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Power Systems, IEEE Transactions on

Issue 3 • Date Aug. 1988

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Displaying Results 1 - 25 of 82
  • Generation expansion planning including the renewable energy sources

    Publication Year: 1988 , Page(s): 816 - 822
    Cited by:  Papers (9)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (698 KB)  

    The authors study the long-term competitiveness of introducing renewable energy sources alongside the conventional generating units in a generation expansion plan by linking a short-term study and a long-term planning model. The short-term study is an extensive examination of the different combinations of the renewable energy sources which can operate with the conventional generating system for different objectives. These objectives are varied between two general strategies: the fuel-saver strategy and the peak-shaving strategy. In long-term planning, these combinations are considered as decision variables. For this purpose, a long-term generation expansion planning model is used to decide which strategy can be used and the capacity as well as the time of addition.<> View full abstract»

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  • Design of reliable measurement system for state estimation

    Publication Year: 1988 , Page(s): 830 - 836
    Cited by:  Papers (23)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (682 KB)  

    The authors propose an algorithm of optimal meter placement for the state estimation of power systems, which minimizes the total investment cost subject to a constraint of state estimation accuracy. The solution procedure is developed on the basis of the sequential meter addition/elimination method by reflecting the cost of individual meter installation and its contribution to the state estimation accuracy in the probabilistic sense. The sensitivity of the performance index to each meter installation is efficiently circulated with the use of recursive formulae. Selection ranking in the addition-elimination process is set up in terms of the performance index sensitivities.<> View full abstract»

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  • Residential cool storage: peak load reduction alternatives

    Publication Year: 1988 , Page(s): 837 - 843
    Cited by:  Papers (4)
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    The authors investigate alternatives for achieving a peak load reduction in the residential airconditioning sector from a technical and economic point of view. Several thermal energy storage technologies are assessed, considering different types of houses and storage schemes. If the utility offered an incentive of $300-400/kW of deferred peak, residential thermal energy storage would have a short payback time for new installations. The payback time for retrofits is unacceptable. Two-stage evaporative coolers can reduce peak power by 60%, with an extra cost of about one-fifth that of new peaking facilities. They can totally replace conventional air conditioning in some climates without any loss of comfort. High efficiency air conditioners can also reduce peak power but their incremental cost over standard units is higher than that of new peaking facilities.<> View full abstract»

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  • A contribution to the midterm scheduling of large scale hydrothermal power systems

    Publication Year: 1988 , Page(s): 852 - 857
    Cited by:  Papers (8)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (582 KB)  

    A concise mathematical model and nonlinear minimization algorithm were presented as a joint approach to set optimal midterm production targets for power systems with predominance of hydroelectric power generation. The algorithm uses the network structure of the problem and takes into account nondifferentiable points. The approach was successfully applied to the optimal midterm scheduling of a very large hydroelectric power system in southeastern Brazil. Further insight into the problem allowed the adoption of an optimization-simulation strategy which achieved a very good suboptimal solution with great savings in computer requirements. The main purpose of this research was to develop a working tool able to assist engineers in setting optimized midterm targets for the large power systems in Brazil, where more than 90% of the electric energy comes from hydraulic sources.<> View full abstract»

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  • Control variable adjustment in load flows

    Publication Year: 1988 , Page(s): 858 - 864
    Cited by:  Papers (8)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (568 KB)  

    A linear programming type approach is used to adjust all adjustable loadflow variables with respect to specified constraints. The technique is applicable to the Newton-coupled (and -decoupled) as well as the fast-decoupled load flows. The coordinated adjustment of all adjustable variables improves the convergence of the load-flow program and results in a reduction in the number of iterations with a minimal increase in the computation required by each iteration. No change to the structure of the Jacobian results when constrained variables violate their limits. The variable set remains the same throughout all of the iterations. This algorithm was implemented in the Ontario Hydro energy management system. Test results show a considerable reduction in the number of iterations and computation saving when major adjustments to the adjustable variables are required.<> View full abstract»

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  • Geographical load shift and its effect on interchange evaluation

    Publication Year: 1988 , Page(s): 865 - 871
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    An attempt is made to evaluate the amount of load shift that actually occurs on a large utility and to assess the error in the economic dispatch due to using B-constants developed neglecting the geographical load shift. This is done by a load shift simulation model to introduce load shifts in the development of B-constants. The B-constants are then used in a production costing/interchange evaluation program to investigate the effect of using B-constants developed with and without the load shift on evaluations of the worth, percent power delivered, overall system power losses, and production costs. A geographical load shift in excess of 10% over 24 h period has been shown to exist on a large electric utility. The production cost was found to be relatively insensitive to the use of the nominal B-constants. The errors in percent power delivered resulting for the use of nominal B-constants are similar to the errors in the worth.<> View full abstract»

