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Power Systems, IEEE Transactions on

Issue 3 • Date Aug 1996

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Displaying Results 1 - 25 of 61
  • Application of an optimisation method for determining the reactive margin from voltage collapse in reactive power planning

    Publication Year: 1996 , Page(s): 1473 - 1481
    Cited by:  Papers (21)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (736 KB)  

    Power system reactive power planning requires the computation of the reactive power margin from the point of voltage collapse in the steady-state in order to quantify the adequacy of the level of installed reactive power plant. This reactive margin is the difference between the maximum reactive load distributed across selected power system nodes and the reactive load at the planned system operating point. The margin can be estimated by applying an optimisation method using the total reactive load as the objective, with the load flow equations as equality constraints, whilst including system limits such as generator reactive capability limits as inequality constraints. This paper describes a full AC formulation of the optimisation problem. It is solved using an interior point implementation of the Newton method developed for the optimal power flow. This avoids potential difficulties in identifying the binding inequality constraints View full abstract»

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  • Economically adapted transmission systems in open access schemes-application of genetic algorithms

    Publication Year: 1996 , Page(s): 1427 - 1440
    Cited by:  Papers (38)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1552 KB)  

    A dynamic transmission planning methodology using a genetic algorithm is formulated for the purpose of determining an economically adapted electric transmission system in a deregulated open access environment. Transmission investment sensitivity information linked to short term marginal income is used. A computer program is developed and applied to obtain a long range adapted transmission grid for the Chilean electrical system. Two open access pricing methodologies are evaluated in a spot price framework, as applied to the adapted grid over the time horizon View full abstract»

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  • Design and operation of a virtual reality operator-training system

    Publication Year: 1996 , Page(s): 1585 - 1591
    Cited by:  Papers (18)  |  Patents (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (916 KB)  

    The risks to equipment and personnel associated with the manual operation of switching station equipment demand rigorous personnel instruction. Additionally, switching errors reduce customer service quality. With the virtual reality operator-training simulator ESOPE-VR, trainees can practice all necessary switching operations in complete safety, while maintaining a high degree of realism. A speech-recognition system allows for complete control of the training session by the operator trainee, while sound immersion adds a dimension of realism to the virtual world. An expert-system validates the trainee's operations at all stages of the process and provides verbal context-sensitive advice whenever errors are made. A steady-state power-flow simulator recalculates network variables whenever operator actions lead to changes in topology. The automated conversion of station single-line diagrams to realistic three-dimensional models permits an operator to be trained economically for of a large number of stations View full abstract»

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  • Comparison of performance indices for detection of proximity to voltage collapse

    Publication Year: 1996 , Page(s): 1441 - 1450
    Cited by:  Papers (81)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (972 KB)  

    The paper proposes a new test function to be used in an existent performance index for detection of proximity to a static voltage collapse point. This test function is based on a reduction of the load flow Jacobian with respect to the critical bus of a system. The test function is compared with known singular values and eigenvalues indices, and with other previously proposed test functions. A thorough analysis of the similarities, advantages, and disadvantages of all these indices and test functions is presented. The techniques are tested and compared on the IEEE 300 bus test system, showing the effect of system characteristics and limits in these indices and functions View full abstract»

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  • Allocation of transmission fixed charges: an overview

    Publication Year: 1996 , Page(s): 1409 - 1418
    Cited by:  Papers (79)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (916 KB)  

    The application of marginal cost in pricing the transmission services has shown not effective mainly due to revenue reconciliation problems. To overcome this, a set of other methods derived from the MW-mile rule has been suggested to allocate transmission fixed costs. This paper compares such methods known as embedded cost methods in a centralized transmission network environment. Although these methods actually share the total cost and are very simple, they are usually rejected due to the lack of a good economic reasoning. The economic issue and the impact on the system expansion planning of such allocation are addressed in this paper. Some examples with the Brazilian transmission system illustrate the results derived from this analysis View full abstract»

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  • An analytical method for comparing natural diversity to DSM controlled diversity

    Publication Year: 1996 , Page(s): 1201 - 1208
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (704 KB)  

