When Hurricane Irene and an early snowstorm hit Orange & Rockland Utilities' service territory last fall, the storms wreaked the worst havoc ever. The hurricane knocked out 40 percent of the utility's 300,000 electric customers. Then an October snowstorm dumped nearly 20 inches of snow and the temporary loss of power to customers was even greater.
O&R was hardly alone, as utilities across the Northeast all were devastated by nature's double punch. But O&R already was working on several fronts to improve "blue sky day reliability," reduce storm-related outage and restoration costs and improve grid efficiency through coordinated voltage reduction, while deferring large capital investments to avoid a rate increase.
For a customer-facing explanation of the work, see O&R's recent press release.
O&R's efforts are reaching fruition this year and next, according to Charlie Scirbona, manager of smart grid engineering at O&R Utilities, a subsidiary of Consolidated Edison, Inc., with two subsidiaries of its own, serving a population of 750,000 in New York, New Jersey and Pennsylvania.
Taking a "model-centric approach" is fundamental to this work, Scirbona told me recently. Building on legacy systems, using well-vetted technologies and employing open architecture to avoid point solutions or getting locked into a single vendor also contributed to progress on this project.
The O&R project is part of a larger $272 million project—half funded by a Smart Grid Investment Grant of $136 million from the U.S. Department of Energy—undertaken by ConEd, O&R and other subsidiaries.
The O&R project is two-fold: add hardware and communications to five circuits and two substations, affecting about 10,000 customers in New Jersey, and use the equipment to optimize the economic performance of O&R's distribution circuits in New York.
Let's look at the model-centric approach first. (For more, see the case study on the smartgrid.gov website.) Today, O&R's system incorporates field devices such as reclosers and automated switches. The drawback to the present configuration is that these devices can only respond automatically to pre-programmed scenarios; events outside those parameters can cause those devices to shut down. O&R's model-centric approach, being built and tested on one circuit, will provide real-time data from many points on the circuit, allowing more accurate depiction of power flows. That will provide greater accuracy in understanding what's happening on the grid and allow more options for, for instance, rerouting power in an outage.
"In a model-centric system we have a very detailed model of the system that we continually run power flows on," Scirbona told me. "The model is hooked up in real-time to field devices, which constantly deliver real-time data. The power flow takes that real-time data and scales it between devices so that you have an accurate depiction of the system - every asset on the system, not just devices, but every wire, every transformer, the whole system. So the system has either a real-time value or a calculated value associated with it.
"It's situational awareness for the computer," Scirbona continued. "The computer now knows what's going on in the entire system. The computer is looking for a device in the field to change state or, let's say, clear a fault.
"The model-centric system will clear a fault automatically. That change of state is reported back to the computer system, which then polls all the devices on the primary circuit and its back-up. From that information, and having knowledge of the entire system, the computer makes a selection as to the best way to restore the system.
"Because it has knowledge of the system, the way the system re-routes on-peak may be different from how it re-routes off-peak," Scirbona added. "The response is designed to be sure that it doesn't violate any user-set parameters—such as emergency voltage levels or emergency loading levels—and maximize the number of customers that you restore."
Tomorrow we'll share the conclusion of this interview, which reviews the basic steps O&R took to add smarts to its grid.
Intelligent Utility Daily