Carry out a simple insulation coordination study using the EMTP program.
1. Determine the worst-case lightning overvoltage level at the substation following a direct lightning strike to the overhead line at 1500m away from the substation. (use a 1.2/50, 32kA lightning strike.
2. Determine the most vulnerable points at the substation.
3. Using the supplied company specifications and manufacturer data ( buyers’ guide on ABB’s website), select an appropriate surge arrester(s) to ensure protection of all equipment at the substation.
4. Determine the switching overvoltage level for a simultaneous switching at the instant of peak voltage on phase A.
Write a short report summarising your results and showing typical waveforms of the computed voltages for each of the cases above, and give recommendations for overvoltage protection.