官亭变电站750kV高压并联电抗器运行状况分析

官亭变电站750kV2＃电抗器是国内目前运行电压等级最高的一组高压并联电抗器。分析了750kV高压电抗器在官亭变电站的运行情况和技术监督数据：技术监督数据稳定，油色谱分析数据良好，继电保护和安全自动装置无动作，电抗器整体运行状况良好。提出了未来改造计划：重新建造3台电，抗器的基础，将目前的条形基础改为方形基础，增强电抗器的底部支持面，放弃现在使用的千斤顶；制造一台新的电抗器，替换运行中的电抗器B相。     

750 kV官亭变电站电抗器局部振动超标分析及处理措施探讨

750kV官亭变2号电抗器2005年9月投运以来。局部振动超标问题一直存在。厂家对2号电抗器的减振采取了底部支撑的方法．但不能从根本上改变电抗器的振动超标问题。通过对官亭变电站750kV2号电抗器实施3次减振措施并对前后振动数据进行分析,认为2号电抗器减振的最佳方法是采用铁芯的5处压紧及止退系统和油箱对器身的强力定位及其他减振措施。     

变压器绝缘油在线监测技术在750 kV变压器中的应用

介绍了官亭变电站变压器绝缘油在线监测系统的原理、结构和应用情况.分析了在线色谱数据,结果表明官亭变电站750 kV变压器运行正常.     

世界海拔最高的750kV输变电工程成功投运

2008年11月30日,世界海拔最高的750kV输变电工程——官亭一西宁750kV输变电工程成功投运。官亭一西宁750kV输变电工程是国家电网公司和青海省重点建设项目之一,其中西宁750kV变电站是青藏联网工程的起点,海拔高度2630m,线路最高海拔2920m,是目前世界上同电压等级海拔最高的输变电工程。750kV主要电器设备外绝缘水平达到或超1000kV电压等级。官亭一西宁750kV输变电工程的建设和投入运行,对加快西北750kV主网架的建设步伐,     

750 kV示范工程系统调试综述

国家电网公司750kV示范工程系统调试范围为750kV官亭变电站变电工程、750kV兰州东变电站变电工程、750kV官亭变电站至750kV兰州东变电站一条140km的750kV线路。系统调试方案包括两部分:第一部分为750kV输变电示范工程系统调试方案,第二部分为750kV示范工程系统调试测试方案。本文详细叙述了系统调试方案中的试验项目和试验内容;并对系统调试测试项目进行了简单介绍。对系统调试结果进行了简单概括分析,并给出了系统调试结论。     

750kV示范工程系统调试综述

国家电网公司750kv示范工程系统调试范围为750kv官亭变电站变电工程、750kV兰州东变电站变电工程、750kV官亭变电站至750kV兰州东变电站一条140km的750kV线路。系统调试方案包括两部分：第一部分为750kV输变电示范工程系统调试方案．第二部分为750kV示范工程系统调试测试方案。本文详细叙述了系统调试方案中的试验项目和试验内容：并对系统调试测试项目进行了简单介绍。对系统调试结果进行了简单概括分析，并给出了系统调试结论。     

750 kV官亭变电站GIS特快速暂态过电压测试

官亭变电站GIS中的特快速暂态过电压（Very Fast Transient Overvohage,VFFO）测试是自西北750kV输变电示范工程2005年9月投产以来,国内首次对750kVGIS中的隔离开关进行正常带电拉合操作试验。通过本次测试,获得了大量的实测数据和典型波形,为全面掌握750kVGIS中的VFTO特性打下了基础。对官亭变电站750kVGIS中VFTO现场测试的相关情况和主要结论进行概述,并针对750kVGIS中隔离开关的倒闸操作方式提出了建议。     

西北750 kV示范工程输电线路OPGW光缆防振特性的研究

介绍了光纤复合架空地线(OPGW)光缆在国内第一个超高压西北750 kV官亭-兰州东输电线路的应用。结合西北750 kV输电线路的特点和对OPGW的要求,描述了750 kV输电线路OPGW光缆的结构设计的特点,同时通过750 kV官亭-兰州东输电线路大档距OPGW光缆防振特性的研究,为西北750 kV输电线路1 235m大档距OPGW光缆推荐了满足技术条件的直线档防振方案,并提供了测试结果及分析意见,对探索和积累750 kV超高压等级上OPGW光缆的设计和运行经验具有现实意义。     

