www.dalekovod.com
Steel lattice towers
for 10, 20 and 35 kV transmission lines
INSTRUCTIONS FOR DEPLOYMENT OF TOWERS
Publisher: DALEKOVOD-PROJEKT d.o.o., 2010.
e-mail: dalekovod.projekt@dalekovod.hr
Ovitak engleski.indd 1
PROJEKT
3/26/10 2:20 PM
STEEL LATTICE TOWERS FOR 10, 20 AND 35 kV TRANSMISSION LINES
TABLE OF CONTENTS
1.
INTRODUCTION
3
2.
BASIC INFORMATION ON PURPOSE AND STRUCTURE OF TOWERS
3
3.
CONDUCTOR ARRANGEMENT ON THE TOWER
5
3.1.
3.2.
TOWER HEAD TYPES
OPTIONS FOR MODELLING TOWER HEADS
5
7
4.
TOWER TYPES AND STRENGTH CAPACITY
8
4.1.
4.2.
TOWER TYPES
TABLE WITH DRAFTS AND DATA ON ADMISSIBLE TOWER LOADS
NAH2
NAL2
NAP2
ZAE2
ZAH2
ZAJ2
ZAL2
ZAM2
EXAMPLE OF SELECTING AND MONITORING TOWERS
FOR CERTAIN LOAD CONDITIONS
4.3.
8
9
10
11
12
13
14
15
16
17
18
5.
RECOMMENDED SELECTION OF TOWERS (APPLICATION TABLES)
5.1.
MOST COMMON STRUCTURE AND CROSS SECTIONS
FOR NON INSULATED CONDUCTORS IN DIFFERENT CLIMATE CONDITIONS
21
5.2.
5.3.
CONDUCTOR SUSPENSION SETS
CONDUCTOR TENSION SETS
23
32
6.
ORDERING INFORMATION AND STRUCTURE TAKEOVER
34
7.
ASSEMBLING THE STRUCTURE
36
8.
TOWER FOUNDATION
38
1
21
DALEKOVOD - PROJEKT
1. INTRODUCTION
In order to comprise all requirements of distributors, and at the same time use the simplest possible storage solutions
and to reduce maintenance costs i.e. to unify the construction, a suitable group of steel lattice towers was designed for
assembling 20 (10 and 35) kV distribution lines. Towers were designed between 1980 and 1983 for the requirements of
the Elektroprivreda company, as part of the medium voltage tower standardisation program for ZEOH at that time, and
are now part of the DALEKOVOD d.d. Zagreb manufacturing assortment.
By using extensive experience in design, production and construction of transmission line towers and data on their use,
3 suspension (N – NAH, NAL and NAP) and 5 tension (Z – ZAE, ZAH, ZAJ, ZAL and ZAM) towers were designed, in line
with the “Regulation on Technical Standards for Construction of Overhead Power Lines of Nominal Voltage Between 1
and 400 kV” Official Gazette 65/88 (O.G.RH 55/96), where each of them can be used in different conditions present on
the transmission line route.
For each tower type a structure prototype was made and it was tested under test load. Based on the examination of the
project documentation (calculations and manufacturing blueprints), examination of the prototype structure, testing
results and by participation in tests, IGH as the authorised organisation issued attests on testing.
Over 25 years of experience in using towers indicated all structural advantages, precisely because of the possibility
of their differentiated use, their suitability to most common situations and deployment requirements. Accordingly,
new types of accessorises and new manufacturing technology improvements were made to: the structure itself,
presentation of acceptable loads and methods for control and selection of the structure model for the relevant load of
each single tower design type group. To the names of towers the additional mark 2 was added, (N – NAH2, NAL2 and
NAP2) and (Z – ZAE2, ZAH2, ZAJ2, ZAL2 and ZAM2).
For each single tower type a project documentation was prepared according to the currently valid technical regulations
and professional HEP standards (Steel Lattice Tower Standardisation for 20(10) kV Network, mark N.022.03, class no.
4.08/92).
These instructions are intended for designers, builders and contractors of medium voltage transmission
lines, as also to employees in charge of their maintenance, and are to insure quick and simple reference in
selecting and deploying structures, i.e. in reaching the optimum solution.
2
STEEL LATTICE TOWERS FOR 10, 20 AND 35 kV TRANSMISSION LINES
2. BASIC INFORMATION ON PURPOSE AND
STRUCTURE OF TOWERS
2. 1. THE PURPOSE OF THE STRUCTURE
With difference from towers designed for very specific cross sections and structures of conductors, these towers
represent typified structure solutions where each type can be used in different geographical conditions for more
different types of conductors, with different cross sections and structures.
For the required conductor cross-section and specific locations, by correct selection of the maximum working stress
and corresponding arrangement of suspensions, i.e. points of connecting the earth wire to the structure, each tower
can be used:
in all climate conditions:
•
nominal wind load 500 – 1100 (1300) N/m2
•
additional load coefficient 1 to 4 x 0.18.d daN/m’
on all terrains, without regard of the configuration
for earth wires with different cross-sections:
•
AL/Č between 35/6 mm2 and 150/25 mm2
•
other types of insulated and non insulated conductors, that put weight on the tower
with the corresponding resulting tension force and wind facing surface
for connecting post type, long rod, string insulators (directly to the cross-arm, over hinges, shackles, extension
links and spacers)
for one, and for two systems
with, or without earth wire
for use of additional equipment without requiring customisation of the structure:
•
overhead and underground cable tap-offs, overhead-underground transition
•
line disconnectors (with or without remote control), malfunction detection, etc.
as gantries
3
DALEKOVOD - PROJEKT
2. 2. BASIC STRUCTURE INFORMATION
Towers are four sided pyramids of steel - lattice grid. Made of standard hot rolled profiles connected with bolts, with
single diagonal filling in the total length of the tower. Two sides of suspension towers that are designed for light and
medium loads shall be made of horizontal steel plate welded to tower main legs instead of diagonals fixed with bolts.
Corrosion protection of all tower parts is made by hot dip galvanizing, in quality that satisfies renown world standards.
All towers are designed with parallel sides of the upper section (tower head without incremental adjustments). In this
way it is possible to use same cross-arms for different disposition of earth wires – numerous different symmetrical and
asymmetrical heads, and makes possible to connect same accessories on different tower heights as also on different
types of towers.
Tower sections with incremental adjustment are selected on purpose to use one or at most two different profile
dimensions for tower main legs at all heights. Each tower section diagonal has the same length, profile dimension and
corresponding bolts.
Type, material, dimensions and manufacturing of tower structures enable:
simple storage and transport (for different dimensions and transportation means)
quick installation and removal (by elements, sections, as a whole) with or without mechanisation
changing the function of a tower on the already constructed transmission lines
simple maintenance and interventions during exploitation:
•
open profiles suitable for monitoring and maintenance
•
simple replacement of damaged elements and reparation of corrosion protection
4
STEEL LATTICE TOWERS FOR 10, 20 AND 35 kV TRANSMISSION LINES
3. CONDUCTOR ARRANGEMENT
ON THE TOWER
3. 1. TOWER HEAD TYPES
On towers it is possible to have virtually any arrangement of conductors i.e. any tower head type.
Types used for non insulated conductors are:
Symmetrical heads formed by two sided cross-arms
•
G – gama
•
D – delta
•
T – trapez [trapezium]
•
B, BU – bačva [barrel] (B without, and BU with the earth wire)
Asymmetrical heads formed by one sided cross-arms
•
J, JU – jela [fir] (J without, and JU with the earth wire)
Cross-arms are mounted on the upper section of the tower with the possibility of connection on every 0.85 m of the
section, where necessary. For the central conductor of the head D and for the earth wire on heads BU and JU, the top
frame structure is mounted at the top of the tower, hereinafter named only as – top.
Besides cross-arms for types of tower heads, it is also possible to attach on towers suspension equipment and structures
(frames, cross-arms, etc.) customised for suspending insulated conductors, cables, devices, etc.
