STANDARDS FOR FIBRE OPTIC TRANSMISSION SYSTEM C3-3 OPGW for... · STANDARDS FOR FIBRE OPTIC TRANSMISSION SYSTEM ... OPGW Install Date Jan 2016 ... and wire fittings such as grounding

STANDARDS FOR FIBRE OPTIC TRANSMISSION SYSTEM

PART C3.3: ERECTION AND INSTALLATION OF OVERHEAD FIBRE OPTIC LINKS

Rev 0 January 2016

OPTICAL GROUND WIRE STANDARDS

FIBRE OPTIC TRANSMISSION SYSTEM PART 1b: ERECTION AND INSTALLATION OF OVERHEAD

FIBRE OPTIC LINKS

Document Technical Specification- OPGW Install

Date Jan 2016

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COMPILED BY:

Name

ACCEPTANCE BY EMPLOYER:

Name Functional Responsibility Date

REVISION CONTROL:

Revision No.

Notes Date



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1.0 GENERAL INFORMATION

1.1 Scope

1.1. This document outlines basic installation methods of OPGW for existing and newly constructed transmission lines. The installer

should be thoroughly familiar with the installation of conventional overhead ground wire and conductors. Additional information

can be obtained from the SANS10280 Overhead Power Lines for Conditions Prevailing in South Africa.

1.2. Optical Ground Wire (OPGW) was developed to provide a large capacity telecommunications system utilizing overhead power

transmission lines. Serving the additional purpose of an overhead ground wire, the OPGW is constructed of aluminium clad

steel strands and aluminium alloy strands stranded with stainless steel tubes or surrounding a fibre unit (core) which contains

optical fibres. OPGW can be installed using the basic stringing methods currently employed for overhead ground wires, with

minor variations.

2. NORMATIVE REFFERENCES

CIGRE TF 22.11.03 Guide to fittings for optical cables on transmission lines – Part 1: Selection and use.

IEC/TR 61328:2003 Live working – Guidelines for the installation of transmission line conductors and earth wires – Stringing equipment and accessory items.

SANS 60793-1-40/IEC 60793-1-40:2001 (SABS IEC 60793-1-40) Optical fibres – Part 1-40: Measurement methods and test

procedures – Attenuation.

SANS 61230/IEC 61230:1993 Live working – Portable equipment for earthing or earthing and short-circuiting. NRS 061-2:2004: SPECIFICATION FOR OVERHEAD GROUND WIRE WITH OPTICAL FIBRE Part 2: Instal-

lation Guidelines, Edition 1

NRS 088-2 Duct and direct-buried underground fibre-optic cable Part 2: Installation guidelines

3. PREPERATION PROCEDURES

3.1. Survey of the line

Prior planning for installation of the OPGW conductor is performed by surveying the line, taking into account the following parameters:

a) Length of each drum

The OPGW drum lengths are determined based on the following considerations:

i) position of the tension towers, tower access,

ii) distance between supports and crossing with other lines,

iii) roads, railways routes, services and other obstacles.

b) Splices

The position of the splices depends on the maximum available length of OPGW, on the position of the towers and the tower access. The splice locations of the OPGW conductor must be planned to allow for splicing of the optical fibres. The drum lengths will be engineered to locate the conductor splices at predetermined towers on each end of a stringing section.



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3.2. Transport, loading, offloading

a) OPGW conductor drums should always be transported and handled in an upright position. Never lay a drum of conductor

on its side.

b) The drums must be offloaded, or moved in a controlled manner such that the drum remains in vertical position and the

sides of the drum are not damaged by the offloading process.

c) Under no circumstances should the drum be rolled off the delivery or transport vehicle.

d) The drums can be moved by rolling a short distance ensuring that there are no objects that may damage the staves. The

direction of rotation should follow the instruction mark on the drum.

e) After the transport and offloading, the drums must be inspected to verify that they have not been damaged and that none

of the staves or safeguards are broken.

f) Each drum of OPGW must be tested prior to and after installation to ensure that fibre damage has not occurred during

shipping and/or stringing operations using an OTDR tester on each fibre.

g) The ends of the OPGW must be sealed to prevent water ingress.

h) All conductor protective packaging (wood lagging or flex wrap) must remain in place on all drums until placed on pay-out

racks and rack is positioned for conductor stringing.

i) The conductor drums should be transported with the inner tail securely connected to the outside of the drum flange. This

connection should be loosened, but not removed, prior to stringing.

