Tes p-122.07-r0

PAGE NO. 2 OF 19TESP12207R0/MAA
TRANSMISSION ENGINEERING STANDARD TES-P-122.07, Rev. 0
Date of Approval: October 18, 2006
TABLE OF CONTENTS
1.0 SCOPE
2.0 PLAN AND PROFILE DRAWINGS
2.1 General
2.2 Drawing Preparation
2.3 Features of Plan and Profile Drawings
3.0 SAG TEMPLATES
3.1 General
3.2 Sag Template Curves
3.3 Sag Template Design
3.4 Sag Template Construction
4.0 STRUCTURE SPOTTING
4.1 General
4.2 Preparation for Structure Spotting
4.3 Preliminary Reconnaissance of Plan and Profile
4.4 Structure Spotting Procedure
4.5 Crossings
4.6 Insulator Sideswing
4.7 Grading and Uplift
4.8 Dead-ending
4.9 Structure Numbering
4.10 Other Considerations
4.11 Drawing Check and Review
4.12 Structure List
5.0 BIBLIOGRAPHY
FIGURE TE-2207-0100-00 Typical Sag Template
FIGURE TE-2207-0200-00 Check for Uplift

1.0 SCOPE
This Standard establishes procedures for the preparation of the plan and profile
drawings and sag templates that are used to locate structures on a transmission line
route, so as to ensure that the structures are used within their design capacity and that
the transmission line provides adequate clearance to ground, to the structure itself, and
to objects traversed by the transmission line.
2.0 PLAN AND PROFILE DRAWINGS
2.1 General
The transmission line plan and profile drawings serve an important function in
linking together the various stages involved in the design and construction of
the line. Initially the drawings are prepared based on a line route survey to
show the location and elevation of all natural and manmade features to be
traversed by the proposed line and location of features adjacent to the proposed
line. The drawings are then used to complete the line design work such as
structure spotting. During material procurement and construction, the
drawings are used to control purchase of materials and serve as construction
specification drawings. After construction, the final plan and profile drawings
(as-built drawings) become the permanent record of property and right-of-way
data, useful in line operation and maintenance or future modifications.
Accuracy, clarity and completeness of the drawings shall be maintained,
beginning with initial preparation, to ensure economical design and correct
construction.
2.2 Drawing Preparation
Adequate control of field survey, including ground check (in case of aerial
survey) and proper translation of data to the plan and profile drawings are of
utmost importance. Errors which occur during the initial stage will affect the
transmission line design because a graphical method is used to locate the
structures and conductors.
2.2.1 Plan and Profile drawings shall be drafted on SEC Standard drawing
sheets, per SEC Engineering Drawing Standard SEEDS-II.
2.2.2 The drawings shall be prepared with a horizontal scale of 1 cm = 20
meters and a vertical scale of 1 cm = 2 meters.
2.2.3 Start the plan and profile drawing so that stations which are multiples
of 20 meters will coincide with the vertical lines of printed portion of
the sheets. Increase in stationing and structure numbering shall
proceed from left to right with the profile and corresponding plan
view on the same sheet. The change in station (station equations)
shall be avoided as far as possible. Profile stationing shall start from