西北750kV示范工程输电线路OPGW光缆防振特性的研究

介绍了光纤复合架空地线（OPGW）光缆在国内第一个超高压西北750kV官亭-兰州东输电线路的应用。结合西北750kV输电线路的特点和对OPGW的要求，描述了750kV输电线路OPGW光缆的结构设计的特点，同时通过750kV官亭-兰州东输电线路大档OPGW光缆防振特性的研究，为西北750kV输电线路1235m大档距OPGW光缆推荐了满足技术条件的直线档防振方案，并提供了测试结果及分析意见，对探索和积750kV超高压等级上OPGW光缆的设计和运行经验具有现实意义。     

66kV干式空心电抗器接地扁铁发热分析及处理

66 kV干式电抗器在750 kV系统电网中对消纳充电功率起着重要的作用,为了保证其正常运行,确保电力系统稳定运行,对新疆乌北750 kV变电站66 kV干式空心电抗器接地扁铁发热现象及时进行了分析,诊断发热的主要原因是在漏磁范围内存在闭合回路。通过改变连接接地支柱的方式,打开此闭合回路,解决了66 kV干式空心电抗器接地扁铁发热问题。     

超细CaO粉炉内喷射脱硫的数值模拟

在总结已有模型的基础上，考虑到CaO孔隙结构参数在反应过程中的变化，提出了CaO硫化反应的特定层数晶粒模型。通过对文献报道的实验结果和作者的实验结果进行比较，发现两者吻合较好，表明该模型预报炉内喷射超细CaO粉脱硫过程是可信的。这对于选择最佳的脱硫工况具有一定的指导意义。     

A comparative study of two H2‐redistribution strategies along the FT reactor using H2‐permselective membrane

In this study, a comparative study of two different hydrogen redistribution strategies along the Fischer‐Tropsch synthesis reactor using a Pd‐Ag membrane has been carried out. In the first strategy, fresh synthesis gas is flowing in the tube side in co‐current mode with reacting material in shell side so that the first segments of reactor use more hydrogen. In the second strategy, fresh synthesis gas is flowing in the tube side in counter‐current mode with reacting material in shell side so that last segments of reactor use more hydrogen. A one‐dimensional heterogeneous model was developed to compare two strategies from different standpoints. The model was checked using operating data of Fischer‐Tropsch synthesis reactor in pilot plant of Research Institute of Petroleum Industry in Iran. Simulation results show an enhancement in the yield of gasoline production, a decrease in undesired products formation (CO₃ and CH₄) and also a favorable temperature profile along both the configurations of membrane Fischer‐Tropsch reactor in comparison with conventional reactor. The comparison between co‐current and counter‐current configurations in terms of temperature, gasoline (C) and CO₂ yields, H₂ and CO conversions, and selectivity of components shows the reactor in the co‐current configuration operates with lower reactants' conversions and also lower permeation rate of hydrogen. On the contrary, our results demonstrated counter‐current‐mode decrease CO₂ and CH₄ as undesired products, better than other kinds of mentioned systems. Copyright © 2010 John Wiley & Sons, Ltd.     

Robust multi-objective optimization of methanol steam reforming for boosting hydrogen production

Methanol steam reforming (MSR) has been considered as a promising method for producing pure hydrogen in recent decades. A comprehensive two-dimensional steady-state mathematical model was developed to analyze the MSR reactor. To improving high purity hydrogen production, a triple-objective optimization of the MSR reactor is performed. Non-dominated Sorting Genetic Algorithm-II (NSGA-II) is employed as a robust optimization approach to maximize the three objectives, termed as, methanol conversion, CO selectivity, and H₂ selectivity. The Pareto optimal frontier has also been provided and the ultimate solution of the Pareto front has been found by the three decision-making methods (TOPSIS, LINMAP, and Shannon's Entropy). Among the three distinct decision-making approaches, LINMAP presents better results according to the deviation index parameter. It has been shown that a perfect agreement is available between the plant and simulation data. Operating under the optimum values based on the LINMAP method confirms an almost 47.04% enhancement of H₂ mass fraction compared to the conventional industrial MSR reactor. The predicted results advocate that the key superiority of the optimized-industrial reactor is the remarkable higher production rate of hydrogen compared to the conventional MSR reactor which makes optimized-industrial reactor both feasible and beneficial.     

