Introduction on indian codes as applied in electrical design


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Introduction to Indian codes & regulation as applied in electrical design.
This PPT will provide information about role and utility of various codes being followed in India for electrical design
This PPT will also give sample details about lighting and grounding design

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Introduction on indian codes as applied in electrical design

  1. 1. Introduction on Indian codes &Introduction on Indian codes & regulation as applied in electricalregulation as applied in electrical designdesign ByBy Asif EqbalAsif Eqbal By Asif Eqbal
  2. 2. ContentContent Major codes & standard followed in India for electrical design Objective of codes & standard Indian Code for Industrial Lighting System Indian Code for Earthing System Indian Code for Lightning Protection System By Asif Eqbal
  3. 3. Major codes & standard followed inMajor codes & standard followed in IndiaIndia  Indian Electricity rules, 1956 as amended up to 25TH Nov., 2000  Bureau of Indian standards  Central electricity authority guidelines  CPCB norms (central pollution control board)  National building code  CBIP manuals (Central board of irrigation & power)  Oil Industry safety directorate (OISD) for oil & gas industry IE rules & IS takes precedence over all the standards. None of the Indian standard contradicts each other, they only supplement each other in a way that what is not mentioned in one standard is available in another. By Asif Eqbal
  4. 4. Indian Electricity RulesIndian Electricity Rules  Indian electricity rues are based on Indian Electricity Act,1910 recommended by Central Electricity Board of India.  IE rules are mandatory as they have been prepared and implemented by legislation of government of India.  All the statutory clearances and approval for any project is provided by central electrical inspector to that province where the location of project is and also the local provincial inspector. Central electrical inspector carries the inspection as per the guidelines of IS and IE rules.  IE rules defines the eligibility criteria for any person to operate or undertake maintenance of any type of industrial electrical installation. Major guidelines provided are as follows:  Clearance above ground of the lowest conductor.- No conductor of an overhead line, including service lines, erected across a street shall at any part thereof be at a height of less than- (a) for low and medium voltage lines 5.8 meters (b) for high voltage lines 6.1 meters By Asif Eqbal
  5. 5. Indian Electricity RulesIndian Electricity Rules No conductor of an overhead line including service lines, erected elsewhere than along or across any street shall be at a height less than -  for low, medium and high voltages lines up to and including 11,000 volts, if bare 4.6 meters  for low, medium and high voltage lines up to and including 11,000 volts, if insulated 4.0 meters  for high voltage lines above 11,000 volts 5.2 meters  For extra-high voltage lines the clearance above ground shall not be less than 5.2 meters plus 0.3 meter for every 33,000 volts or part thereof by which the voltage of the line exceeds 33,000 volts; Provided that the minimum clearance along or across any street shall not be less than 6.1 meters. By Asif Eqbal
  6. 6. Indian Electricity RulesIndian Electricity Rules  Routes; Proximity to aerodromes, Transporting and Storing of material near overhead lines are also defined in IE rules.  Other features and area covered by IE rules are: I. GENERAL SAFETY REQUIREMENTS II. Testing of consumer’s installation III. Installation and Testing of Generating Units IV. Test for resistance of insulation V. ELECTRIC TRACTION VI. ADDITIONAL PRECAUTIONS TO BE ADOPTED IN MINES AND OIL-FIELDS VII. Connection with earth & Earth leakage protective device VIII. Identification of earthed and earthed neutral conductors and IX. position of switches and cut-outs therein X. Earthed terminal on consumer’s premises XI. Accessibility of bare conductors 15 XII. Danger notices By Asif Eqbal
  7. 7. Indian Electricity RulesIndian Electricity Rules As per IE rules voltage are categorized as  “ low” where the voltage does not exceed 250 volts under normal conditions.  “medium "where the voltage does not exceed 650 volts under normal conditions.  “ high "where the voltage does not exceed 33,000 volts under normal conditions.  “ extra high "where the voltage exceeds 33,000 volts under normal conditions.  However as per general practice 415 and lesser is considered as low, above 415 and less than 33kV is considered as medium and 33kV and above is considered as high. Above 400kV is considered as EHV. By Asif Eqbal