the proposed power source increasing towards the supplied point.
Usually the source point is a take-off point, a first P.I (point of
intersection) or a tap point. The value of the starting profile stationing
shall be selected such that negative stationing values shall be avoided
in case of adjustments.
2.2.4 Horizontal ground distance shall be used in computing profile
stationing. When an identical distance is observed by a controle
traverse, the profile stationing shall be adjusted proportionately.
2.2.5 Angles at crossing with powerlines, pipelines, railroads, fence, etc., if
not measured in the field shall be computed from the available data.
2.2.6 Elevation of instrument stations may be computed reciprocal
trigonometric observations.
2.2.7 Elevation shall be adjusted to previously accepted values for identical
profile stationing. The forward direction shall be the direction of
increasing profile stationing.
2.2.8 The atmospheric and earth curvature correction shall be applied to
trigonometric elevation computations.
2.2.9 When change of station occurs (station equation), continue the profile
line using the forward station so that stations which are multiples of
20 meters will coincide with each vertical line on the plan and profile
sheet.
2.2.10 Each plan and profile sheet shall end with a station point which is a
whole multiple of 20 meters and the next sheet shall start with the
same station.
2.2.11 The profile shall not be drawn closer than 15 cm to the top or 4 cm to
the bottom, of the ruled section of the sheet. Heavy horizontal lines
representing elevations in the profile shall be labeled at each end of
the profile sheet at 4 or 8 meters vertical intervals.
2.2.12 Normally, the plan and profile drawings show the center line survey
profile. In rough terrain where side hills are encountered, actual
profile under the uphill and downhill conductors shall be required to
assure adequate conductor-ground clearances and structure heights.
The engineer responsible for detailed design shall collect all such
information from the field and indicate on the profile drawings.
Existing features to be crossed by the proposed transmission line,
including the height and position of power and communication lines
shall be shown, and noted by station and description in both plan and
profile views. The magnitude and direction of all deflection angles in
the line shall be given and referenced by P.I. station in the plan view.

2.2.13 A legend, identifying conventional symbols used to denote features
on the drawings shall be placed in the starting sheet, however it is
preferable to repeat this legend on every sheet. The legend shall also
identify the center line profile.
2.2.14 Full stations shall be indicated at 200 meters intervals.
2.2.15 The plan shown on the drawing sheet shall consist of either a
photographic view or a topographical view of the proposed
transmission line route. The photographic plan view shall cover 180
meters either side of the center line of the transmission line and be
located on the allocated top portion of the drawing sheet. The photo
plan view shall show centerline of transmission line, structure
locations and beginning and ending stations of the sheet.
2.2.16 The topographical plan view shall be located on the allocated top
portion of the drawing sheet. All topographic features such as
railroads, roads, highways, , rivers, power/pipeline crossings etc. shall
be shown.
2.2.17 A drawing title block shall be placed on every sheet which shall
identify the line, and also include space for recording the personnels
and dates involved in various stages of drawing preparation, line
design, checking, approval and revisions.
2.2.18 Drawings prepared in ink or mylar sheets provide a better permanent
record; however structure spotting initially should be done in pencil
on blue prints and transferred to the mylar sheets after the drawings
are approved and the line is released for construction. The drawings
shall be prepared with the help of computer using CAD system as per
requirements and format specified in SEC Engineering Drawing
Standard SEEDS-II.
2.3 Features of Plan And Profile Drawings
Generally the Plan and Profile drawings include all the necessary information
about the line route such as ground line showing chainage, elevations and
major features traversed. However, for complete and accurate design of a
transmission line certain additional information shall be required. The
engineer responsible for detailed design shall physically traverse the line route
in the field and collect all such information. This information shall include but
not be limited to the following features:
2.3.1 General description of soil type i.e. clay, gravel, rock, sand, sabkha
etc.
2.3.2 Mid-span side slope information in rough terrain which may affect
the ground clearance under the outer phase conductor.

2.3.3 Phase sequence and identification of circuits
2.3.4 Height of the upper most conductors at the point of power line
crossing including ambient temperature.
2.3.5 Roads, railway lines, communication and power lines, pipelines
(being crossed and adjacent) etc. being crossed shall be marked on
both sides of the crossing point along with destination.
2.3.6 Water table depth along the line route to be indicated in the final
design drawings.
2.3.7 Continuous longitudinal chainage including chainage of stretches like
marshy area, water-logged area, compounds and gardens etc. shall be
marked.
2.3.8 Levels shall be taken at every 30 meters along the line route.
However, where there are abrupt change of slope (over 30 cm in
height), cuttings and shallow portions, levels shall also be taken at
these points.
2.3.9 Ground line showing levels.
2.3.10 All structure positions with sketches at angle locations.
2.3.11 Buildings including farm buildings and outhouses, trees and
vegetation.
2.3.12 Areas not suitable for structure locations, areas with difficult access
or foundation problems shall be highlighted.
2.3.13 Areas where shifting sand dunes could affect the conductor ground
clearance and requiring flood protection and traffic embankments.
2.3.14 Areas requiring aviation warning devices such as spherical markers,
phase conductor lights, tower beacon lights and structure painting etc.
2.3.15 Presence of side hills, valleys, wadies, farms, crushers, roads and
median configuration (height and width), utilities in the median and
the street light posts (when the transmission line is to be routed
through the median of the road).
2.3.16 Any other feature which may affect the line design or construction

