With the purpose of providing capacity on the West-Siberian railway, in recent times, adjustable reactive power compensation devices have been introduced. The schematic construction and parameters of such devices on the market are significantly different. In connection with this, it is necessary to choose from the set of schemes the most effective, corresponding to specific technical and economic conditions. The article assesses the power losses in the main equipment of two devices from different manufacturers, namely static thyristor compensators of reactive power produced by "KER Holding" Kazan and "Aidis groups" Moscow, installed on the Alambay and Novaya Dubrava sectional posts of the West Siberian Iron roads. The power losses in the equipment are calculated taking into account additional losses from the influence of higher harmonic components. The analysis of the circuit design of both devices in terms of loss reduction is carried out. Dependences of power losses in their elements on the generated reactive power and the current of the thyristor-reactor group are constructed. Probabilistic functions of the distribution of the current of the titrator-reactor groups of devices are given at preset settings. The results of measurements of power consumption of devices for own needs are presented. The effect of reducing power losses in the traction network from switching devices with losses in their main equipment is compared. On the basis of the work done, the elements with the greatest losses are identified. The features of each device, affecting the power loss in the main equipment, are described. Conclusions are drawn about the effectiveness of the schemes under consideration. Methods for reducing power losses in basic equipment and consumption for energy consumption are proposed.