Critical switching impulse strength of phase-to-phase air insulation

A new physical approach is presented to modeling of positive leader inception and breakdown of phase-to-phase insulation in air, exposed to critical switching impulses of synchronized peaks and opposite polarity. This is a generalization of a recently published model dealing with phase-to-ground insulation. Both conductor-conductor and horizontal rod-rod configurations are discussed. The influence of interphase separation, conductor height above ground, conductor radius and relative amplitude of the negative impulse on critical insulation strength is systematically investigated. An application of the model, is a physically based prediction of air density effects on phase-to-phase leader inception and breakdown, is presented.>