WANG Yizhen, PEI Aifei, JI Yirun, et al. Linear Optimal Power Flow of DC Grids Considering VSC Control Characteristics[J]. 2026, 46(13): 5349-5357.DOI: 10.13334/j.0258-8013.pcsee.250608.
直流电网为可再生能源集成提供了一种可行且前景广阔的解决方案。面对可再生能源的波动性、间歇性和负荷的随机性带来的功率波动问题,直流系统需要根据最优潮流(optimal power flow,OPF)结果更新电压源型换流器(voltage source converter,VSC)的运行点以保持直流系统稳定经济运行。然而,传统的OPF计算效率低,无法用于直流系统的实时控制。因此,该文提出一种考虑VSC控制特性的直流电网线性最优潮流。首先,以电压偏差、网损、调度指令偏差最小为目标建立直流电网的OPF模型;其次,将潮流等式约束和优化目标进行部分线性化;随后,通过拉格朗日乘数法和VSC控制特性将直流电网OPF模型完全线性化至两个线性方程,获得VSC的最优运行点;最后,基于Cigre B4测试系统验证所提直流电网线性OPF的正确性和有效性。与传统OPF相比,在10节点直流电网中,所提线性OPF在误差3%以内能够将计算速度提高100倍以上,节省了99%以上的计算时间。
Abstract
DC Grids provide a feasible and promising solution for renewable energy integration. To address the power fluctuation issues caused by the volatility and intermittency of renewable energy and the randomness of loads
the DC system needs to update the operating points of voltage source converters (VSCs) based on optimal power flow (OPF) results to maintain stable and economical operation. However
the traditional OPF methods are computationally inefficient and unsuitable for real-time control of DC systems. Therefore
this paper proposes a linear OPF of DC grids considering VSC control characteristics. First
an OPF model for DC grids is formulated with the objectives of minimizing voltage deviation
power losses
and dispatch deviations. Second
the power flow equality constraints and optimization objectives are partially linearized. Subsequently
the DC grid OPF model is fully linearized using the Lagrange multipliers and the generalized VSC control characteristics
obtaining the optimal operating points for the VSCs. Finally
the effectiveness of the proposed linear OPF for DC grids is validated using the Cigre B4 DC test system. Compared with conventional OPF
in a 10-node DC grid
the proposed linear OPF improves computation speed by over 100 times and saves more than 99% of computation time while keeping the error within 3%.