Page 40 - ECLECTIC MARCH-2022 INSIDE PAGES_p2.indd
P. 40
ure 1: States a sketch of aging rates due to different important that during installation and commissioning,
aging mechanism. The arrow shows the effect of increased CCA of Transformers are kept substantially dehydrated.
Water Content increasing Hydrolysis. Otherwise, decaying of solid insulation will occur in
On the other hand, Figure 2 illustrates the effect of greater extent from the nascent stage of the Transformer
moisture to the life expectancy of a transformer. and its life expectancy will reduce drastically.
Figure 2: Previously, we used to carry out rigorous filtration of
Other than this the moisture inside solid insulation can insulating oil and under vacuum filling of processed oil
create water bubble at high temperature. This water in order to satisfy dehydrated condition of CCA. Now, we
bubble bearing conductive property can cause severe have additionally adopted usage of‘Dry Air Treatment’and
damage to the winding while passing through the subsequent ‘Dew Point & Relative Humidity Monitoring’
winding duct. into the existing practice.
Considering this detrimental moisture operation
within in-service Power Transformers, it is very much MOISTURE CONTAMINATION DURING
INSTALLATION
During installation process, there are four probable
sources of moisture ingression and contamination with
solid insulation inside a transformer.
i. During transportation from factory to Site
ii. During in situ open tank inspection of CCA & OLTC
inside the main tank
iii. During repairing of any kind of fault, damage or
abnormality prior to oil filling
iv. During installation of accessories like Turret CTs,
Bushings etc. which is directly linked up with exposure
of winding to the atmosphere
On Receipt of the Main Tank at Site
In our system, most of the power transformers are
transported from Manufacturer’s factory to Customer
site with N2 or Dry Air filled inside the Main Tank. It is
recommended to measure the quality parameters like Dew
Point, Temperature & Relative Humidity of the Transport
Gas on receipt of the main tank to rule out any possibilities
of contamination during transportation. It may be safely
assumed that the transformer has not been contaminated
in transit with outside air or moisture if the dew point of
the gas indicates a relative humidity of less than 1%.
Power Transformers, under discussion, were transported
from manufacturer’s factory at Mumbai to Kolkata. One
of them was transported and installed in an extremely
40
aging mechanism. The arrow shows the effect of increased CCA of Transformers are kept substantially dehydrated.
Water Content increasing Hydrolysis. Otherwise, decaying of solid insulation will occur in
On the other hand, Figure 2 illustrates the effect of greater extent from the nascent stage of the Transformer
moisture to the life expectancy of a transformer. and its life expectancy will reduce drastically.
Figure 2: Previously, we used to carry out rigorous filtration of
Other than this the moisture inside solid insulation can insulating oil and under vacuum filling of processed oil
create water bubble at high temperature. This water in order to satisfy dehydrated condition of CCA. Now, we
bubble bearing conductive property can cause severe have additionally adopted usage of‘Dry Air Treatment’and
damage to the winding while passing through the subsequent ‘Dew Point & Relative Humidity Monitoring’
winding duct. into the existing practice.
Considering this detrimental moisture operation
within in-service Power Transformers, it is very much MOISTURE CONTAMINATION DURING
INSTALLATION
During installation process, there are four probable
sources of moisture ingression and contamination with
solid insulation inside a transformer.
i. During transportation from factory to Site
ii. During in situ open tank inspection of CCA & OLTC
inside the main tank
iii. During repairing of any kind of fault, damage or
abnormality prior to oil filling
iv. During installation of accessories like Turret CTs,
Bushings etc. which is directly linked up with exposure
of winding to the atmosphere
On Receipt of the Main Tank at Site
In our system, most of the power transformers are
transported from Manufacturer’s factory to Customer
site with N2 or Dry Air filled inside the Main Tank. It is
recommended to measure the quality parameters like Dew
Point, Temperature & Relative Humidity of the Transport
Gas on receipt of the main tank to rule out any possibilities
of contamination during transportation. It may be safely
assumed that the transformer has not been contaminated
in transit with outside air or moisture if the dew point of
the gas indicates a relative humidity of less than 1%.
Power Transformers, under discussion, were transported
from manufacturer’s factory at Mumbai to Kolkata. One
of them was transported and installed in an extremely
40
