外文文献一General Requirements to Construction of SubstationSubstations are a vital element in a power supply system of industrial enterprisesThey serve to receive ，convert and distribute electric energy .Depending on power and purpose ,the substations are divided into central distribution substations for a voltage of 110-500kV;main step-down substations for110-220/6-10-35kV;deep entrance substations for 110-330/6-10Kv;distribution substations for 6-10Kv;shop transformer substations for 6-10/0
