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41.
分析实现永州电力通信交换网集中操作和维护的必要性,介绍了实现程控交换机远程操作和维护的两种方式,总结在实践过程中所得到的经验和教训。 相似文献
42.
对T形线路的故障测距,现有方法都是先判断故障支路,再将3端线路等效成2端线路进行测距。但在 T节点附近短路,尤其是经高阻短路时,现有的测距方法由于无法正确判别故障支路而存在一定范围的测距死区。针对上述缺陷,分别假设故障发生在某一支路,由假定正常的2段支路端的电压、电流推算求得 T节点电压和注入假定故障支路的电流,从而分别求得3个故障距离。经证明,求得的3个故障距离有且仅有1个在0和对应支路总长度之间,该距离就是真实的故障距离,故障发生在对应支路上。该方法无需事先判别故障支路即可测距,在 T节点附近经高阻故障时无测距死区。其测距精度理论上不受过渡电阻和故障类型影响,无需故障前数据,且对滤波无高要求。EMTP仿真结果表明该方法正确、有效,测距精度高。 相似文献
43.
地方热电联产企业发展对策的探讨 总被引:2,自引:2,他引:0
介绍了泰州热电企业的运行情况,分析了各热电厂在技术改造、扩大热用户和强化内部考核管理方面的措施,探讨了地方热电企业应采取的对策和发展思路。 相似文献
44.
I. A. Chaban 《Journal of Superconductivity》1996,9(1):33-42
The impurity mechanism proposed earlier is used to interpret the magnetic properties of hightemperature superconductors. The appearance of superconductive granules and the existence of weak bonds in grains of ceramics and in single crystals is explained. The irreversibility line is obtained and its new interpretation as the line of thresholds of appearance of infinite nonsuperconductive cluster is given. The relaxation time of the magnetic susceptibility in alternating magnetic fields is calculated. The decrease of the Meissner fraction with increase in magnetic field and decrease in doping, and other magnetic properties are explained. 相似文献
45.
Manabu Ishitobi Takeshi Myoi Koji Soshin Eiji Hiraki Mutsuo Nakaoka 《Electrical Engineering in Japan》2005,153(3):79-87
This paper presents a single lossless inductive snubber‐assisted ZCS‐PFM series resonant DC‐DC power converter with a high‐frequency high‐voltage transformer link for industrial‐use high‐power magnetron drive. The current flowing through the active power switches rises gradually at a turned‐on transient state with the aid of a single lossless snubber inductor, and ZCS turn‐on commutation based on overlapping current can be achieved via the wide range pulse frequency modulation control scheme. The high‐frequency high‐voltage transformer primary side resonant current always becomes continuous operation mode, by electromagnetic loose coupling design of the high‐frequency high‐voltage transformer and the magnetizing inductance of the high‐frequency high‐voltage transformer. As a result, this high‐voltage power converter circuit for the magnetron can achieve a complete zero current soft switching under the condition of broad width gate voltage signals. Furthermore, this high‐voltage DC‐DC power converter circuit can regulate the output power from zero to full over audible frequency range via the two resonant frequency circuit design. Its operating performances are evaluated and discussed on the basis of the power loss analysis simulation and the experimental results from a practical point of view. © 2005 Wiley Periodicals, Inc. Electr Eng Jpn, 153(3): 79–87, 2005; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20126 相似文献
46.
47.
Present-day power systems operate with high reliability, and it is rare that a blackout will extend over an entire system swiftly and securely. This paper considers automatic power supply to loads after a complete blackout of a system. First, taking into account characteristics of generators, loads, and initial power sources, a method is proposed of allocating several generators to each load in parallel to the system and supplying power to the load sequentially. Second, to remove the imbalance between supply and demand of power, a method is proposed of adjusting the amount of supply and generation according to a present imbalance and the sum of past ones. Third, to automatically issue orders for start-up, parallel, follow-up, stand-by, and stoppage of generators, several rules for each power station are set and an expert system is made based on them. Finally, the expert system is applied to a model power system, and it is verified that it can restore loads without any trouble for a complete blackout which occur at any time of a day and in any restoration pattern. 相似文献
48.
C. Llopis F. Revents L. Batet C. Pretel I. Sol 《Nuclear Engineering and Design》2007,237(18):2014-2023
The Technical University of Catalonia (UPC) has been jointly working with the Asociación Nuclear Ascó-Vandellòs (ANAV) for a number of years in order to establish, qualify and use best estimate (BE) models for the reactors under the control of ANAV. ANAV is the consortium that is responsible for operation of the Ascó and Vandellòs-II reactors. The reactors are Westinghouse-design three-loop PWRs with an approximate electrical power of 1000 MW. The existing integral plant models for each plant are currently used for many different purposes among which are support of plant operation and control. Quite a number of studies have been done in order to improve both safety and plant competitiveness. Most of these dynamic analyses were carried out in relation to transients starting at nominal full power or at least, very close to full power. This paper develops a specific use of the Vandellòs-II plant model for operation and control support at low power involving new ranges of system actuation parameters. It also examines scenarios that are somewhat different from those typically analysed. The study starts showing the results of an assessment case, which is a start-up test and provides some additional qualification, and subsequently attempts to establish calculations to support both an improvement in feed water controls and to set up operating recommendations for low-load manual operation of feed water turbo-pump. Both results hopefully, will produce an outcome, which leads to an improvement in safety and reduces reactor trip probability. 相似文献
49.
介绍了城市轨道交通直流牵引供电系统的构成,详细叙述了直流牵引供电系统的主要电气设备及其连接方法,以及系统的运行方式.另外,还简单介绍了系统配置的直流保护以及保护原理和保护作用. 相似文献
50.
LIU Li xinEngineer Design Institute Changjiang Water Resources Commission Wuhan China CHANG Han junEngineer Design Institute Changjiang Water Resources Commission Wuhan China 《人民长江》2001,(Z1)
1 OverviewTheGeheyanPowerStationhasfourcircularinlettun nels,ontherightbankofdamsite,withtheirexcavationdi ameterof 11.3mto 12.5m,after liningdiameterof 9.5m,axis to axisspacingof2 4m.Thethicknessofpillarsareequaltothetunneldiameter.Theintakecenterisateleva ti… 相似文献