We report a novel battery-less wireless current sensor node without an analog to digital converter (ADC). If a capacitor is charged using a current transformer (CT) and a rectifying circuit, the charging time depends ...We report a novel battery-less wireless current sensor node without an analog to digital converter (ADC). If a capacitor is charged using a current transformer (CT) and a rectifying circuit, the charging time depends on the current flowing through a power line. In the case that the node transmits data every time when voltage of the capacitor exceeds a threshold voltage, we can indirectly measure the current by measuring the transmission intervals. In this method, the circuit of the node can be simplified and power consumption for the wireless transmission can be decreased because the measured current data does not need to be included in the transmitted packet. However, the measurable range is about single digit because the transmission interval decreases suddenly as the current increases. In this work, we have ex- panded the range using one CT, one wireless transmission module, and two charging circuits that include different load resistors connected in series. The results indicated that the measurable range was from 0.5 A to 50 A.展开更多
The continuation power flow method combined with the Jacobi-Davidson method is presented to trace the critical eigenvalues for power system small signal stability analysis. The continuation power flow based on a predi...The continuation power flow method combined with the Jacobi-Davidson method is presented to trace the critical eigenvalues for power system small signal stability analysis. The continuation power flow based on a predictor- corrector technique is applied to evaluate a continuum of steady state power flow solutions as system parameters change;meanwhile, the critical eigenvalues are found by the Jacobi-Davidson method, and thereby the trajectories of the critical eigenvalues, Hopf bifurcation and saddle node bifurcation points can also be found by the proposed method. The numerical simulations are studied in the IEEE 30-bus test system.展开更多
In Wireless Sensor Network (WSNs), sensor nodes collect data and send them to a Base Station (BS) for further processing. One of the most issues in WSNs that researchers have proposed a hundred of technique to solve i...In Wireless Sensor Network (WSNs), sensor nodes collect data and send them to a Base Station (BS) for further processing. One of the most issues in WSNs that researchers have proposed a hundred of technique to solve its impact is the energy constraint since sensor nodes have small battery, small memory and less data processing with low computational capabilities. However, many researches efforts have focused on how to prolong the battery lifetime of sensor nodes by proposing different routing, MAC, localization, data aggregation, topology construction techniques. In this paper, we will focus on routing techniques which aim to prolonging the network lifetime. Hence, we propose an Energy-Efficient Routing technique in WSNs based on Stationary and Mobile nodes (EERSM). Sensing filed is divided into intersected circles which contain Mobile Nodes (MN). The proposed data aggregation technique via the circular topology will eliminate the redundant data to be sent to the Base Station (BS). MN in each circle will rout packets for their source nodes, and move to the intersected area where another MN is waiting (sleep mode) to receive the transmitted packet, and then the packet will be delivered to the next intersected area until the packet is arrived to the BS. Our proposed EERSM technique is simulated using MATLAB and compared with conventional multi-hop techniques under different network models and scenarios. In the simulation, we will show how the proposed EERSM technique overcomes many routing protocols in terms of the number of hops counted when sending packets from a source node to the destination (i.e. BS), the average residual energy, number of sent packets to the BS, and the number of a live sensor nodes verse the simulation rounds.展开更多
突发性自然灾害经常对大型工程的建筑与生产设施造成重大损失,而受损设施的维修和重建过程常出现物资供给不足、物资供给效率低以及物资分配公平性等问题。本文以某大型光伏电站为依托,从应急物资节点选址影响因素入手,建立受突发性灾...突发性自然灾害经常对大型工程的建筑与生产设施造成重大损失,而受损设施的维修和重建过程常出现物资供给不足、物资供给效率低以及物资分配公平性等问题。本文以某大型光伏电站为依托,从应急物资节点选址影响因素入手,建立受突发性灾害作用后的应急物资节点选址评价指标系统,采用AHP-CRITIC(analyt⁃ic hierarchy process-criteria importance through intercriteria correlation)组合赋权法实现应急物资存放点选址评价结果的计算。同时,基于研究区内部路网开展大型光伏场地路口至多物资存储节点的最优路径研究,并采用GIS(geographic information system)技术求解出最短运输路径。结果表明:该大型光伏场地应急物资节点选址评价结果等级为“好”与“较好”的区域主要分布在研究区北部,占总面积的33.38%;基于最短运输路径原则通过综合对比线路总长与重复路线占比,由入口3出发至各应急物资节点的路径为最优路线。研究成果可为类似大型工程的安全运营和应急管理提供技术支持和参考。展开更多
文摘We report a novel battery-less wireless current sensor node without an analog to digital converter (ADC). If a capacitor is charged using a current transformer (CT) and a rectifying circuit, the charging time depends on the current flowing through a power line. In the case that the node transmits data every time when voltage of the capacitor exceeds a threshold voltage, we can indirectly measure the current by measuring the transmission intervals. In this method, the circuit of the node can be simplified and power consumption for the wireless transmission can be decreased because the measured current data does not need to be included in the transmitted packet. However, the measurable range is about single digit because the transmission interval decreases suddenly as the current increases. In this work, we have ex- panded the range using one CT, one wireless transmission module, and two charging circuits that include different load resistors connected in series. The results indicated that the measurable range was from 0.5 A to 50 A.
