TRANSMISSION ENGINEERING STANDARD
TES-P-122.09, Rev. 0
TABLE OF CONTENTS
1.0
SCOPE
2.0
LINE ROUTES
2.1
2.2
2.3
2.4
3.0
Location
Paralleling and Crossing Transmission Lines
Paralleling and Crossing Major Highways
Vertical Clearances above Ground, Road Crossings and Paralleling, Crossing of Rail
Road
GENERAL GUIDE LINES FOR METALLIC FACILITIES LOCATED IN PROXIMITY
OF TRANSMISSION LINES ( INDUCED / CONDUCTIVE VOLTAGE
INTERFERENCES)
3.1
3.2
3.3
Inductive & Conductive Voltage Requirements
Paralleling Facility (Induced Voltage Case)
Crossing Facility (Conductive Voltage Case)
4.0
SPACING FROM MAIN OIL FACILITIES
5.0
CONDUCTOR SPACING AND CLEARANCE
5.1
5.2
5.3
5.4
5.5
5.6
5.7
5.8
Clearance between Phase Conductors on the same Support
Vertical Clearance between Line Conductors.
Clearance of Conductor from its own Support - Basic Clearance.
Clearance between Phase Conductors carried on different Supports
Clearance of Conductors from other supporting Structures
Clearance of Conductors from other Installations
Midspan Clearance
Air Gap Requirements
TESP12209R0/MAA
Date of Approval: December 12, 2007
PAGE NO. 2 OF 39
TRANSMISSION ENGINEERING STANDARD
6.0
RIGHT-OF-WAY WIDTH REQUIREMENTS
6.1
6.2
6.3
6.4
6.5
7.0
TES-P-122.09, Rev. 0
General
Conductor Clearance to edge of Right-of-Way
Right-of-Way Width Requirements for Single Transmission Line
Right-of-Way Width Requirements for Parallel Transmission Lines
Example Calculation of Right-Of-Way
BIBLIOGRAPHY
FIGURE TE-2209-0100-00 Clearance Requirement for Conductors of Same Circuit or Different
Circuit on the Same Support
FIGURE TE-2209-0200-00 Clearance Requirement for Conductors from other Circuits and
Right-Of-Way (ROW) for Single Transmission Line
FIGURE TE-2209-0300-00 Clearance Requirement between Conductors on Different Supports
and Conductors from other Supporting Structures and Right-Of-Way
(ROW) for Two Parallel Transmission Lines
FIGURE TE-2209-0400-00 Right-Of-Way (ROW) Requirement for Two Parallel Transmission
Lines
TESP12209R0/MAA
Date of Approval: December 12, 2007
PAGE NO. 3 OF 39
TRANSMISSION ENGINEERING STANDARD
1.0
TES-P-122.09, Rev. 0
SCOPE
The purpose of this standard is to highlight Saudi Electricity Company (SEC), Saudi Arabia
practices with respect to clearances required for various paralleling and crossing facilities
and right of way requirements.
2.0
LINE ROUTES
2.1
2.2
2.3
Location
2.1.1
Transmission lines shall be located as near as possible to roads for easy
accessibility during construction and later for inspection, insulator
washing, maintenance and repair. Obstacles such as high hills, wadis,
water flooding areas, swampy ground or poor soils shall be avoided.
Selection of routes shall also take into account grade and conditions of the
terrain to be traversed.
2.1.2
Selection of final route for any transmission line shall be coordinated with
the concerned SEC departments.
2.1.3
Coastal or corrosive atmosphere areas shall be avoided wherever possible.
Whenever it is not possible suitable protective measures shall be adopted in
the design of transmission line components including foundations to
combat the corrosion.
Paralleling and Crossing Transmission Lines
2.2.1
Adequate clearance shall be provided between parallel and crossing
transmission lines. Clearances between adjacent conductors of two parallel
lines and clearances between crossing lines shall be established per
equations 09-1 to 09-19.
2.2.2
Crossing lines shall be arranged so that the higher voltage line or line of
higher security crosses over the line of lower voltage or lower security. It is
preferable that transmission lines shall cross each other at right angles.
2.2.3
The vertical clearance between any crossing lines carried on different
supporting structures shall not be less than those given in Table 09-13.
Paralleling and Crossing Major Highways
2.3.1
TESP12209R0/MAA
Major highways are defined as any primary or secondary roads which are
normally accessible to traffic with no restriction. Minimum clearances
from the nearest conductor to edge of major highways for restricted and
unrestricted rights of way are given in Table 09-1.
Date of Approval: December 12, 2007
PAGE NO. 4 OF 39
TRANSMISSION ENGINEERING STANDARD
TES-P-122.09, Rev. 0
Table 09-1: Minimum Distance from nearest Conductor to edge of Major Highways
Voltage, (kV)
69
110
115
132
230
380
2.4
Right of Way Not-Restricted, (m)
Maximum Height of
Transmission Line Structure
Plus 5 meters
Right of Way Restricted, (m)
18
25
25
25
30
40
2.3.2
Where transmission line routes cross major highways, the angle of
intersection shall be as near as possible to 90 degrees and if not possible,
the angle of intersection shall be between 45 to 135 degrees. The edge of
the nearest transmission line structure foundation shall not be closer than a
distance equal to the maximum height of the structure installed when
measured from the edge of zone of major highways.
2.3.3
When paralleling roads other than major highways, especially roads in
urban areas, lesser clearances than required by paragraph 2.3.1 are
permissible between roads and transmission lines provided that public
safety and safety & reliability of the lines are not affected. When
necessary, the line structures shall be protected by providing crash barriers
around them without jeopardizing access to the line for maintenance. These
protective measures shall be considered individually on a project basis for
their effectiveness.
Vertical Clearances above Ground and Road Crossings and Paralleling, Crossing of
Rail Road
2.4.1
Vertical clearance is defined as the vertical distance between the highest
point on terrain (grade, road surface, rail road, rail etc.) and the lowest
conductor of the overhead lines. Calculation of actual line clearance at
final tension shall be based on a temperature of 80°C for ACSR & AAAC,
85°C for ACAR and 93°C for ACSR/AW conductor. Grading of existing
natural ground level to meet the vertical clearance requirements shall not
be acceptable unless otherwise approved by SEC.
2.4.2
The minimum vertical clearances required for SEC transmission line
designs for 380 kV and below over various types of roads and terrain are
given in Table 09-2 and shall be followed unless otherwise specified in the
approval letters of different approval agencies involved.
2.4.3
Roads to be crossed by SEC transmission lines have been categorized as
“A”, designated high clearance roads; and “B”, for other roads not
requiring high clearance.
2.4.4
There are some areas where certain road crossings shall require additional
clearance. The extra high clearance roads in the industrial areas such as
Jubail, Dammam, Yanbu, etc. may require a vertical clearance in the range
of 18-21 meters above roads or highways.
TESP12209R0/MAA
Date of Approval: December 12, 2007
PAGE NO. 5 OF 39
TRANSMISSION ENGINEERING STANDARD
TES-P-122.09, Rev. 0
2.4.5
The category of roads to be crossed by the transmission line shall be
determined during base design stage and in case of module paths the
concerned authorities shall be contacted to coordinate the vertical clearance
requirements.
2.4.6
Highways and roads designated to be used for hauling heavy and oversized
loads are classified as Category ‘A’. All other roads, highways and
expressways are classified Category ‘B’.
2.4.7
On projects where the transmission line is determined to be extremely
important (such as 230 kV and 380 kV System) and power interruption can
not be tolerated, then all roads to be crossed by this line shall be considered
as Category “A” roads, and the Project Scope of Work and Technical
Specifications for such a project shall explicitly state this requirement.
2.4.8
The road clearances in this Standard for designated high clearance roads
and expressways and highways considerably exceed the minimum
requirements recommended by the NESC for vertical clearances above
roadways.
2.4.9
The vertical clearances over the type of terrain not covered by Table 09-2,
such as canals, waterways, terrain in the vicinity of airports or any unusual
situation which might be developed, shall be resolved separately and
mutually agreed to by interested parties.
Table 09-2: Minimum Vertical Clearances for Roads and Terrain Crossings (see note 5)
Transmission Voltage (Line to Line)
Category
A.
B.
C.
D.
