After successful installation it is very important to take care of the various safety measures during operation of transformer. Fire protection is one of the major safety measures for transformers. Since transformer oil have been used as a insulating medium in transformer therefore its quality plays a vital role for safety it means there will be no compromise in the quality of transformer oil.
Recently specifications for transformers with ester based oil as a insulating oil have been adopted. Since ester based transformer oil have high fire point, protection against fire hazardous have been also increased.
Experience shows that transformer fires can be particularly spreading at frightening speeds and causing extensive damage, unfortunately these fires are too common in today’s modern power distribution networks In urban areas with dense population fire spread rapidly and loss of life could be there. Ester based transformer oil offers the perfect solution to avoiding the unnecessary risk of a fire and high degree of fire safety due to high fire point and higher resistance to ignition. Here we are giving one small comparison between mineral oil and ester based oil.

Oil Type
Flash Point
Fire Point
Mineral Oil
150 Deg C
170 Deg C
Ester Oil
260 Deg C
300 deg C

 
From above graph we can observe that ignition resistance of ester based oil is much higher than Mineral Oil after 70 minutes and a temperature of more than 260 deg C the insulating fluid still not ignite and shows high excellent resistance to ignition.
Besides of above there are some additional advantages of using the synthetic ester based transformer oil, some of the advantages are as below:
a) 100% fire safety record
b) High fire point (>300°C)
c) Suitable for indoor and outdoor installation
d) Reduced protection costs
e) High Performance and Low Maintenance
f) Robust and stable at high temperatures over long periods
g) No corrosive Sulphur
h) No sludge formation
i) Absorbs large amounts of moisture with no reduction of breakdown voltage (up to 600ppm)
j) Reduces the risk of bubble formation
k) Readily / fully biodegradable
l) Asset Life Extension Slower rate of cellulose ageing than mineral oil
m) Longer lifetime at standard temperatures
In addition of above if we talk about the dry type transformers which are sold as a fire safe solution for indoor & underground installations. Although these types of transformers have found wide application they do have some disadvantages and their reliability record has been called into question in some of the more demanding transformer applications. Ester based oil filled transformers can offer a fire safe solution, without any drawbacks in comparison of cast resin transformers.
Comparison of Main Properties of Ester Oil Filled & Cast Resin Type transformers
Ester Oil Transformer
Cast Resin
Fire Resistance
Excellent
Moderate
Environmental Impact
Excellent
Moderate
Life Expectancy
High
Moderate
No Load Losses & Load Losses
High
Low to Moderate
Sound Level
Low
Moderate
Operating Temperature
Low
Moderate
Contamination Resistance
Excellent
Moderate
Overload Capacity
Excellent
Moderate
Maintenance
None on sealed transformers
Regular cleaning and crack detection
Fault Diagnosis (DGA)
Yes
No
Repair Possible
Yes
Difficult


So we conclude from above that by changing the insulating oil with synthetic ester based oil from mineral oil there is the possibility to increase reliability and significantly reduce maintenance costs. The initial cost of the ester based oil may be higher, but maintenance cost gets reduced and asset life will get increased. Further initial cost of cast resin transformer is also high but if we compare the life cycle of ester oil transformer with cast resin transformer, ester oil transformer cheaper and reliable and maintenance cost also got reduced.
In case any enquiry free feel to contact us at info@saielectricals.com and visit our website http://www.saielectricals.com/

   *Technical data have been taken from Midel Oil Data sheets