Ground fault detection device, ground fault detection method, solar energy system, and ground fault detection program

A ground fault detection method for detecting a ground fault within a photovoltaic array in a photovoltaic power generation system comprising

• photovoltaic strings configured in such a manner that a plurality of photovoltaic modules are connected in series;
• the photovoltaic array configured in such a manner that the plurality of photovoltaic strings are connected in parallel;
• and
• a load device which consumes or converts power,
• wherein the ground fault method includes:
• a disconnection step of disconnecting two or more photovoltaic strings among the plurality of photovoltaic strings from the photovoltaic power generation system by electrically separating the photovoltaic strings from each other;
• a measurement step of connecting a measurement unit to each of the plurality of photovoltaic strings to perform a predetermined measurement;
• a charging/discharging step of connecting to and charging/discharging each of the plurality of photovoltaic strings so that its potential relative to the ground is the same as the potential relative to the ground when the photovoltaic string is connected to the measurement unit;
• and
• a ground fault detection step of determining whether there is a ground fault based on a measurement value obtained in the measurement step,
• the measurement step includes performing the predetermined measurement on one photovoltaic string among the two or more photovoltaic strings disconnected in the disconnection step, as a measurement target string, and
• the charging/discharging step includes charging/discharging the other photovoltaic strings which are separate from the measurement target string and have not yet been subjected to the predetermined measurement among the two or more photovoltaic strings disconnected in the disconnection step, as charging/discharging target strings, in parallel with the measurement of the measurement target string in the measurement step.

A ground fault detection program for detecting a ground fault within a photovoltaic array in a photovoltaic power generation system comprising

• photovoltaic strings configured in such a manner that a plurality of photovoltaic modules are connected in series;
• the photovoltaic array configured in such a manner that the plurality of photovoltaic strings are connected in parallel;
• and
• a load device which consumes or converts power,
• wherein the ground fault detection program causes a computer to execute:
• a disconnection function for disconnecting two or more photovoltaic strings among the plurality of photovoltaic strings from the photovoltaic power generation system by electrically separating the photovoltaic strings from each other;
• a measurement function for connecting a measurement unit to each of the plurality of photovoltaic strings to perform a predetermined measurement;
• a charging/discharging function for connecting a charging/discharging unit to each of the plurality of photovoltaic strings and charging/discharging the photovoltaic string so that its potential relative to the ground is the same as the potential relative to the ground when the photovoltaic string is connected to the measurement unit, and
• a ground fault detection function for determining whether there is a ground fault based on a measurement value obtained through the measurement function,
• the measurement function includes performing the predetermined measurement on one photovoltaic string among the two or more photovoltaic strings disconnected through the disconnection function, as a measurement target string, and
• the charging/discharging function includes charging/discharging the other photovoltaic strings which are separate from the measurement target string and have not yet been subjected to the predetermined measurement among the two or more photovoltaic strings disconnected through the disconnection function, as charging/discharging target strings, in parallel with the measurement of the measurement target string through the measurement function.