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1.
文章对常用的几种静止无功补偿装置作了简要的比较,进而为了利用磁控电抗器的优势,使其能够有效抑制电压波动和闪变,针对其速度慢的缺点对其进行了改进:将外延三角形接线应用于磁控电抗器的绕组接线中,根据谐波抵消原理,通过2组分别为左移和右移连接的电抗器并联来消除自身谐波,防止污染系统,同时设置饱和曲线使其没有直流控制时就可以工作在自饱和状态,提高其响应速度,拓宽磁控电抗器的应用范围。MATLAB仿真结果表明,改进后的磁控电抗器达到了抑制电压波动和闪变的目的。  相似文献   

2.
文章对常用的几种静止无功补偿装置作了简要的比较,进而为了利用磁控电抗器的优势,使其能够有效抑制电压波动和闪变,针对其速度慢的缺点对其进行了改进:将外延三角形接线应用于磁控电抗器的绕组接线中,根据谐波抵消原理,通过2组分别为左移和右移连接的电抗器并联来消除自身谐波,防止污染系统,同时设置饱和曲线使其没有直流控制时就可以工作在自饱和状态,提高其响应速度,拓宽磁控电抗器的应用范围。MATLAB仿真结果表明,改进后的磁控电抗器达到了抑制电压波动和闪变的目的。  相似文献   

3.
文章对常用的几种静止无功补偿装置作了简要的比较,进而为了利用磁控电抗器的优势,使其能够有效抑制电压波动和闪变,针对其速度慢的缺点对其进行了改进:将外延三角形接线应用于磁控电抗器的绕组接线中,根据谐波抵消原理,通过2组分别为左移和右移连接的电抗器并联来消除自身谐波,防止污染系统,同时设置饱和曲线使其没有直流控制时就可以工作在自饱和状态,提高其响应速度,拓宽磁控电抗器的应用范围。MATLAB仿真结果表明,改进后的磁控电抗器达到了抑制电压波动和闪变的目的。  相似文献   

4.
李艳丽 《科技与企业》2013,(22):300-300,302
由于电网系统中接入大量的非线性负荷所产生的谐波电流,引起电压及电流的波形畸变,严重影响供电质量,影响设备运行,造成能源浪费;抑制和治理谐波电流成为亟待解决的问题,采用电容器串联一定电抗率的电抗器组成调谐滤波器能有效地消除和抑制谐波,改善电能质量,提高功率因数,为企业节约电费。  相似文献   

5.
当前许多地区都采用并联电容器进行无功补偿,从而提高功率因数,改善系统电压,降低线损,然而为了限制合闸涌流并抑制谐波,部分变电站一般在每相电容器前串联电抗器,但是电抗器会因为许多原因发生烧毁事故,对电力系统造成威胁。文章在描述了10k V电容器串联电抗器原因的基础上,根据某变电站10k V电容器组电抗器被烧毁事故,对事故发生的原因进行了综合分析,并有针对性地提出了防范措施。  相似文献   

6.
磁控式可控并联电抗器在长距离输电中实现控制电压和补偿无功等功能,对于提高输电线路稳定性、改善供电质量具有重要的作用。为了实现磁控式可控并联电抗器的运行特性,其自动控制系统通过相应的控制模式控制磁控式可控并联电抗器的励磁系统从而控制其运行特性。  相似文献   

7.
在现代电力系统中,供电系统的无功功率与谐波消耗了大量的电力资源,文章提出要不断研究新的抑制无功功率与谐波的措施与方法,同时可以积极优化配网线路中的并联电容器以及串联电抗器的参数,采用综合的补偿技术,提高配网线路中的供电质量。  相似文献   

8.
在电力系统中,磁阀式可控电抗器对于提高电力系统稳定性、改善供电质量具有重要的作用.本文对磁阀式可控电抗器的特性进行了分析研究,并对其等效电路进行了仿真,分析了控制角与其容量的关系.  相似文献   

9.
电网系统中一般采用并联电容器-电抗器组等无源设备进行无功补偿并兼作滤波,但由于负载经常处于变化之中,采用固定容量补偿方式常常不能满足要求。通过分析磁阀式可控电抗器及动态无功补偿装置工作原理,论证了磁阀式可控电抗器在电网系统中无功补偿的优越性和可行性。以DSP和ARM数字处理器为核心,设计了MCR的控制系统,可以对电抗器的感性无功输出进行平滑的调节,从而实现动态无功补偿的目的。  相似文献   

10.
电力系统并联补偿装置中的LC串联电路   总被引:1,自引:0,他引:1  
陈春娥  张长宇 《价值工程》2010,29(34):34-35
在电力系统中,并联补偿装置可以补偿系统中的无功功率、降低网络损耗、提高功率因数和电压质量。并联电容器装置是电力系统中最常用的并联补偿装置,电容器和电抗器串联连接就构成了LC串联电路。电容器主要用于补偿系统中的感性无功,通常与系统负荷端并联连接;而为了降低电容器合闸投运过程中的涌流倍数,以及抑制电网电压波形畸变和控制流过电容器的谐波分量,还需给电容器配套选用串联电抗器。本文在讨论了LC串联电路之后,提出了与电容器配套使用的电抗器电抗率的选取方法。  相似文献   