5
DALEKOVOD - PROJEKT
TOWER HEAD TYPES
SYMMETRICAL HEADS
G - GAMA
D - DELTA
B, BU - BAČVA [BARREL]
T - TRAPEZ [TRAPEZIUM]
ASYMMETRICAL
HEADS
HEAD CONSTRUCTION
CROSS-ARM LENGTH
a, b, c = 0.95 1.20. 1.45. 1.60 (1.80)m
SPACING BETWEEN CROSS-ARMS
HEAD HEIGHT
USEFUL TOWER HEIGHT
DESIGNATION OF THE HEAD SHAPE
G, D, B, T, J = towers without earth wire
BU, JU = towers with earth wire
J, JU - JELA [FIR]
6
x, y, z = nx0.85m
s=x+y+z
h=H-S
x=0
x = n x 0.85
STEEL LATTICE TOWERS FOR 10, 20 AND 35 kV TRANSMISSION LINES
3. 2. OPTIONS FOR MODELLING TOWER HEADS
SYMMETRICAL
HEAD CROSS-ARMS
ASYMMETRICAL
HEAD CROSS-ARMS
DOUBLE SIDED CONSOL
ONE SIDED CONSOL
TOP
7
DALEKOVOD - PROJEKT
4. TOWER TYPES AND STRENGTH CAPACITY
4. 1. TOWER TYPES
Basic purpose:
suspension – line towers in the transmission line route: NAH2, NAL2, NAP2
tension: ZAE2, ZAH2, ZAJ2, ZAL2, ZAM2
The order of towers corresponds to the tower weight order and their implementation from lighter conditions towards
the heavier load on the transmission line route.
Tension towers for transmission lines, besides their main purpose to decrease the load, angle-tension, end-tower and
towers with tap-offs, can also be used as suspension ones (in case larger medium spans and/or higher towers are
required).
Nominal height: 9 m, 11 m, 13 m, 15 m – all towers (tower NAH2 up to 13 m for standard use)
17 m, 19 m and 21 m – additional height for tension towers
Nominal heights are specific for all tower types, and they should be used when placing orders. The actual height from
bottom to top, according to the manufacturing documentation is equal to nominal height with tolerance between 0.5 m and + 0.25 m, depending on the tower type and height. It is indicated on the sketch of each tower, above the
nominal height indicated in brackets. Tower height from the connection point on the tower top to the ground is equal
to the real height of the structure, according to the sketch of the tower + height of the foundation. Overall standard
increase of height from the foundations amounts to 30 cm and can be increased for certain tower locations if necessary.
To reduce the costs of solving property issues when constructing transmission lines, additional tower heights were
designed. They make possible to use towers with longer spans and to reduce the number of towers in the transmission
line route.
TOWER STRENGTH CAPACITY - NOMINAL TOWER LOAD
The strength capacity of each single tower is conditioned by the basic implementation i.e. load conditions for which
the tower is designed for, and are defined by the nominal load and allowed torque with the resulting sum of horizontal
forces. Nominal load corresponds to the maximum force on the top of the tower, that tower main legs can support for
certain load according to the mentioned Regulation for Overhead Power-lines. Values stated for loads caused by wind
relate to payload.
The strength capacity of each tower is controlled by testing the structure prototype used for its basic purpose, and this
is certified by the adequate attest.
8
STEEL LATTICE TOWERS FOR 10, 20 AND 35 kV TRANSMISSION LINES
4. 2. TOWER TABLES
According to the table of allowed tower loads it is possible to select, i.e. to monitor the tower for different types of the
head and for different load combinations (standard use, additional tap-offs, during reconstruction, repairs, etc.).
Tables also state the recommended dimensions of the foundation for specific tower heights in relation to the
characteristic soil bearing capacity, and approximate weight of the tower structure without cross-arms.
9
DALEKOVOD - PROJEKT
Tower type mark
NAH2
Nominal voltage
20 (35) kV
Nominal tower height(s)
9, 11, 13 m
Nominal load
Rx, Ry
(allowed horizontal load Hx and Hy reduced to the
tower top - over the tower height)
Basic load safety factor
1.5
Exceptional load safety factor
1.1
Wind force on the structure
2.6xW
SUSPENSION TOWER NAH2
SIDE X
SIDE Y
1.
Basic wind
load - W
Nominal
tower height
N/m2
m
9
11
13
(15)
9
11
13
(15)
9
11
13
(15)
9
11
13
9
11
13
500
600
750
900
1100
2.
Cross-arm
length
a, b, c
m
0.95
1.20
1.45
1.60
art. 69.1
exceptional
load
Admissible load on the cross-arm top:
Hy
Vz
art. 69.1
art. 68.1a, 69.1.
kN
3.25
7.00
2.70
5.00
2.30
3.40
1.90
2.80
Nominal
tower
height
Tower
weight
Foundation
part
L
Soil
σdop
m
kg
cm
9
290
139
11
360
141
13
420
146
kN/m2
120 + PV
150
200 + PV
250
≥500
120 + PV
150
200 + PV
250
≥500
120 + PV
150
200 + PV
250
≥500
EXCAVATION PERIMETER EXCAVATION PERIMETER
TOWER FOUNDATION
10
Nominal load for ∑ Vz = 8kN
Rx (Ry=0)
Ry (Rx=0)
art. load 68.1b
art. load 68.1c
kN
5.5
3.3
4.8
2.5
4.6
2.1
3.7
1.4
5.4
3.1
4.6
2.2
4.4
1.7
3.5
1.0
5.2
2.7
4.3
1.9
4.1
1.3
2.4
0.6
5.0
2.5
4.0
1.5
3.7
0.9
4.7
2.0
3.6
0.9
1.8
0.4
Foundation
dimensions
A
T
cm
80
190
60
180
80
170
60
160
60
150
80
200
60
190
80
180
60
170
60
150
80
200
60
190
80
180
60
170
60
150
STEEL LATTICE TOWERS FOR 10, 20 AND 35 kV TRANSMISSION LINES
Tower type mark
Nominal voltage
Nominal tower height(s)
Nominal load
(allowed horizontal load Hx and Hy reduced
to the tower top - over the tower height or 10.3 m)
Basic load safety factor
Exceptional load safety factor
Wind force on the structure
SUSPENSION TOWER NAL2
SIDE X
SIDE Y
1.
Basic wind
load - W
Nominal
tower height
N/m2
m
9
11
13
15
9
11
13
15
9
11
13
15
9
11
13
15
9
11
13
15
500
600
750
900
1100
2.
Cross-arm
length
a, b, c
m
0.95
1.20
1.45
1.60
art. 69.1
exceptional
load
EXCAVATION PERIMETER EXCAVATION PERIMETER
1.5
1.1
2.6xW
Nominal load for ∑ Vz = 10.6kN
Rx (Ry=0)
Ry (Rx=0)
art. load 68.1b
art. load 68.1c
kN
6.8
3.7
6.5
2.9
6.7
3.4
6.3
2.6
6.4
3.0
5.9
2.2
6.1
2.6
5.5
1.6
5.7
2.0
5.0
1.3
Admissible load on the tower peak:
Hy
Vz
art. 69.1
art. 68.1a, 69.1.
kN
5.2
11.0
4.4
8.9
3.8
6.3
2.7
5.2
Nominal
tower
height
m
Tower
weight
kg
part
L
cm
9
320
138
11
425
144
13
490
111
15
620
144
Foundation
TOWER FOUNDATION
11
NAL2
20 (35) kV
9, 11, 13, 15 m
Rx, Ry
Soil
σdop
kN/m2
120 + PV
150
200 + PV
250
≥500
120 + PV
150
200 + PV
250
≥500
120 + PV
150
200 + PV
250
≥500
120 + PV
150
200 + PV
250
≥500
Foundation
dimensions
A
T
cm
80
210
80
180
80
190
80
160
80
150
80
220
80
190
80
200
80
170
80
150
100
220
100
190
100
200
100
170
100
150
100
230
100
200
100
210
100
180
100
150
DALEKOVOD - PROJEKT
Tower type mark
Nominal voltage
Nominal tower height(s)
Nominal load
(allowed horizontal load Hx and Hy reduced to
the tower top - over the 8.5 m section)
Basic load safety factor
Exceptional load safety factor
Wind force on the structure
SUSPENSION TOWER NAP2
SIDE X
SIDE Y
1.
Basic wind
load - W
Nominal
tower height
N/m2
m
9
11
13
15
9
11
13
15
9
11
13
15
9
11
13
15
9
11
13
15
500
600
750
900
1100
2.
