Today's substations going digital

2018-01-03 - World Gen article by Steven A. Kunsman, ABB - December/January 2017
Today’s utility-scale wind and solar farms are always accompanied by a substation or two nearby. Equipment in the substation transforms voltage and governs the interface to the transmission grid. The substation plays a critical role and essentially acts as the motherboard of the power industry, controlling and directing power on demand, essentially making sure the lights stay on.

To do so, electrical substations have traditionally utilized miles of copper cabling for point-to-point connections measuring currents and voltages and controlling the circuit breakers for power switching and protecting the substation equipment. However, copper is expensive, has limited capacity for one measurement or a single control signal (important for power delivery and condition monitoring), and also introduces potential safety risks. This conventional design and aging control equipment results in costly testing and maintenance, and restricts the communication of important information useful for identifying an asset’s health and determining when equipment maintenance is required.

If operators were able to leverage digital technology and power system real time information availability, it would mean significant improvements in grid reliability, increased safety, and reduced power interruptions.

Enter the digital revolution. Digital substations reduce the electrical connection between high-voltage equipment, let the grid run more efficiently, and create a safer site. This is done by replacement of copper signal wires with fiber-optic connectivity. Additionally, the industrial internet of things (IIoT) is able to offer data on demand to optimize overall substation performance — often letting operators work from the comfort and safety of an offsite office.

Digital substations are not a new idea to the power industry, but the technology has been slow to adopt because of old processes, regulations, and an aging transmission grid. Times are changing, however, thanks to advances in fiber optic communications and digital technologies.

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