US6411067B1
Expired / Lapsed
US
⏱️ 0.0 years remaining
Voltage source converters operating either as back-to-back stations or as parallel static var compensators
Assignee: Hitachi Energy Ltd
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Filing: 2001-02-20
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Granted: 2002-06-25
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Expires: 2021-02-20
Abstract
Abstract A device and a method for controlling the flow of electric power in a transmission line carrying alternating current, in which a first voltage source converter is connected to the transmission line at a first point and a second voltage source converter is connected to the transmission line at a second point. Further, the first and second voltage source converters have their direct current sides connected to a common capacitor unit. Also included is a by-pass switch connected to the transmission line between the first point and the second point in parallel with the first and second voltage source converters so that the first and second voltage source converters will operate as a back-to-back station when the by-pass switch is open and as two parallel static var compensators when the by-pass switch is closed.
Inventors
- 👤 Hans Björklund
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 05:11
CPC Classifications
H; H02; H02J; H02J3/00; H02J3/18; H02J3/1807; H02J3/1814; H02M; H02M7/00; H02M7/42; H02M7/44; H02M7/48; H02M7/483; H02M7/487; Y; Y02; Y02E; Y02E40/00; Y02E40/10
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
125 words
A device for controlling the flow of electric power in a transmission line carrying alternating current, said device comprising: a first voltage source converter connected to the transmission line at a first point; a second voltage source converter connected to the transmission line at a second point, said first and second voltage source converters having their direct current sides connected to a common capacitor unit; a by-pass switch connected to the transmission line between said first point and said second point in parallel with the first and second voltage source converters so that the first and second voltage source converters will operate as a back-to-back station when the by-pass switch is open and as two parallel static var compensators when the by-pass switch is closed.
Claim 2
Independent Claim
125 words
A device for controlling the flow of electric power in a transmission line carrying alternating current, said device comprising: a first voltage source converter connected to the transmission line at a first point; a second voltage source converter connected to the transmission line at a second point, said first and second voltage source converters having their direct current sides connected to a common capacitor unit; a by-pass switch connected to the transmission line between said first point and said second point in parallel with the first and second voltage source converters so that the first and second voltage source converters will operate as a back-to-back station when the by-pass switch is open and as two parallel static var compensators when the by-pass switch is closed.
Claim 3
Dependent Claim
14 words
A device according to claim 1 , wherein the by-pass switch comprises a breaker.
Claim 4
Dependent Claim
14 words
A device according to claim 1 , wherein the by-pass switch comprises a disconnector.
Claim 5
Dependent Claim
75 words
A device according to claim 1 , wherein each voltage source converter has at least one phase leg having at least two current valves connected in series, said valves including at least one semiconductor element of a turn-off type and at least one rectifying member connected in anti-parallel therewith, and wherein a mid point of the phase leg between said valves forms a phase output and is connected to a phase of the transmission line.
Claim 6
Dependent Claim
22 words
A device according to claim 4 , wherein said semiconductor elements of the turn-off type comprise bipolar transistors having an insulated gate.
Claim 7
Dependent Claim
21 words
A device according to claim 4 , wherein said semiconductor elements of the turn-off type comprise thyristors of a turn-off type.
Claim 8
Dependent Claim
33 words
A device according to claim 4 , wherein each current valve comprises a plurality of semiconductor elements of a turn-off type connected in series and a plurality of rectifying members connected in series.
Claim 9
Dependent Claim
18 words
A device according to claim 1 , wherein each voltage source converter is a six pulse bridge converter.
Claim 10
Dependent Claim
16 words
A device according to claim 1 , wherein each voltage source converter is a three-level converter.
Claim 11
Dependent Claim
57 words
A device according to claim 1 , wherein the voltage source converters are arranged to conduct the current through the device in such a way during a breaking operation of the by-pass switch that essentially no current or only a limited current passes the by-pass switch so as to assist the by-pass switch in said breaking operation.
Claim 12
Independent Claim
124 words
A method for controlling the flow of electric power in a transmission line carrying alternating current, wherein the alternating current alternatively is conducted through a back-to-back station comprising a first voltage source converter, connected to the transmission line at a first point, a second voltage source converter, connected to the transmission line at a second point, and a direct current link capacitor unit connected between said first and second voltage source converters, or through a by-pass switch arranged in the transmission line between said first point and said second point in parallel with the first and second voltage source converters, said first and second voltage source converters operating as two parallel static var compensators when the alternating current is conducted through the by-pass switch.
Claim 13
Independent Claim
124 words
A method for controlling the flow of electric power in a transmission line carrying alternating current, wherein the alternating current alternatively is conducted through a back-to-back station comprising a first voltage source converter, connected to the transmission line at a first point, a second voltage source converter, connected to the transmission line at a second point, and a direct current link capacitor unit connected between said first and second voltage source converters, or through a by-pass switch arranged in the transmission line between said first point and said second point in parallel with the first and second voltage source converters, said first and second voltage source converters operating as two parallel static var compensators when the alternating current is conducted through the by-pass switch.
Claim 14
Dependent Claim
145 words
An alternating current network, comprising: devices for controlling the flow of electric power in the network, each device comprising: a first voltage source converter connected to a transmission line of the network at a first point; and a second voltage source converter connected to said transmission line at a second point, the first and second voltage source converters being connected to a common direct current link capacitor unit; a by-pass switch connected to said transmission line between said first point and said second point in parallel with the first and second voltage source converters so that the first and second voltage source converters will operate as a back-to-back station when the by-pass switch is open and as two parallel static var compensators when the by-pass switch is closed; and control means connected to the voltage source converters and the by-pass switch for controlling each device.
Claim 15
Dependent Claim
145 words
An alternating current network, comprising: devices for controlling the flow of electric power in the network, each device comprising: a first voltage source converter connected to a transmission line of the network at a first point; and a second voltage source converter connected to said transmission line at a second point, the first and second voltage source converters being connected to a common direct current link capacitor unit; a by-pass switch connected to said transmission line between said first point and said second point in parallel with the first and second voltage source converters so that the first and second voltage source converters will operate as a back-to-back station when the by-pass switch is open and as two parallel static var compensators when the by-pass switch is closed; and control means connected to the voltage source converters and the by-pass switch for controlling each device.
Claim 16
Dependent Claim
23 words
An alternating current network according to claim 12 , wherein the control means of several devices are remote-controlled from a common control station.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2005-06-24 | 2005-12-24 | 2006-06-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2009-06-24 | 2009-12-24 | 2010-06-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2013-06-24 | 2013-12-24 | 2014-06-25 | $7700.00 | Window Closed / Lapsed |