FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
&
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
(See section 10, rule 13)
1. Title of the invention: NEUTRAL SECTION ASSEMBLY
2. Applicant(s)

NAME NATIONALITY ADDRESS
RAYCHEM RPG PVT. LTD Indian 463, Dr Annie Besant Road, Worli, Mumbai, Maharashtra, India
3. Preamble to the description
COMPLETE SPECIFICATION
The following specification particularly describes the invention and the manner in which it
is to be performed.

TECHNICAL FIELD
[0001] The present subject matter relates, in general, to overhead line equipments. More specifically, the present subject matter relates to a neutral section assembly for isolating or separating different sections of the overhead electricity transmission line.
BACKGROUND
[0002] A neutral section is a portion of the overhead electricity transmission line which may act as insulated phase separating various sections of the overhead line connected to two or more adjacent substations. In general, an electric train engine or electric locomotive may receive electrical power from the overhead lines in which adjacent sections of the overhead line are powered by different substations. It may be noted that, to provide equal loading on all phases of the generated electric power, each substation supplies corresponding section with different phase. The neutral section uses PTFE rods for providing insulation and smooth transition between adjacent contact wire sections, which may degenerate or wears with passage of time and need routine maintenance or replacement.
BRIEF DESCRIPTION OF DRAWINGS
[0003] The features, aspects, and advantages of the present subject matter will be better understood with regards to the following description and accompanying figures. The use of the same reference number in different figures indicate similar or identical features and components. [0004] FIG. 1 provides a schematic of an electricity transmission environment having an overhead electricity transmission line feeding an electric locomotive, in accordance with an embodiment of the present subject matter;

[0005] FIG. 2 illustrates a perspective view of a neutral section
assembly assembled over a catenary wire of an overhead electricity
transmission line, in accordance with an embodiment of the present subject
matter;
[0006] FIG. 3 illustrates a schematic view of the neutral section
assembly comprising the plurality of rollers as rotatable member, in
accordance with an embodiment of the present subject matter;
[0007] FIGS. 4A-4C illustrate a perspective view, a top view and a side
view, respectively, of a neutral section assembly assembled over the
catenary wire of the overhead electricity transmission line, wherein the
neutral section assembly comprises the plurality of rollers as rotatable
member, in accordance with an embodiment of the present subject matter;
[0008] FIG. 4D illustrates an expanded view of a portion of the neutral
section assembly comprising the plurality of rollers as rotatable member, in
accordance with an embodiment of the present subject matter;
[0009] FIGS. 5A-5B illustrate a perspective view and a side view,
respectively, of a neutral section assembly assembled over the catenary
wire of the overhead electricity transmission line, wherein the neutral section
assembly comprises the plurality of rollers and an insulator attached over
the plurality of rollers as rotatable member, in accordance with an
embodiment of the present subject matter;
[0010] FIG. 5C illustrates an expanded view of a portion of the neutral
section assembly comprising the plurality of rollers and an insulator
attached over the plurality of rollers as rotatable member, in accordance
with an embodiment of the present subject matter;
[0011] FIG. 6 illustrates a schematic view of a neutral section assembly
comprising at least two linear strips as rotatable member, in accordance
with an embodiment of the present subject matter;
[0012] FIGS. 7A-7C illustrate a perspective view, a top view and a side
view, respectively, of the neutral section assembly assembled over the
catenary wire of the overhead electricity transmission line, wherein the

