An IED is an acronym. Like most acronyms, they often mean different things to different audiences. For example, to you, PLC may mean Power Line Carrier. To others in the SCADA market, PLC may mean Programmable Logic Controller. IED is another one that may mean two different things depending on your perspective, background, and experiences. Illustrating my point further, the IED acronym is also used in military jargon, but that type of IED is not the scope of this article.

In SCADA utility segments (either gas, water or electric), IED stands for Intelligent Electronic Device. It’s intended to serve as a generic term to cover a comprehensive class of products and applications. Regardless of the utility environment, these IEDs all have something in common—they are intelligent.

What do I mean by intelligent? Specifically, IEDs speak a protocol language and can perform automated actions based on their programming. With IEDs, utilities can save money by:

  • Removing the need for field visits;
  • Providing higher levels of monitoring and control;
  • Granting additional visibility to data; and
  • Improving overall reliability and outage metrics.

All of this is done through automation. By using IEDs, utilities are taking a giant step forward in their grid modernization journey. Much like traditional industrial factories, they are taking manual actions and making them automated. Let’s take a look at some common types of IEDs in each SCADA market:

Electric Utilities

For electric utilities, there are several application types of IEDs. Take a recloser for example. Reclosers play a critical role in reliability, self-healing networks, and improving residential customers uptime.

For example, if an overgrown tree touches a distribution feeder line that does not have an IED, a fault occurs and customers are without power. With an IED, a utility can program the recloser to perform a certain number of ‘shots’ or times a recloser will automatically close back to attempt to clear the fault. In this scenario, the tree branch briefly touches the line, the recloser opens, the downstream customers (homes) lose power, the recloser closes back in, and if the tree is no longer touching the line, power is restored to the downstream customers. With an intelligent recloser (IED), this happens automatically and within seconds (and possibly even sub-seconds).

So, the next time you are in the comfort of your house and the power goes out for around a second and comes back, you can make an educated guess that the recloser did its job.

Other use cases for electric SCADA IEDs include controlling voltage regulators, capacitor banks, switches, unit substation breakers, faulted circuit indicators, network protectors, relays and more. All of these intelligent devices can (and should) be added to your system to help improve reliability to your end customers as they all have a purpose on the grid. If the power is out, you are not taking in revenue and, more importantly, the customer is not happy.

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Water Utilities

In the Water SCADA market, there are several applications to consider for an IED. Most commonly, the use of a programmable logic controller (PLC) is used to automate field actions. For example, consider a scenario where a storage tank is being manually monitored for water levels, but still has the occasional overflow. Not only is this creating an environmental issue, but the water loss is missing revenue for the utility. By using a PLC, the tank can be continually monitored. If the tank reaches a certain high level mark, a PLC might create logic (Stair Step or Ladder Logic) to turn off pumps automatically.

Other types of IEDs in the water SCADA market include intelligent pump controllers, remote terminal units (RTU), lift stations, leak detection, pressure monitors, controllers at a wastewater treatment plant and much more.

Gas Utilities

In the Gas SCADA market, PLCs and RTUs are the dominant types of IEDs automating actions. With an RTU, the utility can connect to various industry standard sensors to provide monitoring and control to this industrial application. For example, consider pressure detection on a distribution gas line. If gas pressure reaches a critical level, it quickly becomes a public safety issue. The utility needs to operate a valve to redirect the pressure or it could result in an explosion.

Utilities forging into grid modernization are automating these actions to remove the need for manual intervention and improve overall reliability and safety. Further IED applications include valve control, gas regulators in a substation, methane detection, vault intrusion, flow rates and more.


Utilities that are using IEDs today are gaining tremendous insight into operations and are leading the charge towards a more modern infrastructure. The key to realizing the benefits of IEDs is to make sure that your communication network is not only dependable but can seamlessly integrate with your SCADA system. Once this is accomplished, the utility will not only save money, but your customers will benefit from a more reliable and ultimately, safer world.