FORM 2
THE PATENTS ACT, 1970 (39 of 1970)
As amended by the Patents (Amendment) Act, 2005
&
The Patents Rules, 2003
As amended by the Patents (Amendment) Rules, 2006
COMPLETE SPECIFICATION
(See section 10 and rule 13)
TITLE OF THE INVENTION
A connecting device for electrically connecting high voltage cables to a power distribution
equipment
APPLICANT
Crompton Greaves Limited, CG House, Dr Annie Besant Road, Worli, Mumbai 400 030,
Maharashtra, India, an Indian Company
INVENTOR
Makvana Dharmesh of Power Transformers Division (TI), Crompton Greaves Ltd, Kanjurmarg, Mumbai-400042, Maharashtra, India, Indian National
PREAMBLE TO THE DESCRIPTION
The following specification particularly describes the invention and the manner in which it is to
be performed:

FIELD OF THE INVENTION
The present invention relates to electrical connecting devices for connecting high
voltage electric cables with power distribution equipments.
DESCRIPTION OF THE BACKGROUND ART
Power distribution apparatuses such as transformers, switchgears must be
connected to incoming and outgoing electric line. To this end, suitable bushings are provided to render the internal windings of the transformer accessible from outside the tank. When the incoming and outgoing electric lines are constituted by overhead lines, they are connected directly to the bushings. The incoming and outgoing electric lines are constituted by electric cables, and the appropriately designed sealing ends of the electric cables must be connected to the bushings of the transformer. Generally, and especially when the operational voltages are very high, this connection is not made in alit, but is surrounded by an insulated medium having high dielectric characteristics. To this end, the sealing end of the cable and that part of the bushing of the transformer which is located outside the tank are enclosed in an appropriate metal box filled with insulating fluid like oil/SF6,
Typically, the connection between electric lines and the bushing is done through
electrical connectors. The electrical connector is in the form of thick solid copper rod for catering voltage requirements of upto 220KV. The connectors are physically connected between the end of the high voltage electric line and the bushing so that electrical linkage is established therebetween. Such arrangement however has several disadvantages that need immediate attention. First, this arrangement is only for catering upto 220KV voltage requirements and in order to cater to higher voltage requirements, the thick size of connector is used which further leads to several disadvantages like increase in size of the cable box and more effective insulating material being used. Second, due to thick size of the solid connector current concentration is mostly on the surface

and not uniformly distributed across the entire body of the connector. Thus, more heat is dissipated by the connector and the cooling is not that effective. Accordingly, in order to negate the heat dissipation, size of the cable is increased so that more insulating fluid could be filled inside. This severely leads to cost disadvantages on part of manufacturers. Insulating the connector is also not an option because in that case the heat will not be dissipated at all leading to further complications.
Thus, there is a need to provide an effective and efficient electrical connection
between the high voltage electric lines and the bushing that could address at least some of the above mentioned drawbacks and yet effectively transfers a variety of high voltage electric current.
SUMMARY OF THE INVENTION
Accordingly disclosed herein is a connecting device for electrically connecting a
high voltage electric cable to a conductor within a cable box filled with an insulating fluid, the cable box including a cable sealing end for insulating an extendable portion of the electric cable and a bushing for insulting the conductor within the cable box, the conductor extendable outside the cable box to be connected to a power distribution equipment,. The connecting device including an electrical connecting member disposed in electrical communication between the high voltage electric cable and the conductor within the cable box. the electrical connecting member including, a first connector end and a second connector end, a plurality of elongated conductive leads tied together to form a single entity and extending between crimped ends, the first connector end coupled with one of the crimped ends and connected to an end of the insulated high voltage cable disposed within the cable sealing end, the second connector end coupled with other of the crimped ends and connected to the insulated conductor within the bushing, the conductor couplable to windings within the power distribution equipment, and a flexible insulator wrapped around the electrical connecting member along its entire length, the insulator dissipating heat generation into the insulating fluid and acting as an electrical insulator.

