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In such cases the user should consider the downstream capacitive discharge current to avoid false operation of the non-directional indicators. Some overhead line fault indicators called as pole mounted fault indicators can detect the live line and the fault current from 3 to 5 metres (9.8 to 16.4 ft) below the conductors.
line-to-ground fault - a short circuit between one line and ground, very often caused by physical contact, for example due to lightning or other storm damage. In transmission line faults, roughly 65% - 70% are asymmetric line-to-ground faults. [2] double line-to-ground fault - two lines come into contact with the ground (and each other), also ...
Residential customers in areas fed by affected overhead power lines can occasionally see the effects of an autorecloser in action. If the fault affects the customer's own distribution circuit, they may see one or several brief, complete outages followed by either normal operation (as the autorecloser succeeds in restoring power after a ...
Buchholz relays have a test port to allow the accumulated gas to be withdrawn for testing. Flammable gas found in the relay indicates some internal fault such as overheating or arcing, whereas air found in the relay may only indicate low oil level or a leak. [3] Through a connected gas sampling device the control can also be made from the ground.
In the area surrounding the overhead lines it is dangerous to risk interference; e.g. flying kites or balloons, using ladders or operating machinery. Overhead distribution and transmission lines near airfields are often marked on maps, and the lines themselves marked with conspicuous plastic reflectors, to warn pilots of the presence of conductors.
The generic term used by the International Union of Railways for the technology is overhead line. [1] It is known variously as overhead catenary, overhead contact line (OCL), overhead contact system (OCS), overhead equipment (OHE), overhead line equipment (OLE or OHLE), overhead lines (OHL), overhead wiring (OHW), traction wire, and trolley wire.
An arc-fault circuit interrupter (AFCI) or arc-fault detection device (AFDD) [1] is a circuit breaker that breaks the circuit when it detects the electric arcs that are a signature of loose connections in home wiring. Loose connections, which can develop over time, can sometimes become hot enough to ignite house fires.
One drawback of AIS is the visual impact of a larger substation with overhead power lines entering and exiting, which may be unacceptable in scenic or urban areas. [38] AIS requires additional bracing in a seismically active area, and emits more electromagnetic fields and noise than alternative technologies.