Patent ID: 11942790
Assignee: GENERAL ELECTRIC TECHNOLOGY GMBH
Field: Electrical machinery, apparatus, energy (Electrical engineering)
Classification: CPC H  Y | IPC H

Claim 0:
1. A control apparatus for controlling a frequency set-point for a first AC network electrically connected to a first HVDC station to regulate active power, the controller comprising:
a frequency controller operable in a first mode of operation to determine a frequency set-point (FRef) for the first AC network based on a measured value of DC voltage (VDC1) at the first HVDC station; and
a disturbance detector configured to monitor the measured value of DC voltage at the first HVDC station (VDC1) for a predetermined characteristic indicative that a variation in measured DC voltage corresponds to a known modulation applied to the DC voltage by a second HVDC station;
wherein, in the first mode of operation, the frequency controller is configured to determine the frequency set-point (FRef) for the first AC network based at least in part on the measured value of DC voltage (VDC1) if the predetermined characteristic is detected, and to control the frequency set-point (FRef) for the first AC network to a predetermined default frequency if said predetermined characteristic is not detected; and
wherein the disturbance detector is configured to compare a first value based on the present measured value of DC voltage (VDC1) to a second value (VDC_EST) based on the value of the frequency set-point (FRef) for the first AC network and said predetermined characteristic is that the first and second values differ by less than a defined amount (DIFF).