针对光伏并网下母线的电压和频率波动提出了四项评价指标即影响系数、离散度、偏度和最大波动率。关于配电网的谐波含量提出了两项评价指标,即谐波平均总畸变率和谐波总畸变率合格率。对配电网的网络损耗提出了系统网损的改善系数和网...针对光伏并网下母线的电压和频率波动提出了四项评价指标即影响系数、离散度、偏度和最大波动率。关于配电网的谐波含量提出了两项评价指标,即谐波平均总畸变率和谐波总畸变率合格率。对配电网的网络损耗提出了系统网损的改善系数和网损率变化率两项评价指标,然后应用变异系数法求解各项指标的权重,并结合逼近理想解的排序方法(Technique for order preference by similarity to ideal solution,TOPSIS),形成了一套完整的光伏并网评价体系。最后将所提评价体系应用于评估河南省某地区的光伏接入方案,以选取其最优接入方式。展开更多
Drought is one of the severe natural disasters to impact human society and occurs widely and frequently in China,causing considerable damage to the living environment of humans.The Yellow River basin(YRB)of China show...Drought is one of the severe natural disasters to impact human society and occurs widely and frequently in China,causing considerable damage to the living environment of humans.The Yellow River basin(YRB)of China shows great vulnerability to drought in the major basins;thus,drought monitoring in the YRB is particularly important.Based on monthly data of 124 meteorological stations from 1961 to 2015,the Standardized Precipitation Evapotranspiration Index(SPEI)was used to explore the temporal and spatial patterns of drought in the YRB.The periods and trends of drought were identified by Extreme-point Symmetric Mode Decomposition(ESMD),and the research stages were determined by Bernaola-Galvan Segmentation Algorithm(BGSA).The annual and seasonal variation,frequency and intensity of drought were studied in the YRB.The results indicated that(1)for the past 55 years,the drought in the YRB has increased significantly with a tendency rate of-0.148(10 a)^(-1),in which the area Lanzhou to Hekou was the most vulnerable affected(-0.214(10 a)^(-1));(2)the drought periods(2.9,5,10.2 and 18.3 years)and stages(1961–1996,1997–2002 and 2003–2015)were characterized and detected by ESMD and BGSA;(3)the sequence of drought frequency was summer,spring,autumn and winter with mean values of 71.0%,47.2%,10.2%and 6.9%,respectively;and(4)the sequence of drought intensity was summer,spring,winter and autumn with mean values of 0.93,0.40,0.05 and 0.04,respectively.展开更多
文摘针对光伏并网下母线的电压和频率波动提出了四项评价指标即影响系数、离散度、偏度和最大波动率。关于配电网的谐波含量提出了两项评价指标,即谐波平均总畸变率和谐波总畸变率合格率。对配电网的网络损耗提出了系统网损的改善系数和网损率变化率两项评价指标,然后应用变异系数法求解各项指标的权重,并结合逼近理想解的排序方法(Technique for order preference by similarity to ideal solution,TOPSIS),形成了一套完整的光伏并网评价体系。最后将所提评价体系应用于评估河南省某地区的光伏接入方案,以选取其最优接入方式。
基金supported by the Henan Province Scientific and Technological Project (Grant Nos. 162102410066 & 172102410075)the National Key Research and Development Plan (Grant No. 2016YFC0401407)the open research fund of the State Key Laboratory of Simulation and Regulation of Water Cycle in River Basin at the China Institute of Water Resources and Hydropower Research (Grant No. IWHR-SKL-201701)
文摘Drought is one of the severe natural disasters to impact human society and occurs widely and frequently in China,causing considerable damage to the living environment of humans.The Yellow River basin(YRB)of China shows great vulnerability to drought in the major basins;thus,drought monitoring in the YRB is particularly important.Based on monthly data of 124 meteorological stations from 1961 to 2015,the Standardized Precipitation Evapotranspiration Index(SPEI)was used to explore the temporal and spatial patterns of drought in the YRB.The periods and trends of drought were identified by Extreme-point Symmetric Mode Decomposition(ESMD),and the research stages were determined by Bernaola-Galvan Segmentation Algorithm(BGSA).The annual and seasonal variation,frequency and intensity of drought were studied in the YRB.The results indicated that(1)for the past 55 years,the drought in the YRB has increased significantly with a tendency rate of-0.148(10 a)^(-1),in which the area Lanzhou to Hekou was the most vulnerable affected(-0.214(10 a)^(-1));(2)the drought periods(2.9,5,10.2 and 18.3 years)and stages(1961–1996,1997–2002 and 2003–2015)were characterized and detected by ESMD and BGSA;(3)the sequence of drought frequency was summer,spring,autumn and winter with mean values of 71.0%,47.2%,10.2%and 6.9%,respectively;and(4)the sequence of drought intensity was summer,spring,winter and autumn with mean values of 0.93,0.40,0.05 and 0.04,respectively.
