Scheduled System Maintenance:
Some services will be unavailable Sunday, March 29th through Monday, March 30th. We apologize for the inconvenience.
By Topic

Power Systems, IEEE Transactions on

Issue 4 • Date Nov. 2005

Filter Results

Displaying Results 1 - 25 of 65
  • Table of contents

    Publication Year: 2005 , Page(s): c1 - 1666
    Save to Project icon | Request Permissions | PDF file iconPDF (51 KB)  
    Freely Available from IEEE
  • IEEE Transactions on Power Systems publication information

    Publication Year: 2005 , Page(s): c2
    Save to Project icon | Request Permissions | PDF file iconPDF (37 KB)  
    Freely Available from IEEE
  • A comparison of the optimal multiplier in polar and rectangular coordinates

    Publication Year: 2005 , Page(s): 1667 - 1674
    Cited by:  Papers (26)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (360 KB) |  | HTML iconHTML  

    Studies of the optimal multiplier (or optimal step size) modification to the standard Newton-Raphson (NR) load flow have mainly focused on highly stressed and unsolvable systems. This paper extends these previous studies by comparing performance of the NR load flow with and without optimal multipliers for a variety of unstressed, stressed, and unsolvable systems. Also, the impact of coordinate system choice in representing the voltage phasor at each bus is considered. In total, four solution methods are compared: the NR algorithm with and without optimal multipliers using polar and rectangular coordinates. This comparison is carried out by combining analysis of the optimal multiplier technique with empirical results for two-bus, 118-bus, and 10 274-bus test cases. These results indicate that the polar NR load flow with optimal multipliers is the best method of solution for both solvable and unsolvable cases. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • An agent-based anomaly detection architecture for condition monitoring

    Publication Year: 2005 , Page(s): 1675 - 1682
    Cited by:  Papers (10)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (552 KB) |  | HTML iconHTML  

    Online diagnostics and online condition monitoring are important functions within the operation and maintenance of a power plant. When there is knowledge of the relationships between the raw data and the underlying phenomena within the plant item, typical intelligent system-based interpretation algorithms can be implemented. Increasingly, health data is captured without any underlying knowledge concerning the link between the data and their relationship to physical and electrical phenomena within the plant item. This leads to the requirement for dynamic and learning condition monitoring systems that are able to determine the expected and normal plant behavior over time. This paper describes how multi-agent system technology can be used as the underpinning platform for such condition monitoring systems. This is demonstrated through a prototype multi-agent anomaly detection system applied to a 2.5-MW diesel engine driven alternator system. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Power system state estimation via globally convergent methods

    Publication Year: 2005 , Page(s): 1683 - 1689
    Cited by:  Papers (12)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (272 KB) |  | HTML iconHTML  

    This paper introduces backtracking and trust region methods into power system state estimation. The traditional Newton (Gauss-Newton) method is not always reliable particularly in the presence of bad data, topological or parameter errors. The motivation was to enhance convergence properties of the state estimator under those conditions, and together with QR factorization to make a globally convergent and reliable algorithm. The trust region formulation shows that such a model is more robust than the traditional Newton (Gauss-Newton) or Backtracking (line search) algorithm. Both algorithms have been programmed and applied to representative power networks, and the computational requirement has been found. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Improved genetic algorithm for power economic dispatch of units with valve-point effects and multiple fuels

    Publication Year: 2005 , Page(s): 1690 - 1699
    Cited by:  Papers (119)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (560 KB) |  | HTML iconHTML  

    This paper presents an improved genetic algorithm with multiplier updating (IGA_MU) to solve power economic dispatch (PED) problems of units with valve-point effects and multiple fuels. The proposed IGA_MU integrates the improved genetic algorithm (IGA) and the multiplier updating (MU). The IGA equipped with an improved evolutionary direction operator and a migration operation can efficiently search and actively explore solutions, and the MU is employed to handle the equality and inequality constraints of the PED problem. Few PED problem-related studies have seldom addressed both valve-point loadings and change fuels. To show the advantages of the proposed algorithm, which was applied to test PED problems with one example considering valve-point effects, one example considering multiple fuels, and one example addressing both valve-point effects and multiple fuels. Additionally, the proposed algorithm was compared with previous methods and the conventional genetic algorithm (CGA) with the MU (CGA_MU), revealing that the proposed IGA_MU is more effective than previous approaches, and applies the realistic PED problem more efficiently than does the CGA_MU. Especially, the proposed algorithm is highly promising for the large-scale system of the actual PED operation. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Optimal metering systems for monitoring power networks under multiple topological scenarios

