Fast-Track Theater Rebuild Defies the Odds

Apr 1, 2000 12:00 PM, Edited by Ellen Parson, Managing Editor

Electrical system design, theater construction occur almost simultaneously.

Supplying a 6000A, 480V electrical distribution system was just one precedent electrical contractor Harold Mast helped achieve during the $30 million rebuild construction job of the new Sight & Sound Theatres Millennium Theatre, Strasburg, Pa. In the 162,000-sq-ft theater, a typical performance activates 12,470V of electricity, 260 miles of wire, 26 miles of conduit, 1 million watts of lighting, 6700W of sound, 120 technicians/actors, 125 computerized creatures, and 80 live animals. The theater, which replaced one destroyed in 1997 by fire, boasts the largest moving light system on the East Coast, with 52 motorized lights and 1,500 stage lights.

Distributing and managing power for such a large complex presented several challenges, beginning with determining the size of the electrical service. The previous service had been upgraded to 4000A. But more power was needed for the new, larger facility.

Because Sight & Sound wanted to expedite power resupply to an existing production facility and trailers housing temporary offices, Mast, of Mast Electric, Leola, Pa., needed to design and order new switchgear ahead of schedule. He turned to Square D for help.

Mast and Square D's Mike Quickel approached the local utility, Pennsylvania Power & Light (PP&L), about the theater's electrical service needs. It had never supplied a 6000A service and didn't stock a transformer big enough to handle the load. To accommodate the service, Mast installed two 2000kVA pad mount transformers, which provide parallel feeds into the theater's two main circuit breakers.

With three daily shows performed 45 min apart, flawless backup power is critical. Mast and Quickel conferred with PP&L about using Square D switchgear to achieve a seamless transfer to backup power. The utility agreed to an unprecedented arrangement: allowing the theater's three generators to be synchronized to PP&L. At Sight & Sound's discretion, circuit breakers in the switchgear close, connecting the generators to the utility's bus. After generators pick up load approximately equal to the building load, the main breakers to the utility open. A similar process happens in reverse to return the load to the utility.

In case of unexpected power failures, utility breakers open before the generators come online. When the utility feed returns, generators synchronize with the utility. Main breakers to the utility close, generators ramp down their load, then they go off line.

Moving on such a fast-track project, technicians set up electrical distribution by working from blueprints that weren't even finalized. After establishing electrical service, the team focused on managing power. Sight & Sound selected the ALTIVAR variable frequency drives with ModBus communications protocol for tying together a network that controls stage curtains. Ten POWERLINK breaker panels provide and control power to lighting fixtures and equipment that require "constant" power rather than dimmer circuits. A POWERLOGIC power monitoring system enables the staff to manage power from a central control room. Circuit monitors installed on switchgear gather and control data, perform true rms metering and record problems like harmonics or voltage sags and surges from the utility.

This flexible service provided Sight & Sound Theatres with the answer it was looking for from an electrical contractor: a complete solution.