Distribution Inside Large Buildings In large buildings the type of distribution depends on the building type, dimension, the length of supply cables, and the loads. The distribution system can be divided in to: ď ś The vertical supply system (rising mains). ď ś The horizontal supply (distribution at each floor level). In most cases a high voltage supply and transformer substation is required. Normally HV switchgear and substation transformers are installed at ground floor ( or basement ). However, often there are appliances with large power demand installed on the top floors (converters and motors for lifts, airconditioning equipment and electric kitchens). As it is desirable to brining the high voltage supply as close as possible to the load centers, transformers are installed at the top floor, or if required, additional ones are installed on one of the intermediate floors. In such cases transformers with non-inflammable insulation and cooling are used. The arrangement of the rising mains depends on the size and shape of the building and suitable size of shafts for installing cables and bus ducts must be provided in coordination with the building architect. The vertical supply system are implemented in several ways, some of which are :
Department of Electrical Engineering – Dr. Hussain Al-Mashat
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