Method, device and system for monitoring power supply capacity abnormality in power grid

The invention provides a method for monitoring power supply capacity abnormality in a power grid. The method comprises the following steps: S10, periodically acquiring voltage data at monitoring points arranged at specific positions in the circuit of the power grid; S12, according to a sequence from a low monitoring point to a high monitoring point and according to a predetermined strategy, comparing the voltage data periodically acquired at each monitoring point with a preset threshold range corresponding to each monitoring point, and determining an abnormal monitoring point; S14, acquiring data at the abnormal monitoring point, and if the duration of abnormality exceeds a preset second threshold and the monitoring point is positioned on a bus of each section on the low-voltage side of a main transformer, analyzing the power supply capability abnormality according to a predetermined second strategy, and determining and recording reasons for the power supply capability abnormality. The invention further provi