Cross-arm
length
a, b, c
m
0.95
1.20
1.45
1.60
art. 69.1
exceptional
load
EXCAVATION PERIMETER EXCAVATION PERIMETER
1.5
1.1
2.6xW
Nominal load for ∑ Vz = 8kN
Rx (Ry=0)
Ry (Rx=0)
art. load 68.1b
art. load 68.1c
kN
8.2
7.0
10.7
6.9
5.5
7.9
6.8
10.5
6.5
5.1
7.5
6.2
10.3
5.8
4.3
7.0
5.5
10.1
5.0
3.4
6.1
4.7
9.8
4.1
2.5
Admissible load on the cross-arm top:
Hy
Vz
art. 69.1
art. 68.1a, 69.1.
kN
8.3
11.0
7.8
8.0
6.9
6.0
6.4
5.2
Nominal
tower
height
m
Tower
weight
kg
part
L
cm
9
390
124
11
575
177
13
650
101
15
785
185
Foundation
TOWER FOUNDATION
12
NAP2
20 (35) kV
9, 11, 13, 15 m
Rx, Ry
Soil
σdop
kN/m2
120 + PV
150
200 + PV
250
≥500
120 + PV
150
200 + PV
250
≥500
120 + PV
150
200 + PV
250
≥500
120 + PV
150
200 + PV
250
≥500
Foundation
dimensions
A
T
cm
100
220
100
190
100
200
100
170
100
160
120
220
120
190
120
200
120
170
120
160
120
230
120
200
120
210
120
170
120
160
120
240
120
200
120
220
120
180
120
160
STEEL LATTICE TOWERS FOR 10, 20 AND 35 kV TRANSMISSION LINES
Tower type mark
Nominal voltage
Nominal tower height(s)
TENSION TOWER ZAE2
SIDE X
ZAE2
20 (35) kV
9, 11, 13, 15 m
(17, 19, 21 m)
R=Rx + Ry
Nominal load
(allowed horizontal load Hx and Hy reduced to
the tower top - over the 8.8 m section)
Basic load safety factor
Exceptional load safety factor
Wind force on the structure
TOWER PEAK
PLAN VIEW
1.5
1.1
2.6xW
Allowed load
1. Reduced to
the tower top
Load
situation
R=Rx+Ry
2. At the point of action on the structure
Vertical load
∑Vz
Horizontal load for torque
(kNm)
kN
20
68.2
kN
11.3
10.2
11.0
9.0
10.3
11.9
8
Mt=0
∑Hx ∑Hy
kN
19.5 19.5
15.0 19.5
17.5 19.5
19.5 14.0
19.5 17.0
19.5 19.5
69.2
Exceptional
15.5
20.0
Mt=8.6
9.0
9.0
Art.
a
b
68.1
c
Cross-arm
length
a, b, c
m
0.95
1.20
1.45
1.60
8
8
Mt=5.2
∑Hx ∑Hy
kN
11.5 11.5
8.0
11.5
9.0
11.5
11.5
7.5
11.5
8.5
11.5 11.5
Mt=10.7
7.6
7.6
Basic wind
load - W
N/m2
1100
Wx
600
1100
Wy
600
-
3. Allowed vertical load Vz on the cross-arm for:
Hy=0 kN
Hy=5.3 kN
Hy=7.7 kN
Hy=10.42 kN
kN
11.8
8.9
6.3
5.2
kN
11.3
8.3
6.1
5.2
kN
11.0
8.0
6.0
5.2
kN
10.7
7.7
5.7
4.7
EXCAVATION PERIMETER EXCAVATION PERIMETER
The tower can be used only if all three conditions for allowed load (1, 2 and 3) are
satisfied
Nominal
tower
height
m
Tower
weight
kg
Foundation
part
L
cm
9
390
112
11
500
168
13
585
106
15
715
183
TOWER FOUNDATION
13
Soil
σdop
kN/m2
120 + PV
150
200 + PV
250
≥500
120 + PV
150
200 + PV
250
≥500
120 + PV
150
200 + PV
250
≥500
120 + PV
150
200 + PV
250
≥500
Foundation
dimensions
A
T
cm
140
200
120
180
140
180
120
160
120
160
140
220
140
180
140
200
140
160
140
160
160
220
140
190
140
210
140
170
140
160
160
230
160
190
160
200
160
170
160
160
DALEKOVOD - PROJEKT
Tower type mark
Nominal voltage
Nominal tower height(s)
TENSION TOWER ZAH2
SIDE X
ZAH2
20 (35) kV
9, 11, 13, 15 m
(17, 19, 21 m)
R=Rx + Ry
Nominal load
(allowed horizontal load Hx and Hy reduced to
the tower top - over the 8.8 m section)
Basic load safety factor
Exceptional load safety factor
Wind force on the structure
TOWER PEAK
PLAN VIEW
1.5
1.1
2.6xW
Allowed load
Load
situation
1. Reduced to
the tower top
R=Rx+Ry
Art.
68.2
kN
17.6
17.0
17.8
16.2
17.3
18.9
69.2
exceptional
24.2
a
b
68.1
c
Cross-arm
length
a, b, c
m
0.95
1.20
1.45
1.60
2. At the point of action on the structure
Vertical load
∑Vz
Horizontal load for torque
(kNm)
10.0
Mt=0
∑Hx ∑Hy
kN
28.0 28.0
26.0 28.0
27.0 28.0
28.0 25.0
28.0 26.0
28.0 28.0
Mt=7.5
∑Hx ∑Hy
kN
16.0 16.0
14.0 16.0
15.0 16.0
16.0 13.0
16.0 14.0
16.0 16.0
34.0
Mt=12.5
19.0 19.0
Mt=15.0
14.0 14.0
kN
34.0
10.0
10.0
Basic wind
load - W
N/m2
1100
Wx
600
1100
Wy
600
-
3. Allowed vertical load Vz on the cross-arm for:
Hy=0 kN
Hy=5.3 kN
Hy=7.7 kN
Hy=10.42 kN
kN
11.8
8.9
6.3
5.2
kN
11.2
8.3
6.1
5.2
kN
11.0
8.0
6.0
5.2
kN
10.7
7.7
5.7
4.7
EXCAVATION PERIMETER EXCAVATION PERIMETER
The tower can be used only if all three conditions for allowed load (1, 2 and 3) are
satisfied
Nominal
tower
height
m
Tower
weight
kg
Foundation
part
L
cm
9
570
112
11
730
168
13
860
106
15
1045
183
TOWER FOUNDATION
14
Soil
σdop
kN/m2
120 + PV
150
200 + PV
250
≥500
120 + PV
150
200 + PV
250
≥500
120 + PV
150
200 + PV
250
≥500
120 + PV
150
200 + PV
250
≥500
Foundation
dimensions
A
T
cm
140
230
120
200
140
210
120
180
120
180
140
240
140
200
140
220
140
180
140
160
160
240
160
200
160
220
160
180
140
160
160
250
160
210
160
230
160
190
160
160
STEEL LATTICE TOWERS FOR 10, 20 AND 35 kV TRANSMISSION LINES
Tower type mark
Nominal voltage
Nominal tower height(s)
TENSION TOWER ZAJ2
ZAJ2
20 (35) kV
9, 11, 13, 15 m
(17, 19, 21 m)
R=Rx + Ry
Nominal load
(allowed horizontal load Hx and Hy reduced to
the tower top - over the 8.8 m section)
Basic load safety factor
Exceptional load safety factor
Wind force on the structure
SIDE X
TOWER PEAK
PLAN VIEW
1.5
1.1
2.6xW
Allowed load
Load
situation
1. Reduced to
the tower top
R=Rx+Ry
2. At the point of action on the structure
Vertical load
∑Vz
Horizontal load for torque
(kNm)
kN
36.0
68.2
kN
26.0
23.5
25.2
22.8
24.3
27.3
12.0
Mt=0
∑Hx ∑Hy
kN
39.0 39.0
36.0 39.0
37.0 39.0
39.0 35.0
39.0 36.0
39.0 39.0
69.2
Exceptional
35.8
36.0
Mt=17
26.0 26.0
Art.
a
b
68.1
c
Cross-arm
length
a, b, c
m
0.95
1.20
1.45
1.60
12.0
12.0
Mt=7.5
∑Hx ∑Hy
kN
23.5 23.5
19.0 23.5
20.0 23.5
23.5 18.0
23.5 19.0
23.5 23.5
Mt=21.5
18.0 18.0
Basic wind
load - W
N/m2
1100
Wx
600
1100
Wy
600
-
3. Allowed vertical load Vz on the cross-arm for:
Hy=0 kN
Hy=5.3 kN
Hy=7.7 kN
Hy=10.42 kN
kN
11.8
8.9
6.3
5.2
kN
11.2
8.3
6.1
5.2
kN
11.0
8.0
6.0
5.2
kN
10.7
7.7
5.7
4.7
EXCAVATION PERIMETER EXCAVATION PERIMETER
The tower can be used only if all three conditions for allowed load (1, 2 and 3) are
satisfied
Nominal
tower
height
m
Tower
weight
kg
Foundation
part
L
cm
9
730
114
11
935
170
13
1140
106
15
1390
183
TOWER FOUNDATION
15
Soil
σdop
kN/m2
120 + PV
150
200 + PV
250
≥500
120 + PV
150
200 + PV
250
≥500
120 + PV
150
200 + PV
250
≥500
120 + PV
150
200 + PV
250
≥500
Foundation
dimensions
A
T
cm
160
240
120
220
160
210
120
200
120
170
160
250
140
220
160
230
140
200
140
170
160
260
160
220
160
240
160
200
160
170
160
280
160
230
160
250
160
210
160
170
DALEKOVOD - PROJEKT
Tower type mark
Nominal voltage
Nominal tower height(s)
TENSION TOWER ZAL2
ZAL2
20 (35) kV
9, 11, 13, 15 m
(17, 19, 21 m)
R=Rx + Ry
Nominal load
(allowed horizontal load Hx and Hy reduced to
the tower top - over the 10.45 m section)
Basic load safety factor
Exceptional load safety factor
Wind force on the structure
SIDE X
TOWER PEAK
PLAN VIEW
1.5
1.1
2.6xW
Allowed load
Load
situation
1. Reduced to
the tower top
R=Rx+Ry
Art.
