城市建设 城市配电网合环分析系统的研究

城市配电网作为连接电力系统与用户的桥梁,对城市的供电质量和可靠性具有至关重要的影响。然而,在城市配电网运行过程中,由于各种原因可能出现合环现象,即回路中存在多个电源供电同一负荷或多个负荷被单一电源供电的情况。合环可能导致电网过载、电流过大、设备损坏等问题,严重影响了电网的稳定运行和设备寿命。因此,合环问题的分析和解决成为保障城市配电网安全运行的重要环节。本文主要分析关于城市配电网合环分析系统的研究。

辐射型中压配电网合环分析系统的设计与研究

分析和评估合环操作对辐射型中压配电网所造成的影响对配电网的调度和安全运行有着重要的意义。首先对某城市的典型中压配电网络进行研究,在其配电网原有SCADA/EMS和GIS系统上,提出适合于该配电网特点的合环操作分析系统的解决方案,采用基于IEC 61970/61968的公共信息模型(CIM)进行合环操作分析系统和原有系统之间的数据交换。合环潮流计算是合环操作分析系统的核心,本文采用叠加原理对合环潮流进行计算,使计算具有良好的收敛性,满足了系统在线运行的要求。

典型配电网合环潮流计算与分析

本文首先推导了合环潮流的通用计算公式,并针对不同类型的配网合环,给出了合环潮流的实用计算公式。结合配网合环的实际情况,对这些公式进行分析和简化,分析结果用PSASP软件进行仿真验证,得到了不同合环方式下,合环回路参数对合环潮流的影响,为调度人员快速判断、计算和减小合环潮流提供了理论依据。

计及负荷等值阻抗的配电网合环转供电分析模型

配电网合环转供电已经成为转移负荷的常用手段,配电网合环模型是进行合环分析的关键。现有的合环转供电分析模型大都忽略负荷阻抗,会导致合环电流的计算出现较大偏差。该文考虑负荷对合环稳态及暂态过程的影响,基于馈线首末端少量微型同步相量测量装置(μPMU)的实时量测信息对负荷进行等效处理,提出计及负荷等值阻抗的合环转供电分析模型。在该模型的基础上,利用叠加原理对合环稳态电流与冲击电流的计算进行了详细分析,针对目前求解合环冲击电流所存在的不足,提出基于最佳频率法求解合环冲击电流的一种有效方法。基于PSCAD/EMTDC仿真软件搭建具体的算例模型,验证了该文所提模型与计算方法的有效性。

配电网合环操作环流分析系统的开发和应用

双向供电网络在电力网络结构中的普遍化 ,促使配电网的合解环操作成为电力系统运行操作中必不可少的环节。苏州地区电力结构复杂 ,合环操作频繁 ,对此开发了苏州地区配电网合环操作分析系统。文中介绍了该系统的研制过程和系统特点 ,对配电网合环计算模型及计算结果的误差进行了分析 ,并对系统的前景做了展望。该系统已在苏州供电局现场投运。

基于智能电网调度控制系统的配网合环操作研究分析

为保障电网安全运行,必须对配网线路合环时冲击电流大小进行详细分析和先验计算。目前国内外一般采用建立等值模型方式进行计算,其模型构架,参数设置等均与实际电网存在一定偏差,且无法对当前潮流情况进行考虑,同时该类方法对网架结构复杂的电网不能进行有效分析,因此无法满足实际需求。本文基于智能电网调度控制系统(D5000)配网合环计算分析功能,能够实现任一规模电网下的配网合环电流实时计算,提高了电网抗风险能力,当出现紧急状况时,能为配网合环操作提供理论依据和应对措施。建立10kV线路合环操作跨110kV、220kV电压等级两种典型模型,计算合环稳态电流和瞬时最大冲击电流,同时与实际测量值进行对比分析,验证该功能的计算的准确性和实用性。

配网电磁合环倒电分析系统(GRS/D)的设计与应用

介绍接驳于SCADA系统的配网电磁合环倒电分析系统(GRS/D)。在确保电网与设备安全运行的前提下,其通过潮流计算和分析确定不同电源的两条线路间是否具备环网倒电条件,大大提高城市配网的供电可靠性。