3.3. OPGW Conductor Installation preparation

a) Care must be taken to avoid damaging the OPGW during handling and stringing operations. Avoid sharp bends to the

conductor and take precautions to prevent crushing the OPGW during placement. The transmission quality of the optical

fibres can potentially be degraded if the OPGW is subjected to excessive pulling tensions or excessively small bend

diameters.

b) Always observe the recommended values for Maximum Stringing Tensions and Minimum Bend Radius. More information

about these values can be obtained from manufactures data sheets.

c) This allows the inner layers of conductor to adjust themselves to the varying tensions seen during installation. As the

conductor makes these adjustments, the inner tail may extend requiring periodic attention.

d) Controlled tension stringing method of installation is required.

e) Ordinary stringing equipment can be utilized as if installing standard overhead ground wire.

f) Suitable equipment includes pullers, tensioners, drum winders, and stringing blocks. Figure 1 illustrates a typical stringing

setup.



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FIGURE 1a - Typical Stringing Setup

g) The tensioner as well as the puller should be placed aligned with the conductors. The maximum acceptable deviation

angle α is 30º.

FIGURE 1b - Typical Stringing Setup- Maximum Deviation Angle α

h) After installing dead ends, the free end of the OPGW is secured down the towers to the ground for splicing.

i) The length of the free conductor should be at least the tower height, plus an additional 20 meters to accommodate

splicing. After stringing, this excess conductor must be coiled and temporarily stored above the anti climb barrier on the

tower until splicing occurs.

j) The OPGW attachment hardware, including dead ends, suspension clamps, and wire fittings such as grounding clamps

must be designed to provide the necessary holding strengths and prevent deformation of the fibre unit which could

potentially damage the optical fibres.

4. STRINGING PROCEDURES

4.1. Stranded wire pulling lines are generally used, although nylon ropes can also be employed. In either case, the line must be rated

to withstand the required stringing tensions. The pulling line should have the same lay direction as the OPGW to help resist the

tendency to rotate under stringing load.

4.2. If an existing overhead ground wire is to be removed, this may be used as a pulling line for the OPGW. A visual inspection must

be made of the existing ground wire to be sure it is in suitable condition for use as a pulling line. If there is any concern about

the ability of the existing overhead ground wire to withstand the stringing tensions, it should be pulled out and replaced with a

pulling line.



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4.3. A bull-wheel type tensioner with round (not “V” type) polyurethane lined contact grooves must be used unless otherwise approved

by the Engineer (See Figure 2). The tensioner should have two bull wheels, each with multiple grooves to minimize conductor

damage. The tensioner should be capable of maintaining the required tensions at various pulling speeds. Positive braking

systems are necessary for pullers and tensioners to maintain the tension when hauling is stopped. Minimum diameter of the bull

wheels should not be less that 70 x D (diameter of the OPGW).

Figure 2 Typical Tensioner

4.4. The OPGW must be reeved (threaded) through the bull wheel tensioner properly. Left hand lay OPGW (typical USA) is reeved

from right to left. Right hand lay OPGW (typical International), is reeved from left to right. A thorough explanation of the reeving

process can be found in IEEE Std 524-2003. This arrangement is necessary to avoid any tendency to loosen the outer layer of

strands and to avoid induced torque during installation.

4.5. The tensioner must be equipped with a dynamometer.

4.6. The drum shall be placed directly in line with the tensioner. The distance from the drum to the tensioner should be at least 7.5

meters. The OPGW shall not be permitted to scrape the drum flanges while being played out.

4.7. The OPGW conductor drums are not designed to withstand the braking forces present during stringing. Direct tensioning of the

OPGW from the conductor drum is not acceptable. Back tension on the drum should only be enough to keep the conductor

properly seated in the tensioner grooves and to prevent overshooting and bird caging.

4.8. Two basic types of pulling machines are recommended for tension stringing (See Figure 3). These are either drum type or bull

wheel type pullers. Positive braking systems are required in either case. On a drum type puller, the pulling line is taken up

directly onto the drum. On the bull wheel type, the line is threaded onto two bull wheels, much like the tensioner, and onto a

self-winding drum.

Figure 3. Typical Pulling Machine



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4.9. The puller must also be equipped with a dynamometer with automatic disconnection in case of over tension on the OPGW.

4.10. Stringing blocks, sometimes called travellers, must be mounted on the structure at the OPGW attaching point in the normal

manner.

