Current injection in wind power plants

A renewable energy power plant comprising:

• a plurality of renewable energy generators;
• a power network connecting the plurality of renewable energy generators to a Point of Interconnection (PoI) to an external power grid;
• and
• a power plant controller configured to, during normal operating conditions before occurrence of a grid fault:
• monitor at least one parameter of the power network;
• modify a predetermined injection profile based on the at least one parameter to generate a current injection profile, wherein the current injection profile indicates output current as a function of measured voltage;
• communicate the current injection profile and a reference value to a controller of a renewable energy generator of the plurality of renewable energy generators;
• store the current injection profile;
• and
• operate the renewable energy generator according to the reference value provided by the power plant controller rather than the current injection profile;
• and
• wherein during the grid fault:
• at least one of a voltage across a terminal of the renewable energy generator or a voltage at the power network is measured;
• the controller of the renewable energy generator calculates an output current based on (i) the at least one of the voltage across the terminal of the renewable energy generator or the voltage of the power network and (ii) the stored current injection profile communicated by the power plant controller during normal operating conditions;
• and
• the controller of the renewable energy generator operates the renewable energy generator to produce the output current.

A computer program stored on a machine-readable medium and comprising program code instructions which, when executed, perform an operation for controlling a renewable energy generator that is connected to a Point of Interconnection of an external power grid by a connecting network, the operation comprising:

• during normal operating conditions before occurrence of a grid fault:
• monitoring at least one parameter of the connecting network;
• modifying, by a power plant controller of a power plant comprising the renewable energy generator, a predetermined injection profile based on the at least one parameter to generate a current injection profile, wherein the current injection profile indicates output current as a function of measured voltage;
• communicating the current injection profile and a reference value to a controller of the renewable energy generator;
• storing, by the controller of the renewable energy generator, the current injection profile;
• and
• operating the renewable energy generator according to the reference value provided by the power plant controller rather than the current injection profile;
• and
• during the grid fault:
• measuring at least one of a voltage across a terminal of the renewable energy generator or a voltage at the connecting network;
• calculating, by the controller of the renewable energy generator rather than the power plant controller, an output current based on (i) the at least one of the voltage across the terminal of the renewable energy generator or the voltage of the connecting network and (ii) the stored current injection profile communicated by the power plant controller during normal operating conditions;
• and
• operating, by the controller of the renewable energy generator rather than the power plant controller, the renewable energy generator to produce the output current.