THE ECONOMIC DISPATCH OF REAL POWER WITH SECURITY

This paper presents an approach to studing the economic dispatch of real power with N-1 security with the network flow programming (NFP), the N-1 line - security constraints are first introduced into the network f olw model and the problem of N-1 security economic dispatch becomes an incremental metwork flow model. Therefore, the shortage of NFP is mitigated to some extent, The solution adopted is the "out-of-kilter"algorithm(OKA), which is characterized by fast calculation and reliable convergency. The model and solution are tested on IEEE 30-bus system, and the results show that the proposed approach is feasible.     

APPLICATION OF OUT-OF-KILTER ALGORITHM TO ECONOMIC DISPATCH WITH SECURITY

This paper reports on the application of "Out-of-Kilter Algorithm" (OKA) to the real power economic dispatch with security constraints. The network flow programming is characterized by simple manipulation, fast and reliable convergence, while the OKA can treat nonzero lower bounds and may initiate with any set of flows (including infeasible flow) which satisfies Conservation of flow. The major procedure and numerical example of OKA are given in this paper. The calculating results for economic dispatch on test systems have shown that the method is feasible and effective.     

AUTOMATIC CONTINGENCY SELECTION AND RANKING USING AN UNIFIED MODEL AND ALGORITHM FOR P - AND Q - SUBPROBLEM

A new approach of the automatic contingency selection and ranking with the network flow programming (NFP) is presented in this paper. NFP is adaptable to change the network topology as the transmission or generation branches arc in single or multiple outage. Thus the fast calculation of the contingency states by NFP cm provide the urgent information in real time N- 1 security analysis. In the paper, automatic contingency selection and ranking forP- and Q-type subproblem arc solved by an unified network flow model and algorithm. It is based on the existence of weak coupling between real and reactive quantities in power systems. The performance indices to assess the severity of contingencies are defined as the total real and reactive load required to be curtailed. The proposed ACS technique including the model and its algorithm are examined with IEEE 5-, 14-, 30-, 57- and 118- bus test systems on M-340. And the encouraging results are given in the paper.     

APPLICATION OF A CONVEX NETWORK FLOW PROGRAMMING TO THE ECONOMIC POWER DISPATCH

Analyses the characteristics of convex network flow programming of the economic power dispatch with security and presents a rapid algorithm. The numerical examples are given to demonstrate the effectiveness of the algorithm.     

AN APPLICATION OF ANALYTIC HIERARCHY PROCESS TO AUTOMATIC CONTINGENCY SELECTION AND RANKING

This paper presents an approach to study the problem of automatic continency selection and ranking with the analytic hierarchy process, and takes into consideration the relative importance of transmission lines and the situation that the real and reactive power security constraints are violated as the line outage appears. Thus, the precise information in the real time security analysis and economic dispatch can be provided.     

A HIERARCHICAL CONTROL METHOD FOR REACTIVE POWER OPTIMIZATION IN LARGE-SCALED INTERCONNECTED POWER SYSTEMS

This paper presents a new hierarchical and coordinative control method for reactive power optimization in large-scale interconnected power systems. It combines the interconnection forecast method for hierarchical control in large-scale steady state industrial systems with the incremental linear programming method for reactive power optimization in real time. The results of applying the method to power system examples show that the method not only solves the problem of high dimension in order, but also keeps the advantages of the incremental linear programming method. The proposed method is also suitable for the security analysis of reactive power correction in large-scale interconnected power systems.     

Application of Linear Programming in the Steady-State Real Power Security Region

This paper presents a new rnethod for analysis and computation of steady-statereal power security region by linear programming.In this method based on the D.C load flow,theupper and lower bounds of the hyper-cuboid explicit steady-state security region are chosen asunknown variables.The objective function is the total amount of the adjustable generations withweighting factors.The model of the steady-state real power security region is changed in to the proposed linearprogramming methed for ealculation.The numerieal exarnples are tested on IEEE 6-bus and 30-bussample systems.The computational resuIts showed the proposed model a nd algorithm feasible andeffective.     

A preventive control model for static voltage stability considering the power constraints of weak branches

The voltage instability of power system often occurs when the active power on one or more weak branches exceeds its transfer capability. A preventive control model for static voltage stability is proposed using the active power transfer capability of weak branches as static voltage stability constraints. A local line based voltage stability index is used to determine the critical contingencies, weak branches and transfer capability of each weak branch. A static security analysis method, which is based on DC power flow equations, is used to establish the non linear active power flow expressions on weak branches following each critical contingency. The active power constraints on weak branches can be obtained from the active power flow expressions and transfer capabilities of weak branches. A quadratic optimal model for preventive control including the proposed active power constraints on weak branches is presented. The simulation results for IEEEE14 bus system and IEEE118 bus system demonstrate the correctness and effectiveness of the proposed preventive control model.     

THE APPLICATION OF NETWORK PROGRAMMING METHOD ON THE SHORT TERM OPTIMAL SCHEDULING FOR CASCADED HYDROPOWER STATIONS

The problem of the short term economic scheduling for cascaded hydropower stations is discussed with the network programming method. A new network model is built to dispatch the load to each unit when the unit commitment is determined. An algorithm of the minimal cost maximal flow is also discussed using the model and the algorithm to the Longxi River Cascaded Hydropower Stations, the computational result on the microcomputer VAX II shows that the model and the algorithm are correct and applicable.     

AUTOMATIC CONTINGENCY SELECTION AND RANKING BY NETWORK PROGRAMMING APPROACH

This paper presents a new approach ,to the automatic contingency selection and ranking by the network flow programming (NFP). A complex cost optimisation model based on economy and security, and several simplified models are proposed in the paper. The performance index is the total load curtailment or its weighted value. All the solution algorithms are OKA. The model and its algorithm is tested on IEEE 30-Bus System and the encouraging results are obtained.     

