Breakdown in power lines. A two-conductor power transmission system operates at a voltage V. The radius of each line is 20 mm and the lines are separated a distance of 1 m (between centers).
(a) Calculate the maximum voltage difference between the two conductors, V allowed without causing breakdown.
(b) If the two lines have an insulation layer made of rubber of thickness 2 mm which has a breakdown voltage much higher than the breakdown voltage in air, what is the estimated maximum voltage allowed now assuming the permittivity of the insulation is close to that of air?