Some complex types of damage can occur in power lines, for example, a short circuit with a wire break. This mode can occur when a wire of any phase falls to the ground (Fig. 1).

Fig. 1. Single phase short circuit with phase failure

This complex damage can be considered as a simultaneous combination of two modes: short circuit and open circuit in the same phase. In phase coordinates, the location of damage can be represented as a cascade connection of two multipoles, one of which is a direct transmission matrix of the fault location, the other is a direct transmission matrix of the breakage model (Fig. 2).

Fig. 2. Equivalent circuit of a single-phase short circuit with phase failure

The equivalent damage direct transmission matrix will be determined by the formula

__A__* _{f}* =

__A___{1}∙

__A___{2},

where __A___{1} is the direct transfer matrix of the short circuit model; matrix calculation is presented here; __A___{2} – direct transfer matrix of the break model; matrix calculation is presented here.