Elimination of commutation failure by hybrid hvdc system
AssigneeThe University of Birmingham
InventorsXiao-Ping Zhang, Ying Xue
Life of this patent
Estimating the term…
Abstract
A line commutated converter, LCC, for a high-voltage, direct current, HVDC, power converter comprises at least one bridge circuit for connection to at least one terminal of a DC system. Each bridge circuit comprises a plurality of arms, and each arm is associated with a respective phase of an AC system. Each arm comprises an upper and lower thyristor connected in series, an associated branch extending from between the upper and lower thyristors, and at least one capacitor module for each phase. The, or each capacitor module is operable to insert a capacitor into the respective arm of the bridge circuit.
Claims37
A line commutated converter, LCC, for a high-voltage, direct current, HVDC, power converter, the LCC comprising at least one bridge circuit for connection to at least one terminal of a DC system, each bridge circuit comprising a plurality of arms, each associated with a respective phase of an AC system, each arm comprising:
- an upper and lower thyristor connected in series;
- an associated branch extending from between the upper and lower thyristors;
- and
- at least one capacitor module for each phase, the or each capacitor module operable to insert a capacitor into the respective arm of the bridge circuit.
(canceled)
(canceled)
(canceled)
(canceled)
(canceled)
(canceled)
(canceled)
(canceled)
(canceled)
A method of operating a line commutated converter, LCC, for a high-voltage, direct current, HVDC, converter, wherein the LCC comprises at least one bridge circuit for connection to at least one terminal of a DC system, each bridge circuit comprising a plurality of arms, each associated with a respective phase of an AC system, each arm comprising:
- an upper and lower thyristor connected in series;
- an associated branch extending from between the upper and lower thyristors;
- and
- at least one capacitor module for each phase, the method comprising:
- inserting, by the or each capacitor module, a capacitor into the respective arm of the bridge circuit.
(canceled)
A line commutated converter, LCC, for a high-voltage, direct current, HVDC, power converter, the LCC configured as a rectifier for converting from AC to DC, and as an inverter for converting from DC to AC and comprising at least one bridge circuit for connection to at least one terminal of a DC system, each bridge circuit comprising a plurality of arms, each associated with a respective phase of an AC system, each arm comprising:
- an upper and lower thyristor connected in series;
- an associated branch extending from between the upper and lower thyristors;
- and
- at least one capacitor module for each phase, the or each capacitor module operable to insert a capacitor into the respective arm of the bridge circuit,
- wherein the capacitor modules are operable to insert a capacitor into the bridge circuit during a commutation period, wherein commutation is provided from an initially conducting thyristor in an initially conducting arm to a subsequently conducting thyristor in a subsequently conducting arm, to increase an effective commutation voltage, and
- wherein during a fault of the AC system, the effective commutation voltage is controlled to provide a controllable reactive power support to the AC system, whereby the rectifier and inverter, respectively, supply a positive reactive power to the AC system, with a negative firing angle control for the rectifier and a negative extinction angle control for the inverter.
Dependencies are inferred from the claim text.