Wind Farm Arc-flash Safety

The wind energy industry's first switchgear solution, designed specifically to provide safer, more reliable and higher-performing wind farm operations, is now available from American Electric Technologies Inc. (AETI)-a supplier of custom-designed power delivery solutions for the traditional and renewable energy industries.

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The wind energy industry's first switchgear solution, designed specifically to provide safer, more reliable and higher-performing wind farm operations, is now available from American Electric Technologies Inc. (AETI)—a supplier of custom-designed power delivery solutions for the traditional and renewable energy industries.

Safety a Prime Wind Issue

The U.S. Bureau of Labor Statistics reports 212 workers lost their lives in 2008 from contact with electric currents. In 2007, 250 fatal worker injuries occurred; in 2006, 256 deaths were reported. These statistics include deaths from arc flashes, which are electrical explosions caused by low-impedance faults between ground and another voltage phase in an electrical system. Arc flashes tend to occur during initial power equipment start-up and during equipment maintenance.

Switchgear solution provides safer, more reliable and higher-performing wind farm operations.

Injuries from arc flashes range from minor injuries to third-degree burns, blindness, hearing loss, nerve damage, cardiac arrest and even potential death. Approximately 65 percent of arc faults occur during electrical maintenance when the equipment doors are open and an operator is standing in front of the equipment. Conventional arc-resistant switchgear, which channels the arc flash through vents away from the equipment and the operator, has limited arc-management capability—significantly compromising wind farm maintenance worker safety in confined areas and putting assets at risk.

The Occupational Safety and Health Administration (OSHA) reports they investigated 32 arc flash-related accidents in 2009, 38 in 2008 and 25 in 2007. Some industry reports estimate that the average cost a company incurs for medical treatment on behalf of each arc-flash survivor is $1.5 million, and total costs of litigation could reach up to $10 million. The industry-first wind farm switchgear is designed for safety, performance and reliability.

AETI is leveraging their 60 years of experience in deploying custom-designed power distribution equipment in the world's harshest environments to introduce the new, 40 kV wind farm switchgear. The switchgear is designed specifically for the wind power industry and breaks new ground in wind farm safety, performance and reliability.

Safety

AETI understands that more than 50 percent of arc fault injuries occur during electrical maintenance when an operator is standing in front of the equipment. By designing remote circuit breaker racking, maintenance workers can rack in and rack out the circuit breakers from a safe distance away. The switchgear also incorporates a ground safety switch, interlocked with the circuit breaker, enabling the operator to ground incoming cables during maintenance—reducing exposure to accidental electrical back feed. Most significantly, AETI's wind farm switchgear provides protection for high impedance faults where fault currents may not reach the required level to trip conventional breaker trip settings.

The system uses proven light-sensing technology to detect the arc-flash and sends a signal to open the circuit breaker—isolating the arc-fault within approximately 50 milliseconds.

Currently, the National Fire Protection Agency 70E guideline only requires special clothing and personal protective equipment be worn to mitigate the injuries. Even with these guidelines in place, companies would still need to rely on employees to consistently and correctly wear the gear, which does not always occur.

Performance

AETI's wind farm switchgear is designed to enable maximum wind farm power delivery to the grid. Unlike traditional 38 kV switchgear with limited peak duty, AETI's switchgear provides 40 kV power distribution at 3000A continuous duty—enabling more wind power to be delivered to the grid per collector line. The switchgear also has a 40 kA interrupting rating, enabling wind farm developers to connect to high-capacity power grids.

Reliability

The AETI switchgear system is designed for wind farm reliability. By offering 170 kV basic impulse level, the substation and wind farm are provided with increased resilience against lightening strikes. The system also uses vacuum-based circuit breaker technology that eliminates use of toxic sulfur hexafluoride gas and continual recharging maintenance services.


About AETI:
AETI offers M&I Electric power distribution and control products, electrical services, and E&I construction services, as well as American Access Technologies zone enclosures and Omega Metals custom fabrication services. South Coast Electric Systems L.L.C., a subsidiary, services Gulf Coast marine and vessel customers.

AETI is headquartered in Houston and has global sales, support and manufacturing operations in Beaumont, Texas; Keystone Heights, Fla.; and Bay St. Louis, Miss.

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