×

Converter for HVDC transmission and reactive power compensation

  • US 9,490,693 B2
  • Filed: 04/13/2015
  • Issued: 11/08/2016
  • Est. Priority Date: 06/18/2010
  • Status: Expired due to Fees
First Claim
Patent Images

1. A power electronic converter for use in high voltage direct current power transmission and reactive power compensation comprising a plurality of switching elements interconnecting in use a DC network and one or more AC networks, the plurality of switching elements being controlled in use to form one or more short circuits within the power electronic converter so as to define one or more primary current flow path including a respective one of the AC networks and the power electronic converter and bypassing the DC network, said power electronic converter further including a plurality of converter limbs, each converter limb including first and second DC terminals for connection in use to the DC network and an AC terminal for connection in use to an AC network, each converter limb defining first and second limb portions, each limb portion including an electronic block connected in series between a respective one of the first and second DC terminals and the respective AC terminal, each electronic block including at least one switching element, the or each switching element of each electronic block being controllable in use to switch the respective limb portion in and out of circuit to facilitate the AC to DC power conversion process, each electronic block including at least one primary switching element, the or each primary switching element being connected in series between the respective one of the first and second DC terminals and the respective AC terminal, each electronic block further including at least one chain-link converter and at least one primary switching element connected in series with the or each chain-link converter, wherein the or each chain-link converter includes a chain of modules connected in series, each module including at least one pair of secondary switching elements connected in parallel with an energy storage device,wherein the secondary switching elements are controlled in use such that the chain of modules connected in series provides a stepped variable voltage source,wherein, in the event of a fault in the DC network resulting in high fault current in the power electronic converter, the secondary switching elements of each module are controlled so that the chain-link converters of the first and/or second limb portions concurrently provide zero voltage, andwherein, after the fault in the DC network has been isolated and repaired, the secondary switching elements of each module are controlled so that the chain-link converters of the first and/or second limb portions switch from concurrently providing zero voltage to concurrently providing positive voltage so as to offset the voltage difference between the respective DC and AC terminals.

View all claims
  • 1 Assignment
Timeline View
Assignment View
    ×
    ×