Diesel Generator Installation Guideline

August 10, 2023 1 Comment

 

Guideline for Generator (Government of Kerala-Department of Electrical Inspectorate)
SR. NO Capacity of Generator  Category
1 Up to 10KVA Portable Generator
2 10KVA to 100KVA Small Generators
3 100KVA to 1000KVA Medium Generators
4 Above 1000KVA Large Generators

 

Guideline for Portable Generator (Government of Kerala-Department of Electrical Inspectorate)
Size Generators up to 10kVA rating shall be treated as portable generators
ELCB Size ELCB having an operating time of 20ms at a residual current of 30mA shall be provided.
Neutral For 1phase generators one terminal shall be connected to earth and designated as the neutral.
3phase generators shall have their windings connected in star, with the star connection made available and connected to earth.
Single Phase DG use for Three Phase Supply The supply from a single-phase generator shall be feed to a three-phase supply system through a 4-pole change over switch subject to the following conditions:
(a) The neutral conductors of the load side and generator side shall be of adequate capacity to carry the total current in the neutral.
(b) The 3 poles in the 4 pole change over switch shall be linked by using rigid conductors of adequate short circuit and continuous current rating capacity
Location Portable generators shall be kept at a place, sufficiently ventilated so as to avoid possible hazards due to the accumulation of smoke and pollution.

 

Guideline for Medium Voltage Generator (Government of Kerala-Department of Electrical Inspectorate)
APPROVAL FROM ELECTRICAL INSPECTOR NOT Required: For generators of 10kVA to 30kVA rating completion report and SLD shall be submitted with a certification by the owner and the contractor stating that the electrical installation work is carried out by using change over switch, cable, MCB, etc. of standard make and with ISI mark for issuing the sanction for energization.
Required: For generators above 30kVA prior scheme approval shall be obtained
Meters Watt-hour meter and ammeters in each phase shall also be provided in GCP. For generators of 500 kVA and above, kVA/KW meter and P.F. meter shall also be provided
Exhaust Pipe Exhaust pipe of DG sets shall maintain a minimum height of 1.8 m clearance from floor level and shall be extended to a height of at least 1m above the building.
Clearance Minimum 1m clearances shall be provided on three sides of a generator set. When two generator sets are installed side-by-side, minimum 2.0 m clearance shall be provided between them
Location The generator sets should not be allowed to be installed above the ground floor or below first basement level of the building. There shall be provision of separate direct escape and entry into these areas from outside in case of fire.
Generators Running in Parallel Double frequency meter and double voltmeter, P.F Meter shall be provided in synchronizing panel / Control Panel.
For generators of 1MVA and above synchro check relay , kVA and kVAr meters, Reverse Reactive Power relays shall provide in synchronizing panel / Control Panel.
Neutral switching facility shall be provided. Interlock shall be provided to ensure that the generator breaker cannot be closed unless one of the neutral is connected to the earthing system
Neutral of largest capacity generator shall only be earthed. Neutrals of other generators, running in parallel, shall be in floating condition.
Also ensure that generator breakers can be made ‘ON’ only if functional neutral is earthed and closed.

 

Guideline for Change Over Switch of Portable Generator (Government of Kerala-Department of Electrical Inspectorate)
Capacity of single-Phase Generator  Change over switch rating Minimum copper area of conductors used for linking the poles
Up to 3 kVA 32 A 20 sq.mm
3 to 6 kVA 63 A 40 sq.mm
6 to 10 kVA 100A 60 sq.mm

 

Electricity Act, 2003 (Central Act No. 36 of 2003) & Central Electricity Authority Regulations, regulation 32, 2010
Inspection of D.G by Electrical Inspector All the apparatus of capacity above 100 KVA of the generating units including generating units producing electricity from renewable sources of energy shall be inspected by the Electrical Inspector before commissioning.

