Transmission Line
Construction Workmanship
1
TABLE OF CONTENTS
1 GENERAL OF THE TRANSMISSION LINE
2 FOUNDATION WORK
2.1 FLOW CHART TO THE FOUNDATION WORKMANSHIP 2.2 LINE CHECK-SURVEY 2.3 FOUNDATION LAY-OUT
2.4 FOUNDATION EXCAVATION
2.5 REQUIREMENTS OF THE MATERIALS 2.6 FORMWORKING
2.7 CONCRETE POURING
2.8 CURING AND BACKFILLING 2.9 GROUNDING INSTALLATION
2.10 CAUTIONS FOR SAFETY PURPOSE
3 ERECTION WORK
3.1 FLOW CHART TO THE ERECTION WORKMANSHIP 3.2 PREPARATION BEFORE CONSTRUCTION 3.3 TOWER LEGS ERECTION 3.4 GIN POLE ERECTION
3.5 TOWER PARTS SUSPENDING
3.6 GIN POLE DEMOLISH, BOLTS FIXING AND SITE
CLEARING
3.7 SAFETY CAUTIONS
4 STRINGING WORK
4.1 FLOW CHART TO THE SERINGING WORK 4.2 GENERAL
4.3 PREPARATION BEFORE STRINGING 4.4 CONDUCTOR PAY OUT 4.5 SAG
4.6 ACCESSORIES INSTALL 4.7 OPGW SUSPENDING
2
1 GENERAL OF THE TRANSMISSION LINE
1.1 138kV Leyte-Bohol transmission line starts from Ormoc Substation and
ends in Maasin Substation, there is a new creation of 113.86km line consisting of 313 new towers/poles.
1.2 Direction of the Line and Foundation Series:
MAASIN S/S Forward
B C
A D
ORMOC S/S Backward
2 FOUNDATION WORK
2.1 FLOW CHART TO THE FOUNDATION WORMANSHIP
Pre-work 施工前准备Line Preparation Check-survey Check-survey 复测、分坑 & Lay-out Calculation 分坑测量 & Lay-out Fabrication of Excavation 土石方开挖Re-bars 钢筋加工 Formwork Concrete Pouring 基础浇浇制 & Grounding Installation Concrete Pouring Backfilling 3
2.2 LINE CHECK-SURVEY
Curing & formwork Ohmer Measuring Dismantlement for the Grounding Prior to construction, Structure List and Plan and Profile shall be followed in the verification of angles of deflection, spanning and leg extensions,etc; due to the tree-laden situation of the transmission line, and in order to ensure the accuracy of check-survey, GPS(Global Positioning System) will be employed for such purpose.
Figure 2-1 GPS Check-survey by Professionals
2.3 FOUNDATION LAY-OUT
2.3.1 Through the whole line, theodolite will be used in foundation lay-out.Center
Line points will be staked out by the theodolite, and four 45°reference points will be marked for the four pits to facilitate formworking.(namely 45° reference point)
2.3.2 Lay-out Illustration(Figure 2-2)
4
2.4 FOUNDATION EXCAVATION
2.4.1 Pit will be excavated manually or mechanically. Forward Center Line
45°Point
45°Point GP B C EP
Center Hub
A D
45°Point 45°Point
Backward Center Line
Instruction：GP——distance between the center hub and the farthest point of the
pit, furnished by Design Department;
EP——distance between the center hub and the nearest point of the
pit, furnished by Design Department;
Figure 2-2 Planform of the Foundation Lay-out
2.4.2 In the case of soft soil like the rice field location, shoring shall be placed and
strengthened enough to ensure the security of persons working in the pit.(Figure 2-3)
2.4.3 In the case of strong current coming up from underground, water pump shall
be employed until designed pit depth has been achieved, and concrete lean shall be placed as soon as the excavation has been finished.
5
Figure 2-3 Shoring Facility 2.5 REPUIREMENTS FOR THE MATERIALS 2.5.1 Requirements for Cement
2.5.1.1 Cement quality shall be in compliance with the latest requirements
of the Standard Specifications for Portland Cement(ASTM C-150);
2.5.1.2 Grand, APO, Union shall be optional sources for subcontractors to
choose cement manufacturer for their approved quality by TRANSCO;
2.5.1.3 Moisturized and agglomerated cement shall be prohibited from any
use in foundation works;
2.5.1.4 Cement piling place shall be dry and ventilative, storing period
shall not exceed 30 calendar days and cement overlapping height shall be within 14 bags.