neutral section assembly comprises at least two linear strips as rotatable
member, in accordance with an embodiment of the present subject matter;
[0013] FIGS. 8A-8C illustrate a perspective view, top view and a side
view, respectively, of a neutral section assembly assembled over the
catenary wire of the overhead electricity transmission line, wherein the
neutral section assembly comprises at least one conveyor as rotatable
member, in accordance with an embodiment of the present subject matter;
[0014] FIG. 8D illustrates an expanded view of a portion of the neutral
section assembly comprising the at least one conveyor as rotatable
member, in accordance with an embodiment of the present subject matter;
[0015] It may be noted that throughout the drawings, identical
reference numbers designate similar, but not necessarily identical, elements. The figures are not necessarily to scale, and the size of some parts may be exaggerated to more clearly illustrate the example shown. Moreover, the drawings provide examples and/or implementations consistent with the description; however, the description is not limited to the examples and/or implementations provided in the drawings.
DETAILED DESCRIPTION
[0016] As may be understood, with rapid development of high-speed
railways, electrification of the railway network is being carried on at a rapid pace to increase passenger comfort and to reduce operational cost of the railway network. Overhead electricity transmission network or overhead lines are utilized to feed the electric locomotive or other type of electric vehicle used in railways. Such overhead line equipment includes various important parts, one of which is the contact wire which carries the electricity to be supplied to the electric locomotive through a current collecting device known as pantograph. The pantograph is a metallic antenna placed on the carriage of the electric locomotives which is in a close contact with the overhead contact wire and draws the propagating electricity through the contact wire.

[0017] In general, the contact wire of the overhead line equipment is
supplied by a feeder station. As may be generally understood, the feeder station may be a facility next to National Grid electricity transmission line that extracts 25kV and transmits it to the overhead line of the railway via several transmission lines. Due to the wide expanse of the railway network, it is not possible for a single feeder station to feed whole railway lines. Thus, a number of feeder stations are placed with a predefined spacing, such as at every 30-40 km, which maintain average 25kV in the contact wire at each instant of time.
[0018] Generally, the feed provided by such feeder stations is out of
phase with each other so as to provide equal loading on each of the phase of the generated electrical energy. Such change in phase of input power may inadvertently affect the operationality of electric locomotive and may even damage numerous electrical components of the train and the network as well. To avoid such circumstances, neutral sections are deployed. Neutral sections are dead zones in the overhead line, used to isolate sections of contact wire for maintenance purposes and to separate sections of contact wire supplied with feed from different feeder station.
[0019] The neutral sections constitute an electrically insulated or non-
conducting element positioned between sections of the contact wire and fitting overhead catenary wire with insulators. Such neutral sections use polytetrafluoroethylene PTFE rods as an insulator for providing isolation between adjacent contact wire sections. The PTFE rods used in these insulator body have low wear resistance against the movement of pantograph on the underside of the contact wire and provide high friction as well. As the locomotive passes, the pantograph may be dragged across the length of the PTFE rods which, over a period of time, may result in wearing down of these rods. Such wearing of PTFE rods may result in connection loss between the pantograph and the contact wire. Further, exposure of such PTFE rods to drastically changing environmental conditions may result into erosion and even breakage, in some instances.

[0020] Such wearing down of PTFE rods leads to extensive
maintenance and replacement cycle for the neutral section, e.g., around every 3-4 months. PTFE rods are generally circular in cross section. After a number of cycles of pantograph movement along surface of a PTFE rod, the surface of the PTFE rod starts wearing down or gets flattened. When a portion of the surface of the PTFE rod along its circumference gets flattened, the PTFE rod is manually rotated to provide a smooth surface for movement of the pantograph. Depending on the frequency of movement of pantograph, a portion of PTFE rods gets flattened and the PTFE rod is required to be rotated. After, multiple rotation of the PTFE rod, the PTFE rod may have a plurality of surfaces along its length depending on number of rotations. For example, if the PTFE rod is rotated 4 times or 5 times, then the PTFE rod will have four or five surfaces, respectively, along its length and cross section of the PTFE rod becomes rectangular or pentagonal in shape,. The rotation of the PTFE rod is a cumbersome task and incurs maintenance expenditure. Further, the conventional neutral section design tends to also possess higher weight which in turn adds to the efforts and complexity in installation of such neutral sections.
[0021] Examples of a neutral section assembly to electrically isolate
adjacent sections of a contact wire, are described. The neutral section assembly includes a first pair of runners connected to a first contact wire section and a second pair of runners connected to a second contact wire section. In an example, each of the first and second pair of runners are coupled to the respective section of the contact wire using a connector. The pair of runners are such positioned on the contact wire that lower surface of the runners comes in close contact with a pantograph of an electric locomotive.
[0022] In an example, the neutral section assembly further includes a
rotatable member having two ends, to mechanically connect the first contact wire section and the second contact wire section. In an example, the rotatable member is an insulator that electrically isolates the first contact

