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. Applicants)

NAME NATIONALITY ADDRESS
RAYCHEM RPG PVT. LTD Indian RPG House 463, Dr Annie Besant Road, Worli, Mumbai, Maharashtra 400030, 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
equipment. 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 by 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 an illustration of an electricity transmission
environment having an overhead electricity transmission line feeding an electric locomotive, as per one example;

[0005] FIG. 2 depicts a perspective view of an assembled neutral
section assembly over a catenary wire of an overhead line, as per one example;
[0006] FIG. 3A-B depicts perspective and side views of a neutral
section assembly, as per one example;
[0007] 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
[0008] 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 line is being 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 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.
[0009] 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. That’s

why 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.
[0010] 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.
[0011] 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 PTFE rods as an insulator for providing isolation between adjacent contact wire sections. The PTFE rod 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.
[0012] Such wearing down of PTFE rods leads to extensive
maintenance and replacement cycle for the neutral section, e.g., around every 3-4 months. 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.

[0013] Examples of a neutral section assembly for isolating adjacent
sections of a contact wire, are described. The neutral section assembly includes an insulator assembly for isolating a first contact wire section from a second contact wire section of the overhead electricity transmission lines. In an example, the length of the insulator assembly is designed in such a manner that it provides appropriate insulation to adjacent sections. In an example, 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.
[0014] The insulator assembly further includes a first composite
insulator which is being connected to the first contact wire section and a second composite insulator connected to the second contact wire section. In an example, these composite insulators separate the adjacent contact wire section without allowing the current to pass through the insulator. The insulator assembly may further include an intermediate contact wire section. The intermediate contact wire section may act as a dead zone with no electrification to provide an isolation path between the first composite insulator and the second composite insulator. In an example, one end of the intermediate contact wire section is connected to the first composite insulator and the other end is connected to the second composite insulator to form a continuous insulator assembly. In one example, the intermediate contact wire section is composed of one of a cold-drawn copper, and a copper alloy, such as copper-silver, and copper-tin.
[0015] In an example, the neutral section assembly may further include
a pair of runners for connected to the first contact wire section and the second contact wire section. The pair of runners are coupled to the contact wire of each adjacent sections using a connecting clamp. In an example, the pair of runners are such positioned on the contact wire that the lower surface of the runners comes in close contact with the pantograph of the electric locomotive. It is pertinent to note that, the runners connected to the first contact wire section provide a smooth transition for the pantograph to

transit from the conducting first conduct wire section to the insulated intermediated contact wire section and similarly, the runners of the second contact wire section provide smooth transition from insulated intermediate contact wire section to the second contact wire section.
[0016] In another example, the insulator assembly may further include
a first connecting block and a second connecting block for each of the
composite insulator. The first connecting block is a connection point
between the contact wire section with either of the composite insulator. On
the other hand, the second connecting block is a connection point between
the intermediate contact wire section and first composite insulator or second
composite insulator. In an example, the first connecting block of each
composite insulator may be connected to the corresponding pair of runners
in spacing between the runners to provide stability to the insulator assembly.
[0017] The present neutral section assembly provide numerous
technical advantages over conventional neutral section. As would be understood that the intermediate contact wire section 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. Further, while contacting with intermediate contact wire section pantograph experiences less friction as compared to the conventional PTFE rod. Furthermore, the neutral section assembly reduces maintenance and replacement cycle as well. 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. 1-3.
[0018] 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. In an example, 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 one of a grooved slid copper or copper alloy.
[0019] 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 which is being provided by the numerous feeder station (not shown in the FIG. 1). The feeder station 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. As a normal practice, it is difficult to lower the pantograph 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 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.

[0020] 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
[0021] For 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 to 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 manner in which the neutral section assembly 108 is assembled on the overhead line 102 is further described in detail in conjunction with FIG. 2.
[0022] FIG. 2 illustrates a perspective view of an assembled neutral
section assembly 200 over a catenary wire 202 of an overhead 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 204 of the overhead line equipment 102 to isolate contact wire sections. As pantograph 106 (which is shown in FIG. 1) rubbed against the length of the contact wire 204, the contact wire 204 experiences an upward force which may disturbs the stability of the contact wire 204 and in certain cases even the pantograph may lose contact with the contact wire 204 as well. Such disconnection of pantograph may result in unwanted arching in the overhead line. In an example, such arching may damage other essential components of the overhead line.

