At the heart of SF₆-free switchgear: Sarah Kilian and the power of vacuum interrupters

When powerful electrical arcs flash across a high-voltage test field and thunder-like bursts fill the air, most people instinctively step back. Sarah Kilian remains focused. For the Siemens Energy engineer, these moments are not extraordinary. They are part of the work of developing technologies that help make tomorrow's power grids more reliable, resilient, and sustainable. 

Even during her physics studies, Sarah Kilian was fascinated by the connection between scientific principles and practical applications. Rather than focusing solely on theory, she wanted to build technologies that solve tangible challenges.

Alongside her studies, she joined a Berlin-based start-up, where she worked closely with major customers and assumed significant responsibility early in her career. After nearly a decade, she was ready for a new challenge. She found it at Siemens Energy. The opportunity to work on high-voltage switching technology offered exactly what she was looking for: the chance to develop innovative ideas, validate them through testing, and help bring new technologies from concept to implementation.

Moving from a small company to a global organization represented a major shift. Cross-functional projects, international collaboration, and multiple stakeholders replaced the short decision-making paths she had known before. Yet curiosity outweighed uncertainty. From her first day, Sarah became part of a major development initiative, the 420-kV Blue gas-insulated switchgear project, which would shape much of her early career at Siemens Energy. 

Although rarely visible to the public, high-voltage circuit breakers play a critical role in modern power systems. They help keep electricity networks safe and stable by isolating sections of the grid during maintenance or faults, protecting equipment, supporting grid reliability, and enabling safe working conditions. "To turn on a light switch, we need this technology working behind the scenes", Sarah explains.

Many of the lessons learned during testing contributed directly to the development of Siemens Energy's 420-kV technology.

The project represents an important step toward more sustainable power transmission infrastructure. Its objective is to develop high-voltage switchgear that does not require SF₆, a greenhouse gas traditionally used in electrical equipment. By combining vacuum switching technology with clean-air insulation, Siemens Energy is advancing a more environmentally friendly solution for extra-high-voltage applications. 

Innovation in the energy sector rarely happens through a single breakthrough. Instead, progress is built through continuous learning, experimentation, and teamwork.

Away from laboratories, test equipment, and high-voltage systems, Sarah finds balance in nature. One of her most unexpected passions is beekeeping, a hobby that offers a welcome contrast to her highly technical work. 

While beekeeping and high-voltage engineering may seem worlds apart, both require patience, observation, and a long-term perspective. These qualities continue to shape Sarah's approach to innovation, leadership, and personal growth.