·
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.
