There are two general sides of the business that you can focus on once you get started as a lineman, transmission or distribution.
Transmission is the higher voltage system that carries electricity from generators (plants) to distribution centers.
Distribution is the lower voltage system that carries the electricity from distribution to customers. These are the lines that you see on the side of the road.
Full System
Power is generated typically at the generating stations or power plants. The transmission lines then carry the electricity to an electrical substation or large industrial transmission side customers. The electric then is carried to transformers that step down the voltage for the customer. As shown below:
Transmission
- Higher Voltage. Transmission operates between 69 kV and 765 kV. The lines are higher than distribution lines, and the cables are thicker.
- Bi-directional. To balance the grid, it is necessary that the current be allowed to flow in either direction.
- Maintenance. Transmission networks are actively tracked and require more preventative maintenance.
Distribution
- Lower Voltage. Distribution operates between 4KV and 69KV to a secondary transformer then to 120V or 240V.
- Mono-directional. Distribution lines were designed to transmit power in only one direction. In recent years this had become more problematic due to small generation facilities (like wind and solar installations) joining on the distribution side.
- Maintenance. Distribution systems are passive. They typically require less preventative but more emergency maintenance.