Safety a Prime Wind Issue
The U.S. Bureau of Labor Statistics reports 212 workers lost their lives in 2008 from contact with electric current. In 2007, 250 fatal worker injuries occurred and 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. 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.
Industry-first wind farm switchgear 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 with the company’s wind farm services experience, to introduce new, 40kV wind power switchgear at the Renewable World Energy Conference and Expo North America in Austin. The switchgear is designed specifically for the wind power industry, and breaks new ground in wind farm safety, performance and reliability.
AETI understands that more than 50 percent of arc faults injuries occur during electrical maintenance when an operator is standing in front of the wind turbines. By designing remote circuit breaker racking, maintenance workers can rack in and rack 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.
AETI’s wind farm switchgear is designed to enable maximum wind farm power delivery to the grid. Unlike traditional 38KV switchgear with limited peak duty, AETI’s switchgear provides 40KV power distribution at 3000A continuous duty, enabling more wind power to be delivered to the grid per collector line. The switchgear also has a 40KA interrupting rating, enabling wind farm developers to connect to high-capacity power grids.
The AETI switchgear system is designed for Wind farm reliability. By offering industry leading 170 kV basic impulse level (BIL), the substation and wind farm are provided increased resilience lightening strikes. The system also uses vacuum-based circuit breaker technology that eliminates use of toxic sulfur hexafluoride (SF6) gas and continual recharging maintenance services.
"We are pleased to bring our rich history of manufacturing first-rate power distribution gear to the wind and renewable energy markets," said John Skibinski, AETI’s vice president of renewable markets and chairman of the American Wind Energy Association (AWEA) wind reliability task force. "We are even prouder to provide safer, higher performance and more reliable switchgear to the industry."
The company will be exhibiting at the 2010 Renewable Energy World Conference & Expo North America in Austin February 23-25 in Booth 159, and will be available to discuss the new 40kV arc-mitigating switchgear technology for safer wind farm deployments.
American Electric Technologies, Inc. (Nasdaq:AETI) is the premium global supplier of custom-designed power delivery solutions to the traditional and renewable energy industries. AETI offers M&I Electric(TM) 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. In addition, AETI has minority interests in two joint ventures, which have facilities located in Xian, China and Singapore.