OPTIMAL REACTIVE POWER FLOW BY SENSITIVITY METHOD

A new approach based on sensitivity method for the optimal power flow is presented in the paper. This method has the following advantages: it is suitable to solve a 200-node power system on the microcomputer; the convergence is easy to reach and the computation speed is quick; it is possible to reduce 8-14% power loss and to get maximum economic benefit by using this method; in power system dispatch center it can be used as an on-line voltage and reactive power control program to keep good voltage level. The proposed method has been proved successful by IEEE 118-node test system and the several real power systems such as 49-node, 61-node, 99-node and 200-node systems.     

Web System Development Model Based on Access Security MVC

In order to reduce the inconvenience of maintainability and reusability of web application system based on MVC, which is brought by the code of access security and coupling tightly with other modules, A web system development model based on access security MVC is put forward. The main framework and running process are provided and the key techniques of this model are researched. The model is applied to the practical development of the network distribution management system.     

A DECOMPOSED OPTIMIZATION MODEL FOR POWER NETWORK PLANNING

This paper presents a decomposed optimization model for power network planning. The planning problem is divided into master problem to determine the investment decisions and subproblems to deterimne the operation decisions. In the proposed model, the effects of multi load levels,stochastic line outages,power loss cost and load curtailment cost on the investment decisions are considered. The results of the examples prove the feasibility and effectiveness of the proposed model.     

Design on Contingency Classifier of Functioned Link Neural Network

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.     

Vehicles Scheduling Decision Support System

Under traffic conditions and vehicle capacity constraints, in view of commercial grou Plarge-scale vehicles Scheduling question characteristic, it proposes a solution framework. First, the customers are segregated into districts. Then the customer districts are assigned to vehicles using the vehicle scheduling model and heuristic algorithm. Third, the vehicle mutes are determined as a Traveling salesman problem. With the solution framework and by taking the a Chongqing commercial grou Pas the case, the authors designs the decision support system.     

Research on Cooperative Design Network Security Based on IP-VPN

As the important method and instrument of agile manufacture,the technology of distributed collaborative design and manufacturing has become the hotspot of manufacturing. The basic concept and key technologies of IP_VPN are introduced in this paper,and a collaborative design network model based on IP_VPN is presented. Distributed collaborative design is a multi_user,multitask involved system, which is consisted of lots of collaborative processs,so the network security is the key of distributed collaborative design. We research on the security of collaborative design network based on IP_VPN, hence get a conclusion:we can construct an economical?practical and secure collaborative design network system by the application of data encryption,user authentication and access control based on the role,etc.     

THE DECOUPLJNG CALCULATION OF MULTI-AREA POWER SYSTEM LOAD FREQUENCY CONTROL

The calculating burden of the decoupling judgement of multi-area power system load frequeney centrel is very large by tranditional methods. This paper changcs the decoupling judgement problem into a minimum cost network flow problem. The solution algorithm is out-of-kilter . algorithm which is characterized by simple manipaultion, fast and reliable convergence. In the paper, we discuss and calculate the decoupling problem of two arca power system load frequency control. The results show that the proposed approach is feasible and effective.     

中国耕地资源安全模式识别的PNN神经网络方法

耕地资源安全不仅事关中国的粮食安全,而且影响中国的生态安全和社会安全。为了分析各地区耕地安全的特点和影响因素,笔者首先选取评价指标,构建区域耕地资源安全风险评价模型,然后应用安全预警理论建立耕地安全风险评价指标阈值标准,最后利用PNN神经网络模型,对中国区域耕地风险进行分析。结果表明,中国耕地安全风险分为5类地区：高度危险区：四川、云南、内蒙古、福建、重庆、陕西、贵州、甘肃、青海,主要是生态脆弱区;危险地区：山东、北京、上海、天津、广西;值得关注地区：宁夏、江苏、浙江、西藏、广东,既有经济发达地区又有相对落后地区;安全区：辽宁、山西、河南、河北;高度安全区：安徽、湖南、湖北、新疆、海南、江西、吉林、黑龙江,安全和高度安全区中,大部分是中国的粮食主产区。这意味着中国耕地保护政策要转向耕地生态背景和质量的保护,经济发展对耕地资源的压力也不容忽视,同时要继续加强对粮食主产区耕地保护的倾斜政策,确保中国的粮食安全。     

Trust management scheme based on community model for mobile Ad hoc networks

The security issues in mobile Ad hoc network, especially caused by inner malicious nodes are analyzed. By tracking the behavior of nodes, trust level of each node can be evaluated and managed; then actions of malicious nodes will be constrained and the security and reliability of entire network are enhanced. According to the features of Ad hoc. The scheme proposed in not only extends the conception of trust but also include the trust computation model and trust management mechanism. Simulation experiments show the novel scheme is more efficient than other trust schemes in traditional protocols.     

Simulation method for multi-machine and multi-task crane scheduling in steelmaking plant

It is of great significance in steel complex to link production flow between work stations and control production rhythm by cranes. Crane scheduling is a multi-machine multi-task problem which limits temporal and spatial constraints and production plan. A simulation model based on evolution rules to solve temporal and spatial constraints is proposed. Its objective is to guarantee execution of production plan in steelmaking plant. And match between cranes and production task on working span is conducted to fulfill temporal constraints between multi-tasks and spatial constraints among multi-cranes. Simulation rules including task allocation, conflicts eliminating and task finishing are also proposed to dominate simulation process. This model avoids difficulties of theoretical calculation for crane scheduling problem. Offline test in a steelmaking plant shows that it is available to make a crane scheduling without conflicts between cranes and plans, which provides a guideline for production scheduling.