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Electric Utility Deregulation and Restructuring and Power Technologies, 2000. Proceedings. DRPT 2000. International Conference on

Date 4-7 April 2000

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  • DRPT2000. International Conference on Electric Utility Deregulation and Restructuring and Power Technologies. Proceedings (Cat. No.00EX382)

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  • Author index

    Page(s): 685 - 688
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    Freely Available from IEEE
  • An intelligent tool for maintenance scheduling of distribution systems

    Page(s): 215 - 220
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    This paper presents an expert system developed for a distribution company with the intention of helping the engineer responsible for the requests for equipment outage for preventive maintenance or network expansion. Usually, in order to decide whether these requests should be approved or not, the engineer verifies the possibility of transferring the load during outage considering constraints, such as which and what kind of consumers will be affected by the service, and whether they should be warned about the interruption, or if the timing is inadequate for them, etc.. The support of an intelligent system will allow the engineer to consider many other aspects, for instance, whether it is possible to join two requests in one interruption and, specially, to monitor the reliability indices of the area when the service under analysis is performed. The main objective is to minimise the frequency and duration of interruptions for preventive maintenance avoiding penalties from the regulatory agency View full abstract»

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  • Hedging new electricity market risks in the concentrated market-places in the European Union

    Page(s): 587 - 591
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    There is an on-going liberalization and deregulation process in the electricity markets worldwide. This process has created new actors and new risks in the market. The risks mainly consist of the price risk, counterparty risk and the system risk. In this study, the authors have compared the hedging methods offered by two electricity pools in the European Union, the Nordic Electricity Exchange Nord Pool and the Electricity Pool of the United Kingdom. Hedging methods available at the moment are the financial instruments (futures, forwards and options), special hedge contracts, clearing house services and security payments. The principle of hedging is similar in both the studied electricity pools, but methods do vary. This is mainly due to the fact that these pools are of a different nature View full abstract»

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  • GA optimisation of rule base in a fuzzy logic control of a solar power plant

    Page(s): 221 - 225
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    A genetic algorithm (GA) is formulated to optimise the rule base of a fuzzy logic controller (FLC) in a solar power plant. The rule base embodies an empirical set of 49 `if-then' rules. The influence of each rule is scaled by a weighting factor which is encoded in the gene of a chromosome. The entire chromosome encodes all of the 49 weighting factors. Evaluation of the fitness of the chromosome is based on the response time of the plant. Considerably improvement of plant performance is shown after some 80 generations of evolution of the chromosome View full abstract»

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  • The evaluation of confidence limit on LOLP for multi area system

    Page(s): 592 - 595
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    Since the forced outage rates (FOR) of generating plants is actually uncertain, LOLP must be a random variable. This paper presents an effective simulation method for calculating the value of LOLP of a multi area system by considering uncertainties both on FOR and load forecasting. There are no exact values of LOLP in a random system, and therefore one has to evaluate its confidence interval. The interval estimate of LOLP gives the upper and lower values of LOLP, so that the LOLP lies between these limits with a specified probability. These upper and lower values of LOLP may be interpreted to be confidence limits on the expected value of LOLP. The simulation results were tested by statistical goodness-of-fit tests and the gamma distribution was found to provide a good fit to the data produced by the Monte Carlo simulations for the sample system View full abstract»

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  • Security standards and contribution made by embedded generation

    Page(s): 626 - 631
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    This paper reviews the apparent strengths and weaknesses of existing security standards in respect of the assumed contribution that embedded generation can make to the security of power systems and the loads attached to it. It first outlines the background and weaknesses of these standards together with the need for alternative approaches that can be used to measure the contribution of embedded generation to security. Feasibility studies of two such alternative approaches indicate a new way forward in creating appropriate security standards in networks containing all forms of embedded generation. The need for these are very important since the use of embedded generation (including renewables and other forms) is expected to increase dramatically in the future with a contribution of up to about 15% of total capacity being forecasted View full abstract»

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  • Application of auction results to power system expansion

    Page(s): 142 - 146
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    Auction results reflect the market condition at the time the auction is performed. The market condition consists not only of electricity demand and supply at that period, but also includes the transmission network condition at that period. The network condition plays a major role in the auction results. If some transmission lines are congested, it can interfere with the desired operation of the network; e.g., block the transaction from the inexpensive sources to the high demand areas. Because of these reasons, an independent contract administrator (ICA) may wish to consider auction results when making decisions related to power system expansion. This work outlines a framework of applying a decision analysis approach to the auction results in selecting the expansion plan for the system View full abstract»

