This article addresses issues related to voltage quality and reactive power compensation aimed at increasing the electric power supply capacity of metropolitan areas. Reactive power compensation contributes to reducing power losses, increasing the transmission capacity of the electrical network, and enabling voltage regulation through the use of compensating devices. The generation of high harmonics in traction substations leads to additional losses and voltage pulsations. At present, due to rising electricity costs, reducing operational losses has become a primary and urgent challenge requiring effective solutions. In this context, recent efforts have focused on the application of new types of rectifiers, active power filters, and inverters to reduce losses in the traction network. Reactive power compensation and active filtering of harmonic components help extend the service life of expensive equipment, provide additional active power to connect new loads, and reduce the risks of malfunctions, accidents, and energy costs. A hybrid reactive power compensator can also be employed in the metro power supply system for reactive power compensation. It enables stepwise adjustment of phase current relative to phase voltage and mitigates high-frequency distortions. As a result, the power factor is improved by reducing the phase shift between current and voltage, while also smoothing harmonic distortions. One of the most effective ways to increase voltage levels in metro traction networks is through the modernization of traction substations using 12-pulse rectifiers. The use of 12-pulse rectifiers improves the power factor of the traction substation, enhances the waveform of the input current, improves power quality, and raises the level of rectified voltage without the need for additional voltage regulation devices. This article provides an in-depth analysis of the effects of reactive power on losses in the metropolitan power supply system, highlighting key issues such as the phase shift between current and voltage and the presence of high-frequency distortions. A comparative analysis of available filters shows that active power filters are the most practical solution. It is noteworthy that the load current waveform, when high harmonics are present, can differ from the fundamental harmonic by up to 96%. When active power filters are employed, the phase current waveform is accurately corrected, resulting in an increased Current Utilization Coefficient (CUC). In this case, approximately 56% of the reactive current is compensated, and harmonic distortion is reduced to less than 1%.