3.0 SAG TEMPLATE
3.1 General
The sag template is a scaling device used for structure spotting and shows the
vertical position of conductor (and/or ground wire) for specified design
conditions. It is used on plan-profile drawings to determine graphically the
location and height of supporting structures required to meet the line design
criteria for vertical clearances, insulator swing and span limitations. The sag
template permits alternate layout for portions of the line to be investigated and
thereby aids in optimizing line design for economy. Generally, the conductor
sag curves control the line design. The sag template for the overhead ground
wire is used to show its position in relation to the conductors for special spans
or change in conductor configuration.
3.2 Sag Template Curves
The sag template shall include the following sag curves based on the design
ruling span.
3.2.1 Cold Curve
This curve shall indicate initial sag at minimum temperature of -1°C,
no wind and no ice conditions. This shall be used to check for uplift
and insulator swing.
3.2.2 Normal Curve
This curve shall show final sag value of conductor at everyday
temperature at no wind conditions. This shall be used to check
normal clearances and insulator swing. Every day temperature for
various SEC Operating Areas shall be as in Table 07-1 below:
Table 07-1: Every Day Temperature
SEC Operating Area
Every Day
Temperature, o
C
Central 25
Eastern 27
Western 30
Southern 25 & 30
3.2.3 Hot (Maximum Sag) Curve
This curve shall show final sag value at maximum design temperature
at no wind conditions. This shall be used to check for minimum
vertical ground clearances. The maximum design temperature of

conductor producing maximum sag for determining minimum vertical
ground clearances shall be as in Table 07-2 below:
Table 07-2: Maximum Design Temperature
SEC Operating Area
Maximum Design
Temperature, o
C
Central 80
Eastern
85 (ACAR)
93 (ACSR/AW)
Western 80
Southern
85 (AAAC)
93 (ACSR)
3.2.4 Ground Wire Curve
This curve shall indicate final sag value of overhead ground wire at
everyday temperature at no wind and no ice conditions. This shall be
used to check the relative position of ground wire with respect to
conductor’s normal position and mid span clearances in the special
spans or change in conductor configuration.
3.2.5 Ground Clearance Curve
This curve shall indicate the specified ground clearance over open
terrain from the maximum temperature (Hot) curve. This will be
equal to the vertical offset distance below any point on the hot curve.
These curves shall also be used to locate the low points of sags and determine
the vertical (weight) span length of conductors. A sample of typical sag
template indicating all these curves is shown in Figure TE-2207-0100-00. The
intersection of curves with the vertical axis line represents the low point
position of the sag.
3.3 Sag Template Design
3.3.1 For a given conductor, ruling span, design conditions and
temperature, sag values shall be determined using a computer
program. The template shall be made to include spans three or four
times as long as the normal level ground span to allow for spotting
structures on steep terrain. To obtain values for plotting the sag
curves, sag values for the ruling span are extended for shorter and
longer spans than the ruling span. The sag values used for the
template may be calculated with the following formula:

( )S
L
L
S
RS
RS=
⎛
⎝
⎜
⎞
⎠
⎟
2
(Eq. 7-1)
where:
S = Sag of other span in meters
SRS = Sag of the ruling span in meters
L = Length of other span in meters
LRS = Length of ruling span in meters
3.3.2 The template shall be cut to include a minimum of 0.60 meters
additional clearance than the specified to account for possible minor
shifts in structure location and for the errors in plotting the profile.
The sag template drawing shall be made to have the same scales as
the plan and profile sheets and the data required for the preparation
of template shall be per TES-P-122.03 for the specified conductor,
ruling span and loading conditions.
3.3.3 A new template shall be prepared for each line where there is any
variation in voltage, conductor size, loading condition, design tension
or ruling span. A change in any one of these factors may affect the
design characteristics of the template.
3.3.4 In case of steep slopes, where the elevation difference between the
two structure positions is so large that normal sag template cannot be
used, the sag shall be calculated and the sag curves traced
accordingly.
3.4 Sag Template Construction
The sag template shall be made of dimensionally-stable transparent plastic or
celluloid material of about 1mm thickness. A contrasting colored material
such as red may be helpful when the template is used to check Plan & Profile
drawings which are blue prints. The curves are first plotted on paper using
correct scales and then reproduced or copied on the plastic material. To cut a
template, the transparent material is fastened securely over the sheet and the
centerline and upper curves are etched lightly by a sharp-pointed steel scriber.
The outside edges can easily be broken out and the edges sanded smooth.
Structure height scales may also be drawn or etched on the template or a
separate template may be made for determining structure height required for
each type of structure used. The etched lines shall be filled with ink to make
them easier to see when the template is used.
Conductor size, design tension and loading conditions ruling span and
descriptive data for each curve shall be shown on the template.

4.0 STRUCTURE SPOTTING
4.1 General
Structure spotting is the design process which determines the height, location
and type of consecutive structures on the plan and profile sheets. The efficient
location of structures on the profile is an important component of line design.
Structures of appropriate height and strength shall be located to provide
adequate conductor ground clearance and minimum cost. Actual economy and
safety of the transmission line depends on how well this final step in the design
is performed. The structure spotting shall closely conform to the design
criteria established for the line. Constraints on structure locations and other
physical limitations encountered may prevent structure spotting of structures at
optimum locations. Success of the effort to minimize or overcome these
special conditions can be judged by how closely the final line layout follows
the original design parameters.
4.1.1 Structure spotting shall be carried out using manual method or
computer optimization method. In case the later method is used, the
results shall be shown on Plan and Profile drawings and reviewed and
finalized for construction along with structure list.
4.1.2 In the manual structure spotting process, a celluloid/plastic template
shaped to the form of suspended conductor is used to scale the
distance from the conductor to the ground and to adjust structure
locations and heights to provide proper clearance to the ground,
equalize spans and grade the lines.
4.1.3 For a transmission line of significant length (about 100 km or more)
there are a very large number of possible permutations of line layouts
(structure spotting). In the manual method, it is extremely difficult if
not impossible to determine the least cost layout. For such case
computer optimization method shall be required to obtain an efficient
and economical line design.
4.1.4 A well designed and economical layout shall have the following
properties:
a. Spans approximately uniform in length, equal to or slightly less
than the design ruling span. Span utilization factor (defined as
the ratio of average span to the design ruling span) shall be 90%
or more.
b. Maximum use of basic structures of equal height and type. The
basic structure is the height which has been selected as the most
economical structure for the given design conditions.

