考虑网络约束的能量枢纽灵活性价值评估

Value Evaluation of Energy Hub Flexibility Considering Network Constraints

分布式能源快速增长使配电系统灵活性需求剧增。能量枢纽因其在多能源调度运行和能量管理方面的巨大潜力而得到广泛关注。该文从配电网运行角度建立能量枢纽灵活性价值评估指标为:可再生能源削减量、失负荷量和线路拥塞程度,并基于此分析能量枢纽灵活性为区域配电系统带来的价值。首先,考虑冷热电联供为核心的能量枢纽,基于耦合矩阵建立能量枢纽灵活性耦合关系模型。接着,考虑可再生能源出力的不确定性,计及电-气网潮流约束建立多能源系统运行优化模型。优化模型引入3个评估指标作为松弛变量,既能反映系统的灵活性不足,又能在数学上保证优化问题有解。最后,提出基于惩罚-凸-凹流程的求解算法处理耦合网络约束中的非凸项。算例表明,考虑源侧电-气耦合和荷侧电-热-冷、气-热-冷互补的能量枢纽灵活性在促进可再生能源消纳、避免失负荷和缓解线路拥塞方面起到积极作用。

The rapid growth of distributed energy resources has increased flexibility demand in the distribution system.Energy hubs(EHs) have received extensive attention due to their great flexibility potential in multi-energy dispatching operation and energy management. This paper established three value evaluation indicators of EH flexibility including the renewable energy source(RES) curtailment, load shedding, and line congestion, from the perspective of distribution network operation. Based on evaluation indicators, the value brought by the EH flexibility to the regional power distribution system was analyzed. First, the EH with the combined cooling heating and power was considered, and its flexible coupling relationship was established based on the coupling matrix. Then, the regional energy system operation optimization model considering the uncertainty of RES and the coupled power flow constraints was established. The three evaluation indicators were embedded into the objective function as penalty items, so as to schedule the EH flexibility as much as possible to avoid the occurrence of penalty. Finally, a penalty convex-concave procedure(PCCP) algorithm was designed to deal with the non-convex terms in the power flow constraints. The case study shows that the EH flexibility that considers gas-electric coupling on the source side and electric-heat-cold, gas-heatcold complementarity on the load side plays a positive role in promoting the RES consumption, avoiding load loss and line congestion.