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  • Steady-state modelling of thyristor controlled series compensator for phase domain load flow analysis of electric networks

    Page(s): 191 - 196
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    The goal of this paper is to develop a steady-state mathematical model of the new generation of power electronic-based plant components emerging as a result of the newly developed concept of flexible AC transmission systems (FACTS), namely thyristor controlled series compensator (TCSC). The modelling is carried out in the phase domain considering the TCSC physical structure. A polyphase power flow program based on Newton algorithm is developed in order to implement the proposed model. Analysis of the TCSC performance is carried out in both balanced and unbalanced power network operating conditions. This kind of analysis will allow quantifying the many economical and technical benefits this technology promises, as well as examining the applicability and functional specifications of the controller View full abstract»

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  • The use of tangent vectors for voltage collapse analysis

    Page(s): 449 - 452
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    Nowadays, it has been observed that the load demand increase in many electrical systems has not been matched with the necessary investments to upgrade the power generation and transmission. This has caused such systems to work more stressed leading to voltage stability problems. The understanding of the events leading to the voltage collapse phenomenon has been the aim of many researchers which resulted in the development of a great number of simulation programs. Many tools have been chosen to help determine the weakest system bus with less computational effort as possible in order to enable a quick response regarding the search of preventive measures to improve the system voltage stability level. In this sense, eigenvectors and tangent vectors are very useful sources of information. These two elements combined allow the determination of the critical bus and the generators which most influence the system stability. These analyses will allow the operators to make decisions on what variables to work on in order to avoid the voltage collapse View full abstract»

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  • VAr planning of distribution feeders by GM(1,N) model

    Page(s): 268 - 272
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    The major research method about VAr planning of distribution feeders in the past was the nonlinear programming method, and it has been published in many papers. However, in the past twenty years, new methods have been discussed, such as genetic algorithms, fuzzy methods and neutral network methods. Although the results are all quite good, we still want to find a new method to solve the VAr problem. Therefore, in this paper, we first present the GM(1,N) model, which is one of the most important topics in the grey system theory, to do the VAr planning in distribution feeders. After the model has been presented, we use a small system in the Taiwan Power System (Taipower System) as our example to implement the new method for VAr planning View full abstract»

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  • Voltage security considerations in an open power market

    Page(s): 278 - 283
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    The deregulation of the electric power industry in Europe is the major issue nowadays. The new environment raises questions concerning all sectors of the electric power industry. Nevertheless, the transmission system is the key point in market development since it puts constraints to the market operation due to technical requirements. Especially, in systems having weak connections among areas, congestion problems arise due to line overloading or to voltage security requirements. This paper focuses on topics concerning voltage security in a deregulated power market and related market issues. Results by the application of the proposed methodology in the Greek Electric Power System (EPS) are presented View full abstract»

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  • A feasible model of open electricity supply industry in Hong Kong

    Page(s): 632 - 635
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    Following proven experience on electricity de-regulation over the world, Hong Kong is poised to follow suit and prepare to have a more open electricity market. A feasible model of an open electricity market is proposed in this paper. In the paper, the basic rationale for setting up the proposed model which includes the regulating mechanism, monitoring organization, power exchange and scheme of pricing, metering and data collection, etc. is outlined View full abstract»

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  • Phase balancing for a self-excited induction generator

    Page(s): 602 - 607
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    This paper describes a phase-balancing scheme for a three-phase self-excited induction generator (SEIG) which supplies single-phase loads. It is demonstrated that perfect phase balance can be achieved using a modified Steinmetz connection, provided that the positive-sequence impedance angle of the SEIG exceeds 2π/3 rad. From the phasor diagram, the conditions for perfect balance are established. It is found that the values of phase converter elements as well as the load resistance are functions of the positive-sequence admittance and impedance angle of the induction generator. Using the method of symmetrical components, the input impedance of the SEIG can be determined and solution of the equivalent circuit is formulated as a function minimization problem. The pattern search method of Hooke and Jeeves is employed for minimizing the impedance function, which enables the machine variables to be determined. It is further shown that, when the auxiliary load resistance is absent, perfect phase balance can still be achieved when the impedance angle of the SEIG is equal to 2π/3 rad. Feasibility of the phase-balancing schemes and the validity of the theoretical analysis are confirmed by experiments on a 2.2 kW induction machine View full abstract»

