SOLAR TODO delivered a 110kV double-circuit transmission line in Casablanca, Morocco using steel tubular Power Transmission Towers designed for high wind exposure and long-term mechanical reliability. Instead of lattice structures, our team supplied 120 units of non-lattice, tapered round steel tubular poles—optimized for the city’s coastal wind conditions and the project’s dense corridor constraints.
Answer Capsule (TL;DR): In Casablanca, SOLAR TODO installed 120 × 25m hot-dip galvanized Q345 tubular monopoles for a ~18km, 110kV double-circuit line (150m spans). The design follows IEC 60826 / GB 50545 for wind resilience and safe conductor support.
Project Background: Why Casablanca Needed Robust Tower Mechanics
Casablanca’s transmission corridors face a combination of operational pressure and demanding environmental conditions. In the MENA region, projects often must balance right-of-way limitations, construction scheduling, and durability under frequent wind-driven loading. For this line, the client required a structure that could reliably support heavy ACSR conductors, maintain required ground clearance, and withstand wind class conditions without excessive structural complexity.
SOLAR TODO’s solution focused on the tower itself: a steel tubular monopole engineered as a tapered round transmission pole with a galvanized corrosion protection system, built to accept insulator string brackets for ACSR 240 conductor configurations at 110kV double circuit.
Product Solution Overview: Steel Tubular Power Transmission Tower (Non-Lattice)
For this Casablanca project, SOLAR TODO supplied 120 units × 25m tapered steel tubular poles for a 110kV double-circuit line (NOT lattice, NOT FRP). Each pole is manufactured from hot-dip galvanized Q345 steel and delivered as flanged bolt sections to support efficient field assembly.
The mechanical design is tuned to the electrical and line geometry requirements:
- Phase spacing: 4m
- Ground clearance: 6m
- Insulator length: 1.5m
- Span: 150m
- Total line length: ~18km
The conductor specification used on this line is ACSR 240 with:
- Mass: 920kg/km
- Max tension: 70kN
Because wind loading is a primary driver for tower design in exposed coastal environments, the project was executed under Wind Class 4 (40 m/s, IEC 60826). This directly informs the pole geometry, connection detailing, and bracketing for insulator strings and conductors.
Engineering & Standards Compliance (IEC 60826 / GB 50545)
SOLAR TODO designed and documented the pole and accessory system to comply with:
- IEC 60826 (overhead line design criteria including wind loading assumptions)
- GB 50545 (relevant Chinese standards for overhead line structures)
While the project is in Morocco, the engineering basis ensures consistent mechanical safety margins for wind-driven loads—especially important when contractors are working with tight erection windows and limited tolerance for rework.
Deployment Design in Casablanca: How the Towers Were Built and Installed
1) Tower configuration and assembly approach
Each of the 120 towers was erected as a 25m tapered steel tubular monopole. The poles are produced with cross-arm brackets for insulator strings + ACSR conductors, providing a stable mechanical interface between the pole body and the insulator string hardware.
To accelerate installation and reduce crane time in urban-adjacent areas, the poles were delivered in flanged bolt sections. On-site, crews assembled the sections using the flanged connections, then completed alignment checks before proceeding to bracket and accessory installation.
2) Foundation system: spread_footing
The foundation package for the line used a concrete spread_footing configuration with an anchor cage. This foundation approach supports stable load transfer from the tubular pole, helping manage combined bending and overturning effects under wind class design conditions.
3) Accessories critical to safe operation
Beyond the pole body, SOLAR TODO supplied the complete mechanical accessory set required for dependable overhead line performance:
- Climbing steps (for safe maintenance access)
- Cross arm (for insulator string and conductor support geometry)
- Grounding (to support electrical safety and system grounding requirements)
- Bird guard (to reduce risk of bird-related faults and physical damage)
- Vibration damper (to mitigate conductor oscillation effects)
These accessories are not “optional extras”—they directly reduce operational risk by improving maintenance safety, reducing the probability of flashover events from external interference, and stabilizing conductor behavior under wind.
4) Line geometry and clearances
The line’s electrical/mechanical layout was coordinated with the tower design to maintain:
- Phase spacing of 4m (to support required phase separation)
- 6m ground clearance (to reduce flashover risk and ensure safe overhead clearance)
- Insulator length of 1.5m (supporting insulation distance requirements for the 110kV class)
5) Wind resilience for coastal conditions
For Casablanca’s coastal environment, the project used Wind Class 4 assumptions (40 m/s) per IEC 60826. This influenced pole stiffness and the accessory layout, especially at bracket interfaces where dynamic loads can concentrate.