wire section from the second contact wire section. The length of the rotatable member is designed in such a manner that it provides appropriate insulation to adjacent sections. The first contact wire section and the second contact wire section are the adjacent sections of the overhead line which are supplied by different feeder station having different phase. The rotatable member rotates in relation to a linear movement of the pantograph along the rotatable member. The pantograph gets isolated from the first contact wire section and the second contact wire section as the pantograph leaves the first pair of runners and passes through rotatable member to connect to the second pair of runners. It is pertinent to note that, the first pair of runners connected to the first contact wire section provide a smooth transition for the pantograph to transit from the conducting first contact wire section to the rotatable member and similarly, the second pair of runners connected to the second contact wire section provide smooth transition from the rotatable member to the second contact wire section.
[0023] The present neutral section assembly provide numerous
technical advantages over conventional neutral section. As would be understood that since the rotatable member rotates in relation to a movement of the pantograph, the requirement of the manual rotation of an insulating rod (such as conventional PTFE rod) is obviated. Further, while contacting with the rotatable member, the pantograph experiences less friction as compared to the conventional PTFE rod. Thus, the rotatable member provides higher wear resistance against the movement of the pantograph on the underside of the contact wire as compared to the conventional PTFE material-based rods which wears faster over time. Furthermore, the neutral section assembly reduces maintenance and replacement cycle.
[0024] It may be noted that the above approaches may be performed
using a variety of other mechanisms or components. Such examples are further described in conjunction with FIGS. 1-8C.

[0025] FIG. 1 illustrates an electricity transmission environment 100
involving an overhead electricity transmission line 102 (referred to as overhead line 102) for transmitting electrical energy to an electric locomotive 104, according to an example of the present subject matter. The overhead line 102 is positioned at a certain height above the railway track using mast posts, and corresponding arms. In an example, these mast posts are positioned after a span of 18 to 72m, which may be decided based on the curvature and the structures surrounding the track. In an example, such overhead line 102 constitutes of various components. Examples of such components include, but are not limited to, catenary wire, contact wire, dropper, turnbuckle, and guy wire. The contact wire needs to maintain a near flat profile and to have sufficient weight and tension to limit a pantograph 106 uplift. The contact wire is suspended from the catenary wire by using droppers for making a contact with a pantograph 106 placed on the carriage of the electric locomotive 104. The contact wire material comprises, for example, grooved slid copper or copper alloy.
[0026] In an example, the contact wire of the overhead line 102 supply
the required electricity to the electric locomotive 104 running on the railway network via pantograph 106 or other connecting means. The contact wire contains the alternating current of 25kV provided by the numerous feeder station (not shown in the FIG. 1). The feeder station, as mentioned previously, is a facility next to National Grid electricity transmission line that extracts 25kV of electricity and transmits it to the overhead line equipment 102 of the railway via several transmission means. As explained previously, to provide equal load to all the three phases of the electrical energy receiving from feeder station, numerous feeder station with different electric phase are located on equal distance to feed the corresponding contact wire section. It is difficult to lower the pantograph 106 when such junction of contact wire approaches. A neutral section assembly 108 is placed between the adjacent contact wire sections to isolate these sections. In general, neutral section, such as neutral section assembly 108, is positioned in such

