of two tuneable capacitor banks, and
• wherein the at least two reactance elements are individually controllable to control the neutral voltage to eliminate a drive voltage of an earth fault current.