In some embodiments, the diameter of the electrical connecting member is
26.5mm, and wherein the overall thickness of the insulator wrapped around the crimped plurality of elongated stranded copper leads is 22,5mm.
In some embodiments, two high voltage cables are insertable within the cable box
through a bottom surface thereof, both the high voltage cables disposed within the corresponding cable sealing ends and connected with each other through a first electrical connecting member, and wherein a second electrical connecting member is electrically connected between a middle portion of the first electrical connecting member and the conductor within the cable box.
In some embodiments, a top surface of the cable box has a hole formed therein,
the high voltage cable insertable within the cable box through the hole and electrically connected with the conductor in linear orientation within the cable box.
In some embodiments, a top surface of the cable box includes two holes formed
therein, the two high voltage cables insertable within the cable box through the two holes, ends of each of the high voltage cables connected with each other through a first electrical connecting member, and wherein a second electrical connecting member is electrically connected between a middle portion of the first electrical connecting member and the conductor in linear orientation within the cable box.
It is to be understood that both the foregoing general description and the
following detailed description of the present embodiments of the invention are intended to provide an overview or framework for understanding the nature and character of the invention as it is claimed. The accompanying drawings are included to provide a further understanding of the invention and are incorporated into and constitute a part of this specification. The drawings illustrate various embodiments of the invention and together with the description serve to explain the principles and operation of the invention.

A BRIEF DESCRIPTION OF THE DRAWINGS
The above-mentioned and other features and advantages of the various
embodiments of the invention, and the manner of attaining them, will become more apparent and will be better understood by reference to the accompanying drawings, wherein:
FIG. 1 is front elevational view of a cable box connectable with a power
distribution equipment according to an embodiment of the present invention;
FIG. 2 is front elevational view of an electrical connecting member used within
the cable box of FIG. 1 according to an embodiment of the present invention;
FIG. 3 is a bottom view of the cable box of FIG. 1 having a pair of holes for
inserting at least high voltage electric cables within the cable box according to an embodiment of the present invention;
FIG. 4 is top elevational view of the cable box of FIG. 3;
FIG. 5 is a front elevational view of the cable box having the high voltage electric
cable insertable from the top of the cable box and linearly linked with a conductor according to an embodiment of the present invention;
FIG. 6 is front elevational view of the cable box having atleast two high voltage
electric cables insertable from the top of the cable box and electrically linked with a conductor according to an embodiment of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIG. 1 illustrates a cable box 100 that is preferably mechanically coupled to a
power distribution device (not shown) according to an embodiment of the present invention. The potential difference at the housing of the cable box 100 is kept at a zero potential. The cable box 100 is defined by a top surface 102, a bottom surface 104, and two pairs of opposite sides 106. As

well known, within the cable box 100 the high voltage electric lines are electrically linked to a conducting portion of the power distribution equipment through an electrical connecting member 108. Thus, the cable box 100 is a high electrical stress zone in which substantial heat energy is dissipated by the electrical wires and the connecting member 108. Accordingly, an insulating fluid 110 preferably oil or SF6 for a rating of 132kv & above is used. As illustrated in FIG. 1, the bottom surface 104 of the cable box 100 has a pair of holes (not shown) formed therein. A cable sealing end 112 is positioned on the bottom surface 104 of the cable box 100 such that one of the holes opens within the cable sealing end 112. Further, a bushing 114 is also positioned on the bottom surface 104 of the cable box 100 in such a manner that the other hole opens within the bushing 114. Appropriate drain valves 116 are also connected with the cable box 100 to replenish or to replace the insulating fluid 110 as and when required.
Preferably, a high voltage 132kv & above electric cable 118 is inserted within the
cable box 100 through one of the holes on the bottom surface 104 and positioned within the cable sealing end 112. A conductor 120 that is electrically connected with the power distribution equipment is insertable through the other hole and positioned within the bushing 114. Thus, both the electric cables 118 as well as the conductor 120 are insulated within the cable box 100. As shown in FIG. 1, corresponding ends of the high voltage electric cable 118 and the conductor 120 are suitably interconnected with each other through the electric connecting member 108, noted above. Preferably as shown in FIG. 2, the electric connecting member 108 extends between a first connector end 122 and a second connector end 124. The electrical connecting member 108 is formed from a plurality of elongated conductive leads 126, preferably flexible copper leads, and preferably tied together to form a single entity. Various known methods may be used to tie the plurality of conductive leads 126 and considered to be within the scope of the present invention. The plurality of conductive leads 126 are preferably crimped at its opposite ends 128 so that the conductive leads 126 could be suitably fitted between the first and the second connector ends 122,