 

General Development Control Regulations, Gujarat – 2017
No construction shall be permissible in the Common Plot except Electric substation, Transformer room, Auxiliary power generator, Box-type transformer, section feeder pillar, meter room, over and underground water tank and pump room, security cabin, Community/ Society common amenities shall be allowed to be constructed in the Common Plot subject
22.14 Emergency Power Supply for Buildings height more than 45Meter and Special Buildings
1 For every building having height more than 45mts, a stand‐by electric generator shall be installed to supply power to staircase and corridor lighting circuits, fire lifts, the stand‐by fire pump, pressurization fans and blowers, smoke extraction and damper systems in case of failure of normal electric supply.
2 The generator shall be capable of taking starting current of all the machines and circuits stated above simultaneously. If the stand‐by pump is driven by diesel engine, the generator supply need not be connected to the main electrical pump. Where parallel HT/LT supply from a separate sub‐station is provided with appropriate transformer for emergency, the provision of generator may be waived in consultation with Authority
22.15 Electric Supply and Installation for Buildings with height more than 25mts and Special Buildings
1 Electric supply to the High pressure Fire pump, Fire Lift and Sprinkler pump shall be supplied parallel to the building supply and should not get cut‐off if the supply to the building is switched off.
2 All the electric wiring used shall be of 900 volt grading and connected to each enclosure through a MCB for a particular load.
3 Electric cable/wires used shall be of 700 volt grading with Mechanical circuit breaker and earth Leak Circuit Breaker (MCB and ELCB).

 

Government of Kerala-Department of Electrical Inspectorate
Location of DG sets The DG sets shall be installed at Ground level or First Basement Floor level, installation of DG sets at combined two upper basement floors with access from ground level is allowed

 

Diesel generator NBC -2016 (3.4.6.4 / 3.4.6.2)
Installation Diesel generator set(s)shall not be installed at any floor other than ground / first basement. If the same are installed indoors, proper ventilation and exhaust shall be planned. The DG set room shall be separated by 120 min fire resistance rated walls and doors.
Fuel Tank The oil tank for the DG sets (if not in the base of the DG) shall be provided with a enclosure having a volumetric capacity of at least 10 percent more than the volume of the oil tank. The enclosure shall be filled with sand for a height of 300 mm.
D.G Power Supply for Building Emergency power supplying distribution system for critical requirement for functioning of fire and life safety system and equipment shall be planned for efficient and reliable power and control supply to the following systems and equipment where provided:
(a) Fire pumps.
(b) Pressurization and smoke venting; including its ancillary systems such as dampers and actuators.
(c) Fireman’s lifts (including all lifts).
(d) Exit signage lighting.
(e) Emergency lighting.
(f) Fire alarm system.
(g) Public address (PA) system (relating to emergency voice evacuation and annunciation).
(h) Magnetic door hold open devices.
 (j) Lighting in fire command centre and security room.
Power supply to these systems and equipment shall be from normal and emergency (standby generator) power sources with changeover facility.
If power supply, is from HV source and HV generation, the transformer should be planned in standby capacity to ensure continuity of power to such systems.
 Wherever transformers are installed at higher levels in buildings and backup DG sets are of higher voltage rating, then dual redundant cables shall be taken to all transformers. The generator shall be capable of taking starting current of all the fire and life safety systems and equipment as above.
Where parallel HV/LV supply from a separate substation fed from different grid is provided with appropriate transformer for emergency, the provision of generator may be waived in consultation with the Authority

 

General Guideline for Diesel Generator Set
Foundation DG set’s location area / foundation should be capable to bear the STATIC load and DYNAMIC Load which is typically 2.5 times the static load during running.
The length and breadth of foundation should be minimum 150 mm (6”) more than acoustic enclosure size / base rails size
It is recommended to have foundation elevation 150 mm above finish ground level. It helps to maintain cleanliness of DG Set. For areas having heavy rainfall, a higher platform/ rain shed (not mandatory) may be required to prevent water entry and it also helps in operator’s safety
DG Set foundation level to be checked with water level tube at frame mounting area and should be within +/- 5mm for 750 kVA and above DG Set. For DG sets below 750 kVA +/- 2.5mm to be maintained. Metal shims to be provided between DG frame and civil foundation to load DG Set uniformly.
Fuel Tank For DG sets of rating up to 700 kVA the fuel tank is in sub-base type part of DG Set skid.
For DG sets above 750 kVA, 990Liter capacity day tank is supplied loose, which needs to be installed at floor level or 300 mm above the DG floor level to maintain positive suction head on fuel pump inlet.
The height of the day tank should be sufficient to put a positive head on the engine fuel pump. (Minimum level in tank not less than 6 inches [150 mm] above engine fuel inlet.)
The maximum height of fuel in the day tank should not be sufficient to put a positive head on the engine fuel return lines. Please ensure that all diesel lines are leak proof and should prevent air seepage even if the DG sets is not run for a long time.
Control Panel The control panel of the generator should be located away from the generator, but in the same room. The clearance between the generator and the control panel should be more than 1 meter, for small sets up to and including 5OO KVA. For larger sets, more separation for proper cooling is the deciding factor
Two D.G sets side by Side When two generators are erected side by side, a minimum clearance of 1500 mm should be provided between the generators.
Protection Up to and inclusive of 100 KVA: Switch fuse, Fuse Switch or Circuit Breaker. Above 100 KVA: Circuit Breaker.
All generators with rating of 100 KVA and above shall be protected against earth fault leakage. Protected against faults within the generator winding using restricted earth fault protection or differential protection or by both

