Megatro 66kv Double Circuit Light Angle Tension Tower

• Usage: Tension Tower, Angle Tower
• Conductor Circuit: Double Circuit
• Certification: ISO
• Model NO.: 66KV
• Materials: Steel
• Standard: Standard
• Style: Cable Tower
• Structure: as Per Drawings and Client Requirement
• Accessories 1: Power Fitting
• Accessories 2: Conductor and Cable
• Accessories 3: Earth Wire and Opgw
• Accessories 4: Insulator
• Accessories 5: Aviation Light
• Accessories 6: Tower Earthing Kits and Template
• Accessories 7: Razor Steel
• Accessories 8: Anti-Climbing Devices
• Accessories 9: Anti-Bird Devices
• Accessories 10: Dangerous Plate
• Accessories 11: Signal Plate
• Accessories 12: Circuit and Phase Plate
• Other Services1: Installation Guide
• Other Services2: Engineering Cost and Project Budget
• Accessories 13: Fall Arrestor
• Transport Package: Export Package by Container or Bulk Cargo
• Specification: as per drawings and client requirement
• Trademark: MEGATRO
• Origin: China
• HS Code: 7308200
• Production Capacity: 60000tons/Year

Product Description

MEGATRO 66KV double circuit light angle tension tower 
This photo refers to our 66KV double circuit transmission tower, light angle tension type, two earth wire at top tower peak, and its cross-arm only at both side of tower. This type tower design and supplied to most of Asian and pacific regions.  
This tower technical data as follow:
 1 climate condition

Description	Unit	Value
Ambient temperature (°C) average over a 24hr period
Maximum temperature	°C	32
Minimum temperature	°C	24
Maximum conductor temperature	°C	80
Every day temperature for conductor	°C	28
Temperature for maximum wind	°C	30
Wind
Maximum gust wind velocity, 3seconds sustained, probability of occurrence once in 50 yrs	m/s	50 m/sec
Wind velocity Vbi  (up to 10m height, 3 year return, Vb0  * 0.76), to be used for calculation of conductor in-span swing and suspension insulator swing angle	m/s	22
Rainfall  (average monthly, wet season ) Rainfall, mean annual	mm mm	200 1150
Humidity, monthly, min,  average, max	%	55, 85, 99
No. of thunderstorm days per year, average	-	64

2 Electrical System Data   

Nominal voltage Un	66 kV
Maximum operating voltage Us	72.5 kV
Power frequency	50 Hz
Basic insulation level design BIL (lightning impulse)	325 kVpeak
Switching impulse withstand voltage phase - earth	140 kVr.m.s.
Ratio of switching over-voltage phase-tophase and phase to ground	1.5
System highest 1-phase short-circuit current level (1s)	31.5 kA
Short circuit current for thermal stability check of the OPGW (1s)	4.3 kA
Conductor type	ACSR 381  ("Mango") AS3607 / GZ
Number of conductors per phase	1
Transmission Capacity of the Line (thermal)	50 MVA
Number and type of ground-wires	2 - OPGW24
Design creepage distance for heavy pollution as per IEC 60815	31 mm/kV (SCD); 53.7 mm/kV (USCD)
Altitude above sea level	17 - 200 m
Design Code	ASCE  10-15
Type of Soil (Normal / Black cotton)	Rock soil

2.1 Basic Conductor Characteristics:

Description	ACSR 373, Mango (AU)
Cross section
Aluminium [mm^2]	381,7  mm^2
Steel [mm^2]	49,5
Total [mm^2]	431.2 mm^2
Stranding and wire diameter
Description	ACSR 373, Mango (AU)
Aluminium[mm]	3
Steel [mm]	3
Overall diameter [mm]	27 mm
Weight [kg/km]	1440 kg/km
Minimum breaking strength	119 kN

2.2 Optical Ground wire
The towers are to be equipped with two OPGW24 cross section area of at least 70mm², equivalent in mechanical properties to ACS39.
 
The OPGW shall be based on an ACS (aluminium clad steel) wire construction. The OPGW construction shall be suitable for incorporation of a number of 24 optical fibres, as per current PPE specification.
 