    Publication Year: 2005 , Page(s): 1700 - 1708
    Cited by:  Papers (16)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (264 KB) |  | HTML iconHTML  

    This work presents a methodology for designing optimal metering systems for real-time power system monitoring, taking into account different topologies that the network may experiment. Genetic algorithms are employed to achieve a trade-off between investment costs and reliability of the state estimation process under many different topology scenarios. This is done by formulating a fitness function where the cost of the metering system is minimized, while no critical measurements and/or critical sets are allowed in the optimal solution. An efficient algorithm for the identification of critical measurements and sets (irrespective of state estimation runs) is employed during the evaluation of the fitness function. Simulation results illustrate the performance of the proposed method. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • A parallel transient stability simulation for power systems

    Publication Year: 2005 , Page(s): 1709 - 1717
    Cited by:  Papers (28)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (400 KB) |  | HTML iconHTML  

    As power systems continue to develop, online dynamic security analysis and real-time simulation using parallel computing are becoming increasingly important. This paper presents a novel multilevel partition scheme for parallel computing based on power network regional characteristics and describes the design and implementation of a hierarchical block bordered diagonal form (BBDF) algorithm for power network computation. Some optimization schemes are further proposed to reduce the computation and communication time and to improve the scalability of the program. The simulation results show that, for a large network with 2115 nodes, 2614 branches, 248 generators, and 544 loads, the proposed algorithms and schemes run ten times faster on a cluster system with eight CPUs than on a single CPU. Thus, they satisfy the real-time simulation requirement for large-scale power grids. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • A distribution company energy acquisition market model with integration of distributed generation and load curtailment options

    Publication Year: 2005 , Page(s): 1718 - 1727
    Cited by:  Papers (46)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (632 KB) |  | HTML iconHTML  

    This work presents a novel day-ahead energy acquisition model for a distribution company (DisCo) in a competitive market based on Pool and financial bilateral contracts. The market structure encompasses wholesale generation companies, distributed generation (DG) units of independent producers, DG units owned by the DisCo, and load curtailment options. Thus, while satisfying its technical constraints, the DisCo purchases active and reactive power according to the offers of DG units, customers, and the wholesale market. The resulting optimal power flow model is implemented with an object-oriented approach, which is solved numerically by making use of a branch and border sequential quadratic programming algorithm. The model is validated in test systems and then applied to a real case study. Results show the general applicability of the proposed model, with potential cost savings for the DisCo. Finally, the analysis of Lagrange multipliers gives valuable information, which can be used to improve the market design and to extend the use of the model to a more general market structure such as a power exchange. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Transmission rights and transmission expansions

    Publication Year: 2005 , Page(s): 1728 - 1737
    Cited by:  Papers (26)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (248 KB)  

    In this paper, we propose a new method of defining rights that may be assigned to the developer of a transmission expansion project. They include a right to collect the value of the capacity provided by the expansion project as well as the value arising from the admittance of the expansion project. This approach not only ties the rights allocation to actual physical characteristics of the transmission project but also allows such allocation to remain independent both of the order in which the projects are treated and of any previously allocated transmission rights. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Electrothermal coordination part II: case studies

    Publication Year: 2005 , Page(s): 1738 - 1745
    Cited by:  Papers (14)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (400 KB) |  | HTML iconHTML  

    The concept of electrothermal coordination (ETC) in power system operation introduced in Part I proposes to exploit thermal inertia to coordinate line temperature dynamics with existing power system controls, thus increasing power transfer capability and enhancing system security and economic performance. In this Part II, the characteristics of ETC and its benefits in operational functions such as augmenting power transfer capability, emergency control, congestion management, and system loadability are numerically analyzed through a number of case studies. This paper also examines some practical issues concerning the deployment of ETC. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • The conditions for obtaining feasible solutions to security-constrained unit commitment problems

    Publication Year: 2005 , Page(s): 1746 - 1756
    Cited by:  Papers (31)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (512 KB) |  | HTML iconHTML  

