Voltage Source Converter Station

• US 20100008111A1
• Filed: 08/25/2006
• Published: 01/14/2010
• Est. Priority Date: 08/25/2006
• Status: Active Grant

• Current Assignee: ABB Power Grids Switzerland AG (Hitachi, Ltd.)
• Original Assignee: ABB Technology Limited (ABB Limited)
• Inventors: Jiang, Lin, Petersson, Anders
• Granted Patent: US 8,144,488 B2
• Time in Patent Office: Days
• US Class Current: 363/41
• CPC Class Codes: H02J 2003/365 Reducing harmonics or oscillations in HVDC
• 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 1/126 using passive filters
• 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

The resistors of a filter block in a voltage source converter station are connected with a floating neutral point.

Claims

1. A converter station comprising:

a voltage source converter (VSC1) coupled between a direct current link (W1, W2) and an alternating current network (N1) in a high voltage direct current transmission system; and

a filter block (F1) coupled between the voltage source converter and the alternating current network for filtering current harmonics in the alternating current network;

characterized in that

the resistive part of the second filter block (F1) comprises a common ungrounded electrical zero between phases.

2. The converter station according to claim 1, wherein the voltage source converter (VSC1) is a pulse width modulated converter.

3. The converter station according to claim 1, wherein the filter block (F1) is coupled at a connection point between a phase inductor (PI1) and a transformer (T1) connecting to the three-phase network (N1).

4. The converter station according to any of claims 1-3, wherein the filter block (F1) is a tuned filter with band pass characteristics for harmonics that constitute zero sequence harmonics and a damped filter with high pass characteristics for harmonics that constitute positive or negative sequence harmonics.

5. The converter station according to any of claims 1-4, wherein the filter block (F1) of each phase comprises:

a capacitor (C) and an inductor (L) serially connected between a phase line (L1) and ground, wherein the capacitor is connected to the phase line and the inductor to ground, and

a resistor (R) that in one end is connected to the junction point between the capacitor (C) and the inductor (L) and in the other end is connected to a floating neutral point.

6. The converter station according to claim 5, wherein the filter block (F1) comprises a second inductor (L′

) and a second capacitor (C′

) connected in parallel with each other and in series with the capacitor (C).

7. The converter station according to claim 6, wherein the filter block (F1) comprises a third inductor (L″

) and a third capacitor (C″

) connected in parallel with each other and in series with the capacitor (C).

8. The converter station according to any of claims 1-7, comprising a second filter block (F2) connected in parallel with the filter (F1), wherein the second filter block is ungrounded.