Developing Porcelain Insulator Technology in Terms of Performance & Cost

Insulators

Electrical insulators for higher voltages started to develop once transformer technology entered the commercial level. Initially, these insulators were made of organic natural materials such as wood, cork or rubber. Soon, development saw application of inorganic materials such as porcelain and glass, which resulted in more stable insulation performance over time. Various organic materials were tested from time to time, but application did not materialize until the time the concept of a composite insulator was introduced.

Porcelain, composite and glass are all important technologies in the insulator market and their different properties have created specific niches related to application environment and boundary conditions. While porcelain still remains dominant in the HV insulator market, its leading position has come to be increasingly challenged in recent years. This has created growing pressure for improvements when it comes to both performance & cost. For example, when it comes to improving electrical performance areas driving developments can be classified under either surface problems or bulk problems in the interior of the material.

An electrically active defect is normally a contamination or crack. Among electrically active contamination in the porcelain body, iron particles larger than 10-microns are the most common. Also, quartz particles can generate microcracks that reduce electrical strength.

Ongoing developments to reduce contamination by iron particles include improved control of incoming raw materials. Another source potentially generating iron particles is erosion on iron surfaces or contamination from the industrial environment of the production plant. Ongoing trends among producers and equipment suppliers are to design, shape and operate in such a way that such contamination is eliminated, such as by sealing processed material off from the immediate environment. A long used tool for eliminating iron particles, i.e. sieving and magnetic separation, is also still under further optimization.

Quartz particles are toxic to production of porcelain insulators since the expansion coefficient of quartz is different from the refractory glass in porcelain. This results in micro-cracks that can grow slowly during every temperature change cycle. The result is ageing with continuous degradation in electrical and mechanical properties. For this reason, more production units are working to eliminate risk of quartz contamination in all incoming raw materials.

Attend the 2022 INMR WORLD CONGRESS to meet and learn from porcelain production expert, Tomas Johansson. Dr. Johansson has personally investigated and optimized some 25 different porcelain insulator production plants across the globe and over a career spanning three decades. He will review the latest technical and economic trends in the industry and explain how these are interconnected and creating new opportunities for continued improvement.