METHOD OF STRINGING CONDUCTORS & OPGW

·           GENERAL PURPOSE

Purpose of this stringing work method is to guide all the crews / workers who will be involved in stringing earth wire, optic cable, conductor and in installation of fittings, so that the works can be done properly with good quality and safely. Therefore before the work start for every sequence, the crews must ensure about their duties agenda, target of work, safety tools and the conditions of equipments and machineries to be used.

·           SCOPE OF WORK

The scope of stringing work generally can be described as follow :

1.       Preparation to works :

·         Supporting documents [ drawings / Earthing measurement / Final Report of Tower Erection / other approval ].

·          Line route [ Bush clearing / Other utilities / determination drum place, winch place / access road etc ].

·         Material to be installed [ OPGW / Conductors / Earth wires / lnsulators /Fittings / Accessories ].

·          Equipments and Tools [ Tensioner / Puller / Counter weight / Crane /Truck / drum stand / theodolite, etc ].

·         Safety Tools [ Equipments and Workers ].

2.       Installation works.

3.       Installation running block.

4.       Anchoring.

5.       Pulling pilot wire.

6.       Pulling earth wire conductor.

7.       Termination pulling.

8.       Sagging.

9.       Fitting & clamping.

10.   Accessories & Damper.

11.   Recording

·           WORKING STAGES

1.       PREPARATION.

·           Supporting Document.

Before starting to determine range of stringing, some major documents should be provided and approved. The relative documents are as follows:

Ø  Final Check of Tower Erection of all towers of the stringing section.

Ø  Earthing Measurement records for the respective towers.

Ø  Bush Clearing in the respective stringing section.

Ø  Approval for carrying out the stringing in respective section.

·           Line Route

Clearing the line route from others utilities, high trees, etc. and preparation area for placing drum and winch / puller. :

Ø  lnstall bamboo scaffolding to cross housing, electrical over head lines, roads and other objects.

Ø  Prepare Drum Place, Winch place and the access roads to transport conductors and equipments.

·           Transport Material

Transport stringing materials including :

Ø  Conductors ACSR to drum place area.

Ø  Earth wire OPGW and GSW wire to drum place.

Ø  Running Out Blocks to each tower location in stringing section.

Ø  lnsulators and fittings to each tower location.

Equipment for transport material :

Ø  Truck Crane.

Ø  Truck 8 tons

Ø  Tools set

Ø  Slings and wires

Numbers of drums of conductors should be according to amount ofthe required lengths

·           Equipment & Tools

Make sure that all equipments and tools have been checked properly and are ready and save to be used. The tools prepared including all tools for safety of the workers and also the materials / equipments needed for the operation.

Note : Numbers of drums of conductors should be according to the required lengths.

·           Safety Meeting

Always before starting to work, the supervisor and his foreman must perform Safety Tool Box Meeting with their own crews. Safety Tools boxmeeting should consists of following tasks :

Ø  The Task and target of the respective date work.

Ø  Checking safety tools for workers and the equipments.

Ø  Checking healthy and conditions of workers and equipments.

List for safety tool

Ø  Safety Belts

Ø  Measurements

Ø  Working schedule

Note : The task of the foreman of each crews to check and direct responsible for safety of the workers and the equipments.

2.       INSTALLATION OF INSULATORS

Insulators, running out blocks and the fittings transported to each towerlocation and lifted carefully by winch and rope. Be sure that the insulators type installed are according to tower schedule for each tower type. Numbers of string of insulators and the plate should be installed accordingto tower schedule and fixed to the cross arm points.

List material :

Ø  Small winch 3 tons

Ø  Rope 150 m

Ø  Tool keys

Ø  Truck

Note : Numbers of drums of conductors should be according to the required lengths.

3.       INSTALLATION OF RUNNING BLOCK

Running block for conductors will be fixed to the yoke plate and lifted together with the insulator strings to the fixing points. Running block forearth wire lifted until EW cross arm.

4.       ANCHORAGE

Towers at temporary termination should be supported with steel wire ropes dia. ± 13 mm as an anchor of the towers - The wires attached at the each cross arm should be anchored to the ground to a concrete block counterweight. Angle of the wires from the ground surface to the fixing point should be maximum 45 degree.

Note : Make sure that the steel wire rope not damage the surface galvanize of the tower steel.

5.       PULLING PILOT WIRE

The first stage string is to pull pilot wire for the earth wires OPGW and GSW wire in a single running out block.

