A feeder in electrical engineering is a circuit or transmission line together with auxiliary elements, with the help of which electricity flows from a source to a consumer. Moreover, it includes many components. To facilitate orientation in the electrical network, separate sections of it are distinguished and special names are used.
Content
- The concept of the term
- Description of the device
- Trunk and distribution lines
- Protection of equipment in electric vehicles
The concept of the term
This word has a lot of meanings, not all of which are related to the electric power industry. Not every electrician will understand what is meant by the term “feeder”. Here, perhaps, we mean the network that powers the substation transformers and then connects them to a specific breaker.
This applies mainly to electrical lines with a voltage of 6 to 10 kV. In practice, there is such a situation when the general machine is turned off on the transformer device. In this case, the feeder is said to be disconnected. That is, it turns out that in this case the feeder is the line that feeds a certain element of the substation.
It includes:-
high-voltage switching devices; - discharge devices;
- instrument transformers;
- insulators;
- power cable and overhead transmission lines;
- protection devices, etc.
The distribution equipment includes several feeders, which form the following devices: stationary, open, closed, complete for indoor or outdoor installation.
And also in the power industry, these include power lines running from substation to substation or from substation to switchgear. Feeder refers to the trunk lines connecting electrical substations with a distribution unit.
Description of the device
In the design and construction of an electrical main, feeders are cables that connect distribution equipment with consumers or other nodes. Lines that extend from a distribution facility are called branches.
Electric lines can be either open or laid in trenches. In both cases, they perform the same task, namely connect busbars in switchgear with consumer electrical objects.
For example, in traction power supply, the section of the network that connects the voltage buses to the overhead network also refers to feeders. For their safe operation, the equipment is protected by circuit breakers and high-voltage disconnectors.
All structural elements that relate to these areas are called feeder equipment. Thus, the feeder is practically a power line or a separate section of it, supplying electricity to substations or other distribution nodes.
Trunk and distribution lines
If a high voltage is used in the transmission of electricity, then this makes it possible to avoid large losses on high-voltage transmission lines and you can install cables with a smaller cross-section. This especially plays a big role in the transmission of electricity over long distances, since in this case the current strength decreases, which affects the losses.
Electricity with a voltage of 110 kV is transmitted via standard trunk lines. Distribution networks use a voltage of 10 kV., which is obtained at transformer substations, where the main feeder, its cells and protective equipment are located.
The drop line connects the secondary winding of the step-down transformer to the distribution equipment, from where the supply feeder lines depart. Usually, the term “feeder” is not used for further transmission of electricity to consumers.
Protection of equipment in electric vehicles
With a large amount of electricity that passes through an electrical line or its main section, the losses in the network load increase. Therefore, the quality of these sections directly affects the power loss. To protect against overloads, as well as to disconnect the lines, protection schemes using switches are used. There are two types of protection, namely:
-
main; - backup.
The parameters of the circuits directly depend on the operating voltage. Thus, in high voltage traction transformer devices, the circuit breakers contain both forms of protection. This equipment has a fairly high response speed. At the same time, its control is carried out from circuits that provide the functions of current impulse and standard protection.
These types are the main protection against short circuits, and to increase their reliability, they use backup equipment. Feeders in a traction network are the most complex of their types. Since their location is directly related to the contact wires, electric locomotives and electric trains constantly load the circuit, moving along the rails.
At the same time, the load of the networks is directly related to the mass of the rolling stock and the terrain. In addition, the circuit begins to work hard when several electrical sections are turned off for repair or maintenance. The efficiency of the feeder protection is essential for the safe movement of electric trains.
The contact circuit cable is thin and cannot withstand high current loads. A current of 2 kA burns through this wire in an instant, so only high-speed protection can save such a network, which can turn off the feeders in 0.14 seconds.
For this, vacuum or oil machines are installed in the system, which are included in a two-stage protection based on teleblocking and accelerated current cut-off. Structurally, the entire system is made as a separate mechanism.
Recently, instead of the term “feeder”, power engineers use the phrase “outlet line” more and more often. While this fact is not documented, therefore, it is allowed to use both meanings.