Studies on advanced water-cooled reactors beyond generation III for power generation

China’s ambitious nuclear power program motivates the country’s nuclear community to develop advanced reactor concepts beyond generation III to ensure a long-term, stable, and sustainable development of nuclear power. The paper discusses some main criteria for the selection of future water-cooled reactors by considering the specific Chinese situation. Based on the suggested selection criteria, two new types of water-cooled reactors are recommended for future Chinese nuclear power generation. The high conversion pressurized water reactor utilizes the present PWR technology to a large extent. With a conversion ratio of about 0.95, the fuel utilization is increased about 5 times. This significantly improves the sustainability of fuel resources. The supercritical water-cooled reactor has favorable features in economics, sustainability and technology availability. It is a logical extension of the generation III PWR technology in China. The status of international R&D work is reviewed. A new supercritical water-cooled reactor (SCWR) core structure (the mixed reactor core) and a new fuel assembly design (two-rows FA) are proposed. The preliminary analysis using a coupled neutron-physics/thermal-hydraulics method is carried out. It shows good feasibility for the new design proposal.     

PWR-FBR with closed fuel cycle for a sustainable nuclear energy supply in China

From the thermal reactor to the fast reactor and then to the fusion reactor; this is the three-step strategy that has been decided for a sustainable nuclear energy supply in China. As the main thermal reactor type, the commercialized development phase of the pressurized water reactor (PWR) has been stepped up. The development of the fast reactor (FBR) is still in the early stage, marked by China experimental fast reactor (CEFR), which is currently under construction. According to the strategy study on the fast reactor development in China, its engineering development will be divided into three steps: the CEFR with a power of 65 MWt/20 MWe; the China prototype fast reactor (CPFR) with a power of 1 500 MWt/600 MWe; and the China demonstration fast reactor (CDFR) with a power of 2 500–3 750 MWt/1 000–1 500 MWe. With regards to the fuel cycle, a 100 t/a PWR spent fuel reprocessing pilot plant and a 500 kg/ a MOX fabrication plant are under construction. A project involving the construction of an industrial reprocessing plant and an MOX fabrication plant are also under application phase.     

Modeling of the oxidation of methyl esters—Validation for methyl hexanoate, methyl heptanoate, and methyl decanoate in a jet-stirred reactor

The modeling of the oxidation of methyl esters was investigated and the specific chemistry, which is due to the presence of the ester group in this class of molecules, is described. New reactions and rate parameters were defined and included in the software EXGAS for the automatic generation of kinetic mechanisms. Models generated with EXGAS were successfully validated against data from the literature (oxidation of methyl hexanoate and methyl heptanoate in a jet-stirred reactor) and a new set of experimental results for methyl decanoate. The oxidation of this last species was investigated in a jet-stirred reactor at temperatures from 500 to 1100 K, including the negative temperature coefficient region, under stoichiometric conditions, at a pressure of 1.06 bar and for a residence time of 1.5 s: more than 30 reaction products, including olefins, unsaturated esters, and cyclic ethers, were quantified and successfully simulated. Flow rate analysis showed that reactions pathways for the oxidation of methyl esters in the low-temperature range are similar to that of alkanes.     

Mathematical modelling of a hydrocracking reactor for triglyceride conversion to biofuel: model establishment and validation

In the study, a 2D, non‐isothermal, heterogeneous model of a triglyceride hydrocracking reactor is investigated. The internal heat and mass transfer within the phases in the reactor were considered using the film theory. The conservation equations for energy and mass were solved simultaneously using appropriate numerical techniques whose reliability was assessed by comparison of the results with previously reported experimental data. The modelling was performed with consideration of two proposed hydrocracking kinetic models. The model predictions showed reasonable correlation with published experimental data and conversion rates. The calculations indicated that at feed temperature of 380 °C, liquid hourly space velocity of 8 h^?1 and hydrogen : feed ratio of 1500:1, the total triglyceride conversion was 82.54% for four major classes of hydrocarbons (light, middle, heavy and oligomerised). In addition, the concentration distribution and temperature profile along the reactor were investigated. The product concentrations along the reactor show that higher rates of production at the beginning of the reactor were achieved because of high concentration of triglyceride due to the exothermic hydrocracking reactions and counter‐current flow modes of triglyceride and hydrogen; a jump of 90 °C was shown at the beginning of the reactor temperature profile. Copyright © 2014 John Wiley & Sons, Ltd.     

