Frequency Characteristics of Southwest Power Grid and Scheme of Over-Frequency Generator Tripping

Abstract

Based on the single machine model, the key factors affecting the frequency response of the system are studied, the expressions of the initial frequency change rate and the maximum frequency deviation after large disturbance are derived, and the mechanism of improving the frequency stability of conventional units and new energy frequency response, DC frequency modulation, load frequency response, emergency control and other factors is analyzed. According to the frequency response characteristics of Southwest Power Grid, the over-frequency generator tripping scheme is designed from the aspects of high frequency generator tripping object, starting threshold, generator tripping capacity, etc., and the coordination principle of high cycle generator tripping, generator overspeed protection and low frequency load shedding is proposed. The effectiveness of the proposed scheme is verified by practical examples.