Protective relay with selective phase selection for double lines
US4864453A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 19, 1988 |
| Grant date | Sep 5, 1989 |
| Priority date | — |
| Expiry date | Dec 19, 2008 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02H7/267
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
The invention comprises a protective relay with selective phase selection in electric power distribution systems when there are double transmission lines (M1-P1,M2-P2) between two stations (TM, TP) and where the ends of the line are connected to a common busbar system located in each station. The protective device includes a protection unit, terminal, at both ends of each line. All the terminals (M1, M2, P1, P2) include an identical basic design for measurement of phase quantities (17), filtering (18) and A/D conversion (19); furthermore, the identical part includes a parameter estimator (20) for Fourier series expansion of measured phase signals and generation of the respective residuals. The parameter estimator cooperates with a frequency estimator (21) and a sampling regulator (22). Each basic design also includes a local logic unit which, by transient and steady state analysis, finds out whether an event on the network is due to a fault or a connection/disconnection of the phase/line and the current direction at each terminal. At one of the terminals, at both stations, there is a station master unit (26) which compiles all information for the station in question, calculates the…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.