The main characteristics of ACS 39/12 standard earth-wire are:
 

• Conductor diameter:                              10    mm
• Approximate ACS Sectional area:              39    mm²
• Design tensile strength:                       52,8 kN
• Mass:                                 311  kg/km

3 Line Profiles

• 1:2500              horizontally
• 1:250         vertically.

4 Materials

The materials for steel pole structure shall be as follows:

1. Rolled shapes and plates

Shall conform to the following acceptable steel grades and qualities, in accordance with EN 10025:

• • S235J
  • S355J

(or approved similar)

• • the towers will be protected by zinc coating.

 

1. Connection bolts, nuts and washers

All pole connection bolts, nuts and washers shall conform to ISO 898-1 and -2 or equivalent. The bolt classes 5.6 and/or 8.8 shall be used. Other proposed classes will have to be approved.
 

1. Locking devices

All pole bolt connections shall be provided with one flat washer and one spring washer.
 
d) bolt

Size of Bolts (mm)	Tightening Torque (Nm)
16	80 ... 100
20	140 ... 180
24	280 ... 320

5 tower type
OHL Towers 66kV Two EW Peaks
 
                       Tension tower:                               D15
                      Tower body extensions:                 STD HT, +3m, +6m
                      Leg extensions:                              STD HT, -1m, +1m
 
6 Design Spans
The following spans have been derived from the previous application of the same tower types. These design spans need to be confirmed. 

Tower type	Line Angle [°]	Nominal Design Span [m]	Max Wind Span [m]	Weight Span (max/min) [m]	Max. Phase Span [m]
Light angle  (D15)	0 - 15	325	400	650/-250	550

7 Spacing and Clearances
Internal Clearances
The positioning of the conductors and of the OPGW on the tower shall be as determined by the existing tower top geometry.
 
The minimum allowable in-span clearance between phases an between phase and earth wire / OPGW
 

Dpp	min. phase-phase clearance; for 66kV lines	2.00m
Del	min. phase-earth clearance; for 66kV lines=	1.40m

 

Clearance Case	Minimum clearance 66 kV [m]
Clearance in still air*	1.4
Clearance under moderate wind** (3 year return period)	0.8
Clearance under maximum wind (50 year return period)***	0.4

Loading cases to be observed are:

• Maximum conductor temperature
• Nominal wind load.

 

Clearance Case	Minimum clearance 66 kV [m]
Vertical  in unobstructed countryside normal ground profile  in populated area	6.5 7.0
Trees under the line (vertical) Trees beside the line (horizontal)	3.0 3.0
Residential and other buildings Line above buildings (vertical dist) Line adjacent to buildings (horiz. dist.)	8.0 3.5
Antennas, street lamps, flag poles, signs, other OHL,  other urban obstacles	2.5
Roads Crossings (vertical) to road surface Adjacent to roads (horizontal)	8.0  4.0
Playgrounds, sports areas	10.0

8 Loading Cases
The loading cases to be considered for the design of the line supports and of their foundations are normal working cases and exceptional cases, as follows:

1. Normal working cases (N):
   • transverse wind  (N1)
   • oblique (at 45°) wind (N2)

 

1. Exceptional loading cases (E):
   • broken wire cases (E1)
   • erection and maintenance (E3).

Partial Safety Factors

Effect	Safety factor	Load cases (N)	Load cases (E1)	Load case (E3)
Deadweight*	gG	1.0	1.0	1.0
Wind	gW	1.5	1.1	1.1
Conductor tension	gC	1.5	1.1	1.1
Construction/maintenance, variable loads	gP			1.5

Remark: above technical data only references for our client, we can design every type for our overseas clients.

MEGATRO is a full service engineering company with a global reputation for delivering excellence and innovation in power transmission, transformation, distribution, and telecommunications systems. Our MEGATRO provide and design this type 66KV double circuit MGP-66STD15 tower mainly for our local Chinese client. Since 2004, MEGATRO focus mainly international market and had export many kind of transmission structures to overseas clients. MEGATRO has been manufacturing lattice transmission tower & tapered steel poles for lighting, traffic control, communication and utility applications. MEGATRO pioneered the development of transmission tower, telecom tower, substation, and other steel structure and was also at the forefront in the design of Transmission tower.