[0023] To avoid such issues, the contact wire 204 is suspended with
the catenary wire 202 using a supporting assembly 206. The catenary wire 202 connected with the neutral section assembly 200 further includes a composite insulator 208 for providing insulation effect in the catenary wire 202 as well. In an example, the catenary wire 202 and the contact wire 204 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.
[0024] The supporting assembly 206 further include a turnbuckle 210,
and a guy wire 212. The turnbuckle 210 is a triangular component which may be placed on the top of the connecting blocks of the neutral section assembly 200 via bolts or by using other means. In an example, the turnbuckle 210 is placed on each of the connecting block (explained later in conjunction with FIG. 3) of the neutral section assembly 200. The guy wire 212 is a flexible string which holds the turnbuckle 210 in place with the catenary wire 202. In an example, the guy wire 212 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 212 is connected to the pair of ends of the turnbuckle 210 to stably position the neutral section assembly 200. In this manner, the neutral section assembly 200 is assembled on the contact wire 206 to stably isolate the adjacent contact wire sections. The structural features of the neutral section assembly 200 is further described in detail in conjunction with FIG. 3A-B.
[0025] FIG. 3A-B illustrates perspective and side views of a neutral
section assembly 300(referred to as an assembly 300), according to an example of the present subject matter. The assembly 300 includes an insulator assembly 302 for isolating adjacent contact wire section of the overhead line 102 (as illustrated in FIG. 1). The insulator assembly 302 includes a first composite insulator 304 and a second composite insulator

306. In an example, the first composite insulator 304 is connected to the first contact wire section 308 and the second composite insulator 306 is connected to the second contact wire section 310. In an example, the first contact wire section 308 and the second contact wire section 310 are the adjacent sections of the contact wire of the overhead line equipment which are supplied by different feeder station having different phase. In an example, these composite insulators separate the adjacent contact wire section without allowing the current to pass through the insulator. Further, the composite insulator is of a material comprised of a non-metallic core, and a silicon rubber housing.
[0026] The insulator assembly 302 may further include an intermediate
contact wire section 312. The intermediate contact wire section 312 is used to connect first composite insulator 304 with the second composite insulator 306. In an example, one end of the intermediate contact wire section 312 is connected to the first composite insulator 304 and the other end is connected to the second composite insulator 306. In one example, the intermediate contact wire section 312 may include a pair of parallelly separated contact wires having high wear resistance capability against the movement of pantograph. The intermediate contact wire section 312 is composed of one of a hard-drawn copper, or copper alloy such as mixture of copper and silver, and mixture of copper and tin. As would be appreciated, the wire used in intermediate contact wire section 312 is of the same material as that of the contact wire used in the overhead lines for electricity transmission. So, by using such wire, the problem of low wear resistance and high movement friction of conventional PTFE rods is addressed efficiently.
[0027] The assembly 300 may further include a first pair of runners 314
and a second pair of runners 316 (collectively referred to as pair of runners 314, 316) connected to the first contact wire section 308 and the second contact wire section 310, respectively. The pair of runners 314, 316 uses a connecting clamp 318 for accomplishing a connection with the adjacent

contact wire section. In an example, structurally, the pair of runners 314, 316 extends towards each other to be connected to the first or second contact wire at one end using connecting clamp 318 and extends away from each other at the other end to provide running surface for the locomotive pantograph. In one example, the pair of runners 314, 316 are such positioned on the contact wire that the lower surface of the runners comes in close contact with the pantograph of the electric locomotive. It is pertinent to note that, the first pair of runner 314 connected to the first contact wire section 308 provide a smooth transition of the pantograph from the conducting first conduct wire section 308 to the insulated intermediated contact wire section 312 and correspondingly, the second pair of runners 316 of the second contact wire section 310 provide smooth transition from insulated intermediate contact wire section 312 to the second contact wire section 310.
[0028] In an example, the insulator assembly may further include a first
connection block 320 and a second connecting block 322 for each of the composite insulator. The first connecting block 320 is a connection point between either of the contact wire section (308, 310) with either of the composite insulator (304, 306). On the other hand, the second connecting block 322 is a connection point between the intermediate contact wire section 312 and first composite insulator 304 or second composite insulator 306. In an example, the connecting blocks (320, 322) may further include a connector for establishing high strength connection with the corresponding contact wire sections, i.e., first contact wire section 308, intermediate contact wire section 312, and second contact wire section 310. In one example, the first connecting block 320 of each composite insulator may be connected to the corresponding pair of runners 314, 316 in the spacing present between the pair of runners to provide stability to the insulator assembly 302.
[0029] In operation, the pantograph, on rubbing against the first contact
wire section 308 may couple with the first contact wire section 308 and get

