Low-frequency oscillations in power systems are inherently non-linear and non-stationary processes representing a superposition of numerous rotating masses movement components having mutual influence in a power region or power center. In the case of significant power imbalance periodic low-frequency oscillations of frequency with a magnitude exceeding 0,05 Hz may arise in the power systems. These situations imply the crucial role of monitoring each generator damping capability which is determined by the adjustment of the system regulators in use. To estimate the synchronous generator capability to maintain synchronous operation under deviating load angle 0 by the value of Δθ conditions synchronizing torque ∂M/∂θ and corresponding synchronizing power ∂P/∂θ are used. The article presents techniques for defining synchronous machine load angle and corresponding synchronizing power depending on the structure of available generator performance parameters measurements as well as outlines their essential advantages and shortcomings.