Indoor substations are generally used for power distribution at lower voltage levels of 33/11/6.6kV. Transformers are located outside and all switchgears are mounted inside substation building. The cabling between various equipment is done either in cable trenches or in cable spreader rooms below the switchgear room. Because of indoor design, maintenance of equipment is easier.
Electrical power distribution system for various industries comprises of HV/LV Switchgears, MCCs, LT Transformers, HT/LT Bus ducts, Cabling upto motors and other power consuming equipment like heaters, furnaces, boilers, air conditioners, lighting, UPS etc., field switches, instrumentation, electrical interlocks through PLC, lighting, earthing and lightning protection of all plant buildings and equipment. Plant control is generally through PLC HMI.
Huge network of HV & LV Power cables are required in large industries to interconnect HV and LV electrical equipment among themselves. These cables are selected based on magnitude of power flow and their short circuit withstand. Control cables connect various actuating devices with their remote control points and provides status feedback from field devices. Extensive amount of engineering is involved in selecting the cable types, length estimations, their routes and method of laying. Cables can be laid in trenches, cable tunnels, cable overhead bridges or directly buried underground based on application.