Control of a renewable energy power plant to resume normal operation following a fault

A computer program downloadable from a communication network or stored on a machine readable medium, comprising program code instructions for implementing an operation of a renewable energy power plant comprising a plurality of renewable energy generators, the operation comprising:

• operating a first reactive power controller to output a present reactive power reference level, the first reactive power controller configured to operate in a fault ride-through mode during a grid fault;
• operating a second reactive power controller to output a target reactive power reference level, the second reactive power controller configured to operate following the grid fault in a normal operational mode as if the grid fault had not occurred;
• calculating a rate of change of reactive power reference level for transitioning between the present reactive power reference level and the target reactive power reference level, the target reactive power reference level being suitable for normal operation of the renewable energy power plant;
• and
• following a fault on a power network to which the renewable energy power plant is connected, dispatching a control signal for controlling the renewable energy power plant to generate or consume reactive power at the calculated rate of change to transition a reactive power level of the renewable energy power plant to the target reactive power reference level.