Type of Crossing
Designated
High
Clearance Roads (1)
Expressways
&
Highways
City Streets, Alleys
Driveways, Parking
Lots & Other Areas
Traversed
by
Vehicles, Paved or
Unpaved
Open Terrain, Desert
Areas, etc (3, 4).
69kV
(m)
110kV
(m)
115kV
(m)
132kV
(m)
230kV
(m)
380kV
(m)
14.0
14.0
14.0
15.0
18.0
18.0
12.0
12.0
12.0
13.0
15.0
15.0
12.0
12.0
12.0
13.0
15.0
15.0
7.5
7.5
7.5
7.5
8.0
10.0
E.
Railroads (2)
15.5
15.5
15.5
16.0
18.0
18.0
F.
Ground
Facilities,
Pipelines (Oil, Water,
Gas)
&
Communication lines
9.5
9.5
9.5
9.5
9.5
13.5
Notes:
1.
TESP12209R0/MAA
Roads categorized as “A” are those specifically designated by SEC Lines Maintenance
Department as roads requiring vertical clearance in excess of clearances listed in Category
Date of Approval: December 12, 2007
PAGE NO. 6 OF 39
TRANSMISSION ENGINEERING STANDARD
TES-P-122.09, Rev. 0
“B” and “C”. Vehicle traffic is expected to exceed 5.5 meter height and the transmission
lines need not normally be removed from service.
2.
Assumed height of the rail car is 6 meters.
3.
For transmission lines when located in open terrain within 5km and 2km from the
boundary limits of cities/towns and villages respectively, the required clearances listed
under Category “D” shall be increased by a minimum of two (2) meters.
4.
When transmission lines are located in desert area affected by shifting sand dunes, the
clearance listed in Category “D” shall be increased by a minimum of two (2) meters in the
spans indicating shifting sand dunes.
5.
The clearances shall be increased @ 3 % for each 300m in excess of 1,000m altitude
above mean sea level.
2.4.10
Paralleling and Crossing Railroads
a.
Minimum clearances from the nearest conductor to edge of the
rail track for restricted and unrestricted rights of way are given
Table 09-3.
b.
Where transmission line routes cross railroad tracks, the angle of
intersection shall preferably be 90 degrees and if not possible, the
angle of intersection shall be between 70 to 110 degrees. The edge of
the transmission line structure foundation shall not be closer than 50
meters on 69kV through 380kV transmission lines to the edge of the
railroad track.
Whenever the required crossing angle is not satisfied, the Engineer
responsible for base design/detailed engineering shall perform an
induced voltage study and recommend possible steps to be taken to
reduce any adverse effects.
c.
The minimum vertical clearances required for SEC transmission
lines for 69 kV to 380kV, over the railroad tracks are given in
Table 09-2.
Table 09-3: Minimum Clearances for Paralleling of Railroad
Voltages, (kV)
69
110
115
132
230
380
TESP12209R0/MAA
Right-of-Way
Unrestricted, (m)
Restricted, (m)
40
25
40
25
40
25
40
25
40
30
40
40
Date of Approval: December 12, 2007
PAGE NO. 7 OF 39
TRANSMISSION ENGINEERING STANDARD
3.0
TES-P-122.09, Rev. 0
GENERAL GUIDELINES FOR METALLIC FACILITIES LOCATED IN PROXIMITY
OF
TRANSMISSION
LINES
(INDUCED/CONDUCTIVE
VOLTAGE
INTERFERENCES)
3.1
Inductive and Conductive Voltage Requirements.
The guidelines listed below shall be followed for all the requests of customer
metallic facilities, such as pipelines, rail road, communication cables, cathodic
protection systems, etc., (whether overhead, above-ground or under-ground) to cross
and/or run in close proximity to SEC transmission lines. The following guidelines
shall be applied to all facilities in a single location in case more than one facility is
involved in the request.
3.1.1
3.1.2
SEC approval for allowing other parties to construct and install their
projects in parallel to and/or crossing the transmission lines shall be
granted if the project proponent satisfy all the following conditions:
a.
Accepts full liability and any consequential damages due to the
electrical interference (induced/conductive voltage) effects and
satisfies conditions given in Clause 3.3.1 and 3.3.2 below (for
crossing only).
b.
Performs at his expense induced/conductive voltage study and
proves to SEC’s satisfaction that the resulting touch voltages are
within the limits specified in Clause 3.1.2 and 3.1.3 below and
satisfies the conditions given in Clause 3.3.1 and 3.3.2 below (for
crossing only).
c.
Satisfies the requirements specified in Clause 3.2 and 3.3.
The maximum touch voltage limit to insure safety to personnel during
steady-state conditions shall be as follows:
Conditions
Continuous Voltage
Continuous Current
3.1.3
Limits
15 volts
10 milli-amperes
The maximum touch voltage limit to insure safety to personnel during fault
conditions shall be according to the following ANSI/IEEE 80 equation:
Vtouch =
116 + (017
. ρ)
t
Where:
ρ = Surface soil resistivity in ohms-meters
t = Fault duration in seconds. This shall be taken as 0.5 seconds or backup
clearing time whichever is higher.
TESP12209R0/MAA
Date of Approval: December 12, 2007
PAGE NO. 8 OF 39
TRANSMISSION ENGINEERING STANDARD
TES-P-122.09, Rev. 0
Therefore, for 500 ohm-meter top soil resistivity and 0.5 second fault
clearing time, the safe touch voltage limit is 284 volts.
3.1.4
3.2
If the proponent’s induced/conductive voltage study show the need to
install mitigation to limit the touch voltage, Transmission Asset Planning
Department (TAPD) shall review the case to determine that the appropriate
procedures are followed.
Paralleling Facility (Induced Voltage Case)
When the rights of ways are unrestricted following minimum spacing between the
centerlines of transmission lines and above grade or below grade metallic facility
shall be maintained. In case the minimum distances cannot be maintained the
request shall be referred to TAPD for review.
Table 09-4: Clearances for Induced Voltage for Metallic Facility
Voltage Level
69kV to 132kV
230kV and 380kV
3.3
Clearance, (m)
150
300
Crossing Facility (Conductive Voltage Case)
3.3.1
The minimum vertical clearance between the transmission lines and ground
facilities shall be per Table 09-2.
3.3.2
When ground facilities cross transmission line access roads, the facility
crossing shall be designed to provide safe passage of vehicular traffic. For
unpaved crossing of above grade facility, refer TES-P-122.11.
3.3.3
When the facility routes cross overhead transmission line the preferred
angle of intersection is 90 degrees and if not possible crossing angle
between 70 to 110 degrees shall be acceptable.
3.3.4
The facility shall cross the transmission line at mid span between towers,
otherwise the crossing shall be minimum 100 meters away from the nearest
transmission line foundation for 230 kV and 380 kV transmission lines and
minimum 50 meters away from the nearest transmission line foundation for
69kV, 110kV, 115kV and 132kV transmission lines.
3.3.5
If the facility runs parallel to the transmission line after the intersection
then it shall also meet minimum distance requirements mentioned under
clause 3.2 above. If the metallic facility is crossing below the grade and
changing its direction at a distance less than 300 meters (for 230kV and
380kV transmission lines) and 150 meters (for 69kV, 110kV, 115kV and
132kV transmission lines) from crossing, the facility shall be grounded at
the point where the direction is changing.
TESP12209R0/MAA
Date of Approval: December 12, 2007
PAGE NO. 9 OF 39
TRANSMISSION ENGINEERING STANDARD
TES-P-122.09, Rev. 0
If the metallic facility is crossing above the grade, the facility shall be
grounded up to 100 meters along the length of the facility in both
directions from the crossing point. If the facility is changing its direction at
a distance greater than 100 meters and less than 300 meters (for 230kV and
380kV transmission lines) and 150 meters (for 69kV, 110kV, 115kV and
132kV transmission lines) from the crossing point, additional grounding
shall be provided at the point where the direction is changing. The
grounding of the metallic facility shall be to the satisfaction of the
concerned party.
4.0
SPACING FROM MAIN OIL FACILITIES
Horizontal spacing between the edge of the foundation of the transmission lines and edge of
the main oil facilities shall be provided for safe operation and maintenance of both.