    The core of solving security-constrained unit commitment (SCUC) problems within the Lagrangian relaxation framework is how to obtain feasible solutions. However, due to the existence of the transmission constraints, it is very difficult to determine if feasible solutions to SCUC problems can be obtained by adjusting generation levels with the commitment states obtained in the dual solution of Lagrangian relaxation. The analytical and computational necessary and sufficient conditions are presented in this paper to determine the feasible unit commitment states with grid security constraints. The analytical conditions are proved rigorously based on the feasibility theorem of the Benders decomposition. These conditions are very crucial for developing an efficient method for obtaining feasible solutions to SCUC problems. Numerical testing results show that these conditions are effective. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Fault analysis on distribution feeders with distributed generators

    Publication Year: 2005 , Page(s): 1757 - 1764
    Cited by:  Papers (45)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (496 KB) |  | HTML iconHTML  

    This paper shows that the current an inverter interfaced distributed generator (IIDG) contributes to a fault varies considerably, due mainly to fast response of its controller. This paper proposes a method to extend the conventional fault analysis methods so that IIDG contribution can be estimated in the fault analysis. The proposed method gives rms profiles of the fault currents of interest (IIDG contribution and the fault currents the protective device will see). Test results, based on a prototype feeder, show that the proposed approach can estimate the fault current's contributions under both balanced and unbalanced fault conditions. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Determining generator contributions to transmission system using parallel vector evaluated particle swarm optimization

    Publication Year: 2005 , Page(s): 1765 - 1774
    Cited by:  Papers (23)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (672 KB) |  | HTML iconHTML  

    In this paper, the generator contributions to the transmission system are determined by an evolutionary computation technique. Evaluating the contributions of generators to the power flows in transmission lines is formulated as a multiobjective optimization problem and calculated using a parallel vector evaluated particle swarm optimization (VEPSO) algorithm. Specifically, the contributions are modeled by particles of swarms whose positions are optimally determined while satisfying all multiobjectives and other physical and operating constraints. The VEPSO method is parallelized by distributing the swarms in a number of networked PCs. The proposed parallel VEPSO algorithm accounts for nonlinear characteristics of the generators and transmission lines. The applicability of the proposed parallel VEPSO algorithm in accessing the generator contributions is demonstrated and compared with analytical methods for four different systems: three-bus, six-bus, IEEE 30-bus, and 136-bus test systems. The experimental results show that the proposed parallel VEPSO algorithm is capable of obtaining precise solutions compared to analytical methods while considering nonlinear characteristics of the systems. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Analysis of radial distribution systems with embedded series FACTS devices using a fast line flow-based algorithm

    Publication Year: 2005 , Page(s): 1775 - 1782
    Cited by:  Papers (9)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (248 KB) |  | HTML iconHTML  

    Analysis of radial distribution systems with embedded series Flexible AC Transmission System (FACTS) devices is facilitated by a formulation of power flow equations with bus voltage magnitudes and line flows as independent variables. Since control variables such as the line and bus reactive powers figure directly in the formulation, handling the control action of FACTS devices in distribution systems is direct and easily implemented. Using the Breadth-First-Search (BFS), the bus incidence matrix of a radial distribution system is first rendered strictly upper diagonal, leading to reduced computational effort. All the common FACTS device models under steady-state conditions are easily incorporated in the new framework by a simple process of "variable swapping." Using IEEE standard systems, the line flow-based (LFB) formulation is shown to provide easy implementation with multiple series and shunt FACTS devices in the system and enable direct evaluation of the FACTS device ratings. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • An aggregate Weibull approach for modeling short-term system generating capacity

    Publication Year: 2005 , Page(s): 1783 - 1789
    Cited by:  Papers (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (296 KB) |  | HTML iconHTML  

    Deregulation of electricity markets is occurring all over the world. This trend introduces new risks and uncertainties into the electricity industry, the most significant being price risk. The spot price of electricity is highly volatile, and the ability to price risk management contracts on this commodity is contingent on a robust and realistic model of the underlying price process. One key driver of electricity spot price is the forced outages of generating plants in the system. The current paper describes a system aggregate model of short-term generating capacity that can be adapted to any generating system of interest. After describing the model, we test it using the IEEE Reliability Test System (RTS). View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Convexity of the set of feasible injections and revenue adequacy in FTR markets

