Loss of synchronism protection system and method based on geometrical characteristics of movement locus of generator

The invention relates to a loss of synchronism protection system and a method based on geometrical characteristics of movement locus of a generator. The loss of synchronism protection system comprises an information bus 2, and a global positioning system 1, a loss of synchronism protection device 6, a generator set power-angle and angular velocity synchronously measuring unit 5, a phase angle measuring unit 3 which are all connected to the information bus 2 by a remote communication unit 4, wherein the difference of data measured by the generator set power-angle and angular velocity synchronously measuring unit 5 is used as horizontal axis, the data measured by the generator set power-angle and angular velocity synchronously measuring unit 5 is used as vertical axis so as to form a phase plane, which rapidly judges the set loss of synchronism by utilizing the actual measured movement locus of the set according to the geometrical convex and concave characteristic change of the phase locus. The invention can provide the protection for a power plant when any set is in loss of synchronism, adapts to various operation modes and failure types of the power plant and an electric power system because the loss of synchronism detection accuracy and the sensitivity of the generator are unrelated with the specific structure of the power plant, has rapid loss of synchronism detection speed and simple structure, and is easy to implement.