多器官功能障碍综合征患者外周血单个核细胞内PPARγ和COX-2的关系

目的:探讨多器官功能障碍综合征(MODS)患者外周血单个核细胞(PBMC)中PPARγ与COX-2的关系。方法:收集MODS患者60例(分为三组各20例,MODS1组APACHEⅡ评分0~10分,MODS 2组11~20分,MODS 3组评分>20分及正常对照组(20例健康对照者)。确诊后分别于1d、3d、6d取静脉血,采用逆转录聚合酶链反应检测PPARγ、COX-2的表达与同期健康对照组进行比较分析。结果:①正常组PBMCs中PPARγ、COX-2表达量均较少。与正常组比较,MODS1组PPARγ、COX-2表达均明显增高,随治疗时间推移,PPARγ表达明显增高(P<0.05),而COX-2的表达则明显降低(P<0.05)。MODS2组、MODS3组PPARγ的表达低于正常对照组,随着治疗时间的增加,PPARγ明显下降(P<0.05);COX-2的表达高于正常对照组,随着治疗时间的增加,COX-2明显升高(P<0.05)。②相关结果分析表明:PBMCs中PPARγ与COX-2的表达在MODS1组,MODS2组,MODS3组呈负相关性(MODS1组:P<0.01;MODS2组:P<0.01;MODS3组:P<0.01,在正常对照组无明显相关性(P>0.05)。结论:PPARγ可能通过抑制COX-2的表达对MODS患者起到保护作用,为PPARγ内源性配体用于临床MODS的防治提供依据。

Shot noise analysis on corrosion behavior of zinc alloy (ZnAl4Cul) under dry-wet cycles

The corrosion behaviors of zinc alloy （ZnAl4Cul） in 3.5% （mass fraction） NaCl, 7.3% （mass fraction） Na2SO4 and simulated acid rain solutions were investigated using electrochemical measurements. The potential noise during dry-wet cycle was monitored and analyzed by fast Fourier transform （FFT）, fast wavelet transform （FWT）, shot noise theory and stochastic theory. Cumulative probability curves of event frequency fn indicate that the corrosion events in the dry cycles are greater than those in the wet cycles. Uniform corrosion was observed in the NaCl solution compared with more localized corrosion in the Na2SO4 solution, which is evidenced by FWT and SEM. Conditional events generation rate r（t） for diffusion controlled reactions decreases with increasing the time. r（t） values for uniform corrosion and diffusion controlled process are the largest in the wet cycle in 3.5% NaCl solution. The values of r（t） for pitting corrosion in Na2SO4 solution are observed to become large during spraying periods, and r（t） for pitting corrosion has the largest value in the Na2SO4 solution. The intergranular corrosion of zinc is serious in simulated acid rain solution.

Analysis of the sealing performance of combined sealing structure under deep-sea high pressure environment

For the requirement of safe and stable operation,the combined sealing structure was used for reciprocating motion in the deep sea high-pressure environment,and the effects of different seawater depths and shaft movement speed on the sealing performance of the combined sealing structure were studied.The change rule of the sealing performance of the combined sealing structure of reciprocating motion under different working conditions is proved.The study shows that in the combined sealing structure of reciprocating movement,the Von Mises stress and the contact stress of the O-ring varies with the direction of the shaft movement.The Von Mises stress and contact stress of the O-ring,the Von Mises stress and the contact stress on each sealing lip of the slip ring gradually increase with the increasing of seawater depths.At the same time,the Von Mises stress of the O-ring which in the process of the shaft upward movement is greater than the shaft downward movement,making the shaft upward movement more likely to cause the O-ring relaxation and fatigue.The shaft movement speed has no significant influence on the Von Mises stress and contact stress of the O-ring.The research results provide theoretical guidance and technical support for the selection and optimization of the geometrical parameters of the combined sealing structure in the deep-sea high-pressure environment.

