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1.
In order to calculate and analyze the effect of two transmission lines in parallel on the reliability evaluation of bulk power system, a model including independent outage, common mode outage and dependent outage of these lines is deduced and a new algorithm corresponding to the model is presented. Two transmission lines in parallel including common mode outages and dependent outages can be really simulated as a multi-state component. While reliability indices are calculated, the probability and frequency of independent outage, common mode outage and dependent outage of a system failure state can be calculated at the same time, and computation complexity is reduced. The proposed model and algorithm are applied to the RBTS system, IEEE One Area RTS96 system and a real power system for reliability computation and analysis. Results show that the new algorithm is credible and validity.  相似文献   

2.
An optimal active power adjustment model is deve in this paper for hybrid AC/DC systems after outage contingencies. The objective of the model is to minimize the rejection of load when some elements are out of service, with adjustment strategy approaching practical system operation. A large number of outage contingencies are simulated when the Monte-Carlo Method is emyloyed to evaluate the system reliability, requiring fast calculation of each simulation. The model and computer method proposed in this paper satisfy such a requirment because of the application of concentric relaxation, recursive branch constraint treatment in linear programming and a direct method for B-1 matrix modification. This paper is concerned with the simplified steady state conditions of the system based on DC load-flow, which implies the reliability indices calculated are the measures about static loss of load. The results for a 14-bus hybrid AC/DC system are given.  相似文献   

3.
To adapt to the continuous improvement of rural power consumption level in the new rural construction,in particular,with the continuous development of the rural economy,the actual operation of the rural power network has emerged as the high loss of electrical power which leads to a greater cost of the electricity,lower power supply reliability,the supply voltage and frequency do not satisfiy with requirements,etc.Through analysis of a typical rural power network,from the overall planning of the transmission to distribution equipments(such as lines,transformers and reactive-load compensation devices),the author proposes some specific measures such as reducing power loss and improving the voltage quality and reliability methods.Through calculation for lines power loss rate and percent of voltage pass,the results show that the methods proposed by the author are effective.The directions to the development trend of the rural power network is given.  相似文献   

4.
The paper presents a Monte-carlo method for reliability evaluation of large scale composite generation transmission systems. The method, which possesses coputational rapidity and sufficient accuracy,is based on combining the dispersed sampling techique with the analysis approach and the optimization model of power not supplied. Because the amount of calculation increases only linearly with, the number of elements, it is specially sui- table for large scale systems. The Monte-carlo sampling draws more near the real situation than determinate state enumeration in simulating occurrence of power system outages. Also, the method can be easily generalized to involve multi-states of elements, multi-levels and stochastic distribution of loads. The results of IEEE-RTS, as example, are given and compared with ones obtained by using the other two methods.  相似文献   

5.
Component reliability parameters are of uncertainty and are affected by the component type, operation time, and weather conditions. So do the reliability indices of bulk power systems. The calculation of its probability distributions and its alteration law affected by parameters uncertainty are researched to provide practical engineering reference with exploring the impact of the parameter uncertainty on reliability assessment. The point estimate method is firstly proposed based on the two-loop Monte-Carlo simulation, and then the improved Monte-Carlo simulation is presented to enhance the calculation efficiency further. Moreover, their theories, merits and faults are explained in detail. It can be seen from the evaluation results for the RBTS power systems that the accuracy of the three methods are similar but the improved Monte-Carlo simulation has the highest efficiency, followed by the point estimate method. The IEEE-RTS 79 power system is evaluated by using the improved Monte-Carlo simulation, and the results verify its validity.  相似文献   

6.
In this paper,the reliability calculation models of water delivery pipeline system with setting up communicating tubes are studied by net decomposition method.The calculation results show that the reliability of water delivery pipeline system may be lowered or increased with increment of the communicating tube number,and the influence of reliability variety of tubulation of delivery main pipeline and T branch pipe is a sensitive factor influencing the reliability of the system.Therefore,the research results have the important leading meaning to the design,the choice of subassembly,the construction installation,maintenance management of the water delivery pipeline system,and looking for path with the biggest reliability of the system.  相似文献   

7.
Based on the reactive surplus of Chongqing 220 kV main electric power network under low water and low load, and on state of higher system voltage, a thorough research is done on voltage and reactive power of the system power network by means of calculation,analysis and experiments. A main network calculating equivalence model of power network in Chongqing is constructed. And reactive power optimizing calculation is figured out on the Chongqing power network on condition that the loss minimum of the active power network is object function. Several optimizing compensatory schemes are put forward. Based on the calculation result and the analysis of all schemes, the most reasonable and feasible optimizing scheme could be achieved. Meanwhile, the feasibility that the system voltage could be adjusted when generator operating under excitation was demonstrated. According to the experience of under-excitation operation of the same type units , it decreases the system voltage, improves Chongqing power network running performance, and strengthens the coordination and stabilization of system.  相似文献   

