[Objective] The aim was to study the characteristics of the spatial structural patterns and temporal variability of annual precipitation in Ningxia.[Method] Using rotated empirical orthogonal function,the precipitatio...[Objective] The aim was to study the characteristics of the spatial structural patterns and temporal variability of annual precipitation in Ningxia.[Method] Using rotated empirical orthogonal function,the precipitation concentration index,wavelet analysis and Mann-Kendall rank statistic method,the characteristics of precipitation on the spatial-temporal variability and trend were analyzed by the monthly precipitation series in Ningxia during 1951-2008.[Result] In Ningxia,the spatial structural patterns of annual precipitation appeared 'North-south type' and 'North-center-south type'.It increased from north to south,the changes of interannual precipitation decreased from north to south.Precipitation changed significantly in month and distributed differently in the Yellow River irrigation area.But it was conversely steady in central arid zone and mountainous area of southern Ningxia.The probability of single abundant precipitation year was higher than single short precipitation year and the continuous short precipitation year was higher than continuous abundant precipitation year.The main cycles were 3a,6a and 10a approximately.In the mid arid zone and the mountainous area of southern Ningxia,the probability of precipitation reduction was about 75% and the Yellow river irrigation area,71.4%,respectively.The reduction in the entire area was about 73.3%.The annual precipitation in the middle arid area and irrigation area was increasing.The variability would change slowly for the intra-annual distribution of precipitation.Especially,the reduction tendency rate in the middle arid area reached 100.0%.[Conclusion] The study provided references for the effective utilization of the local precipitation,and the coordinated development of the regional social economy and ecological environment.展开更多
针对主动配电系统(active distribution system,ADS)中间歇性电源和负荷的不确定性问题,基于多场景技术提出一种两步优化调度模型。首先分析了ADS中各单元的概率模型,其次采用拉丁超立方抽样及样本缩减技术得到各单元的样本,进而构建了...针对主动配电系统(active distribution system,ADS)中间歇性电源和负荷的不确定性问题,基于多场景技术提出一种两步优化调度模型。首先分析了ADS中各单元的概率模型,其次采用拉丁超立方抽样及样本缩减技术得到各单元的样本,进而构建了研究场景。在此基础上兼顾供电公司利益、污染物排放等目标,引入可中断负荷等相关约束,提出一种包含日前调度和实时调度的主动配电系统两步优化调度模型,并分别利用基于动态交换和密度距离的混沌粒子群算法和二进制粒子群算法求解日前调度和实时调度模型,算例结果表明所提模型和算法的有效性和正确性。展开更多
传统的电网可靠性评估采用固定不变的元件年均故障率模型,难以适应电力系统短期风险评估需求。电网故障与灾害性天气具有较强的时间相关性,气象灾害具有明显的季节性特征,因此电网风险也具有时间波动性。在描述电网元件故障参数时,需要...传统的电网可靠性评估采用固定不变的元件年均故障率模型,难以适应电力系统短期风险评估需求。电网故障与灾害性天气具有较强的时间相关性,气象灾害具有明显的季节性特征,因此电网风险也具有时间波动性。在描述电网元件故障参数时,需要从原来的一维横向连续时间下的年均值模型,拓展到考虑历史同期(纵向)时间和导致故障的因素,特别是外部气象环境因素,以便更准确地描述时间及环境相依的电网故障率。在传统年均值模型的基础上建立了不同时间尺度、不同气象灾害类型下的元件故障模型,并依据此模型进行电网可靠性评估。按照该方法对西南某省级电网近3年内500 k V输电线路的故障数据进行了分析,对该电网的可靠性进行了评估。计算结果表明,不同时间段电网的可靠性指标与年均值相比具有较大差异,验证了时空环境相依的可靠性评估的必要性。展开更多