Kinetic-Thermodynamic Analysis of the Reactive Distillation Process of the Cyclohexene Hydration Using the Zeolite Catalyst

Reactive distillation could be utilized to produce cyclohexanol through the cyclohexene hydration. By means of highly active zeolite catalyst HZSM-5, the kinetic-thermodynamic analysis of this reactive distillation has been carried out to get the characteristics of the reactive distillation. Results from kinetic and thermodynamic analysis indicate that the optimal pressure of this reactive distillation process should be set to higher pressure such as 0.3 or 0.4 MPa. To avoid the recovery of cyclohexanol at the top of the column, an unreactive section should be allocated at the upper column. In addition, the inert component benzene is more unfavorable to the reactive distillation process in comparison with the inert cyclohexane.

Preparation and Spectroscopic Study of Different Stoichiometric Solid Supramolecular Inclusion Complexes of β-Cyclodextrin with Short Chain Aliphatic Amines

The solid Supramolecular complexes of β-cyclodextrin （β-CD） with ethylenediamine 1, diethylenetriamine 2 and triethylamine 3 were obtained and characterized using elemental analysis, powder X-ray diffraction, infrared spectroscopy, thermogravimetric analysis, and ^1H nuclear magnetic resonance spectroscopy. Based on the results of elemental analysis and ^1H NMR, the guest-host stoichiometries of the three solid complexes were determined to be 5：2 for 1-β-CD, hl for 2-β-CD, and 1：3 for 3-β-CD. The yields were relative to the molar volume ratio of guest to β-CD cavity, and increased in the order： 1-β-CD〈2-3-CD〈3-β-CD. X-ray diffraction patterns of the inclusion complexes gave very good exhibitions not only in location of diffraction peaks but also in shape and diffraction intensity of the peaks due to the intermolecular complexations between β-CD and the guests. The formation of host-guest inclusion complexes exhibited obviously enhanced phase change temperatures of the complexed guests such as 1 and 3. The H-5 protons located at the narrower rim inside the CD cavity experienced a higher shift upon inclusion while all other protons experienced lower shifts.

Theoretical Studies on the Structure and Spectrum of Imidazole-Chloranil Charge Transfer Complex

UV-Vis absorption spectra of the molecular complex formed by imidazole （Ira） and chloranil （CA） were measured in chloroform. The stoichiometry of the imidazole-chloranil （hn-CA） complex was determined as 1：1 by applying Benesi-Hildebrand＇s equation and Job＇s continuous variation method. Density function theory （DFT） and MP2 calculations were performed to study the structures and the binding energies of the Im-CA complex. The calculations located four conformations （denoted as S1-S4） for the Ira-CA complex, two edge（Im）-to-face（CA） linked and two edge（Im）-to-edge（CA） linked. It was found that the edge-to-face conformers are more stable than the edge-to-edge ones. The bonding characteristics of these conformers were investigated with natural population analysis （NPA）, topological analysis of electron density, and natural bond orbital （NBO） analysis. It was revealed that the edge-to-face conformers are charge-transfer （CT） complexes whereas the edge-to-edge conformers are the hydrogen bond complexes. For the most stable conformation of the Ira-CA complex （S1）, the charge transfer interaction of the imidazole n（N15） lone pair orbital with the chloranil π＊ （C1=O7） orbital plays a crucial role in the Ira-CA binding, and the binding is further strengthened by the O7… H2O hydrogen bond. The electronic excitation energies of the complex （S1） were calculated with time-dependent DFT （TDDFT）, and the observed UV-Visible spectrum of the complex was analyzed based on the computed results.

Extraction and Crystal Structure of Karounidiol

The title compound of karounidiol (C30H48O2), a main active triterpene component of snakegourd seed, was isolated from unsaponifiable matter of the seed oil of Trichosanthes kirilowii Maxim., and characterized by X-ray diffraction analysis. It crystallizes in orthorhombic system, space group P212121 with C30H48O2CH3OHH2O (C31H54O4), a = 7.515(1), b = 14.407(1), c = 27.799(2) , V = 3009.8(5) 3, Z = 4, Dx = 1.087 g/cm3, Mr = 490.77, F(000) = 1088 and = 0.086 mm-1. The final R = 0.0840 and wR = 0.2289 for 2752 observed reflections (|F|2 ≥ 2|F|2). The molecular crystal structure of karounidiol shows relative stereochemistry of (3,13,14, 20)-3,29-dihydroxy-13-methyl-26-norolean-7,9(11)-diene. The molecule is composed of five six- membered rings with ring junctures of A/B trans, C/D trans and D/E cis.