    The purpose of this paper is to report an analytical method of comparing natural diversity with controlled diversity, and to show the results of comparing the peak load resulting from natural diversity in a set of air conditioning units to the peak load that can be achieved with DSM control of the same set of air conditioners. In this study it is assumed that the energy use by the air conditioners is the same in both cases. Under this assumption, an analytical model for finding the probabilities of all the possible peak loads is developed and illustrated in case studies View full abstract»

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  • A methodology for probabilistic simultaneous transfer capability analysis

    Publication Year: 1996 , Page(s): 1269 - 1278
    Cited by:  Papers (55)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (924 KB)  

    This paper presents a methodology for simultaneous transfer capability analysis based on a probabilistic approach. All areas in a large scale power system are divided into three groups: (a) study area, (b) transfer participating areas, and (c) external areas which have no direct transactions or they have fixed transactions with the study area. A performance index based contingency selection procedure is applied within the study and transfer participating areas to rank those contingencies which will affect simultaneous transfer capability. The contingency ranking order is utilized by a variation of the Wind Chime diagram to selected contingencies which are then evaluated by an optimal power flow algorithm. Subsequently, the probability distribution of simultaneous transfer capability is computed based on the electric load, circuit and unit outage Markov models. The 24×3 bus IEEE RTS is utilized to evaluate the proposed method. The performance of the proposed method is also demonstrated on an actual large scale system (2182 bus, 8 area system) View full abstract»

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  • Data debugging for real-time power system monitoring based on pattern analysis

    Publication Year: 1996 , Page(s): 1592 - 1599
    Cited by:  Papers (14)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (788 KB)  

    This paper presents a new method for solving bad data acquisition problems in power system state estimation. The normalized innovations, available in the pre-filtering stage of a forecasting-aided state estimator, are used as input variables to a constructive artificial neural network (ANN). The ANN performs a pattern analysis in order to identify both topological and analogical errors. The performance of the method is evaluated and discussed for different types of error and operating conditions using the IEEE-24 bus system View full abstract»

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  • Revenue reconciled optimum pricing of transmission services

    Publication Year: 1996 , Page(s): 1419 - 1426
    Cited by:  Papers (13)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (728 KB)  

    This paper describes a methodology for evaluating an optimal set of transmission prices, to be charged for use of a transmission system on a time-of-use basis. The transmission prices are determined by maximising the global benefit of using the transmission system that allocates both capacity and operational costs. The security considerations are explicitly taken into account by incorporating security factors in the algorithm. The important issue of revenue recovery by the transmission utility is addressed by modifying the optimum prices without affecting the consumer behaviour. This can be achieved by setting the prices within indifference intervals over which consumers are insensitive to transmission prices. Application of the methodology is illustrated on the IEEE 24 bus test system View full abstract»

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  • Improved methodologies for the calculation of critical eigenvalues in small signal stability analysis

    Publication Year: 1996 , Page(s): 1209 - 1217
    Cited by:  Papers (32)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1012 KB)  

    This paper presents improved and new methodologies for the calculation of critical eigenvalues in the small-signal stability analysis of large electric power systems. They augment the robustness and efficiency of existing methods and provide new alternatives. The procedures are implementations of Newton's method, inverse power and Rayleigh quotient iterations, equipped with implicit deflation, and restarted Arnoldi with a locking mechanism and either shift-invert or semi-complex Cayley preconditioning. The various algorithms are compared and evaluated regarding convergence, performance and applicability View full abstract»

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  • Evaluating a restoration tool using Consolidated Edison's training simulator

    Publication Year: 1996 , Page(s): 1636 - 1642
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (768 KB)  

    To facilitate the implementation of restoration procedures in the event of a blackout, Consolidated Edison is considering the implementation of a knowledge-based restoration tool. This tool would not only guide operators through the execution of predefined procedures, but would also have the ability to adapt and modify these procedures if needed. These requirements can be met if the tool is built on top of a model of the power system and if it decomposes the procedure into components with an explicit or easily identifiable purpose. This tool has been developed and integrated with ConEd's operator training simulator so that it can be used to train the operators in the restoration procedures. After evaluation it may be enhanced to become an on-line tool for use during an actual restoration View full abstract»

