EP0442455A2
Expired / Lapsed
EP
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Series capacitor equipment
Assignee: ABB AB
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Filing: 1991-02-13
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Granted: —
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Expires: 2011-02-13
Abstract
Abstract A series capacitor equipment for connection into an electric power line (A) has a capacitor bank (C) and a controllable inductor connection (L, T1, T2) connected in parallel therewith and comprising a series connection of an inductor (L) and a controllable semiconductor connection (T1, T2). Further, the equipment comprises control members (CU) adapted, on the occurrence of a subsynchronous resonance oscillation, to control the semiconductor connection with separate control angle values during positive and negative half-cycles of the capacitor voltage for generation of a subharmonic voltage over the capacitor which counteracts the resonance oscillation.
Inventors
- 👤 Bertil Klerfors
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-29 09:12
CPC Classifications
H; H02; H02J; H02J3/00; H02J3/001; H02J3/0014
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
130 words
Series capacitor equipment with a capacitor bank (C) adapted for connection in series into an electric power line (A) and with a controllable circuit (L, T1, T2), connected to the capacitor bank, for damping subsynchronous resonance oscillations, characterized in that the controllable circuit (L, T1, T2) is connected in parallel with the capacitor bank and includes inductor means, controllable in both directions and comprising at least one inductive component (L) and a controllable semiconductor valve (T1, T2) connected to said component (L), and that the equipment further comprises control members (CU) adapted, on the occurrence of a subsynchronous resonance oscillation, to control said semiconductor valves (T1, T2) with such control angle values that a subharmonic voltage is generated across the capacitor bank, which subharmonic voltage counteracts the subsynchronous resonance oscillation.
Claim 2
Dependent Claim
65 words
Series capacitor equipment according to claim 1, characterized in that the inductive component (L) has an inductance value which is so chosen in relation to the capacitance of the series capacitor bank (C) that the oscillation circuit formed by the inductive component and the capacitor bank has a natural frequency which is at least five times greater than the system frequency of the power line.
Claim 3
Dependent Claim
30 words
Series capacitor equipment according to claim 1 or 2, characterized in that the controllable circuit has an inductor (L) connected in series with a bidirectional controllable semiconductor valve (T1, T2).
Claim 4
Dependent Claim
20 words
Series capacitor equipment according to claim 3, characterized in that the semiconductor valve comprises two antiparallel-connected thyristor valves (T1, T2).
Claim 5
Dependent Claim
64 words
Series capacitor equipment according to claim 1 or 2, characterized in that the controllable circuit (L, T1, T2) comprises two inductors (L1, L2), each connected in series with a semiconductor valve (T1, T2), said semiconductor valve being connected oppositely in relation to each other, and that these two series connections of an inductor and a semiconductor valve are connected in parallel with each other.
Claim 6
Dependent Claim
48 words
Series capacitor equipment according to any of claims 1 to 5, characterized in that the inductor means and/or and the semiconductor valves are connected to the capacitor bank (C) via a transformer (TR), whereby the inductor means may consist merely of the stray reactance of the transformer (TR).
Claim 7
Dependent Claim
74 words
Series capacitor equipment according to any of the preceding claims, characterized in that the control members are adapted, on the occurrence of a subsynchronous resonance oscillation, to control the semiconductor valves with different control angle values relative to the total capacitor voltage (U c ) during the two half-cycles of at least certain pairs of consecutive half-cycles of the capacitor voltage (U c ) for generation of the subharmonic voltage counteracting the resonance voltage.
Claim 8
Dependent Claim
39 words
Series capacitor equipment according to any of the preceding claims, characterized in that it comprises control members (CU) adapted to make the controllable semiconductor valves conductive at the zero crossings of the fundamental frequency component of the capacitor voltage.
Claim 9
Dependent Claim
44 words
Series capacitor equipment according to any of claims 1 to 7, characterized in that it comprises control members adapted to control the controllable semiconductor valves with a variable control angle (β) relative to the fundamental frequency component (U co ) of the capacitor voltage.
Claim 10
Dependent Claim
67 words
Series capacitor equipment according to claim 9, characterized in that the control members are adapted to form a signal (U x ) corresponding to a subharmonic oscillation in the capacitor voltage and, at each firing of a controllable semiconductor valve, to determine the control angle relative to the fundamental frequency component (U co ) of the capacitor voltage in dependence on the current value of said signal.
References Cited (Backward Citations)
No citation records indexed.
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