68.2
kN
34.5
33.6
34.9
33.0
34.5
36.2
69.2
Exceptional
47.5
a
b
68.1
c
Cross-arm
length
a, b, c
m
0.95
1.20
1.45
1.60
2. At the point of action on the structure
Vertical load
∑Vz
Horizontal load for torque
(kNm)
14.8
Mt=0
∑Hx ∑Hy
kN
55.0 55.0
50.0 55.0
52.0 55.0
55.0 49.0
55.0 51.0
55.0 55.0
Mt=7.5
∑Hx ∑Hy
kN
35.0 35.0
30.0 35.0
31.0 35.0
35.0 29.0
35.0 30.0
35.0 35.0
46.0
Mt=22
41.0 41.0
Mt=29
26.0 26.0
kN
46.0
14.8
14.8
Basic wind
load - W
N/m2
1100
Wx
600
1100
Wy
600
-
3. Allowed vertical load Vz on the cross-arm for:
Hy=0 kN
Hy=5.3 kN
Hy=7.7 kN
Hy=10.42 kN
kN
11.8
8.9
6.3
5.2
kN
11.2
8.3
6.1
5.2
kN
11.0
8.0
6.0
5.2
kN
10.7
7.7
5.7
4.7
EXCAVATION PERIMETER EXCAVATION PERIMETER
The tower can be used only if all three conditions for allowed load (1, 2 and 3) are
satisfied
Nominal
tower
height
m
Tower
weight
kg
Foundation
part
L
cm
9
1035
130
11
1305
183
13
1485
189
15
1825
183
TOWER FOUNDATION
16
Soil
σdop
kN/m2
120 + PV
150
200 + PV
250
≥500
120 + PV
150
200 + PV
250
≥500
120 + PV
150
200 + PV
250
≥500
120 + PV
150
200 + PV
250
≥500
Foundation
Dimensions
A
T
cm
180
240
140
230
180
220
140
200
120
180
180
260
140
240
180
230
140
210
140
180
180
270
160
240
180
240
160
210
160
180
180
280
160
250
180
260
160
220
160
190
STEEL LATTICE TOWERS FOR 10, 20 AND 35 kV TRANSMISSION LINES
Tower type mark
Nominal voltage
Nominal tower height(s)
TENSION TOWER ZAM2
ZAM2
20 (35) kV
9, 11, 13, 15 m
(17, 19, 21 m)
R=Rx + Ry
Nominal load
(allowed horizontal load Hx and Hy reduced to
the tower top - over the 12.5 m section)
Basic load safety factor
Exceptional load safety factor
Wind force on the structure
SIDE X
TOWER PEAK
PLAN VIEW
1.5
1.1
2.6xW
Allowed load
1. Reduced to
the tower top
Load
situation
R=Rx+Ry
Art.
68.2
kN
45.0
41.8
44.8
41.1
44.4
47.2
69.2
Exceptional
62.0
a
b
68.1
c
Cross-arm
length
a, b, c
m
0.95
1.20
1.45
1.60
2. At the point of action on the structure
Vertical load
∑Vz
Horizontal load for torque
(kNm)
16.0
Mt=0
∑Hx ∑Hy
kN
68.0 68.0
65.0 68.0
66.0 68.0
68.0 64.0
68.0 65.0
68.0 68.0
Mt=7.5
∑Hx ∑Hy
kN
40.5 40.5
35.0 40.5
36.0 40.5
40.5 34.5
40.5 35.5
40.5 40.5
58.0
Mt=27
50.0 50.0
Mt=38
31.0 31.0
kN
58.0
16.0
16.0
Basic wind
load - W
N/m2
1100
Wx
600
1100
Wy
600
-
3. Allowed vertical load Vz on the cross-arm for:
Hy=0 kN
Hy=5.3 kN
Hy=7.7 kN
Hy=10.42 kN
kN
11.8
8.9
6.3
5.2
kN
11.2
8.3
6.1
5.2
kN
11.0
8.0
6.0
5.2
kN
10.7
7.7
5.7
4.7
The tower can be used only if all three conditions for allowed load (1, 2 and 3) are
satisfied
Nominal
tower
height
m
Tower
weight
kg
Foundation
part
L
cm
9
1260
130
11
1600
183
13
1850
189
15
2260
183
EXCAVATION PERIMETER EXCAVATION PERIMETER
TOWER FOUNDATION
17
Soil
σdop
kN/m2
120 + PV
150
200 + PV
250
≥500
120 + PV
150
200 + PV
250
≥500
120 + PV
150
200 + PV
250
≥500
120 + PV
150
200 + PV
250
≥500
Foundation
dimensions
A
T
cm
200
250
160
230
200
220
140
210
120
180
200
260
160
240
200
240
140
230
140
200
200
280
160
260
200
250
160
230
160
190
200
290
160
270
200
260
160
240
160
200
DALEKOVOD - PROJEKT
4. 3. EXAMPLE OF SELECTING AND MONITORING TOWERS FOR CERTAIN LOAD CONDITIONS
hR = section of load reduction
The resulting force reduced to the top of the tower for a specific load must be less or equal to the nominal load. Also, it
is necessary to fulfil the combined conditions including the allowed torque, sum of horizontal forces and the allowed
load on the cross-arms, depending on the length of the cross-arm. In case of higher then permitted vertical load on the
cross-arm, the cross-arm should be reinforced by stays or props.
Rx, Ry, – load reduced to the tower top
Hx, Hy, Vz, – load at the point of action on the structure
Rx = (Hx1· h1+Hx2· h2+Hx3· h3+⏐Vz2–Vz3⏐· .a) /hR
ΣHx = Hx1 + Hx2 + Hx3 ≤ dopΣHx
Ry = (Hy1· h1+Hy2· .h2+Hy3· h3) / hR
ΣHy = Hy1 + Hy2 + Hy3 ≤ dopΣHy
Rx + Ry ≤ dopR
ΣVz = Vz1 + Vz2 + Vz3 ≤ dopΣVz
MT = ⏐Hy2 - Hy3⏐· a
18
STEEL LATTICE TOWERS FOR 10, 20 AND 35 kV TRANSMISSION LINES
EXAMPLE
3 x Al/č 95/15 mm2, σ = 95 N/mm2
conductors:
ČIII 35 mm2 , σ = 240 N/mm2
earth wire:
semi-sum of adjacent spans:
aW = 200 m
weight span:
agr = 400 m
Hypothetical tower ZAJ
w = 900 N/m2
wind pressure (load):
dt = 1.6 x 0.18 √d daN/m’
additional load:
purpose of the tower on the route:
angle-tension
line route deviation angle:
α = 150°
selected head type:
JU22
Load in line with the “Regulation on Overhead Power Lines of Nominal Voltage Between 1 and 400 kV” (Official Gazette
no. 65/88, OG no. 55/96).
Vx
Vy
Vz
Zx
Zy
Zz
Sx
Sy
kN
kN
kN
kN
kN
kN
kN/m2
kN/m2
a
5.4
-
6.8
4.3
-
4.2
-
-
b
6.1
-
2.5
4.3
-
1.1
2.6 x
0.9
-
c
3.6
0.7
2.5
2.9
0.4
1.1
-
2.6 x
0.9
1.8
6.7
2.5
1.4
5.3
1.1
-
-
2.7
10.1
6.8
-
-
-
-
-
-
Load
situation art.
68.1
68.2
P.V.
N.V.
5.4
-
6.8
4.3
-
4.2
Pzu
-
-
-
2.1
8.0
4.2
Nzu
5.4
-
6.8
-
-
-
69.2
19
DALEKOVOD - PROJEKT
Reduced to the top of the tower and sum of forces:
Load situation art. 68.1.b.
