In view of the network characteristics of the electric heating integrated energy system, the integrated energy system model considering the network characteristics is constructed, and the real marginal energy cost of the system is calculated. The method to solve the node marginal energy price of the integrated energy system considering the dynamic characteristics of the network is studied. First, a comprehensive energy system model considering network characteristics is constructed based on energy balance constraints. Then, based on the grid DC power flow model, the power transmission distribution factor is used to share the network loss, and the node marginal price is decomposed, including cost component, loss component and congestion component. The solution to the node marginal price is obtained, and the solution to the node gas price and node heat price is obtained by analogy. Finally, the node energy price is solved through numerical simulation, and the analysis shows that when the grid is blocked in a certain area, the marginal price here increases, and the node marginal signal can be used to urge users in the blocked area to change their energy consumption behavior and alleviate congestion.
Due to the uncertainty factors in the output of new energy such as wind power and photovoltaics,it is necessary to recalculate the probability power flow and analyze the static safety stability of new power systems with access to new energy.The Monte-Carlo method currently used has the problem of long computation time,making it difficult to apply in practical engineering.Based on the probability distribution characteristics of light intensity and wind speed,the output probability density function models for photovoltaic arrays and wind turbines respectively is constructed,and the semi-invariant method based on Gram-Charlie series expansion for probabilistic power flow calculation is used to realize power flow calculation and static stability analysis for new power systems with wind power and photovoltaic.In this paper,the IEEE(Institute of Electrical and Electronics Engineers)30 standard testing model is taken as an example to verify the proposed algorithm.The results show that the proposed algorithm maintains the high accuracy advantage of Monte-Carlo method while having a high computational speed.Furthermore,the influence of wind power and photovoltaic permeability on power flow and static safety stability of power system is studied.The results show that as the permeability increases,the range of flow distribution values expands and some branches may have negative values,leading to power reverse transmission issues and the increase of operational risk of the system.Then,the effects of line capacity expansion on reducing the risks of active power and node voltage exceeding limits,as well as improving static safety and stability are explored.
对于电力系统暂态电压安全评估与安全裕度估计的问题,传统的分析方法难以应对新型电力系统的复杂性与多样性,基于数据驱动的方法为暂态电压安全在线评估提供了新思路,但也存在着物理意义模糊、训练复杂度高、可拓展性差等问题.针对上述问题,提出了一种面向多故障场景的基于主动学习的暂态电压安全边界快速近似与安全裕度高效估计方法.首先,基于动态安全域的概念,针对训练复杂度高的问题,提出了基于主动学习的暂态电压安全评估模型与安全裕度估计的数据驱动方法,在保持较高准确率的同时极大地降低了标记样本集的规模,同时得到了解析的安全边界函数;然后,针对不同的故障信息,提出了基于shapelet变换的层次化事故聚类方法,将相似的故障聚集在一起,为每一类故障场景构建安全评估模型,使得暂态电压安全评估模型在一定程度上摆脱了故障依赖,提升了安全裕度在线估计的效率与精度;最后,通过IEEE39节点系统验证了所提方法的正确性,实现了多故障场景下暂态电压安全性的快速辨识与安全裕度的快速估计,有效降低了离线仿真的时间,提升了面向多故障场景的安全评估模型的部署效率.
在电网故障、功率波动等扰动工况下,并网变流器大幅偏离其设计工作点,威胁设备自身和电力系统安全.针对以上稳定运行问题,综述了电网同步、功率传输和开关调制环节的非线性行为机理,给出了常用的研究方法和结论.在此基础上,提出了并网变流器层次化安全边界,梳理了当前安全边界研究结果和应用方法,分析了各层边界的嵌套影响关系.最后对未来并网变流器的设计运行技术进行了展望.
建设海绵城市源头设施作为城市降雨径流控制的有效举措,受到世界各国的广泛关注.基于生命周期视角量化分析海绵城市源头设施建设和运行过程中的环境、经济影响与效益,可为海绵城市建设提供科学、全面的依据.采用内容分析法,综述分析了当前世界各国关于源头设施生命周期环境与经济效益的研究.研究结果表明,源头设施建设阶段会产生较高的环境影响及经济成本,但运行阶段会产生较大的环境与经济效益.当前研究存在的不足之处主要包括环境影响类别和设施种类单一、研究范围比较小及对环境与经济综合影响研究较少.最后,提出了海绵城市源头设施今后的研究方向,研究结果可为未来海绵城市量化研究提供一定的参考.
