特高压与超高压电网间地磁感应电流的相互影响研究

电网地磁感应电流影响因素多、情况复杂,考虑各电压等级电网的参数特点,以往的GIC地磁感应电流计算集中在电网最高电压等级线路。交流特高压电网建设使我国电网增加了1 000 k V电压等级,综合考虑线路参数、变压器类型等GIC影响因素,准确计算包括500 k V超高压及1 000 k V特高压的多电压等级电网的GIC是重要研究课题。根据我国500 k V和1 000 k V实际电网的参数,并考虑线路走向等因素的影响,假设了一个特高压多电压等级电网,并建立了其GIC全节点模型。计算了两种感应地电场情况下500 k V电网、1 000 k V电网、500 k V和1 000 k V双电压等级电网的GIC,比较了三种情况电网的GIC计算结果。研究了不同电压等级电网GIC的相互作用及电网结构的影响。结果表明,1 000 k V电网GIC与500 k V电网GIC相互影响明显,在特高压电网GIC计算中,既不能在计算最高电压等级电网GIC时忽略次级高压电网的影响,也不能忽略对次级高压电网GIC的治理。     

地磁感应地电场时频变换快速计算方法

随着我国特高压输电线路的建设,我国电网建设遭受地磁感应电流（geomagnetically induced current , GIC）影响的风险将大大增加。基于大地电阻模型利用有限元计算地磁扰动感应地电场（geomagnetic disturbance, GMD）地电场的方法,建模复杂,利用有限元法计算感应地电场成本过高。地磁测深数据得到的视电阻率综合反映了大地的电性结构,文中提出基于视电阻数据及地磁台实测数据直接计算GMD地磁感应地电场的方法。仿真实验表明,该方法可以极大缩短计算时间,减小计算成本,对我国电网应对地磁暴侵害提供了有效算法。计算结果表明地磁暴对各地地电场的影响不均匀,与当地的地质电性结构有很大的关系,同时南北走向的电网将产生更大的GIC,更易受到地磁暴的侵害,应作为主要的关注对象。     

磁暴扰动对长距离输电高压系统电压影响分析

提出了分析长距离输电系统电压对磁暴感应地电场大小、方向敏感性的方法。首先建立了变电站接地磁感应电流计算模型,指出了输电线路走向、接地点间的距离和接地点间的相对位置之间的关系。然后通过计算地磁感应电流所产生的变压器集群无功损耗,分析变压器无功需求对系统电压影响。最后建立了系统电压越限指标与磁暴感应地电场大小与方向的灵敏度模型。以西北750 kV系统为例,仿真分析了地电场幅值从1 V/km～10 V/km、方向从正东(0°)到正西(180°)时750kV系统电压分布状况和电压越限指标,结果表明采用本文方法可以反映长距离输电系统节点电压对地电场大小及方向的敏感性。     

长距离输电系统电压对磁暴感应地电场敏感性研究

提出了分析长距离输电系统电压对磁暴感应地电场大小、方向敏感性的方法。首先建立了变电站接地磁感应电流计算模型,指出了输电线路走向、接地点间的距离和接地点间的相对位置之间的关系,然后通过计算地磁感应电流所产生的变压器集群无功损耗,分析变压器无功需求对系统电压影响,最后建立了系统电压越限指标与磁暴感应地电场大小与方向的灵敏度模型。以西北750kV系统为例,仿真分析了地电场幅值从1V/km~10V/km、方向从正东(0?到正西(180?时750kV系统电压分布状况和电压越限指标,结果表明采用本文方法可以反映长距离输电系统节点电压对地电场大小及方向的敏感性。     

不同电压等级电网GIC水平的比较研究

太阳磁场变化产生的地磁感应电流(GIC)直接损伤电力设备,威胁电网的运行安全.阐述了电网GIC的成因、影响以及损伤电网设备的本质,给出了不同电压等级电网GIC水平的监测数据和计算数据,比较研究了电网GIC水平和影响因素,分析了我国未来电网的灾害风险和灾害防治问题.     

磁暴在单回交流输电线中的感应电流的验证计算

准确计算磁暴期间交流电网中的地磁感应电流(geomagnetically induced current,GIC)对评估磁暴对交流电网的影响至关重要。在研究磁暴对交流电网的影响时所应用的现有模型的基础上,以单回交流输电线为研究对象,将交流输电线、接地体和大地进行统一建模;并采用有限元法(FEM)进行求解。这种新模型既可以处理电导率复杂分布的大地模型,又可以将交流输电线及接地体对地表感应地电场分布的影响考虑在内。均匀选取磁暴期间地磁场变化频率0.000 1~0.1 Hz之间的特定频点,分别采用现有模型和新模型计算交流输电线中的GIC,通过对比验证,表明现有模型在频率0.000 1~0.1 Hz之间计算磁暴期间交流电网中GIC时是适用的。     

磁暴在单回交流输电线中感应电流的验证计算

准确计算磁暴期间交流电网中的地磁感应电流(geomagnetically induced current,GIC)对评估磁暴对交流电网的影响至关重要。在研究磁暴对交流电网的影响时所应用的现有模型的基础上,以单回交流输电线为研究对象,将交流输电线、接地体和大地进行统一建模;并采用有限元法(FEM)进行求解。这种新模型既可以处理电导率复杂分布的大地模型,又可以将交流输电线及接地体对地表感应地电场分布的影响考虑在内。均匀选取磁暴期间地磁场变化频率0.000 1~0.1 Hz之间的特定频点,分别采用现有模型和新模型计算交流输电线中的GIC,通过对比验证,表明现有模型在频率0.000 1~0.1 Hz之间计算磁暴期间交流电网中GIC时是适用的。     