PF/EP/Nano-SiO_2 Composite Paint for Resistor

Phenolic resin(PF) and nano-SiO2 were used to improve the curing property and high humidity resistance of epoxy resin (EP) and methyl nadic anhydride (MNA) resistor paint, respectively. Hydrogen bonds, formed between phenolic resin and nano-SiO2 in alcohol, made nano-SiO2 disperse easily in EP/MNA paint through phenolic resin without being treated by supersonic vibration. When the mass ratio of PF to EP in paint is 3:7, the formed composite paint film can be cured in 2 min at 170 ℃ . When the mass ratio of nano-SiO2 to PF in paint is 3:100, the property of high humidity resistance of the composite paint is the best, meeting the requirement of varying ratio of resistance less than 0.1% after experiment on high humidity resistance. SEM analysis shows the surface of the composite paint film is smooth, glassy, tight and homogeneous, without acicular air holes.

Performance analysis of a zeotropic mixture(R290/CO_2) for trans-critical power cycle

Low critical temperature limits the application of CO_2 trans-critical power cycle.The binary mixture of R290/CO_2has higher critical temperature.Using mixture fluid may solve the problem that subcritical CO_2 is hardly condensed by conventional cooling water.In this article,theoretical analysis is executed to study the performance of the zeotropic mixture for trans-critical power cycle using low-grade liquid heat source with temperature of200℃.The results indicated that the problem that CO_2 can't be condensed in power cycle by conventional cooling water can be solved by mixing R290 to CO_2.Variation trend of outlet temperature of thermal oil in supercritical heater with heating pressure is determined by the composition of the mixture fluid.Gliding temperature causes the maximum outlet temperature of cooling water with the increase of mass fraction of R290.There are the maximum values for cycle thermal efficiency and net power output with the increase of supercritical heating pressure.

Synthesis and Crystal Structure of 2-Chloromethyl-1H-benzimidazole Nitrate, [ClCH_2(C_7H_6N_2)]NO_3

The title compound [ClCH2(C7H6N2)]NO3 has been prepared and characterized by elemental analysis and X-ray studies. It crystallizes in the monoclinic system, space group P21/n with a = 7.4189(3), b =15.3064(6), c = 9.2657(3) ? b = 102.449(2)? C8H8ClN3O3, Mr = 229.62, V = 1027.44(7) 3, Z = 4, Dc = 1.484 g/cm3, F(000) = 472, = 0.363 mm-1, R = 0.0671 and wR = 0.1546. The crystal structure consists of discrete 2-chloromethyl-1H-benzimidazole cations and NO3- anions. The benzimidazole ring with the conjunction carbon atom C(1) is fairly planar, with the deviation from the least plane through the ring atoms is smaller than 0.010(3) ? The analytical results of crystal structure show that three different non-covalent interactions in the compound, NH…O intermolecular hydrogen bonds, CH…O interaction and p-p stacking interaction, play an important role in the crystal packing.

基于业务流的智能分析与辅助决策系统应用

智能分析与辅助决策系统(ADS)是构建在SCADA/EMS系统之上的电力系统智能分析和控制软件的通称。是对现有的调度分析控制功能的扩展,主要侧重调度员的实际应用,使电网调度由目前的"人工分析型"上升为"智能分析型"。系统可有效提高调度运行人员驾驭电网及防御电网运行风险的能力,缩短事故处理时间,大幅度地提高供电可靠性。现有的智能分析与辅助决策系统包含的功能模块很多,但彼此之间相互独立。本文结合调度员的日常操作将智能分析的各模块集成到调度员的日常操作中,可以使智能分析与辅助决策系统最大限度地发挥作用。

