22 Aug METALUBE’s Market Leading Overhead Conductor Grease Offers Unrivalled Corrosion Protection for Conductors
Corrosion protection is an extremely important criterion for Metallic products and their composite parts, especially where environmental accelerators enter the corrosion equation and when extended construction life is a prerequisite. Nowhere is this more critical than in overhead line conductors where multi-metal construction, extreme application temperatures, exposure to humidity, salt and acidic pollutants can make up the everyday environment.
Overhead line conductors have been used to transmit and distribute power for almost 100 years, during which time the demand for electricity has increased significantly. The requirement to upgrade existing lines, construct new transmission lines for developing areas and achieve compliance with ever evolving technical specifications poses many challenges for the Transmission and Distribution networks.
As one would expect significant advancements are continually being made in the design and use of innovative technologies and materials to meet this demand. Conventional conductors the most common of which being ACSR (Aluminium Conductor Steel Reinforced) and AAAC (All Aluminium Alloy Conductor) are now being replaced with high performance HTLS conductor types such as the GZTACSR (“Gap” type ZT Aluminium Conductor Steel Reinforced) which have the capability of increasing the line ampacity utilizing existing towers, whilst it must be noted, are operating at significantly higher temperatures.
These advancements are well tested and documented to ensure performance is achieved, however the corrosion inhibitor, as an integral part of the conductor, is now being asked to provide up to 60 years protection in extreme temperature and environmental conditions. In many instances this is being overlooked, with outdated and inappropriate specifications being adhered to.
There is a general perception that aluminium will not corrode, which is not strictly true:
· Aluminium is only as good as its oxide layer.
· If water penetrates the outer layers of a stranded conductor and there is movement between the strands, then the oxide layer can be worn off.
· This is OK if oxygen is around to keep re-creating the layer, but if the water is salty (rain within 10km of the coast, sea fogs rolling in, storms blowing sea salt laden air 30 miles inland etc) then oxygen is excluded, and an electrolytic cell is formed.
· This cell consumes the pure aluminium from the strands, so the strands become smaller and hence weaken – essentially turning to slimy powder in some cases.
· This results in loss of strength.
· If AAAC then the conductor will fail.
· If an ACSR then strength will depend on the steel core, however the conductor will overheat as the aluminium area is reduced for current carrying purposes.
For Transmission and Distribution networks globally, there is an increased risk of corrosion to aluminium in coastal regions and extreme environments. These risks can be mitigated by identifying the performance requirements to ensure the longevity of the conductor, and by integrating the use of anti-corrosive grease within the overhead line conductor. METALUBE has long been trusted as a manufacturer of high-performance grease which is able to combat conductor corrosion in the most adverse environments. For over 25 years, METALUBE’s OCG™ range of greases have been used in the manufacture of conductors around the world.
So How does OCG™ Work?
METALUBE’s OCG™ range of high-performance, non-melting, cold-applied grease is designed specifically for the protection and preservation of overhead line conductors. OCG™ technology has the proven capability to extend the life and efficiency of overhead line conductors by providing optimum anti-corrosion protection and absolute minimal oil separation when used as a composite part of the conductor.
With advancements in conductor technology and increasing adoption of GZTACSR conductor, Metalube recognises that our greases must be able to protect conductor in rising temperatures and ensure the longevity of these high-performance HTLS conductors. OCG™ deploys an advanced additive package which provides protection and thermostability from -50°C to +300°C, allowing conductors to operate at maximum performance even in the toughest environments.
METALUBE’s state of the art laboratory is constantly researching and developing new greases to meet the increasing demands placed on conductors, whilst our team of quality chemists are ensuring that each batch of OCG™ grease is extensively tested to ensure that it meets the most stringent of international standards. As a result, OCG™ can be found in conductors around the world.