Insulators are used in power transmission overhead lines to provide mechanical support and electrical  isolation. They are classified on the basis of material as well as voltage levels 

There are broadly three types of insulators on the basis of dielectric material – Ceramic/Porcelain insulators, Composite/ Polymer insulators and Glass insulators. As the voltage level increases the size (length) of the insulator required is large and vice-a-versa is also true. The insulators are generally designed based on mechanical and electrical requirements considering altitude, load application, pollution level. The shape of insulators is influenced by considering electrical, mechanical requirements.

The insulators are used in transmission and distribution network, electrical traction system (railway, trolley bus, tramway etc.) telegraph and telephone lines or in equipments like Surge arresters, circuit breakers and instrument transformers.

Indian Insulator Industry is continuously keeping pace with technological advancement that is occurring globally. The domestic industry manufactures various types of insulators in all ranges for LT, HT and EHT. The industry is also manufacturing insulators for 1200 kV which is currently the highest voltage in the world.

Central power sector, state electricity boards, distribution companies, private sector power transmission companies, railways and telecom sector are all major customers for this industry. The insulator manufacturers have already supplied significant volumes of 765 kV insulators i.e. more than 4 million insulators in Indian market. In order to meet the country’s growing demand of up to 1200kV, all major domestic insulator manufacturers have also strived to build sufficient capacity of insulators. Indian manufacturers are not only catering to Indian market but it has also reached to more than 75 countries including European countries, USA, Africa and Latin America. This has proved the technological capabilities of our country to supply high quality products.

State of Industry

The Government of India has initiated various Power Sector programs to meet such huge requirement. The well-established manufacturers have doubled their production capacities over the last few years. However, the overall actual demand of the insulator is far behind the projected demand which resulted in overcapacity situation for this industry.

As compared to last year, the overall sale by volume has fallen down by 7%. The major loss of sales has been observed for Hollow Insulators of LA, CTs with over 50% decline. Pin & Post Insulator’s sales has marginally declined whereas Disc Insulators registered a moderate growth of 4%. Solid core Insulators declined by 12% however Composite Insulators grown by 11%. Insulators used in Transformers declined by 4%. Although, import of Insulators through direct imports has declined by 40%; Project Imports continued to the tune of INR 350 crore including Insulators & other components, parts & fittings etc.

Cheaper imports from China have eroded the top line in both Porcelain and Composite insulator manufacturers, despite a growth in overall transmission line network.