Study on Electrical Parameter Frequency of the Out-of-step Oscillation Center

Out-of-step splitting is an emergency strategy to trigger splitting devices to separate power systems into several sub-regions through capturing oscillation center before the collapse of the system. How to position the oscillation center rapidly and accurately is a key procedure in out-of-step splitting field. This paper proposes a new method to position the oscillation center based on electrical parameter frequency. Firstly the current and voltage frequency variation characteristic of out-of-step tie line is analyzed. Secondly, the electrical parameter frequency variation rules are summarizes, i.e. curves of buses voltage frequency of the oscillation center line change continuously without intersection and they have the opposite variation trend. At last, the oscillation center can be positioned accurately within half out-of-step cycle by constantly monitoring electrical parameter frequency of the transmission tie lines. The accuracy and rapidity of the method are certified by the simulation results of four machine two regional power system.