This paper introduces a new transmission control device, the Line Compensating Phase Angle Regulator (LCPAR), which permits simultaneous control of transmission voltage phase angle, apparent line reactance, and apparent line resistance. The device permits full utilization of the transmission line it serves with minimum loss. The paper describes a load flow model and provides an explicit comparison of the performance of the LCPAR with a more conventional phase angle regulating transformer, either with electromechanical switching or solid state switching. By permitting full utilization (up to the thermal limit) of existing or new transmission lines, the device may defer or eliminate the need for new transmission.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">></ETX>