Directional comparison blocking system
CA 1281407 C · Owner: Li, Hung Jen · Inventors: Mcfall, John Daniel; Li, Hung Jen
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
An echo-keyed directional comparison blocking system for protecting an electrical power transmission path in a power system network against internal faults is disclosed. The system includes a terminal unit disposed at each end of the transmission path for measuring characteristics representative of the power at its corresponding end and for activating a corresponding circuit breaker when an internal fault of the transmission path is detected. Each terminal unit includes a transmitter and a receiver for communicating transmit and receive signals with each other through a communication medium and additionally includes at least one forward-looking pilot relay, at least one overcurrent relay, …
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Listed from its CIPO record in Patent Yard's archive of Canadian patents past their term. Its claims, description and drawings are in the CIPO record and on Google Patents, and the Claude kit works from them.
Why it's free to use
- Granted March 12, 1991. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended March 12, 2008.
- We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
Timeline
Timeline From CIPO dates
Sources & verification
Official CIPO records
Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.