Rx =[4.3x8.8+6.1x(7.1+5.4+4.55)+2.5x1.45]/8.8 = 16.6 kN
Ry = 0
R = 16.6 kN
∑Vz =1.1+3x2.5 = 8.6 kN
∑Hy = 0
∑Hx = 4.3+3x6.1 = 22.6 kN
MT = 0
Load situation art. 68.2.
Rx = (1.4x8.8+1.8x17.05+2.5x1.45)/8.8 = 5.30 kN
Ry = (5.3x8.8+6.7x17.05)/8.8= 18.30 kN
R = 23.6 kN
∑Vz = 8.6 kN
Selected:
tower ZAJ2
dop R = 27.3 kN > 23.6 kN
dop ∑Vz = 12 kN > 8.6 kN
MT = 6.7 x 1.45 = 9.7 kNm < 10.5 kNm
∑Hy = 5.3+3x6.7 = 25.4 kN < dop ∑Hy = 28.5 kN za MT = 10.5 kNm
∑Hx = 1.4+3x1.8 = 6.8 kN < dop ∑Hx = 28.5 kN za MT = 10.5 kNm
control for load situation art. 68.1.b.
∑Hx = 22.6 kN < dop ∑Hx = 36 kN
za MT = 0
Load situation art. 69.2.
MT = 10.1x1.45 = 14.7 kNm < 17 kNm
∑Hx = 4.3+2.7+2x5.4 = 17.8 kN < 26 kN za MT = 17 kNm
∑Hy = 10.1 kN < 26 kN za MT = 17 kNm
control of the vertical load on the cross-arm
Vz = 6.8 kN, Hy = 10.1 kN ≈ 10.42 kN
za ″a″ = ″b″ = 1.20 m
dop Vz = 7.7 kN > 6.8 kNm
za ″c″ = 1.45 m dop Vz = 5.7 kN < 6.8 kNm
THE LOWER CROSS-ARM IS TO BE REINFORCED BY STAYS (OR PROPS)
20
STEEL LATTICE TOWERS FOR 10, 20 AND 35 kV TRANSMISSION LINES
5. RECOMMENDED SELECTION OF TOWERS
5. 1. MOST COMMON STRUCTURES AND CROSS SECTIONS FOR NON-INSULATED CONDUCTORS
IN DIFFERENT CLIMATE CONDITIONS
The application tables define the recommended types of towers and appropriate purpose of the tower in the route, for
certain conductor cross sections and specific max. working stress, conventional shapes of tower head type and when
used in different climate conditions,. For suspension towers the allowed wind span is stated (semi-sum of the adjacent
spans), as also for the tension towers the allowed route deviation angle is present. Towers are selected based on the
most appropriate wind span relevant for the construction of the tower, and the allowed electric span.
Electric spans defined in tables refer to use of post type isolators (string 0.00m), on the adjacent towers with equal spans
of conductor suspension i.e. equal tower head type. Actual electric spans should be precisely defined and controlled
depending on the suspension equipment and head forms of adjacent towers.
The working stress of conductors does not influence the admissible wind spans for suspension tower structures. Still
it conditions the required tower height (influence on the conductor sag) and the possibility of using the tower in case
of exceptional load (influence on the breaking strength). The allowed wind spans stated for conductor suspension sets
are equal for a specific tower head type, conductor cross section and basic wind load without regard to the quantity of
the conductor working stress.
The allowed sum of vertical forces relates to vertical load of conductors and suspension equipment and electrical
devices (disconnectors, etc.) placed on the tower.
ELEMENTS DEFINED BY THE TOWER HEAD TYPE MARK
head type: G, D, J, B, T
JU, BU - with earth wire
upper cross-arm length: 1 234-
95 cm
120 cm
145 cm
160 cm
distance between upper cross-arms, i.e.
between the top and the upper cross-arm:
21
1 - 85 cm
2 - 170 cm
3 - 255 cm
4 - 340 cm
DALEKOVOD - PROJEKT
TOWER HEAD TYPE
- all measures are in centimetres
22
STEEL LATTICE TOWERS FOR 10, 20 AND 35 kV TRANSMISSION LINES
5. 2. CONDUCTOR SUSPENSION SETS
CONDUCTORS Al/č 50/8 mm2
BASIC WIND LOAD
W = 500 N/m2
Maximum conductor working stress, σ = 95 N/mm2
Conductor suspension sets
ELECTRIC SPANS (m)
HEAD TYPE
G2
G4
D11
D21
D12
D22
J11
J21
J22
B21
B22
B23
1,0
107
152
115
137
185
206
165
260
72
165
260
1,6
89
126
96
114
154
171
137
216
60
137
216
2,5
73
104
79
94
128
142
114
179
50
114
179
170
235
195
180
265
215
200
ADDITIONAL LOAD
ΣVz
(kN)
dop
ALLOWED SEMI-SUM OF ADJACENT SPANS (m)
(wind span)
tower type
8,0
NAH2*
10,6
NAL2
9
11
13
315
330
9 – 15
350
320
330
satisfies all stated electric spans
CONDUCTORS Al/č 50/8 mm2
BASIC WIND LOAD
W = 600 N/m2
Maximum conductor working stress, σ = 95 N/mm2
Conductor suspension sets
ELECTRIC SPANS (m)
HEAD TYPE
G2
G4
D11
D21
D12
D22
J11
J21
J22
B21
B22
B23
1,0
105
149
113
134
182
201
162
254
70
162
254
1,6
87
124
94
112
154
168
134
212
59
134
212
2,5
72
102
78
93
125
139
111
175
49
111
175
130
190
157
145
220
170
155
185
200
225
ADDITIONAL LOAD
ΣVz
(kN)
dop
ALLOWED SEMI-SUM OF ADJACENT SPANS (m)
(wind span)
tower type
9
11
13
8,0
NAH2*
10,6
NAL2
9 – 15
13,6
NAP2
9 – 15
250
260
270
250
satisfies all stated electric spans
satisfies all stated electric spans
23
260
430
DALEKOVOD - PROJEKT
CONDUCTORS Al/č 50/8 mm2
BASIC WIND LOAD
W = 750 N/m2
Maximum conductor working stress, σ = 95 N/mm2
Conductor suspension sets
ELECTRIC SPANS (m)
HEAD TYPE
G2
G4
D11
D21
D12
D22
J11
J21
J22
B21
B22
B23
1,0
102
146
111
131
178
197
158
249
69
158
249
1,6
85
121
92
110
148
164
132
207
57
132
207
2,5
71
100
76
91
122
136
109
172
48
109
172
130
205
100
145
115
105
165
130
115
160
180
ADDITIONAL LOAD
∑Vz
(kN)
dop
ALLOWED SEMI-SUM OF ADJACENT SPANS (m)
(wind span)
tower type
9
11
13
8,0
NAH2*
10,6
NAL2
9 – 15
13,6
NAP2
9 – 15
185
195
205
185
195
satisfies all stated electric spans
satisfies all stated electric spans
CONDUCTORS Al/č 50/8 mm2
BASIC WIND LOAD
W = 900 N/m2
335
Maximum conductor working stress, σ = 95 N/mm2
Conductor suspension sets
ELECTRIC SPANS (m)
HEAD TYPE
G2
G4
D11
D21
D12
D22
J11
J21
J22
B21
B22
B23
1,0
101
144
109
130
175
195
156
246
68
156
246
1,6
84
120
91
108
146
162
130
205
57
130
205
2,5
70
99
75
89
121
134
107
169
47
107
169
ADDITIONAL LOAD
∑Vz
(kN)
Dop
8,0
10,6
13,6
ALLOWED SEMI-SUM OF ADJACENT SPANS (m)
(wind span)
tower type
9
11
13
190
154
140
NAL2
9
11 – 15
210
NAP2
9
11 – 15
NAH2*
145
225
220
170
155
190
150
120
205
160
130
105
80
60
115
90
65
135
100
70
235
210
265
225
115
145
125
165
140
240
275
satisfies all stated electric spans
24
STEEL LATTICE TOWERS FOR 10, 20 AND 35 kV TRANSMISSION LINES
CONDUCTORS Al/č 50/8 mm2
BASIC WIND LOAD
W = 1100 N/m2
Maximum conductor working stress, σ = 95 N/mm2
Conductor suspension sets
ELECTRIC SPANS (m)
HEAD TYPE
G2
G4
D11
D21
D12
D22
J11
J21
J22
B21
B22
B23
1.0
100
142
108
128
173
192
154
243
67
154
243
1.6
83
118
90
107
144
160
128
202
56
128
202
2.5
69
98
74
88
119
132
106
167
46
106
167
ADDITIONAL LOAD
∑Vz
(kN)
dop
9
11
13
145
115
55
155
120
55
165
125
60
145
110
–
155
120
–
80
55
–
90
60
–
100
70
–
NAL2
9 – 15
160
170
180
175
155
190
165
95
45
110
50
125
65
NAP2
9 – 13
15
340
150
190
165
220
185
8,0
NAH2*
10,6
13,6
ALLOWED SEMI-SUM OF ADJACENT SPANS (m)
(wind span)
tower type
satisfies all stated electric spans
8,0
ZAE2
9 – 15
(17 – 21)**
satisfies all stated electric spans
(W = 1300 N/m2)**
195
140
225
145
10,0
ZAH2
9 – 15
(17 – 21)**
satisfies all stated electric spans
(W = 1300 N/m2)**
310
260
360
300
*
=>
Tower type NAH2 with cross-arm length 1.45 m (J21, J22, B) and 1.6 m (G4), does not satisfy the
required mechanical resistance and stability requirements in case of exceptional load i.e. in case of
conductor breaking.
