A Fast - Algorithmic Probabilistic Evaluation on Regional Rate of Change
of Frequency (RoCoF) for Operational Planning of High Renewable
Penetrated Power Systems
Abstract
The high rate of change of frequency (RoCoF) issue incurred by the
integration of renewable energy sources (RESs) into a modern power
system significantly threatens the grid security, and thus needs to be
carefully examined in the operational planning. However, severe
fluctuation of regional frequency responses concerned by system
operators could be concealed by the conventional assessment based on
aggregated system frequency response. Moreover, the occurrence
probability of a high RoCoF issue is actually a very vital factor during
the system planner’s decision making. Therefore, this paper proposes a
fast-algorithmic evaluation method to determine the probabilistic
distribution of regional RoCoF for the operational planning of a RES
penetrated power system. Firstly, an analytical sensitivity (AS) that
quantifies the relationship between the regional RoCoF and the
stochastic output of the RES is derived based on the generator and
network information. Then a linear sensitivity-based analytical method
(LSM) is established to calculate regional RoCoF and the corresponding
probabilistic distribution, which takes much less computational time
when comparing with the scenario-based simulation (SBS) and involves
much less complicated calculation procedure when comparing with the
cumulant-based method (CBM). The effectiveness and efficiency of the
proposed method are verified in a modified 16-machine 5-area IEEE
benchmark system by numerical SBS and analytical CBM.