Minimum spacing for 69 kV to 380 kV transmission lines to main oil facilities shall be as
follows:
Table 09-5 Minimum Spacing for Oil Facilities
Oil Facility Type
Oil Wells and GOSPs
Oil Trunk
Ground Flares and Burn Pits
Elevated Flare Stacks
Oil-Water Separators and Skimming Ponds
Other Oil Process Areas
5.0
Spacing, (m)
200
150
150
60
60
60
CONDUCTOR SPACING AND CLEARANCE
5.1
Horizontal Clearance between Phase Conductors on the same Support
5.1.1
Horizontal Clearance - Fixed Support
Phase conductors attached to fixed supports shall have horizontal
clearances from each other not less than the larger value required by
equations given below:
a.
Phase Conductors of the Same Circuit
i.
ii.
b.
(Eq.09-1)
(Eq.09-2)
Phase Conductors of Different Circuits
i.
ii.
TESP12209R0/MAA
H = 300+10 (U-8.7)
F = 7.6 (U)+8 2.12 S
H = 725+10 (Uo-50)
F = 7.6 (Uo)+ 8 2.12 S
Date of Approval: December 12, 2007
(Eq.09-3)
(Eq.09-4)
PAGE NO. 10 OF 39
TRANSMISSION ENGINEERING STANDARD
TES-P-122.09, Rev. 0
Where:
H = Basic horizontal clearance between phase conductors in mm.
F = The horizontal clearance due to sag between phase conductors in
mm.
U = The maximum operating voltage phase to phase over 8.7 kV
Uo= Maximum operating voltage between line conductors of different
circuits which shall be the greater of the phasor difference
between the conductor involved, or the phase-to-ground voltage
of the higher voltage circuit. For circuits having the same phases
and nominal voltage, either circuit may be considered to be the
higher voltage circuit.
S = Final unloaded sag based on computed ruling span at every day
conductor temperature, no wind, in mm.
A margin of 0.6m shall be added to the claculated values to account
for design errors.
The clearances shall be increased @ 3 % for each 300m in excess of
1,000m altitude above mean sea level.
5.1.2
Horizontal Clearance - Suspension Insulators
Where suspension insulators are used and are not restrained from
movement, the clearance shall be increased so that one string of insulators
may swing transversely through a range of insulator swing up to its
maximum design swing angle without reducing the values given in
equations 09-1 to 09-4 and 09-11 to 09-16. The maximum design swing
angle shall be based on 1064 N/m2 wind on the insulator.
a.
The insulator swing shall be calculated as follows:
For maximum angle of swing:
⎡ 2T Sin (θ/2 ) + (HS x Pc ) ⎤
φ = Arc Tan ⎢
⎥
⎣ (VS x W c ) + Wi /2 ⎦
(Eq.09-5)
For minimum angle of swing:
⎡ 2T Sin (θ / 2) − ( HS x Pc ) ⎤
φ = Arc Tan ⎢
⎥
⎣ ( VS x Wc ) + Wi / 2 ⎦
Where
(Eq.09-6)
φ = angle with the vertical through which the insulator string swings
TESP12209R0/MAA
Date of Approval: December 12, 2007
PAGE NO. 11 OF 39
TRANSMISSION ENGINEERING STANDARD
TES-P-122.09, Rev. 0
θ = line angle in degrees
T = conductor tension at the temperature and wind loading for which
the clearance is specified, in Newtons
HS = horizontal span, which is 1/2 the sum of adjacent spans, in
meters
VS = vertical span, which is the distance between the low point of
sag in adjacent spans, in meters
Pc = wind load per unit length of conductor (conductor diameter times
wind pressure), in Newtons/meter
Wc = weight per unit length of bare conductor, in Newtons/meter
Wi = weight of insulator string divided by number of conductors per
phase, in Newtons
b.
The horizontal swing of insulators can be obtained from the equation:
B = (Insulator assembly length) Sin φ
Where: φ is the maximum swing angle calculated per equation 09-5.
5.1.3
Horizontal Clearance for different Circuits where one or both Circuits
exceed 98kV Phase-to-Ground
a.
The clearances specified in equations 09-1 to 09-4 and equations 09-5
and 09-6 may be reduced for circuits with known switching surge
factors shall not be less than the clearances derived from the equation
below:
1.667
⎡ U (SSF) a ⎤
Min. clearance (H) = 1000⎢ L − L
⎥⎦
500k
⎣
Where:
×b
(Eq.09-7)
UL-L = Maximum alternating current crest operating voltage between
phases of different circuits. If the voltages are of the same
phasor and magnitude, one phase conductor shall be
considered grounded.
SSF = Maximum switching surge factor expressed in per unit peak
operating voltage between phases of different circuit. (SSF
value shall be obtained from Transmission Asset Planning
Department).
a = 1.15, the allowance for three standard deviations
TESP12209R0/MAA
Date of Approval: December 12, 2007
PAGE NO. 12 OF 39
TRANSMISSION ENGINEERING STANDARD
TES-P-122.09, Rev. 0
b = 1.03, the allowance for nonstandard atmospheric conditions.
k = 1.4, the configuration factor for a conductor-to-conductor gap
The clearance shall be increased @ 3 % for each 300m in excess of
450m above mean sea level.
b.
5.1.4
5.2
The clearance derived from above equation shall not be less than the
basic clearance given in equations 09-1 to 09-4.
The method on how to determine the horizontal clearance between
conductors of the same or different circuits on the same support is shown
in Figure TE-2209-0100-00.
Vertical Clearance between Line Conductors
All conductors located at different levels on the same supporting structure of the
same or different circuits for the same sag, shall have vertical clearances not less
than required by the equations given below:
5.2.1
For Phases of the same Circuit
a.
Vs = 830+10 (U-50)
(Eq.09-8)
Where:
Vs = Basic vertical clearance phase-to-phase, in mm
U = Maximum operating voltage phase-to-phase, over 50 kV
b.
Minimum vertical clearances calculated based on the above equation
are tabulated below:
Table 09-6: Vertical Clearances between Line Conductors for same
Circuit on the same Structure
Nominal Voltage, (kV)
69
110
115
132
230
380
Vertical Clearance between Phases of the
same Circuit on the same Structure, (m)
1.10
1.60
1.60
1.80
2.90
4.60
Notes:
1.
A margin of 0.15m shall be added to account for design errors.
TESP12209R0/MAA
2.
The clearances at the supporting structures shall be increased to
compensate the reduction in span clearances caused by jumping of
conductors in the longer spans.
3.
The clearances shall be increased @ 3 % for each 300m in excess of
1,000m altitude above mean sea level.
Date of Approval: December 12, 2007
PAGE NO. 13 OF 39
TRANSMISSION ENGINEERING STANDARD
5.2.2
TES-P-122.09, Rev. 0
For different Circuits on the same Structure of different Nominal Voltage
a.
Vc = 830+10[(U01+U02)-50]
(Eq.09-9)
Where:
Vc = Basic vertical clearance between circuits in mm
U01 = Maximum phase-to-ground voltage of circuit at upper level,
over 50 kV
U02 = Maximum phase to ground voltage of circuit at lower level,
over 50 kV
When the circuits have the same nominal voltage, either circuit may
be considered to be the higher voltage circuit.
b.
Minimum vertical clearances were calculated based on the above
equation and tabulated below:
Table 09-7: Vertical Clearance between different Circuits on the
same Structure for different Voltages
Nominal Circuit Voltages, (kV)
69/69
110/110
115/115
132/132
230/230
380/380
Vertical Clearance between different
Circuits on the same structure of different
Nominal Voltages, (m)
1.20
1.75
1.80
2.0
3.25
5.15
Notes:
1.
A margin of 0.15m shall be added to account for design errors.
5.2.3
2.
The clearances at the supporting structure shall be so adjusted that the
clearances at any point in the span shall not be less than the values given
in the table when measured with upper conductor at final unloaded sag at
the maximum temperature for which the conductor is designed to operate
and the lower conductor at final unloaded sag under the same ambient
conditions and without electrical loading.
3.
The clearances shall be increased @ 3 % for each 300m in excess of
1,000m altitude above mean sea level.