**
=>
Allowed wind spans are defined for the higher wind area due to the fact that towers have over 15 m.
For the defined wind it is also necessary to use adequate electric spans.
25
DALEKOVOD - PROJEKT
CONDUCTORS Al/č 70/12 mm2
BASIC WIND LOAD
W = 500 N/m2
Maximum conductor working stress, σ = 95 N/mm2
Conductor suspension sets
ELECTRIC SPANS (m)
HEAD TYPE
G2
G4
D11
D21
D12
D22
J11
J21
J22
B21
B22
B23
1,0
110
156
119
142
155
212
170
268
74
170
268
1,6
93
132
100
119
131
179
143
226
62
143
255
2,5
77
110
83
99
109
149
120
188
52
120
188
170
145
140
190
160
150
210
175
160
ADDITIONAL LOAD
∑Vz
(kN)
dop
8,0
10,6
ALLOWED SEMI-SUM OF ADJACENT SPANS (m)
(wind span)
tower type
9
NAH2* 11
13
NAL2
260
270
9
11 – 15
285
260
270
260
235
satisfies all stated electric spans
CONDUCTORS Al/č 70/12 mm2
BASIC WIND LOAD
W = 600 N/m2
Maximum conductor working stress, σ = 95 N/mm2
Conductor suspension sets
ELECTRIC SPANS (m)
HEAD TYPE
G2
G4
D11
D21
D12
D22
J11
J21
J22
B21
B22
B23
1.0
108
153
116
138
187
207
166
262
72
166
262
1.6
91
129
98
116
157
175
140
220
61
140
220
2.5
76
107
82
97
131
146
117
184
51
117
184
280
230
220
140
115
110
155
125
115
180
140
125
330
300
160
175
210
190
ADDITIONAL LOAD
∑Vz
(kN)
dop
8,0
10,6
13,6
ALLOWED SEMI-SUM OF ADJACENT SPANS (m)
(wind span)
tower type
NAH2*
9
11
13
NAL2
9
11 – 15
NAP2
9
11 – 15
200
210
225
200
satisfies all stated electric spans
satisfies all stated electric spans
26
340
STEEL LATTICE TOWERS FOR 10, 20 AND 35 kV TRANSMISSION LINES
CONDUCTORS Al/č 70/12 mm2
BASIC WIND LOAD
W = 750 N/m2
Maximum conductor working stress, σ = 95 N/mm2
Conductor suspension sets
ELECTRIC SPANS (m)
HEAD TYPE
G2
G4
D11
D21
D12
D22
J11
J21
J22
B21
B22
B23
1,0
105
149
113
135
182
202
162
255
71
162
256
1,6
88
126
95
114
154
170
137
215
60
137
215
2,5
74
105
80
95
128
142
114
179
50
114
179
ADDITIONAL LOAD
∑Vz
(kN)
dop
8,0
10,6
13,6
ALLOWED SEMI-SUM OF ADJACENT SPANS (m)
(wind span)
tower type
NAH2*
9
11
13
NAL2
9
11 – 15
NAP2
9
11 – 15
150
160
satisfies all stated electric
spans
225
180
165
195
160
150
210
170
160
80
120
95
85
135
105
95
240
220
235
115
140
125
160
140
230
260
satisfies all stated electric spans
CONDUCTORS Al/č 70/12 mm2
BASIC WIND LOAD
W = 900 N/m2
Maximum conductor working stress, σ = 95 N/mm2
Conductor suspension sets
ELECTRIC SPANS (m)
HEAD TYPE
G2
G4
D11
D21
D12
D22
J11
J21
J22
B21
B22
B23
1,0
103
147
111
133
179
199
160
251
70
160
251
1,6
87
124
94
112
151
168
134
212
59
134
212
2,5
73
103
78
93
126
140
112
177
49
112
177
ADDITIONAL LOAD
∑Vz
(kN)
dop
ALLOWED SEMI-SUM OF ADJACENT SPANS (m)
(wind span)
tower type
9
11
13
155
125
115
165
130
120
180
140
125
155
125
100
165
130
105
85
65
50
95
75
50
110
80
55
NAL2
9
11 – 15
170
165
220
195
190
170
205
180
105
95
115
100
135
115
NAP2
9
11 – 15
satisfies all stated electric spans
190
220
8,0
ZAE2
9 – 15
(17 – 21)**
satisfies all stated electric spans
(W = 1300 N/m2)**
200
160
225
180
10,0
ZAH2
9 – 15
(17 – 21)**
8,0
10,6
13,6
NAH2*
satisfies all stated electric spans
(W = 1300 N/m2)**
27
365
295
DALEKOVOD - PROJEKT
CONDUCTORS Al/č 70/12 mm2
BASIC WIND LOAD
W = 1100 N/m2
Maximum conductor working stress, σ = 95 N/mm2
Conductor suspension sets
ELECTRIC SPANS (m)
HEAD TYPE
G2
G4
D11
D21
D12
D22
J11
J21
J22
B21
B22
B23
1,0
102
145
110
131
177
196
157
248
69
157
248
1,6
86
122
92
110
149
165
132
208
58
132
208
2,5
72
102
77
92
124
138
110
174
48
110
174
ADDITIONAL LOAD
∑Vz
(kN)
dop
8,0
9
11
13
120
90
45
125
95
45
135
105
50
120
90
–
130
95
–
65
45
–
70
50
–
80
55
–
NAL2
9
11 – 15
145
130
155
135
165
145
145
120
155
135
80
35
90
40
100
45
NAP2
9 – 13
15
155
135
175
150
160
115
180
120
270
225
295
255
NAH2*
10,6
13,6
ALLOWED SEMI-SUM OF ADJACENT SPANS (m)
(wind span)
tower type
8,0
ZAE2
9 – 15
(17 – 21)**
10,0
ZAH2
9
(11 – 21)**
satisfies all stated electric spans
satisfies all stated electric spans
(W = 1300 N/m2)**
satisfies all stated electric spans
(W = 1300 N/m2)**
290
220
140
110
*
=>
Tower type NAH2 (for all head types) and tower NAL2 with cross-arm length 1.6 m does not satisfy the
required mechanical resistance and stability requirements in case of exceptional load i.e. in case of
conductor breaking.
**
=>
Allowed wind spans are defined for the higher wind area due to the fact that towers have over 15 m. For
the defined wind it is also necessary to use adequate electric spans.