    Publication Year: 2005 , Page(s): 1790 - 1798
    Cited by:  Papers (23)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (488 KB) |  | HTML iconHTML  

    The feasible set of power injections for the constrained power flow equations is nonconvex when practical transmission capacity and bus voltage limits are imposed. The projection onto the space of active power injections may be "close" to convex, but this is not sufficient to guarantee revenue adequacy for the settlement of financial transmission rights. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Transmission loss allocation through equivalent bilateral exchanges and economical analysis

    Publication Year: 2005 , Page(s): 1799 - 1807
    Cited by:  Papers (13)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (480 KB) |  | HTML iconHTML  

    A new loss allocation (LA) scheme based on the principle of equivalent bilateral exchanges (EBEs) is presented and compared with other available techniques. Formulation and results from extensive simulations including consistency tests show that the suggested methodology has several desirable properties: It is flow-based, requiring only a solved load flow for its implementation; it is not dependent on the choice of a slack bus; it is straightforward to apply; undesirable negative loss allocation is not produced; and low volatilities are shaped. An economic analysis with various LA methods is also carried out when these are integrated into a combined economic dispatch/load flow dispatch strategy, a likely scenario for LA in a real system. This combined dispatch strategy yields prices charged to the loads and rates received by the generators that account for loss allocation and loss supply. Results show that these economic indexes are very close to the marginal costs derived from an optimal power flow (OPF) approach with the advantage of reducing volatility. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Fuzzy financial decision-making: load management programs case study

    Publication Year: 2005 , Page(s): 1808 - 1817
    Cited by:  Papers (10)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (328 KB) |  | HTML iconHTML  

    This paper derives two fuzzy financial profitability models, namely, a least cost solution model and a cost-benefit analysis model, to evaluate the fuzzy financial profitability of load management alternatives. A straightforward vertex parameters' fuzzy mathematics operation using the function principle is derived as an alternative to the traditional extension principle and is applied to evaluate a number of different financial decision indexes. Compared to the extension principle, the function principle is simple to implement and is conceptually straightforward. The geometric moments of the fuzzy financial indexes are established in order to determine their relative ranking as part of a decision-making process. The performances of the proposed fuzzy financial models are verified by considering their application to two practical load management programs in Taiwan, namely, a cooling energy storage air conditioner and a cogeneration project. These investigations not only confirm that the results of the fuzzy financial models are consistent with those of the conventional crisp models but also demonstrate that the proposed models are more flexible, intelligent, and computationally efficient compared to the extension principle fuzzy mathematics approach. The developed models represent readily implemented possibility analysis tools for use in the arena of uncertain financial decision-making. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Market-clearing with stochastic security-part I: formulation

    Publication Year: 2005 , Page(s): 1818 - 1826
    Cited by:  Papers (104)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (344 KB) |  | HTML iconHTML  

    The first of this two-paper series formulates a stochastic security-constrained multi-period electricity market-clearing problem with unit commitment. The stochastic security criterion accounts for a pre-selected set of random generator and line outages with known historical failure rates and involuntary load shedding as optimization variables. Unlike the classical deterministic reserve-constrained unit commitment, here the reserve services are determined by economically penalizing the operation of the market by the expected load not served. The proposed formulation is a stochastic programming problem that optimizes, concurrently with the pre-contingency social welfare, the expected operating costs associated with the deployment of the reserves following the contingencies. This stochastic programming formulation is solved in the second companion paper using mixed-integer linear programming methods. Two cases are presented: a small transmission-constrained three-bus network scheduled over a horizon of four hours and the IEEE Reliability Test System scheduled over 24 h. The impact on the resulting generation and reserve schedules of transmission constraints and generation ramp limits, of demand-side reserve, of the value of load not served, and of the constitution of the pre-selected set of contingencies are assessed. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Market-clearing with stochastic security-part II: case studies

    Publication Year: 2005 , Page(s): 1827 - 1835
    Cited by:  Papers (17)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (464 KB) |  | HTML iconHTML  