a manner that it maintains a near distance with a traction sub-station (TSS), and a sectioning post (SP). Further, neutral section assembly is placed on the levelled tracks to ensure that the train passes through the neutral section without stopping. In an example, the neutral section assembly 108 may isolate a first contact wire section 110 from a second contact wire section 112.
[0027] In an example, if neutral section assembly 108, is placed
between the adjacent contact wire sections so as to enable all three phases of the electric supply to be utilized. The neutral section assembly 108 isolates the powered sections of different phases.
[0028] In an example, while running on the railway track, the electric
locomotive 104 may initially receive appropriate electrical energy via pantograph 106 placed on the roof of the electric locomotive 104 through the contact wire of the first section 110 and appropriately feed its other components. On approaching other end of the first contact wire section 110, the pantograph 106 may transit itself to the neutral section assembly 108 (whose operation is explained later in conjunction with FIG. 3). Thereafter, the pantograph 106 transits from the neutral section assembly 108 to the second contact wire section 112. In this manner, the neutral section assembly 108 provides isolation of the first contact wire section 110 from the second contact wire section 112. Further constructional and other details of the manner in which the neutral section assembly 108 is assembled on the overhead line 102 is described in detail in conjunction with FIG. 2.
[0029] FIG. 2 illustrates a perspective view of a neutral section
assembly 200 assembled over a catenary wire 208 of an overhead electricity transmission line 102 (as explained in FIG. 1), according to an example of the present subject matter. The neutral section assembly 200 is placed on a contact wire 202 of the overhead electricity transmission line 102 to electrically isolate a first contact wire section 202-1 and a second contact wire section 202-2. In an example, the first contact wire section 202-

1 and the second contact wire section 202-2 are the adjacent sections of
the contact wire 202 of the overhead electricity transmission line 102 which
are supplied by different feeder stations having different phase.
[0030] The neutral section assembly 200 includes a first pair of runners
204-1 connected to the first contact wire section 202-1 and a second pair of runners 204-2 connected to the second contact wire section 202-2. In an example, the first pair of runners 204-1 and the second pair of runners 204-2 are connected to the first contact wire section 202-1 and the second contact wire section 202-2, respectively, through corresponding connectors. The connectors may be splice connectors. In an example, structurally, each runner of the first pair of runners 204-1 and the second pair of runners 204-2 extends towards each other to be connected to the contact wire 202 at one end using the corresponding connector and extends away from each other at the other end to provide running surface for the pantograph 106 (which is shown in FIG. 1) of an electric locomotive 104. In one example, each of the first and second pair of runners 204-1, 204-2 are positioned on the respective section of the contact wire 202 such that the lower surface of the runners comes in close contact with the pantograph 106.
[0031] The neutral section assembly 200 further includes a rotatable
member 206 having two ends, to mechanically connect the first contact wire section 202-1 and the second contact wire section 202-2. In an example, the rotatable member 206 of the neutral section assembly 200 comprises at each end, a connecting element 218 to connect to the respective section of the contact wire 202. In an example, the rotatable member 206 is an insulator that electrically isolates the first contact wire section 202-1 from the second contact wire section 202-2. In an example, the length of the rotatable member 206 is designed in such a manner that it provides appropriate insulation to adjacent sections. The rotatable member 206 rotates in relation to a linear movement of the pantograph 106 along the rotatable member 206. The pantograph 106 gets isolated from the first contact wire section 202-1 and the second contact wire section 202-2 as the

pantograph 106 leaves the first pair of runners 204-1 and passes through
the rotatable member 206 to connect to the second pair of runners 204-2.
Thus, in operation, the first pair of runner 204-1 connected to the first contact
wire section 202-1 provides a smooth transition of the pantograph 106 from
the conducting first contact wire section 202-1 to the insulated rotatable
member 206 and correspondingly, the second pair of runners 204-2 of the
second contact wire section 202-2 provide smooth transition from insulated
rotatable member 206 to the second contact wire section 202-2.
[0032] In one example, each of the first pair of runners 204-1 and the
second pair of runners 204-2 is secured by connecting it with the respective end of the rotatable member 206 to provide stability to the neutral section assembly 200. The connecting element 218 at each end of the rotatable member 206 may be connected to the corresponding pair of runners 204-1, 204-2 in the spacing present between the pair of runners to provide stability to the neutral section assembly 200.
[0033] In operation, the pantograph 106, on its linear movement
against the first contact wire section 202-1 may couple with the first contact wire section 202-1 and get the appropriate feed for the electric locomotive 104. Once the pantograph 106 approaches end point of the first contact wire section 202-1, the pantograph 106 will transit from the first contact wire section 202-1 to the first pair of runners 204-1 of the neutral section assembly 200. In an example, the first pair of runners 204-1 is positioned in such a manner that the underside of the first pair of runners 204-1 provides similar planar surface to the pantograph 106 as provided by the first contact wire section 202-1. Thereafter, the pantograph 106 transits to the rotatable member 206 which electrically isolates the adjacent contact wire sections. The rotatable member 206 rotates with the movement of the pantograph 106. It may be noted that, rotation of the rotatable member 206 may lead to less wearing down of the rotatable member 206, which in turn results in low friction and enhance durability of the neutral section assembly 200.

