High-efficiency transformers make financial benefits for the society. Other than diminished greenhouse gas emanations, they progress reliability and deliver possibly longer benefit life by bringing down temperature rises through energy-efficiency advancements. India has, by presently, received the universal IEC standards as well as presented star naming for chosen categories of transformers. Most power losses happen within the transformer core made up of magnetic steel or within the electrical coils or windings of either aluminum or copper. Copper diminishes load loss, since it could be a more proficient conductor.
Phase | Three Phase |
Frequency | 50 Hz |
Winding Material | Copper/Aluminium |
Ratings | Upto 200 kVA |
Primary voltage | Upto 11000 V |
Secondary Voltage | 433 V |
Temperature Rise | 35 C / 40 C |
Star Rating Distribution Transformers with Energy efficiency level 2 as per IS 1180:2014 (Part I)
- Maximum Ambient Temperature=45°C
- Oil temperature Rise: 35°C
- Winding Rise: 40°C
- Tap switch: NIL(For 16 KVA to 100 KVA)
- Type Of Winding Aluminum wound Off circuit Tap switch: +5% to -5% @ 2.5%(For 160 & 200 KVA)
- TOC (Total Owning cost) = IC+ (A X Wi ) +(B X Wc)
- IC = Initial cost (unit end cost without tax) of transformer as quoted by the bidder.
- Wi = No Load losses quoted by the bidder in Watt
Wc = Full load losses at 75 °C quoted by the bidder in Watt - A Factor = Cost of no load losses in Rs/ Watt
B Factor = Cost of full load losses at 75 °C in Rs. / Watt
Distribution Transformer in KVA | Level 1 rated Transformer | Level 2 rated Transformer | ||
*Total loss in watts at 100 % loading should not be lower than | *Total loss in watts at 100 | *Total loss in watts at 100 % loading should not be lower than (Not equal to) | *Total loss in watts at 100 | |
5 | 95 | 115 | 75 | 95 |
10 | 240 | 270 | 215 | 240 |
16 | 440 | 480 | 400 | 440 |
25 | 635 | 695 | 595 | 635 |
63 | 1140 | 1250 | 1050 | 1140 |
100 | 1650 | 1800 | 1500 | 1650 |
200 | 2300 | 2700 | 2100 | 2300 |
500 | 4300 | 4750 | 4100 | 4300 |
Rating of Transformer in KVA | Percentage Impedance at 750C |
5 KVA | 4.00 % |
10 KVA to 100 KVA | 4.50 % |
200 KVA & 500 KVA | 4.75% |
Temperature Rise | 5 KVA | 10 to 500 KVA | |||
Top oil temperature | rise | measured | by | 30 deg.C | 35 deg.C |
Winding temperature | rise | measured | by | 35 deg.C | 40 deg.C |
- Measurement of winding resistance (at all taps if applicable) [IS2026 (Part1)].
- Measurement of voltage ratio, polarity, phase sequence and vector group[IS2026(Part1)].
- Measurement of short-circuit impedance (principal tapping, when applicable)
- Load losses at rated current and normal frequency,at50 % and100 % load [IS2026(Part1)].
- Measurement of no-load loss and current [IS2026(Part1)].
- Measurement of insulation resistance [IS2026(Part1)].
- Induced over-voltage withstand test[IS2026 (Part3)].
- Separate-source voltage withstand test [IS2026(Part3)].
- Pressure and vacuum test(as per IS: 1180-2014).
- Oil leakage test(as per IS: 1180-2014).
- Neutral current measurement, shall not be more than 2% of full load current (CEA Guideline 2008 clause no 34.9)
- Oil samples (one sample per lot) to comply with IS 1866.
- Measurement of no load losses and magnetizing current at rated frequency and at 90%, 100%and 112.5% voltage
In revised IS specification, losses for each rating for each category have been defined in three levels which are denoted by as follows;
- a) Energy Efficiency Level 1
- b) Energy Efficiency Level 2
- 3) Energy Efficiency Level 3
In each level maximum losses (No Load Loss + Load Loss) at 50% load & 100% load have been specified for each rating in all categories.
a) Three phase distribution transformers upto and including 200KVA, 11KV Class
Sl. No. | Rating (KVA) | % Z | Energy Efficiency Level 1 | Energy Efficiency Level 2 | ||
@ 50% | @ 100% | @ 50% | @ 100% | |||
1 | 16KVA | 4.5% | 150W | 480W | 135W | 440W |
2 | 25KVA | 4.5% | 210W | 695W | 190W | 635W |
3 | 63KVA | 4.5% | 380W | 1250W | 340W | 1140W |
4 | 100KVA | 4.5% | 520W | 1800W | 475W | 1650W |
5 | 160KVA | 4.5% | 770W | 2200W | 670W | 1950W |
6 | 200KVA | 4.5% | 890W | 2700W | 780W | 2300W |
b) Three phase distribution transformers Higher than 200KVA upto and including 2500KVA, 11KV Class
Sl. No. | Rating (KVA) | % Z | Energy Efficiency Level 1 | Energy Efficiency Level 2 | ||
@ 50% | @ 100% | @ 50% | @ 100% | |||
1 | 250KVA | 4.5% | 1050W | 3150W | 980W | 2930W |
2 | 315KVA | 4.5% | 1100W | 3275W | 1025W | 3100W |
3 | 400KVA | 4.5% | 1300W | 3875W | 1225W | 3450W |
4 | 500KVA | 4.5% | 1600W | 4750W | 1510W | 4300W |
5 | 630KVA | 4.5% | 2000W | 5855W | 1860W | 5300W |
6 | 1000KVA | 5.0% | 3000W | 9000W | 2790W | 7700W |
7 | 1250KVA | 5.0% | 3600W | 10750W | 3300W | 9200W |
8 | 1600KVA | 6.25% | 4500W | 13500W | 4200W | 11800W |
9 | 2000KVA | 6.25% | 5400W | 17000W | 5050W | 15000W |
10 | 2500KVA | 6.25% | 6500W | 20000W | 6150W | 18500W |
Sl. No. | Rating (KVA) | % Z | Energy Efficiency Level 1 | Energy Efficiency Level 2 | ||
@ 50% | @ 100% | @ 50% | @ 100% | |||
1 | 5KVA | 4.0% | 40W | 115W | 35W | 95W |
2 | 10KVA | 4.0% | 70W | 190W | 60W | 170W |
3 | 16KVA | 4.0% | 95W | 265W | 82W | 224W |
4 | 25KVA | 4.0% | 125W | 340W | 110W | 300W |
Further to above it is also observed that IS 1180 are now also applicable for 22KV & 33KV class transformers, losses values for 22KV & 33KV class transformers shall be applicable as per below clause:
- a) For transformers having voltage class above 11KV and upto and including 22KV, the permissible total loss value shall not exceed by 5% of the maximum total losses values mentioned in table a) & b) for three phase.
- b) For transformers having voltage class above 22KV and upto and including 33KV, the permissible total loss value shall not exceed by 7.5% of the maximum total losses values mentioned in table a) & b) for three phase.
- c) For transformers having voltage class above 11KV and upto and including 22KV, the permissible total loss value shall not exceed by 7.5% of the maximum total losses values mentioned in table c) for single phase.
- d) For transformers having voltage class above 22KV and upto and including 33KV, the permissible total loss value shall not exceed by 10% of the maximum total losses values mentioned in table c) for single phase.
for any requirement of Distribution transformer please feel free to call or whatsapp +91-9818596585 or mail at akil@pvjpower.in
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