计及大规模新能源接入的电–气耦合综合能源系统稳定性评估

Stability Assessment of Electro-gas Coupled Integrated Energy System Considering Large-scale New Energy Access

在新能源渗透率不断提高及能源耦合越来越紧密的背景下,针对典型电–气耦合综合能源系统(electro-gas coupled integrated energy system,EGCIES),提出一种基于大规模新能源并网的电–气耦合综合能源系统稳定性评估方法。首先给出电–气耦合综合能源系统潮流的顺序求解方法,在计及电力系统(electrical power system,EPS)与天然气系统(natural gas system,NGS)能量耦合关系的情况下,考虑新能源机组出力不确定性及电负荷、气负荷的随机波动,求解EGCIES潮流;然后提出了一种最小切负荷策略,在EPS中将三级切负荷策略与改进二分法相结合,并将其应用于NGS系统中,以快速准确求解极端状况下,系统的最小切负荷量;又在电源点、气源点的故障情况下,计及电–气耦合特性,通过所提出的稳定性分析方法,从EPS稳定性、NGS稳定性及EPS与NGS耦合能力多角度定量分析电–气耦合综合能源系统的稳定性,并求解EPS与NGS能量互补的拐点。最后,利用比利时20节点天然气系统及IEEE39节点系统构成电–气耦合综合能源系统,验证了所提方法的有效性。

In the context of the continuous improvement of new energy penetration rate and the increasingly close energy coupling, a large-scale new energy grid connection based stability evaluation method is proposed for the Electro-Gas Coupled Integrated Energy System(EGGIES). Firstly, a sequential solution model for the power flow of an electric-gas coupled integrated energy system is given. The EGCIES trend is solved by considering the energy coupling between the electrical system(EPS) and the natural gas system(NGS), and by concerning the uncertainty output and the random fluctuation of electric load and gas load. Secondly, a minimum load shedding strategy is proposed. Through combining the three-stage load shedding strategy with the improved dichotomy in EPS and applying it to the NGS system, the minimum load shedding of the system under extreme conditions can be solved quickly and accurately. Thirdly, under the fault conditions of the power supply point and the gas source point, the quantitative analysis of the stability of the electro-pneumatic coupled integrated energy system is given and the complementary inflection point of the EPS and NGS energy is obtained by considering the electro-mechanical coupling characteristics and by using the method proposed in this paper. Finally, the effectiveness of the proposed method is verified with an electro-pneumatic coupled integrated energy system formed by using the Belgian 20-node natural gas system and the IEEE 39-node system.