Projeto de filtros passivos para a redução de correntes harmônicas na subestação de 2x300 kVA da estação elevatória de água do Jiqui

Abstract

This work is based in a sanitation industry real case where electrical power quality parameters were diagnosed using electrical quantities meters during the predictive maintenance done in Companhia de Águas e Esgotos do Rio Grande do Norte (CAERN). Divergent harmonic currents were observed against the standard recommendations, caused by the use of inverters for driving the motors. To solve this case, this final work presents passive harmonic filters single tuned to be instaled in parallel with the low voltage cables of each 300 kVA transformers that supplies power to raw water pumping station of Jiqui-CAERN, the main water supplier of Natal-RN. The equipments promote the reduction of harmonic current distortion to be within the tolerated levels to comply with the IEC (International Electrotechnical Commission) 61000-3-4 and IEEE (Institute of Electrical and Electronic Engineers) 519 standards. This study models the entire system, from the concessionary power substation until the final loads located in CAERN, and proposes the computer simulations of installing 5th, 7th, 11st and 13rd order filters isolated and integrated, obtaining the answers to all different applications performed with different quality factors. New harmonic current and voltage for each frequency, as well as the system behavior in the frequency a re evaluated. Series and parallel resonances in tuned filters are observed with the computational tool developed by Centro de Pesquisas de Energia Elétrica (Electric Power Research Center) – CEPEL, HARMZS, version 1.8. For currents and voltages simulationsis used the computational tool SCILAB, version 5.5.1