[0034] Thereafter, the pantograph 106 transits to the second pair of
runners 204-2. Similarly, the pantograph 106 transits to the second contact wire section 204-2 and starts collecting the feed for the electric locomotive 104 and this process is repeated for all junction of the contact wire section. In this manner, the present neutral section assembly 200 provides high wear resistance, less friction, low arching effect, and lesser number of maintenance cycle. Further, it reduces maintenance and replacement cost as well.
[0035] As pantograph 106 moves against the length of the contact wire
202, the contact wire 202 experiences an upward force which may disturb the stability of the contact wire 202 and in certain cases even the pantograph 106 may lose contact with the contact wire 202 as well. Such disconnection of pantograph 106 may result in unwanted arching in the overhead line 102. Such arching may damage other essential components of the overhead line 102. In an example, to avoid such issues, the contact wire 202 is suspended with the catenary wire 208 using a supporting assembly 212.
[0036] The catenary wire 208 connected with the neutral section
assembly 200 further includes a composite insulator 210 for providing insulation effect in the catenary wire 208 as well. In an example, the catenary wire 208 and the contact wire 202 may be mounted on a certain height above the railway track using the mast post (not shown in FIG. 2). The mast post may further use various components for holding, auto-tensioning and height adjustment of these wires.
[0037] In an example, a supporting assembly 212 is mounted at each
end of the neutral section assembly 200. The neutral section assembly 200 is held by the overhead catenary wire 208 using corresponding supporting assemblies 212 connected to the respective end of the neutral section assembly 200. Each of the supporting assemblies 212 comprises a turnbuckle 214 and a guy wire 216 connected end to end to support the neutral section assembly 200. The turnbuckle 214 is a triangular component and consists of two threaded eye bolts, one with a right-hand thread and

other with a left-hand thread to connect the guy wire 216 with left-hand thread and the right-hand thread, respectively. The turnbuckle 214 may be placed on the connecting element 218 of the rotatable member 206 of the neutral section assembly 200 via bolts or by using other means. The guy wire 216 is a flexible string which holds the turnbuckle 214 in place with the catenary wire 208. In an example, the guy wire 216, via hooks or other suspension means, may help in suspending the neutral section assembly 200 in place and even helps in adjusting height of the neutral section assembly 200 as well. Both ends of the guy wire 216 are connected to pair of ends, i.e., the left-hand thread and the right-hand thread of the turnbuckle 214 to stably position the neutral section assembly 200. In this manner, the neutral section assembly 200 is assembled on the contact wire 202 to stably isolate the adjacent contact wire sections.
[0038] In an example, an arc horn 220 is also attached to each runner
in each pair of runners 204-1, 204-2 to extinguish any arcing or excess current. The arc horn 220 may be attached to an end of the runner which extends away from the opposite runner in the respective pair of runners 204-1, 204-2.
[0039] In an example implementation of the present subject matter, the
rotatable member 206 comprises a plurality of rollers 302, such that the pantograph 106 makes contact with the plurality of rollers 302 as the pantograph 106 moves along the rotatable member 206.
[0040] Figure 3 illustrates a schematic view of the neutral section
assembly 200 comprising a plurality of rollers 302 as rotatable members
206. In the illustrated embodiment, the rotatable member 206 comprises the
plurality of rollers 302 arranged in at least one row between two straight rods
304 such that the pantograph 106 makes contact with the plurality of rollers
302 as the pantograph 106 moves along the rotatable member 206. The at
least one row may be arranged vertically between the two rods 304.
[0041] In an example, plurality of rollers 302 may be arranged in a
matrix configuration between the two rods 304 running in parallel, wherein

