Performance of high voltage transducers for measurement of power quality disturbances – modeling and simulation HÉDIO TATIZAWA 1 , ERASMO SILVEIRA NETO 2 , GERALDO F. BURANI 1 , ANTÔNIO A. C. ARRUDA 1 , KLEIBER T. SOLETTO 1 , NELSON M. MATSUO 1 2 Companhia de Transmissão de Energia Elétrica Paulista – ISA CTEEP 1 Instituto de Eletrotécnica e Energia da USP – IEE/USP Av. Prof. Luciano Gualberto, 1289 – São Paulo BRAZIL hedio@iee.usp.br http://www.iee.usp.br Abstract: - In order of to keep under control power quality parameters in transmission and distribution networks, reliable measurements are necessary to assure the conformity with standards or other national or international regulatory documents [1]. For these measurements, the use of high voltage transducers is imperative for to provide a low voltage signal, for instance, under 1000V, considering that power quality analyzers in general can measure only low voltage signals. As power quality technical standards, not yet, cover calibration procedures for high voltage transducers, necessary to assure reliability for such measurements, this research proposes possible experimental setup for such calibrations, in real high voltage transducers. Key-Words: - high voltage transducers, capacitive voltage dividers, power quality measurements, harmonics, IEC 61000 series, high voltage 1 Introduction The increase of sensitive loads in electrical networks, and increase in the harmonic content in voltage and in electrical current, is a reality today [2, 3, 4, 5, 6, 7]. Most of the sensitive loads, producing distorted current and at the same time, more prone to be affected by those harmonics, are connected to the low voltage network. However, as a matter of fact, harmonics are reflected to the power system high voltage side through power transformer, spreading its effects. In some situations high power distorting loads, for instance, high power arc furnaces, in the range of hundreds MVA, are fed directly by the high voltage network, being necessary to perform measurements of the power quality parameters at high voltage level. Also, others types of power quality disturbance, like voltage sags and swells, may be caused by faults in the high voltage network, causing effects both in the high and low voltage level [8]. The increase of the distributed generation, using power electronics based equipment like power inverters, connected with the transmission and subtransmission grid at high voltage levels, imposes the measurements to be performed at this high voltage level, to assure conformity with regulatory and technical standards [1]. Hence, this research presents some studies on possible experimental setup for such calibrations, in real high voltage transducers, and shows some practical difficulties on this subject. 2 Test Setup The conventional high voltage laboratory, in general, is equipped only with high voltage sources for generating power frequency (60Hz or 50Hz) and impulse (atmospheric and switching) high voltage waveforms, used in dielectric tests of high voltage equipment insulation [9]. For calibration of high voltage transducers used in measurements of power quality disturbances, additional waveforms are necessary, for instance, voltage harmonics, sags (or dips), swells, etc. In this way, in this research, the following test circuit components were defined, in order to achieve the calibration circuit: - arbitrary waveform voltage source for generating sinusoidal waveforms, with low harmonic distortion, considering harmonic frequencies up to the 50th order (3000Hz), and generation of composite waveforms (fundamental frequency + harmonics), with enough power capacity for the calibration tests. In this research, a conventional commercial power quality generator was used for this purpose. - a step-up high voltage test transformer, fed at the low voltage side by the arbitrary waveform voltage source, to produce in the high voltage side, the waveforms generated by the source (considering composite waveforms and harmonics), with enough power required by the calibration tests. The option of to generate high voltage waveforms in the way described above, was motivated by absence, or by the non availability, of high voltage sources for the Proceedings of the 10th WSEAS International Conference on AUTOMATION & INFORMATION ISSN: 1790-5117 275 ISBN: 978-960-474-064-2