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Power Systems, IEEE Transactions on

Issue 1 • Date Feb 2001

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Displaying Results 1 - 21 of 21
  • Application of mechanism design to electric power markets

    Page(s): 1 - 8
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (124 KB) |  | HTML iconHTML  

    As competition is introduced across the electric power industry around the world, market design for the industry is urgently needed to shape its future structure and performance. When generator companies compete with one another in a deregulated market, they may not be willing to share the information needed to perform an economic dispatch of the generation. Using game theory, this paper designs a new mechanism that achieves efficiency (economic dispatch) in spite of this information problem. In this mechanism, when each company acts in the best of its own interests, the outcome is efficient. The paper demonstrates the merits of the mechanism by simulations including the IEEE 14-bus case. View full abstract»

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  • A future application environment for BC Hydro's EMS

    Page(s): 9 - 14
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (72 KB)  

    The paper reports on the results of a tailored collaboration project sponsored by BC Hydro and EPRI to review the state-of-the-art in EMS architectures addressing the necessary attributes of a modern EMS with respect to scalability, database and user interface openness, flexibility and conformance to industry standards, as well as to provide a migration path for the existing BC Hydro's EMS. This review was intended to assist BC Hydro in identifying functionality and standard requirements of future EMS procurements and a migration path for a future BC Hydro application program environment. The proposed migration path was prototyped to verify its prudence and applicability in providing an open architecture environment for EMS applications. The BC Hydro On-Line Voltage Stability Analysis (OLVSA) application developed by BC Hydro and Powertech Labs was chosen and integrated into the prototype View full abstract»

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  • Long-term thermal power planning at VEW ENERGIE using a multi-interval Bloom and Gallant method

    Page(s): 69 - 77
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (212 KB)  

    Bloom and Gallant have proposed an elegant model for finding the optimal thermal schedule subject to matching the load duration curve and general linear constraints. Their method is based on a linear program with some linear equality constraints and many linear inequality constraints. There are well-documented specialized linear programming algorithms that are able to solve this problem. This paper proposes the extension of the Bloom and Gallant model to several successive intervals with constraints on generation encompassing different intervals. A procedure for finding an initial feasible point, which is an essential part of the solution procedure, is described here, together with details of the modeling of several operational constraints and computational results with real test cases View full abstract»

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  • Voltage security enhancement via coordinated control

    Page(s): 127 - 135
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (196 KB) |  | HTML iconHTML  

    The problem of analytically coordinating dissimilar voltage control actions to prevent voltage collapse in a large power system is addressed. A framework for hybrid voltage control based on coordination of controls with different response time and dynamic characteristics is presented. The proposed method is based on a security constrained steady-state approach. The minimum distance from the operating point to the bifurcation boundary is used to evaluate system voltage security. The optimal control direction toward adequate security is then obtained by calculating the sensitivity of the minimum distance with respect to control parameters. The actual dispatch of controls along the optimal direction, which takes into account impacts of economic cost and control availability, is determined as the solution of a multiple-stage optimization problem using differential dynamic programming. The algorithm is demonstrated for a system with dynamic load models representing the main grid of New South Wales, Australia View full abstract»

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  • Z-bus loss allocation

    Page(s): 105 - 110
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (144 KB) |  | HTML iconHTML  

    This paper presents a new procedure for allocating transmission losses to generators and loads in the context of pools operated under a single marginal price derived from a merit-order approach. The procedure is based on the network Z-bus matrix, although all required computations exploit the sparse Y-bus matrix. One innovative feature and advantage of this method is that, unlike other proposed approaches, it exploits the full set of network equations and does not require any simplifying assumptions. The method is based on a solved load flow and is easily understood and implemented. The loss allocation process emphasizes current rather than power injections, an approach that is intuitively reasonable and leads to a natural separation of system losses among the network buses. Results illustrate the consistency of the new allocation process with expected results and with the performance of other methods View full abstract»

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  • A DEA study to evaluate the relative efficiency and investigate the district reorganization of the Taiwan Power Company

    Page(s): 170 - 178
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (260 KB) |  | HTML iconHTML  

