Method for online monitoring breaker

The invention relates to a method for online monitoring a breaker. The method online monitors the breaker in real time by acquiring a thermal image of the breaker and analyzing the thermal image to determine the state of the breaker. It is prevented to determine the state of the breaker by manually reading the images such that a large number of manpower resources are saved. The method comprises steps of: extracting and compensating key areas of the thermal image of the breaker; obtaining a characteristic data matrix according to calculation; performing comparison to obtain first compared result data and second compared result data; performing weighted summation and calculation on the result data in order to obtain calculated result data; and finally determining the state of the breaker. The compensation for the key areas may effectively eliminate an environmental influence on the thermal image in order that a more accurate thermal image can be acquired. Characteristic extraction is performed on the compensated thermal image to obtain the more accurate characteristic data matrix and a more accurate determined result is obtained through comparison and determination, thereby improving online monitoring reliability and further improving the reliability of a power system.