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  • Critical cases in the optimal power flow

    Publication Year: 1996 , Page(s): 1509 - 1518
    Cited by:  Papers (13)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (908 KB)  

    This paper presents a systematic analysis of the main reasons for the failure of solution algorithms in the general power system nonlinear optimal power flow (OPF) problem. It defines the concept of critical and noncritical OPF problems and identifies and categorizes the main types of such cases. In essence, a noncritical case is one where a small variation in a parameter leads to a small change in the optimum solution. Alternatively, critical cases are such that a small variation in a problem parameter leads to either the loss of local optimality or feasibility. Both of these can result in a sharp discontinuity in the solution. Numerical and theoretical examples illustrate each of these cases View full abstract»

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  • Remote cranking of steam electric stations

    Publication Year: 1996 , Page(s): 1613 - 1618
    Cited by:  Papers (11)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (536 KB)  

    This paper focuses industry attention on power system restoration. During the initial phase of restoration, black-start combustion turbines are often considered as remote cranking sources for the start-up of steam electric stations. In general, remote cranking operation is carefully planned, simulated and then verified by field tests. This paper describes the planning and simulation used in black-start of two coal-fired generating units utilizing remote combustion turbines. It discusses a number of constraints which have to be considered and simulated in preparation for testing and verification. The paper concludes that, in order to minimize the possibility of damage to equipment during testing or actual restoration, it is necessary to undertake extensive simulation of the procedure. It recommends that the realistic generator reactive capability models be made a part of the network models to allow: optimum selections of tap positions for all the transformers within the remote cranking power system, thus providing adequate lead/lag reactive powers and to maintain acceptable voltage profile while proceeding through various stages of operation View full abstract»

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  • Development of transient stability control system (TSC system) based on on-line stability calculation

    Publication Year: 1996 , Page(s): 1463 - 1472
    Cited by:  Papers (35)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (896 KB)  

    This paper describes a new transient stability control system named the TSC system developed for application to the trunk power system of Chubu Electric Power Co. (CEPCO). The TSC system prevents wide-area power system blackout by shedding optimal generators when a serious fault occurs. This system has the following features: (1) the TSC system performs detailed stability calculations based on online information telemetered from the actual network, and it periodically evaluates the stability of the power system against contingencies with a high degree of accuracy. The system selects the optimum generators to be shed; (2) if a contingency actually occurs, the generators to be shed that were determined in advance are shed about 150 ms after fault occurrence to maintain the stability of the power system; and (3) the system can be applied to any power system configuration of CEPCO, such as a loop network, radial network, etc. The TSC system will be put into regular service in June 1995. It will be the world's first real-time stability control system that performs detailed transient stability calculations on a large power system online View full abstract»

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  • An improved voltage control on large-scale power system

    Publication Year: 1996 , Page(s): 1295 - 1303
    Cited by:  Papers (66)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (796 KB)  

    To achieve a better voltage-VAr control in the electric power transmission system, different facilities are used. Generators are equipped with automatic voltage regulators to cope with sudden and random voltage changes caused by natural load fluctuations or failures. Other devices like capacitors, inductors, transformers with on load tap changers are installed on the network. Faced with the evolution of the network and operating conditions, electricity utilities are more and more interested in overall and coherent control systems, automatic or not. These systems are expected to co-ordinate the actions of local facilities for a better voltage control (more stable and faster reaction) inside different areas of the network in case of greater voltage and VAr variations. They afford a better use of existing reactive resources. Also, installation of new devices can be avoided allowing economy of investment. With this in mind, EDF has designed a system called Co-ordinated Secondary Voltage Control (CSVC). It is an automatic closed loop system with a dynamic of a few minutes. It takes into account the network conditions (topology, loads), the voltage limits and the generator operating constraints. This paper presents improvements which allow the CSVC to control the voltage profile and different kinds of reactive means on a large-scale power system, Furthermore, this paper presents a solution to spread out investment costs over several years, considering a deployment gradually extended View full abstract»

