What is Vacuum Pressure Impregnated (VPI) Transformer and How is It Better Than the Conventional Dry-type Transformer?

Vacuum pressure impregnated (VPI) transformers are vacuum pressure impregnated with a high temperature polyester varnish. These transformers provide an impeccable mechanical and short circuit strength so as to favour a number of commercial and industrial applications. They considerably reduce the risk of explosion or dangers of fire in the industry, apart from eliminating other issues like liquid leaks in the containers. The windings of the vacuum pressure impregnated transformers are made in disks, which enables them to efficiently regulate the voltage of multiple electrical appliances.

Vacuum pressure impregnation is basically a process in which a completely wound electric apparatus rotor or stator is fully submerged in a Resin. With the help of a wet and dry vacuum and pressure cycle, the resin is constructively absorbed during the insulation system. Once they are thermally prepared, the impregnated windings tend to become a homogenous and monolithic structure. A proper vacuum pressure impregnated winding will have immaculate characteristics, and hence will corroborate for a longer time with minimal maintenance. Vacuum pressure impregnation process is much better than the traditional dry-type transformer as it includes vacuum in addition to pressure for maximum productivity, also grants suitable penetration of the varnish, a thermally-cured polymer resin, in the transformer coil. In addition, varnish used on the transformer shields the windings from environmental complications like moisture and other impurities. Its also considerably reduces the vibration of the windings, which consequently decreases the discernible noise, and further prolongs the life of the transformer. Thus, VPI transformers are ideal for commercial and industrial installations that need necessary attention to the environment along with the application of minimum flammable material.

According to the report published by Research Dive, the global vacuum pressure impregnated (VPI) transformer market is expected to generate a revenue of $2,472.0 million, growing exponentially at a CAGR of 6.2% during the forecast period 2021-2030.

What is the Reason for Impregnating Transformer Coils?

The prime motive of impregnating transformer coils is to eliminate as much air as possible form the structure and replace it with any other material like epoxy which has a remarkably better dielectric strength. Hence, transformer coils are usually impregnated to optimize the overall dielectric strength of the transformer, enhance the structural integrity of the coils and provide a much better environmental protection. Epoxy resin (VII) based on tris (hydroxyl phenyl) methane is considered to be one of the most prominent epoxy resins appropriate for high-performance applications, and hence at maximized temperatures, this resin exhibit exceptional electrical and physical properties, formulations stability, and impressive moisture resistance. Furthermore, epoxies are eminent adhesives, which has the capability to firmly bond the wires and other components of the entire structure to create a robust assembly. Another reason why transformer coils is impregnated is to minimize or eradicate the winding noise, which can appreciably be achieved with the help of epoxy that minimizes noise during various commercial and industrial operations.

The Way Ahead for Vacuum Pressure Impregnated (VPI) Transformers in the Coming Years

Rapid industrialization across the globe is expected to increase the demand for vacuum pressure impregnated transformers. In addition, growing demand for VPI transformers in numerous commercial and end-use industries around the world is expected to surge its demand, owing to the increased level of safety at an affordable price provided by the VPI transformers. However, the impact of COVID-19 has had a negative impact on the demand for vacuum pressure impregnated transformers due to the large-scale shutdown of various end-use industries during lockdowns, in order to curb the spread of the virus during the pandemic. In addition, postponement of various industrial projects further aggravated the impact on the demand for VPI transformers. But its demand is predicted to revive as soon as the restrictions are lifted and industries begin to operate in full capacity. Moreover, persistent technological advancements in VPI transformers are expected to create ample opportunities for the growth of the global vacuum pressure impregnated (VPI) transformer market in the coming years.

About the Author(s)

Princy A. J

Princy holds a bachelor’s degree in Civil Engineering from the prestigious Tamil Nadu Dr. M.G.R. University at Chennai, India. After a successful academic record, she pursued her passion for writing. A thorough professional and enthusiastic writer, she enjoys writing on various categories and advancements in the global industries. She plays an instrumental role in writing about current updates, news, blogs, and trends.