A method of out of step detection in electrical power network

摘要

The invention relates to method of detecting out of step presence in an electric power network. The method is based on a protection device (2, 3) having means (3) for measuring voltage and currents signals of the electric lines (1) at a local (A) and remote (B) terminals and having a computer means for data processing and calculation a frequency of current and voltage at the local terminal (A) and at the remote terminal (B) and for calculating a value of the frequency. The method further comprises the following steps: calculating a value of difference of frequency differences Δf between the local (A) and remote (B) terminals, determination criteria Crit1, Crit2, Crit3, Crit4 for out of step detection and configuration of special thresholds for each criterion by a user, determination of the presence of out of step through a logic product of the results of all criteria and automatically creating a signal for activating remedial action, triggering an alarm or passing the signal indicating the out of step detection to other protection devices.