共查询到20条相似文献,搜索用时 828 毫秒
1.
2.
1新能源电动汽车充电对电网产生的影响1.1电网峰值增加近年来,在国家大力提倡下,新能源电动汽车市场占有率越来越高,与此同时新能源电动汽车因缺乏合理性的规范管理,出现了无序充电的行为。在新能源电动汽车无序充电的情况下用户的用电波动较大,会导致接入负荷侧的结构更加多元化,使得电网系统出现尖峰值,负荷峰谷差的情况日益加重,尖峰负荷的波动会逐步复杂,涌现出许多的非线性和不可控性问题,在某段时间内出现的用电高峰期会造成整个电网的负荷加剧。 相似文献
3.
4.
三相负荷不平衡对低压线损的影响 总被引:4,自引:0,他引:4
网改后农村低压电网结构发生了很大的变化,电网结构薄弱环节基本解决,供电能力大大增强,电压质量明显提高,大部分配电台区的低压线损率降到了11%以下。但仍有个别配电台区因三相负荷不平衡等原因而造成线损率居高不下,给基层供电所造成较大的管理困难,下面针对这些情况进行分析和探讨。 相似文献
5.
6.
对于区域性独立电网,电源结构配置与负荷特性的差异,新能源快速发展,带来系统较大的调峰压力.对区域性电网光伏接纳总量进行测算,对指导光伏企业投资具有重要意义,同时可为政府、电网对光伏项目批准提供重要参考. 相似文献
7.
新型电力系统背景下,分布式光伏发展迅速,对配电系统的光伏接纳能力提出更高要求。与城市配电系统相比,农村配电系统网架弱、供电线路长、负荷多但小而分散,分布式光伏规模化接入显著增加了电网运行风险,光伏消纳能力有限,严重阻碍农村光伏的进一步开发,提升新型农村配电系统的光伏消纳能力迫在眉睫。随着乡村振兴战略的实施,农村配电系统中空调、采暖与电动汽车等灵活负荷不断涌现,给利用负荷消纳光伏提供了可能。在对柔性负荷可调度特性建模研究现状进行分析的基础上,结合现有配电系统光伏电站、电池储能系统与电动汽车充电站规划的研究现状,对提高农村配电系统光伏消纳能力的光-储-充规划方法进行了展望。 相似文献
8.
近几年来 ,农网售电量占我局总售电量的 50 %以上 ,而且农村用电市场还在不断扩大 ,从而开拓农网迫在眉睫。农网建设与改造是国家为拉动农村经济增长 ,减轻农民负担所采取的基础设施建设项目 ,它不仅关系到国家建设资金的有效使用 ,而且有利于国民经济持续、稳定、快速的发展 ,同时可以改造不合理的电网结构 ,加强电网供电能力 ,提高人民生活水平 ,为我地区经济发展起到重要保障和促进作用。供电能力的提高 ,可以发展更多的电力用户和负荷。随着科学技术进步和人民生活水平提高 ,对电压质量、线损和力率等主要经济技术指标的要求越来越高。… 相似文献
9.
10.
11.
12.
13.
14.
15.
《Journal of Agricultural Engineering Research》1998,69(3):249-254
A model to represent the discolouration of dried powder of carrots as a function of temperature was developed. Two types of carrots, Asian and European, containing large amount of lycopene and β-carotene, respectively, were tested. The dried powder was stored under an atmosphere with O2and at three different temperatures, 5,20 and 35°C. The surface colour of the powder was monitored during storage by a Hunter colour ratioa/b. In the proposed model, the rate of oxidation was assumed to be represented by the product of the fraction of concentration of oxidized pigment at arbitrary time and a specific rate of oxidation of pigment. The rate parameters in the proposed model were calculated by fitting the experimental data with smooth curves by trial and error at the end of the induction period but before discolouration took place. The frequency constant and activation energy, expressing the temperature dependence of the rate parameters, were expressed by the Arrhenius relation. The simulation results of a Hunter colour ratioa/bof dried powder at 25°C showed good agreement with the experimental data, suggesting that the proposed model was effective for the prediction of discolouration of dried powder of both types of carrot. The use of the induction period in the manner described may enable the shelf life of dried powder to be predicted. 相似文献
16.
17.
18.
The fractional outflow rate of water from the rumen, measured as the rate of disappearance of the chromium complex of ethylenediamine tetra-acetic acid, was related to a number of dietary factors. A multiple regression equation was derived which expressed fractional outflow rate as a function of the intakes of dry matter, ash, acid-detergent fibre and crude protein.The data analysed consisted of 243 observations for sheep on 59 diets, including forage, concentrate and mixed diets. The ranges covered by the data were: fractional outflow rate 0.7–3.6 day?1; dry matter intake 560–1400g/day; ash 4–30%, acid-detergent fibre 7–41%, crude protein 5–26 % of dry matter; there were no observations for sheep of less than 34 kg liveweight.The equation accounted for 56·3 % of the total variance. Between-sheep variance could not be calculated for the whole of the data but was undoubtedly substantial since, for a sixth of the data, it was known to account for 38 % of the total variance. 相似文献
19.
感官检验棉花的品级,这是农村常见的一种检测手段.它的一个主要特点就是存在不确定性.这是由于检验员的品级检验水平存在一定的差异,其中有很多因素制约着检验的结果.文章对影响感官检验结果的因素进行了系统的分析. 相似文献
20.
从灾害经济学的角度探讨了城镇供水优化调度的必要性和可能性,认为在缺水不可避免的情况下,对供水进行优化调度可以减小缺水带来的损失,产生较好的减灾效益,特别是可以大大减小严重干旱的灾害效应。并根据水资源的特性,提出了缺水损失的计算模式以及优化调度的原则和方法。 相似文献