Electric Utility communications within a substation can be one of the most complex systems, depending on the utility, the number of substations owned by the utility, and age of each substation. Unlike data centers or other IT communications systems, Operational Technology (OT) communications within a substation utilize multiple types of communication transports, cable links and protocols that are added or layered into an existing system, based on the need. Over time, as new substation equipment is installed either within the yard or the control shelter, additional communication circuits can be provisioned and installed without having to overhaul the entire substation communication system. Depending on when the circuit was provisioned, the speed and bandwidth requirements, and the destination on the circuit, the type of communications technology that was utilized can vary drastically, including the cabling used to link equipment. Unfortunately, as utilities work to address cyber vulnerabilities, this tangled layer of communications equipment often creates the potential to overlook areas of exposure, or rather a cyber hole, especially when older legacy devices are prevalent. Communications with and between these devices must not be overlooked, as they need to be passively monitored in a similar manner as network devices. 

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Author: James Moralez, P.E., Maxwood Solutions, Inc.