2.5.2 Requirements for Coarse Aggregate (Gravel)
2.5.2.1 Gravel shall conform to the requirements of the latest edition of
ASTM C33 and shall consist of hard, durable and uncoated particles which are reasonably free from thin, flat or elongated particles in all sizes and well graded. The diameter should conform to continuous grid.
6
2.5.2.2 Standards followed for Gravel Testing as below:
Sieve Designation U.S. Std. Square Mesh 2″ 1-1/2″ 1″ 3/4″ 1/2″ 3/8″ Cumulative Percentage By Weight Passing（%） 100 95-100 - 35-70 - 10-30 2.5.3 Standards Followed for Sand Testing as below:
Sieve Designation U.S. Std. Square Mesh 3/8″ NO.4 NO.8 NO.16 NO.30 NO.50 NO.100 NO.200 2.5.3.1 Sand from the sea is strictly prohibited from any use in work
mentioned herein; source selection of gravel and sand shall be as follows for their approved quality by TRANSCO:
EBR Crusher Plant，ALLOSA Crusher Plant ，JESSICA Crusher Plant，MC BUILDERS Crusher Plant ，CODILLA Crusher Plant，
Cumulative Percentage By Weight Passing（%） 100 95-100 80-100 50-85 25-60 10-60 2-10 0-3 7
HILONGOS Crusher Plant，BALTUNADO Crusher Plant。
2.5.4 Requirements for Water
2.5.4.1 Water for preparing concrete and mortar shall be clean, fresh,
and free from organic and/or inorganic matter in solution or suspension insuch amounts that may impair the strength or durability of the concrete; no seawater or water from excavations shall be used and water shall be stored in clean containers;
2.5.4.2 The requirements of ACI shall be applied. 2.5.5 Requirements for Reinforcing Steel
2.5.5.1 All reinforcing steel shall comply with criteria specified in the
drawing and conform to the requirements of ASTM A615 Grade 60; 2.5.5.2 Surface of reinforcing steel shall be free from dirt, impairment,
oily filth and pollution, and no steel with growth, defects or local rusting on its surface shall be used in foundation work;
2.5.5.3 The reinforcing steel shall not be placed on ground directly without
any cushion between the reinforcing steel and the ground.
2.6 FORMWORKING
2.6.1 Stub-angle setting can be undertaken on the basis of a single pit, and
formworking and pouring can be executed pit by pit respectively, or four pits undertaken simutaneously;
2.6.2 Formwork dimensions shall be computated within the scope of one pit; 2.6.3 Computation formula for stub-angle and formwork dimensions: L1= L2 – L×Sinα L2= FP + √2 E0×Cos α
LA1= AP +(√2 b/2)×Cosα- H2 tgα LA2= AP -(√2 b/2)×Cosα- H2 tgα LB1= FP +(√2 b/2)/Cosα- H1 tgα LB2= FP -(√2 b/2)/Cosα- H1 tgα
8
L1 Distance between Center Hub and upper point of Stub-angle L2 Distance between Center Hub and bottom point of Stub-angle LA1 Distance between Center Hub and upper farthest point of Chimney LA2 Distance between Center Hub and upper nearest point of Chimney LB1 Distance between Center Hub and bottom farthest point of Chimney LB2 Distance between Center Hub and bottom nearest point of Chimney GP Distance between Center Hub and farthest point of Pad EP Distance between Center Hub and nearest point of Pad H1 Height from Bottom Level of Chimney to Bottom Level of Pad H2 Height from Center Point of Chimney Bare Part to Ground Level b Dimensions of Chimney Sectional Surface FP Distance between Center Hub and Center of the Pit
AP Distance between Center Hub and Convergent Point of Center of Chimney
and Ground Level
α Angle of Stub-angle Inclination
2.6.4 Stub-angle and Formwork Dimensions (Figure 2-4, Figure 2-5)
L1 Center line LA1 LA2 Ground Level H2 H1 EP LB2 L2 9 LB1 GP
Figure 2-4 Profile of Formwork Dimension
FP Center Hub EP LA2 L1 LB2 LA1 L2 LB1 GP Figure 2-5 Planform of Formwork Dimensions
2.6.5 Parameter L1 and stub-angle gradient shall be calculated twice and the errors
between two computations shall fall within 1‰ of the calcuated values respectively;
2.6.6 During formworking, specification and length of stub-angle shall be inspected
to avoid misusing;
2.6.7 Due to the 100mm difference between the bottom of the stub-angle and the
bottom of the pit, and in order to fix the stub-angle, a concrete block shall be placed under the stub-angle, of which the strength shall exceed that of the foundation.(refer to Figure 2-6)
2.6.8 In order to adjust parameter L1 and stub-angle gradient conveniently, flange
bolt and turn buckle shall be employed;(refer to Figure 2-7)
10
2.6.9 Formwork for the chimney shall be firmed enough to hold the concrete pouring. 2.7 CONCRETE POURING
2.7.1 Prior to pouring, concrete pouring permit shall be prepared and
representatives from TRANSCO be informed;
2.7.2 Mechanically mixing and vibrating shall be adopted in concrete pouring; 2.7.3 Prior to pouring, the depth of the pit, stub-angle dimensions, and
specifications and quantities of re-bars shall be verified.