three rollers in a row may be followed by two rollers alternately such that the
two rollers following the three rollers may be inserted between the three
rollers. In another example, the size of rollers in the rows having three rollers
may be bigger than the size of rollers in the rows having two rollers, i.e., set
of bigger rollers may be followed by the set of smaller rollers. The rollers
302 may be made of insulated material such as the PTFE, for example.
[0042] In operation, when the pantograph 106 moves along the
rotatable member 206, i.e., along the plurality of rollers 302, the rollers 302 rotates in relation to the linear movement of the pantograph 106. As the moving pantograph 106 passes from the first pair of runners 204-1 to the second pair of runners 204-2 via rollers 302, it gets disconnected with the first feeder station and isolates itself with the rollers 302 and connects with the next feeder station using the second pair of runners 204-2. Use of rollers 302 as an insulating rotatable member 206 reduces a contact area of the pantograph 106 with the insulators as compared to the conventional PTFE rods, which are less resistant to wear and requires periodic manual rotation of the rods after surface of the rods gets rough or damaged. Since rollers 302 automatically moves along the moving pantograph 106, no frequent human intervention is required for periodic rotation of the rods and hence the maintenance is easy. Further, due to the rotation of rollers 302, insulating rotating member 206 experiences significantly less wear since rolling friction is lower than the static friction that is experienced in the contact that the pantograph 106 makes with the neutral section assembly 200 in the conventional arrangements.
[0043] FIGS. 4A-4C illustrate a perspective view, a top view and a side
view, respectively, of the neutral section assembly 200 assembled over the catenary wire 208 of the overhead electricity transmission line, wherein the neutral section assembly 200 comprises the plurality of rollers 302 as rotatable member 206, according to an example of the present subject matter.

[0044] FIG. 4D illustrates an expanded view of a portion of the neutral
section assembly 200 comprising the plurality of rollers 302 as rotatable member 206.
[0045] In another example implementation of the present subject
matter, the rotatable member 206 comprising the plurality of rollers 302 also includes an insulator 502 attached over plurality of rollers 302 through intermediate connectors 504. FIGS. 5A-5B illustrate a perspective view and a side view, respectively, of a neutral section assembly 200 assembled over the catenary wire 208 of the overhead electricity transmission line, wherein the neutral section assembly 200 comprises the plurality of rollers 302 and an insulator 502 attached over the plurality of rollers 302 as rotatable member 206, according to an example of the present subject matter. In such arrangement, the number of rows comprising the plurality of rollers 302 as described above may be less. That is, the length of the matrix of rollers 302 may be made shorter than the above configuration, wherein rotatable member 206 comprises a plurality of rollers 302. The insulator 502 is supported by two intermediate connectors 504 and each end of the insulator 502 is connected to respective ends of the rotatable member 206. Each intermediate connector 504 is connected with the contact wire 202 through the connecting element 218 that connects the rotatable member 206 to the respective section of the contact wire 202. In an example, the arrangement of plurality of rollers 302 may be fixedly connected with the intermediate connectors 504 and the insulator 502 is supported by the intermediate connectors 504. While, in another example, the insulator 502 is rigidly fixed, and plurality of rollers 302 are being supported by an intermediate connector 504.
[0046] As the moving pantograph 106 transits from the first pair of
runners 204-1 to the rotatable member 206 comprising the plurality of rollers 302 with an insulator 502 connected over the rollers 302, power from the first feeder station gets disconnected. After the pantograph 106 leaves the rotatable member 206, it starts moving along the second pair of runners

