Made available in DSpace on 2014-06-11T19:30:51Z (GMT). No. of bitstreams: 0 Previous issue date: 2012-04-05Bitstream added on 2014-06-13T20:21:18Z : No. of bitstreams: 1 moura_rf_dr_ilha.pdf: 1254278 bytes, checksum: 677c70fd86312d242054dec150169d11 (MD5) / Outros / Este trabalho trata da análise da estabilidade a pequenas perturbações de sistemas elétricos de potência multimáquinas considerando a atuação de Estabilizadores de Sistemas de Potência (ESPs) e de controladores do tipo Power Oscillation Damping acoplados a dispositivos FACTS UPFC (conjunto UPFC/POD). Um de seus objetivos é analisar como o posicionamento dos zeros da função de transferência em malha aberta (FTMA) do sistema elétrico de potência influencia na localização e na capacidade dos controladores em introduzir amortecimento às oscilações de baixa frequência. De maneira usual, uma análise de sensibilidade, através do método dos resíduos fornece a localização para instalação do conjunto UPFC/POD e/ou ESP. Entretanto, será mostrado neste trabalho que a quantidade de amortecimento fornecido ao modo eletromecânico de interesse utilizando os controladores suplementares de amortecimento é limitada pelo zero da FTMA do controlador. Desta forma, o ESP ou o conjunto UPFC/POD instalado na melhor localização obtida através do método dos resíduos pode não fornecer o coeficiente de amortecimento desejado ao polo de interesse. Outro objetivo é o ajuste dos parâmetros destes controladores e são utilizadas duas técnicas, sendo uma baseada na compensação de fase e chamada de método dos resíduos. Também é proposta outra forma de ajuste, fundamentada em algoritmos genéticos. Para a execução desses estudos o Modelo de Sensibilidade de Potência é utilizado para a representação do sistema elétrico de potência. Resultados são apresentados para dois sistemas teste: sistema simétrico com 4 geradores, 10 barras e 9 linhas de transmissão e o sistema New England com 10 geradores, 39 barras e 46 linhas de transmissão / This work deals with the small-signal stability analysis of multimachine power systems considering the Power System Stabilizers (PSS) and Power Oscillation Damping (POD) performance. POD is coupled to the FACTS (Flexible Alternating Current Transmission Systems) UPFC (Unified Power Flow Controller). An analysis of the open-loop transfer function (OLTF) zeros of the electric power systems is carried out aiming to verify the influence of the OLTF zeros placement on the controllers location and ability to introduce damping to low frequency oscillations. In the usual way, a sensitivity analysis, using the residue method, provides the UPFC/POD and/or PSS location. However, will be shown in this work that the damping provided to interest eigenvalue using a supplementary damping controller is limited by the OLTF zeros placement. Thus, the PSS or the UPFC/POD installed in the best location obtained by the residue method cannot provide the desired damping coefficient to the interest pole. Another objective of this work is to evalmate the performance of the controller parameters tuning. Two techniques are used with this objetive. One of then is based on phase compensation and called the residue method. The second one is based on genetic algorithm method. For the execution of these studies the Power Sensitivity Model (PSM) is used to represent the electric power system. Results are presented for two test systems: a test system with 4 generators, 10 buses and 9 transmission lines and the New England System that has 10 generators, 39 buses and 46 transmission lines

Eskom is experiencing problems in the field of protection maintenance and in-service breakdowns which negatively influence the quality of electrical supply to the consumer, an integral component of the utility business. These facts initiated the research into the further development of a generic relay to be implemented as a strategic spare for the replacement of several schemes operating within Eskom’s southern region. These include the electromechanical, solid state and numerical distance protection relay and scheme failures on the 132 / 66 kV feeder network. Hence, the primary objective of the research is to develop, test and configure the strategic spare in terms of software and peripheral hardware for the input and output terminal connections, generic equations and settings for the purpose of the scheme replacements. The various schemes are assessed for stepped distance and permissive intertripping for three or single pole operation. This is done in conjunction with the internal and external circuit diagrams in order to understand the detailed operation of the scheme and to ensure the effective implementation of the strategic spare. The generic relay is configured for the emergency replacement of the various schemes during in-service breakdowns. This constitutes a temporary installation and therefore the downtime in essence, of all the distance protection schemes that require replacement, is limited to a minimum. This dissertation therefore explores the implementation of the strategic spare.