特高压等级及输电方式的选择

从空气间隙绝缘特性、大气条件对放电电压的影响等方面论述了特高压输电电压等级的选择问题、以及特高压交直流输电方式的特点。考虑到高海拔、重污秽等特殊问题,1 000kV作为我国特高压交流输电电压等级是比较合理的选择。     

基于感应滤波的高压取电装置谐波抑制方法

为了解决偏远山村、通信基站、郊区工厂等负荷的供电问题,通过特制的大容量电压互感器(PT)可实现从高压铁塔或架空线路直接取电,从而实现灵活取电、就地供电的要求。取电装置的负荷中,含大量非线性负荷,而取电装置直接接入高压输电线路,必然在线路中注入一定的谐波。以110 k V输电线路的单相PT取电装置为对象,考虑接入负荷类型及容量,提出了一种基于感应滤波的高压取电装置谐波抑制方法。首先对110 k V输电线路单相PT取电装置的引下线及塔型布置方案、谐波源负荷情况进行分析,建立相应的仿真模型,得到取电装置注入电网的谐波含量与取电装置容量的关系,进而确定取电装置接入电网的容量限值。分析了基于感应滤波的单相PT取电装置的拓扑及等效电路,并推导了输出电压与输入电压的传递函数,设计了感应滤波绕组和调谐装置的参数。仿真结果表明感应滤波及其调谐装置对不同谐波成分均有良好的衰减效果。可见,利用感应滤波对取电装置进行谐波抑制能减小取电装置接入对电网的影响,具有良好的经济性和技术性。     

灾害空间天气对我国电网安全的影响及风险

通过对第23太阳周几次磁暴期间广东岭澳500 kV电网的地磁感应电流（GIC）实测数据,2010年西北陕、甘、青、宁750 kV电网GIC的计算结果,以及500～1 000 kV电网结构特点和1859年超级磁暴强度的分析,阐述了极端空间天气对我国未来特高压、大规模电网安全的可能影响,提出了应对极端空间天气的研究建议。 ［     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

Lower Paleozoic oil relationships within Williston Basin, Canada

The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.     

An Analysis of Catherine＇s Character——Wuthering Heights

Wuthering Heights, Emily Bronte＇s only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.     

Features of Women's language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

Characterization of Ordovician carbonate reservoirs, southeastern Saskatchewan, Canada

The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3～4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰～ -7.8‰, PDB) and matrix dolomites (-6.6‰～ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084～0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078～0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.     

Design and analysis of generic LBS application developing platform

Location based services is promising due to its novel working style and contents.A software platform is proposed to provide application programs of typical location based services and support new applications developing efficiently. The analysis shows that this scheme is easy implemented, low cost and adapt to all kinds of mobile nework system.     

橡胶颗粒沥青混合料低温抗裂性试验研究

以AC-13级配为基础,将橡胶颗粒代替部分集料掺入混合料中,以低温弯曲试验为评价方法对不同橡胶颗粒掺量下沥青混合料的低温抗裂性进行研究,并引入应变能密度值对混合料的低温抗裂性进行综合评价.试验结果表明:橡胶颗粒沥青混合料试件的破坏微应变均超过2 300,满足冬寒区的技术指标;无论是否掺加橡胶颗粒,随着温度的下降,沥青混合料破坏时的最大弯拉强度增大,弯拉应变降低,劲度模量增大;弯曲应变能密度在胶粒掺量为1%左右时具有较大的弯曲应变能密度值,此时橡胶颗粒沥青混合料具有较好的低温抗裂性.     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

Quantitative trait loci （QTLs） for quality traits related to protein and starch in wheat

Quality traits in wheat （Triticum aestirum L.） were studied by quantitative trait locus （QTL） analysis in a recombinant inbred line （RIL） population, a set of 131 lines derived from Chuan 35050 × Shannong 483 cross （ChSh）. Grains from RILs were assayed for 21 quality traits related to protein and starch. A total of 35 putative QTLs for 19 traits with a single QTL explaining 7.99-40.52% of phenotypic variations were detected on 10 chromosomes, 1D, 2A, 2D, 3B, 3D, 5A, 6A, 6B, 6D, and 7B. The additive effects of 30 QTLs were positive, contributed by Chuan 35050, the remaining 5 QTLs were negative with the additive effect contributed by Shannong 483. For protein traits, 15 QTLs were obtained and most of them were located on chromosomes 1 D, 3B and 6D, while 20 QTLs for starch traits were detected and most of them were located on chromosomes 3D, 6B and 7B. Only 7 QTLs for protein and starch traits were co-located in three regions on chromosomes 1D, 2A and 2D. These protein and starch trait QTLs showed a distinct distribution pattern in certain regions and chromosomes. Twenty-two QTLs were clustered in 6 regions of 5 chromosomes. Two QTL clusters for protein traits were located on chromosomes 1D and 3B, respectively, three clusters for starch traits on chromosomes 3D, 6B and 7B, and one cluster including protein and starch traits on chromosome 1D.     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.