 

D.G Set Spacing Guideline
Description DG set with
Acoustic Enclosure in Open Area.		 DG set with
Acoustic
Enclosure in
Covered Area.		 Open DG set in room.
Free space on both sides Min. 1.5 Meter Min. 1.5 Meter Min. 2 Meter
Free space at front side (Radiator- Hot air outlet at front) Min. 3 Meter Min. 3Meter
(with ducting to avoid
re-circulation)		 Min. 1.5 Meter
Free space at front side (Radiator- Hot air outlet at top) Min. 1 Meter Min. 1.5 Meter N/A
Free space at rear side (Alternator) Min. 2 Meter Min. 2 Meter Min. 2 Meter
Fresh air inlet opening area N/A N/A Min 1.5 times of the Radiator area.
Hot air discharge opening area N/A N/A Min 2.5 times of the Radiator area.
Distance between two sets Min 1.5 Meter
between two
canopies		 Min 1.5 Meter between
two canopies		 Min 1.5 Meter
between two
foundations.

 

D.G SET CABLE SIZE

DG SIZE AMP CABLE SIZE X NO OF CABLE
2000 KVA 2782 A 500 x 10
1800 KVA 2504 A 400 x 10
1500 KVA 2087 A 400 x 8 300 x 9 240 x 10
1250 KVA 1739 A 400 x 7  300 x 8  240 x 9
1000 KVA 1391 A  300 x 6  225 x 7
750 KVA 1043 A 400 x 4 240 x 5  185 x 6
650 KVA 904 A 300 x 4  225 x 5  150 x 6
625 KVA 870 A 300 x 4  185 x 5  120 x 6
600 KVA 835 A 240 x 4  185 x 5  120 x 6
500 KVA 696 A  300 x 3 185 x 4 120 x 5
450 KVA 626 A 240 x 3  150 x 4  95 x 5
380 KVA 529 A  400 x 2 185 x 3 120 x 4
320 KVA 445 A  300 x 2  150 x 3 95 x 4
285 KVA 396 A 225 x 2  120 x 3  70 x 4
250 KVA 348 A 400 x 1 185 x 2 95 x 3
225 KVA 313 A 400 x 1 150 x 2
200 KVA 278 A 300 x 1
180 KVA 250 A 240 x 1
160 KVA 223 A 185 x 1
140 KVA 195 A 150 x 1
125 KVA 174 A 120 x 1
100 KVA 139 A 95 x 1
82.5 KVA 115 A 70 x 1
75 KVA 104 A 50 x 1
62.5 KVA 87 A 35 x 1
50 KVA 70 A 25 x 1
30 KVA 42 A 16 x 1
25 KVA 40 A 10 x 4
20 KVA 40 A 10 x 4
15 KVA 32 A 6 x 4

 

