Recently Bureau of Indian Standards issued the Fourth revision of IS 1180 (Part 1): Outdoor Type Oil Immersed Distribution Transformers upto 2500 kVA, 33KV Specification. To discuss the various changes in design parameters of IS we had arranged a technical session in our office on dtd. 20.09.2014.
This session was headed by Mr. Arun Kumar (VP) having the vast experience in electrical & mechanical designing of transformer and previously he had served in BHEL, Haridwar as a design Head, Mr. Sandeep Kumar (AGM Design) & Mr. Gaurav Jain (Sr. Manager Marketing) have also attended the technical session to discuss the technical parameters which are defined in revised IS 1180. Our MD Mr. Girish Kumar also attended the technical session and also gives their valuable inputs in technical session.

 
In this technical session we have discussed the different categories in which transformers have been divided, which are as below.In revised IS 1180 there are three energy efficiency levels and for each categories, maximum values of total losses have been defined on 50% load and 100% load. Losses & percentage value of impedance for different categories are as below:
a) Three phase distribution transformers upto and including 200 KVA, 11KV Class

Sl. No.
Rating (KVA)
% Z
Energy Efficiency Level 1
Energy Efficiency Level 2
Energy Efficiency Level 3
@ 50%
@ 100%
@ 50%
@ 100%
@ 50%
@ 100%
1
16 KVA
4.5%
150W
480W
135W
440W
120W
400W
2
25 KVA
4.5%
210W
695W
190W
635W
175W
595W
3
63 KVA
4.5%
380W
1250W
340W
1140W
300W
1050W
4
100 KVA
4.5%
520W
1800W
475W
1650W
435W
1500W
5
160KVA
4.5%
770W
2200W
670W
1950W
570W
1700W
6
200KVA
4.5%
890W
2700W
780W
2300W
670W
2100W
b) Three phase distribution transformers Higher than 200 KVA upto and including 2500 KVA, 11KV Class

Sl. No.
Rating (KVA)
% Z
Energy Efficiency Level 1
Energy Efficiency Level 2
Energy Efficiency Level 3
@ 50%
@ 100%
@ 50%
@ 100%
@ 50%
@ 100%
1
250 KVA
4.5%
1050W
3150W
980W
2930W
920W
2700W
2
315 KVA
4.5%
1100W
3275W
1025W
3100W
955W
2750W
3
400 KVA
4.5%
1300W
3875W
1225W
3450W
1150W
3330 W
4
500 KVA
4.5%
1600W
4750W
1510W
4300W
1430W
4100W
5
630 KVA
4.5%
2000W
5855W
1860W
5300W
1745 W
4850W
6
1000 KVA
5.0%
3000W
9000W
2790W
7700W
2620W
7000W
7
1250 KVA
5.0%
3600W
10750W
3300W
9200W
3220W
8400W
8
1600 KVA
6.25%
4500W
13500W
4200W
11800W
3970W
11300W
9
2000 KVA
6.25%
5400W
17000W
5050W
15000W
4790W
14100W
10
2500 KVA
6.25%
6500W
20000W
6150W
18500W
5900W
17500 W
c) Single Phase distribution transformers upto and including 25 KVA, 11KV Class

Sl. No.
Rating (KVA)
% Z
Energy Efficiency Level 1
Energy Efficiency Level 2
Energy Efficiency Level 3
@ 50%
@ 100%
@ 50%
@ 100%
@ 50%
@ 100%
1
5KVA
4.0%
40W
115W
35W
95W
30W
75W
2
10KVA
4.0%
70W
190W
60W
170W
55W
150W
3
16KVA
4.0%
95W
265W
82W
224W
63W
190W
4
25KVA
4.0%
125W
340W
110W
300W
95W
260W
After study of the above we observe followings points which are important for design of transformers:
1) Mr. Sandeep pointed out that losses of energy efficiency level 1 are equivalent to BEE 3 Star Category, energy efficiency level 2 are equivalent to BEE 4 star category and energy efficiency level 3 are equivalent to 5star category for 3 phase distribution transformer upto 200 KVA transformer for 11KV Class.
2) Mr. Gaurav Jain pointed out that losses in energy efficiency level 1 are less than the losses mentioned in ECBC 2009 for transformers higher than 200 KVA upto and including 2500 KVA for 11KV Class
Further to above our design head 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 b) for 3 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 b) for 3 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 5% of the maximum total losses values mentioned in table c) for single phase.
In revised IS 1180 there are also some change in oil & winding temperature rise parameters for each category. It also includes the specification for corrugated type transformers. Since our MD Mr. Girish Kumar & our Organization is always emphasize & committed to saving the energy, so we appreciate the BIS & Government of India for taking this step. It will be a great tool for us to serve the nation by saving energy. SAI Electricals already has models HEFF for Level 1 and shortly will come up with models of transformers for Level 2 & Level 3.
In case any enquiry free feel to contact us at info@saielectricals.com or visit our website www.saielectricals.com