  8. 8. Central Electricity authority (CEA)Central Electricity authority (CEA)  Standard Technical Specification for Sub- critical Thermal Power Project - 2x(500MW or above).  Because of unprecedented growth being witnessed by the power sector with a capacity addition of over 78,000 MW envisaged during 11th Plan and about 80,000 MW in 12th Plan, every possible opportunity for enhancing pace of capacity addition is explored and fully exploited. In this context, there has been a long felt need to standardize the technical specification of thermal power stations with a view to reducing the time for pre-award activities, design & engineering and the manufacturing by equipment manufacturers. To do this, a Committee was set up by CEA under the chairmanship of Member Thermal) in May 2007 with participation from major utilities and manufacturers for developing standard technical specifications for main plant equipment for coal based thermal power plant having 500MW and higher capacity sub-critical units. By Asif Eqbal
  9. 9. Central Electricity authority (CEA)Central Electricity authority (CEA)  This guideline covers the design, engineering, manufacture, inspection and testing at manufacturer's works, supply, packing and delivery at project site, unloading, storage and in plant transportation at site, erection, supervision, pre-commissioning, testing, successful commissioning, performance testing and handing over of main plant package for sub-critical thermal power project having two (2) units of 500 MW (or above) consisting of steam generator, steam turbine– generator, electrical system, and C&I system along with all associated auxiliaries and accessories and associated civil works.  These guidelines are framed by Government of India, Ministry of Power, New Delhi. By Asif Eqbal
  10. 10. Central Pollution Control Board NormsCentral Pollution Control Board Norms (CPB)(CPB)  The Central Pollution Control Board (CPCB), statutory organization, was constituted in September, 1974 under the Water (Prevention and Control of Pollution) Act, 1974. Further, CPCB was entrusted with the powers and functions under the Air (Prevention and Control of Pollution) Act, 1981.  CPCB norms are framed by ministry of environment.  Every industrial installation requires to get the clearance from CPCB before being commissioned.  In electrical industry/installation the most widely and important CPCB norm is installation and exhaust of emergency diesel generator.  Stack height for exhaust gases from diesel generator as per CPCB norm is given by the following formula: H = h + 0.2(kVA)0.5 H = Height of stack h = Height of building in meter where DG is installed. kVA = Total electrical power output of diesel generator. By Asif Eqbal
  11. 11. Central Pollution Control Board NormsCentral Pollution Control Board Norms (CPB)(CPB)  The stack height was originally evolved for those to be evolved in metropolitan areas of Delhi.  The idea was to avoid the problem of road side discharge from stack and built up of pollutants in ambient air.  For factories set up away from metropolis which use the emergency diesel set occasionally are given some relaxation with respect to height of stack . Hence for non residential and commercial area the height of stack as per CPCB should be 2.5 times the height of building where DG set is installed or height of that building within factory premises where people are working.  CPCB norms also specifies the emission norms for diesel engine rating more than 800kW for power plant generator set application and other requirements. By Asif Eqbal
  12. 12. National Building codeNational Building code  National building code is the prime code applicable for commercial buildings.  The National Building Code of India (NBC), a comprehensive building Code, is a national instrument providing guidelines for regulating the building construction activities across the country. It serves as a Model Code for adoption by all agencies involved in building construction works be they Public Works Departments, other government construction departments, local bodies or private construction agencies. The Code was first published in 1970 at the instance of Planning Commission and then revised in 1983. Thereafter three major amendments were issued, two in 1987 and the third in 1997. By Asif Eqbal
  13. 13. National Building codeNational Building code  All the wiring installations for lighting and power receptacles are carried out as per the NBC guidelines and IS 732.  The Code mainly contains administrative regulations, development control rules and general building requirements; fire safety requirements; stipulations regarding materials, structural design and construction (including safety); and building and plumbing services general requirements of telecommunication, fire safety, earthing and lightning protection and earthing for high rise buildings (Apartments, shopping malls, hotels and official complexes) is also covered in this code. By Asif Eqbal