Ground level stub
HG
Concrete block
Figure 2-6 Concrete Block Placement
Flange Bolt Stub 11
Figure 2-7 Overlook of Stub-angle Fixing and Adjusting Facility
2.7.4 Prior to concrete pouring, Insepection for aggregates, sand, cement
and water,etc.shall be applied, specifications and quantities of said materials shall comply with requirements mentioned hereof; 2.7.5 Mixting time shall not last less than 1-1/2 minutes;
2.7.6 For pouring one leg one time, 3 cylinder samples shall be prepared,whereas 6
samples shall be made for pouring 2 legs and above at one time. Tower No., leg series and pouring date shall be born on each sample;
2.7.7 Concrete falling from the mixer shall travel no more than 2 meters，otherwise
chuting facility shall be used.(refer to Figure 2-8)
Figure 2-8 Chuting Facility
2.8 CURING AND BACKFILLING
2.8.1 3 hours after the completion of pouring, curing measures shall be
applied by watering, and watering can be excepted in rainy days;
12
2.8.2 14 days after the completion of concrete pouring, the pit shall be
backfilled,backfilling permit be submitted beforehand and TRNASCO representatives be informed to supervise such activity;
2.8.3 In backfilling, the soil shall be compacted layer by layer, and every
50 cm the soil shall be compressed. Backfilled soil strength shall reach 95% of its original one.
2.8.4 The maximum diameter for the particles used in backfilling shall not exceed 8 cm. 2.9 GROUNDING INSTALLATION
2.9.1 Grounding ohmic value shall not be higher than 10Ω for each tower
of which however, tower No.1 to tower No.9，and tower No.307 to tower No.310 shall not exceed 5Ω;
2.9.2 Prior to pouring, grounding rod typed ST-G1 shall be installed for leg A and leg
C respectively according to design drawings(refer to Figure 2-9);in case ST-G1 grounding rod can not match the required ohmic value, the ST-G2 grounding rod shall be installed instead.(refer to Figure 2-10)
TERMINAL CONNECTOR
GALVANIZED STEEL WIRE SPLICING SLEEVER GALVANIZED GROUND ROD
Figure 2-9 GROUND TYPE ST-G1
13
④ 15m 15m 45° 45°
0.6m ① 16m ② ②③
③ ④ ①GALVANIZED STELL WIRE ②SPLICING SLEEVER ③GALVANIZED GROUND ROD ④TERMINAL CONNECTOR
Figure 2-10 GROUND TYPE ST-G2
2.10 CAUTIONS FOR SAFETY PURPOSE
2.10.1 In the case of soft soil like rice field location, during construction,
shoring facility shall be placed and strengthened enough to avoid any accident.
2.10.2 In the case of construction site been located near a village or
along a road, right after the start of construction should warning signs and seclusion fences be pitched and said facilities shall not be demolished untill backfilling is finished.
