Weak Grid State Identification Based On Current Spectrum

With the increase of the penetration rate of new energy in the power grid and the need for long-distance transmission, the strength of the current traditional power grid is not as good as before. The weakening of the power grid will bring a series of problems, among which the resonance problem is the most significant. Starting with the resonance frequency, this paper analyzes the interaction point between the inverter output impedance and the amplitude-frequency characteristics of the power grid impedance, and obtains the distribution characteristics of the frequency when the weak power grid occurs, and realizes the identification function of the weak power grid according to this feature. Finally, the effectiveness and feasibility of the proposed identification scheme are verified by simulation.