| 摘要 |
<p>A 3-phase overhead distribution network operates at intermediate voltage (e.g. 11 kV to 33 kV), between a high voltage supply network (at e.g. 110 kV or 275 kV) and a consumer mains system (at e.g. 110 V or 230 V). A signalling system uses signals at frequencies preferably in the region of 10 kHz to 100 kHz for signalling over the network, the signals being coupled inductively to and from the network. The signals are coupled to different phases at different points in the network cross-coupling between the phases ensures that signals coupled onto the system on one phase give adequate signal strength for detection at other points in the system regardless of which phase the detector is coupled to.</p> |