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  • Availability analysis in a cable transmission system with repair restrictions

    Publication Year: 1988 , Page(s): 872 - 878
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (626 KB)  

    Single-system generating capacity adequacy analysis normally does not include recognition of transmission constraints or availabilities. These considerations are usually included in multiarea adequacy studies and in single system studies involving remote generating facilities connected to the system through either high-voltage AC or DC transmission. The availability of the transmission link can be critical to the overall system adequacy and to the benefit associated with the remote generation facility. The authors present a technique for modelling a transmission facility with repair restrictions. The example chosen is an underwater direct-current cable installation. The system is analyzed using a Markov model, and results are presented on time-dependent and steady-state unavailability, as well as on the common mode failure of trenches.<> View full abstract»

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  • A closed-loop quasi-optical dynamic braking resistor and shunt reactor control strategy for transient stability (of synchronous generators)

    Publication Year: 1988 , Page(s): 879 - 886
    Cited by:  Papers (18)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (578 KB)  

    A control strategy for dynamic braking resistor and shunt reactor is proposed for stabilization of electric generators subjected to large disturbances. The time optimal control is derived as a function of synchronous machine power, its rotor angular position, and speed deviation. The response for a single-machine system with the proposed control has been obtained using the steepest-descent method. The strategy has also been tested on two multimachine systems. Results indicate that the proposed strategy provides a simple and effective method of stabilization under transient emergency conditions. It is found that the strategy is very effective in controlling first swing instability.<> View full abstract»

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  • Implementation of the hypothesis testing identification in power system state estimation

    Publication Year: 1988 , Page(s): 887 - 893
    Cited by:  Papers (25)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (771 KB)  

    The authors consider the online implementation of a general, reliable and efficient bad-data analysis procedure for power system state estimation. It is based on hypothesis testing identification, which was previously proposed and subsequently improved by the authors. The procedure involves a sequential measurement error estimator along with adequate sparsity programming techniques. Both make the procedure easy to implement on any state estimator. A criterion for multiple noninteracting bad-data identification is also proposed, which is applicable to any bad-data analysis method. Simulations are reported on systems of up to 700 buses. A thorough comparison with classical methods is also included.<> View full abstract»

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  • Two reduced-order methods for studies of power system dynamics

    Publication Year: 1988 , Page(s): 894 - 899
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (534 KB)  

    The authors present two reduced-order methods, namely second-order aggregation and external system partition, for the analysis of power system dynamics. These methods are developed by the combination of the machine mode associate property with the aggregated model of multimachine systems. An 18-machine and a 9-machine power system are employed to numerically verify the basic concept and the methods. The verification results show that the first method is suited for the computation of all swing modes, while the second method is suited for computing the modes associated with a selected machine group.<> View full abstract»

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  • Analysis of interrelationships between photovoltaic power and battery storage for electric utility load management

    Publication Year: 1988 , Page(s): 900 - 907
    Cited by:  Papers (14)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (838 KB)  

    The impact of photovoltaic power generation on an electric utility's load shape under supply-side peak load management conditions is explored. Results show that some utilities utilizing battery storage for peak load shaving might benefit from use of photovoltaic (PV) power, the extent of its usefulness being dependent on the specific load shapes as well as the photovoltaic array orientations. Typical utility load shapes both in the eastern (at Rayleigh, NC) and in the western (at Hesperia, CA) parts of the USA are examined for this purpose. It is concluded that while photovoltaic power generation seems to present a bigger impact on the load of the western utility, both utilities will experience considerable savings on the size of the battery system required to shave the peak loads as well as in the night-time base capacity required to charge the battery.<> View full abstract»

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  • ALFA: automated load forecasting assistant

    Publication Year: 1988 , Page(s): 908 - 914
    Cited by:  Papers (31)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (682 KB)  

    ALFA, an expert system for forecasting short-term electricity demand is presented. ALFA is in operation at the Energy Management System center at Niagara Mohawk Power Corporation in upstate New York, generating, in real time, hourly load forecasts for up to 48 hours in advance. ALFA uses an extensive 10-year historical database of hourly observations of 12 weather variables and a rule base that takes into account daily, weekly, and seasonal variations of load, as well as holidays, special events, and load growth. A satellite interface for the real-time acquisition of weather data, and the machine-operator interface are also discussed.<> View full abstract»

