Power-electronic circuit arrangement for compensating for mains system disturbances and mains voltage reductions

• US 6,178,076 B1
• Filed: 04/02/1999
• Issued: 01/23/2001
• Est. Priority Date: 04/02/1998
• Status: Expired due to Fees

• Current Assignee: Asea Brown Boveri AG (ABB Limited)
• Original Assignee: Asea Brown Boveri AG (ABB Limited)
• Inventors: Dähler, Peter, Grüning, Horst
• Primary Examiner(s): Jackson, Stephen W.
• Assistant Examiner(s): RIOS CUEVAS, ROBERTO JOSE
• Application Number:
  US09/285,448
• Time in Patent Office: 662 Days
• Field of Search: 361/21, 361/90, 361/115, 307/43, 307/44, 307/45, 307/64, 307/65, 307/75, 307/80, 307/81, 307/98, 307/99, 307/102, 307/103, 323/205, 323/207
• US Class Current: 361/90
• CPC Class Codes: H02J 3/1814 wherein al least one reactive element is actively controlled by a bridge converter, e.g. unified power flow controllers [UPFC]
• CPC Class Codes: H02J 3/24 Arrangements for preventing or reducing oscillations of power in networks by control effected upon a single generator H02P9/00
• CPC Class Codes: Y02E 40/10 Flexible AC transmission systems [FACTS]

Abstract

In a power-electronic circuit arrangement for compensating for mains system voltage reductions and mains system disturbances, a second auxiliary voltage source is provided, whose voltage is chosen to be less than that of the first auxiliary voltage source. The second auxiliary voltage source can be coupled to the feeder converter with the aid of a switch. The circuit according to the invention can thus operate in two different modes: when the first auxiliary voltage source is coupled to the feeder converter, the available voltage is sufficiently high to compensate for mains system failures or mains system voltage reductions. However, when less severe disturbances occur, the second, lower auxiliary voltage source is coupled to the feeder converter, and mains system disturbances can in consequence be compensated for without any major switching losses. The circuit then operates in a regulated mode, and the switching losses of the semiconductor switches in the feeder converter can be kept at an acceptable level, which is typically less than the losses when switched on. A further option for influencing the voltage is achieved by pulsing, in particular by pulse-width modulation of the switches, in a regulated mode.

Claims

1. A power-electronic circuit arrangement for compensating for mains system disturbances and mains voltage reductions in a voltage supply system comprising:

a) a feeder converter which is connected via a feeder transformer to the voltage supply mains system, is fed from a first auxiliary voltage source with a first auxiliary voltage and which, when mains system disturbances or mains voltage reductions are present, is designed to feed a compensating voltage into the voltage supply mains system; and

b) a filter which can be connected in parallel with the feeder transformer on the mains system side;

wherein

c) at least one secondary auxiliary voltage source is provided, with a second auxiliary voltage which can be coupled to the feeder converter instead of the first auxiliary voltage source, in which case the second auxiliary voltage is chosen to be less than the first auxiliary voltage.

2. The circuit arrangement as claimed in claim 1, wherein the feeder converter is pulse-width-modulated during mains system disturbances.