Equivalent PI circuit for zero-sequence networks of parallel transmission lines

The equivalent PI circuit for single-circuit lines is well established in the literature based on the distributed parameter line model. However, the equivalent circuit for the mutually coupled zero-sequence networks of a double-circuit line has not yet been adequately addressed. This article endeavors to derive the equivalent PI circuit for the zero-sequence networks of a double-circuit line based on the distributed parameter model. The parameters of the equivalent circuits have a closed analytical form in terms of the line parameters in per-unit length. A numerical example is provided to demonstrate the application of the proposed method.