TECHNICAL FIELD
The present disclosure generally relates to a cooling system for a transformer and, in
particular, relates to a method and a system for controlling water pressure for harnessing in
a water-cooled transformer.
BACKGROUND
Background description includes information that may be useful in understanding the
present subject matter. It is not an admission that any of the information provided herein is
prior art or relevant to the presently claimed subject matter, or that any publication
specifically or implicitly referenced is prior art.
Power transformer is a vital equipment for transfer of large volume of power from source
to utility. During the power transfer, some amount of energy gets wasted. This energy is
manifested in the form of heat. In order to limit the temperature of the transformer below a
specified value, the heat generated by the transformer is to be carried out.
There exists different methods of carrying the heat from the transformer including, for
example, oil-oil-air, oil-air, oil-water, and so forth. Each method of cooling has variable
parameters like size, power consumed, complexity in operation, maintainability, etc. Since
power and rectifier transformers are customized as per the requirement, the installation
condition depends upon the preference of end user. For instance, the end user can choose
any particular method of cooling based on the transformer requirement.

In some cases of existing large power and rectifier transformers which are put for industrial
applications, oil-water cooling method employing oil forced water forced (OFWF) cooler is
preferred. The specific advantage of selecting this type cooling is attributed to compact size
of cooler with minimum foot print, less power consumption for cooling, easy in operation
and maintenance. However, the requirement is associated with availability of required flow
of water.
For the transformer, which is decided to be cooled by OFWF coolers, it is mandatory to test
the transformers at manufacturing works with OFWF coolers with flow of water identical
to the volume and pressure head of water available at site.
In one example, at manufacturing works, free flow of water is available at very little
pressure. In such a situation, a separate set of pumps is required for manipulating the cooling
water pressure to make it suitable for the oil-water cooler. Since the transformer is tailor
made for customized jobs, a separate set of pumps is required for separate transformer to
make the cooling water available at required pressure (psi) and volume (liter per minute).
The pump as always, few complicacies, power consumption and maintainability issues
persist.
In another example, site water is available at very high-pressure head and that has to be
reduced down to a level in order to make it suitable for feeding the OFWF cooler of the
transformer. For this purpose, a pressure reducing valve is provided in the oil circuit whose
purpose is to reduce the pressure of the water entering into the cooler which is a complicated
design.
Thus, there remains a need for method and system where no separate pump is required for
manipulating the water pressure to make it suitable for cooling of the transformer during
testing of the transformer. Also, there is need for system and method for increasing or
reducing the available water pressure to make the water pressure suitable for using in the
oil-water cooler of the transformer during a testing of the transformer.

OBJECTS OF THE DISCLOSURE
In view of the foregoing limitations inherent in the state of the art, some of the objects of
the present disclosure, which at least one embodiment herein satisfy, are listed herein below.
It is an object of the present disclosure to propose a method for changing the water pressure
suitable for water cooled transformer using oil forced water forced (OFWF) cooler.
It is another object of the present disclosure to propose a system and method of changing
the water pressure, by improving reliability of the availability of suitable water for the
OFWF cooler of the transformer.
It is yet another object of the present disclosure to propose a method that could be
universally utilized at for testing the transformer at manufacturing works for changing the
water pressure, i.e., one system can be made applicable to different pressure heads as per
requirement.
It is still yet another object of the present disclosure to propose a method for changing the
water pressure without employing any electricity for running of pumps there by reducing
cost and improving availability of the transformer.
It is a further object of the present disclosure to propose a method for changing the water
pressure at site eliminating the complicated and costliest and specialized equipment like
pressure reducer valve.
These and other objects and advantages of the present invention will be apparent to those
skilled in the art after a consideration of the following detailed description taken in
conjunction with the accompanying drawings in which a preferred form of the present
invention is illustrated.

SUMMARY
This summary is provided to introduce concepts related to a method and a system for
controlling water pressure for harnessing in a water-cooled transformer. The concepts are
further described below in the detailed description. This summary is not intended to identify
key features or essential features of the claimed subject matter, nor is it intended to be used
to limit the scope of the claimed subject matter.
The present disclosure relates to a method for controlling water pressure for harnessing in a
water-cooled transformer. The method includes ascertaining a desired water pressure with
which the water is to be supplied to a water inlet of a water cooler coupled to the power and
rectifier transformer; and storing a water tank fluidly connected to the water inlet up to a
predefined level corresponding to the ascertained water pressure, so as to achieve the desired
water pressure.
In an aspect, the storing includes filling the water in the water tank to one the predefined
levels to increase or decrease the water pressure up to the desired water pressure.
In an aspect, the water cooler is an oil forced water forced (OFWF) water cooler.
The present disclosure relates to a system for controlling water pressure for harnessing in a
water-cooled transformer. The system includes a water cooler for receiving and cooling the
oil circulated through an oil inlet and oil outlet connected to the power and rectifier
transformer; and a water tank fluidly connected to a water inlet of the water cooler. In an
aspect, the water tank is to store the water up to a predefined level corresponding to a water
pressure with which the water is to be supplied to the water inlet, so as to achieve the desired
water pressure.

