  Wind generation is expected to reach substantially higher levels of
penetration in the near future. With the converter interface, the rotor inertia
of doubly-fed induction generator (DFIG) based wind turbine generator is
effectively decoupled from the system, causing a reduction in inertial
response. This can be compensated by enabling the DFIG to provide fast
frequency response. This paper proposes a quantitative control approach for
DFIG to deliver fast frequency response in the inertial response time scale. A
supplementary power surge function is added to the active power reference of
DFIG. The exact amount of power surge that is available from DFIG-based wind
turbine is quantified based on estimation of maximum extractable energy.
Moreover, the operational constraints such as rotor limits and converter
over-load limit are considered at the same time. Thus, the proposed approach
not only provides adequate inertial response but also ensures the rotor speed
is kept within a specified operating range. Rotor safety is guaranteed without
the need for an additional rotor speed protection scheme.
