DC voltage compensation in a multi-terminal HVDC power transmission network
AssigneeABB Technology AG
InventorLars-Erik Juhlin
Life of this patent
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Abstract
In a multi-terminal HVDC power transmission network comprising at least three HVDC converter stations interconnected by at least two transmission lines, where at least one of the transmission lines is a long line, an active voltage source device is series connected to one of the transmission lines, which maintains the DC voltage of the transmission lines of the network to be within a predefined voltage range by injecting an additional DC voltage in series with the one transmission line.
Claims26
A method to control a multi-terminal HVDC power transmission network comprising at least two transmission lines, wherein at least one of the transmission lines has a length of approximately or more than 500 km, wherein the DC voltage level of the transmission lines is maintained to be within a predefined voltage range by controlling an active voltage source device which is connected in series to one of the transmission lines to inject a DC voltage in series with the one of the transmission lines, wherein the active voltage source device is arranged to be power supplied from the one of the transmission lines and comprises a first converter in series connection with the one of the transmission lines and a second converter in shunt connection with the one of the transmission lines, the method comprising the steps of:
- converting, by the second converter working as an inverter, DC power from the one of the transmission lines into AC power,
- supplying, by said second converter, the first converter with said AC power, and
- providing, by the first converter working as a rectifier, the DC voltage to be injected into the one of the transmission lines.
A multi-terminal HVDC power transmission network comprising at least three HVDC converter stations interconnected by at least two transmission lines, wherein at least one of the transmission lines is a line having a length of approximately or more than 500 km, and an active voltage source device is connected in series to the one of the transmission lines and configured to maintain the DC voltage of the transmission lines of the network to be within a predefined voltage range by injecting a DC voltage in series with the one of the transmission lines and arranged to be power supplied from the one of the transmission lines,
- wherein the active voltage source device comprises a first converter in series connection with the one of the transmission lines and a second converter in shunt connection with the one of the transmission lines, the second converter works as an inverter to convert DC power from the one of the transmission lines into AC power to supply the first converter with said AC power, and the first converter works as a rectifier to provide the DC voltage to be injected into the one of the transmission lines.
An active voltage source device arranged to be connected in series with one of at least two transmission lines of a multi-terminal HVDC power transmission network, to maintain the DC voltage of the transmission lines in the network to be within a predefined voltage range by injecting a DC voltage in series with the one of the transmission lines and to be power supplied from the one of the transmission lines,
- wherein the active voltage source device comprises a first converter in series connection with the one of the transmission lines and a second converter in shunt connection with the one of the transmission lines, the second converter works as an inverter to convert DC power from the one of the transmission lines into AC power to supply the first converter with said AC power, and the first converter works as a rectifier to provide the DC voltage to be injected into the one of the transmission lines.
Dependencies are inferred from the claim text.