VOLTAGE SOURCE CONVERTER FOR HIGH VOLTAGE DIRECT CURRENT POWER TRANSMISSION

• US 20100309698A1
• Filed: 09/05/2007
• Published: 12/09/2010
• Est. Priority Date: 09/05/2007
• Status: Active Grant

• Current Assignee: ABB Power Grids Switzerland AG (ABB Limited)
• Original Assignee: ABB Technology AG (ABB Limited)
• Inventors: Asplund, Gunnar, Juhlin, Lars-Erik
• Granted Patent: US 8,345,457 B2
• Time in Patent Office: Days
• US Class Current: 363/126
• CPC Class Codes: H02J 3/36 Arrangements for transfer of electric power between ac networks via a high-tension dc link
• CPC Class Codes: H02M 7/05 Capacitor coupled rectifiers
• CPC Class Codes: H02M 7/797 using semiconductor devices only
• CPC Class Codes: Y02E 60/60 Arrangements for transfer of electric power between AC networks or generators via a high voltage DC link [HVCD]

Abstract

A high voltage AC/DC or DC/AC power conversion system including a voltage source converter with at least two series-connected converter valve bridges, at least two reactors, where each of the reactors is connected to one of the AC phase terminals of the at least two bridges and at least one transformer connected to an AC supply voltage. In order to block a DC voltage from the at least one transformer, one of at least two capacitors is connected in series with each of the at least two reactors and is connected between the corresponding reactor and the at least one transformer.

Claims

1. High voltage AC/DC or DC/AC power conversion system comprising

a voltage source converter with at least two series-connected converter valve bridges (31),

at least two reactors (33), where each of the reactors (33) is connected to one of the AC phase terminals (32) of the at least two bridges (31),

characterized in that the system further comprises

at least two capacitors (34), where each capacitor (34) is connected in series with one of the at least two reactors (33).

2. System according to claim 1, where at least one transformer (45;

36;

39) is connected to an AC supply voltage (44) and where each of the at least two capacitors (34) is connected between the corresponding reactor (33) and the at least one transformer (45;

36;

39).

3. System according to claim 1 or 2, where at least one harmonic filter (35) is shunt-connected to the transformer (45;

36;

39).

4. System according to claim 3, where at least two of the series connections of reactor (33) and capacitor (34) are connected in parallel with each other and where their common connection point (40;

41;

42) is connected to one transformer (36;

39) and one harmonic filter (35).

5. System according to claim 4, where the common connection point (40;

41;

42) is connected via an additional reactor (38) to the one transformer (36;

39) and the one harmonic filter (35).

6. System according to any of claims 1 to 5, where the at least one transformer is a two winding transformer (45;

36).

7. System according to claim 4 or 5, where the system comprises at least four series-connected converter valve bridges (31) and at least four series connections of reactor (33) and capacitor (34) which are parallel connected in two groups and where the at least one transformer is a three-winding transformer (39) with each of two secondary windings being connected to the common connection point (42) of one of the two groups or where a two-winding transformer is connected to each one of the two groups.

8. System according to any of claims 1 to 7, where a surge arrester (43) is connected across each of the capacitors (34).