Real-time Power Angle Measurement based on Second-Order Generalized Integrator with Frequency-Locked Loop

The power angle of the synchronous generator is a key indicator that reflects the transient stability of the power system. The accurate measurement of the power angle is thus important to ensure the stable operation of the power system. In this paper, a real-time power angle measurement of synchronous generator is proposed, which is based on the second-order generalized integrator with frequency-locked loop (SOGI-FLL). Firstly, the terminal voltage and current of synchronous generator (SG) are collected in real-time. Secondly, the fundamental-frequency positive sequence signal is extracted from the instantaneous sampling data by using the SOGI-FLL. Then the generator vector equation is used to calculate the power angle. Meanwhile, the power angle error existing in the transient process is compensated by using the generator swing equation. The one machine infinite bus (OMIB) system is considered when building the power angle monitoring model of SG. Two scenarios under both steady state and transient state are respectively simulated with the MATLAB/Simulink. The simulation results indicate that the proposed method can enable a better real-time calculation with high accuracy for both scenarios.