Overhead transmission lines are the main components of power systems and transmission networks. It undertakes most of the transmission tasks in industry and life, and it is also the most prone part of the power system.
Common faults are classified by nature, and are mainly divided into transient faults and permanent faults.
Among them, transient faults mainly include flashover caused by lightning overvoltage and short circuit caused by birds. Permanent faults are mostly caused by weather or the equipment itself: such as transient over-voltage breakdown caused by icy weather or line aging, transmission line insulation, equipment installation, storms, earthquakes and other transmission lines are permanently short-circuited and quickly.
1. The Characteristics Of Bird Hazards
Birds often land on overhead power lines to rest, but they are also harmful to transmission lines. The damage is mainly caused by arcing caused by nesting, flying and bird droppings. Birds nesting on transmission lines are mostly branches, and branches have little effect on the line in dry weather. But in the event of rainy weather, the bird's nest is easily blown over the wires or insulators by the wind. It is easy to cause grounding short-circuit of overhead transmission lines, and circuit accidents may cause serious ground wire burns and other accidents.
2. Thunderstorms From Travel
Thunderstorms attacking overhead transmission lines can easily cause overvoltage in the lines. This overvoltage is also called external overvoltage because it originates from the external power system. Usually divided into two kinds of induced overvoltage and DC overvoltage. Voltage easily causes flashover and tripping in the line. The lightning flashover discharge is mainly caused by tripping, which will cause obvious discharge traces on the surface of the transmission line insulator.
3. Characteristics Of Icing Faults On Transmission Lines
The icing of the line is mainly due to heavy snow or stormy weather, as well as the influence of temperature and humidity. This phenomenon of large changes in air is easy to adhere to the surface on icy lines. The icing will gradually thicken as it cools. Once an ice layer is formed, it will cause transmission line overload and insulator ice flash, resulting in tower deformation, tower or insulator damage, flashover and other faults. The load is mainly generated by the weight, weight and wind of the line itself. In some cases, the transmission line will have a greater diagnostic amplitude and frequency, that is, speeding, which will directly affect the safe and reliable operation of the transmission line.
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