In an aspect, the water tank is filled up to one the predefined levels to increase or decrease
the water pressure up to the desired water pressure.
In an aspect, the water cooler is an oil forced water forced (OFWF) water cooler.
Other objects, features and advantages of the present disclosure will become apparent from
the following detailed description. It should be understood, however, that the detailed
description and the specific examples, while indicating specific embodiments of the
invention, are given by way of illustration only, since various changes and modifications
within the spirit and scope of the invention will become apparent to those skilled in the art
from this detailed description.
BRIEF DESCRIPTION OF DRAWINGS
While the specification concludes with claims particularly pointing out and distinctly
claiming the subject matter that is regarded as forming the present subject matter, it is
believed that the present disclosure will be better understood from the following description
taken in conjunction with the accompanying drawings, where like reference numerals
designate like structural and other elements, in which:
FIG. 1 shows a conventional arrangement of a power transformer testing with oil-water
assembled cooler;
FIG. 2 shows a conventional arrangement of the power transformer testing with oil-water
cooler assembly at site;
FIG. 3 shows a conventional arrangement of the power transformer testing with oil-water
assembled cooler with water pump in circuit;
FIG. 4 shows a conventional arrangement of the power transformer testing with oil-water
cooler assembly with pressure reducing valve at site;

FIG. 5 shows a system of changing pressure in a water pipe of a power transformer at site
in an accordance with an embodiment of the present disclosure; and
FIG. 6 shows a method of changing water pressure in a power and rectifier transformer
which are equipped with oil-water coolers, in accordance with an embodiment of the present
disclosure.
DETAILED DESCRIPTION
The detailed description of various exemplary embodiments of the disclosure is described
herein with reference to the accompanying drawings. It should be noted that the
embodiments are described herein in such details as to clearly communicate the disclosure.
However, the amount of details provided herein is not intended to limit the anticipated
variations of embodiments; on the contrary, the intention is to cover all modifications,
equivalents, and alternatives falling within the spirit and scope of the present disclosure as
defined by the appended claims.
It is also to be understood that various arrangements may be devised that, although not
explicitly described or shown herein, embody the principles of the present disclosure.
Moreover, all statements herein reciting principles, aspects, and embodiments of the present
disclosure, as well as specific examples, are intended to encompass equivalents thereof.
The terminology used herein is for the purpose of describing particular embodiments only
and is not intended to be limiting of example embodiments. As used herein, the singular
forms “a”, “an”, and “the” are intended to include the plural forms as well, unless the context
clearly indicates otherwise. It will be further understood that the terms “comprises”,
“comprising”, “includes”, “consisting” and/or “including” when used herein, specify the
presence of stated features, integers, steps, operations, elements and/or components, but do
not preclude the presence or addition of one or more other features, integers, steps,
operations, elements, components and/or groups thereof.

It should also be noted that in some alternative implementations, the functions/acts noted
may occur out of the order noted in the figures. For example, two figures shown in
succession may, in fact, be executed concurrently or may sometimes be executed in the
reverse order, depending upon the functionality/acts involved.
Unless otherwise defined, all terms (including technical and scientific terms) used herein
have the same meaning as commonly understood by one of ordinary skill in the art to which
example embodiments belong. It will be further understood that terms, e.g., those defined
in commonly used dictionaries, should be interpreted as having a meaning that is consistent
with their meaning in the context of the relevant art and will not be interpreted in an idealized
or overly formal sense unless expressly so defined herein.
Embodiments explained herein pertain to arrangement of a power transformer testing with
oil-water assembled cooler. FIG. 1 illustrates a conventional arrangement 100 for cooling
power and rectifier transformer 102. The arrangement 100 is having the power and rectifier
transformer 102, an oil inlet 104, an oil outlet 106 and a water cooler 108. The water cooler
108 is further coupled to a water inlet 110 and a water outlet 112. In an aspect, the water
cooler 108 is an OFWF cooler type.
As can be appreciated by those skilled in the art, the power in the form of electrical energy
is harnessed using the power and rectifier transformer 102. In the process of energy
transportation, wasted energy is manifested in the form of heat energy. As a result, the
temperature of the power and rectifier transformer 102 may increase.
To limit the rise in temperature of the power and rectifier transformer 102 below a certain
specified limit, different means and methods of cooling, say, oil to air radiator cooling, oil
to air integral coolers, oil to water integral coolers, and the like, are used.