Over 10 years of experience and innovation in engineering, designing and building towers has evolved MEGATRO into its current form:

1. Full Turn-Key provider including site acquisition, engineering services, manufacturing,   field services-DAS, tech services, value added reseller and monitoring, maintenance and network ownership
2. Specialize in developing supplying and building wireless and wired networks and in-building telecommunications systems, as well as energy infrastructure
3. Single source from Design to System Integration
4. Top quality, ISO 9001 registered

A complete selection of towers including self-support, lattice steel tower, monopoles and guyed towers, form custom-designed radar towers to broadcast towers and energy infrastructure. MEGATRO carries a variety of related products including fall protection, transmission lines, antennas, obstruction lights, and accessories, and other products if client need, MEGATRO also tailored product as per client condition.
MEGATRO mainly design all kinds of towers and posts for:

1. Telecoms
2. Power transmission
3. TV and Radio Broadcast
4. Roads and City Development
5. Wind energy solution
6. Steel structure and workshop

Our complete selection of towers includes:

1. Self-supporting
2. Monopoles
3. Guyed towers
4. Custom-designed radar towers
5. Broadcast towers
6. Power transmission

MEGATRO also designs and manufactures tower related products including:

1. Fall protection
2. Antenna brackets
3. Other accessories if needed by clients

Today, with over 10 years of experience and our commitment to excellence, MEGATRO remains an industry leader in the manufacture and design of steel tubular & angular & monopole structures for all Highway, Municipal, Custom, telecom, lighting and electric Utility applications. MEGATRO has a complete staff of professional engineering personnel trained in the PLS Pole program and three different manufacturing processes for producing steel towers, poles and other supports. We utilize the latest versions of PLS-CADD, PLS-POLE, TOWER, AutoCAD and other CAD software.

The structure shall be designed according to load combinations given as per IEC 61936-1 and as illustrated below:
Normal loads
1 Dead weight load
2 Tension load
3 Erection load
4 wind load
 
Exceptional loads
1 Switching forces
2 short-circuit forces
3 Loss of conductor tension
4 Earthquake forces


Moreover, MEGATRO is fully equipped and qualified to carry out Design Engineering services which includes:
√ Overhead Transmission line steel tower & Telecom steel tower
   Basic Design and Analysis
√ Shop Erection Drawings
√ As-Built Drawings

MEGATRO performs in-house design activities specializing in electrical overhead transmission &telecom tower steel works, which include wind and earthquake loading, static analysis, stress analysis by finite element methods and fatigue. Our Engineering Department is boasting of highly qualified engineering who are conversant with international codes and standards. The work is carried out with extensive use of CAE/CAD via a large of computer network. The computer hardware & drafting software are liked to the CNC workshop equipment for downloading of information thereby eliminating error and saving valuable production time.

Besides, MEGATRO is one of the few manufactures who assemble a face of 66KV double circuit MGP-66STD15 tower. This attention to quality may not be the cheapest process but it does insure every tower meets our high standards of quality. And it helps to reduce on-site construction cost due to mismatched assemblies. After fabrication all 66KV double circuit MGP-66STD15 tower are delivered to the galvanizing facility to be Hot DIP Galvanized. Towers are processed through the facility by Caustic Cleaning, Pickling, and then Fluxing. These strict procedures insure years of maintenance free towers. MEGATRO' 66KV double circuit MGP-66STD15 tower systems can accommodate a variety of cross-arm. MEGATRO also offers a wide variety of accessories and mounts.

Other information:
Availability size: Based on the customer's requirements.
Material: Chinese material or as per clients requirement
Steel grades
Tower legs: Chinese steel Q355B, which equivalent to ASTM A572 GR50
Other webs, bracing and not stress plate and angle steel: Chinese Q235B, which equivalent to ASTM A36
Plates: Chinese steel Q355B, which equivalent to ASTM A572 GR50
Bolts: Bolt quality shall be Chinese Class 6.8 and 8.8, as per our Chinese standard, or ISO 898 standard or ASTM A394 type 0,1,2,3 requirements
The anti-theft bolts shall be Huck bolt Fasteners or approved equivalent.  The fasteners shall be manufactured from high tensile steel A242 or equivalent and hot-dip galvanized in accordance with ASTM specification A153 and A394.