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  • Distribution network reconfiguration: single loop optimization

    Publication Year: 1996 , Page(s): 1643 - 1647
    Cited by:  Papers (43)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (416 KB)  

    Successful applications of the single-loop optimization approach have been reported for resolving the distribution network reconfiguration problem. This approach was originally proposed as an intuitive heuristic method and has been understood so as well. This paper attempts to provide an analytical description and a systematic understanding about the approach via qualitative analysis. It formulates the problem as a nonlinear integer optimization problem which, if linearized, could be approximately represented by an integer LP (linear programming) problem. This understanding leads to the consideration of applying the concept of the simplex method normally used for solving LP problems, which, in turn, leads to the direct derivation of the single-loop optimization approach. This fact indicates that the single-loop optimization approach actually originates from the same technical principle as the simplex method. This paper also presents a simple and effective scheme to efficiently determine the switch exchanges within a loop for minimum line losses, and proposes a heuristic scheme to develop the optimal switch plan with minimum switch operations in order to accomplish the transition from the initial configuration to the optimal configuration. An example network is studied using the proposed approaches and satisfactory results are obtained View full abstract»

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  • Neural-networks for predicting the operation of an under-frequency load shedding system

    Publication Year: 1996 , Page(s): 1350 - 1358
    Cited by:  Papers (13)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1532 KB)  

    Dynamic security assessment is of special importance to island power systems. The CPU time required in order to apply conventional methods for those calculations does not allow real-time application. The fast calculation time is, therefore, an important advantage of artificial neural networks compared to other methods. This paper presents two neural network models that were designed to calculate the minimal frequency and the load shedding system operation during a forced outage of a generating unit. The minimal frequency and the extent of the load shedding are strong indications of the severity of the fault. Hence, it is a significant part of the dynamic security assessment procedure View full abstract»

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  • Stochastic modeling of street lamps operation

    Publication Year: 1996 , Page(s): 1482 - 1488
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (504 KB)  

    This paper is based on the application of stochastic differential equations in simulating the active power consumption in street lamp operation, both in transient and steady state. The method worked as follows. Firstly, a collection of about 400 street lamps was measured in the laboratory. In addition, a theoretical model for the mean power consumption was derived. This model was expressed by means of a linear stochastic differential equations dependent on two parameter processes. The aforementioned parameters were then estimated from the experimental data and the equations solved numerically leading to a representation of the mean active power by means of a stochastic process View full abstract»

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  • A new logic-based alarm analyzer for on-line operational environment

    Publication Year: 1996 , Page(s): 1600 - 1606
    Cited by:  Papers (9)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (712 KB)  

    Existing fault diagnostic techniques for power systems are based on the operation of breakers using on-line alarm messages available from the energy management systems (EMSs). Some utility systems also acquire, on-line, the information on relay operations in order to increase the precision of fault diagnosis. This paper proposes a new on-line fault diagnosis system called Intelligent Alarm Analyzer (IAA). This paper identifies the information from sequence-of-events recorders (SERs) at the substations that can be used in the EMS environment. The breaker operations together with the selected SER information provide sufficient data to help pinpoint the fault location(s) and malfunctioning device(s) online. The proposed IAA is capable of handling transmission line, busbar and transformer faults as well as relay and breaker malfunctions. The other unique feature of IAA is its logic-based algorithms implemented in an object-oriented software structure. Based on our testing with the actual data from ENEL, the Italian power system, the proposed implementation is highly efficient and promising for the on-line environment View full abstract»

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  • Enhancing power engineering education through the use of design modules

    Publication Year: 1996 , Page(s): 1131 - 1138
    Cited by:  Papers (6)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (788 KB)  

    This paper describes the main features of four design modules that form part of the curriculum for the final year power engineering students at the Nanyang Technological University, Singapore. Through the use of these modules, the students gain an insight into the various aspects of power engineering-including power electronics and drives-and this will hopefully help them in a better understanding of the practical aspects of power engineering, and therefore make them better engineers in the power industry. The four modules described are Generating Capacity Expansion Planning, Rectifier and DC Motor Control, Power Systems Operations Planning, and Security Enhancement using Optimal Power Flow View full abstract»