28
STEEL LATTICE TOWERS FOR 10, 20 AND 35 kV TRANSMISSION LINES
CONDUCTORS Al/č 95/15 mm2
BASIC WIND LOAD
W = 500 N/m2
Maximum conductor working stress, σ = 95 N/mm2
Conductor suspension sets
ELECTRIC SPANS (m)
HEAD TYPE
G2
G4
D11
D21
D12
D22
J11
J21
J22
B21
B22
B23
1,0
108
188
120
152
216
243
204
321
89
204
321
1,6
92
160
102
129
184
207
174
273
76
174
273
2,5
77
134
86
109
155
174
146
230
64
146
230
275
245
235
120
165
135
130
185
150
140
310
170
205
180
230
210
300
325
350
ADDITIONAL LOAD
∑Vz
(kN)
dop
8,0
10,6
13,6
ALLOWED SEMI-SUM OF ADJACENT SPANS (m)
(wind span)
tower type
NAH2*
9
11
13
NAL2*
9
11 – 15
NAP2
9
11 – 15
220
230
245
220
satisfies all stated electric spans
satisfies all stated electric spans
CONDUCTORS Al/č 95/15 mm2
BASIC WIND LOAD
W = 600 N/m2
Maximum conductor working stress, σ = 95 N/mm2
Conductor suspension sets
ELECTRIC SPANS (m)
HEAD TYPE
G2
G4
D11
D21
D12
D22
J11
J21
J22
B21
B22
B23
1,0
104
183
116
147
210
236
199
313
87
199
313
1,6
88
155
99
125
179
201
169
266
74
169
266
2,5
74
131
83
105
150
169
142
224
62
143
224
230
195
185
90
135
110
100
155
120
110
260
135
165
150
190
165
267
300
ADDITIONAL LOAD
∑Vz
(kN)
dop
8,0
ALLOWED SEMI-SUM OF ADJACENT SPANS (m)
(wind span)
tower type
NAH2*
9
11
13
220
185
175
250
205
195
180
215
185
175
NAL2*
9
11 – 15
13,6
NAP2
9 – 15
8,0
ZAE2
9 – 15
(17 – 21)**
satisfies all stated electric spans
(W = 750 N/m2)**
310
240
10,0
ZAH2
9 – 15
(17 – 21)**
satisfies all stated electric spans
(W = 750 N/m2)**
480
380
10,6
satisfies all stated electric spans
satisfies all stated electric spans
29
DALEKOVOD - PROJEKT
CONDUCTORS Al/č 95/15 mm2
BASIC WIND LOAD
W = 750 N/m2
Maximum conductor working stress, σ = 95 N/mm2
Conductor suspension sets
ELECTRIC SPANS (m)
HEAD TYPE
G2
G4
D11
D21
D12
D22
J11
J21
J22
B21
B22
B23
1,0
99
178
111
142
204
229
193
304
84
19
304
1,6
85
151
95
121
173
195
164
259
72
165
259
2,5
71
127
80
101
146
164
138
218
60
138
218
ADDITIONAL LOAD
∑Vz
(kN)
dop
ALLOWED SEMI-SUM OF ADJACENT SPANS (m)
(wind span)
tower type
9
11
13
165
140
130
180
145
135
195
155
145
165
135
130
180
145
135
90
75
70
105
80
75
115
90
80
NAL2*
9
11 – 15
190
200
235
215
205
190
225
200
100
125
110
145
125
13,6
NAP2
9 – 15
210
235
8,0
ZAE2
9 – 15
(17 – 21)**
210
170
240
195
10,0
ZAH2
9 – 15
(17 – 21)**
8,0
10,6
NAH2
satisfies all stated electric spans
satisfies all stated electric spans
(W = 900 N/m2)**
380
310
190
155
380
320
satisfies all stated electric spans
(W = 900 N/m2)**
CONDUCTORS Al/č 95/15 mm2
BASIC WIND LOAD
W = 900 N/m2
Maximum conductor working stress, σ = 95 N/mm2
Conductor suspension sets
ELECTRIC SPANS (m)
HEAD TYPE
G2
G4
D11
D21
D12
D22
J11
J21
J22
B21
B22
B23
1,0
96
174
108
138
199
224
190
299
83
190
299
1,6
82
148
92
118
170
190
161
254
70
161
254
2,5
69
125
78
99
143
160
136
214
59
136
214
ADDITIONAL LOAD
∑Vz
(kN)
dop
ALLOWED SEMI-SUM OF ADJACENT SPANS (m)
(wind span)
tower type
9
11
13
135
105
100
145
115
105
155
120
110
135
105
85
145
115
90
75
55
40
80
65
45
95
70
50
NAL2
9
11 – 15
165
150
155
190
165
165
145
175
155
90
80
100
90
116
95
13,6
NAP2
9 – 15
170
195
8,0
ZAE2
9 – 15
(17 – 21)**
170
140
195
155
10,0
ZAH2
9 – 15
(17 – 21)**
280
220
320
265
8,0
10,6
NAH2*
satisfies all stated electric spans
satisfies all stated electric spans
(W = 1100 N/m2)**
satisfies all stated electric spans
(W = 1100 N/m2)**
30
310
295
155
120
STEEL LATTICE TOWERS FOR 10, 20 AND 35 kV TRANSMISSION LINES
CONDUCTORS Al/č 95/15 mm2
BASIC WIND LOAD
W = 1100 N/m2
Maximum conductor working stress, σ = 95 N/mm2
Conductor suspension sets
ELECTRIC SPANS (m)
HEAD TYPE
G2
G4
D11
D21
D12
D22
J11
J21
J22
B21
B22
B23
1,0
94
172
106
135
195
220
187
294
81
187
294
1,6
80
146
90
115
166
187
159
250
69
159
250
2,5
67
123
76
97
140
157
134
210
58
134
210
ADDITIONAL LOAD
∑Vz
(kN)
dop
8,0
.10,6
13,6
8,0
10,0
*
ALLOWED SEMI-SUM OF ADJACENT SPANS (m)
(wind span)
tower type
9
11
13
100
80
40
110
85
40
115
90
40
–
–
–
–
–
–
55
60
–
–
–
NAL2*
9
11 – 15
125
110
135
120
145
125
125
110
135
115
70
30
75
35
85
35
NAP2
9 – 13
15
210
230
250
220
235
125
105
135
115
155
130
255
235
255
120
140
165
185
180
185
90
95
100
220
190
265
220
NAH2*
ZAE2
9 – 15
(17 – 21)**
ZAH2
9 – 15
(17 – 21)**
satisfies all stated electric
spans
(W = 1300 N/m2)**
satisfies all stated electric spans
(W = 1300 N/m2)**
=>
Tower type NAH2 (for all head forms) and tower NAL2 with cross-arm length over 1.20 m does not
satisfy the required mechanical resistance and stability requirements in case of exceptional load
i.e. in case of conductor breaking.
** =>
Allowed wind spans are defined for the higher wind area due to the fact that towers have over 15
m. For the defined wind it is also necessary to use adequate electric spans.
31
DALEKOVOD - PROJEKT
5. 3. CONDUCTOR TENSION SETS
Maximum conductor working stress, σ = 95 N/mm2
Conductor suspension sets
CONDUCTORS Al/č 95/15 mm2
TOWER HEAD TYPE
TOWER TYPE
THE PURPOSE
OF THE TOWER
IN THE TRANSMISSION LINE ROUTE
ALLOWED WIND SPANS FOR THE
STRUCTURE
(CONTROL ELECTRIC SPANS)
aw=(l1+l2)/2 (m)
G2, G4
(G1, G3)
D11, D21
(D31, D41)
ZAL2
ZAJ2
ZAL2
ZAJ2
ZAL2
Ka 90°
KR 120° – 180°
KR 145° – 180°
Ka 90°
KR 120° – 180°
KR 130° – 180°
Ka 90°
KR 120° – 180°
Ka 90° i
KR 120° – 124°
D12, D22
(D32, D42)
ZAJ2
KR 125° – 129°
KR 130° – 139°
KR 140° – 180°
ZAL2
Ka 90°
KR 120° – 180°
J11, J21
KR 130° – 134°
(J21*)
ZAJ2
KR 135° – 180°
ZAL2
Ka 90°
KR 120° – 180°
KR 125° – 129°
J22
(J22*)
ZAJ2
KR 130° – 139°
KR 140° – 180°
32
260
W (N/m2)
≤ 1100
200
320
≤ 1100
160
1100
210
≤ 900
370
≤ 1100
130
1100
180
900
230
≤ 750
160
1100
220
900
280
≤ 750
200
1100
260
≤ 900
270
≤ 1100
320
≤ 1100
165
1100
220
≤ 900
200
1100
260
≤ 900
380
≤ 1100
170
1100
185
900
240
≤ 750
210
1100
270
900
340
≤ 750
280
1100
350
≤ 900
STEEL LATTICE TOWERS FOR 10, 20 AND 35 kV TRANSMISSION LINES
Maximum conductor working stress, σ = 95 N/mm2
Conductor suspension sets
CONDUCTORS Al/č 95/15 mm2
TOWER HEAD TYPE
TOWER TYPE
THE PURPOSE
OF THE TOWER
IN THE TRANSMISSION LINE ROUTE
ALLOWED WIND SPANS FOR THE
STRUCTURE
(CONTROL ELECTRIC SPANS)
aw=(l1+l2)/2 (m)
W (N/m2)
B21
ZAM2
KR 155°-180°
230
(B31)
ZAM2
σ = 70 N/mm2
Ka 90° i
KR 120°-180°
150
ZAM2
KR 150°-180°
250
≤ 1100
130
110
ZAM2
σ = 80 N/mm2
Ka 90° i
KR 120°-180°
160
900
200
≤ 750
ZAL2
R 180°
300
≤ 1100
135
1100
175
900
220
≤ 750
170
1100
210
900
270
≤ 750
330
≤ 1100
140
1100
180
900
225
≤ 750
≤ 1100
B22
(B32)
ZAM2
B23
KR 125°-180°
ZAM2
σ = 80 N/mm2
Ka 90° i
KR 120°-180°
ZAL2
KR 165°-180°
(B33)
ZAL2
σ = 80 N/mm2
KR 125°-180°
Vertical forces must not exceed the allowed vertical forces for certain load scenarios and for specific cross-arm
lengths, as defined by the strength capacity table i.e. by the allowed load for a specific tower.
