With the demand for sustainable solutions continuing to rise, more and more pressure is being put on utility companies to develop new or grow existing solar facilities. But as facilities either emerge or expand across the country, one thing that remains consistent is their need to place an emphasis on safety - especially reducing the risk of arc flash events. According to recent data from the National Fire Protection Association (NFPA), the National Safety Council and the Bureau of Labor Statistics, approximately 10 arc flash accidents happen every day in the U.S.

Damaging to personnel, equipment and operations, it is especially important to address risks at the transformer level. Because solar photoelectric generating facilities are stepping inverter voltages up to distribution and transmission level voltages, arc flash exposure is nearly unavoidable on live-front and dead-front transformers during commissioning and maintenance.

So how do you reduce the risk of an arc flash event? What are the latest solutions in the marketplace? And what can utilities do to help improve the safety of their employees and facility? Every solar collection site is different. Whether dictated by the facility itself, local jurisdiction or industry associations, each location has varying levels of safety practices designed to protect equipment and personnel from arc flash hazards. These guidelines include everything from the amount of personal protective equipment (PPE) needed, to on-the-job training requirements.

Moving outside the box

However, one of the most integral standards that all U.S.-based facilities have to adhere to is the NFPA 70E National Electric Code, which is the industry benchmark to protect people and property from electrical hazards. As new standards are released every two to three years, including new 2014 standards just released in August, the code is increasingly drawing awareness to arc flash hazards and instituting standards to help prevent incidents from occurring.

Although manufacturers offer a range of options to help protect sites and personnel against arc flash events, the latest and most potentially useful trend has been moving key components of the transformer externally. In fact, most facilities are choosing this design to avoid high voltage termination and low voltage bus contact to enhance safety during both measurement and maintenance operations.

As solar sites continue to rapidly expand, maintenance has become an increasingly important factor to maintain productive facilities. Prior to this solution, nearly every maintenance procedure required manually entering a live compartment, wearing a significant amount of PPE in order to help ensure the circuit was properly isolated. Beyond the added time it took to perform tasks, this method also provided an increased opportunity for personnel to encounter an arc flash hazard. With an external load break switch for operating isolating contacts and optional viewing window for added safety, professionals are able to visually confirm electrical disconnect and perform integral procedures externally.

Much like the focus on maintenance, measurement has also become a significant priority in the solar market. With readings serving as a primary indicator of potential issues or inefficiencies, there is a greater emphasis on comprehensive monitoring programs, with some even utilizing remote tracking centers. With the new design trend of moving tamper-proof temperature, pressure and oil level gauges externally, regular diagnostic readings can now be performed without personnel having to enter the low voltage compartment. This move allows a larger range of professionals to obtain the readings and requires less PPE equipment, reducing both cost and time.

Overall, the new external design modifications translate to enhanced safety, operational efficiencies and cost savings, all while helping to mitigate the likelihood of an arc flash event. While standards may continue to change and the industry may find new, effective solutions in the battle to combat these hazards, including high-speed fuses and enhanced circuit breaker solutions, arc flash hazards are proving to remain a threatening factor that will continue to impact solar utility operations now and throughout the industry’s future.

And, while one of the best ways for solar facilities to avoid risk is continued adherence to the high safety standards set by industry organizations, new technologies, such as external transformer components and remote monitoring, have proven to be both valuable and cost-effective solutions to reduce the occurrence of arc flash events. S

Adam Peterson is an application engineer for solar energy and data centers at Eaton’s Cooper Power Systems business.