2.10.3 During hauling by vehicles, aggregates shall be covered to avoid
any injury caused by falling of aggregates; 2.10.4 Avoiding any improper tampering with electricty;
2.10.5 Adequate lightening facilities shall be enforced during night construction.
14
3 ERECTION WORK
3.1 FLOW CHART TO THE ERECTION WORKMANSHIP
Technical Preparation
Preparation before Construction Human Resources
Preparation Hauling and check of tower materials Tower leg erection Tools and equipments preparation Site Preparation
Gin Pole Erection Tower Body Suspending Tower Parts Suspending Cross Arm Suspending Gin Pole Demolish Bolts Fixing and Site Clearing
3.2 PREPARATION BEFORE CONSTRUCTION
3.2.1 Until foundation leg spans, differential heights, and slop are carefully checked
and pass, the construction can not begin.
3.2.2 In hauling tower parts, tower parts should not miss and damage. Necessary
15
Safety Measures must be applied in hauling.
3.2.3 The tower parts at site must be checked amount and type based on related
tower drawings. If any distortions and discrepancies between specifications, adjustment and changing must be proceeded.
3.2.4 The appearances of all tools and equipments used in erection must be checked.
Any equipment which does not reach the specifications must not used in construction.
3.2.5 Any substances will influence the safety of suspending and construction, for
instance trees, rocks, power lines and etc., must be get rid of ( including power cut ).
3.2.6 No erection work on any tower / pole founded on concrete shall be started
within seven days after the concrete footings for the tower / pole have been completed.
3.2.7 Before erection, technical, safety and quality explanation must be conducted to
construction personnel. 3.3 TOWER LEGS ERECTION 3.3.1 Tower legs will be erected manually.
3.3.2 When the tower part aimed the stub angle, make the tower part vertical
manually, locate the bolt hole and then connect the bolts and nuts by tip wrench.
3.3.3 After finish installing four pieces of main tower parts, connect three sides of
main tower parts by tower materials. Left one side open for erection gin pole. 3.4 GIN POLE ERECTION
3.4.1 After finish erection of tower legs, three sides already joined into one part. One
side open and the gin pole will start erection here. Please refer to figure 3-1. 3.4.2 In erection gin pole, manually suspend the top of gin pole a little to help the
erection. Check band will be used on bottom of the gin pole.
16
Connected Tower Parts
Pulley
Side Pull Wire Gin Pole
Backside Pull Wire Pulley Side Pull Wire To Winch Figure 3-1 GIN POLE ERECTION
3.5 TOWER PARTS SUSPENDING 3.5.1 Figure of tower parts suspending
Pulley
Gin Pole
Suspending Steel Wire Upper Pull Wire
Tower Parts Down Pull Wire
Control Wire
To Winch 17
Adjustment Connected Tower Parts
Figure 3-2 TOWER PARTS SUSPENDING 3.5.2 The payload of the gin pole is 1.4 tons
3.5.3 Gin pole should be installed in the center of tower and a little slop in the
reverse suspending direction. The distances between upper pull wire tie point and top of gin pole should be less than 0.7 time of gin pole height.
3.5.4 The highest tie point of upper pull wire should be lower than main tower parts
joint points. The down pull wire should be tied in the upper of the joint points of main tower parts.
3.5.5 When in suspending DA, DB, DC and DD 10 section tower parts, reinforce
lumber will be used to reinforce. The reinforce lumber should tie hard to main tower parts.
3.5.6 Tower body and grounding top parts are suspended through gin pole. Cross
arm can be suspended through installed grounding top parts ( Figure 3-3 ). 3.5.7 When in emplacement of tower parts, first emplace lower part and then
emplace higher part. After installing one to two bolts in lower parts, adjust another part joint parts.
3.5.8 Suspending wire must be tied on the point higher than the center of gravity. 3.5.9 After finish suspending one section of tower body, all accessories should be
installed and fixed by bolts. Then elevate the gin pole. After elevation, start suspending of next section tower parts. Elevation system Figure 3-4. 3.5.10 When in elevation, at least two rings are needed. After the gin pole elevated to
wanted position, make the four loosen upper pull wires twist tied. Go on elevation until the tightness of upper pull wire and then tie down pull wire. After these operations, loosen the suspending wire and rings.
