I.G. Bevzenko, T.R. Gazizov, A.M. Zabolotsky
For real three-wire cables the variants of modal antipodes are presented, which are the coupled lines sections with the same absolute value and opposite signs of the modal delays difference. The modal antipode section is necessary for decomposition and for the following reconstruction of a pulse. This phenomenon can cause the absence of protection devises triggering and can be used for aims of electromagnetic terrorism. For two types of cables the dependencies of difference of per unit length modal delays on relative dielectric permittivity with various geometric parameters are investigated. It is shown that for АППВ–3×6 cable the modal antipode can be made simply by its immersing in medium with relative dielectric permittivity value larger than the one of the cable isolation (for example, in the water), or by winding the isolating layer over the cable, while for ВВГп−3×1,5 cable – by change of the relative dielectric permittivity of the cable internal filling.