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  • Fast three phase load flow methods

    Publication Year: 1996 , Page(s): 1547 - 1554
    Cited by:  Papers (34)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (680 KB)  

    In this paper, three-phase sequence decoupling-compensation models of unsymmetrical transmission lines are introduced. By combining these models with the well-known Newton-Raphson and fast-decoupled algorithms, two novel methods-sequence decoupling-compensation Newton-Raphson (SDCNR) and sequence decoupling-compensation fast-decoupled (SDCFD) methods-used for three-phase load flow studies are proposed, which can be used to analyze both normal and abnormal three-phase power system steady-state operation. The computation accuracy, computation speed and convergence characteristics of these methods are then investigated. From these investigations, their advantages of high accuracy, high speed, reliable convergence are verified. In this paper, parallel implementation of these methods is also discussed View full abstract»

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  • System restoration guidelines: how to set-up, conduct, and evaluate a drill

    Publication Year: 1996 , Page(s): 1619 - 1629
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (900 KB)  

    Once an organization has developed a restoration plan it needs a method to evaluate that plan. The evaluation method described here is the use of a system restoration drill/exercise. Simulating restoration conditions will provide a measure of an organization's ability to respond to a real incident. Periodic drills and exercises help to maintain a high state of preparedness for those individuals involved. These drills also test and validate the organization's restoration plan before it is activated during an actual incident. This paper describes a set of guides for: how to set up a restoration drill; how to conduct a drill; and then how to evaluate a restoration drill View full abstract»

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  • An improved block-parallel Newton method via epsilon decompositions for load-flow calculations

    Publication Year: 1996 , Page(s): 1519 - 1527
    Cited by:  Papers (9)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (852 KB)  

    The objective of this paper is to present a new method for parallel load-flow calculations based on an effective decomposition of the network. In the solution process, the authors utilize the block-parallel Newton method which involves only diagonal blocks of the Jacobian. The underlying structure is obtained by applying the epsilon decomposition algorithm which eliminates weak coupling elements from the matrix. They demonstrate that the iterative process can be significantly accelerated by making certain modifications in mismatch evaluation for buses connecting different blocks. Experiments on the hypercube confirm that the proposed method is indeed effective, particularly for problems where a good initial approximation is available (such as outage assessment) View full abstract»

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  • Experience with application of reliability and value of service analysis in system planning

    Publication Year: 1996 , Page(s): 1489 - 1496
    Cited by:  Papers (17)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (800 KB)  

    This paper documents the material presented at the IEEE 1994 Summer Power Meeting Panel on the application of reliability in least cost power system planning, sponsored by the Application of Probability Methods (APM) Subcommittee of the Power System Engineering Committee of IEEE. The paper contains short notes by five panelists, representing five electric utilities in North America, on the application of reliability and value of service analysis in power system planning View full abstract»

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  • On-line detection of power system small disturbance voltage instability

    Publication Year: 1996 , Page(s): 1304 - 1313
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (820 KB)  

    Small disturbance (SD) voltage stability (or instability) deals with a system's ability to maintain satisfactory voltages following a small disturbance. For an operating condition, a system's SD voltage stability depends on the proximity of the condition to the critical point (or voltage collapse point). A Q angle and Q directional derivatives are proposed for SD voltage instability detection and weak bus identification, respectively. The Q angle index can handle different kinds of loads, e.g., constant P and Q, constant impedance, and constant current, or a combination of them, and is effective in dealing with generator VAr limits. Moreover, the computation speed of the Q angle is fast, which makes it suitable for on-line application. Simulation results using two power systems are provided View full abstract»

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Aims & Scope

Covers the requirements, planning, analysis, reliability, operation, and economics of electric generating, transmission, and distribution systems for general industrial, commercial, public, and domestic consumption.

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Meet Our Editors

Editor-in-Chief
Antonio J. Conejo
The Ohio State University