For cooling, the power and rectifier transformer 102 is completely submerged with oil.
When the temperature of the power and rectifier transformer 102 increases, the oil
temperature increases and by the process of convection, this oil goes to a top part of the
power and rectifier transformer 102 and then it is taken outside through the water cooler
108.
In the water cooler 108, there are two passages. In one passage, the hot oil is flown through
the oil inlet 104 and the oil outlet 106, while second passage is dedicated to flow of water
through the water inlet 110 to the water cooler 108 and the water outlet 112 from the water
cooler 108. In an aspect, there is a metallic surface between the two passages which transfers
heat from oil to water. In said aspect, the metallic surface is a tubular surface.
In operation, the heat from the power and rectifier transformer 102 generated by virtue of
wasted energy is dissipated (removed) and the temperature of the transformer is kept low as
per requirement by circulating the oil between the power and rectifier transformer 102 and
the water cooler 108.
However, there are two major requirements of water to flow and dissipate the heat. These
two major requirements are water pressure and water volume. Water volume is normally
expressed in terms of LPM (liter per minute) available at site sourced from lake or pond or
river, while water pressure is expressed in psi (pounds per sq. inch ) or kg per sq. cm
available at the source. As can be appreciated by those skilled in the art that the water
pressure is variable, i.e., different pressure is obtained at different site. Since the power and
rectifier transformer 102 is installed for operation at site (FIG. 2), the test conditions at the
manufacturing works of the power and rectifier transformer 102 have to be identical. That

is, in the test plant, condition identical to the site is to be developed for testing of the power
and rectifier transformer 102 as per the site condition.
In one example, at manufacturing works where free flow of water is available at very little
pressure, a water pump 114 (FIG. 3) is connected to the water inlet 110 and the water outlet
112 of the water cooler 108 to adjust the water pressure. The water pump 114 is controlled
to an open position or a closed position as a function of the temperature of either the power
and rectifier transformer 102 or the water cooler 108. However, as mentioned above, the
pump has, as always, few complicacies, power consumption and maintainability issues.
In another example, where site water is available at very high-pressure head and that has to
be reduced down to a level in order to make it suitable for feeding the water cooler 108, a
pressure reducing valve (FIG. 4) is provided in the water pipe whose purpose is to reduce
the pressure of the water entering into the water cooler 108 which is a complicated design.
To this, various embodiments and implements of the present disclosure are proposed herein
to address the issues persisting with the water pipe having a water pump or a pressure
reducing valve. In an embodiment, a system 100 of changing pressure in a water pipe of a
power transformer at site is shown in FIG. 5, in an accordance with an embodiment of the
present disclosure. In said embodiment, at industrial site or any manufacturing plant, water
pressure availability is very high or low, and that needs to be reduced or increased for
making it suitable for the-water cooler 108 of the power and rectifier transformer 102.
As can be seen from FIG. 5, the water pressure could be increased or reduced by employing
a water tank 116. The water tank 116 is installed beneath a water source of the water cooler
108. The water received from the water source is passed through an inlet formed at the top
of the water tank 116 in the form of free-discharge, and is taken out from the water tank 116
from an outlet formed at the bottom of the water tank 116. The size of the inlet and the outlet

of the water tank 116 could be identical and suitable for the volume of water flow required
at the water cooler 108. In an aspect, the level of the water in the water tank 116 is decided
based on the pressure required of the outlet. For instance, when a water pressure of 5
kg/sq.cm is required, the water tank 116 is to be filled up to a level of 5 meter from its base,
and when a water pressure of 0.7 kg/sq.cm is required; the water tank 116 is filled up to a
level of 7.2 meter from its base. Thus, based on the requirement of the water pressure, the
level in the water tank is filled.
FIG. 6 shows a method of changing water pressure in a power and rectifier transformer 102
which are equipped with water cooler 108, in accordance with an embodiment of the present
disclosure. In accordance with the said embodiment, pressure head are set up as LEVEL 1
and LEVEL 2, as shown in FIG. 6. For instance, when a water pressure of 5 kg/sq.cm is
required, the water tank 116 is to be filled up to the LEVEL 2 of 5 meter from its base, and
when a water pressure of 0.7 kg/sq.cm is required; the water tank 116 is filled up to the
LEVEL 1 of 7.2 meter from its base. Thus, based on the requirement of the water pressure,
the level in the water tank is filled.
TECHNICAL ADVANTAGE
The present disclosure proposes a method for changing the water pressure suitable for water
cooled transformer simple, maintenance free, and reliable
The present disclosure proposes a method for changing the water pressure is cost effective
and easy for implementation at works as well as at site.
The present disclosure proposes a method for changing the water pressure, phenomena like
rusting or other chemical interaction owing to operation with water does not affect the
system performance.