Clearances for different Circuits where one or both exceed 98kV to Ground
The clearances specified in equations 09-8 and 09-9 may be reduced for
circuits with known switching surge factors, but shall not be less than the
clearances required by the equation below:
TESP12209R0/MAA
Date of Approval: December 12, 2007
PAGE NO. 14 OF 39
TRANSMISSION ENGINEERING STANDARD
TES-P-122.09, Rev. 0
⎡ ( U (SSF) + U L ) a ⎤
Min. Clearance (V) = 1000⎢ H
⎥
500k
⎣
⎦
Where:
1.667
× bc (Eq.09-10)
UH = Higher voltage circuit maximum crest operating voltage to ground
UL = Lower voltage circuit maximum crest operating voltage to ground
SSF = Higher voltage circuit maximum switching surge factor expressed in
per-unit peak voltage to ground. (SSF value shall be obtained from
Transmission Asset Planning Department).
a = 1.15, the allowance for three standard deviations
b = 1.03, the allowance for nonstandard atmospheric conditions.
c = 1.2, the margin safety
k = 1.4, the configuration factor for conductor-to-conductor gap
The clearance shall be increased @ 3 % for each 300m in excess of 450m
above mean sea level.
5.3
Clearance of Conductor from its own Support - Basic Clearance
5.3.1
Clearance in any direction from a line conductor to the surface of its own
support structure shall not be less than that calculated by the following
equation:
Clearance ‘T’ = 330mm+5mm (U-50)
(Eq.09-11)
Where, U = Maximum operating voltage phase-to-phase, over 50kV
Minimum clearances of phase conductor to its own supporting structure
were calculated based on the above equation and tabulated below:
Table 09-8: Clearance of Phase Conductor to its own Support
Nominal Voltage, (kV)
69
110
115
132
230
380
Clearance of Phase Conductor to
its own Support Arm and Structure, (m)
No Wind Condition
Maximum Wind Condition
0.69
0.50
1.30
0.70
1.30
0.75
1.50
0.80
2.1
1.35
3.50
2.20
Notes:
1.
A margin of 0.15m shall be added to account for design errors.
TESP12209R0/MAA
Date of Approval: December 12, 2007
PAGE NO. 15 OF 39
TRANSMISSION ENGINEERING STANDARD
5.3.2
TES-P-122.09, Rev. 0
2.
The clearances (maximum wind) given in the above table shall be maintained when
the insulator strings and conductors swing transversely upto maximum design
swing angle.
3.
The clearances shall be increased @ 3 % for each 300m in excess of 1,000m
altitude above mean sea level.
Clearances of Conductor from its own Support-Alternate Clearances for
Voltages exceeding 98kV Phase to Ground
The clearances specified in Eq.09-11 may be reduced for circuits with
known switching surge factor but shall not be less than the clearances
derived from the equation shown below:
1.667
⎡ U (SSF) a ⎤
Min. Clearance (T) = 1000⎢ L-G
⎥⎦
500k
⎣
Where:
×b
(Eq.09-12)
UL-G = Maximum alternating current crest operating voltage to ground;
SSF = Maximum switching surge factor expressed in per-unit peak voltage
to ground
a = 1.15, the allowance for three standard deviations with fixed insulator
supports
a = 1.05, the allowance for one standard deviation with free swinging
insulators
b = 1.03, the allowance for nonstandard atmospheric conditions;
k = 1.2, the configuration factor for conductor-to-tower window.
The clearance shall be increased @ 3 % for each 300m in excess of 450m
above mean sea level.
5.3.3
TESP12209R0/MAA
When suspension insulators are used and are not restrained for movement,
the clearance shall be increased so that the insulator strings may swing up
to maximum design angle without reducing the values as tabulated in Table
09-8. The maximum insulator swing angle shall be determined as outlined
in equation 09-5.
Date of Approval: December 12, 2007
PAGE NO. 16 OF 39
TRANSMISSION ENGINEERING STANDARD
5.4
TES-P-122.09, Rev. 0
Clearance between Phase Conductors carried on different Supports
5.4.1
Horizontal Clearance between Conductors
a.
Basic Clearance
The horizontal clearance between adjacent conductors carried out on
different supporting structures shall not be less than required by the
equation below:
Clearance = 1500mm+10mm [(U01+U02)-129]
(Eq.09-13)
Where:
U01 = Maximum Phase-to-Ground Voltage of Line #1, over 50 kV
U02 = Maximum Phase-to-Ground Voltage of Line #2, over 50 kV
The clearance shall be maintained when one insulator string swings
upto its extreme position while the string of adjacent conductors
remains at rest.
A margin of 0.6m shall be added to the claculated values to account
for design errors.
The clearance shall be increased @ 3 % for each 300m in excess of
1,000m above mean sea level.
b.
Alternate Clearances for Voltages exceeding 98kV Phase-to-Ground
The clearances specified in equation 09-13 may be reduced for
circuits with known switching surge factor but shall not be less than
the clearances derived from the equation 09-7.
5.4.2
Vertical Clearance between Phase Conductors
a.
Basic Clearance
The vertical clearance between any crossing or adjacent conductors
carried on different supporting structures of the same or different
nominal voltages shall not be less than that shown in Table 09-9 or as
required by the following equation, whichever is larger.
Clearance = 600mm+10 [(U01-22)+(U02-22)]
(Eq.09-14)
Where:
U01 = Maximum phase-to-ground voltage of Line at upper level, over
22 kV
TESP12209R0/MAA
Date of Approval: December 12, 2007
PAGE NO. 17 OF 39
TRANSMISSION ENGINEERING STANDARD
TES-P-122.09, Rev. 0
U02 = Maximum phase-to-ground voltage of Line at lower level, over
22 kV
Table 09-9: Minimum Vertical Clearance between Conductors where the
Conductors of one Line cross over the Conductors of another
Lower Level Conductor
Type of Crossing
69kV Transmission Lines
110kV Transmission Lines
115kV Transmission Lines
69kV
(m)
1.10
-
Upper Level Conductor
Transmission Voltages (Line to Line)
110kV
115kV
132kV
230kV
(m)
(m)
(m)
(m)
1.40
2.10
1.60
-
1.70
-
2.40
380kV
(m)
3.10
3.30
3.40
132kV Transmission Lines
1.90
3.50
230kV Transmission Lines
3.20
4.10
380kV Transmission Lines
5.10
Distribution Lines
0.90
1.20
1.30
1.40
2.05
3.02
(34.5kVand below)
Overhead Ground Wire,
1.40
1.70
1.70
1.80
2.50
3.40
Guys and Span Wires
Communication Lines
2.0
2.20
2.30
2.50
3.10
4.10
Notes:
1. Additional margins of 1.0m and 2.0m (total 3.0m) shall be added to account for design
errors and wind induced dynamic conductor movement/safety during maintenance
operations respectively.
2.
The clearances shall be maintained under the conditions, when upper level conductors are at
the final unloaded sag at maximum design temperature of conductor and lower level
conductors are at the initial sag at the minimum design temperature of conductor or at final
unloaded sag under the same ambient condition without electrical loading whichever results
in larger difference.
3.
The clearances shall be increased @ 3 % for each 300m in excess of 1,000m altitude above
mean sea level.
b.
Alternate Clearances for Voltages exceeding 98 kV Phase-ToGround
The clearances specified in equation. 09-14 may be reduced where
the higher voltage circuit has a known switching surge factor but
shall not be less than the clearances derived from the equation 09-10.
TESP12209R0/MAA
Date of Approval: December 12, 2007
PAGE NO. 18 OF 39
TRANSMISSION ENGINEERING STANDARD
5.5
TES-P-122.09, Rev. 0
Clearance of Conductors from other supporting Structures
Conductors of one line passing near a lighting support, traffic signal support, or a
supporting structure of a second line, without being attached thereto, shall have
clearance from any part of the structure not less than calculated by the equation
below:
5.5.1
Horizontal Clearance
a.
Clearance “G” = 1500mm+10mm (U0-50)
(Eq.09-15)
Where U0 is the maximum operating voltage phase-to-ground, in
excess of 50kV.
Minimum horizontal clearance of a line conductor to a rigid
supporting structure, other than its own, based on the above equation
was calculated and tabulated in Table 09-10.
Table 09-10: Horizontal Clearance of Conductor from other
Supporting Structure
Nominal Voltage, (kV)
69
110
115
132
230
380
Minimum Horizontal Clearance of Conductor
from other Supporting Structure, (m)
1.50
1.70
1.75
1.85
2.50
3.50
Note: A margin of 0.6m shall be added to account for design errors and the
clearances shall be increased @ 3 % for each 300m in excess of 1,000m altitude
above mean sea level.
b.