    This paper analyzes the market-clearing formulation with stochastic security developed in its companion paper through two case studies solved using mixed-integer linear programming techniques. The generation and reserve schedules as well as the nodal prices of energy and security are assessed under various conditions such as a) line flow limits, b) when nonspinning reserve is excluded from the formulation, c) demand-side valuation of energy not served, d) generator ramping limits, and e) the set of pre-selected contingencies. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Unit commitment with primary frequency regulation constraints

    Publication Year: 2005 , Page(s): 1836 - 1842
    Cited by:  Papers (21)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (288 KB) |  | HTML iconHTML  

    The unit commitment problem with tertiary reserve requirements has been broadly studied. Such reserves, when needed, are centrally deployed with relatively slow time constants of the order of minutes. In contrast, the scheduling of units offering primary frequency regulation reserve deployable in a decentralized manner within seconds of a contingency has received relatively little attention. In this paper, we formulate and solve a multiperiod unit commitment that simultaneously accounts for both primary and tertiary reserve constraints. What makes this scheduling problem particularly challenging is the characteristic that primary frequency regulation reserves have a common single degree of freedom, namely, the system frequency deviation. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Probabilistic load-flow computation using point estimate method

    Publication Year: 2005 , Page(s): 1843 - 1851
    Cited by:  Papers (93)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (432 KB) |  | HTML iconHTML  

    A new probabilistic load-flow solution algorithm based on an efficient point estimate method is proposed in this paper. It is assumed that the uncertainties of bus injections and line parameters can be estimated or measured. This paper shows how to estimate the corresponding uncertainty in the load-flow solution. The proposed method can be used directly with any existing deterministic load-flow program. For a system with m uncertain parameters, it uses 2m calculations of load flow to calculate the statistical moments of load-flow solution distributions by weighting the value of the solution evaluated at 2m locations. The moments are then used in the probability distribution fitting. Performance of the proposed method is verified and compared with those obtained from Monte Carlo simulation technique and combined simulation and analytical method using several IEEE test systems. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Robust self-scheduling under price uncertainty using conditional value-at-risk

    Publication Year: 2005 , Page(s): 1852 - 1858
    Cited by:  Papers (46)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (296 KB) |  | HTML iconHTML  

    In a deregulated power industry, power producing companies bid in the hour-ahead and day-ahead power markets in an attempt to maximize their profit. For a successful bidding strategy, each power-producing company has to generate bidding curves derived from an optimal self-schedule. This self-schedule is commonly obtained from a profit-maximizing optimal power flow model based on predicted locational marginal prices (LMPs). However, at the time of self-scheduling, the predicted values of the LMPs are largely uncertain. Therefore, it is desired to produce robust self-schedules that can be used to lessen the risk resulting from exposure to fluctuating prices. In portfolio optimization theory, methods of risk management include Value-at-Risk (VaR) and conditional Value-at-Risk (CVaR). CVaR is known to be a more consistent measure of risk than VaR. In fact, whilst CVaR is the mean excess loss, the VaR provides no indication on the extent of losses that might be suffered beyond the amount indicated by this measure. This research proposes a method for robust self-scheduling based on CVaR. It will be shown that polynomial interior-point methods can be used to obtain the robust self-schedules from a second-order cone program. The obtained schedules provide a compromise solution between maximum profit and minimum risk. Simulation results on a standard IEEE bus test system will be used to demonstrate the scheduling model based on CVaR. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Supply function equilibrium bidding strategies with fixed forward contracts

    Publication Year: 2005 , Page(s): 1859 - 1867
    Cited by:  Papers (41)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (256 KB) |  | HTML iconHTML  

    During the last 15 years, the regulatory framework for the wholesale sector of the electricity industry has been replaced in many countries by market competition. In such an environment, electric firms compete through both spot market bidding and bilateral contract trading. Firms have to consider their forward contract positions when they make spot market decisions. In this paper, we propose a linear asymmetric supply function equilibrium (SFE) model with transmission constraints to develop firms' optimal bidding strategies considering forward contracts. The characteristics of firms' behaviors are analyzed under the induced equilibrium conditions. The model is applied to the real-time energy market of the Electric Reliability Council of Texas (ERCOT). The effects of forward contracts on the ERCOT market are evaluated. It is shown that the model is able to capture features of bidding behaviors in the ERCOT market. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.

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.

Full Aims & Scope

Meet Our Editors

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