Roller Coaster Hurtles Power System into Voltage Troubles

Roller coasters are known for an Up and Down ride experience - they're also known for Up and Down voltage fluctuations within a theme park, as well as on the utility feeder line. This application study outlines a Maryland theme park's solution to reactive power demands - two S&C PureWave AVCs were installed for reactive power management of the varying loads.

(PRWEB) January 23, 2004

The roller coaster at a theme park in Maryland can accelerate riders from a standstill to speeds of over 60 miles per hour in just 3 seconds. Linear-induction motors make this extraordinary performance possible. All electric motors contain a rotor that is magnetically pulled by the electromagnetic field of the stator. But in linear-induction motors, the stator is “unrolled”. In this application, the rotor components are integrated into the roller coaster and the stator components into the track. When the system is energized, the roller coaster rapidly surges forward.

All the excitement of the ride came at a cost to the electrical system of the theme park. To generate the torque needed to accelerate the ride, the linear-induction motors require brief but very large amounts of real and reactive power. The resulting current surges caused sags in the system voltage. These voltage sags prevented the cars from achieving the desired speed. In severe cases, “saddling” would occur . . . the cars did not have sufficient energy to crest the next hill and stalled on a low point in the track. To make matters worse, other utility customers served from the same feeder complained of annoying light flicker and voltage sags.

The Solution:

Manage the Ups and Downs in Reactive Power Flow with PureWave AVCs

Working with the local electric utility, the theme park operator installed a 4100-kVAR, 520-V PureWave AVCä Adaptive VAR Compensator on the secondary side of the transformer supplying power to the ride. A second PureWave AVC rated 2400 kVAR was also installed to provide transient voltage support on the utility feeder. The two units work in tandem to support motor voltage and eliminate flicker.

Remarkable Results

The PureWave AVCs have provided superior performance since their installation in 1999. Although peak reactive demand actually turned out to be much greater than expected, motor terminal voltage is now precisely maintained, so operation of the roller coaster is consistently successful. Additionally, flicker and voltage sag complaints from nearby neighbors have stopped.

S&C Electric Company, headquartered in Chicago, IL, specializes in the development and manufacture of innovative products and services for the electric power industry. S&C's family of PureWave® Power Quality Systems have been installed at critical-process facilities worldwide to deliver reliable protection from the power quality problems that can disrupt operation. Information about S&C is available at http://www.sandc.com/products/powerquality.asp.

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