Ground fault protecting apparatus and method for solar power generation and solar power generation apparatus using the apparatus and method

A protecting method for protecting a solar power generation apparatus from a ground fault comprising the steps of:

• detecting a ground fault in a solar cell array;
• upon detecting the ground fault, outputting an inverter stop signal for stopping an operation of an inverter connected between the solar cell array and a load;
• and
• after output of the inverter stop signal, outputting a disconnection signal for disconnecting the inverter from the load,
• wherein the inverter stop signal is output when the ground fault is detected for a period longer than a first predetermined time T1, and the disconnection signal is output when the ground fault is detected for a period longer than a second predetermined time T2 (>T1).

A solar power generation apparatus comprising:

• a solar cell array;
• an inverter for converting direct current power from said solar cell array to alternating current power;
• a switch for connecting/disconnecting said inverter to/from a load;
• detection means for detecting a ground fault in said solar cell array;
• and
• protection means for, when said detection means detects the ground fault, outputting an inverter stop signal for stopping an operation of said inverter and then outputting a disconnection signal for setting said switch in an open state,
• wherein said protection means outputs the inverter stop signal when the ground fault is detected for a period longer than a first predetermined time T1, and outputs the disconnection signal when the ground fault is detected for a period longer than a second predetermined time T2 (>T1).

An inverter apparatus for converting direct current power provided from a solar cell array to alternating current power comprising:

• detection means for detecting a ground fault in the solar cell array;
• and
• protection means for, when said detection means detects the ground fault, outputting a stop signal for stopping a power conversion operation of the inverter apparatus and then outputting a disconnection signal for disconnecting the inverter apparatus from a load,
• wherein said protection means outputs the stop signal when the ground fault is detected for a period longer than a first predetermined time T1, and outputs the disconnection signal when the ground fault is detected for a period longer than a second predetermined time T2 (>T1).

A computer program product comprising a computer readable medium having computer program code, for protecting a solar power generation apparatus from a ground fault in a solar battery array, said product comprising:

• detection process procedure code for detecting a ground fault in the solar battery array;
• first output process procedure code for, upon detecting the ground fault, outputting an inverter stop signal for stopping an operation of an inverter connected between the solar battery array and a load;
• and
• second output process procedure code for, after output of the inverter stop signal, outputting a disconnection signal for disconnecting the inverter from the load,
• wherein the inverter stop signal is outputted when the ground fault is detected for a period longer than a first predetermined time T1, and the disconnection signal is outputted when the ground fault is detected for a period longer than a second predetermined time T2 (>T1).

A protecting apparatus for protecting a solar power generation apparatus, said protecting apparatus comprising:

• detection means for detecting whether an output of a solar cell array is a ground fault or not;
• and
• protection means for outputting an inverter stop signal for stopping an operation of an inverter provided between the solar cell array and a load and then outputting a disconnection signal for disconnecting electrical connection between the inverter and the load based on a detection result of said detection means,
• wherein said protection means outputs the inverter stop signal when the ground fault is detected for a period longer than a first predetermined time T1, and outputs the disconnection signal when the ground fault is detected for a period longer than a second predetermined time T2, (>T1).

A solar power generation apparatus comprising:

• a solar cell array;
• an inverter provided between the solar cell array and a load;
• a switch provided between the inverter and the load for switching electrical connection between the inverter and the load;
• detection means for detecting whether an output of the solar cell array is a ground fault or not within an area between the solar cell array and the inverter;
• and
• protection means for outputting an inverter stop signal for stopping an operation of the inverter and then outputting an open signal for opening the switch based on a detection result of said detection means,
• wherein said protection means outputs the inverter stop signal when the ground fault is detected for a period longer than a first predetermined time T1, and outputs the open signal when the ground fault is detected for a period longer than a second predetermined time T2 (>T1).

A computer program product comprising a computer readable medium having computer program code, for protecting a solar power generation apparatus, said product comprising:

• detection process procedure code for detecting whether an output of a solar cell array is a ground fault or not within an area between the solar cell array and an inverter which is provided between the solar cell array and a load;
• first output process procedure code for outputting an inverter stop signal for stopping an operation of the inverter based on a detection result of said detection process;
• and
• second output process procedure code for, after output of the inverter stop signal, outputting an open signal for opening a switch provided between the inverter and the load based on the detection result,
• wherein the inverter stop signal is outputted when the ground fault is detected for a period longer than a first predetermined time T1, and the open signal is outputted when the ground fault is detected for a period longer than a second predetermined time T2 (>T1).