基于广义短路比的光伏多馈入系统容量优化方法

广义短路比可用于描述电力电子多馈入系统小干扰稳定性,基于此指标研究了光伏发电(或场)多点馈入电网的总容量一定时,各点接入容量优化分配的问题,使光伏多馈入系统的小干扰稳定裕度最大。首先,建立了光伏多馈入系统的小干扰稳定分析模型;其次,利用广义短路比关于各馈入点光伏接入容量的灵敏度,提出了光伏多馈入系统的并网点容量优化方法;最后,以光伏三馈入系统为例,验证所提容量优化方法的可行性和有效性。仿真结果表明,合理分配多点接入时光伏的并网容量,能够有效提高系统的广义短路比和小干扰稳定裕度。

Capacity Optimization Method for Multi-infeed Photovoltaic System Based on Generalized Short Circuit Ratio

Generalized short circuit ratio (gSCR) is able to characterize the small signal stability of multi-infeed system with power electronic devices. Based on the gSCR index, the allocation optimization problem of grid-connected capacity of each feeding point is investigated when the total grid-connected capacity of photovoltaic (PV) devices (or fields) is fixed to make the small signal stability margin of multi-infeed PV system maximized.Firstly, the small signal stability analysis model for multi-infeed PV system is established.Secondly, based on the sensitivity of gSCR to grid-connected PV capacity at each feeding point, a capacity optimization method for multi-infeed PV system is proposed. Finally, with three-infeed PV system as an calculation example, the feasibility and effectiveness of the proposed capacity optimization method are verified.The simulation results show that the reasonable distribution of grid-connected PV capacity accessed to multiple points can effectively enhance the gSCR of multi-infeed PV system and increase the small signal stability margin.