Method for Calculating the Equivalent Inertia of Power Systems Considering the Frequency Heterogeneity

To improve the safe and stable operation of the system and to provide risk warning and operation guidance, it is necessary to monitor the equivalent rotational inertia of the system. As the uneven distribution of rotational inertia in the system is becoming more and more obvious, the calculation method of rotational inertia by simple summing is extremely erroneous. This paper proposes a calculating method of power system rotational inertia that takes frequency heterogeneity into account. The definition and calculation method of perturbation power distribution factors is introduced in this paper, and its validity has been verified by simulation. Based on the perturbation power distribution factors, the equivalent rotational inertia of the system can be calculated more precisely for each power perturbation node, which can provide more accurate estimation of the frequency.