NGK is highly experienced in supplying a wide variety of insulator strings for EHV and UHV lines throughout the world. In designing insulator string, the following requirements shall be considered.

• Lightning and switching impulse flashover characteristics
• Contamination flashover characteristics
• Corona and RIV characteristics
• Mechanical strength of insulator string and Fatigue characteristics

NGK is fully equipped with up-to-date facilities for the full scale testing on all electrical and mechanical characteristics.
From the extensive study on the hardware for insulator assembly, NGK has large quantities of technical data applicable to the optimum design of EHV and UHV insulator strings.