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Understanding the Grid

May 31, 2023

Here at I&M, we realize that you don’t think much about how your power works – until it doesn’t.  Sometimes outages happen as the result of storms, or an accident that results in a vehicle hitting one of our poles.  And yes, sometimes outages happen because of squirrels on lines. 

Over the next few months, we’ll be sharing information about how power moves, explain the grid and talk about steps we must take sometimes to protect the grid.  First, we’re going to introduce you to PJM Interconnection and the grid.

The Grid

When we refer to the grid, we’re talking about infrastructure. The grid is made up of the  generators that make power, along with all the poles, wires and transformers that allow power to move across large areas until it reaches its destination – your home or business.  I&M is part of a larger regional power grid that is overseen and monitored by an organization called PJM Interconnection.  PJM not only monitors the flow of electricity for customers in Indiana and Michigan, but it also controls power flows to 65 million customers across 13 states as well as the District of Columbia. 

PJM serves as the “traffic cop” for the grid, coordinating how electricity moves across its service territory. It is responsible for ensuring the safety, reliability and security of the power grid throughout its territory. 

PJM monitors how much power is being generated – from sources including nuclear energy, solar, wind and water – by I&M and other power plants throughout its 13-state region. It also monitors how much energy is being used and the status of that power flowing through high-voltage transmission lines.

Occasionally, PJM determines that the amount of power being generated and transmitted may not meet the demand of all 65 million customers represented by the utilities in PJM’s region. Or it might detect issues with the grid’s infrastructure. Both situations could cause uncontrolled, catastrophic consequences for power reliability if not addressed. 

Therefore, in those situations, PJM alerts power companies like I&M to take certain steps to protect the grid, including asking customers to voluntarily conserve energy or through a controlled process to proactively shut off power by rotating outages. What that means is that instead of shutting off power to all customers at the same time, we will shut off power for a short amount of time to a smaller group of customers, turn it back on, and then repeat the process with the next group.  This is repeated until the situation is resolved.

 Since the entire power grid is connected, an issue in another state can even affect customers in I&M’s territory.

In a subsequent story, we’ll talk about some of those steps mentioned above in greater detail and how they might affect you and other customers.  If you want to learn more about PJM and the grid in the meantime, visit www.pjm.com

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