c. The actual ruling span shall not exceed the design ruling span.
Under exceptional cases (such as single dead-end spans or a
stretch of very short line length between tension towers) longer
or shorter ruling spans shall be acceptable provided there is
enough justification. For such cases new templates shall be
prepared for ruling spans which are more than 20 meters longer
or shorter than the design ruling span and the layout shall be
checked for the new ruling spans.
4.2 Preparation for Structure Spotting
The following data is required for structure spotting on a transmission line:
4.2.1 Plan and Profile Drawings
4.2.2 Sag Template
4.2.3 Table of required minimum conductor clearances over ground
features and other overhead lines in accordance with TES-P-122.09.
4.2.4 Horizontal and vertical span limitations due to clearance and strength
requirements. The maximum and minimum wind span to weight span
ratios shall be established based on maximum allowable swing of
insulators and strength of cross-arms. Procedures for such
calculations are described in References 1 & 2 (Bibliography).
4.2.5 Guy arrangement and anchor requirements for wood pole structures,
procedures for these calculations are also given in References 1 & 2
(Bibliography).
4.2.6 Structure height scale or template. For convenience the structure
scale for each structure may be marked on the margin of the sag
template. Supporting calculations shall be summarized in a chart or
tabular form to facilitate application during structure spotting process.
This is specially advisable for the standard suspension structure
which has a greater range of heights.
4.2.7 The structure height shall not include any margin of foundation reveal
above ground level to achieve the specified minimum ground
clearances. The foundation reveal shall be considered as an extra
margin in clearance for SEC purposes.
4.3 Preliminary Reconnaissance of Plan and Profile
Before actually spotting any structures on the plan and profile sheets, it is
recommended to review the entire line route on the Plan & Profile drawings as
well as in the field and make special note of any unique features that are
encountered.

4.3.1 There may be special features such as line angle points, highway or
railroad crossings, power line or communication line crossings, and
high or low points in the profile which will require special
consideration and affect the location of the structure. Such conditions
often fix the location of structure, and it is usually a matter of
determining the most desirable arrangement of structures between
these fixed locations. In the sections of line where there is a choice of
structure locations, it may be desirable to make more than one layout
in order to determine the best arrangement.
4.3.2 The areas which may be subjected to wind or water erosion shall be
identified. Marshy land, water logged, low lying and rocky areas be
noted and effort should be made to avoid locating structures in these
areas, particularly the angle structures.
4.4 Structure Spotting Procedure
The process of spotting shall begin at a known or established conductor
attachment point such as a substation take-off structure or point of intersection
(P.I.) and usually progresses from left to right on the profile. The sag template
is held vertically and ground clearance curve is held tangent to the profile.
After the structure at the starting point is established and height is selected, the
next structure height and location is determined either by scaling or by use of
structure template.
4.4.1 The template shall then be shifted and adjusted so that with the
opposite edge of the template held on the conductor attachment point
previously located with the clearance curve again barely touching the
profile. The process is repeated to establish the location of each
succeeding structure.
4.4.2 The above procedure can be followed only on lines that are
approximately straight and which cross relatively flat terrain with the
basic ground clearances. When line angles, broken lines and
crossings are encountered, it may be necessary to try several different
arrangements of structure locations and heights at increased
clearances to determine the arrangement that is most satisfactory.
4.4.3 The relationships of the ground clearance and conductor curves is
also used for spans other than level-ground spans by shifting the sag
template until ground profile touches or is below the clearance curve
with the previously established conductor attachment point (normally,
the left) positioned on the conductor curve. The conductor curve will
then indicate the required conductor height for any selected span.