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  • Stabilizing SSR oscillations with a shunt reactor controller for uncertain levels of series compensation

    Publication Year: 1988 , Page(s): 936 - 943
    Cited by:  Papers (11)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (595 KB)  

    The authors demonstrate how frequency-domain techniques based on I. Horowitz et al.'s (1986) quantitative feedback theory can be applied to the design of fixed-parameter controllers in power systems where the plant parameters have large uncertainties. They present the design of a controller for a shunt reactor to eliminate torsional shaft oscillations in a turbogenerator susceptible to subsynchronous resonance (SSR). The considered parameter uncertainty is the series capacitor compensation level, which has been assumed to vary between 12% and 76%. Simulated transients results of the uncontrolled/controlled system are depicted.<> View full abstract»

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  • Q'HARM-a harmonic power-flow program for small power systems

    Publication Year: 1988 , Page(s): 949 - 955
    Cited by:  Papers (7)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (548 KB)  

    The salient features of a harmonic power-flow program called Q'HARM, are described. Two kinds of harmonic-producing components, the line-commutated six-pulse bridge rectifier and the gaseous discharge lighting load supplied from nonsinusoidal sources, are accurately modelled in this program. Case studies involving the use of Q'HARM for a small power system including converters and gaseous discharge lamps are described. The results include the effect of filters and the computed values of telephone influence indices. It is also shown that the maximum values of telephone influence indices for the different harmonics occur at different points on any transmission line in the system.<> View full abstract»

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  • Stability tests and tuning the PSS at Battle River Plant of Alberta Power Ltd

    Publication Year: 1988 , Page(s): 956 - 962
    Cited by:  Papers (6)
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    The authors describe events leading up to field tests at the Battle River Plant in Alberta, Canada where rotor oscillations developed when an intertie transformer was disconnected during the normal course of system operation. Subsequent field tests to evaluate the inherent damping at the plant are described and details pertaining to commissioning a PSS (power system stabilizer) at this plant are included. PSS parameter selection is described in detail.<> View full abstract»

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  • Security constrained optimization-a case study (power system control)

    Publication Year: 1988 , Page(s): 970 - 977
    Cited by:  Papers (18)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (831 KB)  

    A comparison has been made between two approaches for steady-state bulk transmission system voltage analysis: a conventional approach using both a power flow program and an optimal power flow program (OPF), and a novel software tool. This program, the security-constrained optimization program (SCO), has been introduced and demonstrated to be effective in solving difficult capacitor planning studies. The solutions from the SCO not only optimize the precontingency system conditions as an OPF, but the effects of all of the postcontingency constraints are included. All existing system control variables are set at their optimal preventive mode values by the program. The algorithm is efficient, requiring little overhead per contingency beyond a conventional OPF solution. The results of a comparison between the SCO and a conventional study solution show that the SCO computes accurate solutions in a fraction of the time required using conventional means.<> View full abstract»

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  • Comparative analysis and study of the dynamic stability of AC/DC systems

    Publication Year: 1988 , Page(s): 978 - 985
    Cited by:  Papers (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (595 KB)  

    The authors present an approach for the dynamic stability analysis of power systems possibly including DC facilities and static VAr equipment. To illustrate a typical application of the computer program described, a system is selected which includes a DC tie interconnecting two large networks, and static compensators which are used to regulate AC voltages. Synchronous generators in the network on the inverter side are dedicated to the interconnection. Regulators to damp oscillations of the dedicated generators are investigated with eigenvalue analysis and Bode plots, which are automatically generated by the program on request.<> View full abstract»

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  • Residential end-use load shape estimation from whole-house metered data

    Publication Year: 1988 , Page(s): 986 - 991
    Cited by:  Papers (8)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (658 KB)  

    A methodology for estimating end-use load shapes using hourly whole-house metered load data, household demographic survey data, and weather data (temperature) is presented. Although the focus on the residential sector, the techniques developed can also be applied to the industrial and commercial sectors. The load shape for each member of a set of customers is first compressed into a small number of representative parameters. These are then related to customer characteristics, such as appliance holdings, demographic and socioeconomic data, and information on the dwelling. The results obtained show that the overall methodology provides an effective means for end-use load shape modeling and estimation.<> View full abstract»

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  • A topology processor that tracks network modifications

    Publication Year: 1988 , Page(s): 992 - 998
    Cited by:  Papers (26)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (606 KB)  

