US3628124A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Variable overvoltage protection means for dc networks
Assignee: ABB Norden Holding AB
•
Filing: 1970-10-09
•
Granted: 1971-12-14
•
Expires: 1990-10-09
Abstract
Abstract An overvoltage protection device for a DC transmission line connecting two stations, each station including several seriesconnected converters each provided with a bypass member, has a series of lightning arrester units connected between the transmission line and earth. At least all but one of the lightning arresters has a bypass device. Relays for closing the bypass devices to short circuit the lightning arresters are connected to the bypass members for the converters in such a way that the number of bypassed lightning arresters corresponds to the number of bypassed converters.
Inventors
- 👤 Arne Johansson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 10:23
CPC Classifications
H; H02; H02H; H02H9/00; H02H9/04; H02H9/06
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
145 words
Overvoltage protection means for a DC transmission line connecting two converter stations, each of which comprises a plurality of series-connected converters each provided with a bypass member, a DC reactor connecting the DC transmission line to each station, the overvoltage protection means in each station comprising a plurality of series-connected lightning arrester units connected outside the DC reactor between the DC transmission line and earth, the protection level of the overvoltage protection means corresponding to the voltage strength of the stations, bypass means connected with at least some of the arrester units, means responsive to operation of the bypass members of the converters to control said bypass means to keep the number of series-connected, active arrester units proportional to the number of series-connected converters, whereby the relationship between the protection level and the voltage strength is substantially independent of the number of converters in operation.
Claim 2
Dependent Claim
145 words
Overvoltage protection means for a DC transmission line connecting two converter stations, each of which comprises a plurality of series-connected converters each provided with a bypass member, a DC reactor connecting the DC transmission line to each station, the overvoltage protection means in each station comprising a plurality of series-connected lightning arrester units connected outside the DC reactor between the DC transmission line and earth, the protection level of the overvoltage protection means corresponding to the voltage strength of the stations, bypass means connected with at least some of the arrester units, means responsive to operation of the bypass members of the converters to control said bypass means to keep the number of series-connected, active arrester units proportional to the number of series-connected converters, whereby the relationship between the protection level and the voltage strength is substantially independent of the number of converters in operation.
Claim 3
Dependent Claim
32 words
Overvoltage protection means according to claim 1, in which each lightning arrester unit is provided with a bypass means controlled by a corresponding bypass member for a converter in the same station.
Claim 4
Dependent Claim
50 words
Overvoltage protection means according to claim 1, in which each lightning arrester unit except one is provided with a bypass means, and said control means comprises a common control device for all arrester units in the station which operates in response to the number of converters connected in the station.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-12-13 | 1975-06-14 | 1975-12-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-12-13 | 1979-06-14 | 1979-12-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-12-13 | 1983-06-14 | 1983-12-14 | $7700.00 | Window Closed / Lapsed |