Alarm method, device and system for nuclear power plant monitoring system

The invention is applicable to the field of 1000MW monitoring and provides an alarm method, device and system for nuclear power plant monitoring system. the method comprises determining the current environment change type, determining the number of changed pixel values of video monitoring images when the acquired video monitoring images are changed dynamically; searching pixel value change thresholds matched with the number of the determined changed pixel values in a preset image type library; determining the change types causing the dynamic change of the monitoring images according to search results, wherein the alarm operation is not performed when the change types causing the dynamic change of the monitoring images are identical to the current environment changing types, and the alarm operation is not performed when the change types causing the dynamic change of the monitoring images are different from the current environment changing types. By means of the alarm method, device and system, the mistaken alarm probability can be reduced.