18
Suspending Steel Wire
Control Wire
To Winch
Figure 3-3 GROUNDING TOP PARTS SUSPENDING
19
Gin Pole
Ring
Installed Tower Body
Elevation Steel Wire
To Winch
Figure 3-4 GIN POLE ELEVATION SYSTEM
3.6 GIN POLE DEMOLISH, BOLTS FIXING AND SITE CLEARING
3.6.1 When in demolishing the gin pole, suspending steel wire tie the top of gin pole
and then put down it slowly. Break down the gin pole must be conducted at ground.
3.6.2 After demolishing of the gin pole, all bolts and nuts in tower must be carefully
checked one by one to ensure fixing.
3.6.3 After all erection work finished, then go on clearing tower site. Hauled the
equipments, tools and excess materials out of tower site. 3.7 SAFETY CAUTIONS
20
3.7.1 If the wind grade higher than six or in thunderstorm, construction at tower is
forbidden.
3.7.2 The small tools should not replace the big one.
3.7.3 Force erection is forbidden. Any problem met in erection, reasons must be
found out.
3.7.4 Safety helmet must be worn when get into tower site. When in high altitude
construction which means 2 meters higher than ground, safety wire must be used in right way.
3.7.5 Temporally failed installing tower parts should not be put in tower parts or one
parts connected while another part not to prevent from the stepping down events.
3.7.6 High altitude construction personnel should not climb the tower parts not finish
installing. Suspending wire must be demolished after the tower parts are emplaced.
3.7.7 Hand on the tools in tower and cast the materials are forbidden.
3.7.8 Safety sign and other accessories must be installed as the design request after
tower erection.
21
4．STRINGING WORK
4.1 FLOW CHART TO THE STRINGING WORKMANSHIP
Supplementary String Workmanship Prescribe Cross Over Shelf Set Up Scheme
Technical Preparation Technical Explanation Construction Materials Test Materials Preparation Preparation Before Construction Conductor and Grounding Conductor Joint Test Equipments and Tools ROW Preparation Preparation Suspend Stringing Pulley Site Preparation Puller and Tension Site Preparation Puller Wire Paying Out Sagging Site Stake Preparation Conductor Pay Out Conductor Connection Faradic Electricity Protection Conductor Tensioning Compression Joint Operation Suspension Tower Sag Sagging Sagging Operation Tension Tower Sag Sag Survey Tension Tower Conductor Install High Altitude Conductor Marking Operation Suspension Tower Accessories Accessories Install Jumper Connections 22
4.2 GENERAL
4.2.1 String work is from ORMOC to MAASIN substation. Newly constructed
single circuit three phases conductor has 110.397 km and double circuit has 3.613 km ( #119 - #126 ). String one circuit of OPGW.
4.2.2 The type of conductor is 795MCM and between Tower No. 119 and Tower No.
126 will be stringed another circuit of 336.4MCM conductor.
4.2.3 Before construction, the strength of concrete in string section must reach 28
days concrete strength; any defects influencing the stringing are not exist; towers needing reinforce are already done.
4.2.4 Conductor, conductor hardware and any other construction materials must
reach the design specification.
4.2.5 Equipments and tools must reach the construction requirements.
4.2.6 Except there is special construction scheme to keep the safety, pay out puller
wire and any other wire under the electrified wire is forbidden. 4.3 PREPARATION BEFORE STRINGING 4.3.1 Technical Preparation
4.3.1.1 Before stringing, related construction manual must be prescribed.
4.3.1.2 All construction personnel must familiar with the construction drawings and
documents.
4.3.1.3 Before stringing, landform, crossover, transportation, tower site and etc. along
the tower should be fully known. Recheck the important crossover substances height and location; span and differential height of the two towers which will be used to survey sag.
4.3.2 Materials, Equipments and Tools Preparation
4.3.2.1 Check whether hole, length of conductor and capacity of conductor reel matche
back carriage.
4.3.2.2 Check the conductor hardware type, quantities, and dimension; assemble it
tentatively.
23
4.3.2.3 Before construction, conductor compression joint test must be conducted as the
requirements.
4.3.2.4 Appearances of the equipments and tools must be checked and if not reach the
specifications, these kinds of equipments and tools can not be used. 4.3.3 ROW Preparation
4.3.3.1 Scope of the ROW: Fifteen meters either way from center line is in the scope
of the ROW. ( Figure 4-1)
TOWER
15m 15m
Center Line 15m TOWER 15m
Figure 4-1 ROW SCOPE
4.3.3.2 ROW issue such as houses, power line, communication line and etc. must be
solved before stringing.