4.11. The stringing blocks should have neoprene lined grooves. The linings should be in good condition and adhering to the block.

Minor rough areas can be sanded out to ensure the lining is smooth.

4.12. Uplift rollers (which attach to the installation sheave wheel) or hold-down blocks (which are separate blocks) need to be placed

where uplift of the pulling line is likely to occur (due to its higher tension/weight ratio than the conductor). This will typically occur

going up inclines or at a low point in a section. These devices must also have a break away feature in the event of fouling or

incorrect installation.

4.13. The Tensioner and Puller should be positioned for a 3:1 ratio to the stringing block on the first structure adjacent to the equipment.

See Figure 1. The tensioner should be placed in line with the first two structures (or first span) of the pull. Likewise, the puller

should be placed in line with the last two structures (or last span) of the pull. This minimises the deviation angle seen by the

conductor during the installation process.

4.14. This minimum stringing block diameter and distance to the tensioner (3:1) will help prevent deformation of the fibre unit (alumin-

ium pipe, stainless tell tube or slotted core), which protects the optical fibres in the OPGW.

4.15. The use of an Anti-Rotational Device (ARD) (See Figure 4) depends largely upon the construction of the optical ground wire.

This a device is used to prevent the OPGW from twisting while being pulled. Variations of these devices have been successfully

used. For conductors with helically stranded stainless steel tubes or designs with two layers of wires, an anti-rotational device

may or may not be required. Confirmation whether one is needed for your particular application must be obtained from the

conductor manufacturer.

4.16. If confirmation cannot be obtained, the conservative approach must be used and the installation must be done with the use of

an anti-rotational device. For conductors constructed with an unstranded stainless steel tube in the centre of the conductor or

single layer conductors, an anti-rotational device is always a requirement.

4.17. If the anti-rotational device is not preventing the conductor rotation or if the anti-rotational device is wrapping around the OPGW,

a stiffer or heavier device is required. The weight and length of the ARD will depend upon the construction of the optical ground

wire.

4.18. The anti-rotational device attaches to the OPGW with a Kellum type grip. The grip must be appropriately sized for the OPGW

diameter and pulling tensions.

Figure 4: OPGW with Anti-Rotational Device

5.19 The weight of the anti-twisting devices must be high enough to prevent OPGW conductor rotation. The minimum values recom-

mended for each counterweight are as follows:



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- Spans 300 m and below- 12 kg

- Spans 300 m -700 m- 15 kg

- Spans above 700 m - 20 kg

For Installation lengths of longer than 4000 metres these values should be increased by 5 kg.

5.20 After the counterweights have been installed, they should not be removed until the conductor is secure and cannot rotate.

5.21 The OPGW must be kept under constant tension during the stringing process to keep the line clear of both the ground and other

obstacles that could cause damage to the conductor.

5.22 Do not cut the OPGW with ratchet cutters, or other types of tools that could crush the fibre unit. The use of a hacksaw will ensure

the fibre optic units are free to move within the pipe.

5.23 During stringing, the first few feet of OPGW may elongate, and this will prevent unnecessary strain on the optical fibres.

5.24 It is important to monitor the tensions and ensure that excessive tension is not applied as the OPGW passes from the drum to

the tensioner.

5.25 The following requirements are minimum requirements for this specification:

Item Requirements

Minimum Bull Wheel Diameter: 70 x D (D=OPGW diameter) For larger diameter OPGW conductors

where 70 x OD exceeds 1.5m, a 1.5m bull wheel must be used.

Recommended Block Diameter 40 x D

Minimum Conductor Bend Radius During

Installation:

20 x D (Dynamic);

After Installation (Static):15 x D

Maximum Stringing Tension 20% OPGW’s Rated Breaking Strength(note 2)

Pulling Speed 40 meters per minute or 2.4 km per hour

Minimum distance from puller and tensioner

to the stringing block:

3:1 Ratio

Total number of spans in each stringing sec-

tion:

Typically 20 to 30(note 1)

NOTES:

1The maximum number of spans is included as a reference only; since this will vary considerably due to differences in terrain, span lengths, line angles, etc.

2The stringing tension is always measured at the tensioner side. The maximum stringing tension must be a half of the maximum sagging tension and never exceed 20% of Rated Breaking Strength of the OPGW.



