Patent ID: 6892165

Claim:
A method for diagnosing the normality/abnormality of an output of an installed photovoltaic power system, comprising the steps of: comparing a reference output characteristic obtained chronologically in accordance with an installation condition of said photovoltaic power system with a measured output characteristic in said photovoltaic power system obtained during operation of the photovoltaic power system itself, said installation condition includes a topography of an installation site, meteorological conditions and configuration of the photovoltaic power system, and diagnosing the normality/abnormality of the output of said photovoltaic power system based on the comparison result, wherein said photovoltaic power system in diagnosed as normal only if said measured output characteristic is greater than a first predetermined value and less than a second predetermined value, said first and second predetermined values being based on said reference output characteristic, wherein comparisons of the reference output characteristic and the measured output characteristic are performed at different time points of a day, wherein said photovoltaic power system is diagnosed as normal if the following condition is satisfied, a base value (b) times a correction factor (v) times a lower limit diagnosis factor (r) is less than an actual measured value which is less than the base value (b) times the correction factor (v) times an upper limit diagnosis factor (s).