    In this study, data envelopment analysis (DEA) models were applied to evaluate the relative efficiencies of twenty-two electricity distribution districts of the Taiwan Power Company (TPC) in Taiwan, ROC. The empirical study showed that the TPC districts have good overall efficiency. We found that eleven districts were inefficient. Most of the inefficient districts suffer from scale inefficiency to a greater degree than technical inefficiency. We suggested the specific improvement directions for the corresponding inefficient districts. This study also investigated district reorganization to increase the efficiency. The proposed district reorganization alternatives have higher efficiency scores than the current one View full abstract»

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  • Transmission network expansion planning under a Tabu Search approach

    Page(s): 62 - 68
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (100 KB) |  | HTML iconHTML  

    This paper describes an implementation of Tabu Search to cope with long-term transmission network expansion planning problems. Tabu Search is a metaheuristic proposed in 1989 to be applied to combinatorial problems. To assess the potential of our approach we test it with two cases of transmission network expansion planning. The results obtained by our approach let us to conclude that TS is a robust and promising technique to be applied in this problem View full abstract»

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  • Comparison of reduced-order dynamic models of induction machines

    Page(s): 119 - 126
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (164 KB) |  | HTML iconHTML  

    The paper deals with the validity of various dynamic models of induction machines. The fifth-order Park model and various reduced-order models are used to predict the low-frequency dynamic response of a 15 kW induction machine, and the theoretical results are compared with an extensive series of measurements. Several transfer functions are investigated in the perturbation frequency region below 35 Hz using three types of basic excitations: perturbations in the shaft torque, supply voltage and supply frequency. The maximum perturbation frequency for an error less than 10% is used to study the validity range of the models; this range is evaluated for each model and transfer function, using the data of 31 different machines. The influence of the machine parameters and various physical phenomena is studied. The results show that a large number of transfer functions is needed for judging the general validity of a dynamic model View full abstract»

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  • Enforcing passivity for admittance matrices approximated by rational functions

    Page(s): 97 - 104
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (172 KB) |  | HTML iconHTML  

    A linear power system component can be included in a transient simulation as a terminal equivalent by approximating its admittance matrix Y by rational functions in the frequency domain. Physical behavior of the resulting model entails that it should absorb active power for any set of applied voltages, at any frequency. This requires the real part of Y to be positive definite (PD). We calculate a correction to the rational approximation of Y which enforces the PD-criterion to be satisfied. The correction is minimal with respect to the fitting error. The method is based on linearization and constrained minimization by quadratic programming. Examples show that models not satisfying the PD-criterion can lead to an unstable simulation, even though the rational approximation has stable poles only. Enforcement of the PD-criterion is demonstrated to give a stable result View full abstract»

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  • Simulation of the start-up of a Hydro Power plant for the emergency power supply of a nuclear power station

    Page(s): 163 - 169
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (100 KB) |  | HTML iconHTML  

    A hydro power plant and a nuclear power plant's auxiliaries are modeled using the Electromagnetic Transients Program (EMTP). The computer models allow for the simulation of a hydro generator start-up and the following energization of a nuclear power station's auxiliary motors under off-nominal voltage and frequency conditions. The paper describes the derivation of generator, turbine, exciter, and induction motor models, and their individual validation through field measurements. The complete power system model is verified by comparing simulation results to measurements, as obtained during an Engineered Safeguards Functions (ESF) test of the emergency power system of Oconee nuclear power plant View full abstract»

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  • Auction design in day-ahead electricity markets

    Page(s): 88 - 96
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (148 KB)  

    Competition in day-ahead electricity markets has been established through auctions where generators and loads bid prices and quantities. Different approaches have been discussed regarding the market auction design. Multi-round auctions, despite its implementation complexity, allow market participants to adapt their successive bids to market prices considering their operational and economic constraints. However, most of the day-ahead electricity market implementations use noniterative single-round auctions. This paper presents a market simulator to compare both auction models. Different auction alternatives, such as the Spanish single-round auction that takes into account special conditions included in the generator bids, and multi-round auctions with different stopping rules, are analyzed. The results and acquired experience in the simulation of the Spanish market, started in January 1998, are presented. Hourly market prices, average daily price, price/demand correlation and several economic efficiency indicators, such as generator surplus, consumer surplus and social welfare, are compared to derive conclusions regarding the performance of the auction alternatives View full abstract»

