No description available.

This thesis describes a method for determining weak nodes in power systems which may cause divergence in Newton-Raphson loadflow methods. When divergence occurs in production loadflow programs, information related to the cause of divergence is not available. The "Weak Node Method" of this thesis provides such information by identifying one or more weak nodes. The development of the Weak Node Method required extensive experimentation with the Newton-Raphson method. The behaviour of the vectors and matrices of the Newton-Raphson method during divergence are discussed in an effort to familiarize the reader with observed trends. These trends suggested the techniques which comprise the Weak Node Method. With this method, a "quasi" solution is sought first, and, secondly, three analysis procedures are then used to pinpoint the weak nodes. The method was tested using three test cases which would normally have caused the Newton-Raphson loadflow method to diverge. / Applied Science, Faculty of / Electrical and Computer Engineering, Department of / Graduate

No description available.

No description available.

Thesis (Ph.D.) -- McMaster University, 1998. / Includes bibliographical references (p. 180-186). Also available via World Wide Web.

This thesis demonstrates the utility of computer simulation in the modelling of hydro-electric and thermal plant operations. It focuses on models of selected facilities in the British Columbia Hydro and Power Authority's integrated system. Four different simulation models are developed. Each successive model develops a variation of the basic program to accommodate the different hydro-electric and thermal plant configurations. When more than one energy producing facility is included in a particular simulation, they are operated on a coordinated basis. The purpose of the models is to assess the energy producing capabilities of alternative configurations. Two types of experiments are performed on the models: model configuration and operating coordinating policy. In terms of the hydro-electric facilities, the scope of the models extends from the simulation of river inflows to reservoirs, through the energy generation phase, to the resultant down river flow. Generally, thermal plant operation is a function of reservoir status. The IBM GPSSV computer language is used in the modelling process. By considering the simulation output over the two types of experiments, it is possible to draw conclusions concerning the ability of certain facility configurations to meet specified energy demands. These conclusions can facilitate B.C. Hydro in the management of its integrated system with respect to planning the construction of new facilities and establishing coordinating-operating policies. Additionally, the value of using GPSSV in the modelling process is discussed. / Business, Sauder School of / Graduate

Thesis (M.Sc.)--Memorial University of Newfoundland, 2003. / Bibliography: leaves 124-131. Also available online.

The present thesis, for the most part, is concerned with the application of continuous optimization to the secure-economic dispatching of thermal power plants. / The general concept of the continuous simulation of the optimum operation of power systems is introduced. This is the characterization of the solution trajectory of the underlying dispatching model as the loads vary along a forecasted trajectory, or as the system parameters continuously change. An efficient continuation algorithm is developed which characterizes the solution trajectory of a secure-economic dispatch model, given a piecewise linear trajectory of the bus loads, parameterized in terms of the system load. The algorithm considers piecewise quadratic generation cost functions, a DC load flow model, and the limits on generations and power flows in the normal and post transmission line outage states. The solution trajectory is provided in an analytic form over the entire loadability range of the system. Applications of the algorithms to systems with up to 118 buses show that it is fast, reliable, and well-suited for many applications in power system planning and operation. / The continuation algorithm, as the thesis describes, in essence applies the Incremental Loading procedure to the secure-economic dispatching. In this light, it can be viewed as a natural extension of the highly successful classical dispatching techniques such as Lambda Dispatching. A reexamination of the classical economic dispatching is presented early in the thesis. Highlights of this phase of the study include: generation scheduling with general (i.e., possibly non-convex) generation cost functions, an analytic study of the Valve Point Loading based on the general characterization of the valve loop based system incremental cost curve, an in-depth study of the system incremental cost in the context of the modified coordination equations, and a stochastic formulation and analysis of economic dispatching of regulating plants.