作为能源技术与互联网信息技术相融合的产物,能源互联网的构建离不开大型数据服务中心互联的支撑。然而,当前互联网数据中心(Internet Data Center,IDC)巨大能耗所带来的成本和环境压力,突显出对IDC能耗管理的重要性。文中基于实时电价...作为能源技术与互联网信息技术相融合的产物,能源互联网的构建离不开大型数据服务中心互联的支撑。然而,当前互联网数据中心(Internet Data Center,IDC)巨大能耗所带来的成本和环境压力,突显出对IDC能耗管理的重要性。文中基于实时电价和多电力市场构成的能源互联网市场环境,在考虑IDC散热成本、碳排放成本以及服务延迟约束的基础上,以IDC负荷周期内总的能耗成本最小化为目标,建立了IDC数据负荷在多时空尺度下的优化调度模型,并采用反馈分支定界算法对模型求解。最后,通过算例仿真验证所提方案的正确性,仿真结果表明该技术可以显著降低IDC的能耗成本。展开更多
基金Supported by Ningxia Natural Science Fund (NZ10215)National Science and Technology Planning Project (2011BAD29B07)Ningxia Natural Science Fund (NZ10214)
文摘[Objective] The aim was to study the characteristics of the spatial structural patterns and temporal variability of annual precipitation in Ningxia.[Method] Using rotated empirical orthogonal function,the precipitation concentration index,wavelet analysis and Mann-Kendall rank statistic method,the characteristics of precipitation on the spatial-temporal variability and trend were analyzed by the monthly precipitation series in Ningxia during 1951-2008.[Result] In Ningxia,the spatial structural patterns of annual precipitation appeared 'North-south type' and 'North-center-south type'.It increased from north to south,the changes of interannual precipitation decreased from north to south.Precipitation changed significantly in month and distributed differently in the Yellow River irrigation area.But it was conversely steady in central arid zone and mountainous area of southern Ningxia.The probability of single abundant precipitation year was higher than single short precipitation year and the continuous short precipitation year was higher than continuous abundant precipitation year.The main cycles were 3a,6a and 10a approximately.In the mid arid zone and the mountainous area of southern Ningxia,the probability of precipitation reduction was about 75% and the Yellow river irrigation area,71.4%,respectively.The reduction in the entire area was about 73.3%.The annual precipitation in the middle arid area and irrigation area was increasing.The variability would change slowly for the intra-annual distribution of precipitation.Especially,the reduction tendency rate in the middle arid area reached 100.0%.[Conclusion] The study provided references for the effective utilization of the local precipitation,and the coordinated development of the regional social economy and ecological environment.
文摘针对主动配电系统(active distribution system,ADS)中间歇性电源和负荷的不确定性问题,基于多场景技术提出一种两步优化调度模型。首先分析了ADS中各单元的概率模型,其次采用拉丁超立方抽样及样本缩减技术得到各单元的样本,进而构建了研究场景。在此基础上兼顾供电公司利益、污染物排放等目标,引入可中断负荷等相关约束,提出一种包含日前调度和实时调度的主动配电系统两步优化调度模型,并分别利用基于动态交换和密度距离的混沌粒子群算法和二进制粒子群算法求解日前调度和实时调度模型,算例结果表明所提模型和算法的有效性和正确性。
文摘传统的电网可靠性评估采用固定不变的元件年均故障率模型,难以适应电力系统短期风险评估需求。电网故障与灾害性天气具有较强的时间相关性,气象灾害具有明显的季节性特征,因此电网风险也具有时间波动性。在描述电网元件故障参数时,需要从原来的一维横向连续时间下的年均值模型,拓展到考虑历史同期(纵向)时间和导致故障的因素,特别是外部气象环境因素,以便更准确地描述时间及环境相依的电网故障率。在传统年均值模型的基础上建立了不同时间尺度、不同气象灾害类型下的元件故障模型,并依据此模型进行电网可靠性评估。按照该方法对西南某省级电网近3年内500 k V输电线路的故障数据进行了分析,对该电网的可靠性进行了评估。计算结果表明,不同时间段电网的可靠性指标与年均值相比具有较大差异,验证了时空环境相依的可靠性评估的必要性。
文摘作为能源技术与互联网信息技术相融合的产物,能源互联网的构建离不开大型数据服务中心互联的支撑。然而,当前互联网数据中心(Internet Data Center,IDC)巨大能耗所带来的成本和环境压力,突显出对IDC能耗管理的重要性。文中基于实时电价和多电力市场构成的能源互联网市场环境,在考虑IDC散热成本、碳排放成本以及服务延迟约束的基础上,以IDC负荷周期内总的能耗成本最小化为目标,建立了IDC数据负荷在多时空尺度下的优化调度模型,并采用反馈分支定界算法对模型求解。最后,通过算例仿真验证所提方案的正确性,仿真结果表明该技术可以显著降低IDC的能耗成本。
