The era of air insulated switchgear has passed
Shielded solid insulation increases reliability of medium-voltage switchgear and is appropriate for many upgrades, especially in oil & gas applications. In 2018, oil & gas companies must navigate a new normal. Political, technological, and societal changes are impacting the industry. Oil & gas leaders are taking a closer look at how their companies operate and how to address success in a modern way.
According to research group McKinsey & Co., healthy oil & gas companies deliver twice the level of returns to shareholders compared with the unhealthy. To achieve health, it’s recommended that oil & gas companies increase innovation alongside operational discipline, impart flexibility to the operating model, empower leaders, and attract and retain the upcoming generation of employees.
Oil & gas leaders have always valued standards, compliance, and safety, with innovation coming in as a late fourth. This period of workforce transition could be helped by fostering innovation, whether it be adding a new technology or implementing connected solutions.
Time for an upgrade
Within the past 50 years, medium-voltage switchgear designs haven’t changed much. But like today’s workforce, electrical distribution technology also is in a period of transition. It’s time for oil & gas operators to reevaluate existing medium-voltage switchgear applications.
Traditionally, in North America, medium-voltage switchgear has been air insulated, meaning that the principal method for achieving dielectric stability rests on enough air gaps between phase conductors. While air insulated switchgear has been the accepted solution, the widespread use of bus differential protection schemes indicates lingering doubts about air insulated switchgear’s abilities to prevent phase-to-phase faults.
A new design for medium-voltage switchgear addresses these issues through an insulation system called shielded solid insulated switchgear. Rather than air separating each bus bar, a molded solid dielectric insulator acts as the source of dielectric strength.
One benefit is a significant reduction in footprint: solid insulation allows for a decreased air gap between phase conductors, reducing overall equipment size. Comparing traditional metal-clad switchgear to solid insulated switchgear, footprint can be reduced by as much as 60%. Additionally, decreased footprint allows for front-accessible switchgear design.
Switchgear can be placed against walls or pushed into electrical room corners. This is attractive for space-constrained facilities, or where dust, debris, or rodents are of concern. Protection from natural elements reduces maintenance intervals, with maintenance cycles of up to 10 years for solid insulated switchgear.
A standard of safety
Low maintenance is important given the entering workforce. With so many people just learning the equipment, less maintenance means less chance for human error. Reducing arc flash incidents is perhaps the greatest benefit of shielded solid insulated switchgear technology. By separating each phase with two insulating epoxy layers, two ground shields and an air gap, the probability of any kind of phase-to-phase interaction is minimized.
With shielded solid insulation switchgear every interior portion is at ground potential, minimizing phase-to-phase interaction, reducing arc flash likelihood, and protecting the insulating material.
Traditional metal-clad switchgear only offered 1200 amp and above ratings, whereas shielded solid insulation switchgears offer circuit breakers with ratings of 200 amp, 600 amp, and 1200 amp. Designers can select breakers that reflect the load requirements and reduce costs.
Shielded solid insulation increases reliability of medium-voltage switchgear, making it an easy choice in upgrades for oil & gas operators. As the industry faces budget cuts, worker retention issues, and stricter guidelines, innovative solutions are needed. Shielded solid insulation switchgear relieves budget concerns and constitutes a safe and reliable asset.
Joe Richard is U.S. launch manager for Schneider Electric medium voltage switchgear.