Engineering Delivery of 161kV Overhead Transmission Line: Chirano–Wassa Project, Ghana
2026/5/10 view:
Engineering Delivery of 161kV Overhead Transmission Line: Chirano–Wassa Project, Ghana
Project Overview
The Chirano–Wassa 161kV Overhead Transmission Line Project in Ghana represents a complete engineering delivery covering design, manufacturing, installation, and commissioning of high-voltage transmission infrastructure. Executed by ZHM Metal Engineering Co., Ltd., the project connects key power nodes between Chirano and Wassa, supporting grid stability and regional power distribution.
The scope includes lattice steel towers, phase conductors, overhead ground wire (OHGW/OPGW), earthing system, and line hardware fittings, all delivered in compliance with applicable international standards and adapted to local environmental conditions in West Africa.
The line is designed as a 161kV double-circuit overhead transmission line, optimized for:
▶Electrical performance: adequate insulation coordination, corona control, and power transfer capacity
▶Mechanical reliability: wind load resistance (≈25 m/s), terrain adaptability, and long-span stability
▶Environmental conditions: tropical climate, corrosion exposure, and lightning density
Design references include IEC standards and aligned methodologies comparable to GB, ASTM, and BS specifications.
Key design elements:
▶Typical span: ~300–400 m
▶Conductor configuration: twin bundled conductor system
▶Ground wire: combined GJ steel wire and OPGW (optical fiber composite ground wire)
All towers are fabricated as galvanized lattice steel structures, designed for durability and ease of installation.
Technical highlights:
▶Steel grade: Q355 / equivalent ASTM A572 Grade 50
▶Surface treatment: hot-dip galvanization (HDG) in accordance with ISO 1461
▶Structural configuration: angle steel bolted connections
▶Load cases: normal operation, broken conductor, wind load, installation condition
Advantages:
▶Modular fabrication for efficient transport
▶High corrosion resistance in humid tropical environments
The project adopts high-performance aluminum-based conductors:
▶Phase conductor: ACSR (Aluminum Conductor Steel Reinforced) or equivalent (e.g., LGJ series)
▶Configuration: twin bundled conductors to reduce corona loss and radio interference
▶Ground wire:
▶▶GJ galvanized steel wire for shielding
▶▶OPGW integrating fiber optic communication and lightning protection
Technical considerations:
▶Sag and tension calculation (stringing chart optimization)
▶Thermal rating and ampacity
The insulation system utilizes high-strength disc insulators (glass or composite polymer) suitable for 161kV operation.
Key components:
▶Suspension insulator strings
▶Strain insulator assemblies
▶Hardware fittings: clamps, yoke plates, shackles, spacers, vibration dampers
Standards:
▶IEC 60383 / IEC 61109
▶Mechanical load rating up to 100kN class
Features:
▶High pollution performance
▶UV and aging resistance
A robust earthing system is implemented to ensure safety and lightning protection:
▶Tower footing resistance control (<10 ohms typical target)
▶Grounding electrodes: copper-clad steel rods or galvanized steel
▶Counterpoise wire where required
▶Integration with overhead ground wire system
The design enhances:
▶Lightning current dissipation
▶System protection against overvoltage
Installation works include:
▶Foundation construction (reinforced concrete pad & chimney type)
▶Tower erection using derrick or crane methods
▶Conductor stringing via tension stringing method
▶OPGW installation with fiber optic continuity testing
Quality control measures:
▶Bolt torque inspection
▶Sag-tension verification
▶Alignment and clearance checks
The project has been fully tested and commissioned, including:
▶Electrical continuity and grounding resistance tests
▶Optical fiber testing (OTDR for OPGW)
▶Line energization and trial operation
All systems have been verified to meet operational and safety requirements.
Project Value
This project demonstrates a full-scope EPC capability in high-voltage transmission line engineering, with emphasis on:
▶Integrated design-to-delivery workflow
▶Adaptation to African grid and environmental conditions
▶Compliance with international engineering standards
▶Reliable long-term operation performance
ZHM Metal Engineering Co., Ltd. continues to focus on practical engineering solutions and technical optimization in global transmission infrastructure projects.
Project Overview
The Chirano–Wassa 161kV Overhead Transmission Line Project in Ghana represents a complete engineering delivery covering design, manufacturing, installation, and commissioning of high-voltage transmission infrastructure. Executed by ZHM Metal Engineering Co., Ltd., the project connects key power nodes between Chirano and Wassa, supporting grid stability and regional power distribution.
