MEANS FOR GENERATING REACTIVE POWER

• US 3,829,759 A
• Filed: 01/18/1973
• Issued: 08/13/1974
• Est. Priority Date: 01/18/1973
• Status: Expired due to Term

• Current Assignee: Kjeld Thorborg
• Original Assignee: Kjeld Thorborg
• Inventors: Thorborg, Kjeld
• Primary Examiner(s): Beha, Jr., William H.
• Application Number:
  US05/218,844
• Time in Patent Office: 572 Days
• Field of Search: 323/101,102,105,106,119,127 321/9,27R
• US Class Current: 323/207
• CPC Class Codes: H02J 3/185 wherein such reactive element is purely inductive, e.g. superconductive magnetic energy storage systems [SMES]
• CPC Class Codes: H02M 7/515 using semiconductor devices only
• CPC Class Codes: Y02E 40/20 Active power filtering [APF]

Abstract

An arrangement for generating reactive power includes first and second line-commutated converters, the AC terminals of which are connected to an alternating voltage network to which a capacitor bank is also connected. Two branchless connections connect the converters in anti-parallel relation on the DC side and constitute an unloaded DC intermediate line, each DC terminal of each converter being connected by a branchless reactor connection to a DC terminal of the other converter.

Claims

1. Means for generating reactive power, which comprises a first and a second line-commutated converter, each with AC terminals for connection to an alternating voltage network, a capacitor bank for connection to said network, two branchless reactor connections anti-parallel connecting the converters on the DC side and constituting an unloaded DC intermediate line, each DC terminal of each converter being connected by a branchless reactor connection to a DC terminal of the other converter.

2. Means according to claim 1, which comprises control pulse devices arranged to emit firing pulses to the rectifiers in the two converters in such a way that each rectifier in the second converter is fired with a certain delay in relation to the firing of the corresponding rectifier in the first converter, said delay being substantially equal for all the rectifiers of the second converter.

3. Means according to claim 2, in which sensing members are arranged to sense a magnitude corresponding to the total reactive power generated by both converters and to influence said control pulse devices to influence the firing times of the rectifiers in accordance with the deviation of said power from a desireD value.

4. Means according to claim 2, in which said delay has a contant value.

5. Means according to claim 4, in which the delay has a value corresponding to an electric angle of between 20* and 40*.

6. Means according to claim 2, in which said delay is variable.

7. Means according to claim 2, in which the sensing members are voltage sensing members including means to sense the voltage at a point in the AC network and to influence said control devices to affect the firing times of the rectifiers, in dependence upon the deviation between said voltage and a desired value.

8. Means according to claim 2, in which said control pulse devices include means to control the rectifiers of a converter so that each group of rectifiers connected to the same phase-conductor is fired with substantially the same control angle.

9. Means according to claim 8, in which said sensing members are voltage sensitive members for sensing the asymmetry in the alternating voltage at a point in the alternating voltage network and, dependent on the magnitude of the asymmetry, to influence the control angles for said groups.