204-2. Further, when the pantograph 106 transits to the second contact wire section 202-2, it starts collecting feed for the locomotive 104 from the next feeder station. Because of the use of an additional insulator 504, the electrical clearances between the first contact wire section 202-1 and the second contact wire section 202-2 can be maintained despite the short length of the insulating rotatable member 206.
[0047] FIG. 5C illustrates an expanded view of a portion of the neutral
section assembly 200 comprising the plurality of rollers 302 and an insulator
502 attached over the plurality of rollers 302 as rotatable member 206.
[0048] In an example implementation of the present subject matter,
the rotatable member 206 comprises at least two linear strips 602 having a rectangular cross section, wherein each of the at least two linear strips 602 rotates with an angle of 180º during the linear movement of the pantograph 106 along the rotatable member 206. Figure 6 illustrates a schematic view of the neutral section assembly 200 comprising at least two linear strips 602 as rotatable member 206. In an example, each end of each of the at least two linear strips 602 is flat and parallel to the pantograph 106. Further, each of the at least two linear strips 602 is twisted by an angle of 180º along the length of the respective strip. In another example, each of the at least two linear strips 602 is made of a material having high mechanical strength with a coating of insulated material. For example, the strips 602 may be made of FRP or nylon 66 or any other equivalent material having high mechanical strength with a coating of insulating material such as PTFE. In an example, each end of the two the linear strips 602 is connected with the corresponding contact wire section through the connecting element 218 of the rotating member 206 with the support of bearings. Bearings at end fittings of the linear strips 602 facilitates the rotation of the at least two linear strips 602 by an angle of 180º. Further, flat ends of the linear strips 602 which are also parallel to the moving pantograph 106, ensures the smooth transition and movement of the pantograph 106 to and from the linear strips 602.

[0049] Since, the linear strips 602 undergoes a 180 degree twist with
the linear movement of the pantograph 106 along the strips 602, another surface of the respective strip will be available for the next cycle of pantograph 106 movement. This obviates the need to manually rotate the strip 602 after a particular surface of the strip becomes rough or gets damaged because of the movement of the pantograph 106.
[0050] FIGS. 7A-7C illustrate a perspective view, a top view and a side
view, respectively, of the neutral section assembly 200 assembled over the catenary wire 208 of the overhead electricity transmission line, wherein the neutral section assembly 200 comprises at least two linear strips 602 as rotatable member 206, according to an example of the present subject matter.
[0051] In an example implementation of the present subject matter, the
rotatable member 206 comprises at least one conveyor 802 placed in at least one row between two rods 804 such that the pantograph 106 is to make contact with the at least one conveyor 802 as pantograph 106 moves along the rotatable member 106. FIGS. 8A-8C illustrate a perspective view, top view and a side view respectively of a neutral section assembly 200 assembled over the catenary wire 208 of the overhead electricity transmission line, wherein the neutral section assembly 200 comprises at least one conveyor 802 as rotatable member 206, according to an example of the present subject matter. In an example, each of the at least one conveyor 802 is placed in the at least one row between the two rods 804 on at least three bearing rods 806. In an example, the at least one conveyor 802 is made of insulated material.
[0052] The at least one conveyor 802 is segmented in at least one row
between the two rods 804 such that each of the conveyor 802 is supported on three bearing rods 806. In operation, when the pantograph 106 makes contact with the at least one conveyor 802 during its movement, the conveyors 802 rotates in relation to the linear movement of the pantograph 106. The bearing rods 806 facilitates the rotation of respective conveyor 802

along the movement of the pantograph 106. As the moving pantograph 106 passes from the first pair of runners 204-1 to the second pair of runners 204-2 via conveyors 802, it gets disconnected with the first feeder station and isolates itself with the conveyors 802 and connects with the next feeder station using the second pair of runners 204-2. Use of conveyors 802 as an insulating rotatable member 206 reduces wear of the insulators as compared to the conventional PTFE rods, which are less resistant to wear and requires periodic manual rotation of the rods after surface of the rods gets rough or damaged. Since conveyors 802 automatically rotates along the moving pantograph 106, no human intervention is required for periodic rotation of the rods and hence the maintenance is easy.
[0053] FIG. 8D illustrates an expanded view of a portion of a neutral
section assembly 200 comprising the at least one conveyor 802 as rotatable member 206.
[0054] Although examples for the present disclosure have been
described in language specific to structural features, it is to be understood that the appended claims are not necessarily limited to the specific features described in the specification. Rather, the specific features are disclosed and explained as examples of the present disclosure.

