1. Nowadays, out-of-step oscillation is still considered as the most serious stability accident.

2. Appropriately control of generator out-of-step oscillation is an important issue of generator-network harmonization.

3. Thereinto, principle, logic and parameters setting of out-of-step protection are detailed.

4. Out-of-step splitting which is an important measure to assure safe running of power system, is the last line of defence to assure the whole power network not to collapse completely.

5. The principle and setting of out-of-step protection for three- impedor is analyzed in detail in this paper.

6. Out-of-step and oscillation phenomenon can be avoided if stepper motor starts on the optimal starting frequency, and stepper motor can attain to starting rotate speed in the most short time.

7. Therefore, the P-Q symbol method cannot only judges the out-of-step between the power systems, but also as early as identify the accurate time.

8. Based on the study of the movement of oscillation center, a criterion of determining whether the center of out-of-step will lies in the interior of the generator is proposed.

9. You may need to revise any projections that are out-of-step with these indicators.

10. This paper studies the impedance characteristics seen by loss-of-excitation protection during out-of-step after losing field of a generator as well as the impedance locus when slip frequency varies .

11. When the synchronization loss takes place, disconnecting the interface of out-of-step is considered the main solution to prevent a power system from collapse.

12. The criterion possesses the features of simple configuration and excellent adaptability. Because of its easy implementation it is a practicable method for out-of-step protection.

13. Then, it has a detail introduction for distribute location of out-of-step splitting in power system.

14. The rise of the Internet has led to a view among many users and Web companies that copyright is a relic, suited only to the needs of out-of-step corporate behemoths.

15. Under the power angle closed-loop control, the resistance capacity against load disturbance is improved and the problem of out-of-step is efficiently solved.

16. In the same time, it establishes some foundation for distribution location in power system of out-of-step splitting device.

17. This paper presents a comprehensive method based on different conditions after disturbance to avoid the problems caused by the traditional prediction for out-of-step protection.