The present disclosure proposes a method for changing the water pressure can be made
portable and shifted from place to place as per requirement.
The present disclosure proposes a method for changing the water pressure which can be
repetitively used for different pressure heads for test of different transformer a works, i.e.
one system can be made applicable to different pressure heads as per requirement
The present disclosure proposes a method for changing the water pressure is without
employing any electricity for running of pumps there by reducing cost and improving
availability of the system and transformer.
Furthermore, each of the appended claims defines a separate invention, which for
infringement purposes is recognized as including equivalents to the various elements or
limitations specified in the claims. Depending on the context, all references below to the
“invention” may in some cases refer to certain specific embodiments only. In other cases, it
will be recognized that references to the “invention” will refer to subject matter recited in
one or more, but not necessarily all, of the claims.
Groupings of alternative elements or embodiments of the invention disclosed herein are not
to be construed as limitations. Each group member can be referred to and claimed
individually or in any combination with other members of the group or other elements found
herein. One or more members of a group can be included in, or deleted from, a group for
reasons of convenience and/or patentability. When any such inclusion or deletion occurs,
the specification is herein deemed to contain the group as modified thus fulfilling the written
description of all groups used in the appended claims.

Furthermore, those skilled in the art can appreciate that the terminology used herein is for
the purpose of describing particular embodiments only and is not intended to be limiting of
the present disclosure. It will be appreciated that several of the above-disclosed and other
features and functions, or alternatives thereof, may be combined into other systems or
applications. Various presently unforeseen or unanticipated alternatives, modifications,
variations, or improvements therein may subsequently be made by those skilled in the art
without departing from the scope of the present disclosure as encompassed by the following
claims.
The claims, as originally presented and as they may be amended, encompass variations,
alternatives, modifications, improvements, equivalents, and substantial equivalents of the
embodiments and teachings disclosed herein, including those that are presently unforeseen
or unappreciated, and that, for example, may arise from applicants/patentees and others.
While the foregoing describes various embodiments of the present disclosure, other and
further embodiments of the present disclosure may be devised without departing from the
basic scope thereof. The scope of the present disclosure is determined by the claims that
follow. The present disclosure is not limited to the described embodiments, versions or
examples, which are included to enable a person having ordinary skill in the art to make and
use the invention when combined with information and knowledge available to the person
having ordinary skill in the art.

WE CLAIM:
1. A method for controlling water pressure for harnessing in a water-cooled transformer
(102), the method comprises:
ascertaining a desired water pressure with which the water is to be supplied to a water
inlet (110) of a water cooler (108) coupled to the power and rectifier transformer (102);
and
storing a water tank (116) fluidly connected to the water inlet (110) up to a predefined
level corresponding to the ascertained water pressure, so as to achieve the desired water
pressure.
2. The method as claimed in claim 1, wherein the storing comprises filling the water in
the water tank (116) to one the predefined levels (LEVEL 1, LEVEL 2) to increase or
decrease the water pressure up to the desired water pressure.
3. The method as claimed in claim 1, wherein the water cooler (108) is an oil forced
water forced (OFWF) water cooler.
4. A system for controlling water pressure for harnessing in a water-cooled transformer
(102), the system comprising;
a water cooler (108) for receiving and cooling the oil circulated through an oil inlet
(104) and oil outlet (106) connected to the power and rectifier transformer (102); and
a water tank (116) fluidly connected to a water inlet (110) of the water cooler (108),
wherein the water tank (116) is to store the water up to a predefined level corresponding
to a water pressure with which the water is to be supplied to the water inlet (110), so as
to achieve the desired water pressure;

5. The system as claimed in claim 4, wherein the water tank (116) is filled up to one the
predefined levels (LEVEL 1, LEVEL 2) to increase or decrease the water pressure up
to the desired water pressure.
6. The method as claimed in claim 4, wherein the water cooler (108) is an oil forced
water forced (OFWF) water cooler.