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6. SAGING METHODS

The methods and procedures for sagging the OPGW are the same as those for normal overhead ground wires. For determining sags, the installer must use the sag-tension design information provided by the design Engineer.

6.1 A temporary grip is installed on the OPGW for tensioning. The grip must be designed to hold the OPGW without damage, and

in particular not pinch the conductor or crush the aluminium pipe. The installer provides a comealong, sometimes referred to as

a pocketbook grip (see Figure 6), that can be attached anywhere along the length of an OPGW. Figure 5 illustrates unsatisfac-

tory comealong designs.

Figure 5 (a) Chicago grip Figure 5 (b) Kito Grip

6.2 Some types of gripping devices that might damage the OPGW such as Chicago grip or Kito grip are strictly prohibited for use

on OPGW. Certain types of pre-formed guy grips can also be used successfully, but their use in stringing applications must be

approved by the Engineer.

Figure 6 Comealong (Pocketbook Grip)



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7 DEADENDING AND CLIPPING IN HARDWARE

7.1 Deadends are installed on OPGW spans that terminate at splicing towers or ends of the system. Deadends are also used at

angle structures when the angles are too great to use suspension clamps. Suspension clamps are normally used at the remaining

towers. These types of hardware (dead end and single suspension) are illustrated in Figures 7.

Figure 7 (a) OPGW Deadend-(Bolted Type) Figure 7 (b) OPGW Suspension Clamp-(Cradle Type)

7.2 Tower bonding clamps and tower guide clamps are illustrated in Figure 8 below.

Figure 8(a) Tower Bonding Clamp Figure 8(b) Tower Guide Clamp

7.3 Vibration Dampers are installed for specific span lengths to prevent damage caused by Aeolian vibration. Various types are

shown in Figure 9

Figure 9(a) Stockbridge Vibration Damper Figure 9(b) Spiral Vibration Damper



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7.4 General rules for hardware are as follows:

a) Single Suspension, to be used at structures with line angles between 0 and 30 degrees.

b) Double Suspension, to be used at structures with line angles between 30 and 60 degrees.

c) Dead End, to be used at structures with line angles over 60 degrees.

d) Sometimes, when double suspensions are not desired, the dead ends can be used starting from line angles

of 30 degrees, instead of 60 degrees.

e) OPGW is installed using stringing blocks. If left in the stringing blocks for extended periods of time, the potential for

motion induced damage (Aeolian vibration) increases. Also, the creep of the conductor is affected due to the change in

the initial condition on the conductor. In order to diminish the probability of motion induced damages and creep rate

change, it is recommended that tensioning and anchoring of the OPGW to the structure and removal of the stringing

blocks be completed no later than 48 hours after stringing of the conductor.

f) There are several ways to lift the OPGW from the stringing blocks in order to install the hardware. Basically,

comealongs are attached on both sides of the block and a coffin hoist is placed over the tower arm. The hooks of the

coffin hoist are attached to the comealongs and jacked up to form a small loop in the OPGW. The block can then be

removed and the armour rods can be placed on the OPGW then attached to the structure. Alternately, certain types of

preformed wire grips can be used instead of comealongs.

g) If vibration dampers are required for this span, these should be placed on the OPGW immediately after clipping

in. Dampers may not be required at every structure; their locations will be specified by the Engineer. Drawings of a

typical Stockbridge and Spiral damper are shown in Figure 9.

8 SPLICE POINTS

8.1 Splice points will be located at the beginning and end of each OPGW drum. After completion of sagging and clipping, the surplus

OPGW should be coiled and attached temporarily to the tower. Coils should be approximately 1 to 1.5 meters in diameter. The

coils should be fixed on the tower to prevent any damage to the OPGW prior to splicing.

8.2 The exposed ends of the OPGW should be re-sealed to prevent moisture from entering the fibre units. The conductor drum may

be supplied with a pair of plastic caps for sealing the conductor ends. Electrical tape, RTV silicone, or other means can also be

used for this purpose.

8.3 The OPGW will be trained down the tower and to the ground for splicing. Do not cut off any excess length of the OPGW at this

time. To facilitate splicing, the OPGW should extend a minimum of 23 meters beyond the bottom of the tower. The length of

OPGW running down the tower should be attached to the structure using appropriate guide clamps, spaced every 1.8 to 2.4

meters of running length. Several types of guide clamps are illustrated in Figure 8.

