| 摘要 |
1449682 Line protective systems WESTINGHOUSE ELECTRIC CORP 28 Sept 1973 [4 Oct 1972] 45430/73 Heading H2K A protection system for a polyphase transmission line has at each end of the line current sensing means 13, 14, 15 each associated with relaying networks 20, 21, 22, controlling breaker tripping networks 24 and responsive to overcurrent or discontinuity in an A.C. wave. In Fig. 2 there are four relaying networks 20, 21, 22 or 23; the latter being responsive to ground faults and having its switch SW1 connected to overcurrent detector I L instead of discontinuity detector 58 via the time delay circuit 58A. Under healthy conditions the transmitter-receiver 78 sends a guard signal to the remote end of the line and itself receives a guard signal which enables it to provide signals to a comparison determinator 56, channel supervisor 106 and channel failure unblock circuit 140 which are changed under fault conditions. The other Figures (not shown) give circuit details as set out in Fig. 2. |
