GAIL (India) Limited

91 Scope:CHAPTER 2POWER CONTROL CENTRES / POWER DISTRIBUTION BOARDS / MOTORCONTROL CENTRES.This specification is to cover the requirement of design, supply, installation, testing and commissioning ofLT power control centres / main switchboards with all components. Instruments, fittings and accessoriesfor efficient operation without any trouble.NOTE : THE MAIN CABLE SHALL RUN FROM THE SPARE FEEDER IN EXISTINGSUBSTATION TO THE PROPOSED OFFICE BUILDING.2. Standards:The PCC (Power Control Centre) / PDB/ MCC specified herein unless otherwise stated shall conform tothe relevant and latest revisions of Indian standards and Indian Electricity Rules.3. Design and construction:3.1 Design requirements: The power control centres shall be suitable for operation on 440volt, 3 phase,4wire 50 HZ system to withstand a short circuit level of 50 KA RMS symmetrical.The PCC (Power Control Centre) shall be designed for operation in high ambient temperature up to 45degrees centigrade and high humidity up to 95% and tropical atmospheric conditions. Means shall beprovided to facilitate ease of inspection. Maintenance and Servicing.3.2 Constructional requirements:The PCC (Power Control Centre) shall be ofi. Metal clad, cubicle, indoor, free standing type suitable for Mounting on Built up Trenches with UChannels of adequate size.ii. Made up of the requisite vertical sections, which when coupled together shall form continuousdead front switchboard.iii. Dust and damp protected the degree of protection shall be better than IP - 54 as specified in IS-2147.iv. Readily extendable on both sides by the addition of vertical sections after removal of the endcovers.v. Single front construction with the circuit beaker feeder and switch fuse feeders suitable foroperation from the front of the panel.The PCC (Power Control Centre) shall have the feeder ratings as per the schematic diagrams enclosedwith the schedule and constructed only of materials capable of withstanding the mechanical, electrical andthermal stresses as well as the effects of humidify, which are likely to be encountered in normal service.3.3 Vertical Sections each vertical section shall comprise a front framed structure rolled folded sheet steelchannel section of minimum 2mm thickness rigidly bolted together. This structure shall house thecomponents contributing the major weight of the equipment such as circuit breaker, switch fuse units,main horizontal bus bars, vertical risers and other front mounted accessories The structure shall bemounted on a rigid base frame of folded sheet steel of minimum of 2.5 mm thickness and 100mm height.The design shall ensure Structural stability during Transit and also during Operation after CommissioningSuitable cable chamber housing the cable end connections and power / control cable terminations shall beprovided The design shall ensure generous availability of space for ease of installation and maintenance ofcabling and adequate safety for working in one vertical section without coming into accidental contactwith live parts in the adjacent section