Ø  Pulling the pilot wire starting from drum place (tensioner) to to the winch at the winch place.

Ø  ln every towers, the pilot wire placed in the middle of running block wheel and started from top cross arm conductors.

Ø  Pulling pilot wires, started from diameter min 6 mm [pull manually] by winch pulling with 6mm wire the bigger size [ min 10 mm ], with 10mm pulling 18mm wire and with 18mm pulling conductor twin bundle in one time.

6.       PULLING EARTHWIRE & CONDUCTOR

ln case the pilot wire has been completely pulled and connected to both sides [winch and tensioner], pulling conductors can be carried out with positions asfollows :

Ø  Middle wheel used for pilot wire.

Ø  The other two wheels used for each line conductor.

Foreman must care with running conductors from the each drums. Stop and run must be harmonic with the operation of tensioner machtine. Communication between both sides and also each towers watchman must be really good to secure the line running properly in the machine and running block until the end.

Before start pulling earth wire and twin conductors, ensure that operator of winch and tensioner can communicate each other to start pull or to stop /brake and operator tensioner should always try to keep the line in the allowable clearance during the pulling and or in the brake situation.

Ø  Length of the conductor in drum should have nearly the same length tobe able to place the compression joint at same.

Ø  Pulling conductors must be carried our from the top cross arm then to middle and finally to the bottom cross arm.

Ø  Lines man at tension tower with strong uplift must care with condition of cross arm and position conductor running in the wheels. He should always report to the supervisor / foreman to inform that all running safely.

Foreman must supervise to the worker who making the compression joint and ensure the joint has been made properly.

7.       TERMINATION PULLING

When the earth wire and the conductors reach the winch machine, pulling should be stopped and terminated. Earth wire and the conductors must be clamped and waiting for some ours [usually 24 hours ] before sagging undertaken progressively from one to the other end of the stringingsection.

8.       SAGGING

After pulling is completed , sagging of earth wire and conductors can be carried out according to the sag chart and sagging operation record as attached.

Procedure calculation measurement for sagging can be applied into two method of sagging depending on the line profile of the section.

ln general the method sagging rneasurement are :

Ø  Using sag level [ applied for flat area ].

Ø  Using tangent sag [ applied for terrain area ].

Foreman should ensure that sagging done properly. Only the experience workers allowed to do this sagging.

9.       FITTING & CLAMPING

When the conductors are properly adjusted according to sag chart, conductors should be moved one by one from the running block wheels to the respective clamps of the insulators / earth wire flttings . lnstallation of armour rod in the suspension strings and also cutting conductors in the tension string must be prepared and done properly to avoid damage of conductors and losses in the sag.

10.   INSTALLATION OF ACESSORIES

After step 8 completed, accessories can be installed.

Ø  Vibration dampers for earth wire and conductors.

Ø  Spacer damper for twin conductors. Installation method should follow technical specification.

Ø  Install jumpers and spacer jumpers including counter weight.

11.   RECORDING

Recording is required during the stringing, mainly for the record of :

Ø   lnstalled conductors , record the drum number and length.

Ø  Sagging measurement actual and plan for conductors and earth wires.

Ø  Using compression joint or repair sleeve (if any) and the position in span.

Ø  Numbers and Type of all accessories installed in that line.

List document for recording.

Ø  STRINGING RECORDING.

Ø  SAGGING PROTOCOL.

Ø  OVER CROSSING RECORD.

Ø  JUMPER INSTALLATION PROTOCOL

All of data recordings will be used for Final Check lines.

12.   PULLING OPGW

Method for stringing OPGW nearly similar with pulling earth wire & Conductors. The difference is the joints (joint box) of the OPGW must be placed and the determine tower (suspension or tension type) approximately 5 Meters (or as otherwise agreed by Engineer) above the ground level . Splicing OPGW at Joint Box must be carried out by very experienced persons who well trained in this optical wire and then losses must be measured  in order to check qualityof the joint. During pulling OPGW, special attachments with weight should be used as intermediate between pilot wire and OPGW to avoid twisting effect which can damage the optical wire inside. To be noted to avoid bending < 60 degree which can damage the optic wire during pulling.

The supervisor and foreman should determine where the OPGW will be terminated for joint position before pulling. For joint purpose , additional length required for splicing and will be placed in the joint device. To avoid damage, pulling OPGW must use special tensioner where the wheels (capstan) diameter >800 mm.