TECHNICAL FIELD
[001] The subject matter in general relates to current transformers. More
particularly, but not exclusively, the subject matter relates to providing a sealing system for current transformers.
BACKGROUND OF INVENTION
[002] 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.
[003] A current transformer (CT) is an instrument that is used to measure AC
current. It produce an alternating current (AC) in its secondary which is proportional to the AC current in its primary. When the current to be measured in a circuit is too high to measure directly or the system voltage of the circuit is too high, a current transformer can be used to provide an isolated lower current in its secondary side which is proportional to the current in the primary circuit. The current available in secondary side is then suitable for measuring instruments or processing in electronic equipment. Application wise CT is classified into “Protection and Metering” class.
[004] The current transformer is a very critical equipment of power system.
Its proper functioning is so important that even a minute malfunction leads to catastrophe in the switchyard. If the input signal is not transformed properly in the secondary side then protection of the switchyard equipments will be compromised. Even in normal operation of metering, CT will not give proper results.
[005] The 400kV CTs are hermetically sealed units, and are suitable for
outdoor use. The steel tank supports the primary winding which passes through the porcelain housing to terminals in top chamber (i.e., flanges of the porcelain insulator are bolted to the bottom tank and top chamber of the CT). The primary winding is linked with ring type cores having independent secondary windings

connected to secondary terminals in a terminal box on the tank side. The whole assembly forms a common space for oil and is sealed from the atmosphere, the top chamber serving as an expansion chamber. The space above the oil is filled with nitrogen which acts as a cushion for changes in oil volume due to temperature variation.
[006] The 400kV current transformer is an out-door equipment and should be
hermetically sealed. The leakage in sealing will lead to deterioration of oil and ultimately its performance and life will be affected. To keep the current transformer hermetically sealed nitrogen gas is filled in current transformer as per below details:

[007] A sealing arrangement of gasket and aluminum cap was used to retain
the pressure inside the current transformer. But over the time pressure in current transformer gets reduced due to leakage in the sealing arrangement.
[008] Nitrogen gas cushion was used above the transformer oil to take care of
expansion and contraction of oil due to variation of temperature. Over the period of time this gas gets leaked from the current transformer which causes ingression of moisture in the CT and deteriorate the insulating oil and hence the life of current transformer gets reduced.
OBJECT OF INVENTION
[009] 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.
[0010] It is an object of the present disclosure to provide a non-returning valve

(NRV) assembly for sealing a current transformer.
[0011] It is an object of the present disclosure to provide a non-returning valve
(NRV) assembly that prevents the leakage of gas from the current transformer.
[001] 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 OF INVENTION
[0012] This summary is provided to introduce concepts related to providing a
sealing system for a current 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.
[0013] The present disclosure relates to a non-returning valve (NRV) assembly
for sealing a current transformer. The non-returning valve assembly comprises an NRV flange, an NRV cap, an aluminium alloy cap and an NRV Plate. The NRV flange is configured to be in contact with a current transformer. The NRV cap and the NRV Plate are configured to affix the NRV assembly to the current transformer. The aluminium alloy cap is configured to surround the NRV cap. The aluminium alloy cap is configured to seal the current transformer.
[0014] 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
[0015] 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:
[0016] FIG. 1 discloses a non-returning valve (NRV) assembly 100 for sealing
a current transformer 500, in accordance with an embodiment;
[0017] FIG. 2 discloses an aluminium alloy cap 106 of the NRV assembly 100,
in accordance with an embodiment;
[0018] FIG. 3 is a section view of the aluminium alloy cap 106, in accordance
with an embodiment;
[0019] FIG. 4 discloses a plate 108 of the NRV assembly 100, in accordance
with an embodiment; and
[0020] FIG. 5 discloses the application of the NRV assembly 100 to the current
transformer 500, in accordance with an embodiment.
[0021] The figures depict embodiments of the present subject matter for the
purposes of illustration only. A person skilled in the art will easily recognize from the following description that alternative embodiments of the structures and methods illustrated herein may be employed without departing from the principles of the disclosure described herein.
DETAILED DESCRIPTION OF INVENTION
[0022] 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.
[0023] 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.
[0024] 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.
[0025] 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.
[0026] In addition, the descriptions of "first", "second", “third”, and the like in
the present invention are used for the purpose of description only, and are not to be construed as indicating or implying their relative importance or implicitly indicating the number of technical features indicated. Thus, features defining "first" and "second" may include at least one of the features, either explicitly or implicitly.

[0027] 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.
[0028] Referring to FIG. 1 disclosed is a non-returning valve (NRV) assembly
100 for sealing a current transformer 500. The non-returning valve assembly 100 comprises an NRV flange 102, an NRV cap 104 and an aluminium alloy cap 106.
[0029] The NRV flange 102 is configured to be in contact with the current
transformer 500. The NRV flange 102 is placed on the top chamber of the current transformer 500.
[0030] In an embodiment, the top chamber of the current transformer 500 is
the chamber that houses the oil along with an inert gas, such as Nitrogen gas to provide a cushioning effect to the oil during its expansion and contraction of oil.
[0031] In an embodiment, the object of the NRV assembly 100 is to provide a
leak proof sealing to the top chamber of the current transformer 500.
[0032] The NRV cap 104 is configured to affix the NRV assembly 100 to the
top chamber of the current transformer 500 using conventional mechanical jigs and fixtures, such as screws, washers 110, nut 112 and bolts, among others.
[0033] Referring to FIG. 2 and 3, the aluminium alloy cap 106 is configured
to surround the NRV cap 104, such that the aluminium alloy cap 106 seals the current transformer 500. In an embodiment, the aluminium alloy cap 106 has hat-shaped cross section.
[0034] Referring to FIG. 4, disclosed is a plate 108 configured to cover top
portion of the aluminium alloy cap 106. In an embodiment, the plate 108 is circular

in shape.
[0035] FIG. 5 discloses the application of the NRV assembly 100 to the current
transformer 500. As seen in FIG. 5, the NRV assembly 100 is attached to the top portion of the current transformer 500.
[0036] In an embodiment, the current transformer 500 is a 400kV current
transformer.
TECHNICAL ADVANTAGE
[0037] The present disclosure proposes a non-returning valve (NRV) assembly
for sealing a current transformer.
[0038] The present disclosure proposes a non-returning valve (NRV) assembly
that prevents the leakage of gas from the current transformer.
[0039] 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.
[0040] 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.

[0041] 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.
[0042] 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.
[0043] 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 non-returning valve (NRV) assembly (100) for sealing a current
transformer (500), the non-returning valve assembly (100) comprising:
an NRV flange (102) configured to be in contact with a current transformer
(500);
an NRV cap (104) and an NRV Plate (108) configured to affix the NRV
assembly (100) to the current transformer (500); and
an aluminium alloy cap (106) configured to surround the NRV cap (104),
wherein the aluminium alloy cap (106) seals the current transformer (500).
2. The NRV assembly (100) as claimed in claim 1, wherein the NRV cap (104), NRV Plate (108) and the aluminium alloy cap (106) are configured to cover top portion of the current transformer (500).
3. The NRV assembly (100) as claimed in claims 1-2, wherein the current transformer (500) is 400kV current transformer.
4. The NRV assembly (100) as claimed in claims 1-3, wherein the current transformer (500) is any current transformer above 132kV.


5. The NRV assembly (100) as claimed in claims 1-4, wherein the NRV
cap (104