Minimum Clearance in Substation: Voltage Highest Voltage 12KV 36KV 145KV 650 950 220KV 400KV 245KV 1050420KV 1425 1050(P-E) 1.900 3.400 1.900 4.200 4.300 6.400 5.500 8.000 1.100 1.900 1.100 1.900 2.700 4.300 4.600 5.500 Lighting Impulse Level (Kvp) 70 170 550 132KV Switching Impulse Level (Kvp) Minimum Clearance PhaseEarth 0.178 0.320 1.100 PhasePhase 0.229 0.320 1.100 Safety Ground Clearance(Mt) Clearance(Mt) 2.600 2.800 3.700 3.700 3.700 4.600 11KV 33KV Electrical Clearance in Substation: Height of Earth Height of I II Bay Wire Phase-Phase Bay Width (Mt) BetweenEquipment Bay From From From (Mt) Ground (Mt) Ground Ground (Mt) 8.0 12.5 18.5 15.6 25 22 11.0 18 25 22.0 3.0 4.5 4.5 7.0 3.0 4.5 4.5 >6.0 10.5 15.5 28.5 30.0 Voltage 132KV (Single) 220KV (Single) 220KV (Double) 400KV Standard Bay Widths in Meters: Voltage 11KV 33KV 66KV 132KV 220KV 400KV Bay Width (Meter) 4.7 Meter 4.7 Meter 7.6 Meter 12.2 Meter 17 Meter 27 Meter Standard Bus and Equipment Elevation Voltage Equipment live Terminal Elevation (Meter) 2.8 To 4 2.8 To 4 3.7 To5 4.9 To5.5 8.0 Main Bus Low 5.5 To 6.5 6 To 8 8 To 9.5 9To13 15.5 High 9 9To 10.5 13.5To14.5 18.5 Take of Elevation (Meter) 6.5To8.5 9.5 12To12.5 15To18.5 23 11 KV/33KV 66KV 132KV 220KV 400KV 000 Section Clearance (Mt) 2.600 2.Phase spacing for strung Bus: Voltage 11KV 33KV 66KV 132KV 220KV 400KV Clearance 1300 mm 1300 mm 2200 mm 3000 mm 4500 mm 7000 mm Minimum Clearance of Live Parts from Ground: Voltage 11KV 33KV 66KV 132KV 220KV 400KV Minimum Clearance to Ground (Mt) 3.4 .000 Insulator String: Voltage 66KV 132KV 220KV 400KV Nominal Span: Voltage 66KV 132KV 220KV 400KV Normal Span (Meter) 240-250-275 315-325-335 315-325-335 315-325-335 No of Suspension String 5 9 14 23 Length (mm) 965 1255 1915 3850 No of Disc for Tension String 6 10 15 2 X 23 Length in (mm) 1070 1820 2915 5450 Minimum Ground Clearance: Voltage 66KV 132KV 220KV 400KV 800KV Ground (Meter) 5.0 12.500 8.600 5.5 6.600 4.700 3.700 4.000 3.500 4.0 8.1 7.800 3.300 7. Buchholz.140 4.Buchholz.88 2.03 1.A (From T. High set) +1 directional E/L dir.2 Meter Descriptions Horizontally between any item of equipment and thesubstation wall Horizontally between any Two items of equipment Horizontally in front of any HV switchgear Clearance of Conductor on Tower Voltage 66KV Tower Type A B C 132KV A B C D 220KV A B C D NORMS OF PROTECTION FOR EHV CLASS POWER TRANSFORMERS Voltage ratio & capacity HV Side LV Side 2 O/L relays + 1 E/L relay Common relays Buchholz.68 132/33/11KV up to 8 3 O/L relays + 1 E/L relay MVA 132/33/11KV above 8 MVA and below 31. WT Differential.6 Total Height From Ground(Mt) 15. Location of L.27 4.14 22.42 16. OLTCPRV.5 10.2 5. WT Vertical Space (Mt) 1. 31. OLTCBuchholz. Restricted E/F relay (alarm) relay Directional O/L relays for action The bottom most portion of any insulator or bushing in service should be at a minimum height of 2500 mm above ground level.25 6. E/L relay 100 MVA 400/220KV 315MVA 3 O/L relays + 1 E/L relay 3 O/L relays + 1 dir. E/L relay 3 O/L relays + 1 E/L relay 132/33KV.5 MVA 3 O/L relays + 1 dir. WT Differential.06 22.06 28. WT Differential. 31.08 31. Restricted E/F relay + 3 relays.5MVA & 50MVA 220/132KV.C Bushing): Voltage 11KV 33KV 66KV 132KV BIL KV Peak 75 200 325 550 Distance (Mt) 12 15 24 35 . Over flux.2 5. OLTCBuchholz. WT and overload relays.2 4.24 23. Over flux.9 Meter 0.22 7. OT.15 8.29 7. E/L relay & above 220/33 KV.17 6.6 Meter 1.7 Horizontal Space(Mt) 4.Buchholz. OT. OT.5 MVA 3 O/L relays + 1 dir.Indoor Substation Minimum Clearances Distance 0.Buchholz.0 4. High set)+1 directional E/L OLTCPRV.2 4.55 29. OT. Over flux. dir. OT.5 12. OLTCPRV. relay 3 directional O/L relays (with 3 directional O/L relays (with Differential.03 1.68 24. 