Internal arc based innovation for medium voltage switchgear

The market requirements for Medium Voltage (MV) metal enclosed switchgear are getting more and more stringent. Both building costs as well as the level of the transmitted and distributed electrical power have increased rapidly over the recent years and are expected to continue to rise. This means that switchgear manufacturers must bring more and more compact and powerful systems on the market, while being simultaneously as cost effective as possible. However, because of the strong competition, the development time and costs available for designers are being reduced from year to year. This makes the task extremely difficult forcing the developer to pursue new directions in product development. This paper describes a new development path, so-called “internal arc based” as well as the successful qualification of the switchgear “GMA Efficient” (gas insulated switchgear) in accordance with the applicable IEC standard and in compliance with the above mentioned requirements. It also describes a few important design rules and innovations, which were necessary to achieve this result. Furthermore it demonstrates how expertise and numerical analysis throughout the development phase are critical to the success of a cost, size and performance optimized switchgear design.