Reliability Evaluation for Bulk Power System Including Dependent Outage of Transmission Line

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.     

Transmission Congestion Management Based on Power Influence Coefficient

Basing eliminating on the idea that the generator who has the most influence on the power flow of line is mostly in favor of transmission congestion, the model of congestion management with the object of minimizing adjustments of bufions varied with generation outputs is proposed. It can eliminate the congestion effectively by judging the generators who should be adjusted and the amounts of adjustment. The test on IEEE-RTS24 buses system and other practical systems show that the proposed method is effective.     

从输电阻塞角度建立的风电场容量可信度模型

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。     

AN A. C. LOAD FLOW ANALYSIS OF THE RELIABILITY EVALVATION OF COMPOSITE GENERATION AND TRANSMISSION SYSTEMS

An A. C. load flow analysis of the reliability evaluation of composite generation and transmission systems is presented on the basis of a fast outage simulation algorithm and an optimal model of active and reactive power adjustment after outage contingencies. The information of the first -level outage events is utilized for simulating higher -level outage events in the fast outage simulation algorithm ; the optimal model is satisfactory in speed and accuracy with the application of concentric relaxation and linear increment constraint on the comprehensive adjustment of active and reactive power. As an example. the IEEE Reliability Test System is tested and the results show that the method is accurate and well-matched in speed with the method studied by R. Bllinton, et al.     

A reliability evaluation model for photovoltaic/diesel hybrid power generation system

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.     

Load Curtailment Strategy by Near in Bulk Power Systems Reliability Evaluation

In order to improve the existing method of electric network reliability evaluation, the basic concepts, for example, the flow through the failure events, the sent ends and received ends of these failure events, the load curtailment region of the received ends and the degree of the load curtailment, are defined. With these concepts, the connotation of LCSN (Load Curtail Strategy by Near) is enriched and algorithms of the load curtailment region are conducted. The theory foundation for further exploring LCSN is created. The results show that the algorithm can quickly and effectively make reliability assessment of power systems.     

Optimal Load Curtailment in Bulk Power System Reliability Evaluation

This paper studies the question for considering optimal load curtailment in bulk power system adequacy evaluation. A minimization model of load curtailment is utilized for the contingency states which may have load curtailment. In order to calculate realistic bus indexes, two practical load curtailment philosophies are incorporated in the minimization model of load curtailment, which is achieved in computer program developed for bulk power system reliability evaluation. The minimization model of load curtailment, correlated algorithms, and flow chart of program are given in this paper. The effectiveness and availability of the model are verified from two case studies.     

电网可靠性评估的网络静态等值模型分析

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。     

Power Model of Bond Graph and Dynamic Simulation of Hoist System for Multi-Flow Transmission

The double drive hoist reducer developed in the planetary gear is a new generation of energy saving and environment protecting hoist product. The multi flow transmission system theory of hoist is analyzed. With the theory and method of bond graph,a bond graph model with coupled vibration is established for hoist multi flow transmission system for the first time. The state equation of the system is developed and dynamic simulation analysis is also carried out. The internal changing law and relationship of the system for the state variable are got. Therefore, the dynamic properties and gearing features of this system are revealed comprehensively. The research results can provide the dynamic analysis method and design basis for multi flow transmission system of hoist.     

Development of a Novel Intellectual Transmission Line Inspection System

The power transmission line is one of the important parts of electrical power system,the management and inspection of the transmission lines have been significant routine job ensuring the reliability of the transmission system. This paper describes in detail the basic principle of the intellectual transmission line inspection system using Geographic Information System(GIS) and Global Position System(GPS) technology.This novel inspection system is composed of pocket PC,GPS receiver and management PC,and takes full advantage of modern computer and network communication technique.Owing to the advantages of high reliability,practicability and scalability,the practical application of this intellectual inspection system shows that it completely meets the requirements for fast speed,high efficiency and real-time performance.     

THE MONTE-CARLO METHOD FOR RELIABILITY EVALUATION OF LARGE SCALE COMPOSITE GENERETION-TRANSMISSION SYSTEMS

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.     

A NONLINEAR PROGRAMMING MODEL AND ITS ALGORITHM FOR TRANSMISSION NETWORK PLANNING

The problem of transmission network planning is studied thoroughly by applying the mathmatical optimal tecqhniue in this paper. A novel approach is put forward for computer aided transmission network planning, which is quite different from what is based on D.C. load flow equations. A nonlinear transmission planning model is set up by regarding A.C. load flow equations as the system model. A practical model which can be solved more easily, and an united algorithm are obtained by applying the SUMT to the nonlinear model. The results of some practical examples indicate that this method can not only make the planning results more accurate, but also provide the voltage qualities and produce planning plans autometically and seek the plans optimally and fast.     

