Factors Affecting the Lifespan of Dry-Type Transformers

When purchasing transformers, most people focus primarily on price. Few ask how long a dry-type transformer can last or inquire about its lifespan. This is because many assume that a transformer's lifespan relies solely on maintenance and upkeep. However, other factors also play a crucial role in determining a transformer's durability, including the condition of the windings, grid usage, and load conditions. Together with transformer manufacturers, we explore the factors that affect the lifespan of dry-type transformers.

Before discussing the lifespan of dry-type transformers, let’s first understand what they are. A dry-type transformer is one in which neither the core nor the windings are immersed in oil, making it a popular choice for modern grid infrastructure. It is widely used in applications such as lighting, buildings (especially high-rise structures), airports, and ports. There are generally two types of dry-type transformers: the encapsulated type with epoxy resin, and the non-encapsulated type without it. 

When used properly, dry-type transformers can have a lifespan of around 30 years. In the past, dry-type transformer oil was in direct contact with air, allowing moisture to enter and reduce insulation, limiting the typical lifespan to around 20 years under normal operation. Today, however, modern dry-type transformers use a fully sealed structure, preventing direct contact between the oil and air. This advancement has extended the lifespan of transformers from 20 to 30 years with normal use. When operated within rated limits, a 30-year lifespan is achievable. However, overloading the grid or improper use can shorten the lifespan of a dry-type transformer. Many people pay little attention to the lifespan of dry-type transformers. This is partly because external factors in the grid affect transformer longevity, but more importantly, most transformers are replaced before reaching the end of their lifespan. 

With rapid advancements in the dry-type transformer industry, new breakthroughs in efficiency and performance emerge every four to five years. As a result, manufacturers often upgrade transformers within 20-30 years, making lifespan less of a concern for most users.