These clearances have to be increased by the distance resulting from
horizontal swing of the conductor and insulator assembly due to
wind.
i.
The maximum insulator swing angle can be determined by
equation. 09-5.
ii.
The maximum design swing angle shall be based on a 1064
N/mm2 wind on the conductor, final sag at every day
temperature. The conductor swing shall be calculated as
follows:
φ = Arc Tan (Pc/Wc)
(Eq.09-16)
Where: Pc and Wc are defined in equation 09-6.
TESP12209R0/MAA
Date of Approval: December 12, 2007
PAGE NO. 19 OF 39
TRANSMISSION ENGINEERING STANDARD
TES-P-122.09, Rev. 0
The horizontal swing of conductors due to wind can be
obtained from the equation:
C = Sc x sin φ
(Eq.09-17)
Where: Sc is the conductor sag, shall be final sag based on
computed ruling span at every day temperature, with 1064
N/mm2 wind.
5.5.2
Vertical Clearance
Min. Clearance = 1700 mm + 10 mm (U0-50)
(Eq.09-18)
Where: U0 = Maximum operating Voltage Phase-to-Ground, in excess of
50kV.
Minimum vertical clearance of a line conductor to a rigid supporting
structure, other than its own, was calculated based on the above equation
and given in Table 09-11.
Table 09-11: Vertical Clearance of Conductor from other Supporting
Structure
Nominal Voltage, (kV)
69
110
115
132
230
380
Minimum Vertical Clearance of Conductor from
other Supporting Structure, (m)
1.70
1.90
1.95
2.05
2.70
3.70
Note: A margin of 1.0m shall be added to account for design errors and the clearances
shall be increased @ 3 % for each 300m in excess of 1,000m altitude above mean sea
level.
5.5.3
Alternate Clearance for Voltages exceeding 98kV to Ground
The clearances specified in equations 09-15 and 09-18 may be reduced for
circuits with known switching surge factors but shall not be less than the
values derived from the following equations.
a.
Min. horizontal clearance in mm
⎡ U (SSF) a ⎤
= 1500 + 1000⎢ L− G
⎥
500k
⎦
⎣
TESP12209R0/MAA
1.667
× bc
Date of Approval: December 12, 2007
(Eq.09-19)
PAGE NO. 20 OF 39
TRANSMISSION ENGINEERING STANDARD
b.
TES-P-122.09, Rev. 0
Min. vertical clearance
⎡ U (SSF) a ⎤
= 1800 + 1000⎢ L− G
⎥
500k
⎦
⎣
Where:
1.667
× bc
(Eq.09-20)
UL-G = The maximum crest operating voltage to ground
SSF = Maximum switching surge factor expressed in per-unit peak
voltage to ground (SSF value shall be obtained from
Transmission Asset Planning Department).
a = 1.15, the allowance for three standard deviations
b = 1.03, the allowance for nonstandard atmospheric conditions
c = Margin of safety, 1.2 for Vertical clearances and 1.0 for
horizontal clearances
k = 1.15, the configuration factor for Conductor-to-Plane gap
The clearances shall be increased @ 3 % for each 300m in excess of 450m
above mean sea level.
5.6
Clearances of Conductors from other Installations
The horizontal and vertical clearances of line conductors from other structures such
as tall buildings, signs, chimneys, TV masts, lighting poles, monuments in the
round-abouts,etc., shall be established as required, taking into consideration all local
conditions and the latest government and owner regulations.
5.6.1
Basic Clearance
Minimum clearances of wires, conductors and cables passing by, but not
attached to building and other installations, shall not be less than those
given in the following table. The horizontal clearance mentioned in the
table shall be maintained when the conductor swings upto the design swing
angle.
TESP12209R0/MAA
Date of Approval: December 12, 2007
PAGE NO. 21 OF 39
TRANSMISSION ENGINEERING STANDARD
TES-P-122.09, Rev. 0
Table 09-12: Minimum Clearance of Conductors Adjacent to but not attached to
Buildings and other Installations except Bridges (see notes 5 and 6)
Clearance of
Communication
Cables and
Grounded Guys
(m)
Phase Conductors
69kV
(m)
110kV
(m)
115kV
(m)
132kV
(m)
230kV
(m)
380kV
(m)
1.40
2.55
2.80
2.85
2.95
3.60
4.55
1.40
2.55
2.80
2.85
2.95
3.60
4.55
1.40
2.55
2.80
2.85
2.95
3.60
4.55
Above or below roof
or projection not
accessible
to
pedestrians (1)
0.90
4.05
4.30
4.35
4.50
5.10
6.10
Above or below
balconies and roofs
accessible
to
pedestrians (1)
3.20
4.35
4.60
4.65
4.80
5.40
6.35
Above
roofs
accessible to truck
traffic (2)
3.20
4.35
4.60
4.65
4.80
5.40
6.35
4.70
5.85
6.10
6.15
6.30
6.90
7.85
0.90
2.55
2.80
2.85
2.95
3.60
4.55
Buildings
(Horizontal)
To wall and
projections (3)
To
unguarded
windows (4)
To balconies and
areas accessible to
pedestrians (1)
Buildings (Vertical)
Above
roofs
accessible to vehicles
but not subject to
truck traffic
Signs,
Chimneys,
radio and television
antennas,
lighting
poles, monuments in
the
round-abouts
tanks
and
other
installations
not
classified
as
buildings:
Horizontal
Vertical above or
4.70
below
0.90
2.70
2.95
3.00
3.10
3.70
Notes:
1.
A roof, balcony or area is considered accessible to pedestrians if the means of access is through a
doorway, ramp, stairway or permanently mounted ladder.
2.
For the purpose of this rule, trucks are defined as any vehicle exceeding 2.45 m in height.
3.
This clearance may be reduced to 75 mm for the grounded portions of guys.
4.
Windows not designed to open may have the clearances permitted for walls and projections.
5.
6.
TESP12209R0/MAA
A margin of 1.0m shall be added to account for design errors.
The clearances shall be increased @ 3 % for each 300m in excess of 1,000m altitude
above mean sea level.
Date of Approval: December 12, 2007
PAGE NO. 22 OF 39
TRANSMISSION ENGINEERING STANDARD
5.6.2
TES-P-122.09, Rev. 0
Alternate Clearance for Voltages exceeding 98kV to Ground
The clearance specified in Table 09-12 may be reduced for circuit with
known switching surge factors but shall not be less than the values derived
from equations 09-19 and 09-20.
5.7
Midspan Clearance
The separation between the overhead ground wire and the top conductor is a
function of the actual structure footing resistance, wind speed, the number of
insulators in the insulator string, type of insulator, the span length and the acceptable
number of outages per 100 km per year.
5.7.1
The clearance at midspan between the overhead ground wires and the
conductors shall be greater than that at the structure and shall be well
coordinated so that the flashover occurs at the structure.
5.7.2
Line voltages have little relationship on the required midspan clearances.
The midspan clearances for SEC 69kV through 380 kV transmission lines
shall not be less than those tabulated below. The clearances shall be
maintained at every day temperarure, final sag with no wind and shall be
satisfied for the largest span encountered in a transmission line section.
The values for intermediate spans may be interpolated.
Table 09-13: Midspan Clearance Conductor to OGW
Span, (m)
Midspan Clearance Conductor to OGW, (m)
91
2.7
122
3.1
152
3.7
183
4.6
213
6.1
244
7.3
305
9.7
350
11.3
366
11.9
427
13.7
488
15.5
549
17.4
Note: The clearances shall be increased @ 3 % for each 300m in excess of 1,000m
altitude above mean sea level.
5.7.3
5.8
For spans longer than those in the above table, the final sag of the overhead
ground wire with no wind at every day temperature shall about 80 per cent
of conductor sag.
Air Gap Requirements
5.8.1
Shielded Lines
To maintain adequate clearances the air gap distance between any
conductor and structure shall be correlated to the insulation levels
TESP12209R0/MAA
Date of Approval: December 12, 2007
PAGE NO. 23 OF 39
TRANSMISSION ENGINEERING STANDARD
TES-P-122.09, Rev. 0
considering each of the three types of voltage stresses (lightning impulse,
switching surge and power frequency) under the condition at which each is
likely to govern and given in the following table.
