In general, all CSC configurations improve voltage, small signal, and .... zuela-Electricidad de Carcas; General Electric; Universidad Central de. Venezuela ...
lation damping. In general, all CSC configurations improve voltage, small signal, and transient stability margins of the system. The performance of the individual devices resulting from CSC configurations and their capabilities in the studied cases is presented. It is shown that the CSC in conjunction with three fixed capacitor banks at three other substations can increase the system power transfer limit by up to 31 OMW. Keywords: FACTS, CSC, STATCOM, SSSC, UPFC, IPFC, voltage security, eigenvalue analysis, transient stability. Preprint Order Number: PE-OIOPRS (04-2002) Discussion Deadline-: September 2002
Transi'Lent Security iDspatch for the Concurrent OptiIzation of lural Postulated Contingencies Bruno, S.; De Tuglie, E.; La Scala, M. Author Affiliation: Politecnico Di Bari, Bari, Italy Abstract: The implementation of a transient security dispatch (TSD) algorithm for real-time applications is presented. The algorithm, based on the generalized reduced gradienit (GRG) method, processes collectively a set of contingencies in order to ensure transient stability for all postulated cases. The massive computation has been decomposed on a cluster of workstations, exploiting the decoupled nature of the GRG method and the benefits of distributed computing. The feasibility of the implementation is shown through tests on a realistic-sized test network.
Keywords: Transient security dispatch, dynamic security assessment, preventive control, distributed computing. Preprint Order Number: PE-184PRS (04-2002) Discussion Deadline: September 2002
Robust Decentralized Turbine/Governor Control Using Linear Matrix Inequalities Siljak, D.D.; Stipanovic, D.M.; Zecevic, A.I. Author Affiliation: Santa Clara University, Santa Clara, CA Abstract: A new scheme is presented for the robust decentralized stabilization of multimachine power systems based on linear matrix inequalities (LMI). The proposed method is computationally efficient and can easily incorporate additional design requirements. The efficiency of this control strategy is illustrated on the IEEE 39 bus system for a variety of large disturbances. Experimental results indicate that transient stability can be significantly improved with this approach. Keywords: Robust control, linear matrix inequalities, power systems, nonlinear systems, Lyapunov stability. Preprint Order Number: PE-263PRS (04-2002) Discussion Deadline: September 2002
Application of Structure Preserving Energy Margin Sensitivity to Determime the Effectiveness of Shunt and Serles FACTS Devices Shubhanga, K.N.; Kulkarni, A.M. Author Affiliation: IIT Bombay, Bombay Mumbai, India Abstract: This paper presents a structure preserving energy margin
sensitivity based analysis to determine the effectiveness of FACTS devices to improve transient stability of a power system. A structure preserving energy model, which retains the topology of the network, is used to derive simple analytical expressions for improvement in energy margin due to series or shunt compensation. The expressions are in terms of current magnitude through a line for series compensation and voltage magnitude at a bus for shunt compensation. Therefore, these expressions are easy to interpret in the context of applying compensation at strategic locations. The proposed method is applied to a four machine, 10 bus system and a 10 machine, 39 bus New England system, and its validity is demonstrated through time domain simulations both for classical and detailed model with AVR for generators. Keywords: Power system transient stability, structure preserving energy function, energy margin, FACTS devices.
