Uma contribuição à avaliação de desempenho dos principais métodos para a modelagem de cargas nos estudos do compartilhamento das responsabilidades sobre as distorções harmônicas

Abstract

Amongst a variety of subjects covered by the area of the Power Quality the harmonic distortion matters emerge as questions of major importance. The relevance of such topic has motivated regulating agencies, concessionaires, consumers and researches to deal with the challenges associated to the area. As a matter of fact, these concerns are growing in relevance as far as the disturbance loads are increasing in number and power. Considering the site effects that voltage distortion may cause in both the utility and consumer, international and national organizations are looking forward to the establishment of standards to limit the level of distortion found in real systems. This is the case of the guide lines provided by the ONS and ANEEL agencies. Although the existence of national and international references, in a general way, they focus the definition of recommended values to the total and individual harmonics, without worrying about their origin. Therefore, for a given situation, if the limits are overcome, the cost of mitigation techniques became a great problem to be sorted out, mainly due to the high cost of investment necessary to the implementation of filters and others. In order to achieve a fairer way to split the responsibility between the agents, methods to indicate the degree of responsibility upon the measured harmonic voltage distortion at a PCC must be investigated. Within this context appears the concept of "total harmonic voltage sharing of responsibility". This is the main target of this dissertation, which aims to summarize the state of the art of the theme, with emphasis to the use of the superposition method. In addition to the basic principles, the work also points out the main difficulties linked with its use of this approach and, in particular, investigates the main procedures related to the characterization of the equivalent harmonic load impedance as well as the supply one. Existing methods are highlighted to deal with the consumer equivalent impedance and computational tests are made and discussed so as to find their advantages and disadvantages in finding the correct harmonic responsibility between the power supply authority and the consumer.