Why are insulated overlaps installed?

Why are insulated overlaps installed?

Insulated overlaps are installed chiefly for providing isolating facilities required for the operation and maintenance of OHE. In case two lengths of OHE belong to two adjacent elementary sections, there will be insulated overlap span.

What is the use of isolator in overhead equipment?

The isolator allows the current to the section to be interrupted for maintenance. On overhead wires designed for trolley poles, this is done by having a neutral section between the wires, requiring an insulator.

What is the separation gap length of the two sets of conductors insulated overlaps?

In insulated overlaps the two sets of conductors are separated by 500 mm in air. Bectrical continuity is provided by an isolator, interruptor or booster transformer.

What is overhead equipment in electric traction?

Overhead Equipment means the electrical conductors over the tracks together with their associated fittings, insulators and other attachments, by means of which they are suspended and registered in position for the purpose of electric traction; Sample 1.

What is insulated overlap?

Insulated Overlaps In Insulated Overlaps, the two sets of Conductors are separated by 500 mm in air. The gap is decided requiring the minimum air clearance for 25 kV. With this clearance, it is possible to make one length dead keeping the other energized by opening the switch that normally connects the two lines.

What insulator is used in traction?

Polymeric based Composite insulators are extensively used for overhead rail electric traction system; these insulators play an important role in the traction electrification which supply power to the locomotives of train.

What is a section insulator?

The section insulator (SI) is a device installed in the catenary system for electrical separation of two electrical feeds while allowing for the passage of a vehicle pantograph, such as in a crossover between two adjacent tracks.

What is stagger railway?

Stagger :- The horizontal distance between track center and contact wire, measured on contact plane is called as stagger.

What is stagger in Ohe?

Stagger :- The horizontal distance between track center and contact wire, measured on contact plane is called as stagger. Its normal cum maximum value is Straight Track – ± 200 mm.

What is SP and SSP in railway?

Sectioning and-Paralleling Post (SP) 10207. Sub-Sectioning and Paralleling Post (SSP)

Which insulator is used in railway?

The material of rail insulator is usually Reinforced Nylon 66 (PA66), with the color white, dark brown or black.

What are staggered joints?

The staggering of rail joints is logical because it avoids placing two weak spots, the joints directly opposite each other; it reduces the impact at the joints to that of a wheel load instead of an axle-load; and it produces a more uniform vertical continuity of the track.

What is meant by un-insulated overlap in electrical wiring?

It is called un-insulated overlap when connected firmly and insulated when connected through a switch like isolator or interrupter. The need for the overlaps arises because of Restriction on the length of the conductor due to handling of weight, drum size, tension to restrict the sag and elongation due to temperature variation depends on length.

How do insulated overlaps work?

In Insulated Overlaps, the two sets of Conductors are separated by 500 mm in air. The gap is decided requiring the minimum air clearance for 25 kV. With this clearance, it is possible to make one length dead keeping the other energized by opening the switch that normally connects the two lines. The switch is either an isolator or interrupter.

Is it possible to overlap overhead contact and catenary wire?

This is not possible in case of overhead contact and catenary wire. Similar purpose in OHE is achieved through overlaps. Overlap is defined as an arrangement where two set of contact wire runs together in parallel for a short distance without any mechanical or electrical connectivity but facilitating smooth movement of pantograph over it.

What is the need of overlaps in a conductor?

The need for the overlaps arises because of Restriction on the length of the conductor due to handling of weight, drum size, tension to restrict the sag and elongation due to temperature variation depends on length. Maintenance management of higher length is difficult for schedule replacement, kink attention etc.