8.4 The splice enclosure will typically be installed on the structure between 4.5 to 6 meters above the ground. In most cases, it will

be desirable to store extra conductor on the tower. This will allow the splice box to be removed and lowered to the ground if it is

ever necessary. This can be accomplished with a simple loop of OPGW below the splice box or by permanently storing a coil of

OPGW higher on the tower.

8.5 The additional slack is to be coiled and secured using the approved cleats to a location above the Anti-climbing gear (ACG) on

the OPGW side of the joint prior to splicing. On the underground cable side an additional 5 metres of slack beyond the position

of the splice should be coiled and buried at the joint position.



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9 ANCHORING THE OPTICAL UNITS IN THE SPLICE BOX

The following is an example of anchoring the optical units when installing Loose Tube OPGW (Aluminium pipe designs) in a Dome type Splice Box (See Figure 10).

9.1 Place a piece of electrical tape on the individual optical units, 36 to 46 cm from the entry bushing of the slice box.

9.2 Working with one optical unit at a time, cut the binder tape at this mark, on the entry bushing side.

9.3 Unwrap the binder tape back to the entry bushing and cut the BINDER TAPE ONLY.

9.4 Cut the yarn at the electrical tape and use the yarn to anchor the optical unit by threading the yarn through the eye-bolt and tying

in a series of half-hitches. Make sure that the yarn is tied off in line and to the eye bolt in the proper position from where the

individual OPGW conductors enter the splice box.

9.5 Repeat the previous steps for the remaining OPGW conductor(s).

9.6 Tape the optical units together after they have been secured to the eye-bolts. Tape the units (duct tape is recommended) to the

top outside radius of the box. This will help support the units and prevent damage of the units at the bushing.

9.7 Tighten the retaining nut so that the bushing is sealed around the pipe.

9.8 Tape the optical units together every 0.6 meters.

9.9 Stop taping the optical units 1.8 meters from the free end.

9.10 Tape each individual optical unit (s) up to 1.45 metres from the free end.

9.11 Remove the yarn and the binder tape from the optical unit(s) along the 1.45 metre section towards the free end.

9.12 A similar procedure is recommended for Loose Tube OPGW and Tight Structure OPGW in an Splice Box

Important Note: The manufacturer of the splice box must supply instructions for installing the Loose Tube OPGW and Tight Structure OPGW in their splice box. No matter the type of splice box used, the aramid yarn must be tied off inside the box, to an eye bolt or other element, to prevent a pull-back tension on the conductor core.

Figure 10 Typical Dome Type Splice Enclosure

1. Dome Cover 2. Dome retention strap 3. Base and OGGW Clamps 5. S Bracket 6. OPGW Conductor



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10 OPGW TO UNDERGROUND CABLE JOINTS.

The above shall be in accordance with section 4.3.4 and 4.3.7 of Appendix 1.

10.1 The approved stainless steel splice enclosure (SSSE) must be mounted onto the top of a vertically installed 2m high, 50mm

diameter stainless steel pipe buried 0,8m into the ground. The stainless steel pipe must be secured to the inside of the tower leg/ just off the gantry leg using an approved stainless steel bracket.

10.2 The DN50 Kabelflex tubing for the underground fibre cable must be inserted into the base of the stainless steel pipe. The top of

the pipe must be sealed with self-expanding polystyrene type foam, (‘Sista’ foam), to prevent ingress of water. Joints with the DN50 Kabelflex tubing must be taped with self-amalgamating rubber tape to prevent the ingress of moisture and sand.

11 TERMINATIONS INTO FIBRE COMMUNICATION PANEL (FCP)

11.1 Approximately 3m of slack of the unarmoured heavy duty underground duct cable within the DN50 Kabelflex tubing must be

retained at the end away from the tower, where an underground cable runs into the Fibre Communication Panel (FCP) of a

substation. This is in preparation for the termination of the underground cable into the patch tray of the FCP.

11.2 The DN50 Kabelflex tubing must be correctly glanded and terminated to the gland plate at the base of the FCP.

11.3 At least 2m of slack fibre cable must be provided at the base of the FCP, for future maintenance purposes.

11.4 An approved fibre patch drawer, equipped with ‘pigtails’ with FC/PC mid-couplers shall be used.

11.5 The fibre transmission link/ cable cores shall terminated at the FCP by splicing onto the pigtails within the patching drawer.

11.6 The cable into the patch tray/ drawer must be tagged or labelled to display the substation name of the remote end of the link.