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  • A combined framework for service identification and congestion management

    Page(s): 56 - 61
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (132 KB) |  | HTML iconHTML  

    Service identification and congestion management are important functions of the ISO in maintaining system security and reliability. Most approaches in the literature solve the problem sequentially, which may lead to an under or over-estimation of the service requirement and transaction curtailment. A few of them do it iteratively which is quite time consuming. In this paper, a combined framework for service identification and congestion management is proposed. The ideal objective function is to maximize the overall profit of all market participants. Practically, an upper bound cost minimization is suggested and has been applied to identify two of the services, the reactive support and real power loss services, in case of congestion. The service costs plus the congestion cost are minimized. Results show that the proposed approach results in a smaller transaction curtailment. The curtailment also depends on the relative cost of congestion with respect to the cost of services View full abstract»

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  • Neural networks for short-term load forecasting: a review and evaluation

    Page(s): 44 - 55
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (172 KB) |  | HTML iconHTML  

    Load forecasting has become one of the major areas of research in electrical engineering, and most traditional forecasting models and artificial intelligence techniques have been tried out in this task. Artificial neural networks (NNs) have lately received much attention, and a great number of papers have reported successful experiments and practical tests with them. Nevertheless, some authors remain skeptical, and believe that the advantages of using NNs in forecasting have not been systematically proved yet. In order to investigate the reasons for such skepticism, this review examines a collection of papers (published between 1991 and 1999) that report the application of NNs to short-term load forecasting. Our aim is to help to clarify the issue, by critically evaluating the ways in which the NNs proposed in these papers were designed and tested View full abstract»

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  • Recent applications of linear analysis techniques

    Page(s): 154 - 162
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (188 KB) |  | HTML iconHTML  

    This paper is based on material presented at the Panel Session: Recent Applications of Linear Analysis Techniques conducted during the 1998 IEEE PES Summer Meeting. The topics discussed include: control system design; system identification; large scale system applications; simultaneous coordination of power system stabilisers and FACTS controllers; robust power system stabilisation; small signal stability analysis based on time-domain identified models; EM transient studies modal analysis; and power system dynamics nonlinearities, normal forms method View full abstract»

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  • Dynamic economic dispatch: feasible and optimal solutions

    Page(s): 22 - 28
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (152 KB) |  | HTML iconHTML  

    Dynamic economic dispatch is an extension of the conventional economic dispatch problem that takes into consideration the limits on the ramp rate of the generating units. This paper examines the factors that affect the feasibility and optimality of solutions to this problem. It proposes two new solution methods. The first is guaranteed to find a feasible solution even when the load profile is nonmonotonic. The second is an efficient technique for funding the optimal solution. The results obtained with these methods are compared with those obtained using previously published methods View full abstract»

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  • Dynamic security constrained optimal power flow/VAr planning

    Page(s): 38 - 43
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (100 KB) |  | HTML iconHTML  

    Traditionally security constrained optimal power flow and VAr planning methods consider static security observing voltage profile and flow constraints under normal and post contingency conditions. Ideally, these formulations should be extended to consider dynamic security. This paper reports on a BC Hydro/CEPEL joint effort establishing a dynamic security constrained OPF/VAr planning tool which considers simultaneously static constraints as well as voltage stability constraints. This paper covers the details of formulation and implementation of the tool together with the test results on a large scale North American utility system and a reduced Brazilian system View full abstract»

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  • Wide-area measurement based stabilizing control of large power systems-a decentralized/hierarchical approach

    Page(s): 136 - 153
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (508 KB)  