Table 09-14: Air Gap Requirement for Shielded Lines
Line Voltage, (kV)
Air Gaps, (m)
69
0.69
110
1.30
115
1.30
132
1.50
230
2.1
380
2.60
Note: The clearances shall be increased @ 3 % for each 300m in excess of 1,000m
altitude above mean sea level.
5.8.2
Unshielded Lines
For unshielded lines the following criteria shall be used to specify
clearances of phase conductor to structure. Further the minimum conductor
to structure and conductor to conductor clearances shall not be less than
Eq. 09-1 to Eq. 09-20 or by the correlated air gap clearances to insulation
levels, the larger value shall be used, for various situations. Basic
clearances shall be based on the maximum system voltage under
emergency conditions.
6.0
a.
For the “no wind” or normal position of the insulator, the conductor
clearance to structure shall be the air gap equivalent of the insulator
string impulse flashover value plus ten (10) percent.
b.
For the 430 N/m2 wind position, the conductor clearance to structure
shall be the air gap equivalent of the insulator string impulse
flashover value.
c.
For 1064 N/m2 wind position, the conductor clearance to structure
shall be the air gap equivalent of 60Hz wet flashover value of the
insulator string. The air gap clearance plus the distance allowed for
the swing of insulator by the maximum wind of 1064 N/m2 will
determine the clearance from conductor to structure in the normal
position.
RIGHT-OF-WAY WIDTH REQUIREMENTS
6.1
General
6.1.1
TESP12209R0/MAA
Right-of-way requirements for 69 kV, 110kV, 115 kV, 132kV, 230 kV and
380 kV transmission lines are discussed in this part. All right-of-way shall
be secured before design and construction.
Date of Approval: December 12, 2007
PAGE NO. 24 OF 39
TRANSMISSION ENGINEERING STANDARD
6.1.2
6.2
TES-P-122.09, Rev. 0
Right-of-way for 69kV to 380kV transmission lines shall be as shown in
Tables 09-16 and 09-17, or shall be calculated using the equations 09-21 to
09-23. The larger value from these equations shall be used.
Conductor Clearance to edge of Right-of-Way
6.2.1
Minimum horizontal separation between phase conductors on the same
support shall be calculated by equations 09-1 to .09-4. The large value
from these equations shall be used. This value shall be increased by the
distance to the end of the longest insulator support on each line structure.
6.2.2
Minimum horizontal clearances from conductors to edge of right-of-way
shall be based on values in Tables 09-16 and 09-17 or in accordance with
the following equations. The larger value shall be used. Transmission
voltages shall be based on maximum operating voltage under emergency
conditions:
a.
Basic Clearance
= 2300 mm + 10 mm (U0-22)
(Eq.09-21)
Where:
U0 = Maximum operating voltage phase-to-ground over 22 kV.
b.
Alternate clearance in mm
⎡ U (SSF) a ⎤
= 1500 + 1000⎢ 0
⎥
⎣ 500k ⎦
Where:
1.667
× bc
(Eq.09-22)
U0 = Maximum alternating current crest operating voltage to ground
SSF = Maximum switching surge factor expressed in per unit peak
voltage to ground. (SSF value shall be obtained from Transmission
Asset Planning Department).
a = 1.15, the allowance for three standard deviations.
b = 1.03, the allowance for nonstandard atmospheric conditions
c = Margin of safety, 1.2 for Vertical clearances and 1.0 for
Horizontal clearances
k = 1.15, the configuration factor for Conductor-to-Plane gap.
TESP12209R0/MAA
Date of Approval: December 12, 2007
PAGE NO. 25 OF 39
TRANSMISSION ENGINEERING STANDARD
6.3
TES-P-122.09, Rev. 0
Right-of-Way Width Requirements for Single Transmission Line
6.3.1
Figure TE-2209-0200-00 shows the procedures to be followed to establish
the right-of-way for various types of transmission line structures in
restricted areas.
6.3.2
Explanation of symbols used in Figure TE-2209-0200-00 and steps to be
taken to establish right-of-way requirements in restricted areas are given
below:
A = Distance from centerline of structure to insulator attachment in mm.
φ1 = Angle of maximum swing for suspension insulator string.
preferred to use the φ1 as 45° swing.
It is
If 45° swing is used, it will include most conditions for structures currently
being used with the insulator string at maximum blowout or structure
design limitations.
If the minimum right-of-way is required to be obtained for a special area
control then the actual conditions or φ1 may be calculated for the worst
conditions of the line under consideration.
B = Offset due to insulator swing for suspension insulators equal to length
of insulator string plus hardware length times Sin φ1
φ2 = Angle of maximum swing for conductors is determined by multiplying
the conductor diameter in meters by the wind pressure in N/mm2 on
conductor and dividing by the conductor unit weight in Newtons per
meter.
Tan φ 2 =
Conductor Dia x Wind Pressure
Unit Weight
(Eq.09-23)
C = Offset due to conductor sag x Sin φ2. Conductor sag shall be the final
sag based on computed ruling span at every day temperature with
1064 N/mm2 wind
D = Horizontal clearance from conductor to edge of right-of-way at
maximum swing calculated for conditions established for structure to
be used (see clause 6.2.2)
E = Total distance each side, from centerline to edge of right-of-way.
6.4
Right-of-Way Width Requirements for Parallel Transmission Lines
6.4.1
TESP12209R0/MAA
Figures TE-2209-0300-00 and TE-2209-0400-00 show the procedures to
be followed in order to establish the minimum right-of-way for typical
configurations of parallel transmission lines.
Date of Approval: December 12, 2007
PAGE NO. 26 OF 39
TRANSMISSION ENGINEERING STANDARD
6.4.2
TES-P-122.09, Rev. 0
Steps A through E, as in clause 6.3.2, shall be followed and the angles φ1
and φ2 shall be determined for each of the two lines that are being
paralleled. Then determine the dimensions required for Items F and G.
The larger of these two shall determine the distance between the parallel
transmission lines.
a.
Separation between lines as dictated by minimum clearance between
conductors carried on different Supports
The horizontal clearance between a phase conductor of one line to a
phase conductor of another line shall meet the following conditions:
(a) both phase conductors displaced by a 1064 N/mm2 wind at every
day temperature, final sag; (b) if insulators are free to swing, one
shall be assumed to be displaced by a 1064 N/mm2 wind while the
other shall be assumed to be unaffected by the wind (see Figure TE2209-0300-00).
F = Clearance between conductors of parallel transmission lines as
determined by equation 09-3 and 09-4 for phases of different
circuits.
b.
Separation between lines as dictated by minimum clearance of
conductors from one line to the supporting structure of another
The horizontal clearance of a phase conductor of one line to the
supporting structure of another when the conductor and insulator are
displaced by a 1064 N/mm2 wind at every day temperature final sag.
G = Clearance of conductor from other supporting structures, as
determined by the equation 09-15.
6.4.3
6.5
The separation between lines will depend upon the spans and sags of the
lines as well as how the structures of one line line-up with structures of
another. In order to avoid the unreasonable task of determining the
separation of the structures span-by-span, a standard separation value shall
be used based on a worst case analysis. Thus if structures of one line do not
always line-up with the other, the separation required by clause 6.4.2.b
above shall be based on assumption that the structure of one line is located
next to the mid-span point of the line that has the most sag.
Example Calculation of Right-of-Way
6.5.1
Information needed to determine the right-of-way requirements for
structure types of any transmission lines are tabulated on Table 09-15.
6.5.2
Typical calculations for a single 230kV double circuit steel tower with 22
units of suspension insulator per string, 402.6 mm² (795 kcmil), 26/7
strands ACSR/AW “Drake” conductor and 335 meters ruling span are:
a.
TESP12209R0/MAA
Dimension ‘A’
Date of Approval: December 12, 2007
PAGE NO. 27 OF 39
TRANSMISSION ENGINEERING STANDARD
TES-P-122.09, Rev. 0
A = 11.9 m derived from the drawing for “Latticed Steel Delta
Configuration 230 kV Double Circuit Tangent Type Tower
TTN (0°-1°)”. Dimension ‘A’ depends on tower structure
design and configuration.
b.
