Switchgears and controlgears are important nodal points in modern power systems, and are used in a variety of applications. The terms, defined by EN IEC 60947, indicate electrical disconnect switches, fuses, and circuit breakers used to control, protect and isolate electrical equipment, in order to ensure safety for electrical infrastructures and the individuals using them.
A variety of techniques have been developed to isolate electric gears, using different insulation materials, from simple air to oil or gases. One of the most advanced – and secure – mechanisms consists of using gas SF6: in this solution, high voltage conductors, circuit breaker interrupters, switches, current transformers, and voltage transformers are immersed in gas inside grounded metal enclosures, so-called gas-insulated substations (GIS).
Recently updated European standard EN 50068:2018 ‘High-Voltage Switchgear and Controlgear - Gas-filled wrought steel enclosures’ is dedicated to ensure a high level of safety in these infrastructures. The standard applies to a specific kind of GIS, welded wrought steel enclosures pressurised with inert gases, used for insulation in installations of high-voltage switchgear and controlgear with rated voltages above 1kV, where the gas used is chosen principally for its dielectric properties.
EN 50068 is the iteration of a widely used standard, first introduced in 1991. It introduces some updates, which were made necessary to account for technological developments. In particular, the standard establishes consistent requirements all across Europe for the design, construction, testing, inspection and certification of pressurised enclosures used in HV switchgear and controlgear, based on Article 2 of Directive 2014/68/EU, also known as ‘Pressure Equipment Directive’. The standard addresses the specific requirements of the European industry, helping it compete and reduce the barriers to trade within the Single Market.
EN 50068 has been published by CLC/TC 17AC, whose Secretariat is held by DKE, the German National Electrotechnical Standardization Board.
For more information, please contact Constant Kohler