The scope includes lattice steel towers, phase conductors, overhead ground wire (OHGW/OPGW), earthing system, and line hardware fittings, all delivered in compliance with applicable international standards and adapted to local environmental conditions in West Africa.
Engineering Scope and Technical Features
The line is designed as a 161kV double-circuit overhead transmission line, optimized for:
▶Electrical performance: adequate insulation coordination, corona control, and power transfer capacity
▶Mechanical reliability: wind load resistance (≈25 m/s), terrain adaptability, and long-span stability
▶Environmental conditions: tropical climate, corrosion exposure, and lightning density
Design references include IEC standards and aligned methodologies comparable to GB, ASTM, and BS specifications.
Key design elements:
▶Typical span: ~300–400 m
▶Conductor configuration: twin bundled conductor system
▶Ground wire: combined GJ steel wire and OPGW (optical fiber composite ground wire)
▶Tower types: suspension tower, tension tower, terminal tower
All towers are fabricated as galvanized lattice steel structures, designed for durability and ease of installation.
Technical highlights:
▶Steel grade: Q355 / equivalent ASTM A572 Grade 50
▶Surface treatment: hot-dip galvanization (HDG) in accordance with ISO 1461
▶Structural configuration: angle steel bolted connections
▶Load cases: normal operation, broken conductor, wind load, installation condition
Advantages:
▶Modular fabrication for efficient transport
▶High corrosion resistance in humid tropical environments
▶Optimized weight-to-strength ratio
The project adopts high-performance aluminum-based conductors:
▶Phase conductor: ACSR (Aluminum Conductor Steel Reinforced) or equivalent (e.g., LGJ series)
▶Configuration: twin bundled conductors to reduce corona loss and radio interference
▶Ground wire:
▶▶GJ galvanized steel wire for shielding
▶▶OPGW integrating fiber optic communication and lightning protection
Technical considerations:
▶Sag and tension calculation (stringing chart optimization)
▶Thermal rating and ampacity
▶Vibration control using dampers
The insulation system utilizes high-strength disc insulators (glass or composite polymer) suitable for 161kV operation.
Key components:
▶Suspension insulator strings
▶Strain insulator assemblies
▶Hardware fittings: clamps, yoke plates, shackles, spacers, vibration dampers
Standards:
▶IEC 60383 / IEC 61109
▶Mechanical load rating up to 100kN class
Features:
▶High pollution performance
▶UV and aging resistance
▶Reliable mechanical strength under dynamic loads
A robust earthing system is implemented to ensure safety and lightning protection:
▶Tower footing resistance control (<10 ohms typical target)
▶Grounding electrodes: copper-clad steel rods or galvanized steel
▶Counterpoise wire where required
▶Integration with overhead ground wire system
The design enhances:
▶Lightning current dissipation
▶System protection against overvoltage
▶Personnel safety
Installation works include:
▶Foundation construction (reinforced concrete pad & chimney type)
▶Tower erection using derrick or crane methods
▶Conductor stringing via tension stringing method
▶OPGW installation with fiber optic continuity testing
Quality control measures:
▶Bolt torque inspection
▶Sag-tension verification
▶Alignment and clearance checks
7. Testing and Commissioning
The project has been fully tested and commissioned, including:
▶Electrical continuity and grounding resistance tests
▶Optical fiber testing (OTDR for OPGW)
▶Line energization and trial operation
All systems have been verified to meet operational and safety requirements.
Project Value
This project demonstrates a full-scope EPC capability in high-voltage transmission line engineering, with emphasis on:
▶Integrated design-to-delivery workflow
▶Adaptation to African grid and environmental conditions
▶Compliance with international engineering standards
▶Reliable long-term operation performance
ZHM Metal Engineering Co., Ltd. continues to focus on practical engineering solutions and technical optimization in global transmission infrastructure projects.
Why ZHM Huawu Metal 161kV OHTL Transmission Line Solutions?
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| Reliable and Customized Designs | Cutting Edge Designing Process | Free Online Price System | Easy Bolt-by-number Assembly |
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| Over Two Decades of Experience | Value For Money | Unmatched in Quality and Craftmanship | Excellent Customer Service |
Would you like to see more information and images of ZHM Huawu Steel's Metal 161kV OHTL Transmission Line Solutions? Visit our Photo Gallery.
HOW CAN WE HELP YOU?
ZHM’s world-class team — together with our raw material suppliers and subcontractors — works to solve your most challenging design, engineering, farbrication or construction issues.
Contact ZHM by telephone at +86 135-8815-1981 (wechat and whatsapp) or send us your questions via email to info@zhmsteelworks.com
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