Household photovoltaic system DC side fault diagnosis method

The invention discloses a household photovoltaic system DC side fault diagnosis method, and relates to the field of power grid operation and maintenance. Household photovoltaic system DC side fault diagnosis is mostly based on experimental conditions, a requirement for the dimension of data is too high, the accuracy is pursued blindly, and application scenes are ignored. The method comprises the following steps: finding out three normal users closest to a fault user, solving a photo-generated current value according to a single-diode model formula of a photovoltaic module, calculating a powerloss time sequence of the fault user in a single day, fitting the power loss by using a least square method, combining output characteristics of a photovoltaic array, and obtaining a fault diagnosis result according to a fitting result. According to the technical scheme, the analysis and fault diagnosis of a household photovoltaic state in one region are completed only by depending on the readingand installation informati