The defined wind spans allowed for the sharpest route deviation angle, is increased for other angles and can be
controlled according to the tower strength capacity table
Head types marked with * (J21*, J22*) are applied in cases when the torque at the basic load exceeds the values
from the strength capacity table. In this case the MT value relates to the length of the higher, and not lower
cross-arm.
33
DALEKOVOD - PROJEKT
6. ORDERING INFORMATION AND STRUCTURE
TAKEOVER
When place orders for towers it is necessary to state the required number of a certain type of towers, their height, as
also to required number of cross-arms.
Cross-arms are defined by a specific type of tower, by the head type and arrangement of conductors suspension on
the tower.
E.g.
For the transmission line route with suspension insulator strings, hanged over hinges, type of the head J21 and J22,
towers type NAL2 – 5 pieces and ZAE2 in the function of suspension tower – 1 pc., and the tension towers, head type
D21 and D22, tower type ZAJ2 – 2 pcs., and head type J21, tower ZAE2 – 1 pc., it is necessary to place the following
order:
Towers:
tower NAL2 – 13, 3 pcs.
tower NAL2 – 15, 2 pcs.
tower ZAE2 – 17, 2 pcs.
tower ZAJ2 – 11, 2 pcs
Konzole za nosivo zavješenje vodiča preko zastavica:
NAL2:
2 – 10 pcs.
J3 – 5 pcs.
ZAE2:
J2 – 2 pcs.
J3 – 1 pc.
Cross-arms for tension of conductors over hinges:
ZAJ2:
TOP – 2 psc.
D2 – 2 pcs.
G3 – 1 pc. (tap-off )
ZAE2:
J2 – 2 pcs.
J3 – 1 pc.
For the structure (cross-arm, application of stays or props, auxiliary equipment girder) that is not covered by the
catalogue, it is necessary to deliver the request accompanied with relevant technical documentation, i.e. description
based on which it is possible to make a proposal and prepare an offer for the elements required.
The standard corrosion protection of the structures is performed by hot dip galvanizing for normal atmospheric
conditions. Still it is also possible to deliver structures without corrosion protection or with additional protection
(painted), and this is necessary to be clearly stated when placing your order.
When taking over the structure, the client is delivered the building blueprints and documentation proving the quality
of the material, structure and corrosion protection of both the installed elements and of the structure as whole,
according to the static calculation of the tower.
34
STEEL LATTICE TOWERS FOR 10, 20 AND 35 kV TRANSMISSION LINES
DETAILS OF THE CROSS-ARM TOP
SUSPENSION TOWERS
Standard suspension sets over hinges
(delivery with note - suspension sets over hinges)
Standard suspension over the post
type insulator or shackles
ADDITIONAL PLATES FOR
DOUBLE SUSPENSION
(delivery with note
- for double suspension)
PLATES FOR SINGLE
SUSPENSION
(Delivery without notes)
TENSION TOWERS
Standard suspension over hinges
(Delivery without notes)
FOR ALL CROSS-ARMS
When placing orders for cross-arms (for suspension over “V” extension links or isolators, that is
for suspension equipment where the standard
elements are not adequate) it is necessary to additionally state the suspension mode and type, i.e.
the suspension equipment catalogue number
35
DALEKOVOD - PROJEKT
7. ASSEMBLING THE STRUCTURE
The foundation part of the structure is placed within the foundation excavation, it is centred and fixed, and then the
concrete is cast in the foundations. Further assembly is made after the concrete solidifies. The structure can be mounted
element by element (one element at the time), in parts (sections) or in one piece (complete).
Sections of the towers are composed of main legs of max. length 6m connected with diagonals, and the same section
is used for towers of different heights without requiring additional works on the structure as such. In this way the
storage (number of positions) and assembly of towers is simplified. It makes possible to very simply use them on
different locations in case the existing tower is to be disassembled, as also makes possible to use then for lower heights,
that is the foundation section can be used for both equal and for higher towers.
36
FOUNDATION SECTION
SECTION 3
FOUNDATION SECTION
SECTION 2
SECTION 2
SECTION 1
SECTION 1
STEEL LATTICE TOWERS FOR 10, 20 AND 35 kV TRANSMISSION LINES
37
DALEKOVOD - PROJEKT
8. FOUNDATIONS
l => useful length of the foundation extension
L => foundation part of the structure
d ≥ 20 cm (as required)
The foundation dimensions are recommended for each type of tower, according to the nominal load and height of the
tower in question. Foundations are calculated according to the Sulzberger method for several different characteristics
of bearing, non-aggressive and stable soil.
Soil characteristics are established according to the abovementioned Regulation for Overhead Power-lines obtained
by geo-mechanical tests used in designing transmission lines over many years of experience for:
gravel and gravel-sand soils, sandstone, flysch, etc.
free of groundwater, σdop = 250 kN/m2
with groundwater, σdop = 200 kN/m2
clay and clay-sand soils
free of groundwater, σdop = 150 kN/m2
with groundwater, σdop = 120 kN/m2
for foundations on solid rock the strength capacity, ódop > 500 kN/m2 the minimum dimensions are
conditioned by the geometry of the foundation, tower structure and method used in making the foundations.
The foundation is made for simple structure as a not-reinforced concrete block without shoe, into which is placed
the foundation part of the structure. To insure simpler installation in cases of deep foundations, the construction of
foundation extensions is proposed, in this case it is possible to use smaller profiles than the dimensions of tower main
legs. It is required to use concrete, pressure strength class C20/25, that does not lose strength by ageing.
By standard the foundation is made with crown d = 20 cm over the ground. If required (flood water, increased security
height of the conductor, construction on inclined plateau, etc.) the structure is made with appropriate heightening of
the foundations.
For soils of lower/poorer characteristics and conditions, deviating from the defaulted ones, as also for different
technology used (e.g. shallow foundations), the adequate foundations shall be recalculated. In this case it is also
necessary to take into consideration the standard length of the foundation part of the structure (L) characteristic for
each tower, or consult the manufacturer of the structure for possible manufacturing of customised foundation section
(e.g. for anchoring screws).
38
STEEL LATTICE TOWERS FOR 10, 20 AND 35 kV TRANSMISSION LINES
EXCAVATION PERIMETER
EXCAVATION PERIMETER
EXCAVATION PERIMETER
EXCAVATION PERIMETER
LOOSE SOIL AND SOILS IN
GROUND WATERS
ROCK
EXCAVATION PERIMETER
END TOWER, Ka 90º
EXCAVATION PERIMETER
EXCAVATION PERIMETER
EXCAVATION PERIMETER
ANGLE TENSION TOWER, KR
α - line route deviation angle
SOIL CHARACTERISTICS FOR THE RECOMMENDED FOUNDATION DIMENSIONS
SOIL
GRAVEL-SAND, FLYSCH,
SANDSTONE, etc.
CLAY-SAND
ROCK
GROUND WATERS
NO
YES
NO
YES
NO
min σdop (kN/m2)
150
120
250
200
>500
min γ (kN/m3)
18
9
18
9
19
min Ct (kN/cm3)
0.07
0.04
0.11
0.06
0.17
min b (degrees)
10
7
14
11
20
min mb
0.40
0.35
0.4
0.35
0.45
39
President of the Management Board: Davor Đurđević • Project Designer: Branka Podobnik • Collaborator: Tomislav Stojčević
DALEKOVOD-PROJEKT d.o.o. • design, control, consulting and engineering • 10000 Zagreb, Marijana Čavića 4
e-mail: dalekovod.projekt@dalekovod.hr • Tel: +385 1 24 11 100 - Operator • Fax: +385 1 24 52 381
www.dalekovod.com
Steel lattice towers
for 10, 20 and 35 kV transmission lines
INSTRUCTIONS FOR DEPLOYMENT OF TOWERS
Publisher: DALEKOVOD-PROJEKT d.o.o., 2010.
e-mail: dalekovod.projekt@dalekovod.hr
Ovitak engleski.indd 1
PROJEKT
3/26/10 2:20 PM