standards / manuals / guidelines for small hydro development - AHEC

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Bending .. .. 1265 kg/sq.cm.Shear .. .. 1265 kg/sq.cm.b) for concrete – 1 : 2 : 4Bending .. .. 52.7 kg/sq.cm.Shear .. .. 5.27 kg/sq.cm.Bend .. .. 7.03 kg/sq.cm.2.7.3 Factor of SafetyIndian Adopted by (TNEB)ElectricityRulesa. Fopr steel 2.0 2.5 based on maximumloading conditions (onelastic limit for tensionmembers and cripplingload for compressionmembers).b. For R. C. 2.5 3.5 on ultimate breakingc. For hand 3.0loadMoulded R. C.RecommendedAs per TNEBPracticeFactory of safety against overturning:a) Steel 2.5b) R. C. 2.02.7.4 Slenderness Ratio (L/R)Ratio of unsupported length (l) to radius of gyration (r) should not exceed;a) 140 for leg membersb) 200 for other members having calculated stresses only and 250 for membershaving nominal stress only.2.7.5 Minimum Thickness for Steel Members2.7.6 MaterialSteel employed for structures – open hearth steel with a high yield point and an ultimatestrength of not than 3867 kg/sq.cm.The following maximum stresses in lbs. per square inch are assumed for outdoorstructures, fabricated out of steel sections manufactured in India;1-15
i. Tension 18,000ii. Compression 18,000 – 76 l/r where l/r is less than 150 and 13,000 – 48l/r where l/r is more than 150iii. Shear on 13,500boltsiv. Bearing on 27,000bolts2.8 GIS SubstationsAdvancement in the use of SF6 as an insulating and interrupting medium have resulted inthe development of gas insulated substations. Environment and/or space limitations mayrequire the consideration of GIS (gas insulated substation) equipment. This equipmentutilizes SF6 as an insulating and interrupting medium and permits very compactinstallations. GIS substation are preferable to air insulated system ((AIS) because offollowing reasons:i) Compact design reduces space requirementsii) Higher reliabilityiii) Life cycle costs and safety are better because GIS is maintenance freeiv) Location advantage especially in areas (town) where space costs are highv) Environmental advantage as rain, dust, snow, ice, salt etc. do not affect thehermetically sealed metal clad GISThree-phase or single-phase bus configurations are normally available up to 145 kVclass, and single phase bus to 500 kV and higher, and all equipment (disconnect/isolatingswitches, grounding switches, circuit breakers, metering current, and potentialtransformers, etc.) are enclosed within an atmosphere of SF6 insulating gas. The superiorinsulating properties of SF6 allow very compact installations.GIS installations are also used in contaminated environments and as a means of deterringanimal intrusions. Although initial costs are higher than conventional substations, asmaller substation footprint can offset the increased initial costs by reducing the land areanecessary for the substation.2.8.1 GIS Compact SwitchgearCompact sub-station with gas insulated switchgear may be considered in following cases.i) Installations in areas with high risk of pollution and corrosion from industrialplants or by marine and desert climates.ii) Applications involving use of metal clad switchgear with components ofconventional design to minimize area requirement.iii) Underground substationsiv) Outdoor installation where space is not easily available1-16
Page 2 and 3: Section -1Guide for Design of Outdo
Page 4 and 5: The terms atmospheric overvoltages
Page 6 and 7: Table 2.31. Basic Data Example 1.Hi
Page 8 and 9: Spark gaps specified for fitting to
Page 10 and 11: 2.4.2 Working Safety Clearances125
Page 12 and 13: Highest System Voltage rating kV Sp
Page 14 and 15: 2.6 Insulator TypeTypes of insulato
Page 18 and 19: v) Installations in difficult site
Page 20 and 21: During maintenance, it is essential
Page 22 and 23: Areva Compact Air Insulated Substat
Page 24 and 25: The bus bar sizes should meet the e
Page 26 and 27: disconnect switch contacts in such
Page 28 and 29: (iv)Electro magnetic type interlock
Page 30 and 31: ) Temperature rise of 11 kV Class C
Page 32 and 33: 4.6 TestsThe CTs shall be provided
Page 34 and 35: 10. 1.2/50 micro seconds impulse 32
Page 36: 7.0 Lightning ArrestorsLightning ar
Page 39 and 40: and this aspect has to be kept in m
Page 41 and 42: Fig. 12.1: Layout of 12 kV Agnoor S
Page 43 and 44: Fig. 12.4 Layout of 72.5 kV Switchy
Page 45 and 46: 464006800 7600 3000LA30002000 2000X
Page 47 and 48: Fig. 12.6:145 kV Outdoor Switchyard
Page 49 and 50: Fig. 12.7: 245 kV Outdoor Switchyar
Page 51 and 52: 2-20
Page 53 and 54: 3.0 Transformer RatingThe full load
Page 55 and 56: OFAFOil Immersed with forced oil ci
Page 57 and 58: The transformer may be operated wit
Page 59 and 60: 8.10 Parallel OperationThe transfor
Page 61 and 62: (a)(b)33 kV Transformers (MVA)1.001
Page 63 and 64: (e)(f)(g)(h)(i)(j)(k)(l)(m)(n)(o)(p
Page 65 and 66: 18.0 Oil Containment and Fire Prote
Page 67 and 68:
) The limits of temperature rise me
Page 69 and 70:
Example Calculation -1Generator Tra
Page 71 and 72:
TRANSFORMER RATING AND CHARACTERSTI
Page 73 and 74:
3.0 Type of Circuit BreakerFollowin
Page 75 and 76:
iii) during arcing of SF6 breaker,
Page 77 and 78:
3.4 Protection Classes for Switchge
Page 79 and 80:
The rated voltage is expressed in k
Page 81 and 82:
5.7 Rated Short Circuit Making Curr
Page 83 and 84:
Effect of circuit conditions on rec
Page 85 and 86:
5.17 Rated time quantities and oper
Page 87 and 88:
25405017.5 812.516254024 812.516254
Page 89 and 90:
component of fault current in addit
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Steps involved in applying method a
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to earthxvii. Difference in the ins
Page 95 and 96:
Datai) Sub transient reactance of g
Page 97 and 98:
Annexure-1Current waveAA = envelop
Page 99:
Annexure-3Fig. 3.3 Arc extinction4-
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