Breaking Free of Battery Backup

Innovative rotary power protection and conditioning technology keeps rail operations on track despite glitches in utility power and momentary loss of utility supply

Faced with the need to protect critical operations from utility power interruptions and other power-quality problems, Danny Woodbeck, maintenance supervisor at Canadian National Railway’s Symington Yard in Winnipeg, MB, took an unconventional approach. Working closely with Meridium Power, he harnessed the energy from a low-speed flywheel in an innovative motor-generator set developed by Precise Power Corp. to power his way through momentary power interruptions and other power-quality concerns.

The electro-mechanical system provides protection similar to that of a double-rectified, battery-based power protection system, producing an output with a constant frequency and regulated voltage for critical loads. The system uses stored energy from the integral low-speed flywheel to ride-through momentary power interruptions, eliminating the need for large battery-banks with their high maintenance and replacement costs. Keeping a lid on costs is an important consideration for Woodbeck as his company strives to compete in the competitive North American transportation market.

This system has eliminated power interruptions to the rail yard’s communications equipment and humping and intermodal operations, which previously caused major disruptions in shipping schedules. Woodbeck points out that any delays at the yard can quickly ripple throughout the entire rail network, costing the railroad thousands of dollars in penalties for late deliveries. At the same time, this innovative approach saves Canadian National money by eliminating the infrastructure and maintenance requirements of the large battery banks used in conventional systems.

The Need for Protection
Symington Yard, one of the largest humping switch yards in North America, is a major hub for Canadian National’s domestic east-west traffic and trains headed to and from the United States. Here, cars from arriving trains are uncoupled and re-assembled into outbound trains headed for a variety of destinations. With about 130 miles of side-by-side tracks covering the 650-acre site, the yard has a capacity of 4,300 railcars at one time and processes about 2,000 cars a day around the clock.

In addition to switching activities, the yard also features large shops for maintaining diesel-electric locomotives, railcars and electronic equipment, a weigh facility, and a general maintenance facility. An extensive customer-owned distribution system services the yard, providing electrical power to operations across the expansive yard.

Railcar Humping
The most striking feature of Symington Yard is the humping operation where radio-controlled locomotives push a train of railcars to the top of a rise, where each car is released down a gently sloping track. Gravity then takes over and carries the cars though a series of computer-controlled track switches and rail-mounted wheel retarders that control the speed of each car and direct it to the appropriate track where it gently couples with a preceding car to form a new train.

Minor glitches and momentary interruptions in the utility supply to the humping operation pose a serious threat to these activities. Migrating Canada geese in the spring and fall that feed on grain in the yard are a major problem. When startled, these large birds often fly into power transmission lines, creating phase-to-phase faults that cause disruptive power outages.

For years, the yard’s operations went unprotected from power interruptions causing frequent downtime and service disruptions. Battery-based equipment used to protect the computer system monitoring the operations was expensive to maintain and required frequent battery replacements. Batteries generally used in this type of application last no more than five to 10 years and replacement can represent up to half the cost of installing such a system.

By the fall of 2001, the entire battery backup system had reached the end of its useful life and had to be replaced.

Communications
Earlier that year, Canadian National commissioned a new communications center at Symington Yard, which serves as the main hub for Winnipeg-based communications. The center is the primary fiber hub for railroad’s Prairie Region, routing communications for most areas of the company’s operations. They include Canadian National’s call center located in Winnipeg, intermodal operations, rail-yard communications and switching, inter-satellite yards, and the centralized traffic control system that controls and monitors track signals across the Prairie Region. This vital facility requires high-quality, reliable power to prevent any interruptions that immediately impact the company’s operations across North America.

More at http://distributedenergy.com/may-june-2006/innovative-rotary-power-2.aspx