In this thesis models for the simulation of transient phenomena in high voltage direct-current systems are developed. The new converter model is versatile and the solution algorithm is free from numerical oscillations. A new generic inverter control described in this thesis is based on a predictive approach. Steady-state and transient simulations of two-terminal and multi-terminal (i.e., a parallel converter system) high voltage direct-current systems are carried out using the new converter system model. Comparison between the two-terminal transient simulation results and the high voltage direct-current simulator outputs shows good agreement. An alternating-current/direct-current initialization procedure for the Electromagnetic Transients Program (EMTP) has been investigated and a novel initialization algorithm has been suggested in this thesis. / Applied Science, Faculty of / Electrical and Computer Engineering, Department of / Graduate

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

The successful application of HVDC transmission links requires correct predictions of the performance of the dc link and the ac system to which it is interconnected. Whatever the system configuration, the steady-state, dynamic and transient behaviour of the associated dc and ac systems are mostly interdependent. To simulate these phenomena with digital computers, converter stations must be modelled in more detail than as simple dc sources. This thesis discusses the development and implementation of a converter model which enables the converter bridge circuits to be represented in detail and the valve ignition to be controlled in the constant current mode. The model has been added to the U.B.C. Electromagnetic Transients Program to permit simulations of the complete ac/dc system. It is used to analyze the harmonics during steady-state operation, and to compare the results with those obtained from conventional (approximate) formulae. In a transient case, the new model gives closer agreement with field measurements than the simplified model used before. / Applied Science, Faculty of / Electrical and Computer Engineering, Department of / Graduate

A research project submitted to the Faculty of Engineering and the Built Environment, University of the Witwatersrand, in fulfillment of the requirements for the degree of Master of Science in Engineering, 2018. / The power system inertia immediately following small and large system disturbances was investigated. By understanding factors affecting the system inertia and primary frequency response behaviour, an online inertia model was developed. Historical data was extracted from the Eskom Energy Management System (EMS) and Wide Area Monitoring System (WAMS). The developed model using Multivariate Analysis (MVA) includes measured and estimated data from Eskom generators, Renewable Energy Sources (RESs) and the interconnected Southern African Power Pool (SAPP). Inertia plus Fast Primary (Frequency) Response (FPR) (as determined by the load behaviour) and system inertia models were developed from June 2015-December 2016 and validated with past frequency disturbance events (June 2014-March 2017). From the comparison between the measured and model results for 355 actual disturbances, 225 disturbances resulted in errors within ±5% and 51 events resulted in errors between ±5% and ±10%. Eight disturbances caused errors greater than ±10%, which were largely from trips at particular large power stations and HVDC. During a large disturbance, the multivariate coefficients for Renewable Energy Sources, HVDC and interconnectors were very small for the pure inertia model (excluding the load frequency behaviour and the generator damping). In contrast, the spinning reserve provides significant contribution and is location based. The location of a disturbance affects the FPR behaviour and the system inertia but not the Rate of Change of Frequency (RoCoF) with reference to the central power station. The strong and weak areas with respect of the stiffness of the system (extent of frequency nadir for particular disturbances) were identified. This can contribute to future grid planning and real-time operations in managing the system inertia and primary frequency response. The model is expected to improve with time, as the accuracy of a statistical approach requires large amounts of data. The model can be used to determine and monitor the maximum level of RES in real time. / XL2019

No description available.

No description available.

No description available.

No description available.