Optimal bidding models of power plants considering transmission congestion

In order to achieve optimal bidding strategy of power plants in electricity market, the authors build optimal bidding model by predicting the bidding coefficients of competitors, and the optimal bidding coefficient without considering transmission capacity is achieved. Based on the bidding coefficients, the market clearing model is built, and the expected market clearing price is achieved. According to the expected values, the authors calculate the power flow. When forecasting the transmission congestion, this paper presents an optimal bidding model taking transmission congestion into account. Based on sensitivity analysis, the output regulation of power plants with minimum cost of eliminating congestion is achieved. Simulation results demonstrate that the proposed method can help power plants achieve the optimal profit.     

Reliability evaluation algorithm for complex electrical distribution networks using the storage structure of adjacency multilist

A section algorithm of reliability evaluation for complex medium voltage Electrical Distribution Networks (EDNs) using adjacency multilist (AM) is proposed. The constructing method for AM is introduced. The AM can be used to store the structure data of EDNs and to solve the problem of space & time complexity. A new power flow algorithm of backward / forward sweep is proposed and a fast algorithm of forming sections in distribution network is put forward. The proposed algorithm makes a perfect combination of the power flow algorithm and the section algorithm of reliability evaluation, which makes efforts to decrease the work of programming and saves the computing time. Applying the proposed algorithm in RBTS-BUS6 system and actual EDNs, the reliability assessment results show that the algorithm has an advantage of saving time and possesses efficiency in engineering practicality.     

计及电网停电风险的输电线路动态融冰决策方法

电网发生大面积冰灾情况时，多条输电线路存在覆冰故障隐患，电网稳定运行受到严重威胁，需要提前制定输电线路融冰方案，合理安排融冰顺序。针对此问题，分析输电线路覆冰继续运行给电网带来的停电风险，将与待融冰输电线路相关联的变电站的电气主接线展开，将传统削负荷模型改进后应用于输电网与变电站主接线的组合网络，建立断路器可靠性模型，计算靠后融冰线路因继续运行的电网停电风险；利用计及风速及降雨影响的输电线路覆冰增长预测模型，计算输电线路的覆冰率，根据覆冰率门槛值确定待融冰线路集，基于覆冰严重度模型构建系统全局的覆冰指数指标；综合考虑电网停电风险及系统全局覆冰指数建立输电线路融冰紧迫度指标，动态更新待融冰线路并决策融冰顺序。最后，以IEEE RBTS系统进行算例分析，验证了所提方法的可行性与合理性。     

Analysis on starting characteristic of continuously variable transmission system with reflux power

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.     

SHORT-TERM RELIABILITY EVALUATION FOR GENERATION SYSTEM

This paper presents an analytical method to evaluate the short-term reliability for generation system. Based on the discretization of continuous Markov Process,the transient performance of short-ferm reliability is considered, and the Loss of Load Expection(LOLE) Energy Index of Reliabihty (EIR) are calculated step by step. This method is applied to evaluate short-term rehability of a generation system,and the results of the evaluation show that the method is feasible.     

A Survey of Power Flow Tracing Algorithm

Competition in the electricity markets requires identifying the responsibility in the use of transmission networks or the associated effects. Power Flow Tracing algorithms have been developed recently to enhance the transparence of transmission system. This paper focuses on power flow tracing procedures and provides a detailed comparison of three classified algorithms: 1) power flow tracing based methods; 2) current tracing based methods; and 3) power flow analytic methods. The advantage and disadvantage of each method are discussed. Finally, the potential applications and development of the methodology is presented for furthermore research.     

Remote Test Method of Relay Protection

Considering the limitation of the field test for relay protection in power system, the paper studies and discusses the remote test method of relay protection in power system. It provides the technology requirements, the technology problems and restricted factors to build the protection test and analysis center. It proposes the method of building the protection test and analysis center. Considering the practice for the transmission of test data, the paper introduces the technology requirements of utilizing dispatching automation system data network to transmit the protection test data. Considering the requirements of microcomputer protection devices for remote test method, the paper presents that there are remote test function and synchronization test function in the field microcomputer protection devices.     

Disscussion in the Rural Power Network Construction in the New Rural Construction

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.