11.
When an optimal investment decision is studied for a firm whose capital goods are subject to a delivery lag, a control problem with a time-delay argument in the objective function emerges. Such a problem under a set of simple assumptions is shown to be reducible to a two-stage optimal control problem. The significance of this is that familiar tools from standard optimal control theory are applicable to the resulting two-stage problem. Necessary conditions are presented for a general two-stage problem with an adjustable switching time. Some specific results are also obtained for several special cases.  相似文献   

12.
Several studies have used ordinary least squares (OLS) to estimate school district expenditure functions for states with closed-end matching aid. The present paper demonstrates that the estimates of these studies may be inconsistent. A two-stage technique which guarantees consistent estimates is described and is used to estimate the price elasticity of expenditure for Pennsylvania school districts. The two-stage estimates indicate expenditure to be substantially more price-elastic than do the OLS estimates. The two-stage technique is appropriate for estimating any input demand or expenditure function when closed-end matching aid is involved.  相似文献   

13.
Dr. B. F. Arnold 《Metrika》1986,33(1):93-109
Summary In order to compare two sampling plans we use the minimax regret principle, i.e. the minimax principle applied to regret functions. It is shown that among all two-stage sampling plans there exists an optimum sampling plan which can be computed with the aid of a procedure presented in this paper; furthermore another procedure is described how to obtain an approximately optimum two-stage sampling plan in a more direct way. Finally only those two-stage sampling plans are regarded which satisfy an additional condition; among these sampling plans an optimum one exists and is to be determined, too.  相似文献   

14.
A two-stage analogue of the Ftest for one-way analysis of variance is proposed. Critical values are given for selected cases and the method of obtaining critical values is described. Comparisons of the one-stage and two-stage tests are made in terms of the expected sample size required to achieve a given power.  相似文献   

15.
A class of partially generalized least squares estimators and a class of partially generalized two-stage least squares estimators in regression models with heteroscedastic errors are proposed. By using these estimators a researcher can attain higher efficiency than that attained by the least squares or the two-stage least squares estimators without explicitly estimating each component of the heteroscedastic variances. However, the efficiency is not as high as that of the generalized least squares or the generalized two-stage least squares estimator calculated using the knowledge of the true variances. Hence the use of the term partial.  相似文献   

16.
陈荣  李月  章大海 《价值工程》2009,28(3):81-85
以单点区域型配送中心选址为研究对象,以系统理论、组合理论等为基础,运用定量、定性方法对区域型配送中心选址进行研究,提出了新的选址方法——两阶段单点选址法。借助Matlab等软件的强大功能,进行计算求解,并通过实例验证了该方法的有效性。  相似文献   

17.
This paper studies a two-stage procedure for estimating partially identified models, based on Chernozhukov, Hong, and Tamer’s (2007) theory of set estimation and inference. We consider the case where a sub-vector of parameters or their identified set can be estimated separately from the rest, possibly subject to a priori restrictions. Our procedure constructs the second-stage set estimator and confidence set by taking appropriate level sets of a criterion function, using a first-stage estimator to impose restrictions on the parameter of interest. We give conditions under which the two-stage set estimator is a set-valued random element that is measurable in an appropriate sense. We also establish the consistency of the two-stage set estimator.  相似文献   

18.
A two-stage procedure based on the statistic introduced by Scheffé (1943) to solve the Behrens-Fisher problem is considered in estimating the difference between the mean values of two normal distributions having unequal and unknown variances. Samples of unequal size are considered at each stage. A numerical example is given where the two-stage procedure is compared with the Satterthwaite (1946) approximate method.  相似文献   

19.
王桂强  李紫东  刘兴 《物流科技》2007,30(12):26-29
论文探讨了交通线路可能被敌方毁坏情况下的车辆路径优化问题,建立了不确定的两阶段整数规划数学模型,分析了路径方案的最大和最小效用值。在线路方案评价值的计算中只计算最小值和最大值,简化了方案的目标值计算。设计了求解模型的双层禁忌搜索算法。最后通过应用示例验证了模型和算法的有效性。  相似文献   

20.
Several limited-information type estimators of the nonlinear simultaneous equation model are considered and their asymptotic covariance matrices are compared. Amemiya (1974) proposed the general class of nonlinear two-stage least-squares estimators. In this paper, its two specific members are considered and, in addition, the nonlinear limited-information maximum- likelihood estimator and the modified nonlinear two-stage least-squares estimator are proposed. Both are shown to be asymptotically more efficient than the nonlinear two-stage least-squares estimator, and the second has the advantage of being computationally simple.  相似文献   

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