As discussed in the introduction to this book, a study of transmission insulation design results in the following specifications:

The phase-to-grounded-tower strike distance, referred to in this chapter as simply the “strike distance”

The number and location of overhead shield wires

The need for and type of supplemental grounding

The number and type of insulators and the insulator string length

The need for, rating, and location of line surge arresters

The phase-phase strike distance