Switzerland-based transmission and distribution component specialist PFIFFNER Group has announced a new, high voltage air-insulated switchgear (AIS) circuit breaker for substations which uses an SF6-free and F-gas free as its insulation media, helping to set a new standard for the safe and sustainable operation of electrical grids. 

The circuit breaker, currently in the development stage, will complement the company’s growing portfolio of high voltage solutions while helping customers to reduce their carbon footprint in a cost-effective way.

Sulfur hexafluoride, commonly known as SF6, is a man-made gas utilized primarily as an electrical insulator and arc suppressant. While extremely effective in circuit breaker applications, it is also one of the most harmful greenhouse gases in existence. As such, component manufacturers in the electrical grid sector have been seeking solutions in recent years to limit its usage. PFIFFNER‘s solution instead uses an eco-compatible gas that eliminates the use of SF6 and F-gases entirely.

Circuit breakers are one of the most critical components in an AIS switchyard. Reliability is crucial, as the product has to work under all conditions, and may spend many years or decades at a time dormant before being required to spring into action. When closed, the circuit breaker must behave like an ideal conductor with no resistance, and when open it must be a perfect insulator, conducting nothing. When the contacts separate upon activation, the interrupter must move instantly to extinguish any arcing and prevent damage to downstream line components. When activated this process will typically occur within 20 to 30 milliseconds, involving the high-speed movement of mechanical masses up to 20-30 kg. 

PFIFFNER’s Team Lead on the development of the circuit breaker explained some of the technical challenges involved: “Arcs can get extremely hot, upwards of 25,000 K, and a large concentration of gas must be forced into the area between the contacts at high speed to extinguish the arc and thus, interrupt the current. As such, components must meet stringent performance and reliability standards to ensure safety and efficacy.

“The industry has been aware of the issues of working with SF6 for many years, however, alternatives, that can match its performance have been difficult to find. With this new circuit breaker, we believe we have found a solution that delivers on sustainability without compromising performance or safety, by means of the application of innovative concepts.”

For Dr. Juergen Bernauer, CEO, PFIFFNER Group, the new circuit breaker builds upon the company’s well-established core values of quality, transparency and trust: “As a Swiss company we take enormous pride in our heritage, and as a family-owned company that is accountable to customers rather than shareholders, we have the agility to respond quickly to market trends. The new circuit breaker is an excellent example of innovation coming together with sustainability to create a new, ground-breaking solution that helps to improve performance while also making a positive difference for the planet.

“We have a strong focus on self-sufficiency; we try and produce as much as we can by ourselves, keeping as much expertise and value-adding services in-house as possible. This reduces our reliance on external supply chains while allowing us to utilize the expertise of our engineers precisely when and where our customers need it. This project for example has required a range of different disciplines, from mechanical and electrical to analytics and even fluid dynamics, demonstrating the versatility of our company’s skills base, and the agility with which we can deploy it. I am delighted to announce that we are extending our already impressive portfolio with such an innovative product and am eager to see the positive impact it has with our customers when it is launched.”