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  • Fuzzy logic based SVC for power system transient stability enhancement

    Page(s): 453 - 458
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    This paper presents an application of fuzzy control to determine the control signal of static VAr compensator (SVC) for improvement of power system stability. This compensation scheme relevant to flexible AC transmission systems (FACTS) technology is used worldwide to improve system dynamic performance. The device increases power transfer and improves the damping of electromechanical oscillations when used in transmission systems. The proposed controller for the SVC is based on fuzzy set theory and is called fuzzy logic controller (FLC). Input signals for the FLC are chosen as generator speed deviation and accelerated power. The quantity of reactive power supplied/absorbed by SVC is determined based on the two input signals at each sampling time. The control signal is calculated using fuzzy membership functions. The effectiveness and feasibility of the proposed control method is demonstrated by a one machine infinite bus system View full abstract»

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  • Economies of scale and optimal selection of hydroelectric projects

    Page(s): 284 - 289
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    The authors define a purely hydroelectric power system as a power system consisting almost entirely of hydroelectric generating stations, where thermal backup stations are used only intermittently in dry periods. The expansion process for such a system consists of selecting from a set of available projects with certain investment cost and generating capacity characteristics. One of these characteristics is a measure of the economies of scale (EOS). In this paper, the EOS for hydroelectric projects are investigated by using available cost and capacity data from the Icelandic power system. Furthermore the tradeoff between large and small projects is investigated by weighting the lost sales during the period of excess capacity against the benefit of using larger projects due to the EOS. The optimum is shown graphically and depends on the demand growth and interest rate. The authors investigate a hypothetical example where a series of generating facilities can be replicated at will to satisfy a linear general demand. These results are then expanded by assuming a stepwise demand associated with each project to satisfy bulk energy demand such as that of an energy intensive industry. The results are illustrated graphically in a case study using data from the “purely hydroelectric” Icelandic power system View full abstract»

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  • Experiences at the electricity control centers in El Salvador and Nicaragua in the frame of the Electricity Industry Reforms

    Page(s): 425 - 430
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    This paper gives a brief description of the concepts and goals of the electricity industry reforms process with some references about the Central America context. It presents a brief description of the operation of the electricity control centers in the competitive market as a result of such electricity industry reforms, where two main functions are treated, the system operation and the power exchange administration. Two Central American countries, El Salvador and Nicaragua, are specifically treated in this paper. The electricity industry organisation is given as context for both countries. The electricity control center operation is explained for each of these countries. The operations of the electricity control center in each country are presented using a novel functional model, based in intuitive graphical representation of the information flow. With this model approach the functions change under demands, because the reforms, can be added, placed, linked and documented. Some conclusions about the induced changes at the electricity control centers in El Salvador and Nicaragua are considered View full abstract»

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  • An approach to estimate the cost of disturbance to participants of electricity markets

    Page(s): 482 - 487
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    The Finnish electricity market participates in the Scandinavian markets, Nord-Pool. The Finnish market is free for dealers, producers and consumers of electricity. Electricity is sold and bought in a market place, which is physically the transmission network. The Finnish transmission network belongs to a single independent company called Fingrid. It has the full responsibility of the Finnish power transmission system. The aim of this work was to determine the costs of disturbances of the transmission network to the participants of electricity markets. Costs of altered power flows because of electricity markets are also discussed. It was found that the costs of the participants depend on how the system operator reacts to the disturbance. In the Finnish power system consumers will usually experience no costs due to the disturbance because of meshed network and counter trade method preferred by the system operator. The costs to the producers and dealers are also low because of the counter trade method. The Network Company will lose the cost of reparation, additional losses and cost of regulation power because of counter trades. If power flows are rearranged drastically because of electricity markets, the only way to fulfil the needs of free markets is that the Network Company buys regulation power for short-term problems and reinforces the network in the long-term situations. This is done if the network cannot be operated safely in the altered power flow situation View full abstract»

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  • Computational and experimental investigation of VSI-PWM frequency converter performance in the context of power quality

    Page(s): 78 - 83
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    This paper aims to present investigation results related to PWM-VSI frequency converters performance under nonideal voltage supply conditions. Besides computational analysis using a proper model in the Saber simulator, practical studies are also given. The later uses a commercial type of converter and a programmable power quality disturbances source. Using both the theoretical and practical way of considering different items of nonideal supply, different situations are simulated to estimate the equipment behavior. The paper focuses the characteristic and noncharacteristic harmonic spectrum generation for both the input current and the output voltage View full abstract»

