Through the Gridapp Consortium, DTE Energy and the S&C Electric Co. Have Teamed Up on a U.S. Department of Energy (DOE) pilot project to test and install the new TripSaver Dropout Recloser. The goal of the GridApp Consortium is to reduce research and development cycle time, transition technologies by improving interoperability, and accelerate the implementation and deployment to meet the near-, mid- and long-term needs of the Smart Grid.

DTE Energy (Detroit, Michigan, U.S.) has been a strong advocate of finding new and innovative ways to modernize the electrical grid. This pilot project is no different, with its goal to find a new tool that can relieve some of the traditional reliability issues that have hindered utilities and their customers in the past.

During electrical fault conditions, the TripSaver features an open-close-open-dropout operating sequence with a 5-sec reclosing time interval. The major advantage is that it provides an opportunity to reduce the number of temporary faults that cause permanent outages. It is expected that this product will have a high impact on utility standards concerning outages caused by temporary electrical faults on the electrical distribution system.

The DTE Energy-led pilot project, funded through the GridApp Utility Consortium, will be beneficial to many stakeholders — the electric utility industry, the manufacturer and, most importantly, electric utility customers.

BENEFITS TO THE UTILITY INDUSTRY

This GridApp pilot project has provided a unique opportunity for DTE Energy, as well as the entire electric utility industry, to become embedded into a manufacturer's process for final product improvements. Working directly with the manufacturer during the product-development stage allowed for advancements that support the market's needs.

Mark Kluka at the DTE Energy Power Laboratory performed electrical testing during this project. The physical testing and handling analysis was completed at the DTE Energy Overhead Lines Center of Excellence by Max Agge, an experienced DTE Energy overhead lineman, with the assistance of the IBEW Local 17 union safety director. The parties collaborated to provide input to S&C Electric Co. (Chicago, Illinois, U.S.) that led to modifications of the TripSaver devices.

DTE Energy has installed six of these reclosers on two distribution circuits. These distribution circuits have miles of single-phase lateral distribution lines passing through rural, heavily treed areas. Each of the installation locations are being monitored remotely using GridSense LineTrackers and cellular communication technologies to document and validate the field application.

BENEFITS TO THE MANUFACTURER

As an addition to the product testing performed, S&C has encouraged recommendations from DTE Energy and the GridApp Consortium. Throughout the analysis and testing, working group conference calls facilitated information flow to support product testing and enhancements. The technical design and testing input supported design modifications to provide product improvements. The manufacturer was willing to entertain the utility input focused through the GridApp Consortium, bringing multiple utility influences through a single point of contact. Delivering a utility-friendly product to market is much more achievable when the end users can provide input early on. This project has created a win-win opportunity.

BENEFITS TO THE CUSTOMERS

The most important beneficiary of this pilot project will be the electric utility customers, not only in DTE Energy's service territory, but everywhere this technology is deployed on overhead distribution circuits. Traditionally, utilities have used two methods for overhead lateral circuit protection: fuse blowing and fuse saving.

The first method uses a lateral fuse that is coordinated with a substation feeder breaker. The lateral fuse clears downstream faults, while keeping other customers served by the main circuit uninterrupted. However, even a temporary fault may cause the lateral fuse to blow, interrupting service for all customers on the lateral distribution circuit. The utility then must support a service crew call out, replacing the fuse link to restore service to the customers.

As an alternative, a utility may use a fuse-saving methodology, in which the substation circuit breaker (or an overhead recloser) is programmed to operate before the downstream lateral fuse. While this approach saves fuses, it also affects all customers served by the substation feeder breaker or overhead recloser. The first trip of the substation feeder breaker or overhead recloser is set for an instantaneous trip. This will force a breaker operation that is faster than the lateral fuse clearing time, allowing the fault downstream of the lateral fuse to clear. A second breaker trip programmed to operate more slowly will allow sufficient time for the opening of the lateral fuse if the fault is still present. This operation saves the fuse during instantaneous fault applications, but causes customers on the distribution circuit to experience a momentary interruption for all faults at any location on the substation feeder or beyond an overhead recloser.

Both methods of protecting overhead lateral circuits result in unwanted consequences. TripSaver will aid in diminishing momentary and sustained outages for customers, directly increasing customer satisfaction.

A THOROUGH EVALUATION

DTE Energy will maintain the field trial devices throughout 2008. Following the field trial, DTE Energy has the option of replacing the pilot units with new TripSaver devices. Upon removal, the devices will be returned to the manufacturer for evaluation.

At the completion of this project, DTE Energy will provide a detailed report to the members of the GridApp Consortium and the manufacturing partner to describe the results from the electrical testing and field installation. The goal of this evaluation is to support the advance of electric utility infrastructure throughout the 21^st century. DTE Energy provided utility knowledge and testing for the advancements and application of the TripSaver to support the Smart Grid needs. This project has supported all of the GridApp Consortium utilities and will help the utility industry in supporting the modern grid, while providing improved customer service.

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Nick Carlson is an engineer at Detroit Edison. In his five years there, Carlson has worked as both a distributed resource planning engineer and a distribution relay engineer. He has project managed multiple installations of distributed generation on the Detroit Edison electrical distribution system. Carlson holds a BSEE degree from Michigan Technological University and will complete his MBA from Wayne State University later in 2008. carlsonn@dteenergy.com

Haukur Asgeirsson is the manager of Power Systems Technologies at Detroit Edison, responsible for employing distributed resources into the distribution planning and operating process. Since 2002, he has installed 20 projects to support the distribution system totaling nearly 20 MW. His group also manages interconnections and is a champion of Smart Grid technology solutions. Asgeirsson received his BSEE and MSEE degrees from the University of Michigan. He is a member of the IEEE PES and a registered professional engineer in Michigan. asgeirssonh@dteenergy.com

ADVANCED GRID APPLICATIONS CONSORTIUM

The Advanced Grid Applications Consortium (GridApp) is a group of utilities that joined together to help improve the U.S. electrical grid. GridApp provides a fast-track process for engineering development, demonstration and validation of selected high-impact technologies for the electric utility industry.

The mission is to transition best technologies and best practices into broader use by member utilities. The sponsor organization is the U.S. Department of Energy Office of Electricity in conjunction with funding from member utilities. The GridApp organization was founded in December 2004 and in its short history has included the following utilities: AEP, FirstEnergy, Idaho Power, ConEd, Portland General Electric, DTE Energy, Salt River Project and Exelon.

Additional information about GridApp and how to become a member can be found at www.GridApp.org.