The paper is dedicated to investigation of ultra-high voltage long-distance transmission lines with controlled shunt reactors installed to compensate for line parameters and with synchronous condensers to increase small signal stability. The operating conditions of a 4000 km line are considered. The effect of installation sites and capacity of synchronous condensers on transmission limits is analyzed. It is shown that using coordinated control of means of shunt compensation on ultra-long transmission lines allows to significantly increase not only the limit of transmission power, but also the level of small signal stability for these lines.