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  • Using battery energy storage system in a deregulated environment to improve power system performance

    Page(s): 614 - 619
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    This paper embodies recent work at the Hong Kong Polytechnic University on the application of energy storage in general and BESS in particular in four areas: control of active and reactive power, load leveling, power quality improvement and power flow controller. The research aims at developing novel strategies for controlling those dynamic problems and investigating the advantages and limitation of BESS for the applications investigated. This paper discusses the hardware configuration and software technologies currently being used to implement some of the above objectives, in particular, the fast control of active and reactive power demand and generation when a BESS is connected to the grid. The proposed three-phase multi-purpose BESS will provide active and reactive power independent of the supply voltage with excellent power quality in terms of its waveform View full abstract»

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  • Comparison of various neural network models applied to adaptive distance protection

    Page(s): 244 - 250
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    This paper elaborates settings and modification of the operating characteristic of adaptive distance relays which protect a transmission line between two terminals. Operating characteristic should have such shape to satisfy all conditions in the power system. However it is known that there is no combination of characteristics which can satisfy all possible conditions. So the only solution is modification of the operating characteristic. Solution of this problem involves two types of neural networks, multilayered perceptron and the self-organizing neural network, the so called Kohonen network. Here the authors consider a two-terminal transmission line, confirm that fault resistance and location of faults can produce erroneous relay function and finally suggest ways to ensure the generation of the correct signal for relay operation. With the simple simulation, the authors present the advantages of the particular models and the credibility of the developed models View full abstract»

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  • Reactive power planning and operating in the deregulated power utilities

    Page(s): 72 - 77
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    In the deregulated power industry, questions such as: Who is responsible for the reactive power compensation?; Are the reactive power service providers, especially generation owners, entitled to get paid to recover their costs?; Do consumers need to pay for reactive power loads?; What roles should generators play in reactive power compensation?; etc., are often raised. This paper intends to provide answers by means of examples. This proposal suggests that the reactive power compensations are made by distribution and transmission companies and the generator reactive power capacities are reserved for contingencies. The reactive power compensation at distribution level is to keep load site power factor near unity. The transmission companies need to provide the required reactive power to ensure the proper power delivery in transmission network under normal conditions. Generators operate nearly at unity power factor under normal conditions. For contingencies, generators are responsible for the additional reactive power requirements View full abstract»

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  • New parameterization schemes for the continuation load flow method

    Page(s): 179 - 184
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    The conventional load flow methods are considered to be inadequate to obtain the maximum loading point (MLP) due to ill-conditioning problems at and near this critical point. As far as the Newton method is concerned, the Jacobian matrix becomes singular at MLP. Continuation methods are efficient tools for solving this kind of problem, since different parameterizations are used in order to avoid such ill-conditioning problems. In this paper new parameters are presented and tested, namely the total power losses (real and reactive), the power at the slack bus (real or reactive); and the reactive power at generation buses. The results obtained with the new approach for the IEEE test systems (14, 30, 57 and 118 buses) show that the characteristics of the conventional method are not only preserved but also improved. In addition, it is shown that the proposed method and the conventional one can be switched during the tracing of PV curves in order to efficiently determine all points with few iterations View full abstract»

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  • Design of STATCOM multivariable sampled regulator

    Page(s): 1 - 6
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    This papers reports a case of negative interaction between the AC and DC voltage control of a STATCOM (static synchronous compensator) installed in a power system. A novel technique to design a decoupled multivariable sampled regulator (SR) for multi-input multi-output (MIMO) systems is applied for the co-ordinated control of STATCOM AC and DC voltage so as to overcome a potential negative interaction. A comprehensive demonstration is presented by an example power system installed with a STATCOM View full abstract»

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  • A study of transmission planning under a deregulated environment in power system

    Page(s): 649 - 654
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    Under a deregulated environment, power system operators such as utilities have to expand and reinforce the transmission network so that all participants can utilize the network equally and fairly. However, it is difficult for the power system operators to forecast how often the network will be utilized or which bus the users will connect to. Therefore, more uncertain factors exist in the transmission planning problem under a deregulated environment. This paper presents a method for evaluating the maximum power which can be injected to a bus and identifying some transmission lines which result in the bottleneck under the uncertain conditions. This paper also investigates a probabilistic load flow to consider the statistic characteristics of load change and line fault occurrence View full abstract»

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