通过行驶里程、充放电时间及充放电方式等分析进行电动汽车的行为特性数学建模.采用基于拉丁超立方采样(Latin hypercube sampling,LHS)的蒙特卡洛模拟(Monte Carlo simulation,MCS)得到电动汽车充电功率的日负荷分布曲线,将其期望值和...通过行驶里程、充放电时间及充放电方式等分析进行电动汽车的行为特性数学建模.采用基于拉丁超立方采样(Latin hypercube sampling,LHS)的蒙特卡洛模拟(Monte Carlo simulation,MCS)得到电动汽车充电功率的日负荷分布曲线,将其期望值和方差与简单蒙特卡洛计算结果相比较,表明该方法比传统MCS具有良好的收敛速度和收敛精度.通过广州市电网负荷曲线算例,评估电动汽车充放电过程对电网负荷特性的影响,并揭示私家车双向有序充电与公交车集中充电相结合,可以在平抑负荷波动增大日负荷率的同时,有效降低日峰谷差率,从而既能保证用电单位经济合理用电,又有助于整个电网的安全经济运行.展开更多
One of the key challenges in the total maximum daily load(TMDL)development process is how to define the critical condition for a receiving waterbody.The main concern in using a continuous simulation approach is the ab...One of the key challenges in the total maximum daily load(TMDL)development process is how to define the critical condition for a receiving waterbody.The main concern in using a continuous simulation approach is the absence of any guarantee that the most critical condition will be captured during the selected representative hydrologic period,given the scarcity of long-term continuous data.The objectives of this paper are to clearly address the critical condition in the TMDL development process and to compare continuous and event-based approaches in defining critical condition during TMDL development for a waterbody impacted by both point and nonpoint source pollution.A practical,event-based critical flow-storm(CFS)approach was developed to explicitly addresses the critical condition as a combination of a low stream flow and a storm event of a selected magnitude,both having certain frequencies of occurrence.This paper illustrated the CFS concept and provided its theoretical basis using a derived analytical conceptual model.The CFS approach clearly defined a critical condition,obtained reasonable results and could be considered as an alternative method in TMDL development.展开更多
ELD （economic load dispatch） problem is one of the essential issues in power system operation. The objective of solving ELD problem is to allocate the generation output of the committed generating units. The main co...ELD （economic load dispatch） problem is one of the essential issues in power system operation. The objective of solving ELD problem is to allocate the generation output of the committed generating units. The main contribution of this work is to solve the ELD problem concerned with daily load pattern. The proposed solution technique, developed based PSO （particle swarm optimization） algorithm, is applied to search for the optimal schedule of all generations units that can supply the required load demand at minimum fuel cost while satisfying all unit and system operational constraints. The performance of the developed methodology is demonstrated by case studies in test system of six-generation units. The results obtained from the PSO are compared to those achieved from other approaches, such as QP （quadratic programming）, and GA （genetic algorithm）.展开更多
文摘通过行驶里程、充放电时间及充放电方式等分析进行电动汽车的行为特性数学建模.采用基于拉丁超立方采样(Latin hypercube sampling,LHS)的蒙特卡洛模拟(Monte Carlo simulation,MCS)得到电动汽车充电功率的日负荷分布曲线,将其期望值和方差与简单蒙特卡洛计算结果相比较,表明该方法比传统MCS具有良好的收敛速度和收敛精度.通过广州市电网负荷曲线算例,评估电动汽车充放电过程对电网负荷特性的影响,并揭示私家车双向有序充电与公交车集中充电相结合,可以在平抑负荷波动增大日负荷率的同时,有效降低日峰谷差率,从而既能保证用电单位经济合理用电,又有助于整个电网的安全经济运行.
基金This work was supported in part by the Virginia Department of Environmental Quality and the Virginia Environmental Endowment,Richmond,Virginia,USA.
文摘One of the key challenges in the total maximum daily load(TMDL)development process is how to define the critical condition for a receiving waterbody.The main concern in using a continuous simulation approach is the absence of any guarantee that the most critical condition will be captured during the selected representative hydrologic period,given the scarcity of long-term continuous data.The objectives of this paper are to clearly address the critical condition in the TMDL development process and to compare continuous and event-based approaches in defining critical condition during TMDL development for a waterbody impacted by both point and nonpoint source pollution.A practical,event-based critical flow-storm(CFS)approach was developed to explicitly addresses the critical condition as a combination of a low stream flow and a storm event of a selected magnitude,both having certain frequencies of occurrence.This paper illustrated the CFS concept and provided its theoretical basis using a derived analytical conceptual model.The CFS approach clearly defined a critical condition,obtained reasonable results and could be considered as an alternative method in TMDL development.
文摘ELD （economic load dispatch） problem is one of the essential issues in power system operation. The objective of solving ELD problem is to allocate the generation output of the committed generating units. The main contribution of this work is to solve the ELD problem concerned with daily load pattern. The proposed solution technique, developed based PSO （particle swarm optimization） algorithm, is applied to search for the optimal schedule of all generations units that can supply the required load demand at minimum fuel cost while satisfying all unit and system operational constraints. The performance of the developed methodology is demonstrated by case studies in test system of six-generation units. The results obtained from the PSO are compared to those achieved from other approaches, such as QP （quadratic programming）, and GA （genetic algorithm）.
