35-200 kV Compact Transmission Lines with Improved Power Transfer Capability

Transmission line capacity is characterized by the surge impedance loading. This is the largest active power that can be transmitted through power lines taking into account limiting factors. These restrictions can be divided into two types: thermal and electromagnetic. In the case of 35-220 kV overhead power lines, power transfer capability is determined by the electromagnetic properties of a line - its inductance and capacitance. Thus, surge impedance loading of power lines depends on various factors, such as a distance between phases, a distance between conductors of one phase, a configuration of phases on a tower, a cross-section of conductors, etc. This article proposes methods to increase power transfer capability of 35-220 kV transmission lines by applying new compact line designs. New methods for determining inductive reactances and capacitive conductivities of the proposed compact lines have been developed. The dependences of electrical parameters of new compact lines on their designs were analyzed using mathematical programming in Mathcad.