Junction box, failure diagnosis system, program, recording medium, and failure diagnosis method

摘要

PROBLEM TO BE SOLVED: To provide a connection box and the like capable of performing a diagnosis of only a solar cell string which is a diagnosis target without generating power generation loss.SOLUTION: A connection box connected to a solar cell array having a solar cell string composed of a plurality of solar cell modules connected in series comprises: a positive input signal blockage unit which is connected to a positive electrode of the solar cell string, and blocks transmission of a positive input signal applied to the solar cell string from the positive electrode for a fault diagnosis of the solar cell string or its reflection signal to the side opposite to the solar cell array; and a negative input signal blockage unit which is connected to a negative electrode of the solar cell string, and blocks transmission of a negative input signal applied to the solar cell string from the negative electrode for the fault diagnosis of the solar cell string or its reflection signal to the side opposite to the solar cell array.