Neutronics and thermal hydraulic coupling analysis of integrated pressurized water reactor

In this paper, three‐dimensional (3D) power distribution of newly designed small nuclear reactor core has been achieved by using neutron kinetic/thermal hydraulic (NK/TH) coupling. This is pressurized water reactor‐based small nuclear reactor in which plate type fuel element has been used and the core of the reactor has hexagonal type geometry. This paper depicts the design of the reactor core by using coupling approach of neutronics(Neutron Kinetic) and thermal hydraulic studies. For this purpose, neutronic analysis has been obtained by using lattice physics code, i.e. HELIOS and neutron kinetic code, i.e. REMARK. HELIOS code gives the cross‐section data which is being used as input to the REMARK code. At the same time, THEATRe code was used for the thermal hydraulic analysis of the reactor core. In the coupling process, some data (fuel temperature, moderator temperature, void fraction, etc.) from THEATRe code has been used in conjunction with HELIOS and REMARK codes. After finalizing the NK/TH coupling, 3D evaluation of the power distribution of the reactor core has been achieved and is included in the paper. The purpose of this paper is to evaluate the design and get the normal operational behavior of the reactor core by NK/TH coupling approach. Copyright © 2012 John Wiley & Sons, Ltd.     

Structural integrity issues with Gen IV proposals: fast reactors and PBMR

Abstract

Structural integrity issues are discussed for two generation IV reactor concepts: the fast reactor and the high temperature reactor, more specifically, the pebble bed modular reactor. The pebble bed modular reactor and other designs of high temperature reactor are claimed to possess built-in safety features leading to safe shutdown: they do, however, involve >8% enrichment of ²³⁵U. Many high temperature creep, creep–fatigue and stress relaxation issues remain to be addressed. With lead/lead–bismuth cooled fast reactors running at ～500°C, there appear to have been none of the issues in the steam generator experienced with sodium cooling. The aspiration of both reactor types is to operate at high temperatures and to produce hydrogen from water thermochemically. A view has been expressed that temperatures up to 900°C could be achieved using metallic alloys (with ceramics for higher temperatures), but it is concluded that something of the order of 750°C represents a more realistic upper limit for economic service lives.     

Numerical analysis of operation conditions and design aspects of a sulfur trioxide decomposer for solar energy conversion

A basic concept for a receiver–reactor for solar sulfuric acid decomposition as the key step of the Hybrid Sulfur Cycle for hydrogen production has been developed and realized. A prototype reactor has been built and is specialized for the second part of the reaction, the decomposition of sulfur trioxide. For a detailed understanding of the operational behavior of the developed reactor type a mathematical model was developed. The reactor model was validated using experimental data from the test operation with a prototype reactor. The present work deals with the optimization of process and design parameters and the evaluation of the achievable performance of the reactor type. Furthermore the reactor model is used for numerical simulations to predict specific operational points of the prototype reactor and the performance of a large‐scale reactor on a solar tower. Influences of operational parameters like absorber temperature, feed mass flow, residence time and initial concentration of the acid are analyzed. In many cases those analyses reveal the existence of an optimum of reactor efficiency. When varying the absorber temperature an optimum of reactor efficiency emerges due to two compensating effects: chemical conversion increases with temperature, whereas re‐radiation losses increase disproportionately at the same time. This matches the experimental findings very well. A large‐scale tower receiver–reactor consisting of several individual modules is modeled and simulated. The main differences to the prototype system are the reduced gradients of solar flux distribution on the receiver front face and the reduced thermal conduction losses due to the presence of several neighbor modules at a comparable temperature level. This leads to higher chemical conversions and better efficiencies. Reactor efficiencies up to 75% are predicted. Copyright © 2011 John Wiley & Sons, Ltd.