Substations are where the power grid does much of its work: transforming voltages, switching circuits and protecting equipment. They are also increasingly digital and increasingly remote-managed, full of intelligent electronic devices that communicate over networks rather than hard wiring alone.
That digital, connected, and often unmanned nature makes the substation a security concern at the grid edge. Protecting it is largely about controlling who and what can reach the devices that operate the grid, and ensuring data can leave for monitoring without opening a path back in.
01Key takeaways
- 01
Substations are the digital edge of the power grid, full of intelligent electronic devices (IEDs) and RTUs.
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Protocols such as IEC 61850 and others were built for reliable operation, not for resisting attack.
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Many substations are unmanned and remotely managed, making remote access a central risk.
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One-way telemetry to control centers provides visibility without an inbound path to grid equipment.
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Engineering and vendor access should be controlled and time-bound, and substations fall under NERC CIP in North America.
02The substation as the grid edge
A substation steps voltage up or down, switches and routes power, and protects the grid from faults. Modern substations do this with digital control and protection systems that monitor conditions and act in milliseconds to keep the grid stable.
Because substations are distributed across the grid and often operate without staff on site, they are managed remotely. That makes them a critical and exposed edge: essential to grid operation, numerous, and reachable over networks.
The substation is where the grid becomes digital, distributed and remotely reachable, which is exactly what makes it worth protecting.
03IEDs, RTUs and protocols
Inside a modern substation, intelligent electronic devices handle protection and control, while remote terminal units and gateways connect the substation to control centers. These devices communicate using substation protocols, including the IEC 61850 family and others used for telemetry and control.
Like other OT protocols, many were designed for reliability and speed rather than security, often without strong authentication. A device that can reach an IED over the network may be able to influence protection or control functions, which is why limiting that reach matters so much.
04Remote and unmanned site exposure
Most substations are unmanned for most of the time, relying on remote monitoring and control from central operations. This is operationally necessary but creates security exposure that has to be managed deliberately.
- Remote access paths into the substation for operations and engineering.
- Communications links to control centers that carry both telemetry and control.
- Vendor access for maintaining protection relays and other devices.
- Limited physical security at remote sites compared with staffed facilities.
05One-way telemetry to control centers
Control centers need a continuous flow of data from substations: measurements, statuses, alarms and events. Much of this is publication: the substation reports outward, and the control center observes.
For the monitoring portion of that flow, a one-way path keeps the data moving while removing an inbound route to substation devices. An AIRGAPNET controlled connectivity pattern can also keep certain access paths disconnected by default, so a substation publishes its state continuously while exposing no standing path back to the protection and control equipment.
Separating monitoring from control in this way reduces what an attacker who reaches the monitoring side can do.
06Controlled engineering access
Substations periodically need engineering work: updating relay settings, maintaining devices, and responding to issues. This access is occasional, which means it does not need to be permanently available.
- Replace standing remote access with time-bound, approved sessions.
- Broker access through controlled intermediaries rather than direct exposure.
- Keep the engineering path disconnected by default between sessions.
- Log every connection so substation access is provable.
07The NERC CIP context
In North America, substations that are part of the bulk electric system fall under NERC CIP requirements, which mandate controls such as electronic security perimeters, access control and monitoring around critical cyber systems.
Substation security is therefore both an operational and a compliance concern. Controls that limit electronic access and provide evidence of it support CIP obligations, and reducing reachability aligns naturally with the electronic security perimeter the standards expect.
08Closing thought
Substations turned the grid edge into a network of digital devices that can be reached and managed remotely. That brought real operational benefits and a real security responsibility, because the equipment that protects and controls the grid is now reachable over networks.
Let substations publish their state outward for monitoring, keep control and engineering paths reachable only when genuinely needed, and treat reachability as the thing to minimize. The grid edge is safest when its devices are visible but not openly reachable.
FAQFrequently asked questions
Why are electric substations a cybersecurity concern?
Substations are the digital, distributed edge of the power grid, full of intelligent electronic devices that operate protection and control. They are often unmanned and remotely managed, so the equipment that runs the grid is reachable over networks.
What protocols do substations use?
Modern substations use protocols including the IEC 61850 family and others for telemetry and control between intelligent electronic devices, RTUs and control centers. Many were designed for reliability and speed rather than strong authentication.
How does one-way telemetry help substation security?
Control centers mainly need substations to report outward: measurements, statuses and alarms. A one-way path carries that data while removing an inbound route to substation devices, so reaching the monitoring side does not grant access to protection and control equipment.
How should substation engineering access be handled?
Engineering work is occasional, so access should be time-bound and approved rather than standing, brokered through controlled intermediaries, kept disconnected by default between sessions, and logged so every connection is provable.
Do substations fall under NERC CIP?
In North America, substations that are part of the bulk electric system fall under NERC CIP, which requires controls such as electronic security perimeters, access control and monitoring. Reducing reachability aligns with the electronic security perimeter the standards expect.
SRCSources of record
Visible, not openly reachable
Let substations report out without a path back in.
Publish substation state one way for monitoring and keep control and engineering paths disconnected by default, opening them only for approved, logged windows.