The distribution networks sometimes suffer from excessive losses and voltage violations in densely populated areas. The aim of the present study is to improve the performance of a distribution network by successively ...The distribution networks sometimes suffer from excessive losses and voltage violations in densely populated areas. The aim of the present study is to improve the performance of a distribution network by successively applying mono-capacitor positioning, multiple positioning and reconfiguration processes using GA-based algorithms implemented in a Matlab environment. From the diagnostic study of this network, it was observed that a minimum voltage of 0.90 pu induces a voltage deviation of 5.26%, followed by active and reactive losses of 425.08 kW and 435.09 kVAR, respectively. Single placement with the NSGAII resulted in the placement of a 3000 kVAR capacitor at node 128, which proved to be the invariably neuralgic point. Multiple placements resulted in a 21.55% reduction in losses and a 0.74% regression in voltage profile performance. After topology optimization, the loss profile improved by 65.08% and the voltage profile improved by 1.05%. Genetic algorithms are efficient and effective tools for improving the performance of distribution networks, whose degradation is often dynamic due to the natural variability of loads.展开更多
为解决交通网络与供水管网之间耦合关系所引发各类突发事件级联失效作用及其建模量化问题,以上海市中心城区为案例,利用出租车GPS数据及道路、供水管网GIS(Geographic Information System)数据,通过空间匹配和时间属性融合建立动态耦合...为解决交通网络与供水管网之间耦合关系所引发各类突发事件级联失效作用及其建模量化问题,以上海市中心城区为案例,利用出租车GPS数据及道路、供水管网GIS(Geographic Information System)数据,通过空间匹配和时间属性融合建立动态耦合网络,基于渗流理论提出网络影响力指数用于量化级联失效影响。结果表明,交通网络和供水管网之间存在显著的时空耦合效应,尤其在高峰时段供水管网的失效对交通网络的连通性和运行效率产生了直接影响。同时,通过构建解耦策略,提出管网规划和维护优化方案,可减少2个网络之间跨网络级联失效影响,可为提升城市关键基础设施韧性安全与运行可靠性提供参考。展开更多
文摘The distribution networks sometimes suffer from excessive losses and voltage violations in densely populated areas. The aim of the present study is to improve the performance of a distribution network by successively applying mono-capacitor positioning, multiple positioning and reconfiguration processes using GA-based algorithms implemented in a Matlab environment. From the diagnostic study of this network, it was observed that a minimum voltage of 0.90 pu induces a voltage deviation of 5.26%, followed by active and reactive losses of 425.08 kW and 435.09 kVAR, respectively. Single placement with the NSGAII resulted in the placement of a 3000 kVAR capacitor at node 128, which proved to be the invariably neuralgic point. Multiple placements resulted in a 21.55% reduction in losses and a 0.74% regression in voltage profile performance. After topology optimization, the loss profile improved by 65.08% and the voltage profile improved by 1.05%. Genetic algorithms are efficient and effective tools for improving the performance of distribution networks, whose degradation is often dynamic due to the natural variability of loads.
文摘为解决交通网络与供水管网之间耦合关系所引发各类突发事件级联失效作用及其建模量化问题,以上海市中心城区为案例,利用出租车GPS数据及道路、供水管网GIS(Geographic Information System)数据,通过空间匹配和时间属性融合建立动态耦合网络,基于渗流理论提出网络影响力指数用于量化级联失效影响。结果表明,交通网络和供水管网之间存在显著的时空耦合效应,尤其在高峰时段供水管网的失效对交通网络的连通性和运行效率产生了直接影响。同时,通过构建解耦策略,提出管网规划和维护优化方案,可减少2个网络之间跨网络级联失效影响,可为提升城市关键基础设施韧性安全与运行可靠性提供参考。
文摘针对不同磁密幅值、频率、谐波组合等复杂激励工况下磁致伸缩建模面临的精准性问题,该文利用空间注意力机制(spatial attention mechanism,SAM)对传统的卷积神经网络(convolutional neural network,CNN)进行改进,将SAM嵌套入CNN网络中,建立SAMCNN改进型网络。再结合双向长短期记忆(bidirectional long short-term memory,BiLSTM)网络,提出电工钢片SAMCNN-BiLSTM磁致伸缩模型。首先,利用灰狼优化算法(grey wolf optimization,GWO)寻优神经网络结构的参数,实现复杂工况下磁致伸缩效应的准确表征;然后,建立中低频范围单频与叠加谐波激励等复杂工况下的磁致伸缩应变数据库,开展数据预处理与特征分析;最后,对SAMCNN-BiLSTM模型开展对比验证。对比叠加3次谐波激励下的磁致伸缩应变频谱主要分量,SAMCNN-BiLSTM模型计算值最大相对误差为3.70%,其比Jiles-Atherton-Sablik(J-A-S)、二次畴转等模型能更精确地表征电工钢片的磁致伸缩效应。
