The Siemens Low and Medium Voltage Division has developed a new gas-insulated medium-voltage switchgear, 8DJH Compact, for secondary distribution systems up to 24 kV. This type-tested switchgear, which conforms to IEC 62271-200, is about a third smaller in size than a comparable model. New urban local transformer substations, for example, can now be built on a smaller scale and therefore at lower cost using 8DJH Compact.
The new switchgear is especially suitable for modernizing existing compact substations, as well as for intelligent local transformer substations being components of Smart Grids. The extra space made available can be used for additional low-voltage feeders, medium-voltage feeders, or Smart Grid functionalities such as integration of monitoring systems or telecontrol units. The new 8DJH Compact is maintenance-free, resulting in reduced operating costs.
Factory-assembled, type-tested 8DJH Compact is a three-pole metal-enclosed, single-busbar switchgear designed for indoor installation, and providing all the functionalities of other switchgear in the 8DJH product family. The medium voltage switchgear is used in public and industrial power systems of the secondary distribution level, for example in local transformer substations of power supply companies, or in medium-voltage infeeds of infrastructure projects. The delivery portfolio ranges from the panel block with two ring-main feeders (630 A) and one transformer feeder (200 A), the so-called RRT scheme, to the double panel block RRT-RRT with 1,400 mm or 1,700 mm height.
Transformer cables are optionally connected from the rear, from the top, or from the side. Shorter transformer cables and reduced expenses for laying these cables inside the compact substation are added advantages, and reduce investment costs. The switchgear offers a high level of protection for personnel and equipment as a result of internal arcing tests in accordance with the latest standard IEC/EN 62271-200. Switchgear vessels designed as a hermetically sealed pressure system, with maintenance-free switching devices and enclosed cable plugs, ensure maximum supply reliability, independence from environmental conditions, and reduced operating costs since no maintenance cycles are necessary