3 O/L relays + 1 dir.8 8.91 15. 2 2057.4 Minimum Working Clearance: OUTDOOR SWITCHYARD Voltage in KV 11 33 66 132 220 To ground in mm 2750 3700 4000 4600 5500 Between section in mm 2500 2800 3000 3500 4500 Minimum Ground Clearance As Per IE-1957 (Rule 77) Voltage in KV To ground in mm .8 1778 Phase to phase in mm 177.5 76.05 50.8 863.6 139.9 127.2 101.05 50.8 63. INDOOR Voltage in KV 0.6 1219.8 279.8 228.6 11 15 22 33 Phase to earth in mm 15.6 11 22 33 66 110 132 220 Phase to earth in mm 139.600 3.8 19.25 Phase to phase in mm 19.220KV 400KV 900 To 1050 Close To T.3 355.1 241.3 6.C 1425 To 1550 Minimum Electrical Clearance As Per BS:162.2 431.6 Minimum Electrical Clearance As Per BS:162.8 787.6 330.7 222. OUTDOOR Voltage in KV 6.8 88.415 0.7 177.0 165.4 990.05 19.6 1066.4 381 685. 94 7.58 4.6 3.10 7.94 7.94 800KV 7.94 7.0 6.7 Meter 3.8 66KV 325 63 75 4.00 8.94 Minimum Height above Railway As Per IE-1957 Voltage Above 66KV up to 132KV Above 132KV up to 220KV Above 220KV up to 400KV Above 400KV up to 500KV Above 500KV up to 800KV Broad Meter & Narrow Gauges 14.58 5.132 220 400 800 6.05 3.84 12.0 3.58 5.60 Meter 15.3 meter for every additional 33KV Horizontal clearance between the conductor and Building High Voltage Up to 11 KV 11KV To 33KV 1.05 4.94 7.05 3.40 Meter Various Air clearances to be provided as per IE rule 64 Voltage KV BIL (Kvp) P-E (cm) P-P(cm) P-G (Meter) Section Clearance(Mt) 33KV 170 30 40 3.40 Minimum Clearance between Lines Crossing Each Other As Per IE-1957 Rules System Voltage Low & Medium 11-66KV 132KV 220KV 400KV 800KV 132KV 3.0 Meter .49 7.2 Meter 2.7 Meter + Add 0.49 7.40 Meter 17.49 5.5 220KV 1050 240 210 5.58 4.94 400KV 5.0 110KV 550 115 135 4.7 2.49 5.49 5.94 220KV 4.30 Meter 23.5 Clearances from Buildings of high and extra-high voltage lines IE Rule 80 Vertical Distance High voltage lines up to 33KV Extra High Voltage 3.49 7.58 4.49 5.5 4.90 Meter 19.3 400KV 1425 350 410 8.94 7. Open Balcony.3 meter for every additional 33KV Clearance between conductors and Trolley / Tram wires As per IE Rule 78 Low and Medium Voltage High Voltage Line Up to 11KV High Voltage Line Above to 11KV Extra High Voltage Line 1.5 Meter 5.8 Meter 2.1 Meter Over head Line Along Street (Parallel To Street) Low and Medium Voltage High Voltage 5.0 Meter Clearances from Buildings of low & medium voltage lines As Per IE Rule 79 For Flat roof.0 Meter 5.5 Meter 1.6 Meter 4.3 meter for every additional 33KV Clearance above ground of the lowest conductor As per IE Rule 77 Over head Line Across Street Low and Medium Voltage High Voltage 5.5 Meter 1.Extra High Voltage 2.2 Meter 5.0 Meter + Add 0.8 Meter Over head Line Without Across or Along Street Low/Medium /HT line up to 11KV If Bare Conductor Low/Medium /HT line up to 11KV If Insulated Conductor Above 11 KV Line Above 33KV Line 4.5 Meter 3. Verandah Roof and lean to Roof Line Passes Over Building Vertical Clearance Line Passes Adjustment of Building Horizontal Clearance For pitched Roof Line Passes Over Building Vertical Clearance Line Passes Adjustment of Building Horizontal Clearance 2.8 Meter + Add 0.2 Meter 2.2 Meter .8 Meter 6.2 Meter 1.