Clarifying the relationship between PM2.5 and ozone complex pollution and synoptic patterns in a typical petrochemical city in the Bohai Rim region of China:Implications for air pollution forecasting and control

Meteorological conditions are vital to PM_(2.5)and ozone(O_(3))complex pollution.Herein,the T-mode principal com-ponent analysis method was employed to objectively classify the 925-hPa geopotential height field of Dongying from 2017 to 2022.Synoptic patterns associated with four pollution types-namely,PM_(2.5)-only pollution,O_(3)-only pollution,Co-occurring of PM_(2.5)and O_(3)pollution,Non-occurring of PM_(2.5)and O_(3)pollution-were characterized at different time scales.The results indicated that synoptic classes conducive to PM_(2.5)-only pollution were“high-pressure top front”,“offshore high-pressure rear”,and“high-pressure inside”,while those conducive to O_(3)-only pollution were“offshore high-pressure rear”,“subtropical high”,and“high and low systems”.The Co-occurring of PM_(2.5)and O_(3)pollution were influenced by high pressure,and the Non-occurring of PM_(2.5)and O_(3)pollution were linked to precipitation and strong northerly winds.The variation in dominant synoptic patterns is crucial in the frequency changes of the four pollution types,which was further validated through the analysis of typical cases.Under the favorable meteorological conditions of high-pressure control with strong northerly winds or a subtropical high and inverted trough both with strong precipitation,there is potential to achieve coordinated control of PM_(2.5)and O_(3)in Dongying.Additionally,measures like artificially manipulating local humidity could be adopted to alleviate pollution levels.This study reveals the importance of comprehending the meteorological factors contributing to the formation of PM_(2.5)and O_(3)complex pollution for the improvement of urban air quality in the Bohai Rim region of China when emissions are high and the concentration of air pollutants exhibits high meteorological sensitivity.

Analysis of emergy-based metabolic efficiency and environmental pressure on the local coupling and telecoupling between urbanization and the eco-environment in the Beijing-Tianjin-Hebei urban agglomeration

We use emergy-based urban metabolism analysis in this study to investigate the local coupling and telecoupling between urbanization and the eco-environment in the Beijing-Tianjin-Hebei urban agglomeration. Our analysis encompasses the last 35 years spanning the period between 1980 and 2014. In addition, we analyze urban metabolic efficiency and environmental pressure in these couplings. There are three main conclusions of this study. First, we show that the total metabolic emergy value of the Beijing-Tianjin-Hebei urban agglomeration has increased over the last 35 years, and that external elements have replaced internal ones as the leading contributors to urban metabolism in this region. The proportion of metabolic emergy derived from external elements increased from 30.87% in 1980 to 67.43% in 2014. The emergy extroversion ratio has continued to increase over our study period, while the development of this urban agglomeration had become progressively and more heavily reliant on external elements. Second, over the study period, the metabolic emergy intensity of elements of local coupling and telecoupling in the Beijing-Tianjin-Hebei urban agglomeration has declined at an accelerating rate, from 1.15×10^(21) Sej/100 million RMB in1980 to 9.69×10^(19) Sej/100 million RMB in 2014. This reflects a continuous increase in the economic efficiency of this area.Correspondingly, emergy use per capita increased from 7.8×10^(15) Sej/person in 1980 to 5.83×10^(16) Sej/person in 2014, suggesting a gradual rise in the level of social welfare in this urban agglomeration. However, we also observed a consistently elevated environmental loading ratio(ELR) in our analysis in terms of metabolism of local coupling and telecoupling elements. This result indicates that environmental pressure has also increased constantly within the Beijing-Tianjin-Hebei urban agglomeration. Third,our analysis shows that the ELR of metabolic emergy from internal elements increased from 8.30 in 1980 to 43.46 in 2014, while the ratio from external elements increased from 4.15 to 92.03. Thus, we quantitatively investigated the dependency of development within this urban agglomeration on external elements as well as the resultant environmental load. The conclusions of this study provide the basis for quantitative policy-making in the Beijing-Tianjin-Hebei region, optimizing economic structures, improving economic efficiency, controlling environmental pollution, and promoting the coordinated development of this region.