Diesel Generator Details
Diesel Generator Size Typical Room Size (LXWXH) Lubrication System Capacity Coolant Capacity                       (H for HE, R for Radiator)
2000 KVA 12.5 x 7.5 x 6.5 400Liter 550 (H) 750 (R)
1800 KVA 12.5 x 7.5 x 6.5 400Liter 550 (H) 750 (R)
1500 KVA 12.5 x 7.5 x 6.5 177Liter 320 (H) 555 (R)
1250 KVA 12.5 x 7.5 x 6.5 177Liter 310 (H) 440 (R)
1000 KVA 11.0 x 7.0 x 6.5 145Liter 199 (H) 260 (R)
750 KVA 9. 0 x 6.0 x 5.0 118Liter 230 (H) 300 (R)
650 KVA 8.5 x 6.0 x 5.0 95Liter 212 (H) 250 (R)
625 KVA 8.5 x 6.0 x 5.0 95Liter 210 (H) 240 (R)
600 KVA 8.5 x 6.0 x 5.0 95Liter 210 (H) 240 (R)
500 KVA 8.5 x 6.0 x 5.0 55Liter 125 (H) 175 (R)
450 KVA 8.5 x 6.0 x 5.0 55Liter 125 (H) 175 (R)
380 KVA 8.0 x 5.5 x 5.0 55Liter 80 (H) 115 (R)
320 KVA 7.5 x 5.0 x 5.0 39Liter 45 (H) 76 (R)
285 KVA 7.5 x 5.0 x 5.0 39Liter 40 (H) 95 (R)
250 KVA 7.5 x 5.0 x 5.0 39Liter 47 (H) 80 (R)
225 KVA 7.5 x 5.0 x 5.0 39Liter 47 (H) 80 (R)
200 KVA 6.5 x 4.5 x 3.5 24Liter 28 (R)
180 KVA 6.5 x 4.5 x 3.5 24Liter 27 (R)
160 KVA 6.5 x 4.5 x 3.5 24Liter 27 (R)
140 KVA 6.5 x 4.5 x 3.5 24Liter 27 (R)
125 KVA 6.0 x 4.0 x 3.5 14.3Liter 25 (R)
100 KVA 6.0 x 4.0 x 3.5 14.3Liter 22 (R)
82.5 KVA 6.0 x 4.0 x 3.5 14.3Liter 22 (R)
75 KVA 6.0 x 4.0 x 3.5 9Liter 13 (R)
62.5 KVA 6.0 x 3.5 x 3.0 9Liter 11 (R)
50 KVA 6.0 x 3.5 x 3.0 9Liter 11 (R)
30 KVA 6.0 x 3.5 x 3.0 9Liter 11 (R)
25 KVA 4.0 x 1.5 x 2.0 6.5Liter 7.5 (R)
20 KVA 4.0 x 1.5 x 2.0 6.5Liter 7.5 (R)
15 KVA 4.0 x 1.5 x 2.0 5Liter 6 (R)

 

Size of Cables, Earthing conductors and protection of Generators
Generator Capacity Full load Current rating Cable size
AYFY		 Earth conductor
size (mm2/SWG)		 Protection Panel
Meters
5 KVA 7 A 4 mm2 8.3/10 MCB/MCCB
7.5 KVA 10.5 A 4 mm2 8.3/10 MCB/MCCB
10 KVA 14 A 4.8 mm2 8.3/10 MCB/MCCB
12.5 KVA 17.5 A 6 mm2 8.3/10 MCB/MCCB AM,VM, FM&EM
15 KVA 21 A 10 mm2 8.3/10 MCB/MCCB
20 KVA 28 A 10 mm2 8.3/10 MCB/MCCB
25 KVA 35 A 16 mm2 18.6/6 MCB/MCCB
30 KVA 42 A 16 mm2 18.6/6 MCB/MCCB
35 KVA 49 A 25 mm2 18.6/6 MCB/MCCB
40 KVA 56 A 35 mm2 27.27/4 MCB/MCCB
45 KVA 63 A 35 mm2 27.27/4 MCB/MCCB
50 KVA 70 A 35 mm2 27.27/4 MCB/MCCB
63 KVA 88 A 50 mm2 27.27/4 MCB/MCCB
75 KVA 105 A 95 mm2 25×3 MCB/MCCB
82.5 KVA 115 A 95 mm2 25×3 MCB/MCCB
100 KVA 140 A 120 mm2 25×3 MCCB + standby low set earth fault relay using CT in neutral earthing conductor
125 KVA 175 A 150 mm2 25×3
160 KVA 224 A 185 mm2 25×3
180 KVA 252 A 185 mm2 25×3
200 KVA 280 A 2×120  mm2 25×3
225 KVA 315 A 2×120  mm2 25×3
250 KVA 350 A 2×185 mm2 25×3
320 KVA 448 A 2×300 mm2 25×3
400 KVA 560 A 2×400 mm2 25×3
500 KVA 700 A 3×400 mm2 25×3 ACB with overload and E/F release and stand by low set earth fault relay using CT in neutral earthing conductor AM,VM,
FM, EM,
PFM,
KVAM or
KVM
625 KVA 875 A 4×400 mm2 25×3
750 KVA 1050 A 4 x400 Al
XLPE cable or
Bus Trunking.		 25×3
1000 kVA
and above,		 ACB with thermal O/L, voltage-controlled O/C relay, over voltage, under voltage, negative sequence, low set stand by earth fault relays and REF/Differential relay with fuel shut off facilities. Over speed protection shall be provided for the engine

 

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