Overhead transmission line electrical modeling characterizes a conductor by three per-unit-length parameters — resistance, inductance, and capacitance — arising respectively from ohmic power loss, the self-induced magnetic flux linkage produced by current flow, and the electric-field-driven charge separation between conductors and ground. Inductance is derived formally by applying Ampere's law to find magnetic field intensity, converting to flux density via the material's permeability, integrating flux linkage separately for the field internal and external to the conductor, and generalizing to multi-conductor systems using the constraint that current sums to zero, which yields the concepts of geometric mean distance (GMD) between conductor groups and geometric mean radius (GMR, or self-GMD) as the effective radius accounting for internal flux linkage. This is foundational theory within power system analysis, specifically the parameter modeling of transmission-line components in electrical power engineering.
Overhead transmission line electrical modeling characterizes a conductor by three per-unit-length parameters — resistance, inductance, and capacitance — arising respectively from ohmic power loss, th…