11.7 The front of the patch tray must be labelled with the name of the source, or source substation of the fibre link. The core number

of the connectors shall also be displayed on the front of the patch drawer. This label must be black lettering on a white back-

ground.

11.8 The above shall be in accordance with section 4.3.6 of Appendix 1.

12 STRINGING AND HANDLING OPGW DIAMETERS AND BENDING RADIUS

Refer to OPGW typical Stringing Setup drawing

12.1 Maximum OPGW recommended stringing tension is 20% (at tensioner) of the rated breaking strength

12.2 The minimum bull wheel diameter for tensioners is 70 x D. (Where D represents the nominal diameter of the OPGW).

For larger diameter OPGW conductors where 70 x OD exceeds 1.5m, a ~1.5m bull wheel may be used.

12.3 The recommended stringing sheave (root) diameter is 40 x D. (Where D represents the nominal diameter of the OPGW).

This is based on a sheave through angle of 45° and maximum stringing tension (at tensioner) of 20% of the rated strength

of the OPGW.

12.4 The minimum bending radius after installation (static) for the OPGW is 15 x D. (Where D represents the nominal diameter

of the OPGW).

12.5 The minimum bending radius during installation (dynamic) for OPGW is 20 x D. (Where D represents the nominal diam-

eter of the OPGW).

NOTE: Based on actual OPGW size, etc., care must be taken when bending the OPGW to avoid kinking the strands and,



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therefore, damaging the optical fibres contained within the central pipe.

12.6 The minimum permanent bending radius for the OPGW is 15 x d. (Where “d” represents the diameter of the aluminium

pipe or the slotted core).

12.7 The minimum permanent bending radius for the stainless steel tube is 45 x d. (Where “d” represents the diameter of the

stainless steel tube).

12.8 The minimum permanent bending radius for plastic buffer tubes is 8 cm.

12.9 The minimum permanent bending radius for the optical fibres is 3.8 cm.

12.10 The swinging angle of the stringing block shall be controlled corresponding to the swinging angle of the OPGW stringing

plane to help prevent the conductor from riding out of the traveller or excessive twisting during installation. The conductor

should be travel thought the lowest part of the groove.

12.11 The following are minimum diameters of stringing blocks at:

a) Terminal Structures

The minimum stringing (sheave) block diameter (root) of 40 x D (where “D” represents the diameter of the OPGW) is considered satisfactory if the pulling line slope is at least three horizontal to one vertical from the traveller to the site and the stringing tension does not exceed 20% of the OPGW’s rated breaking strength.

b) Suspension and Angle Structures

i) For Suspension structures (line angle=0°) and stringing angles of 20° or less, a minimum sheave root

diameter of 30 x D is acceptable.

ii) For stringing angles between 20° and 45°, a minimum sheave root diameter of 40 x D is required.

iii) For stringing angles between 45° and 60°, a minimum sheave root diameter of 50 x D is required.

iv) For stringing angles greater than 60°, a minimum sheave root diameter of 60 x D is required.

11. STRINGING HARDWARE

11.1. Comealongs for Optical Ground Wire (OPGW)

a) General

OPGW Comealongs are stringing tools designed for pulling optical ground wire up to initial sag tensions. If the required tension is greater than the rated tension of a single comealong, two or more comealongs should be used (refer to Instal-lation Instructions). When desired sag tension is reached, the conductor should be dead ended promptly and the comealong removed.



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b) Maintenance

Comealongs must receive periodic maintenance. This practice should consist of a thorough cleaning with close inspec-tion for nicked or rough conductor grooves, cracked body, bent eye bolts, or damaged bail. The eyebolts should be kept clean and oiled. The conductor groove should be kept clean and dry. After each six months use and at the beginning of each job, all comealongs should be subjected to a pull test equal to its rated strength. If any damage is found, the comealong should be disposed of or sent to the factory for rework and recertification.

c) New Comealongs

i) Loosen bolts so that the comealong may be opened sufficiently. Check for cleanliness of bore and permit conductor

entry into the conductor groove.

ii) Position the come along a minimum of 10 feet from the dead end or joint being installed. This will assist in reducing

the potential for bird caging of the conductor during compression.

iii) Place the conductor into the conductor groove of the comealong, then close the comealong and finger tighten the

bolts.

iv) Using a torque wrench, tighten bolts in sequence from bail end to nose of the comealong (see diagram below). It

will take a minimum of 6 passes to achieve the correct torque on each bolt. On the first pass, tighten the bolts to

80% of the target torque, ensuring proper clamping force is achieved.

d) Inspection of Used Comealongs

i) Before each job, thoroughly clean the comealong and closely inspect for nicked or rough conductor grooves,

cracked body, bent eye bolts, or damaged bail.

ii) If any damage is found, the comealong should be disposed of.

iii) After cleaning, each comealong should be subjected to a pull test equal to the rated strength stamped on the

comealong.

