Commercial Electricity: Understanding Power Distribution and Related Factors

Those who own or manage a business in Oswego, Naperville, Aurora, Yorkville or Plainfield know the importance of having dependable power for their office or building. What we might not always give thought to is how exactly power works in keeping us running to provide our products and services.

commercial electricity power distribution

Here we’ll share a brief overview of power distribution and related concepts of how power is effectively provided to commercial buildings. Beyond being further informed, you may find the information useful in managing your electrical supply and maintenance.

How Does Power Distribution Work?

Electrical power travels from the power plant to a commercial building through the power distribution grid. The plant transmits electricity most efficiently at very high voltages. In the U.S., power companies typically deliver electricity to medium and large buildings at 13,800 volts (13.8 kV).

Commercial power plants generate a three-phase alternating current (AC). They use AC electricity because it has much less line loss than direct current (DC) electricity does over long distances.

As three-phase power leaves a generator, it enters a transmission substation at the power plant. This substation then uses large transformers to convert the generator’s thousands of volts to high voltages for long-distance transmission on the transmission grid.

Next, the voltage from the transmission grid is adjusted down for the distribution grid, usually at 10,000 volts. A bus splits the distribution power in different directions toward the power’s consumers. Regulator banks along the lines prevent an excess or deficiency of voltage as it is delivered.

For smaller buildings and residential locations, the electricity moves through a transformer to a meter; this process adjusts the high voltage for consumer usage. Wires then transfer the power from the meter to a panel board, which is typically located in a basement, garage or utility closet.

The panel board will have a main service breaker and a series of breakers that control the power’s flow to various circuits in the building. Each branch circuit will serve a device (such as an appliance that requires a heavy load) or several devices, such as lights or convenience outlets.

Because large buildings have a much higher electrical load, the electrical equipment must have a greater capacity. In many cases, the building owner will provide and maintain their own step-down transformer for adapting the incoming high voltage to a more usable level.

With large buildings, the incoming high voltage will arrive at a meter and then move through a transformer. The electricity is then transmitted to switchgear, which distributes the power safely and efficiently to the building’s different electrical closets serving zones or floors of it. Buildings that are very large or that have complex electrical systems may include multiple transformers for feeding multiple pieces of switchgear.

What Is a Load-Flow Study?

A load-flow study is a numerical analysis of electrical power’s flow in an interconnected system. It usually uses notations such as a one-line diagram and a per-unit system based on AC power parameters.

Load-flow studies help in planning the future expansion of power systems and determining how existing systems can best operate at lesser cost. The main information gathered from a load-flow study is the magnitude and phase angle of the voltage at each bus (a metallic strip or bar for high-current power distribution) and the real and reactive power flowing in each line.

A load-flow study is particularly useful for a system that has multiple load centers, such as at schools, car dealerships and manufacturing facilities. It analyzes the system’s ability to supply the connected load. The total system losses and individual line losses are figured as well.

What Is Electrical Load Forecasting?

Unlike utilities such as water or natural gas, electricity cannot be stored; rather, it should be generated as soon as it is needed. Power companies use load forecasting to predict the energy needed to meet the balance between supply and demand. Accurate forecasts help to save greatly on operating and maintenance costs, increase the reliability of supply and delivery of power, and inform good decisions for future expansion and development.

Load forecasting can be short-term (a few hours), medium-term (several weeks or multiple months) or long-term (a year or more). Short-term forecasts are used for scheduling electrical generation and transmission. Medium forecasts assist with purchasing fuel. Long-term forecasts support the development of the power supply and delivery system.

These forecasts have become even more valuable to utility companies as patterns for demand have become more complex and hard to identify.

What Is the Power Factor?

The power factor assigns values for the efficiency of power consumption. It can be used to assess equipment, appliances, motors, buildings and industrial plants.

The assigned value is the ratio between “useful” working power (kW) and apparent power (kVA). It is determined by the formula PF (power factor) = kW / KVA.

A high power factor indicates efficient use of energy, and a low power factor signifies poor utilization. By calculating the power factor, we come to know how much value we’re receiving for the power we consume and pay for.

A useful analogy for the power factor is a glass of beer. Let’s say we purchase a pint at a tavern. The beer is poured and set before us. The glass contains both beer and a foam head. If we have less foam and more beer, we have a greater value from the pour. If the pour is, say, 25% foam, we have decreasing value.

Electricity consumption is similar. There will always be some that is “foam” that we pay for. For example, a computer monitor might have a power factor of 0.55, and a microwave oven might have one at 0.9. The microwave oven is much more energy efficient – i.e., it has less “foam.”

Why Are Power Panel Upgrades Important?

Regardless of how well a commercial electrical system was originally designed, a power panel upgrade will eventually become necessary.

For example, the panels in some older buildings in Oswego, Naperville, Aurora, Yorkville and Plainfield may have been installed when the universal demand for power was lower and technology was less sophisticated. An entire commercial building might have run on 60 to 120 amps with just a few circuits. Today, even small buildings and workshops use 200 amps. An older fuse panel might also need to be upgraded to a circuit panel for safety and insurance purposes.

A leading sign that your office or building might need a panel upgrade is that it doesn’t seem to have enough power to satisfy everything. For instance, lights are flickering or equipment shuts off for no apparent reason. Another indicator can be circuit breakers that frequently trip.

Safety codes continue changing as well. Some older panels might not be compliant and consequently be identified as fire and safety hazards.

A power panel upgrade is also a great idea if you are planning to renovate space or introduce new equipment that increases the power load, such as HVAC systems.

The Commercial Electrician Near You

Trinity Electrical Services serves Oswego, Naperville, Aurora, Yorkville and Plainfield with licensed, bonded and insured commercial electrical services. We help ensure you have the proper electrical system for your business requirements. If you would ever like to further discuss a panel upgrade or how commercial power supply works, we welcome the opportunity to assist you. Just give us a call at (630) 499-1492.

We are also commercial electricians for nearby communities such as Plano, Batavia, North Aurora, Montgomery and Sugar Grove.


"Thank you Phil. Your crew did a great job and we appreciate the service that was provided to us. Very efficent and professional. If we should have any electrical repairs/issues needed in the future, we will contact Trinity Electric again!"

Donnielle S. - Batavia, IL
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