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Transmission and Distribution

This four-minute video shows how electricity gets to your home (source:

Electricity travels at the speed of light - about 671 million miles per hour! A large network of wires conducts electricity from its source to your home. Traveling the large distances from the power plant to substations requires high-voltage transmission lines. From a substation to your neighborhood, electricity is moved across low-voltage distribution lines.

Transmission System

What do transmission lines do?

The purpose of the transmission system is to provide an efficient means of transporting bulk power to substations all across the state.

What is the electrical voltage for transmission lines?

Typical transmission levels range from 69 kV all the way up to 345 kV. This high-voltage level makes the transport of energy more efficient.

How many miles are covered?

Westar Energy operates and maintains about 4,600 miles of transmission lines.

Distribution System

What do distribution lines do?

The distribution system is used to transport power locally from the substations to individual customers.

What is the electrical voltage for distribution lines?

Typical distribution levels range from 2.4 kV to 34.5 kV. This low-voltage level makes the transport of energy safer for neighborhoods.

Why are distribution lines so much smaller than transmission lines?

High-voltage transmission requires larger equipment. That's not a problem outside the city. Low-voltage distribution makes use of smaller equipment that is more suited for neighborhood environments.

Routing power into your home

Why do distribution lines have transformers?

Distribution lines carry electricity at lower voltages, but it's still too powerful to use in your home. So transformers step the energy down to 120 volts for use in lighting and standard home electrical outlets.

How do these transformers work?

The transformer consists of two coils of wire wrapped around a core. All of that is contained within an oil-filled tank. When electricity flows through the primary coils, it creates a magnetic field that induces voltage across the secondary coils.

How many turns does it take to transform the power into usable electricity?

To convert 7,200 volts, there are 60 turns or loops in the coil on the primary side to each one of the secondary side to achieve 120 volts.

Kanza Education and Science Park
I-70 & MacVicar Ave.
Topeka, KS 66606

The Education Station is open to the public 365 days a year. School field trips are always welcome.
Contact Larry Robbins with USD 501 at 785-295-3063 or by email.

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