Hybrid power plant fast frequency response

1 . A method of controlling a hybrid power plant connected to a power network, the hybrid power plant comprising at least two types of renewable energy generator having an active power reserve for supplying additional active power to the power network, the method comprising, during a frequency event detected on the power network:

determining, based at least in part, on the frequency event, an additional amount of active power for the hybrid power plant to provide to the power network to provide a frequency response;

calculating, based on a priority sequence configuration and the active power reserve of the at least two types of renewable energy generator, a contribution from each of the at least two types of renewable energy generator for supplying the additional amount of active power, wherein the priority sequence configuration comprises a sequence in which the at least two types of renewable energy generator should cumulatively provide a maximum-possible contribution to the additional amount; and

generating and dispatching active power requests to the generators for supplying the additional amount according to the calculated contributions,

wherein at least one type of the at least two types of renewable energy generator is configured to contribute active power from a reserve and using an over-boost mechanism, and wherein the sequence includes an entry for the reserve and an entry for the over-boost, the entry for the reserve being earlier in the sequence than the entry for the over-boost, and wherein the over-boost mechanism is a capability of the at least one type to supply active power above a rated value.

2 . The method of claim 1 , wherein calculating the contribution comprises comparing, in an order of types of generator of the priority sequence, a remainder of the additional amount with an available capacity of reserve of the generators, and wherein, if the remainder exceeds the available capacity of the generators, then the contribution is set to equal to the available capacity, and wherein, if the available capacity exceeds the remainder, then the contribution is set to equal to the remainder.

3 . The method of claim 1 , comprising, during a period of post-over-boost recovery during which the active power contribution of one type of generator drops below a nominal level, compensating for at least part of the drop using the reserve of a different type of generator.

4 . The method of claim 3 , wherein the reserve of the type of generators providing compensation is reserved for compensation only.

5 . The method of claim 3 , wherein the reserve of the type of generators is divided into reserve for use in providing contribution to the additional amount and reserve for compensation.

6 . The method of claim 3 , wherein the type of generators providing compensation comprises battery energy storage.

7 . The method of claim 1 , wherein calculating the contribution comprises comparing a demand ramp rate with a ramp rate limit for a type of generator in the sequence, and, if the demand ramp rate exceeds the ramp rate limit, calculating a contribution from the next type of generator in the sequence to meet the demand ramp rate.

8 . The method of claim 1 , wherein the hybrid power plant comprises at least two types of generator selected from a list comprising: wind turbine generators; a battery energy storage system; and/or photovoltaic generators.

9 . The method of claim 8 , wherein the hybrid power plant comprises wind turbine generators, a battery energy storage system, and photovoltaic generators, and wherein the wind turbine generators and photovoltaic generators are before the battery energy storage system in the priority sequence.

10 . The method of claim 8 , wherein a slave wind power plant is provided as a separate type of renewable energy generator to the wind turbine generators of the hybrid power plant.

11 . A method of controlling a hybrid power plant connected to a power network, the hybrid power plant comprising at least two types of renewable energy generator having an active power reserve for supplying additional active power to the power network, the method comprising, during a frequency event detected on the power network:

determining an additional amount of active power to be provided by the hybrid power plant to the power network to provide a frequency response;

calculating, based on a preset configuration and the active power reserve of the generators, a contribution from each of the at least two types of generator for supplying the additional amount of active power, wherein the preset configuration comprises a percentage split of the additional amount between the at least two types of generators;

generating and dispatching active power requests to the generators for supplying the additional amount according to the calculated contributions; and

comprising comparing, for each type of generator, the calculated contribution with an available capacity of reserve of the generators, and, if the calculated contribution exceeds the available capacity, adjusting the percentage split to account for the exceedance; wherein at least one type of generator is configured to contribute active power from a reserve and using an over-boost mechanism, and wherein the percentage split includes a percentage for the reserve and a percentage for the over-boost.