Patent ID: 7956596

Claim:
A method of coordinated voltage control using voltage control devices serially connected between a transmission substation and a load, comprising: controlling a local voltage level (U S 3 , U S 4 ) in response to control commands issued to a first and a second voltage control device by a respective first and second voltage control unit and based on control parameters which are dead band (DB 3 , DB 4 ) and/or time-delay (TD 3 ID 4 ) characteristics; measuring an instantaneous value of a voltage level (U P 4 ) at a location in-between the first and the second voltage control device; issuing, by the second voltage control unit, control commands for the second voltage control device; calculating a deviation of the measured instantaneous value of the voltage level (U P 4 ) from a voltage level reference value (U P ref ); and updating values of the control parameters (DB 4 , TD 4 ) of the second voltage control unit based on said deviation.