US4625254A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Voltage trigger means for a series capacitor protector
Assignee: ABB Norden Holding AB
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Filing: 1984-06-15
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Granted: 1986-11-25
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Expires: 2004-06-15
Abstract
Abstract A linear resistor is serially connected to a voltage-dependent metal oxide varistor and the series-connected resistor elements are connected in parallel with the series capacitor of a high voltage network to provide an overvoltage protection circuit for the series capacitor. A spark gap is also connected in parallel with the series-connected resistor elements in case of overload thereof. The voltage across the linear resistor triggers device for firing the spark gap when the voltage across the linear resistor exceeds a predetermined voltage. The resistance of the linear resistor and that of the varistor is dimensioned such that the predetermined voltage constitutes the smaller part of the voltage across the capacitor.
Inventors
- 👤 Nils Fahlen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 07:44
CPC Classifications
H; H02; H02H; H02H7/00; H02H7/16; H02H9/00; H02H9/04; H02H9/06
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
109 words
A protective circuit for a series capacitor in a high-voltage network, said circuit comprising: a voltage-dependent resistor built up of metal oxide varistors and a linear resistor connected in series therewith, said series-connected voltage-dependent resistor and linear resistor being connected in parallel with a series capacitor; at least one spark gap in parallel with said series-connected voltage-dependent resistor and linear resistor to shunt the latter with overload voltage thereof; a trigger device to trigger said spark gap and responsive to the voltage generated across said linear resistor when said voltage exceeds a predetermined voltage; and said predetermined voltage being less than half the total voltage across said series capacitor.
Claim 2
Dependent Claim
109 words
A protective circuit for a series capacitor in a high-voltage network, said circuit comprising: a voltage-dependent resistor built up of metal oxide varistors and a linear resistor connected in series therewith, said series-connected voltage-dependent resistor and linear resistor being connected in parallel with a series capacitor; at least one spark gap in parallel with said series-connected voltage-dependent resistor and linear resistor to shunt the latter with overload voltage thereof; a trigger device to trigger said spark gap and responsive to the voltage generated across said linear resistor when said voltage exceeds a predetermined voltage; and said predetermined voltage being less than half the total voltage across said series capacitor.
Claim 3
Dependent Claim
53 words
A protective circuit according to claim 7, wherein said trigger device comprises a control circuit with a plurality of series-connected auxiliary spark gaps, and at least one of the auxiliary spark gaps is included in a parallel circuit connected to the linear resistor and has a firing voltage corresponding to said predetermined voltage.
Claim 4
Dependent Claim
29 words
A protective circuit according to claim 2, wherein the voltage-dependent resistor is connected in series with a circuit breaker which is closed during normal operation of the high-voltage network.
Claim 5
Dependent Claim
46 words
A protective circuit according to claim 2, wherein the voltage-dependent resistor functions as a voltage divider for the control circuit, and further comprising a cross-connection from a point between two of the auxiliary spark gaps to a point between two series-connected parts of the voltage-dependent resistor.
Claim 6
Dependent Claim
29 words
A protective circuit according to claim 4, wherein the voltage-dependent resistor is connected in series with a circuit breaker which is closed during normal operation of the high-voltage network.
Claim 7
Dependent Claim
40 words
A protective circuit according to claim 2, wherein the series capacitor is divided into two series-connected capacitors, and further comprising a cross-connection from a point between two of the auxiliary spark gaps to a point between said two series-connected capacitors.
Claim 8
Dependent Claim
29 words
A protective circuit according to claim 6, wherein the voltage-dependent resistor is connected in series with a circuit breaker which is closed during normal operation of the high-voltage network.
Claim 9
Dependent Claim
31 words
A protective circuit according to claim 1, wherein the trigger device comprises a pulse transformer, the low-voltage winding of which is connected via a varistor in parallel across said linear resistor.
Claim 10
Dependent Claim
29 words
A protective circuit according to claim 8, wherein the voltage-dependent resistor is connected in series with a circuit breaker which is closed during normal operation of the high-voltage network.
Claim 11
Dependent Claim
29 words
A protective circuit according to claim 1, wherein the voltage-dependent resistor is connected in series with a circuit breaker which is closed during normal operation of the high-voltage network.
References Cited (Backward Citations)
US2862152A
Cited
US2878428A
Cited
US4174529A
Cited
US4295174A
Cited
US4347539A
Cited
US4432029A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1989-11-24 | 1990-05-26 | 1990-11-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-11-24 | 1994-05-26 | 1994-11-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-11-24 | 1998-05-26 | 1998-11-25 | $7700.00 | Window Closed / Lapsed |