Method for determining a phase angle of a power oscillation in an electrical energy supply network , in which - a temporal profile of an electrical power is determined for a measurement point of the electrical energy supply network ; - one or more oscillation modes of a power oscillation are detected using the profile of the electrical power by analysing frequencies contained in the temporal profile of the electrical power and identifying the prevailing frequencies as frequencies belonging to the present oscillation modes; characterized in that - an artificial profile of an electrical power is calculated for the frequencies of the determined oscillation modes, which artificial profile indicates a signal profile which an oscillation process of the electrical power would ideally have with a single oscillation mode; - the artificial profile is compared with the captured temporal profile of the electrical power or with a profile derived therefrom while varying the phase angle used for the calculation by comparing the artificial profile with the captured temporal profile of the electrical power if a single oscillation mode is detected or by forming a derived profile of the electrical power for each of the detected oscillation modes if a plurality of oscillation modes are detected, which derived profile contains only the frequency of the respective oscillation mode, and comparing the artificial profile with the derived profile of the electrical power; and - that phase angle which is used to calculate the artificial profile and for which the artificial profile and the captured temporal profile or the profile determined therefrom have the smallest deviation from one another is determined as the phase angle of the power oscillation. - a temporal profile of an electrical power is determined for a measurement point of the electrical energy supply network ; - one or more oscillation modes of a power oscillation are detected using the profile of the electrical power by analysing frequencies contained in the temporal profile of the electrical power and identifying the prevailing frequencies as frequencies belonging to the present oscillation modes; - an artificial profile of an electrical power is calculated for the frequencies of the determined oscillation modes, which artificial profile indicates a signal profile which an oscillation process of the electrical power would ideally have with a single oscillation mode; - the artificial profile is compared with the captured temporal profile of the electrical power or with a profile derived therefrom while varying the phase angle used for the calculation by comparing the artificial profile with the captured temporal profile of the electrical power if a single oscillation mode is detected or by forming a derived profile of the electrical power for each of the detected oscillation modes if a plurality of oscillation modes are detected, which derived profile contains only the frequency of the respective oscillation mode, and comparing the artificial profile with the derived profile of the electrical power; and - that phase angle which is used to calculate the artificial profile and for which the artificial profile and the captured temporal profile or the profile determined therefrom have the smallest deviation from one another is determined as the phase angle of the power oscillation. <EOS>