用于直流送端区域电网频率安全评估的Ip-SFR模型及其应用研究OA

With the rapid expansion of renewable energy bases in regions such as Northwest China and large-scale power transmission via ultra-high-voltage DC systems,HVDC sending-end grids are increasingly characterized by weak support and strong power export.Faults such as commutation failure and DC blocking can lead to short-term large power surplus,causing rapid frequency rise with spatiotemporal non-uniformity.Conventional center-of-inertia system frequency response models are insufficient for accurately evaluating peak frequency deviations.To address this issue,this paper proposes a two-area impulse-system frequency response(Ip-SFR)model to partition the grid into near-fault and remote areas.Considering tie-line synchronous power coupling and emergency control delays,an analytical frequency-response model is derived and a closed-form expression for the peak frequency deviation is obtained.Furthermore,frequency-security constraints suitable for day-ahead unit commitment is formulated.Case studies show that the proposed method aligns well with time-domain simulations.For typical DC faults at the sending end in Northwest regions,the maximum frequency deviation is reduced from 0.53 Hz/0.49 Hz to 0.44 Hz/0.41 Hz.The proposed approach can provide effective support for online assessment and dispatch optimization.