Fwd: Fw: Electrical Thumb Rules You MUST Follow (Part 4)

[Pankita Mehta]

On Friday, 15 November 2013 4:34 PM, EEP - Electrical Engineering Portal <in...@electrical-engineering-portal.com> wrote:

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Electrical Thumb Rules You MUST Follow (Part 4) Published on Nov 15, 2013 12:26 am by jiguparmar | Subscribe to Monthly Download Updates  Recommended  - ABB Electrical Installation Handbook PART II Forward this article to your colleagues Electrical Thumb Rules You MUST Follow - part 4 (on photo: distribution substation bus on a clear night in February by Eli Nelson) at Flickr Continued from: Electrical Thumb Rules You MUST Follow (Part 3) Eight rules to follow: Substation Capacity and Short Circuit Current Capacity (As per GERC) Substation Capacity and Short Circuit Current Capacity (As per Central Electricity Authority) Minimum Ground Clearance and Fault Clearing Time Busbar Ampere Rating Busbar Spacing Sound Level of Diesel Generator (ANSI 89.2 and NEMA 51.20) IR Value of Transformer Standard Size of MCB, MCCB, ELCB, RCCB, SFU and Fuse 1. Substation Capacity and Short Circuit Current Capacity As per GERC Voltage Sub Station Capacity Short Circuit Current 400 KV Up to 1000 MVA 40 KA  (1 to 3 Sec) 220 KV Up to 320 MVA 40 KA  (1 to 3 Sec) 132 KV Up to 150 MVA 32 KA  (1 to 3 Sec) 66 KV Up to 80 MVA 25 KA  (1 to 3 Sec) 33 KV 1.5 MVA to 5 MVA 35 KA (Urban) (1 to 3 Sec) 11 KV 150 KVA to 1.5 MVA 25 KA (Rural) (1 to 3 Sec) 415 V 6  KVA to 150 KVA 10 KA  (1 to 3 Sec) 220 V Up to 6 KVA 6 KA  (1 to 3 Sec) Go back to Rules ↑ 2. Substation Capacity and Short Circuit Current Capacity As per Central Electricity Authority Voltage Sub Station Capacity Short Circuit Current 765 KV 4500 MVA 31.5 KA for 1 Sec 400 KV 1500 MVA 31.5 KA for 1 Sec 220 KV 500 MVA 40 KA for 1 Sec 110/132 KV 150 MVA 40 KA or 50 KA for 1 Sec 66 KV 75 MVA 40 KA or 50 KA for 1 Sec Go back to Rules ↑ 3. Minimum Ground Clearance and Fault Clearing Time Voltage Min. Ground Clearance Fault Clear Time 400 KV 8.8 Meter 100 mille second 220 KV 8.0 Meter 120 mille second 132 KV 6.1 Meter 160 mille second 66 KV 5.1 Meter 300 mille second 33 KV 3.7 Meter - 11 KV 2.7 Meter - Go back to Rules ↑ 4. Busbar Ampere Rating For Phase Busbar Aluminium 130 Amp / Sq.cm or 800Amp / Sq.inch. For Phase Busbar Copper 160 Amp / Sq.cm or 1000Amp / Sq.inch For Neutral Busbar Same as Phase Busbar up to 200 Amp than Size of Neutral Busbar is at least half of Phase Busbar. Go back to Rules ↑ 5. Busbar Spacing Between Phase and Earth 26mm (Min) Between Phase and Phase 32mm (Min) Busbar Support between Two Insulator 250mm. Go back to Rules ↑ Advertisement 6. Sound Level of Diesel Generator (ANSI 89.2 and NEMA 51.20) KVA Max. Sound Level <9 KVA 40 DB 10 KVA to 50 KVA 45 DB 51 KVA to 150 KVA 50 DB 151 KVA to 300 KVA 55 DB 301 KVA to 500 KVA 60 DB Go back to Rules ↑ 7. IR Value of Transformer IR Value of Transformer Voltage 30°C 40°C 50°C >66KV 600MΩ 300MΩ 150MΩ 22KV to 33KV 500MΩ 250MΩ 125MΩ 6.6KV to 11KV 400MΩ 200MΩ 100MΩ <6.6KV 200MΩ 100MΩ 50MΩ 415V 100MΩ 50MΩ 20MΩ Go back to Rules ↑ 8. Standard Size of MCB, MCCB, ELCB, RCCB, SFU and Fuse MCB, MCCB, ELCB, RCCB, SFU, Fuse – Standard Ratings MCB Up to 63 Amp (80Amp and 100 Amp a    per Request) MCCB Up to 1600 Amp (2000 Amp as per Request) ACB Above 1000 Amp MCB Rating 6A,10A,16A,20A,32A,40A,50A,63A MCCB Rating 0.5A,1A,2A,4A,6A,10A,16A,20A,32A,40A,50A,63A,80A,100A (Domestic Max 6A) RCCB/ELCB 6A,10A,16A,20A,32A,40A,50A,63A,80A,100A Sen. of ELCB 30ma (Domestic),100ma (Industrial),300ma DPIC (Double Pole Iron Clad) main switch 5A,15A,30 A for 250V TPIC (Triple Pole Iron Clad) main switch 30A, 60A, 100A, 200 A For 500 V DPMCB 5A, 10A, 16A, 32A and 63 A for 250V TPMCCB 100A,200A, 300Aand 500 A For 660 V TPN main switch 30A, 60A, 100A, 200A, 300 A For 500 V TPNMCB 16A, 32A,63A For 500 V, beyond this TPNMCCB: 100A, 200A, 300A, 500 A For 660 V TPN Fuse Unit (Rewirable) 16A,32A,63A,100A,200A Change over switch (Off Load) 32A,63A,100A,200A,300A,400A,630A,800A SFU (Switch Fuse Unit) 32A,63A,100A,125A,160A,200A,250A,315A,400A,630A HRC Fuse TPN (Bakelite) 125A,160A,200A,250A,400A.630A HRC Fuse DPN (Bakelite) 16A,32A,63A MCB/MCCB/ELCB Termination Wire / Cable Up to 20A MCB Max. 25 Sq.mm 20A to 63A MCB Max. 35 Sq.mm MCCB Max. 25 Sq.mm 6A to 45A ELCB 16 Sq.mm 24A to 63A ELCB 35 Sq.mm 80A to 100A ELCB 50 Sq.mm Jump to original technical article at EEP - Electrical Thumb Rules You MUST Follow (Part 4)  Category & Tags:  Energy and Power, busbar, electrical thumb rules, ground clearance, short circuit current, short-circuit, substation, substation capacity Subscribe to Monthly Download Updates  Recently published technical articles:  Guidelines For The Construction And Maintenance Of Transmission Lines The Need for Load Shedding In Generating, Transmission and Distribution Systems What’s the worst source of fluctuations on a power supply system? 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