Technical Specifications
- Project: 110kV Double circuit transmission line
- Location: Casablanca, Morocco (MENA) (33.57, -7.59)
- Quantity: 120 units
- Tower type: Steel tubular transmission pole (NOT lattice, NOT FRP)
- Height: 25m
- Shape: tapered round steel tubular monopole
- Material: Hot-dip galvanized Q345 steel
- Weight: ~25t per pole (1000kg/m)
- Cross arms/bracketing: cross-arm brackets for insulator strings + ACSR conductors
- Phase spacing: 4m
- Ground clearance: 6m
- Conductor: ACSR 240
- Mass: 920kg/km
- Max tension: 70kN
- Insulator length: 1.5m
- Span: 150m
- Total line length: ~18km
- Wind class: Wind Class 4 (40 m/s, IEC 60826)
- Foundation: spread_footing with concrete + anchor cage
- Accessories: climbing steps + cross arm + grounding + bird guard + vibration damper
- Standards: IEC 60826 / GB 50545
Results and Impact: What This Product Delivered
Mechanical reliability aligned with wind design
By using a 25m tapered steel tubular monopole with hot-dip galvanized Q345 steel and accessory-level damping (including vibration dampers), the installation achieved a mechanical system designed for 40 m/s wind (Wind Class 4). This is particularly relevant for Casablanca’s exposure patterns, where overhead assets must tolerate dynamic loading without compromising clearances.
Safer maintenance and reduced operational risk
The inclusion of climbing steps and a complete grounding package improved maintenance access and safety readiness. In addition, bird guards help reduce fault drivers related to wildlife contact and debris accumulation.
Consistent line geometry across ~18km
With 150m spans and ~18km total length, the standardized tower configuration supported repeatable erection across the corridor. The design maintained:
- 4m phase spacing
- 6m ground clearance
- 1.5m insulator length
This consistency reduces the probability of construction deviations that can lead to later compliance issues.
Faster field erection through modular pole sections
The flanged bolt sections approach supports efficient assembly in the field. For large deployments—120 towers in this case—modular delivery helps reduce downtime and improves schedule predictability compared with monolithic fabrication.
Related Reading
References (Authoritative Standards & Guidance)
- IEC 60826 — Overhead lines design criteria (wind and mechanical loading basis).
- GB 50545 — Standards for overhead line structures (design and construction guidance).
- IEEE Std 1313 (structural considerations context) — Reference framework for lattice/structural behavior and overhead line mechanical design concepts.
- NREL (overhead line reliability and transmission infrastructure research) — Guidance on reliability impacts and system performance considerations.
- World Bank (infrastructure environmental and resilience considerations) — Framework for building resilient power assets.
Pricing & Quotation
SOLAR TODO offers three pricing tiers for this product line: FOB Supply (equipment ex-works China), CIF Delivered (including ocean freight and insurance), and EPC Turnkey (fully installed, commissioned, with 1-year warranty). Volume discounts are available for large-scale deployments. Configure your system online for an instant estimate, or request a custom quotation from our engineering team at cinn@solartodo.com.
Frequently Asked Questions
1) Are these Power Transmission Towers lattice or FRP?
No. This Casablanca deployment uses steel tubular transmission poles that are NOT lattice and NOT FRP—specifically 25m tapered steel tubular monopoles in hot-dip galvanized Q345 steel.
2) What wind conditions were used for tower design?
The line was designed under Wind Class 4 (40 m/s) according to IEC 60826, which governs the mechanical loading assumptions for overhead line structures.
3) What conductor and electrical geometry does the tower support?
The project uses ACSR 240 (920kg/km, max tension 70kN) with 4m phase spacing, 6m ground clearance, and 1.5m insulator length for the 110kV double-circuit configuration.
4) What foundation type was installed under the poles?
The towers were installed on spread_footing foundations with concrete + anchor cage, supporting stable load transfer under combined wind and conductor forces.
Internal Links
- Product page: Power Transmission Tower
- Contact: contact us
Equipment Deployed
- 120 × 25m tapered steel tubular transmission monopoles (hot-dip galvanized Q345 steel; ~25t/pole, 1000kg/m; flanged bolt sections; cross-arm brackets for insulator strings + ACSR conductors)
- ACSR 240 conductor support hardware package (ACSR 240: 920kg/km; max tension 70kN; configured for 110kV double circuit)
- 110kV insulator string interface components (insulator length 1.5m; cross-arm geometry for phase spacing 4m)
- Spread_footing foundation system (concrete with anchor cage) for each pole
- Tower accessories kit: climbing steps + cross arm + grounding + bird guard + vibration damper