Figure 11. Typical Comealong

e) LOAD RATING:

Maximum tension limit is 50% of the rated strength of the OPGW or 2500 kg, whichever value is smaller.

f) WARNING:

Comealongs are not intended for use as dead ends and are not recommended to hold conductors at sag tension limits for longer than 6 hours.



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g) Using Comealongs in Tandem

If the installation tension is greater than the rated strength of one comealong, then comealongs must be used in tandem. The comealong bails should be bridled with a sling (consisting of shackles and wire rope) and pulley block to insure equal distribution of the load. To prevent damage to the conductor by the shackles, place protective sleeves over the conductor (Figure 12).

The rated strength of this tandem configuration is 150% of the lowest rated comealong. For example, if one comealong is rated for 4000kgs and the other rated for 5000kgs, then these two comealongs in tandem will have a rated strength of 6000kgs (150% of 4000kgs).

Figure 12. Typical Comealong tandem arrangement

11.2. Stringing Block

Figure 12. Typical Stringing Block

The minimum stringing sheave (root) diameter is 40 x D. (Where D represents the nominal diameter of the OPGW). This is based on a sheave through angle of 45° and maximum stringing tension (at tensioner) of 20% of the rated strength of the OPGW.

12 TESTING

12.1 Before cable installation

Prior to cable installation, each optical fibre is verified using OTDR for each drum delivered.



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12.2 Measurements after installation

After the cable has been installed, and prior to the splices, each of the cable fibres is verified once again using OTDR. These new values are compared with those obtained in 12.1. in order to ensure the absence of any problems.

12.3 After Splices measurement

After splicing, each joint is optically verified using OTDR in order to ensure that the attenuation values are within the required margins.

13 FINAL ACCEPTANCE TEST AND HANDOVER OF FIBRE LINKS

13.1 After installation, a final measurement of the transmission characteristics is taken and the values are duly recorded. A copy of this is submitted to the Engineer.

13.2 Handover of Completion Form

Handover occurs once the contractor/ installer of a link has completed the installation of the fibre link from termination point to termination point. Installation of the fibre link includes installation of the fibre carrier, completion of all splices and full testing and proving of the fibre link. The termination point is the patch panel within the Fibre Communication Panel (FCP). Various tests are done before handover. These tests shall be in accordance with 5.3 of Appendix 1.

The contractor is to ensure that Completion Form for Overhead Optical Fibre Links in Appendix 2 has been completed correctly and handed over to the Project Engineer of Msunduzi Electricity. This includes the submission to the Engineer of ‘as-built’ diagrams of the route, showing all towers where joints are positioned, and distances between joints and terminations. It also confirms that the fibre link has been tested and proved to standard, and that the results have been submitted to the Engineer.

14 ENVIRONMENTAL

14.1 Withdrawal of special waste (toxic and dangerous)

If any type of special waste such as oil, grease, solvents, saturated gloves or rags, etc. are produced during cable installation, following procedure must be followed:

· Materials must be placed in heavy-duty cardboard containers or steel drums, indicating what type of waste it is. · Contact Environment Department. This department will furnish the data for the administrator in charge

of such waste. · Such waste must not be abandoned, mixed with other waste, or sent to the ,landfill dump

14.2 Withdrawal of non-toxic or inert waste

· Excess materials or waste such as aluminium, optic fibre, plastic, wood, iron, etc., must be sent to an authorized recycler or a controlled landfill site. Regardless of the amount, the waste must never be abandoned on site.



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APPENDIX 1: APPENDIX 2: COMPLETION FORM FOR OVERHEAD OPTICAL FIBRE LINKS

Preamble

This checklist is to completed and signed in sequence by the Contractor/ Consultant or installer, as the work for aspects of the fibre transmission link are completed. The same sheet is to be used for aerial and underground systems.

LINK DESCRIPTION: Contract No./ Order No.: ...................................................................................................

