On Tuesday, October 20th, 2015, at the annual meeting of IAS, the Democritus University of Thrace SB IAS Chapter visited Oncor Microgrid. Oncor operates the largest regulated distribution and transmission system in Texas and the sixth largest in the United States. The site of the Oncor Miocrogrid is established in Lancaster, Texas, just south of Dallas. Oncor facilities also include a demonstration center to showcase the new microgrid, simulate how it works, and explain the benefits to visitors.
The tour schedule included a visit to the immersion room, the control room and an on-site visit to the facilities, so that attendees can obtain comprehensive information on the activities of the microgrid.
At first, the company’s activities were presented in the immersion room through interactive audiovisual material, explaining to us the feasibility and utility of a microgrid. Furthermore, in the same room, we viewed seven screens displaying the history of the grid and an explanation of its technology. We also watched as the fully functioning grid reacts to a simulated event such as extreme weather. Switching devices respond to clear the fault, isolate the
section where the fault occurred, and restore service from an alternate source. In addition the guide noted that the main scope of the microgrid is to ensure uninterrupted delivery of power for its customers– even during extreme weather events or other emergencies. Consequently, a microgrid operates independently or in conjunction with a main grid and avoids single points of failure.
The tour then continued in the control room of the microgrid. In this room, the attendees had the opportunity not only to see the real time energy management of the microgrid but also learn about how it is implemented.
During the demonstration the guide explained that turning diverse assets into a microgrid capable of operating independently or together requires a distribution automation architecture to leverage multiple intelligent grid solutions while enabling it to operate independently or as one microgrid. Oncor Microgrid implements a fault-tolerant approach based on energy storage devices to store energy from either the utility feed or any of the facility’s generation sources. In addition to providing the voltage signal for the site, this design enables renewable integration, controls the microgrid frequency, and is the first generating source to respond during an unexpected loss of power. For instance, in the event of a power loss caused by extreme weather, the microgrid’s distribution automation equipment “islands” the system and autonomously switches to alternative distributed power sources as needed. Acting independent of the main grid, the new microgrid system automatically restores power with minimal service interruption.
The two key components of Oncor Microgrid are the PowerLogic Microgrid Controller and the StruxureWare Demand-Side Operation. As regards the Microgrid Controller, it provides real-time management of distributed generation resources to ensure the right balance between the energy produced and consumed. The controller also safeguards operations and switches seamlessly from a grid-connected mode to an off-grid mode to ensure a reliable source of power for critical loads. As for the StruxureWare Demand-Side Operation, it provides a cloud-based platform for economic dispatch and forecasting. This software forecasts and optimizes where to produce, consume and store energy, based on external events such weather forecasts, demand-response events and tariff rates. This signifies that the microgrid not only looks at the technical aspect of this, but also the economic and regulatory side. Through those details, the visitors managed to grasp how microgrids and distributed energy resources can make the grid better.
Afterwards, attendees had the opportunity to see up close some of the microgrid plants, such as the solar photovoltaic arrays, the microturbine and the energy storage system.
Finally, we would like to thank all the contributors of the tour to the Oncor facilities for their excellent presentation and explanation of the structure and function of a modern microgrid.
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