    Software considerations and test results are given for a topology processor that can track the changes in the network over time. It is expected that by knowing the changes from one cycle to the next, certain steps in the network solution can be avoided or replaced with steps requiring significantly less computation. The steps of particular interest are the ordering and factoring of the network solution matrix. In the operator training simulator, where solution time is critical, the simulation computation slows down when changes take place in the network, but the presented topology processor may provide the means to keep up with real time. In the security analysis real-time time sequence, computation can be saved in the state estimator if its tracking topology processor is used. The use of this topology processor modifies the solution of the tracking mode. For large topology changes, it is the same as the conventional tracking mode. But for the more common small topology changes, the matrices are not rebuilt and considerable computation time is saved.<> View full abstract»

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  • An efficient algorithm for the design of decentralized output feedback power system stabilizer

    Publication Year: 1988 , Page(s): 999 - 1004
    Cited by:  Papers (8)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (495 KB)  

    An algorithm for the design of decentralized output feedback stabilizers for large-scale electric power systems is proposed. In the proposed approach, the generators which are most effective for stabilizer applications are first identified by using participation factors. Then an efficient algorithm based on decentralized pole assignment is proposed for the determination of the parameters of the power-system stabilizers which, due to the difficulty associated with communication among the geographically dispersed generating stations in a large power system, are essentially decentralized compensators using local generator outputs as their feedback signals. The proposed method is computationally efficient and can be applied to any large-scale system. The simplicity and effectiveness of the proposed method are demonstrated by an example of stabilizer design for a practical power system.<> View full abstract»

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  • The incorporation of HVDC equations in optimal power flow methods using sequential quadratic programming techniques

    Publication Year: 1988 , Page(s): 1005 - 1011
    Cited by:  Papers (14)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (540 KB)  

    The author presents the formulation and solution method of an optimal power flow problem using a sequential quadratic programming technique for an AC-DC power system with one or more multiterminal DC systems. The algorithm developed has been tested on a number of sample AC-DC systems. The convergence characteristics, insofar as the number of the major iteration goes, is comparable with the Newton-Raphson approach. The economic advantage of being able to coordinate the DC system power transfers is illustrated by numerical examples based on the modified IEEE 30 and 118 bus systems.<> View full abstract»

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  • A dual augmented Lagrangian approach for optimal power flow

    Publication Year: 1988 , Page(s): 1020 - 1025
    Cited by:  Papers (7)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (432 KB)  

    The authors present a method for solving the active and reactive optimal power-flow problem. The method is based on nonlinear programming techniques combining dual and penalty approaches. The classical Langrangian is defined for both equality and inequality constraints. The function is then augmented by penalty terms for all constraints and it is minimized by Newton's method. An intrinsic multiplier updating rule eliminates the necessity of increasing the penalty factors to very large values. The method unifies the treatment equality and inequality constraints. It also avoids the critical aspects present in the determination of the binding constraints set.<> View full abstract»

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  • Transmission loss evaluation for electric systems

    Publication Year: 1988 , Page(s): 1026 - 1032
    Cited by:  Papers (10)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (651 KB)  

    Transmission losses in electric system are shown to be a function of customer load, general schedules, imports, exports, and wheeling, with various portions of the system being sensitive to one or more of these parameters. A methodology to capture the majority of transmission losses through load flow modeling is presented. In those instances where special consideration is required, i.e., components where losses are a function of load and remote generation on radial lines, additional information is presented. Methods of correctly incorporating transformer iron and copper losses and transmission-line corona losses in loss analyses are discussed. In addition, it is demonstrated that the use of the empirical equivalent hours loss factor is inappropriate for most applications.<> View full abstract»

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  • Dynamic load modeling in large scale stability studies

    Publication Year: 1988 , Page(s): 1039 - 1045
    Cited by:  Papers (21)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (520 KB)  

    Mixture data obtained from billing information have been used with the LOADSYN program to develop dynamic load models for large-scale studies. The impact of dynamic load modeling is studied under different scenarios using an Ontario Hydro 4000-bus basecase. The sensitivity of the results to the extent of dynamic modeling is assessed by using up to 449 dynamic models. The field measurements of a tornado event are used to weigh the accuracy improvement offered by dynamic models against their extra computation burden.<> View full abstract»

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  • Forecasting fuel requirements uncertainty

    Publication Year: 1988 , Page(s): 1046 - 1051
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    The authors describe the development of the Fuelburn model for generating reliable probabilistic forecasts. This model incorporates the many related uncertainties affecting fuel requirements, captures the characteristics of large and complex utility systems, and produces output in a form directly useful for supporting fuel and system decisions. A utility application of the Fuelburn model is discussed. It is concluded that Fuelburn's capabilities can help utilities design operating strategies that deal flexibly with the considerable risks in the utility environment.<> 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