Analysis of a Series Tap for Half-Wavelength Transmission Lines Using Active Filters

The interconnection of distant electrical subsystems typically leads to the study of several alternatives, possibly including conventional HVAC, HVDC and half-wavelength transmission. The latter has been presented in the literature as a point-to-point very long AC line, which may represent a particular limitation in cases where supplying intermediary loads is necessary. The main goal of this paper is to describe a power electronics-based solution for this problem, the HVAC series tap. Installed along the line to drain only active power -using active filters techniques-, the tap then delivers it to a generic load connected at the inverter side. Theoretical analysis is performed to provide insight about common issues like topology, operation and control. Simulation results are shown to backup analytical data and point out advantages and disadvantages