Fabrication standard: Chinese Standard or other standard which client accepted
A) Dimension and tolerance for angle are according to GB/T1591-1994, similar to EN 10056-1/2
B) Hot dip galvanization in accordance with GB/T 13912-2002, which similar to ASTM A 123
C) The welding will be performance in accordance with AWS D1.1 or CWB standard
D) All fastener galvanization conform to ASTM A153 requirements.

Package: Both parties discuss before delivery
Port of Loading: Qingdao Port
Lead Time: One month or based on the customer's needs ( for time being our capacity about 5000 tons one month, and can meet client requirements)
Minimum order: 1 set


General Fabrication Requirements
Here is general fabrication requirements for our transmission tower; however, both parties must discuss all drawings and confirm all shop drawings, technical specification, and which standard to conform.
Before mass production, we must received all signed approved shop drawings and technical documents from our client.

Our Fabrication shall be in strict accordance with detail Drawings prepared by the Contractor and approved by the Engineer.  Fabrication shall begin after the approval of the shop assembly and tests.
      
Shearing
      
Shearing and cutting shall be performed carefully and all portions of the work which will be exposed to view after completion shall be finished neatly.  Manually guided cutting torches shall not be used.

All material over 13 (or 12) mm thick shall be cold sawn or machine flame cut.
Cropping or shearing shall be allowed for material thickness of 13 mm or less.
Flame cutting of high yield steel shall be preceded by a slight preheat operation by passing the cutting flame over the part to be cut.
All flame-cut edges shall be ground clean.
      
Bending

Bending shall be carried out in such a manner as to avoid indentation and surface damage. All bending over 5^o, or high yield steel, shall be performed while the material is hot.

Welding

No welding shall be done unless prior approval has been obtained from the Engineer.
Welding shall not be allowed at tower attachment points for conductor, shield-wire, insulators or associated assemblies or brackets.

Sub-punching

All holes in structural steel less than 10 mm thickness may be punched to full size unless otherwise noted on the approved Drawings.  Holes shown on the Drawings as drilled holes and all holes in structural steel 10 mm or more in thickness and tension members of cross-arms shall be drilled or sub-punched and reamed.

All holes shall be clean cut and without torn or ragged edges.  All burrs resulting from reaming or drilling shall be removed.  All holes shall be cylindrical and perpendicular to the member.

Where necessary to avoid distortion of the holes, holes close to the points of bends shall be made after bending.

Punching

For punching to full size, the diameter of the punch shall be 1.0 mm larger than the nominal diameter of the bolt, and the diameter of the die shall not be more than 1.5mm larger than the diameter of the punch. For sub-punching, the diameter of the punch shall be 4 mm smaller than the nominal diameter of the bolt, and the diameter of the die shall be not more than 2 mm larger than the diameter of the punch.  Sub-punching for reamed work shall be such that after reaming no punch surface shall appear in the periphery of the hole.

Hole Size

Where holes are reamed or drilled, the diameter of the finished hole shall be not greater than the nominal diameter of the bolt plus 1.0 mm.


Accuracy

All holes shall be spaced accurately in accordance with the Drawings and shall be located on the gauge lines.

The maximum allowable variation in hole spacing from that indicated on the Drawings for all bolt holes shall be 0.8 mm.

Fabrication Tolerances

A specification for tolerances shall be submitted for approval by the Engineer prior to commencement of fabrication.

Bolt List

A complete list of bolts showing their lengths and the members, which they are to connect shall be given on the erection diagrams.

Locking Devices

Locking devices for tower bolts will not be required, but point punching shall be performed.

Anti-theft Fasteners
      
Appropriate anti-theft fasteners for example Huck-bolting shall be applied on all the towers up to the level of anti-climbing devices, to prevent theft of tower members.
Piece Marks

All pieces shall be stamped before galvanizing with the piece marks shown on the erection Drawings, with the marking not less than 20 mm high placed in the same relative location on all pieces.  The marking shall be plainly visible after galvanizing.