End A End B

Length of route No. Of Tubes

No. Of Joint Boxes

Make & Model of Splicer used Make & model of OTDR used

Item Description Date Signature Remarks

1. OPGW: Considerations during Stringing of the Conductor at Towers where Splice Enclosures are to be erected :

a. The positions of mid-link joints/ splices are at accessible towers, and are not insulated or strain assemblies.

b. The OPGW runs on the inside of the tower/ gantry leg.

c. The OPGW is strung with at least 5m of slack available at ground level at splice positions

d. The OPGW has been cleated at 2m intervals with bi-metallic clamps/ cleats, down to the ACG.

e. No slack in OPGW exists between cleats.

f. No potential exists for abrasions to occur against tower/ gantry metal.

g. There is no unnecessary bird caging; where unavoidable, birdcage has been form wrapped.

h. The 5m of spare OPGW is coiled and securely mounted out of reach, prior to splicing. In the case of a gantry, the coil is mounted within the top quarter and diagonally within the leg; in the case of a tower, the coil is secured above the ACG

i. An as-built diagram of the route, showing all towers where joints are positioned, and distances between joints and terminations has been submitted to the Engineer.

2. Installation of NEX tubing between Gantry/ Tower and FCP position in Control Room:



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a. Approx 2-3m of NEX tubing slack was retained at Tower/ gantry position for insertion through the vertical stainless tube to which the approved stainless steel splice enclosure is to be attached.

b. Approx 3-4m of NEX tubing slack was left coiled beneath the FCP panel

3. Splicing enclosures:

a. The OPGW is adequately bonded to earth within 2m of the final position of the approved stainless steel splice enclosure.

b. An approved stainless steel splice enclosure was used, according to supplier specification.

c. Sufficient slack has been retained, to enable work to be done at ground level.

d. The correct clamping ferrule, together with correct half shells was used at the base of the joint where the OPGW is clamped into the splice enclosure.

e. An approved fusion splicer was used.

f. The Standard Fibre Numbering system was adopted during splicing.

g. The OPGW has sufficient bending radius into the dome joint.

4. Splices between sections of OPGW:

a. The coil and splice enclosure is secured above the ACG.

b. The correct stainless steel bracket, (straight or right angled), was used to attach splice enclosure to the leg of tower/ gantry.

5. Splices between sections of OPGW and Underground cable:

a. The Stainless Steel tube was planted 800mm deep into the ground at the foot of the tower/ gantry over the NEX tubing from the FCP panel.

b. Approx 5m of underground fibre cable was buried at the base of the joint position.

c. ‘Sista’ expanding foam was used to seal the top of the stainless steel tube, beneath splice enclosure.

d. In the case of a gantry, the coil plus splice enclosure is mounted within the top quarter and diagonally within the leg; in the case of a tower, the coil and splice enclosure is secured above the ACG.

6. Jointing of fibre cables within the FCP in the Control Room NOTE: FCP will have been equipped by DME with a splicing tray, fitted with mid-couplers, compression glands and pigtails for each fibre

a. NEX tubing is secured to the gland plate at the base of the FCP with a 50mm male adaptor, (provided by DME).



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b. All fibres are spliced onto pigtails, and fibres on splicing tray neatly made off

c. Standard Fibre Numbering system adopted

d. The cable into the patch tray/ drawer is tagged or labelled to display the substation name of the remote end of the link.

e. The front of the patch tray/ drawer has been correctly labelled, showing the core numbers, and source of the cable.

7. Final Testing of Links and splices

a. Red Light Test (End to End test) of fibres between FCP and FCPs of adjacent substations witnessed. (ie Fibre 1 at FCP connected to Fibre 1 at FCP of next substation, etc)

b. OTDR test of all fibres between FCP and FCP of next substation(s) (in forward and reverse directions) have been performed and it has been proved that attenuation levels are within permitted limits, at 1310 & 1550nm.

c. Fibre parameters for OTDR testing: i. Helix Factor ii. Index of Refraction iii. Rayleigh Backscatter Factor

d. Electronic & hardware copies of the OTDR and attenuation reports have been submitted to the Engineer.

Documents

STANDARDS FOR FIBRE OPTIC TRANSMISSION SYSTEM C3-3 OPGW for... · STANDARDS FOR FIBRE OPTIC TRANSMISSION SYSTEM ... OPGW Install Date Jan 2016 ... and wire fittings such as grounding