124. Alternatively, the ends 128 of the conductive leads 126 may also be brazed to be fitted between the connector ends and considered to be within the scope of the present invention.
As shown in FIGS. 1 and 2, the connecting member 108 and the plurality of
copper leads are fully covered from outside along its entire length by an insulating cover 130 wrapped therearound. The first connector end 122 of the connecting member 108 is suitably connected to the end of the insulated high voltage cable 118 disposed within the cable sealing end 112 in such a manner that no naked electric wire is exposed to the surroundings. This is very important for preventing voltage leakage within the cable box 100. Further, the second connector end 124 of the connecting member 108 is suitably coupled to the insulated conductor 120 within the bushing 114 so that no naked portion of the conductor 120 is exposed within the cable box 100. As seen in FIGS. 1 and 2, the connecting member 108 is slightly bent at both the first and the second ends 122, 124 to be able to connect properly with the high voltage electric cable 118 and the conductor 120, respectively. However, it may not be necessary to bend the ends 122, 124 at all and considered to be within the scope of the present invention. There are several other advantages of the by using the plurality of tied conductive leads 126 for example, instead of solid conductor 120 as used in current arrangements, strained leads 126 give reduction in resistance to current & losses. Further, it also gives the flexibility to the connection. Additionally, it also allows reduction of the electric field strength of the oil at conductor surface will help to increase life of the oil & reduce the possibility of dielectric strength of oil.
As seen in FIG. 2, the plurality of copper rods are kept within the insulating cover
130 is wrapped around the entire length thereof. Preferably, the insulating cover 130 is formed of a flexible material such as creep or kraft paper is compressed. It is to be understood that the insulating cover 130 may also be formed from other flexible materials that serve the purpose of insulating and considered to be within the scope of the present invention. The insulating cover 130 is suitably chosen to perform two functions within the cable box 100. First, the insulating cover 130

prevents the highly conductive copper rods, which carry high voltage power, to be exposed within the cable box 100. This is extremely for ensuring that no additional conductive path that may lead to short circuit is created. Second, the insulating cover 130 allows effective heat dissipation into the insulating fluid 110 present within the cable box 100. It will be appreciated by a skilled person that due to the fact that the plurality of copper rods are tied together, the charge concentration is not on the surface of the rods, as noted with respect to existing electrical connectors. Rather, the charge concentration is uniformly distributed across the entire cross sectional area of the copper rods. As a result of this, heat dissipation is substantially less than prior art pure solid copper rods.
Preferably, the diameter of the electrical connecting member 108 is 26.5 mm
whereas the radial thickness of the insulator wrapped around the crimped plurality of elongated flexible copper leads is 22.5 mm. Such an arrangement provides another benefit that it order to cater to higher ratings of electrical voltage (KV) more radial thickness of insulation wrapped without the need of increasing the size of the cable box 100. This gives a significant advantage over the prior art arrangements to cater higher KVs. In the various embodiments noted above, the arrangement within the cable box 100 is provided by keeping in mind the electrical power ratings of upto 400KV. However, in other embodiments of the present invention, higher electrical power ratings of more than 400KV, for example upto 800 KV or 1200KV, could be easily transferred within the power distribution equipment through the cable box 100 by choosing appropriate electrically insulating fluid within the cable box 100. Accordingly, one way to effectively and efficiently transfer electrical power ratings of 800 KV, 1200KV, or more is to position a plurality of layers of compressed Kraft or creep paper (not shown) suitably held within the cable box 100. Further, between any two of the layers insulating oil or SF6 (not shown) may be securely retained. This arrangement of compressed creep Kraft paper and oil/SF6 acts as a insulating fluid and an insulation with high dia electric strength 110 for dissipating heat energy emanating out of the

electrical connector, high voltage electric cables 118, and the conductor 120 connected to the power distribution equipment.
As noted above in the various embodiments of the present invention, only one
high voltage electric cable 118 is insertable within the cable box 100 that is connected to the conductor 120 couplable to the power distribution equipment. (Give practical application as discussed of this arrangement) However, in other embodiments of the present invention, more than one, for example two, high voltage electric cables 118 may be suitably connected to the conductor 120 within the cable box 100. As shown in FIGS. 3 and 4, the bottom surface 104 of the cable box 100 may have two holes 132 formed therein for inserting two high voltage electric cables 118 and appropriately positioned within their corresponding cable sealing ends 112. The ends of both the high voltage cable ends may be interconnected with each through a first electrical connector. The first electrical connector is same as that of the electrical connecting member 108 described previously in several embodiments. Further, to a preferably, middle portion of the first electrical connecting member, a second electrical connecting member is electrically connected that runs up further to be connected with the conductor 120 within the cable box 100. It is to be understood that the copper leads 126 of the first connecting member and the second connecting member are physically connected to each other by making appropriate provisions within the insulating cover 130s. Thus, from a top view, the connecting device between the two connecting members will be preferably of a C-shape. (Give practical application as discussed of this arrangement)
In another embodiment of the present invention as noted in FIG. 5, the top
surface 102 of the cable box 100 has a hole formed therein. Through this hole, the high voltage cable 118 is insertable within the cable box 100 and electrically connected with the conductor 120. Preferably, the arrangement between the electrical cable 118. the connecting member 108, and the conductor 120 is in linear orientation (I-shape) when looked from a front view of the cable box 100. (Give practical application as discussed of this arrangement ) In yet another embodiment of the

