S&C Distribution Automation Products Enhance Reliability at a New Airport.

Background

A previously rural area in the Southern United States was experiencing rapid residential, commercial, and industrial development. To support this growth, a new airport was planned. The local electric utility’s distribution system would require significant improvements to assure reliable power for crucial areas of the airport, including the terminal building, the air-traffic control tower, and the air rescue and fire fighting facility.

What did they do?

With two sources serving the airport, distribution automation would provide enhanced reliability through automated sectionalizing capability, dramatically reducing the duration and impact of any outages. This was the utility’s first distribution automation project, so they researched a number of equipment suppliers. They selected S&C because of its extensive experience with other airport projects. S&C Scada-Mate® Switching Systems, Remote Supervisory PMH Pad-Mounted Gear, and Source-Transfer PMH Pad-Mounted Gear were chosen for the application.

How did they do it?

The Scada-Mate Switches and Remote Supervisory PMH Pad-Mounted Gear were furnished with S&C Automatic Switch Controls including the IntelliTEAM® Automatic Restoration System. The IntelliTEAM Automatic Restoration System uses peer-to-peer communication and distributed intelligence to make operating decisions, accelerating the speed at which the system can respond to a disturbance. Neither central processing nor a SCADA system are required, though both are fully supported. Team members communicate with one another via Metricom Internal Wangate Radios.

The airport’s terminal building was determined to be the most critical load. Source-Transfer PMH Pad-Mounted Gear equipped with a Micro-AT® Source-Transfer Control was chosen specifically to serve the facility, in order to provide an even faster response to system disturbances. The Micro-AT is an advanced microprocessor-based electronic control that continuously monitors the condition of the two sources serving the gear. If the source serving the load is compromised, the control initiates a transfer to the alternate source, restoring power to the load.

The Results

After the airport started service, the new distribution automation system successfully operated for a number of disturbances on the distribution system, dramatically minimizing the outage duration at the airport.

One disturbance was an outage on the first source, caused by a faulty pole-top insulator. The IntelliTEAM system responded by reconfiguring itself to feed the entire airport load from only one of the feeders, a process that took just 35 seconds. The critical terminal building, served by Source-Transfer Pad-Mounted Gear, was only out for 2 seconds.

Another disturbance resulted from a cable fault, causing a substation recloser to operate. The IntelliTEAM system observed a programmed number of operations during the reclosing sequence, to determine if the fault was temporary in nature. After the recloser went to lock-out status, the IntelliTEAM system initiated switch operations to isolate the fault and restore power to as much of the load as possible. In the meantime, the source-transfer observed a loss of voltage, so it transferred load to the second feeder, restoring power to the terminal building after just 2 seconds.