1. The problem statement, all variables and given/known data A single phase transmission line has 2 parallel conductors 1.5 metres apart. The diameter of each conductor being 0.5 cm. Calculate the line to neutral capacitance for a line 80 km long 2. Relevant equations CAN = 2(3.14)(permittivity)/Loge [D/r] This gives capacitance per metre Where D is the distance between conductors and r is the radius. Multiplying above answer into length of line gives capacitance 3. The attempt at a solution D = 1.5 metres = 150 cm r = radius = 0.5 / 2 = 0.25 cm Substituting in above equation I get CAN = 8.69 * 10-12 F / m Multiplying this with 80 km or 80,000 m I get 0.69 micro farad. Book answer is 3.48 micro farad I guess they've used formula for line capacitance CAB instead of line to neutral capactiance.