The Basics of Electric Power Transmission

published September 2, 2021
Image of High voltage transformer

From Power Lines to Users

When you turn on a switch in your home or office, you expect the lights to come on. Many people don’t give a lot of thought to the electrical energy that powers all the fittings and how it moves from generating stations into homes and offices all over the country. The electricity transmission and distribution system control the movement of electrical energy from the main power station to a substation where voltage is transformed and directly distributed to consumers.

Transmission Vs. Distribution: What is the difference

Transmission and distribution are two buzz terms that are often used interchangeably in the power management industry. However, These two phrases describe the successive steps of conveying energy from generators to a home or office building via poles and wires. The main difference between the transmission and distribution is the electricity voltage level at each stage.

After power is generated, it is transported from the plant to both homes and businesses via a network of electrical cables. A transmission network is made up of interconnecting lines that allow electrical energy to be moved. These lines can be found both above and below ground. Transmission and distribution are two distinct stages or systems on the grid, but when combined, transmission and distribution lines form the electricity grid.

Power transmission typically happens in two phases:

  • Primary Transmission
  • Secondary Transmission

Primary Transmission

The movement of a substantial amount of electrical power from the initial generating station to the substation through overhead power lines is known as primary transmission.

When electricity is generated at a power plant, the voltage is normally between 11 and 33 kV. Before being delivered through transmission lines to distribution centers, the electrical energy is stepped up to a voltage level of 100kV to 700kV using a transformer. The transmission distance determines the precise step-up voltage. The step-up voltage is usually higher if the electricity is being supplied over a longer distance.

This step-up procedure is necessary to mitigate the I2R losses that occur during power transmission. When the voltage is stepped up, the current drops in relation to the voltage, keeping the power constant and lowering I2R losses.

Secondary Transmission

The voltage is decreased to a level between 33kV and 66kV when electrical power reaches a receiving station. The power is then transported via transmission lines from the receiving station to electrical substations located closer to the endpoint. Electricity is stepped down again at the final substation by a step-down transformer to voltages closer to the initial 11kV.

At this point, the transmission phase transitions to the distribution phase, where electricity is used to meet general and specific consumer demand.

The final step in the supply of electrical power from the source of generation to the end consumer is power distribution. Many people are familiar with distribution lines, which run along streets and connect overhead poles.

The distribution system transports power at a voltage that can be given directly to a home or business. Distribution lines have a voltage of around 13 kV, although a typical residence only runs on about 110 volts.

Infrastructure Solutions with Davis Infrastructure

At Davis Infrastructure, we streamline the entire process of power distribution to mission-critical establishments, from product specs and prompt, accurate quotes, to managing the project through installation and anything that arises afterward.

We’re trusted by our clients as a single point of contact for providing knowledge, equipment sales, and project management that make it faster, easier (and often less expensive) for clients to buy superior power-infrastructure solutions.


Back to the blog