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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.
Many faults in overhead power lines are transient in nature. When a fault occurs, equipment used for power system protection operate to isolate the area of the fault. A transient fault will then clear and the power-line can be returned to service. Typical examples of transient faults include: momentary tree contact; bird or other animal contact
Markers are often installed on overhead lines near airfields, or at river crossings where there is a possibility of float-equipped aircraft using the river. Some markers contain conductor marking lights or strobe lights to improve visibility at night or in fog. An overhead line obstruction warning marker near an airstrip.
Direct measurement methods use devices that are directly coupled to the line. These devices measure temperature, tension, sag and/or clearance from which the thermal rating is determined. Indirect measurement methods use weather stations and modeling.
An overhead line or overhead wire is an electrical cable that is used to transmit electrical energy to electric locomotives, electric multiple units, trolleybuses or trams. The generic term used by the International Union of Railways for the technology is overhead line . [ 1 ]
Buchholz relays have a test port to allow the accumulated gas to be withdrawn for testing.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.
Fault detection, isolation, and recovery (FDIR) is a subfield of control engineering which concerns itself with monitoring a system, identifying when a fault has occurred, and pinpointing the type of fault and its location. Two approaches can be distinguished: A direct pattern recognition of sensor readings that indicate a fault and an analysis ...
The conventionally used aid in cable fault testing and location is the cable test van. The van is installed with conventional cable measuring systems for quickly reaching the location of any cable fault. In 20 years that followed, over 2000 fault location vehicles were manufactured, more than half of which were intended for the former USSR.