    The aim of this paper is to assess the capability of the emerging synchronized phasor measurement technology in improving the overall stability of the Hydro-Quebec transmission system through supplementary modulation of voltage regulators. Following a thorough singular value and eigenvalue analysis of the system dynamic interactions, five control sites consisting of four generators and one synchronous condenser are chosen to implement new power system stabilizers with a supplementary input from remote phasor measuring units, geographically spread over nine electrically coherent areas. Since the remote feedback loops are built on top of an existing decentralized control system, this design approach results in a decentralized/hierarchical control architecture with significant advantages in terms of reliability and operational flexibility. A systematic control and measurement pairing yielded four dominant natural loops, each associated with a significant open-loop inter-area oscillatory mode at 0.06, 0.4, 0.7 and 0.95 Hz respectively. These PSSs have a speed sensitive local loop operating in the usual way, and a wide-area measurement based global loop which involves a single differential frequency signal between two suitably selected areas. The tuning and coordination technique for these advanced multiple input signals PSSs is described. Their impacts on the system is assessed using both small-signal analysis and nonlinear simulations in a transient stability program. Wide-area stabilizing controllers have a significant potential in improving the dynamic performance of the Hydro-Quebec's existing power system View full abstract»

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  • Optimal bidding strategies and modeling of imperfect information among competitive generators

    Page(s): 15 - 21
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (148 KB) |  | HTML iconHTML  

    The emerging electricity market behaves more like an oligopoly than a perfectly competitive market due to special features such as, a limited number of producers, large investment size (barrier to entry), transmission constraints, and transmission losses which discourage purchase from distant suppliers. This makes it practicable for only a few independent power suppliers to service a given geographic region and in this imperfect market each power supplier can increase its own profit through strategic bidding. The profit of each supplier is influenced to varying extents by differences in the degree of imperfection of knowledge of rival suppliers. A new framework to build bidding strategies for power suppliers in an electricity market is presented in this paper. It is assumed that each supplier bids a linear supply function, and that the system is dispatched to minimize customer payments. Each supplier chooses the coefficients in the linear supply function to maximize benefits, subject to expectations about how rival suppliers will bid. A stochastic optimization formulation is developed and two methods proposed for describing and solving this problem. A numerical example serves to illustrate the essential features of the approach and the results are used to investigate the potential market power View full abstract»

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  • Reliability and costs optimization for distribution networks expansion using an evolutionary algorithm

    Page(s): 111 - 118
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (156 KB) |  | HTML iconHTML  

    This paper presents a multiobjective optimization methodology, using an evolutionary algorithm, for finding out the best distribution network reliability while simultaneously minimizing the system expansion costs. A nonlinear mixed integer optimization model, achieving the optimal sizing and location of future feeders (reserve feeders and operation feeders) and substations, has been used. The proposed methodology has been tested intensively for distribution systems with dimensions that are significantly larger than the ones frequently found in the papers about this issue. Furthermore, this methodology is general since it is suitable for the multiobjective optimization of n objectives simultaneously. The algorithm can determine the set of optimal nondominated solutions, allowing the planner to obtain the optimal locations and sizes of the reserve feeders that achieve the best system reliability with the lowest expansion costs. The model and the algorithm have been applied intensively to real life power systems showing its potential of applicability to large distribution networks in practice View full abstract»

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  • Security modeling for power system reliability evaluation

    Page(s): 29 - 37
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (252 KB) |  | HTML iconHTML  

    This paper presents conceptual development, computation procedure and simulation results of the methodology for modeling security within reliability evaluation of power systems. The proposed approach takes into account activation of protection and automatic controls, local actions of operators, as well as centralized decisions taken by system operators. Transient stability, frequency variation during governor control, emergency and normal levels of line thermal protection, automatic generation control, overload rotation and economic dispatch are the main points of the developed procedure. It can be directly incorporated into the hybrid model for reliability evaluation of different operating states View full abstract»

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  • Reliability and reserve in competitive electricity market scheduling

    Page(s): 78 - 87
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (244 KB)  

    Power systems are typically scheduled at least cost subject to operational and security constraints. Generally, no account is taken of generator reliability when scheduling units. Also, the security criteria, which include reserve, are usually deterministic in nature. This paper proposes a method to consider generator reliability explicitly in the scheduling problem. A competitive structure is proposed which includes a market for reserve. This is formulated as an augmented Lagrangian dual function and is solved using a new recurrent neural network. The price for reserve is used, along with the unit reliability, to find a balance between the cost of reserve and the risk of not providing it 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