文摘The continuation power flow method combined with the Jacobi-Davidson method is presented to trace the critical eigenvalues for power system small signal stability analysis. The continuation power flow based on a predictor- corrector technique is applied to evaluate a continuum of steady state power flow solutions as system parameters change;meanwhile, the critical eigenvalues are found by the Jacobi-Davidson method, and thereby the trajectories of the critical eigenvalues, Hopf bifurcation and saddle node bifurcation points can also be found by the proposed method. The numerical simulations are studied in the IEEE 30-bus test system.
文摘In Wireless Sensor Network (WSNs), sensor nodes collect data and send them to a Base Station (BS) for further processing. One of the most issues in WSNs that researchers have proposed a hundred of technique to solve its impact is the energy constraint since sensor nodes have small battery, small memory and less data processing with low computational capabilities. However, many researches efforts have focused on how to prolong the battery lifetime of sensor nodes by proposing different routing, MAC, localization, data aggregation, topology construction techniques. In this paper, we will focus on routing techniques which aim to prolonging the network lifetime. Hence, we propose an Energy-Efficient Routing technique in WSNs based on Stationary and Mobile nodes (EERSM). Sensing filed is divided into intersected circles which contain Mobile Nodes (MN). The proposed data aggregation technique via the circular topology will eliminate the redundant data to be sent to the Base Station (BS). MN in each circle will rout packets for their source nodes, and move to the intersected area where another MN is waiting (sleep mode) to receive the transmitted packet, and then the packet will be delivered to the next intersected area until the packet is arrived to the BS. Our proposed EERSM technique is simulated using MATLAB and compared with conventional multi-hop techniques under different network models and scenarios. In the simulation, we will show how the proposed EERSM technique overcomes many routing protocols in terms of the number of hops counted when sending packets from a source node to the destination (i.e. BS), the average residual energy, number of sent packets to the BS, and the number of a live sensor nodes verse the simulation rounds.
文摘突发性自然灾害经常对大型工程的建筑与生产设施造成重大损失,而受损设施的维修和重建过程常出现物资供给不足、物资供给效率低以及物资分配公平性等问题。本文以某大型光伏电站为依托,从应急物资节点选址影响因素入手,建立受突发性灾害作用后的应急物资节点选址评价指标系统,采用AHP-CRITIC(analyt⁃ic hierarchy process-criteria importance through intercriteria correlation)组合赋权法实现应急物资存放点选址评价结果的计算。同时,基于研究区内部路网开展大型光伏场地路口至多物资存储节点的最优路径研究,并采用GIS(geographic information system)技术求解出最短运输路径。结果表明:该大型光伏场地应急物资节点选址评价结果等级为“好”与“较好”的区域主要分布在研究区北部,占总面积的33.38%;基于最短运输路径原则通过综合对比线路总长与重复路线占比,由入口3出发至各应急物资节点的路径为最优路线。研究成果可为类似大型工程的安全运营和应急管理提供技术支持和参考。