Dimension ‘B’
Assume φ1 = 45°
Length of insulator string = 22 x 0.146 m = 3.2 m
Length of hardware string = 2 x 0.400 m = 0.8 m
Total length of Insulator String = 4.0 m
B = Total length of Insulator String x Sin φ1
= 4.0 m x sin 45° = 2.83 m
c.
Dimension ‘C’
Angle of maximum swing for conductors:
⎛ 28.1 mm / 1000 x 1064 ⎞
φ2 = Arc Tan ⎜
⎟ = 63 °
15.2 N/m
⎠
⎝
Sag for 335 m ruling span = 10.64 m at 27°C, final with 1064 N/mm2
wind
Offset due to conductor swing:
C = 10.64 m x sin 63° = 9.50 m
Offset due to conductor swing for two bundled conductor:
Cl = 9.5 m +
d.
0.5
x Cos 63o = 9.72 m
2
Dimension ‘D’
Horizontal clearance to edge of right-of-way
⎛ 253
⎞
D = 2300mm + 10 mm ⎜
− 22⎟
⎝ 3
⎠
D = 2300 mm + 1241 mm = 3541 mm, say 3.60 m or by equation
09-22 for circuit with known switching surge factors:
TESP12209R0/MAA
Date of Approval: December 12, 2007
PAGE NO. 28 OF 39
TRANSMISSION ENGINEERING STANDARD
⎡ U (SSF) a ⎤
D = 1500 mm + 1000⎢ L-G
⎥⎦
500k
⎣
e.
TES-P-122.09, Rev. 0
1.667
× bc
Dimension ‘E’
Distance each side of centerline to edge of right-of-way
E = A+ B+ C+ D = 11.9 + 2.83 + 9.72 + 3.60 = 28.05 m
Therefore, total width of right-of-way required shall be:
2 x E = 2 x 28.05 m = 56.10 m; say ROW = 56 m
6.5.3
Typical calculation for two parallel 230kV steel tower lines (Figure TE2209-0300-00)
Tower configurations are the same as in clause 6.5.2. The separation
between two parallel 230 kV steel tower lines shall be calculated by the
two equations shown below and greater value shall be considered:
Items A, B, C, D, and E to be calculated as in clause 6.5.2.
a.
Horizontal Clearance between different phases of different circuits
according to conductor sag per equation 09-3 & 09-4
U ⎤
⎡U
F = 7.6mm ⎢ 1 + 2 ⎥ + 8 2.12S
3⎦
⎣ 3
Where:
U1 = U2 = 230 kV x 1.1 = 253kV
S = Sag at 27°C, final with 1064 N/mm2 wind
F = 7.6mm [146 + 146] + 8 2.12(10640)
= 2220 + 1202 = 3422 mm; say 3.4 m
b.
Horizontal Clearance of conductor of one line to the supporting
structure of another (Eq.09-15)
⎛U
⎞
G = 1500mm + 10.2⎜ 1 − 50⎟
⎝ 3
⎠
= 1500 + 10 (146-50)
TESP12209R0/MAA
Date of Approval: December 12, 2007
PAGE NO. 29 OF 39
TRANSMISSION ENGINEERING STANDARD
TES-P-122.09, Rev. 0
= 1500 + 960 = 2,460 mm, say. 2.50 m
c.
Horizontal Clearance may be reduced by the equation for circuits
with known switching surge factors by the (Eq.-09-18).
⎡ U(SSF) a ⎤
Min. Clearance G = 1500 + 1000⎢
⎥
⎣ 500k ⎦
1.667
× bc
F = 3.40 m is larger than G, therefore, it is to be considered
Total right-of-way width shall be: E + A + B + C + F + A + E
= 28.05+11.9+2.83+9.72+3.4+11.9+ 28.05= 95.85 m
Say total ROW = 96 m
Table 09-15: Sample Data for Right-Of-Way Calculation
Sr. No.
Description
Line No. 1 & 2
1
Maximum Line Voltage
2
Type of Structure
3
Drawing for Tower Type TTN
4
Centerline distance to end of longest
insulator, m
5
Number of insulators in the string
22
6
Insulator length, m
4.0
7
Insulator assembly weight, kg
127
8
Conductor
Drake, ACSR/AW
9
Stranding
26/7
10
Weight per unit, kg/m
1.551
11
Diameter, mm
28.14
12
Ruling span, m
335
13
Sag at 27° with 1064 N/m2 wind, m
TESP12209R0/MAA
Date of Approval: December 12, 2007
253kV
Lattice Steel
(Delta Configuration)
11.9
10.64
PAGE NO. 30 OF 39
TRANSMISSION ENGINEERING STANDARD
TES-P-122.09, Rev. 0
Table 09-16: Single Transmission Lines Right-of-Way Width Requirements
Line Voltage
(kV)
380
230
110/115/132
Conductor
Ruling
Span
(m)
Maximum
Span
(m)
Normal
ROW
Width
(m)
ACAR
400
550
85
AAAC/ACA
R
400
550
70/75
ACSR
400
550
50*
ACSR
305-350
400
56
ACSR
305-350
400
45
ACSR
200
250
35
305-350
400
35/50
200
250
30
ACSR
260-275
320
30
ACSR
80-100
110-120
15
ACSR
305-350
400
30
Wood H-Frame, S/C
ACSR
260-275
320
25
Wood/Steel
Monopole, S/C &
D/C
ACSR
80-120
140
15
Structure
Lattice Steel, S/C
(Horizontal)
Lattice Steel, D/C
(Vertical, V-String)
Lattice Steel, D/C
(Vertical, I-String)
Lattice Steel, D/C
(Delta)
Lattice Steel, D/C
(Vertical)
Steel Monopole,
D/C (Vetical)
Lattice Steel, D/C
(Vertical/Delta)
Steel Monopole,
D/C (Vetical)
Wood H-Frame, S/C
Wood/Steel
Monopole, S/C &
D/C
Lattice Steel, D/C
(Vertical)
69
AAAC/ACS
R
ACSR/AAA
C
Notes:
i.
ROW marked with * is applicable in the Inland Area where creepage distance is
31mm/kV.
ii.
The figures indicated in the above Table shall be applicable when ROW is unrestricted. In case of restricted ROW the exact value shall be established based on
the actual span length and the actual conductor data.
iii.
Wherever right-of-way is restricted and not possible to accommodate structure pads
and access road per TES-P-122.11, SEC shall review the case to determine
appropriate right-of-way.
TESP12209R0/MAA
Date of Approval: December 12, 2007
PAGE NO. 31 OF 39
TRANSMISSION ENGINEERING STANDARD
TES-P-122.09, Rev. 0
Table 09-17: Parallel Transmission Lines Right-of-Way Width Requirements
Line Voltage
(kV)
380
380
380
380
380
Structure
Lattice Steel, S/C
(Horizontal)
Lattice Steel, S/C
(Horizontal)
Lattice Steel, D/C
(Vertical)
Lattice Steel, D/C
(Vertical)
Lattice Steel, D/C
(Vertical, I-String)
Lattice Steel, D/C
(Vertical, I-String)
Lattice Steel, S/C
(Horizontal)
Lattice Steel, D/C
(Vertical)
Lattice Steel, S/C
(Horizontal)
Conductor
Ruling Span
(m)
Maximum
Span
(m)
ACAR
400
550
ACAR
400
550
ACAR/AAAC
400
550
ACAR/AAAC
400
550
ACSR
400
550
139
119
100
ACSR
400
550
ACAR
400
550
ACAR
400
550
ACAR
400
550
125
Lattice Steel, D/C (Delta)
ACSR
335-350
400
380
Lattice Steel, D/C
(Vertical)
ACAR
400
550
230
Lattice Steel, D/C (Delta)
ACSR
335-350
400
ACAR
400
550
ACSR
335-350
400
ACAR
400
550
ACSR
335-350
400
ACAR
400
550
ACSR
200
250
ACSR
400
550
230
380
230
380
230
380
132
380
132
380
115/110
380
115
Lattice Steel, S/C
(Horizontal)
Lattice Steel, D/C
(Vertical)
Lattice Steel, D/C
(Vertical)
Lattice Steel, D/C
(Vertical)
Lattice Steel, D/C
(Vertical)
Steel Monopole, D/C
(Vertical)
Lattice Steel, D/C
(Vertical, I-String)
Lattice Steel, D/C
(Vertical, I-String)
Lattice Steel, D/C
(Vertical, I-String)
Steel Monopole, D/C
(Vertical)
Lattice Steel, D/C
(Vertical)
Lattice Steel, D/C
(Vertical)
Lattice Steel, D/C
(Vertical)
Lattice Steel, D/C (Delta)
*
129
230
380
Normal
ROW
Width
(m)
115
115
104
95
*
83
ACSR
335-350
400
ACSR
400
550
*
75
ACSR
200
250
ACAR/AAAC
400
550
ACSR/AAAC
335-350
400
ACAR
400
550
ACSR
335-350
400
93
105
* Applicable in the Inland Area where creepage distance is 31mm/kV.