4.5 Crossings
For spans crossing features such as highway or railroads and powerline or
communication lines will require different clearance requirements than the
normal clearance.
4.5.1 Minimum vertical clearances per TES-P-122.09 shall be maintained
over all such crossings under a broken conductor condition in either
of the spans adjacent to the crossing span.
4.5.2 The increase in sag due to a broken conductor in adjacent span is
usually significant only where suspension-type structures are used at
crossing.
4.6 Insulator Sideswing
Suspension insulators are subjected to sideswing caused by horizontal wind
pressure. Conductor clearance to the structure is reduced by insulator
sideswing, so it is necessary to limit the sideswing in order to maintain proper
conductor insulation. Suspension insulators also deflect laterally at line angle
locations due to the transverse component of conductor tension. The
horizontal force that tends to swing an insulator string suspended on a structure
is equal to one-half (1/2) the total wind pressure on the conductors in the two
adjacent spans. The vertical force that tends to keep the insulator string from
swinging is equal to the weight of the conductor supported by the insulator
string plus one-half (1/2) the weight of the insulator string. The length of
conductor supported by the insulator string is equal to the distance between the
conductor low points of the adjacent spans, which is called vertical or weight
span.
4.6.1 On rough terrain where each of the adjacent spans fall rapidly away
from the structure, the conductor low points, as indicated by the sag
template, may fall on the adjacent spans. However, the distance
between the low point is still the length of conductor to be considered
as acting vertically to hold the insulator from swinging. Excessive
low-point distance can cause a failure in the insulators, hardware or
the structure.
4.6.2 For such cases, the wind span to weight span ratio shall be calculated
and checked against the minimum and maximum allowable limits. In
case it is beyond the allowable limits, following corrective steps are
recommended in order of preference.
- Relocate structures to adjust wind to weight span ratio
- Increase structure height or lower adjacent structures
- Use of a different structure, one with greater allowable swing
angle or a dead-end structure

- Add weight at insulators to provide the required additional
vertical force.
4.7 Grading and Uplift
The most desirable layout is to have spans of nearly uniform length that are
equal to or slightly less than the ruling span, a smooth conductor profile, and
structure of equal heights. The smooth conductor profile is a sign of good
design. The conductor attachment points at each of the structure shall lie in a
smooth flowing curve to equalize structure loading, as much as possible. This
is called grading the line and is an important part of the design of a
transmission line.
4.7.1 Uplift is defined as negative weight span and is determined by the
same procedure as weight span. This condition shall be avoided if
possible. Uplift may occur in a rough profile where the conductor
supports are at different elevations. For example, refer to the three
structures on Figure TE-2207-0200-00. The conductor sag is drawn
at an every day temperature, but as the temperature decreases, the
conductor will contract and the sag will decrease. When the
temperature reaches the minimum value, the conductor assumes the
position indicated by the cold curve shown on the template.
Therefore, by placing the curve on the template between the
conductor supports of alternate structures, it can be determined
whether the conductor support of the intermediate structure is above
or below the cold curve. If the conductor support would then be
below the cold curve, the conductor would exert an upward pull on
the structure and this upward pull is the Uplift. Uplift at a structure
will cause the conductor to pull the suspension insulators up into the
crossarm and with the horizontal post insulators, it might cause the
conductor to pull away from the insulator. Uplift may possibly be
avoided by adjusting structure locations in the profile drawings, to
take advantage of the terrain and by using a higher structure at the
point of uplift.
4.7.2 If these methods fail, then the conductor must be dead-ended.
Designing for uplift or minimizing its effects is similar to the
corrective measures for excessive insulator swing, except that adding
of excessive weight shall be avoided. Double dead-ends and certain
angle structure can have uplift as long as the total force of uplift does
not approach the structure weight. If it does, hold down guys are
necessary, if applicable.
4.8 Dead-ending
In transmission lines that contain long stretches of flexible or semi-flexible
tangent structures between dead-ends, it is possible for longitudinal loads, such
as high longitudinal winds or broken conductors, to cause cascading failures.
To reduce the tendency to cascade and to control the extent of cascading