Orientador: Leonardo Nepomuceno / Co-orientadora: Edilaine Martins Soler / Banca: Andre Christovão Pio Martins / Banca: Eduardo Nobuhiro Asada / Resumo: Este trabalho propõe um modelo de Procedimento de Equilíbrio de Mercado com Restrições de Segurança Estocásticas (PEMRSE) que pode ser utilizado como um modelo de leilão de energia e reserva do dia seguinte por operadores de sistemas hidrotérmicos. O modelo de PEMRSE tem o objetivo de minimizar o custo esperado da operação, considerando os custos associados aos excedentes de geração e consumo, partidas, contratação de reservas e a penalização econômica associada aos cortes involuntários de carga. O PEMRSE considera vários aspectos que dificultam a resolução de problemas de leilão: i) representação detalhada dos sistemas de geração hidrelétrico e termelétrico; ii) perdas na transmissão; e iii) restrições de segurança pré e pós-contingência. São propostas técnicas de linearização que não demandam o uso de variáveis binárias para a função de produção hidráulica e para as funções de potência e engolimento máximo de geradores hidrelétricos. A estrutura estocástica permite cortes involuntários de carga, isto é, o operador pode optar por não contratar a totalidade das reservas necessárias para cobrir as falhas associadas às contingências, ponderando sua decisão pela probabilidade de ocorrência destas falhas e pelo valor da penalização econômica associada ao corte de carga. Propõe-se também uma técnica para a resolução de modelos de PEMRSE em tempos computacionais menores com relação à sua resolução direta. Simulações em um sistema-teste de três barras e no sistema IEEE de 24 barras ... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: This work proposes a Market Clearing Procedure with Stochastic Security Constraints (MCPSSC) model that can be used as an energy and reserve day-ahead auction model by hydrothermal systems operators. The MCPSSC aims to minimize the expected cost of the operation, considering the costs associated with the generation and consumption surpluses, start-ups, contracting of reserves and the economic penalization associated with involuntary load shedding events. The MCPSSC model considers several aspects that complicate the resolution of auction problems: i) detailed representation of the hydrothermal generating systems; ii) transmission losses; and iii) pre- and post-contingency security constraints. We propose linearization techniques that does not require the use of binary variables for the hydro production function and for the maximum power output and maximum water discharge functions of hydro generators. The stochastic structure allows some load shedding, ie, the operator can choose not to contract the total reserve requirements to cover the failures associated with the contingencies, weighting its decision by the probability of occurrence of these failures and by the value of lost load. We also propose a technique for the resolution of MCPSSC models in lower computational times regarding its direct resolution. Simulations in a three-bus test system and in the IEEE 24-bus system show the efficiency of the model, the linearization techniques and the resolution technique proposed.... (Complete abstract click electronic access below) / Mestre

Orientador: Secundino Soares Filho / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Eletrica e de Computação / Made available in DSpace on 2018-08-13T19:42:40Z (GMT). No. of bitstreams: 1 Toscano_AndreEmilio_M.pdf: 30584461 bytes, checksum: 8f532daf632ae90c9325c899608a0457 (MD5) Previous issue date: 2009 / Resumo: Os modelos de planejamento energético aplicados ao Sistema Interligado Nacional (SIN) devem fornecer um despacho de geração hidrotérmica que atenda ao mercado de energia elétrica brasileiro de forma a assegurar o atendimento das demandas e a minimizar os custos operativos. Devido às características hidrelétricas predominantes no sistema brasileiro, o planejamento visa determinar o despacho hidrelétrico otimizado que minimiza a complementação termelétrica necessária ao atendimento das demandas de energia elétrica do SIN. O modelo de planejamento energético de longo prazo em vigor no sistema elétrico brasileiro é o NEWAVE, um modelo estocástico que representa o sistema através de subsistemas equivalentes de energia e que tem sua solução desagregada a usinas individualizadas por outros modelos, como o DECOMP ou SUISHI-O. O modelo ODIN é a metodologia de planejamento energético desenvolvida na UNICAMP, que trata a estocasticidade das vazões afluentes de forma indireta, por meio de um previsor de vazões e de um otimizador a usinas individualizadas, e que a cada intervalo de planejamento fornece as decisões de despacho hidrotérmico por usina considerando as vazões previstas e a otimização da geração hidráulica do sistema. Este trabalho apresenta a comparação de desempenho entre os modelos de planejamento energético NEWAVE e ODIN na obtenção do despacho hidrotérmico otimizado para o SIN / Abstract: The optimization models applied to hydrothermal scheduling on the Brazilian National Interconnected System (SIN) shall provide the order of hydrothermal generation that meets the Brazilian market of electric energy in a way that the demands of power are attended and the operating costs, minimized. Due to the hydroelectric predominant feature in the Brazilian system, the planning aim to determine the optimal hydroelectric generation that minimizes the thermoelectric supplementation necessary to attend the power demands of Brazilian SIN. The long-term hydrothermal scheduling plan model operating nowadays in the Brazilian electrical system is the NEWAVE, a stochastic model that represents the system by equivalent subsystems of energy, through composite reservoirs, and has its solution decompounded of individualized plants by other models, like the DECOMP and SUISHI-O. The ODIN model is the energy planning methodology developed at UNICAMP that treats indirectly the stochasticity of affluent flows. This is done by means of an inflow predictor and an optimizer for individual plants, thats provide the planning decisions at each interval to order the hydrothermal scheduling considering the provided flow generation for each plant and the optimization of the hydraulic generation of the system. This work presents a comparison of performance between the models of hydrothermal scheduling NEWAVE and ODIN, in their obtainment of optimized hydrothermal scheduling for the Brazilian SIN / Mestrado / Energia Eletrica / Mestre em Engenharia Elétrica