Why Replace Copper with Aluminum in Transformers, and What Are the Impacts?
Aluminum-wound transformers and copper-wound transformers are two popular types of transformers used for power transmission and distribution. Their differentiating factor is the winding material, which leads to differences in performance, cost, and usage application. Why, then, replace copper with aluminum? What are the impacts?
Why Replace Copper with Aluminum?
Cost Savings
The price of aluminum is significantly lower than that of copper. As aluminum is less expensive, the use of aluminum conductors can significantly reduce the cost of producing transformers, thereby maximizing profit margins.
Weight Reduction
Aluminum density is about one-third that of copper and hence the use of aluminum conductors can reduce the transformer’s weight. This offers real advantages in transportation and installation, especially for heavy machines.
Resource Availability
Aluminum is more common in the Earth’s crust than copper and thus more readily available. Where copper supply is limited or becomes unreliable, aluminum can be a more stable and sustainable alternative.
Improved Manufacturing Procedures
Technology in contemporary manufacturing has increasingly enhanced the performance of aluminum conductors to the extent that they can almost equal the performance of copper in some applications. Design and processing techniques optimized can compensate for some of the shortcomings of aluminum.
Market Competition
The transformer industry is highly competitive, and manufacturers must reduce expenses to remain competitive. Aluminum can be utilized in place of copper to make the products price-competitive to capture a higher market share.
Technological Advances
In recent times, the development of complimentary technologies has rendered applications based on aluminum conductors more developed. For example, particular connectors and coatings can manage issues of oxidation and connections effectively to make the product more durable and efficient.
Hazards of Aluminum Rather than Copper in Transformers
Lesser Electrical Conductivity
Aluminum conductity is merely 60% as effective as copper. That is, aluminum wires for the same area have greater resistance, dissipate more energy, and are less efficient.
Mechanical Weakness
Aluminum is less strong mechanically compared to copper and therefore more likely to get deformed or broken while being installed and in service, destabilizing and reducing the reliability of the transformer.
Oxidation Problems Reducing Lifespan
Aluminum can be readily oxidized in air and a protective layer of aluminum oxide is deposited. The layer shields against additional oxidation but increases contact resistance, causing low connections and overheating, impacting the performance and life of a transformer.
Thermal Expansion Coefficient Differences
The thermal expansion coefficient for aluminum is greater than that for copper. In regions of large temperature changes, the aluminum conductors have greater changes in dimensions, loosening connections, and hindering maintenance.
Connection Complexity
Aluminum conductors must be handled with extreme caution during mating with other materials, i.e., special connectors or coating, to prevent electrochemical corrosion and low contact. Installation and maintenance become more involved and costly.
Safety Hazards
Due to the inferior conductivity and mechanical characteristics of aluminum, it heats up excessively on overload or short circuit, and this has the potential to create safety threats such as fires.
Conclusion
Although substituting copper with aluminum in transformers provides benefits in terms of cost and weight, it also has major disadvantages. When high reliability and performance are needed in applications, copper conductors are still the best option.