present invention as noted in FIG. 6, the top surface 102 of the cable box 100 includes two holes formed therein. The two high voltage cables 118 insertable within the cable box 100 through the two holes. Further, ends of each of the high voltage cables 118 are connected with each other through a first electrical connecting member 134. Furthermore, a second electrical connecting member 136 is electrically connected between a middle portion of the first electrical connecting member 134 and the conductor 120 in linear orientation within the bushing 114. It is to be understood that the copper leads 126 of the first connecting member 134 and the second connecting member 136 are physically connected to each other by making appropriate provisions within the insulating covers 130. (Give practical application as discussed of this arrangement)
It is to be understood by a skilled person that more than two cables 118 may also
be inserted within the cable box 100 and appropriately connected with one or more conductors 120 leading to various shapes of arrangements within the cable box 100. All such modifications should be considered to be within the scope of the present invention. Further, such arrangements of the high voltage electric cables 118, electrical connecting member 108, and the conductor 120 may be easily applied in various forms of power distribution devices such as transformer, switchgears. etc.
It will be apparent to those skilled in the art that various modifications and
variations can be made to the present invention without departing from the spirit and scope of the invention. Thus it is intended that the present invention cover the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents.

We Claim:
1. A connecting device for electrically connecting a high voltage electric cable to a conductor within a cable box filled with an insulating fluid, the cable box including a cable sealing end for insulating an extendable portion of the electric cable and a bushing for insulting the conductor within the cable box, the conductor extendable outside the cable box to be connected to a power distribution equipment, the connecting device comprising:
an electrical connecting member disposed in electrical communication between the high voltage electric cable and the conductor within the cable box, the electrical connecting member including:
a first connector end and a second connector end;
a plurality of elongated flexible conductive leads tied together to form a single entity and extending between crimped ends, the first connector end coupled with one of the crimped ends and connected to an end of the insulated high voltage cable disposed within the cable sealing end, the second connector end coupled with other of the crimped ends and connected to the insulated conductor within the bushing, the conductor couplable to windings within the power distribution equipment; and
a flexible insulator wrapped around the electrical connecting member along its entire length, the insulator dissipating heat generation into the insulating fluid and acting as an electrical insulator.
2. The connecting device as claimed in claim 1, wherein the diameter of the electrical connecting member is 26.5mm, and wherein the radial thickness of the insulator wrapped around the crimped plurality of elongated flexible copper leads is 22.5mm.

3. The connecting device as claimed in claim 1, wherein the insulating fluid used within the cable box for 220kv rating of high voltage is oil, Sulphur Fluoride (SF6) gas.
4. The connecting device as claimed in claim 1, wherein the insulating fluid used within the cable box for 800kv and above rating of high voltage is a combination of compressed craft or creep paper and oil or Sulphur Fluoride (SF6) arranged together to occupy the available space within the cable box.
5. The connecting device as claimed in claim 1, wherein a bottom surface of the cable box includes a first hole and a second hole formed therein, the high voltage cable insertable within the cable sealing end disposed through the first hole and whereas, the conductor is insertable within the bushing through the second hole.
6. The connecting device as claimed in claim 1, wherein two high voltage cables are insertable within the cable box through a bottom surface thereof, both the high voltage cables disposed within the corresponding cable sealing ends and connected with each other through a first electrical connecting member, and wherein a second electrical connecting member is electrically connected between a middle portion of the first electrical connecting member and the conductor within the cable box.
7. The connecting device as claimed in claim 1, wherein a top surface of the cable box has a hole formed therein, the high voltage cable insertable within the cable box through the hole and electrically connected with the conductor in linear orientation within the cable box.

8. The connecting device as claimed in claim 1, wherein a top surface of the cable box includes two holes formed therein, the two high voltage cables insertable within the cable box through the two holes, ends of each of the high voltage cables connected with each other through a first electrical connecting member, and wherein a second electrical connecting member is electrically connected between a middle portion of the first electrical connecting member and the conductor in linear orientation within the cable box.
9. The connecting device as claimed in claim 1, wherein the insulator is formed of compressed creep or craft paper.
10. The connecting device as claimed in claim 1, wherein each of the elongated conductive leads
is cylindrical in shape and made from copper material.