  14. 14. Central Board of Irrigation &Central Board of Irrigation & Power (CBIP)Power (CBIP)  Central Board of Irrigation & Power (CBIP), a Premier Institution, rendering dedicated services to professional organizations, engineers and individuals for more than 81 years, resulting in accelerated development in Water Resources, Energy and Allied Fields, including renewable energy, in the country and abroad. CBIP has grown into an eminent organization of international importance while serving the nation equally with great distinction. CBIP is Indian chapter for 10 international organizations related to aforesaid sector.  Today, Central Board of Irrigation and Power presents a shining example of a pioneer organization and has enabled Indian industry to set higher benchmarks and attain international standards in excellence by creating a unique platform for growth and progress of these sector.  Some important features of CBIP norms are that lot of figures are clearly mentioned in this code which are not mentioned in any other Indian codes. Some examples are: Loss figure for oil type power & distribution transformer By Asif Eqbal
  15. 15. Central Board of Irrigation &Central Board of Irrigation & Power (CBIP)Power (CBIP)  Loss figure for oil type power & distribution transformer  Standard ratings for bus ducts at various voltage level  Complete step by step procedure for S/S earthing  Earthing and transformers are the two electrical package where the CBIP manuals are widely used. IS 3043 is supplemented by this standard as IS does not mentions details about earth mat design for switchyard or S/S.  IS for power transformer is also supplemented by this standard as none of the IS mentions the loss figure, relation between ONAN and ONAF rating over fluxing capability etc…..for any transformer. By Asif Eqbal
  16. 16. Objectives of codes & standardObjectives of codes & standard  The Electrical System shall be designed to provide:  Safety to personnel and equipment both during operation and maintenance.  Reliability of Service.  Minimum fire risk.  Ease of maintenance and convenience of operation.  Automatic protection of all electrical equipment through selective relaying system.  Electrical supply to equipment and machinery within the design operating limits.  Adequate provision for future extension and modification.  Cost effective. By Asif Eqbal
  17. 17. Objectives of codes & standardObjectives of codes & standard  The design shall be in accordance with established codes, Standards, Specifications, sound engineering practices and shall conform to the statutory regulations applicable in India and at Site Location. In case of conflict in the various documents and drawings and various Codes and Standards followed, the most stringent shall govern. By Asif Eqbal
  18. 18. Indian Code for Industrial LightingIndian Code for Industrial Lighting SystemSystem  IS 3646 : CODE OF PRACTICE FOR INTERIOR ILLUMINATION  IS 6665 : CODE OF PRACTICE FOR INDUSTRIAL LIGHTING By Asif Eqbal
  19. 19. Design GuidelinesDesign Guidelines  Plant Illumination System comprise of following:  Normal 230V, ac lighting system.  Normal-cum-emergency 230 V, ac lighting system having DG backup.  Critical DC Lighting having DC Battery backup.  20-25% of total Plant Lighting should be emergency lighting having DG Back-up.  Critical Areas of Plant such as sub-station, control room, exit points should have critical DC Lighting having DC battery backup.  During normal operation, normal & emergency lighting fed by normal power source.  On failure of normal supply, emergency lighting load shall transfer to emergency source. By Asif Eqbal
  20. 20. Design GuidelinesDesign Guidelines  Illuminance ranges recommended for interior or activity : • Middle value (R) for working interiors • Higher value (H) for visual work • Lower value (L) where accuracy is non-important By Asif Eqbal
  22. 22. Type of Lighting SystemType of Lighting System Type of Lamp Lum / Watt Color Rendering Index Typical Application Life (Hours) Range Avg. Incandescent 8-18 14 Excellent Homes, restaurants, general lighting, emergency lighting 1000 Fluorescent Lamps 46-60 50 Good w.r.t. coating Offices, shops, hospitals, homes 5000 Compact fluorescent lamps (CFL) 40-70 60 Very good Hotels, shops, homes, offices 8000-10000 High pressure mercury (HPMV) 44-57 50 Fair General lighting in factories, garages, car parking, flood lighting 5000 High pressure sodium (HPSV) SON 67-121 90 Fair General lighting in factories, ware houses, street lighting 6000-12000 Low pressure sodium (LPSV) SOX 101- 175 150 Poor Roadways, tunnels, canals, street lighting 6000-12000 By Asif Eqbal
  23. 23. Lighting CalculationLighting Calculation  Dia-LUX is a 3D-software used for effective and professional light planning.  It is possible to import CAD model of Architectural Building and plan lighting arrangement on exact location as desired and perform Lighting Calculation to achieve desired Illumination Level on work-plane area.  Dia-LUX can be used for planning of Indoor Lighting, Exterior Lighting and street lighting.  It issue normative documentation to validate the design. By Asif Eqbal