Galvanizing

All material shall be hot-dip galvanized after fabrication in accordance with the latest revision of GB/T 13912-2002 or ASTM Specification A 123.

Material that has been rejected because of bare spots or other coating defects shall either be stripped and re-galvanized, or the uncoated areas shall be recoated by an approved method.

All plates and shapes which have been warped by the galvanizing process shall be straightened by being re-rolled or pressed.  The material shall not be hammered or otherwise straightened in a manner that will injure the protective coating.

Approval shall be secured from the Engineer if galvanizing is done outside of the Contractor's plant.

All galvanized steelwork shall be protected against white storage stain by using an approved dichromate solution treatment immediately following galvanizing.


APPLICABLE STANDARD AND CODES
All towers manufactured and design shall be generally in accordance with latest revision of the following standards except where specifically directed otherwise.
General
IEC 60826    -  Design criteria of overhead lines
IEC 60652    -  Loading tests on overhead line structures
ISO 1459    -  Metallic coatings - Protection against corrosion by Hot Dip Galvanizing
ISO 1461    -  Hot dip galvanized coatings on fabricated iron and steel articles
ISO 12944    -  Paint coatings, corrosion protection, and structural steelwork
ISO 898-1    -  Mechanical properties of fasteners. Part 1-Bolts, Screws and studs
ISO 630    -  Structural Steels - plates, wide flats, bars, sections and profiles
ISO 657    -  Hot rolled structural steel plates tolerances on dimensions and shape
ISO 7411    -  Hexagon Bolts for high strength structural bolting with large width across flats
ISO 657-5    -  Hot rolled Structural Steel Sections equal and unequal leg angles
ISO 7452    -  Hot rolled structural steel plates tolerances on dimensions and shape
BS EN 50341-1  - Overhead electrical lines exceeding AC 45kV -General Requirements
BS 8004    -  Code of Practice for Foundations
BS 8110    -  Structural use of concrete
ANSI10-97    - Design of latticed steel transmission structures
IEC 60050 (151)                         International Electro-technical Vocabulary
                                       Part 51 Electrical and Magnetic Devices
IEC 60050 (601)                      Chapter 601: Generation, transmission and distribution of electricity-General
IEC 60050 (601)                    Chapter 601: Generation, transmission and distribution of electricity-Operation
IEC 60059                              IEC standard current ratings
Chinese Standard

No	Code	DESCRIPTION
1	GB/T2694-2003	Power Transmission line Steel tower - Technical requirements for manufacturing
2	JGJ81-2002	Technical specification for welding for steel structure of building
3	GB9787-88	Measuring and allowable tolerance for hot-rolled equal angle
4	GB709-88	Measuring and allowable tolerance for hot-rolled plate and strip
5	GB/T699-1999	Quality Carbon Structural Steel
6	GB/T1591-1994	Low alloy high strength structural Steel
7	GB700-88	Carbon Structural Steel
8	GB222-84	Method of sampling steel for determination of chemical composition and permissible variations
9	GB/T228-2002	Method for Tensile testing of metals
10	GB/T232-1999	Method for Bending test of metals
11	GB/T5117-1995	Carbon Welding Rod
12	GB/T5118-1995	Low Alloy Welding Rod
13	GB/T8110-1995	Welding wires for gas shielding arc welding of carbon and low alloy steels
14	GB/T10045-2001	Carbon steel flux cored electrodes for arc welding
15	JB/T7949-1999	Weld outer dimensions for steel construction
16	GB50205-2001	Test Standard for Acceptance of Steel Structure
17	GB/T470-1997	Zinc Ingot
18	GB3098.1-2000	Mechanical properties of fasteners-Part 1:Bolts, screws and studs
19	GB3098.2-2000	Mechanical properties of fasteners-Part2: Nuts, and thread
20	GB3098.3-2000	Mechanical properties of fasteners-Part3: Fastening screw
21	GB/T5780-2000	Helical Bolts Grade C
22	GB/T41-2000	Helical Nuts Grade C
23	GB/T90-2002	Flat Washer Grade C
24	GB/T13912-2002	Metal Coating, Technical Requirement and Test Method for Hot-dip galvanized Metal Parts

American Standards:

Standard	Description
ASTM A6/A6M	Standard specification for general requirements for rolled structural steel bars, plates, and sheet piling.
ASTM - 6	-  General Requirements for delivery of Rolled Steel Plates, Shapes, sheet Piling Bars for  structural used
ASTM A36/A36-M-97a	Standard specification for Carbon structural steel
ASTM A123 / A123M-02	Standard specification for Zinc (Hot-Dip Galvanized) Coatings on iron and steel products
ASTM A143 / A143M-03	Standard Practise for Safeguarding Against Embitterment of Hot-Dip Galvanized Structural Steel Products and Procedure for Detecting Embitterment
ASTM A153/ A153M-05	Standard specification for zinc coating (Hot-Dip) on iron and steel hardware
ASTM A - 194	-   Grade for bolt
ASTM A239	Standard practice for locating the thinnest spot in a zinc (Galvanized) Coating on Iron or Steel Articles
ASTM A242	Standard specification for High-Strength Low-Alloy Structural steel
ASTM A907	Standard Specification for Carbon Steel Bolts and Studs, 60000 PSI Tensile strength
ASTM A370-06	Standard Test Methods and Definitions for Mechanical Testing of Steel Products
ASTM A325	Standard Specification for structural bolts, steel, Heat treated 120/105 ksi minimum tensile strength
ASTM A-325 or A-354	-  Galvanized hexagonal head of  connection bolt
ASTM A325-97	Standard Specification for High-strength Bolts for structural steel Joints
ASTM A384 / A384M-02	Standard Practise for Safeguarding Against Warpage and Distortion During Hot-Dip Galvanizing of Steel Assemblies.
ASTM A394-93	Standard Specification for steel Transmission Tower, Bolts, Zinc Coated and Bare
ASTMA - 563	-    Class and size of nuts
ASTMA - 572	- Chemical composition of steel
ASTM A572/A572-97c	Standard specification for High-Strength Low-Alloy Columbium-Vanadium Structural steel
ASTMA - 615	-   The anchor bolt material
ASTM A673 / A673M-07	Standard Specification for Sampling Procedure for Impact  Testing of Structural Steel
ASTM B201	Standard practice for testing Chromatic coating on Zinc and Cadmium surfaces
ASTM  E94-93	Standard Guide for Radiographic Testing
ASTM E 709-95	Standard Guide for Magnetic Particle Examination
ASCE Manual 72	-  Load testing a simple structure
ASCE 10-97	Standard Design of latticed steel transmission structures
AWS D1.1	American Welding Society D1,1/D1,1M structural Welding code- Steel
ANSI B-182-2	Bolts, nuts and washers dimensions

DIN VDE 0101                       -  Isokeraunic Level
VDE 0201                              - Climatic and environmental   conditions
CVDE 0210                           -  Minimum safety factors under    simultaneous working loads
ISO R898 Mechanical Properties of Fasteners
BS EN ISO 1461:1991 - High dip galvanized coatings on fabricated iron and steel articles. Specifications and standards
A) BS 5950: Welding Terms And Symbols
B) BS 729: Hot - Dip Galvanised Coating On Iron And Steel Articles
C) BS 2901: Filler Rods And Wires For Gas Shielded Arc Welding: Part 1 Ferritic Steels
D) BS 3692: ISO Metric Precision Hexagon Bolts, Screws And Nuts
E) BS 4360: Weldable Structural Steel
F ) BS 5135: Metal - Arc Welding Of Carbon And Carbon Manganese Steel
G) BS 5950: Part 1: Code Of Practice For Loading Latticed Tower & Masts
Part 2: Guide To The Background And Use Of Part 1"Code OF Practice For Loading"
Part 3: Strength Assessment of Members
H) DD 133 (1986): Code Of Practice For Loading Latticed Tower & Masts
I) BS 4592 (1987): Part 2: Specification For Expanded Metal Grating Panels
J) BS 4592 (1977): Code Of Practice For Protective Coating Of Iron And Steel Structure Against Corrosion
K) BS 4190: Bracing & Flanged Bolts
L) BS 4190: Rolled Steel sections, Flats & Plates

If any special requirement, we can design and discuss with client.