Efeitos das distorções harmônicas (tensões e correntes) e desequilíbrios (tensões) em medidores eletrônicos trifásicos de energia elétrica ativa
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Data
2008-11-17
Autores
Silva, Luiz Carlos Evangelista da [UNESP]
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
Considerando-se as constantes mudanças que vêm ocorrendo no cenário de distribuição de energia elétrica, devido ao grande avanço da eletrônica de potência e cargas não lineares instaladas no sistema elétrico, fazem-se necessários estudos para diagnosticar como e quanto essas alterações interferem nos equipamentos instalados nas redes de distribuição. A proposta desta dissertação é a análise da influência das distorções harmônicas (tensões e correntes) e desequilíbrios (tensões) nos erros de medição de energia elétrica ativa em medidores eletrônicos trifásicos. Estes equipamentos são normalmente projetados para atuarem com condições ideais de freqüência constante, formas de onda de tensão e corrente senoidais e em sistemas equilibrados. Condições estas, que não refletem a realidade das redes de distribuição de energia elétrica. Para a realização da análise dos equipamentos selecionados, submetidos aos efeitos das componentes harmônicas nas tensões e correntes, inclusive desequilíbrios de tensões, montou-se um arranjo padrão de medição, onde foram ensaiados os medidores submetidos a estes distúrbios, sob as mesmas condições laboratoriais, considerando-se três repetições para cada amostra selecionada. As distorções harmônicas de tensões e correntes, aplicadas nos ensaios, foram obtidas por medições em consumidores em ramais de distribuição com características industrial, comercial, rural e residencial, e, os desequilíbrios de tensões admitidos para ensaios foram de 3% (limite atual) e de 5%, considerando-se determinados cenários de um sistema de distribuição real de uma concessionária de energia elétrica. Os resultados são apresentados em forma de tabelas e figuras, e, as análises dos erros são apresentadas considerando-se um padrão de medição composto por analisador de energia com classe de exatidão...
Considering the constant changes that have been occurring in the electric energy distribution scenery, due to the great improvements of the power electronics devices and non linear loads installed in the system, there are several studies developed in order to analyze and diagnosis the effects of these changes, and how much these loads affect the equipments installed on the distribution systems. The proposal of this research is to analyze the influence the harmonic contents (voltage and current) and unbalances (voltage) in the systems on the measurement errors of the active electric energy using three-phase electronic meters. These equipments are usually designed to operate on ideal conditions with constant frequency, sinusoidal voltage and current waveforms, and balanced system. However, these conditions are not the reality of the electric energy distribution systems. The procedures for the measurements, considering the selected samples of the electronics meters under influence of current and voltage harmonic contents, and voltage unbalances, were based on a measurement set-up established for testing, in the same conditions, all the selected samples considering its three repetitions. The harmonic voltage and current contents, applied in the tests, were obtained by measurements in consumers with different load characteristics (industrial, commercial, rural and residential), and the admitted voltage unbalances were of 3% (actual limit imposed by standards) and 5%, considering real cases of an electric energy distribution system of an utilities. The results are summarized in tables and figures, and the analyses of the errors are presented considering comparisons with a standard of measurement composed by an energy analyzer, with accuracy of 0.1% for voltages and currents, and, 0.2% for active power, considering the range of 60Hz until 1kHz. In addition, models were developed... (Complete abstract click electronic access below)
Considering the constant changes that have been occurring in the electric energy distribution scenery, due to the great improvements of the power electronics devices and non linear loads installed in the system, there are several studies developed in order to analyze and diagnosis the effects of these changes, and how much these loads affect the equipments installed on the distribution systems. The proposal of this research is to analyze the influence the harmonic contents (voltage and current) and unbalances (voltage) in the systems on the measurement errors of the active electric energy using three-phase electronic meters. These equipments are usually designed to operate on ideal conditions with constant frequency, sinusoidal voltage and current waveforms, and balanced system. However, these conditions are not the reality of the electric energy distribution systems. The procedures for the measurements, considering the selected samples of the electronics meters under influence of current and voltage harmonic contents, and voltage unbalances, were based on a measurement set-up established for testing, in the same conditions, all the selected samples considering its three repetitions. The harmonic voltage and current contents, applied in the tests, were obtained by measurements in consumers with different load characteristics (industrial, commercial, rural and residential), and the admitted voltage unbalances were of 3% (actual limit imposed by standards) and 5%, considering real cases of an electric energy distribution system of an utilities. The results are summarized in tables and figures, and the analyses of the errors are presented considering comparisons with a standard of measurement composed by an energy analyzer, with accuracy of 0.1% for voltages and currents, and, 0.2% for active power, considering the range of 60Hz until 1kHz. In addition, models were developed... (Complete abstract click electronic access below)
Descrição
Palavras-chave
Medidor de watt-hora, Sistemas equilibrados e desequilibrados, Electric energy
Como citar
SILVA, Luiz Carlos Evangelista da. Efeitos das distorções harmônicas (tensões e correntes) e desequilíbrios (tensões) em medidores eletrônicos trifásicos de energia elétrica ativa. 2008. 202 f. Dissertação (mestrado) - Universidade Estadual Paulista, Faculdade de Engenharia de Ilha Solteira, 2008.