8.
电网可靠性评估的网络静态等值模型分析   总被引：2，自引：0，他引：2  
为缓解大电网可靠性评估的计算复杂性,采取等值参数联合概率密度分布建模的方式开展了外网静态等值研究。在常规确定性静态Ward等值技术基础上,考虑外部区域发电机和线路随机故障,通过计算各种随机故障状态下的外网等值参数,即外网等值注入功率和外网等值串联支路阻抗,基于概率密度估计技术建立了等值参数的联合概率密度分布。外网静态概率等值模型克服了常规确定性静态Ward等值技术的不足,充分计入外网等值参数的随机性,减少了电网可靠性评估计算时间的同时提高了计算精度。对两区域RBTS系统和RTS79系统研究验证了其有效性和准确性。  相似文献   

9.
The utilization of Flexible AC Transimssion System(FACTS)technology has significant impact on power system reliability performance.Series FACTS devices such as Thyristor Controlled Phase Shifting Transformers(TCPSTs) and Thyristor Controlled Series Compensators(TCSCs) can change the natural allocation of the power flow and effectively alleviate transmission congestion.Parallel FACTS devices such as Static Var Compensators(SVCs)can provide reactive power support and maintain voltage stability.So it is important to quantitatively evaluate their benefits to the power system reliability.The traditional models of the composite generation and transmission system reliability evaluation are mainly focused on conventional generation and transmission facilities.This paper researches the power flow model of TCPST and TCSC,and then presents the optimal load shedding model incorporating TCPSTs,TCSCs and SVCs and effectively incorporates them into the reliability evaluation model.The proposed method is tested on the RBTS and the obtained results show that the system reliability can be improved effectually by FACTS devices.  相似文献   

10.
The main electrical scheme of a station is principal part of power system electrical connection,and its structure not only determines whether customers can acquire enough electric energy,but also influence economical efficiency of construction and reconstruction of a station.3/2 Connection and 4/3 Connection have been widely used in large scaled station.Three groups of alternative designs are chose in the article,of which the first group is single unit connection,and the other two are combined unit connection,and in each group there are one 3/2 Connection and 4/3 Connection plan.A reliability analysis system of main electrical scheme has been applied,to compare and analyze the reliability and economical efficiency of these two kinds of connection comprehensively.The result involves adequacy,security,economical efficiency indices and sensitivity analysis of component dependability parameter of each design.The result shows both 3/2 Connection and 4/3 Connection has its own relative merits,but 3/2 Connection has well applicability: Failure rate of generation has most obvious influence on reliability of the main electrical scheme.And quantified calculation of reliability is necessary in planning and choice of main electrical scheme of station.  相似文献   

11.
The method of small parameter and setting up model of dumbbells are used to calculate the gravitational radiation of Double Satellite,and the expression of quadrupole radiation power is obtained.The calculated results is coincident with the astronomical observed results.At the same time,the method of calculation is simpler and easier than the others.The high-order gravotational radiation(higher than the octapole radiation) can be discussed with the method of small parameter,so a new method and a way is supplied for the theory calculation of the high-order gravetational radiation.  相似文献   

12.
The reliability is an important component part of research fields in power system. This paper presents an application of object oriented programming to develop reliability evaluation system of electric networks. A new approach to reliability evaluation and graph expression is proposed, and a computer aided decision making system of electric network reliability evaluation using Visual C++ 5.0 under Windows95 environment is developed. The system can provide reliability data for power system operation and plan, which is the foundation for operation and decision making. It has the characteristics of better expansibility, convenient usage, user friendly interfaces and so on.  相似文献   

13.
Reliability non-coherence components (RNC) may exist in a power system due to the effects of distribution substation connection modes, components reliability performance, load level, and other factors. Recognizing RNCs and removing them from a power system can improve system reliability. The reliability non-coherence phenomenon is analyzed and the reliability non-coherence probability, frequency and energy indices, which can describe the degree of the system reliability non-coherence feature, are proposed. Based on the reliability evaluation theory of substation configuration, recognizing technique of RNCs of distribution substation is proposed. The theoretical analysis and example show that the breaker connects high voltage buses may be the RNC when the rated capacity of one transformer can meet the load requirement, and the reliability parameters of breakers have some effects on the reliability non-coherence features of the typical substation configuration.  相似文献   

