Minimum inertia estimation of power-electronized power system
considering multi-resource frequency response characteristics
Abstract
With the large-scale grid connection of power electronic power sources,
the power system gradually exhibits the characteristics of ‘low
inertia’, and the indexes of frequency characteristics are getting
closer to the safety critical value, which seriously affects the
frequency safety of the system operation. To quantitatively analyze the
minimum inertia requirement of the power electronic power system under
the condition of multi-resource participation in frequency regulation
(FR) when it is disturbed by active power, based on the improved
frequency response model of the multi-machine system, this paper
proposes a minimum inertia estimation method of the power system
considering the frequency response characteristics. The theoretical
inertia of each FR unit is represented in the form of rotor kinetic
energy, and the calculated inertia of the power system is quantified
based on the Rate of Change of Frequency (RoCoF). The sliding window
technique is used to select the data set with the smallest variance and
obtain the final calculated inertia of the system. The proposed
estimation method takes the initial RoCoF, the maximum frequency
deviation, and the steady-state frequency deviation as the frequency
change constraint indicators, and adds the minimum inertia improvement
measures to reduce the demand for the minimum inertia. Finally, the
PSD-BPA software is used to verify the accuracy of the proposed model.
And based on the improved frequency response model of the multi-machine
system, MATLAB/Simulink is used to verify the proposed minimum inertia
estimation method.