Siemens has embarked on a road to develop a high-speed, decentralized distribution feeder automation system that expands its distribution automation portfolio.

The decision to move in this direction was based on three major requirements: a future-poof solution that uses only recognized communication standards; a system that must provide high-speed fault location to start rapid feeder reconfiguration; and a system that must be scalable to provide cost-effective applications from a source-transfer application for a critical load to a fully automated Fault Location Isolation and Service Restoration (FLISR) system.

The following technologies were chosen to form a base for the solution:

  1. The IEC61850 communication protocol with peer-to-peer capability forms the basis for all data communication between devices.

  2. WiMAX was chosen as a platform for the IEC61850 systems based on its high-bandwidth and long-haul capabilities. The RuggedComm RuggedMAX Hardened Wireless Broadband WiMAX system was chosen for this solution.

  3. The protection relay selected was the SIPROTEC 7SJ80 with high-speed PLC functionality.

Siemens had no problem finding a partner to deploy such a system in a pilot project. The partner, A&N Electric Cooperative, serves customers on the eastern shore of Virginia, U.S. Kelvin Pettit, vice president of system reliability, and Tom Larson, vice president of engineering, immediately realized the power in the scalability of this system. According to Pettit, A&N needed a cost-effective solution to address its need for automation of some critical loads. A&N had a distribution feeder in its network feeding a critical hospital load that was controlled manually. An outage caused by a fault in the connected feeder could lead to a long outage before the system could be reconfigured to supply power to the hospital from an alternate substation source.

Deploying the new system would provide A&N with an automated, high-speed solution for the transfer of substation sources 20 miles (32 km) apart to feed this critical load. In addition, the system would provide high-speed FLISR functionality to this feeder, greatly enhancing reliability.

According of Andre Smit, senior product development manager for Siemens, faults are detected in less than 0.1 sec and automation-switching sequences on this feeder are completed in less than 0.4 sec. “We are confident that A&N's customers will not even be aware that switching was performed to optimize the feeder and to keep the maximum number of customers connected to a stable supply of power.”

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