14.
Photovoltaic power generation is considered to be one of the most promising power generation forms. It is difficult to accurately assess the reliability of the photovoltaic system (PVS) for the volatility and intermittent of the light intensity. By analyzing PVS component failure modes and their impacts on PVS output power, the reliability model of PVS is built. Then the probability model of PVS output power is presented by considering both illumination uncertainty and PVS component random faults. According to the influence of components random faults outside the intentional islands on the reliability of load points inside the intentional islands, the concepts of repair zone, isolation zone and zero zone are defined. Furthermore, by considering the fail-operation of breaker and fuse, the concept for zone hierarchy is proposed, and the analytical formulas to calculate reliability indices of the load points inside the intentional islands are deduced. The application of the presented reliability evaluation model is clarified using a typical example to show the practicality and validity of the proposed approach.  相似文献   

15.
There exists imperfections of the methods for energy conservation verification of the energy efficiency retrofit projects. A new energy conservation verification method was developed by creating energy conversion correction model and four correction coefficients and three calculation formulas were involved, The four correction coefficients were outdoor weather correction coefficient, indoor environmental correction coefficient, internal load correction coefficient and performance period correction coefficient. The three calculation formulas were heating energy conversion calculation, air-conditioning energy conversion calculation and total energy conversion calculation. The energy conversion correction model was adopted to analysis the energy conservation of an office building located in Tianjin to demonstrate the reliability of the correction model and the feasibility of the verification method, and the corrected energy conversion based on consistent conditions before and after retrofit was obtained. 10.23% difference between the corrected energy conversion and the direct energy conversion exists indicating that the correction energy conversion is necessary. The energy conservation difference of 3.03% the calculation result of energy simulation software verified the accuracy of the new verification method.  相似文献   

16.
Considering on the characteristics of the transmission system and some key units of continuously variable transmission system with reflux power, a dynamic simulation model and a control strategy are established. The design method of the new continuously variable transmission system is verified by simulation. The simulation result on this continuously variable transmission system shows that the rotating speed of the driven plate can rise up rapidly during starting clutch engagement, and the sliding friction power is lower than 3 kJ which is nearly equal to one third of the friction power of the traditional vehicle.  相似文献   

17.
Along with the extensive use of power cable lines in power distribution system, the probability of fundamental frequency resonance has greatly increased. It may endanger the security operation and power supply reliability of the power system. On the basis of theoretical analysis and numerical calculations using MATLAB language combined with a real instance, it is indicated that the improper electrical parameter coordination caused by the abundance of power cable lines result in fundamental frequency current resonance, in addition, the countermeasures based on SVC to solve the problem are put forward. Further more, digital simulations have been carried out in detail based on the dynamic simulation model developed by the application of MATLAB/Simulink and its power system simulation software. Simulation results proves the effectiveness and practicability of the scheme presented.  相似文献   

18.
Contingency analysis is thekey computational issue in power system steady state security analysis and reliability calculations. This task requires a large amount of CPU time. In order to reduce effectively requirements of computationin outagesimulation ofbulk power system,a functioned link neural network (FLNN) classified model and algorithm employed to identify contingencies is presented. For the sake of gaining post-accident information of system states, a group of performance index (PI) is designed according to the performance characters relative to the changes of base case.Moreover, a neural network classifieris constructed. A varietyof the effects of PI and combinations of PI on the proposed classifieris discussed. That branch flow performance indices are better than the others is explanted. The resultsof classification by applied the FLNNclassifierto the IEEE-RTS24 show that it not only make network and algorithmsimpler, but also improvethe speed and accurate of contingency analysis.  相似文献   

19.
Equivalent linear system method is the main method of nonlinear structural system random response analysis. While it would generate big error when the results of equivalent linear system method are used to analyze the structural dynamic reliability. Through minimum mean square error principle, general nonlinear system was converted to equivalent Duffing nonlinear system, based on which the structural dynamic reliability was analyzed. The accurate steady state analytic solution of Duffing nonlinear system can be worked out by FPK equation, so it is not only convenient but also accurate to analyze structural dynamic reliability by using the equivalent nonlinear system method. It is also shown that the analysis results of equivalent nonlinear system method presented here is reliable and the calculation accuracy is higher than equivalent linear system method apparently through the example analysis.  相似文献   

20.
风电并网时既要考虑系统的可靠性又要考虑输电阻塞。目前风电场容量可信度仅从可靠性单一角度提出。为此从输电阻塞角度提出了风电场容量可信度的定义;通过Monte Carlo法建立计及元件故障(发电机、线路和变压器)的风电场容量可信度模型,并提出该模型的二分法求解算法;同时还提出了风电阻塞指标以描述风电场并入电力系统对缓解系统输电阻塞的贡献。通过对修改的IEEE-RTS进行算例分析,验证了方法的正确性和实用性。结果表明：系统阻塞状况的缓解程度与并入风电场的位置有关,风电场容量可信度和风电阻塞指标相结合可以评价风电场并网对系统阻塞状况改善的有效性和经济性。  相似文献   

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