IEEE Power Engineering Review, July 2002
Preprint Order Number: PE-421PRS (04-2002) Discussion Deadline: September 2002
Power System
Operat'ions
Market Plurality and Manipulation: Performance Comparison of Independent System Operators Nakashima, T.; Nimura, T. Author Affiliation: University of British Columbia, Vancouver,
British Columbia, Canada Abstract: In this paper, the authors present three different models that represent the coordinating functions of existing independent system operators (ISOs) and discuss their advantages and disadvantages. Max-ISO is a centralized operator based on the pool model, and mm-ISO is a decentralized operator based on the bilateral model. Mix-ISO is positioned in-between, having multiple power exchanges or bilateral contracts. The performance of the different ISOs is compared by the total social welfare and the vulnerability to market manipulation. A numerical example is presented to compare the performance of different ISOs. The max-ISO is considered to be the most efficient model theoretically, but it does not necessarily provide the best market in terms of vulnerability to market manipulation. Keywords: Deregulation, ISO, congestion, social welfare, power exchange market, and market manipulation. Preprint Order Number: PE-318PRS (04-2002) Discussion Deadline: September 2002
Transition to an Electricity Market: A Model for Developing Countries Leeprechanon, N.; David, A.K.; Moorthy, S.S.; Liu, F. Author Affiliation: Thammasat University; Hong Kong Polytechnic University; Royal Melboume Insutitute of Technology; Southeast University Abstract: Market-oriented restructuring of the electricity supply industry (ESI) in the West has led to a realization of the need for reform and competition in developing countries as well. However, there are fundamental differences between the two cases regarding the maturity of the ESI structure, economic priorities, and the role of the state in development. This paper, therefore, synthesizes a model of reform that is sensitive to these realities. Consequently, the outlook is different from the prevailing tendency to simply transpose experience from elsewhere. The core issue that we identify is the approach to the transmission system. Thailand, since it is of medium size and reform oriented, is used as the main reference point, but short sections on Sri Lanka and China are included to widen the relevance of the discussion. Keywords: Power market, transmission entity, transition, developing countries, Asia, privatization Preprint Order Number: PE- 157PRS (04-2002) Discussion Deadline: September 2002
Standard Levels of Energy Losses in Primary Distribution Circuits for SCADA Application Khodr, H.M.; Molea, J.; Garcia, I.; Hidalgo, C.; Paiva, P; Yusta, J.M.; Urdaneta, AJ. Author Affiliation: Universidad Simon Bolivar; AES Venezuela-Electricidad de Carcas; General Electric; Universidad Central de Venezuela; Universidad de Zaragoza Abstract: The reduction of energy losses in distribution systems is an important issue during planning and operation with important technical and economical implications. The standard or normal level of energy losses in primary distribution circuits represents an important indicator for the planning and operation of electrical distribution circuits. It de57
pends upon a number of parameters and variables such as the nominal circuit voltage, the installed transformer capacity, the number of transformation points, the load level, etc. In this article the application of a statistical procedure for the determination of the standard levels of energy losses in primary distribution circuits is proposed. The methodology is applied to a subset of 312 primary distribution circuits out of the total of 819 circuits of the electrical distribution network that serves the city of Caracas and its surroundings. The resultant standard upper and lower levels of energy losses are presented for the 15 different groups of circuits that were formed by the statistical procedure. These limits are used online for the identifleation of those distribution feeders with an operating level of energy losses out of the standard levels of its correspondent statistical group, as candidates for the application of energy losses reduction measures. The developed application software is presently running on-line at the distribution energy management system of the of C.A. La Electricidad de Caracas-AES Venezuela. Keywords: Distribution circuits, energy losses, standards, statistics. Preprint Order Number: PE-487PRS (04-2002) Discussion Deadline: September 2002
Power System Planning and Implementation
Unreliability Cost Assessment of an Electric Power System Using Reliability Network Equivalent Approaches Wang, P; Billinton, R.; Goel, L. Author Affiliation: Nanyang Technological University, Singapore; University of Saskatchewan, Saskatoon, Canada Abstract: Unreliability cost evaluation of an entire power system provides a set of indices that can be used by a system planner to balance the investments in different segments of the system in order to provide acceptable load point reliability. This paper utilizes reliability network equivalent techniques to evaluate the customer load point unreliability cost indices caused by outages in different segments of the power system. The equivalent multistate generator (EMG), the equivalent mutistate lateral section (EMLS), and the equivalent multistate series element (EMSE) are introduced. The percentage distribution of unreliability costs for system segments is determined to find the weak segments in the system. A test system is analyzed to illustrate the application of these techniques. Keywords: Network equivalent, unreliability cost, reliability worth Preprint Order Number: PE-374PRS (04-2002) Discussion Deadline: September 2002
