Advanced Generator Control Offers Flexibility at Eglin AFB

One of the largest Air Force bases in the United States has discovered a way to manage its remote power backup system with greater efficiency and more flexibility than ever before. In the process, new management options have become available that will enhance the reliability and cost-effectiveness of base operations.

Eglin AFB is a large, complex facility with nearly 90 generators spread over 724,000 acres. Maintenance and control of these units is a challenge for Dave Lewis, power support systems maintenance supervisor at Eglin. Lewis recently completed his evaluation of a remote control network composed of six diesel generators and a central base station. The system performed exceptionally well, and Lewis has ordered the equipment to install another six remote sites.

“One of the great benefits to this system is its flexibility,” said Lewis. “Each generator site can be programmed for a different level of sensitivity to voltage and frequency fluctuations, depending on what type of equipment is served by the unit. We can even monitor fuel levels and ambient conditions at each location from right here in the office.”

GenCom 2000, manufactured by Sutron Corp. of Sterling, Va., is the remote monitoring and control system that Lewis uses at Eglin. Employing a mixed network of copper and cellular telephone modems as well as line-of-sight radios, a single base station can monitor conditions at any given generator site and perform multiple tasks, such as starting and stopping the engine, loading and unloading, measuring power output and monitoring a dozen critical data points.

The ability to monitor fuel levels, engine performance and power output from a central location makes it possible to use the generator network for more than just backup power.

“Peak power management is something that we’re really interested in,” said Lewis. “Under peak conditions we can generate our own power for a lot less money than we can buy it. It’s a way to use our resources more wisely.”

Without the remote capability, someone would have to drive to each generator to start and stop the engine, check on fuel levels, load and unload, etc. Such physical limitations make it impractical to implement a peak power management strategy on a meaningful scale at an installation as large as Eglin.

Eglin AFB is located on the Gulf of Mexico in Florida’s panhandle, an area prone to tropical storms and other severe weather conditions. Reliable backup power systems are essential to ensure the integrity of base operations. Maintenance, measurements and system exercise must be performed at least once a month to ensure reliable backup power. With a remote monitoring and control system, many of these tasks can be performed from the central base station, greatly reducing the level of effort required and reserving skilled personnel to be used more efficiently.

The key to base station operations is the GenCom system software, a multi-user program with a graphical user interface running on a Windows workstation. The software is password protected and provides three levels of security:

  • Operator-level access allows a user to monitor conditions at a particular site and acknowledge alarms only.
  • User-level access allows a user to additionally start, stop, load and unload a generator but not to change system configurations.
  • Administrative-level access allows a user full access to all system functions, including fault and performance thresholds at individual sites as well as profiles for all other users.

After a user logs on, he or she simply selects a remote site from a pull-down menu and clicks the “OK” button. In a few moments, the GenCom monitor screen appears and displays the latest generator, engine and alarm data. Each generator site can be programmed to issue an alarm on any of 14 possible conditions (see table). Three of the alarm conditions are user definable and can be used to detect a switch closure or change of state on any external circuit or custom sensor the user wants to monitor. When an alarm condition is detected, the control panel at the generator can dial up to two pager numbers by telephone in addition to contacting the GenCom base station. Depending on system options, the control panel also can issue spoken alerts by telephone using digital voice technology.

When an alarm message is received at the base station, the alarm dialog is displayed. Lewis has configured his system to automatically print this screen so that a hard copy report of the alarm condition, including date and time, is created regardless of whether an operator is present at that moment. Alarm conditions are latched at the remote site until acknowledged, thus helping an operator or engineer track down momentary or intermittent alarms.

In addition to the obvious management benefits, the system also enhances the performance of Eglin’s 24-hour standby personnel. Using standard digital paging technology, standby personnel can be alerted to a problem instantly, no matter where they are.

According to Pete Nyberg, application engineer for GenCom, most installations are configured to auto-start and transfer power in the event of a power outage. About 20 percent of GenCom’s customers prefer to have direct control of the generator start-up and power transfer from the base station. This is no problem-GenCom system users can easily select from a variety of control and monitoring options.

Another benefit of the system is the ability to monitor ambient conditions at the generator site before starting a unit. At Eglin all the remote generators are diesel-powered units, ranging in size from 10 kW to 1.4 MW. During the colder months, the base station operator is able to check engine temperature before starting the unit for periodic exercise and testing. This makes it easy to keep track of how each generator performs under adverse conditions and enhances the overall reliability and integrity of the backup power network.

Installation is straightforward and was easily accomplished using on-site personnel on both new and existing units. The control panel for each generator comes pre-assembled and includes a keypad, LED display and battery backup. All of the alarm thresholds and operating parameters can be programmed directly at the panel or remotely from the base station. The panel comes complete with mounting hardware, communications equipment, wiring diagram, user manual and system software. The documentation includes a list of additional materials required such as cables, EMT conduit and miscellaneous hardware needed to mount the various sensors. A full set of engine and generator sensors are included.

Advanced digital technology for remote monitoring and control allows Lewis to make better use of Eglin AFB’s existing resources and also offers new opportunities for smart power systems management in the future.
Sutron Corp. Inquire R.S. 120

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