I/We Claim:
1. A neutral section assembly 200 to electrically isolate a first contact
wire section 202-1 and a second contact wire section 202-2 of an overhead
electricity transmission line 102, the neutral section assembly 200
comprising:
a first pair of runners 204-1 connected to the first contact wire section 202-1 and a second pair of runners 204-2 connected to the second contact wire section 202-2;
a rotatable member 206 having two ends, to mechanically connect the first contact wire section 202-1 and the second contact wire section 202-2,
wherein the rotatable member 206 is to rotate in relation to a linear movement of a pantograph 106 along the rotatable member 206, and
wherein the pantograph 106 gets isolated from the first contact wire section 202-1 and the second contact wire section 202-2 as the pantograph 106 leaves the first pair of runners 204-1 and passes through rotatable member 206 to connect to the second pair of runners 204-2.
2. The neutral section assembly 200 as claimed in claim 1, wherein the first pair of runners 204-1 and the second pair of runners 204-2 are connected to the first contact wire section 202-1 and the second contact wire section 202-2 respectively through corresponding connectors 218.
3. The neutral section assembly 200 as claimed in claim 2, wherein each of the first pair of runners 204-1 and the second pair of runners 204-2 is secured by connecting it with the respective end of the rotatable member 206 to provide stability to the neutral section assembly 200 and wherein each runner of the first pair of runners 204-1 and the second pair of runners 204-2 extends towards each other to be connected to the contact wire 202

at one end using the corresponding connector 218 and extends away from each other at other end to provide running surface for the pantograph 106.
4. The neutral section assembly 200 as claimed in claim 1, wherein the rotatable member 206 comprises a plurality of rollers 302 arranged in at least one row between two straight rods 304 such that the pantograph 106 is to make contact with the plurality of rollers 302 as the pantograph 106 moves along the rotatable member 206.
5. The neutral section assembly 200 as claimed in any one of the preceding claims, wherein the rotatable member 200 comprises an insulator 502 attached over the plurality of rollers 302 through intermediate connectors 504.
6. The neutral section assembly 200 as claimed in any one of the preceding claims, wherein the plurality of rollers 302 is made of insulated material.
7. The neutral section assembly 200 as claimed in claim 1, wherein the rotatable member 206 comprises at least two linear strips 602 having a rectangular cross section, each of the at least two linear strips 602 is to rotate with an angle of 180º during the linear movement of the pantograph 106 along the rotatable member 206.
8. The neutral section assembly 200 as claimed in claim 7, wherein each end of the at least two linear strips 602 is flat and parallel to the pantograph 106, each of the at least two linear strips 602 is twisted by an angle of 180º along a length of the strip 602.

9. The neutral section assembly 200 as claimed in claim 8, wherein each of the linear strips 602 is made of a material having high mechanical strength with a coating of insulated material.
10. The neutral section assembly 200 as claimed in claim 9, wherein the material comprises FRP and nylon 66.
11. The neutral section assembly 200 as claimed in claim 1, wherein the rotatable member 206 comprises at least one conveyor 802 placed in at least one row between two rods 804 such that the pantograph 106 is to make contact with the at least one conveyor 802 as the pantograph 106 moves along the rotatable member 206.
12. The neutral section assembly 200 as claimed in claim 11, wherein each of the at least one conveyor 802 is placed in the at least one row between the two rods 804 on at least three bearing rods 806.
13. The neutral section assembly 200 as claimed in claim 12, wherein the at least one conveyor 802 is made of insulated material.