4.3.3.3 Trees and grass in ROW must be cleaned up.
4.3.3.4 Cross over shelf should be used if the conductor will cross over the high way,
towers and important communication lines.When cross over the road and river, assign the specified personnel to watch. 4.3.4 Pulley Suspend in Stringing
4.3.4.1 In common situation, single pulley will be suspended.
4.3.4.2 When the angle of tension tower is more than 30 degree, double pulley will be
suspended.
4.3.5 Puller and Tension Site Preparation
4.3.5.1 Take into consideration whether it need joint conductor in this span.
24
4.3.5.2 The site should be capacity enough for puller, tension, crane, construction
materials and operation equipments.
4.3.5.3 Backside nearby tower is suitable for sagging and stake wire operation. 4.3.5.4 Puller and Tension Site Arrangement Figure 4-2
Stake
Center Line
Pull Wire
Stake Puller
Double Buckle
Figure 4-2 Puller and Tension Site Arrangement
4.3.6 Faradic Electricity Protection
4.3.6.1 When in tensioned pulling the conductor, earthing pulley must be used on both
conductor input and output point. After finish pulling, temporarily earthing wire must be connected.
4.3.6.2 When operator’s activities are in scope of 0.6 meters from the conductor,
earthing wire must be connected before work. The one who installed eathing wire will demolish the earthing wire.
4.3.6.3 When connecting the earthing wire, connect the earthing point first and then
conductor point; when disconnect the earthing wire, disconnect the conductor point first and then earthing point.
4.3.7 When all preparation work finished, filling in the stringing permit and then
25
inform Transco. 4.4 CONDUCTOR PAY OUT
4.4.1 Pull wire will be paid out manually. If there is no safety measures, that pull
wire cross under the electrified wire is forbidden.
4.4.2 In the process of pulling, if the conductors pass by the tower, village, important
transportation intersection, and river, assign specified personnel monitor. The personnel must closely monitor the pulling status. The communication must be smooth in pulling section.
4.4.3 The connection between two pull wires must be strong. Also between the pull
wire and conductor.
4.4.4 If the pull wire will be elevated higher than the pulley, press conductor pulley
must be used like Figure 4-3. Specified personnel must be available to ensure the wire will not jump out of the pulley. Press conductor pulley will be installed at the point 3 to 5 meters from the string pulley.
Tower Conductor May Elevate Pull Direction Pull Wire Press Conductor Pulley Chain Block
Figure 4-3 PRESS CONDUCTOR PULLEY
4.4.5 Walkie -Talkie will be used in sagging. Generators will be used at respective
puller and tension site.
26
4.4.6 Conductor pay out sequences: first upper phase; second middle phase; last
down phase. 4.4.7 Compression Joint.
4.4.7.1 Hydraulic compression joint will be applied to connect two conductors. 4.4.7.2 The distances between joint sleeve and tower should be less than 15 meters. 4.4.7.3 No joints will be permitted in span crossing over or adjoining important
highways or other public utilities. River crossing spans shall also be free from joints.
4.4.7.4 Filler past should be applied. 4.4.8 Repair Sleeves
4.4.8.1 The minimum distance between two repair sleeves or between a repair sleeve
and a splicing sleeve shall not be less 366 meters.
4.4.8.2 At the location of the damage on the conductor to be repaired, not more than
one third of the outer aluminum strands are damaged over a length of not more than ten cm.
4.4.8.3 Not more than two strands in the outer layer are broken, no strand in the inner
layer of aluminum strands are broken, and the cross section area of any other of the damaged strands is not reduced by more than twenty five percent. 4.4.9 As soon as finish pulling one phase conductor, fix the conductor immediately.
Also ensure clearance between the conductor and substances crossed over. Then proceed to next phase pulling. 4.5 SAG
4.5.1 Before sagging, pay more attention to site arrangement, stake imbed, tools
selection, conductor joint, defect solve and splicing joint distance to tower. 4.5.2 Sag Survey ( Span Point Measure and Parallelogram Measure ) 4.5.2.1 Span Point Measure
Theodolite should be set at span point ( Figure 4-4 ) 4.5.2.2 Parallelogram Measure
If the span is very short, the Span Point Measure can not be applied in survey
27
for the short sag. So we will use parallelogram measure to survey( Figure 4-5 ).
