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湖北电网短路电流限制措施研究 总被引:1,自引:0,他引:1
随着电网规模的不断扩大,电网联系越来越紧密,湖北电网短路电流水平日益攀升,多个站点出现超标的情况,已严重影响电网的安全稳定运行,急需研究短路电流限制措施。针对当前国内外广泛应用的限制电网短路电流的措施,结合湖北电网现状及发展规划,本文对湖北电网2015年目标网架的短路电流水平进行了仿真计算,对短路电流超标的站点进行了仿真分析。分析结果表明,母线分段运行、分层分区运行、采用高阻抗变压器、采用串联电抗器、提高断路器遮断容量等短路电流限制措施,可将湖北电网短路电流有效控制在合理水平,以保障电网安全可靠供电。 相似文献
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近几年随着宁夏电网的快速发展,火电厂及新能源的大规模接入,短路电流超标问题日益突出。本文基于转移阻抗的概念,分别从电源发展和网架变化两个方面分析了2014至2018年引起宁夏电网各电压等级短路电流超标的原因,结果表明电源接入是导致330 kV、750 kV电网短路电流超标的主要原因,引起220 kV短路电流超标的主要因素是网架变化。此外分析了各电压等级火电厂的短路电流灵敏度系数,结果表明火电厂对本电压等级的短路电流灵敏度系数最大。最后总结了近年来宁夏电网已采取的短路电流限制措施,并结合宁夏电网十三五规划,分析了宁夏电网4分区运行方案。 相似文献
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±1100kV特高压直流接入后短路电流分析及限制措施研究 总被引:1,自引:0,他引:1
《高压电器》2016,(11):18-24
结合新疆电网规划发展,随着昌吉地区750 kV网架结构的延伸和大规模电源的建设,对比分析了新疆电网±1 100 kV(准东—皖南)特高压直流接入前后短路电流的增加原因与趋势。当±1 100 kV特高压直流接入昌吉五彩湾地区后,为了限制系统短路电流水平,文中从加装电抗、网架结构调整及运行方式安排等方面展开讨论分析,研究结果表明,在合理控制新疆五彩湾地区短路电流的水平下,750 kV五彩湾变电站的220 kV母线分列运行及附近大电源送出线路优化将有利于短路电流的有效控制,对解决新疆电网发展中昌吉五彩湾地区短路电流超标问题提供参考。 相似文献
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《电气》2011,(2):14-18
With the incessant development of power market reform,the existing cross-subsidy in electricity tariffs has become a critical problem in China’s power industry development.On the basis of the theories of cross-subsidy and electricity universal service,the authors take foreign countries’ experience as reference to design several solutions to cross-subsidies in electricity tariffs in different phases of China’s power industry development.Furthermore,the application and implementation of these solutions are analyzed in this paper. 相似文献
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The author suggests that the confidence which many biologists have in problem-solving methods is unwarranted and that there are very important limitations in almost all current methods for solving biological problems. The standard problem solving approach that computer scientists use is outlined. An example of an error in an evolutionary tree problem-the case of the African Eve-is discussed 相似文献
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无色透明材料形成的单层薄膜,其颜色由干涉色决定。以白光照射其表面,随薄膜厚度的增加,将出现一系列色彩,这是由薄膜干涉所致。我们可以根据薄膜颜色,估计薄膜厚度。显然,当厚度增大到后界面的影响可以忽略不计的程度(相当于只有一个界面的半无限大情形,本文简称“厚膜”),则“厚膜”颜色恢复为无色透明。半透明材料在基底上形成的薄膜系统,以白光照射所呈现的颜色,由于基底及吸收的影响,则不能简单地以薄膜干涉来分析。对于半透明薄膜系统,首先测量它的光强反射率谱和透射率谱,运用传递矩阵[1]方法计算出薄膜的介质光学常数,再以光学常数计算单层薄膜与“厚膜”的光强透射率谱与反射率谱及它们的色坐标。以菲涅耳公式计算出的反射率谱为半无限大介质反射率谱,这时的色坐标可视为“厚膜”的色坐标。 相似文献
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A survey is provided of Japanese research on ceramic materials for substrates, microwave dielectric ceramics, piezoelectric ceramics, semiconducting ceramics, and superconducting ceramics. Novel processing technologies are described, covering the use of amorphous materials, superfine powders, lamination, multilayer thin films, porous ceramics, and superlattices 相似文献
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Recent progress in inverse problems in electrocardiology 总被引:5,自引:0,他引:5
The considerable progress achieved in the inverse problem of electrocardiography over the last decade has provided grounds for optimism about the possibility of approaching significant clinically relevant applications in the next decade. However, there are a number of basic questions that still remain. In addressing these questions, the authors feel it is important to seek solutions that emphasize physiological rather than mathematical significance. This approach leads to twin requirements for useful inverse solutions: accuracy, defined in a physiologically meaningful (and not just averaged and mathematical) sense, and reliability, not only to measurement noise but also to geometric modeling errors and other uncertainties that are inescapable in practical application. Studies using analytically tractable models may still be relevant, but it seems more important to find solutions to practical inverse problems, which will move the field toward wider acceptance and credibility 相似文献
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