Restoring Transmission Towers Around the World

By: Russell Hicks, Induron Sales Representative

India Transmission TowersThe number of aged galvanized towers around the world is large and budgets are tight. The utility owners face increasing pressure to substantially upgrade transmission lines using existing infrastructure. In such cases, the use of existing and often older towers makes economic and political sense.

While the electrical industry is not very old, most towers are approaching 50 years of age without a set maintenance plan. In these aging towers, the major problems include corrosion and missing members and hardware.  The life cycle of these structures is significantly reduced by corrosion in aggressive atmospheric or polluted environments. When a tower fails, it causes outages and lost revenue, therefore, proactive maintenance is necessary to prevent tower failures. 

While zinc-rich coating systems protect corrosive substrates in the same generic manner as the original hot dip galvanization – i.e. galvanic protection, it is impossible to achieve the same level of protection with a liquid applied coating. Utility owners understand the cost prohibitive nature of abrasive blasting and the difficulty in effectively applying zinc-rich coatings systems in the field. Consequently, global utilities are relying on more proven, practical and cost-effective coatings solutions. 

The effective use of protective coatings is vital for the structures in service. With the proper protective coating system, the surface deterioration on transmission structures can be controlled. Induron Protective Coatings is offering utility owners around the world a solution to extend the life of transmission and distribution structures. 

Enhancing Overhead Line Performance on Power Transmission Structures in India

Delhi Transco Ltd. selected a 220kV tower to demonstrate the application of a protective coating. With the help of their exclusive partners in India and the SAARC, Sterlite

Power, Induron successfully rehabilitated an aged lattice leg transmission structure.

The chosen tower was the 109th tower of the Mehrowli- Bomnawli transmission line, which is more than 40 years old and located in a very dusty atmosphere. R-4 rusting was observed on the tower, with some areas completely rusted and absent of any of the original hot dip galvanization.  Induron’s Armorlux H-1212 primer, along with Induraguard 9200 were the obvious choices to address this in its condition.  

To select a suitable coating system, a thorough study based on existing steel conditions, weather and climate was required. The coating selected needed to have maximum wetting and penetration properties, such as modified linseed oil. Linseed oil has been used in tower coatings, with great success because of its excellent “wetting” properties, especially on tight rust and surfaces with old coatings remaining. 

Maintaining the structural integrity of these assets not only allows the current use to continue uninterrupted, but it also protects the structure’s ability to carry higher capacity in the future. This practice enables the utility company to save exponentially compared to the cost of additional new towers to serve the higher capacity. This effective, long-term asset allocation and financial planning was enhanced by the specification of additional layers of protection provided by Armorlux Red Primer and Induragurd 9200

Repainting the Tallest Towers in Peru

Transmission TowersLocated on the outskirts of Lima in the Andean mountain range, the tallest towers in Peru are 176 meters tall and were beginning to show signs of corrosion. Plus, exposure to extreme UV caused color loss. Consequently, the towers needed fresh coatings to comply with Peruvian air signaling regulations. 

To specify an effective coatings solution, several factors had to be taken into consideration, including product quality, resistance to sunlight (UV resistance), method of application, ease of maintenance, and the impact of the coatings on painters themselves.

To address these challenges, Induron specified Armorlux Red Primer as a primary layer to protect the aged galvanized steel from corrosion and Indurasil Silicone Alkyd as the top coat in alternating colors of Signal Orange and White. These colors are resistant to degradation by the effects of sunlight and environmental pollution. Plus, the glossy finish prevents contaminants from easily adhering to the surface of the structure. 

Because of the proximity of these tall towers to the Pacific Ocean, removal of large deposits of soluble salts and chlorides was required prior to the application of the primer and before the application of the finish coat. 

Nemetsa was the pre-approved contractor chosen for this high-profile job. They provided a qualified team of 25 to prepare and properly paint this giant structure. In the end, Induron products proved to be successful, the team managed to overcome the issue of environmental care, and the client was satisfied with the work and daily coordination. 

The Induron Protective Coatings Solution

Induron offers a value-based coatings solution that provides extreme asset protection and the maximum return on investment. Induron products, such as Induraguard 9200, Armorlux Red Primer, and Indurasil Silicone Alykd, are environmentally friendly, provide proven-protection, and streamline the application process. 

In most cases, Induron products minimize surface preparation and provide a one-coat solution that extends the life of the tower by 25 years. 

**This article was originally published in T&D India**

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