TESP12209R0/MAA
Date of Approval: December 12, 2007
PAGE NO. 32 OF 39
TRANSMISSION ENGINEERING STANDARD
TES-P-122.09, Rev. 0
Table 09-17: Parallel Transmission Lines Right-of-Way Width Requirements
(Continued)
Line Voltage
(kV)
380
69
Structure
Lattice Steel, D/C
(Vertical)
Lattice Steel, D/C
(Vertical)
Conductor
Ruling Span
(m)
Maximum
Span
(m)
ACAR
400
550
88
ACSR
335-350
400
Lattice Steel, D/C (Delta)
ACSR
335-350
400
Lattice Steel, D/C (Delta)
ACSR
335-350
400
Lattice Steel, D/C (Delta)
ACSR
335-350
400
ACSR
335-350
400
ACSR
335-350
400
ACSR
335-350
400
ACSR
200
250
ACSR
200
250
230
230
230
230
Normal
ROW
Width
(m)
96
Lattice Steel, D/C
(Vertical)
Lattice Steel, D/C
(Vertical)
Lattice Steel, D/C
(Vertical)
Steel Monopole, D/C
(Vertical)
Steel Monopole, D/C
(Vertical)
85
74
60
230
Lattice Steel, D/C (Delta)
ACSR
335-350
400
115
Lattice Steel, D/C (Delta)
ACSR
335-350
400
ACSR
335-350
400
ACSR
335-350
400
ACSR
200
250
ACSR
200
250
ACSR
200
250
ACSR
80-120
140
ACSR
335-350
400
ACSR
80-120
140
ACSR
335-350
400
ACSR
80-120
140
ACSR
335-350
400
91
230
115
230
115
230
69
230
69
230
69
132
132
TESP12209R0/MAA
Lattice Steel, D/C
(Vertical)
Lattice Steel, D/C
(Vertical)
Steel Monopole, D/C
(Vertical)
Steel Monopole, D/C
(Vertical)
Steel Monopole, D/C
(Vertical)
Steel/Wood Monopole,
D/C (Vertical)
Lattice Steel, D/C (Delta)
Steel/Wood Monopole,
D/C (Vertical)
Lattice Steel, D/C
(Vertical)
Steel/Wood Monopole,
D/C (Vertical)
Lattice Steel, D/C
(Vertical, I-String)
Lattice Steel, D/C
(Vertical, I-String)
Steel Monopole, D/C
(Vertical)
Steel Monopole, D/C
(Vertical)
73
55
45
64
55
*
65
ACSR
335-350
400
ACSR
200
250
*
45
ACSR
Date of Approval: December 12, 2007
200
250
PAGE NO. 33 OF 39
TRANSMISSION ENGINEERING STANDARD
TES-P-122.09, Rev. 0
Table 09-17: Parallel Transmission Lines Right-of-Way Width Requirements
(Continued)
Line Voltage
(kV)
132
Structure
Steel Monopole, D/C
(Coastal Area)
Steel Monopole, D/C
(Coastal Area)
Lattice Steel, D/C
(Vertical)
Lattice Steel, D/C
(Vertical)
Steel Monopole, D/C
(Vertical)
Steel Monopole, D/C
(Vertical)
Conductor
Ruling Span
(m)
Maximum
Span
(m)
ACSR/AAAC
200
250
55
ACSR/AAAC
200
250
ACSR/AAAC
335-350
400
ACSR/AAAC
335-350
400
ACSR/AAAC
200
250
ACSR/AAAC
200
250
Lattice Steel, D/C (Delta)
ACSR
335-350
400
Lattice Steel, D/C (Delta)
ACSR
335-350
400
ACSR
335-350
400
ACSR
335-350
400
ACSR
200
250
ACSR
200
250
H-Frame Wood, S/C
ACSR
260-275
320
H-Frame Wood, S/C
ACSR
260-275
320
H-Frame Wood, S/C
ACSR
260-275
320
Wood Pole, S/C
ACSR
80-100
110-120
Wood Pole, S/C
ACSR
80-100
110-120
Wood Pole, S/C
ACSR
80-100
110-120
115
H-Frame Wood, S/C
ACSR
260-275
320
69
H-Frame Wood, S/C
ACSR
260-275
320
115
H-Frame Wood, S/C
ACSR
260-275
320
69
Wood Pole, S/C
ACSR
80-100
110-120
115
Wood Pole, S/C
ACSR
80-100
110-120
69
Wood Pole, S/C
ACSR
80-100
110-120
H-Frame Wood, S/C
ACSR
260-275
320
H-Frame Wood, S/C
ACSR
260-275
320
110
110
65-70
55
115
115
115
Normal
ROW
Width
(m)
86
Lattice Steel, D/C
(Vertical)
Lattice Steel, D/C
(Vertical)
Steel Monopole, D/C
(Vertical)
Steel Monopole, D/C
(Vertical)
65
55
115
60
115
38
115
23
45
37
21
69
TESP12209R0/MAA
42
Date of Approval: December 12, 2007
PAGE NO. 34 OF 39
TRANSMISSION ENGINEERING STANDARD
TES-P-122.09, Rev. 0
Table 09-17: Parallel Transmission Lines Right-of-Way Width Requirements
(Continued)
Line Voltage
(kV)
Structure
Conductor
Ruling Span
(m)
H-Frame Wood, S/C
ACSR
260-275
Maximum
Span
(m)
320
69
Normal
ROW
Width
(m)
23
Wood Pole, S/C
ACSR
80-100
110-120
Wood Pole, S/C
ACSR
80-100
110-120
Wood Pole, S/C
ACSR
80-100
110-120
69
20
Note: Wherever right-of-way is restricted and not possible to accommodate structure pads
and access road per TES-P-122.11, SEC shall review the case to determine appropriate
right-of-way.
7.0
BIBLIOGRAPHY
7.1
Design Manual for High Voltage Transmission Lines, REA Bulletin 1724E200, U.S. Department of Agriculture, 2005 Edition
7.2
Transmission Line Design Manual, U.S. Department of the Interior,
Holland H. Farr
7.3
National Electrical Safety Code, American National Standard Institute, 2007
Edition
7.4
IEC 61936-1, Power Installations Exceeding 1 kV A.C.-Part 1: Common Rules
7.5
Electrical Transmission and Distribution Refence Book, Central Station
Engineers (Westinghouse Electric Corporation), 1964
7.6
Estimating Lightning Performance of Transmission Lines, IEEE Transactions
Volume 83, 1964, J.M. Clayton & F.S. Young
7.7
Shielding of Transmission Lines, IEEE Paper No. 63-640, J.M. Clayton, F.S.
Young and A.R. Hileman
7.8
Application of Insulators in a Contaminated Environment, IEEE Transaction
7.9
Elements of Power System Analysis, William D. Stevens, Jr.
TESP12209R0/MAA
Date of Approval: December 12, 2007
by
PAGE NO. 35 OF 39
TRANSMISSION ENGINEERING STANDARD
TESP12209R0/MAA
Date of Approval: December 12, 2007
TES-P-122.09, Rev. 0
PAGE NO. 36 OF 39
TRANSMISSION ENGINEERING STANDARD
TESP12209R0/MAA
Date of Approval: December 12, 2007
TES-P-122.09, Rev. 0
PAGE NO. 37 OF 39
TRANSMISSION ENGINEERING STANDARD
TESP12209R0/MAA
Date of Approval: December 12, 2007
TES-P-122.09, Rev. 0
PAGE NO. 38 OF 39
TRANSMISSION ENGINEERING STANDARD
TESP12209R0/MAA
Date of Approval: December 12, 2007
TES-P-122.09, Rev. 0
PAGE NO. 39 OF 39