Performance Evaluation of Electric Distribution Utilities Based on Data Envelopment Analysis Pahwa, A.; Feng, X.; Lubkeman, D. Author Affiliation: Kansas State University, Manhattan, KS; ABB, Inc., Raleigh, NC Abstract: In this paper, a method for benchmarking performance of electric distribution utilities based on data envelopment analysis (DEA) is presented. Basic theory of DEA is followed by case studies addressing performance analysis of the 50 largest (based on MWh sales) electric distribution utilities in the U.S. The results include performance efficiency, gaps in inputs and outputs of inefficient utilities, sensitivity-based classification of utilities, and a gap report. Also, peer-to-peer comparison of inefficient and efficient utilities is provided. Based on these results, inefficient utilities can develop strategic plan to improve perfortnance. Keywords: Strategic planning, decision making, data envelopment analysis, performance benchmarking, gap analysis. Preprint Order Number: PE-005PRS (04-2002) Discussion Deadline: September 2002 58
A Linear Programming Methodology for the Optimization of Electric Power Generation Schemes Khodr, H.M.; Gomez, J.C.; Barinique, L.; Vivas, J.H.; Paiva, P; Yusta, J.M.; Urdaneta, AJ.
Author Affiliation: Universidad Simon Bolivar; INELECTRA C.A.; Universidad de Zaragoza Abstract: A mathematical model, based upon the application of a linear-integer programming algorithm, is presented for the optimum selection of independent electric power generation schemes in industrial power systems, taking into account reliability considerations. The problem is formulated as a mathematical programming problem, considering investment costs, fuel costs, operation and maintenance costs, power balance, maximum and minimum limits on the generated power of the units, as well as reliability considerations such as the unavailability of the generation scheme. These considerations include assumptions taken and simplifications performed in order to obtain an accurate enough linear model. The problem is solved using a conventional branch and bound algorithm for linear-integer programming, yielding to the optimum number of units, as well as the correspondent size and type. Results are presented for the application of the proposed methodology to a real case of an industrial power system. The technique is proved as a valuable tool for the planning engineer. Keywords: Power generation planning, power generation economics, optimization methods. Preprint Order Number: PE-020PRS (04-2002) Discussion Deadline: September 2002
Wheeling of Power Under Deregulated Environment of Power System: A Bibilographical Survey Sood, YR.; Padhy, N.P; Gupta, H.O. Author Affiliation: Indian Institute of Technology Abstract: The power industry is moving rapidly from regulated conventional setups to a deregulated envirorment. There is an urgent need to keep a track of intemational experiences and activities taking place in this emerging field. This paper gives a bibliographical survey and general background of research and development in the field of power system wheeling under a deregulated environment based on over 170 published articles. Wheeling in general and the establishment of wheeling rate in particular are subjects of extensive debate today. This will be very useful for all countries, especially those developing countries that are moving towards the unbundling of electricity supply industry. The collected literature have been divided into many sections so that new researchers do not face any difficulty obtaining literature, particularly in the area of wheeling of power under deregulated environments. Keywords: Wheeling, deregulation, congestion, privatization, independent power producers, nonutility generation, available transfer capability, transmission open access, unbundilug, independent system operator.
Preprint Order Number: PE-109PRS (04-2002) Discussion Deadline: September 2002
Application of Evolutionary Algorithms for the Planning of Urban Distribution Networks of Medium Voltage Diaz-Dorado, E.; Cidras, J.; Miguez, E. Author Affiliation: Universidade De Vigo
Abstract: An important issue in power distribution nowadays is the need to optimize medium-voltage networks serving urban areas. This paper shows how an evolutionary algorithm can be used as the basis for the type of efficient algorithm such optimization demands. The search for an optimal network solution will be restricted to a graph defined from the urban map, so each graph branch represents a trench. The solution space (networks) is assumed with "loop feeder circuits": networks with two electrical paths from the hv/mv substations to the customers. In the optimization process, the investment and loss load IEEE Power Engineering Review, July 2002