failures, in-line dead-end structures shall be used at an intervals not exceeding
5 kilometers for wood structures and 12 kilometers for steel structures. These
in-line dead-end structures shall be designed to resist the full maximum tension
of all conductors and overhead ground wires in either span adjacent to the
structure, as if the other span tensions were interrupted.
4.8.1 When it is necessary to use spans longer than approximately 1.7 times
the ruling span or shorter than one-half (1/2) the ruling span, the
conductors shall be dead-ended at both ends of the span and sagged to
a special ruling span. River or water crossings involving special
structures or long spans are to be handled as special studies.
4.8.2 The maximum tension in conductors and overhead ground wires
under full load condition shall be reduced approximately 50 percent
in the slack span terminating on the substation or switchyard
structure. Anchor structures shall be installed adjacent to the
substation or switchyard and when spanning major highways.
4.8.3 The deflection angle in the transmission line at the substation or
switchyard structure shall not be more than ten degrees (10°) because
a larger deflection angle reduces the clearance and imposes additional
transverse load on the substation structure.
4.9 Structure Numbering
After the location of the structures have been established, each structure is
assigned a structure number. The structure numbers are assigned
consecutively, regardless of structure type, in the direction of increasing
stationing. The structure number is shown on the Plan and Profile drawings,
and the same number shall be permanently applied to the structure in the field.
4.9.1 On all radial feeders and tap lines, the structure numbering shall begin
at the line origin and will increase toward line destination. The line
name designation will be determined by the destination of the line
rather than the name of the main line.
4.9.2 On other transmission lines, the structure numbering shall begin with
structure one from south to north or west to east. This geographical
direction is dependent on the location from substation to substation
and not to the direction of the line at any point. The line name
designation shall be according to the station name at each end of the
line with the first name listed dependent on the same geographical
directions listed above; i.e., the Abqaiq-Qurayyah line will be
designated by AB-QU.

4.10 Other Considerations
If maximum conductor tension or other limits are not exceeded, it may be
preferable to use one long span with adequate conductor separation over a
depression in the profile rather than use two short spans with a dead-end
structure at the bottom of the depression which may be subjected to
considerable uplift at minimum conductor temperature. Care must be
exercised at locations where the profile falls sharply away from the structure to
check that the maximum allowable weight span as limited by the strength of
the cross-arm or insulator is not exceeded.
4.10.1 For long span it may be necessary to check sidehill clearance with
conductors in their maximum transverse swing position.
4.10.2 Structures with adequate longitudinal strength shall be required at
locations where longitudinal loading results from unequal line
tensions in adjacent spans.
4.10.3 Structures shall be so located that risk of the foundation damages by
floods, shifting sands or other phenomenon is minimized. In areas of
shifting sand dunes, extra ground clearance per TES-P-122.09 shall
be allowed where necessary, in order to ensure that movement of the
sand dunes will not reduce conductor clearance over ground below
the specified minimum.
4.11 Drawing Check and Review
The completed plan profile drawings shall be checked to insure that the line
meets the design requirements and criteria originally specified, adequate
clearances and computed limitations have been maintained. The drawings
shall be checked for completeness, accuracy and clarity. All structure locations
shall be verified in the field to check their suitability in view of foundations or
any other requirement. The final drawings shall be thoroughly checked to
ensure that wind and weight spans are within permissible limits and lateral
clearance to road, railway lines, pipelines and canal edges are as specified.
4.12 Structure List
After completion of structure spotting and review of plan & profile drawings
based on field checks, a schedule of transmission line structures i.e. Structure
List shall be prepared. The structure list shall include, but not be limited to the
following information:
4.12.1 Station levels and point of intersections.
4.12.2 Structure numbers along with ahead span, wind span, weight span and
ruling span etc.

4.12.3 Structure types, conductor attachment heights height of extension,
type of footing, deflection angle etc.
4.12.4 Number and spacing of vibration/spacer dampers, spherical markers
& warning lights/beacon lights, structure footing resistance &
grounding and type of insulator assemblies etc.
4.12.5 Features to be crossed by transmission line such as power/
communication lines, pipe lines, railroad, roads/highways, canals etc.
4.12.6 Coordinates of P.I stations.
4.12.7 Structure painting (if required), foundation reveal and soil type.
4.12.8 Specifications of conductor, overhead ground wire and OPGW and
controlling conditions used in the sag-tension data.
5.0 BIBLIOGRAPHY
5.1. Design Manual for High Voltage Transmission Lines, REA Bulletin 62-1, U.S.
Department of Agriculture.
5.2. Transmission Line Design Manual, U.S. Department of the Interior, by
Holland H. Farr.

Tes p-122.07-r0

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