Response of underground multiconductor cable systems to external fields illumination [and reply]

The commenters state that the paper by Han et al. (1996) appears to contain a major flaw in the mathematics occasioned by the unjustified extension of the classic formulation by Sunde (1968). The latter author had dealt with cable configurations over perfectly conducting ground planes. In such cases, the image conductors would have equal magnitudes but with prefixed negative signs to satisfy tangent E equal to zero on the ground plane. When considering cables buried in the conducting half-space, the authors simply employed the same images but with a prefixed positive sign, Such would only be true if the air-earth interface, seen from below, was acting as a perfect magnetic conductor at all relevant frequencies. Such is not the case because the induction fields penetrate into the upper space including the case when displacement currents are neglected. This means their expressions for P(S´) in their eqn. 8, and p(u,y,z) in their eqn. 13 are invalid. Any alleged agreement between theory and experiment could arise from the fact that the air-ground interface is well above the cables, But, in many cases, this would not be so. In reply the it is examined in detail how the approximation was achieved without significantly affecting the analytical accuracy