L
h b
a
θ
Theodolite
b=(2√f -√a )2
θ=arctg(tgα-b/L)
h is actual differential height between two conductors suspension points. αis prior measured differential angle of suspension point. a is differential height between the center of theodolite lens and measured conductor suspension point. L is span.
Figure 4-4 SPAN POINT MEASURE TO SURVEY THE SAG
b f a
28
Figure 4-5 PARALLELOGRAM MEASURE
4.5.3 Suspension Tower Sagging 4.5.3.1 Suspension Tower Sagging Figure
N2 Sagging Site A DA N1 GA Conductor Fix Stake
Figure 4-6 SUSPENSION TOWER SAGGING FIGURE
4.5.3.2 Temporarily pull wire will be installed to tension tower N1 as the specification.
Insulator, hardware and conductor shall be suspended to tower N1. 4.5.3.3 Loose the ground conductor fix wire DA. 4.5.3.4 Begin sag survey.
4.5.3.5 Sagging site A begin to sag the conductor.
4.5.3.6 When the sag reaches the wanted value, mark operation will proceed on the
conductor. Tight ground conductor fix wire DA again and immediately install high altitude fix conductor wire GA. 4.5.4 Tension Tower Sag
4.5.4.1 Tension tower sag(Figure4-7)
4.5.4.2 Installed temporarily pull wire on tension tower N.
29
4.5.4.3 Tight the conductor at site C to survey the sag.
4.5.4.4 Adjust the sag to reach the design request and conduct mark operation on
tower.
N Site C Tight
Temporarily Pull Wire
Site B
Conductor Fix Stake
Figure 4-7 TENSION TOWER SAG
4.5.4.5 In tension tower N, proceed high altitude conductor fix; If the mark operation
is in ground, proceed ground conductor fix and then conduct compression joint and suspend the conductor. 4.6 ACCESSORIES INSTALL
4.6.1 Before install the accessories, conductor must be fully earthing.
4.6.2 When install the accessories, safety rope must tie on cross arm. Twist on
insulator is forbidden.
4.6.3 Climb the insulator is forbidden.
4.6.4 After elevate the conductor, armor rods should be installed immediately and
then install the clamps. After that, demolish the pulley and make the clamp fully connect insulator. Loose the double buckle slowly and make the insulator bear the whole weight of the conductor. In the end, demolish the elevation tools.
4.6.5 Jumper connection should be installed finely; sag of the jumper connection
should reach the design requirement.
4.6.6 Where it becomes necessary to shift the point of attachment after the armor
rods were installed, such shifts not exceed sixty five mm either way from
30
center.
4.7 OPGW SUSPENDIN
4.7.1 Pay out, sag, and suspension of OPGW workmanship are the same conductor
operation.
4.7.2 Before construction, manual of the factory must be available and suspend as
the manual request.
4.7.3 Connection sequences of the pull wire and OPGW ( Figure 4-8, Figure 4-9 and
Figure 4-10 ). It will prevent the OPGW from twist.
⑥ ⑤ ④ ③ ② ①
FIGURE 4-8 PULL IN NORMAL STATUS
① ② ③ ④ ⑤ ⑥
Figure 4-9 CONNECT STEEL WIRE TO END OF OPGW
① ② ③ ④ ③ ② ①
Figure 4-10 PULL TWO CONNECTED OPGW
① OPGW ② Connection Jacket ③ Bend Resist Connection ④ Twist Resist Utility ⑤ Rotate Connection ⑥ Pull Wire
4.7.4 When install the OPGW accessories, come along and double buckle must be
31
used to tight the OPGW. After demolish the pulley, remove the come along and double buckle slowly. When the OPGW bears a little strength, stretch the OPGW like Figure 4-11 broken wire shows. After that, install the armor rod and clamp.
①
②
⑤ ③ ④
Figure 4-11 OPGW ACCESSORIES INSTALL
① Cross Arm ② Double Buckle ③ Come Along ④ OPGW ⑤ Pulley
4.7.5 Test immediately after suspending the OPGW. 4.7.6 After the test pass, melt joint of the OPGW.
32
因篇幅问题不能全部显示，请点此查看更多更全内容