Suppose you have a 3-Phase AC transmission line circuit with a phase to phase RMS voltage of 100 kV @120 degrees (100/root3 kV, phase to ground). Now alongside this line is another 100 kV RMS phase to phase 3-phase line. What is the highest RMS voltage that can exist between the near phase conductors of each circuit, assuming they are not in phase? Is it 200 kV? (I assume it is 0 if they are in phase). How is this calculated using voltage vectors? Thanks.