  24. 24. Indian Code for Earthing/GroundingIndian Code for Earthing/Grounding SystemSystem  IS 3043 : CODE OF PRACTICE FOR EARTHING By Asif Eqbal
  25. 25. Design GuidelinesDesign Guidelines  The earthing system shall be provided for;  Equipment earthing for personnel safety  System neutral earthing  Static earthing  Protection against lightning  The earthing conductor shall be adequately sized to carry the maximum earth fault current. Earth resistance shall be less than 1 ohm. The number and depth to which the electrodes are driven depend upon soil condition s and soil electrical resistivity levels.  All medium voltage equipment shall be earthed by two separate and distinct connections with earth.  In case of High and extra high voltage, the neutral point shall be earthed by not less than two separate and distinct connections with earth, each having its own electrode at the sub-station. By Asif Eqbal
  26. 26. Design GuidelinesDesign Guidelines  Main switchboards and MCCs shall be provided with an earth bar running the full length of the board, which shall be connected to sub-station main earthing grid.  Separate clean earth system for instrumentation, DCS, PLC etc shall be provided as required.  A separate earth conductor shall be laid along the cable trays and all other trays shall be interconnected at every 10m distance.  Lighting fixtures, receptacles, switches, conduits and junction boxes shall be properly earthed using 12 SWG GI wire run along the entire length of the conduit. By Asif Eqbal
  27. 27. Earthing CalculationEarthing Calculation Step-1 To Determine minimum size of Earth Conductor (As per IS:3043) S = I√t k Where, S = Conductor cross section area in mm² I = Fault current in amperes. t = Fault duration in seconds k = Constant depending on material of earthing conductor, its insulation, the initial and final temperature. Step-2 Calculate Resistance of Earth Electrode (As per IS:3043) Re = (100 X ρ X Ln (4L/D)) 2ΠL Where, Re = Resistance of earth electrode L = Length of pipe in cm ρ = soil resistivity in ohm-m D = Diameter of pipe in cm By Asif Eqbal
  28. 28. Earthing CalculationEarthing Calculation Step-3 Calculate Net Resistance of Earth Electrode (As per IS:3043) Rearth = Re N Where, Rearth = Net resistance of Earth Pits Re = Resistance of Pipe Electrode N = No. of Earth Electrode considered Step-4 Calculate Resistance of Earth Strip (As per IS:3043) Rs = (100 X ρ X Ln (2L2 /(wXt))) 2ΠL Where, RS = Resistance of earth strip L = Length of conductor in cm. w = Depth of burial of electrode in cm t = width of the electrode in cm or twice the diameter of conductor in cm. By Asif Eqbal
  29. 29. Earthing CalculationEarthing Calculation Step-5 Calculate Total Grid Resistance (As per IS:3043) RTotal = Rearth X Rs Rearth + Rs Where, Rearth = Net resistance of Earth Pits Rs = Resistance of Earth Strip RTotal = Total Grid Resistance By Asif Eqbal
  31. 31. Design GuidelinesDesign Guidelines  Lightning is a natural hazard, being the discharge of static electricity generated in storm clouds, which may cause damage to structures.  The need for providing the lightning protection system shall be established by calculating risk index value for each building structure etc as per procedure give in IS: 2309 and any building whose overall risk factor is more than 10-5 shall be provided with lightning protection.  Lightning protection system shall consist of vertical air termination roads, horizontal roof conductors, down conductors and earth electrodes.  Air termination and down conductors for buildings shall be of GS flat. Electrodes shall be GS rod.  Each down conductor shall be connected to a rod electrode, which in turn shall be connected to the station earthing system through test links.  Conductors of lightning protection system shall not be connected with conductors of safety earthing system above ground level. By Asif Eqbal
  32. 32. Design GuidelinesDesign Guidelines  Galvanized Steel (GS) is used as the material for lightning protection conductor.  The sizes of the conductors for lightning protection system are decided based on mechanical strength. The minimum size for air terminations and down conductor, as per IS-2309, table-4 is 20X3 mm GS. However, higher size is selected considering mechanical strength.  Air termination network may consist of vertical or horizontal conductors or combination of both which is provided for the buildings requiring lightning protection according to IS : 2309.  Down conductors shall be as short and straight as practicable and shall follow a direct path to earth electrode.  As per IS 2309, article no. 12.2.5, Steel column can be acted as Down Conductor and as per IS 2309, article no. 9.0.1, Metal roof can be acted as Air termination. By Asif Eqbal