the appropriate feed for the electric locomotive. Once the pantograph approaches end point of the first contact wire section 308, the pantograph will transit from the first contact wire section 308 to the first pair of runners 314 of the assembly 300. In an example, the first pair of runners 314 is positioned in such a manner that the underside of the first pair of runners 314 will provide similar planar surface to the pantograph as provided by the first contact wire section 308. Thereafter, the pantograph will transit to the intermediate contact wire section 312 which is electrically isolated from the adjacent contact wire sections. This isolation is provided by the first and the second composite insulators 304, 306. It may be noted that, higher wear resistance of the intermediate contact wire section 312 may lead to less wearing down of this section, which in turn result in low friction.
[0030] Thereafter, the pantograph, moves further on the intermediate
contact wire section 312 and transits to the second pair of runners 316. Similarly, the pantograph transits to the second contact wire section 310 and this process is repeated for all junction of the contact wire section. In this manner, the present assembly 300 provides high wear resistance, less friction, low arching effect, and lesser number of maintenance cycle. Further, reduces maintenance and replacement cost as well.
[0031] 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 (300) for isolating a first contact wire
(308) section from a second contact wire section (310) of an overhead
electricity transmission line, wherein the neutral section assembly (300)
comprises:
an insulator assembly (302) for isolating the first contact wire section (308) from the second contact wire section (310), wherein the insulator assembly (302) comprises:
a first composite insulator (304) connected to the first contact wire section (308) and a second composite insulator (306) connected to the second contact wire section (310);
an intermediate contact wire section (312), wherein the intermediate contact wire section (312) connects first composite insulator (304) with the second composite insulator (306) by connecting to first composite insulator (304) at one end and second composite insulator (306) on other;
a first pair of runners (314) connected to the first contact wire section (308) and a second pair of runners (316), wherein the pair of runners (314, 316) is connected to each contact wire section using a connecting clamp (318).
2. The neutral section assembly (300) as claimed in claim 1, wherein the intermediate contact wire section (312) includes a pair of parallelly separated contact wires having high wear resistance capability against the movement of locomotive pantograph through it.
3. The neutral section assembly (300) as claimed in claim 2, wherein the contact wire used on overhead line and in intermediate contact wire section (312) is composed of one of a hard-drawn copper, and a copper alloy.

4. The neutral section assembly (300) as claimed in claim 1, wherein the insulator assembly (302) further comprises a first connecting block (320) and a second connecting block (322) for each composite insulator.
5. The neutral section assembly (300) as claimed in claim 4, wherein the first connecting block (320) is a connecting point between contact wire of first section or second section with the first composite insulator (304) or second composite insulator (306).
6. The neutral section assembly (300) as claimed in claim 4, wherein the second connecting block (322) is a connecting point between intermediate contact wire section (312) and first composite insulator (304) or second composite insulator (306).
7. The neutral section assembly (300) as claimed in claim 1, wherein the pair of runners (314, 316) extends towards each other to be connected to the contact wire at one end using connecting clamps (318) and extends away from each other at the other end to provide running surface for the locomotive pantograph.
8. The neutral section assembly (300) as claimed in claim 4, wherein the pair of runners (314, 316) is secured by connecting it with the first connecting block (320) of each composite insulator to provide stability to the neutral section assembly (300).
9. The neutral section assembly (300) as claimed in claim 4, wherein the neutral section assembly (300) is held by an overhead catenary wire (202) using a supporting assembly (206) connected to the first connecting block (320) , wherein the supporting assembly (206) comprises a turnbuckle

(210) and a guy wire (212) connected end to end to support the neutral section assembly (300).
10. The neutral section assembly (300) as claimed in claim 1, wherein
the composite insulator is of a material comprising one of a non-metallic core, and a silicon rubber housing.