Economic impacts of power electronics on electricity distribution systems Carlos Henrique Duarte * , Roberto Schaeffer Energy Planning Program – Federal University of Rio de Janeiro (PPE/COPPE/UFRJ), Av. Horácio Macedo, 2030, CT, C-211, Cidade Universitária - Ilha do Fundão, Rio de Janeiro, RJ 21941-972, Brazil article info Article history: Received 22 October 2009 Received in revised form 19 February 2010 Accepted 21 March 2010 Available online 31 July 2010 Keywords: Electricity consumption Energy efficiency Harmonic distortion abstract To achieve more efficient energy use, power electronics (PEs) may be employed. However, these intro- duce nonlinear loads (NLLs) into the system by generating undesired frequencies that are harmonic in relation to (multiples of) the fundamental frequency (60 Hz in Brazil). Consequently, devices using PEs are more efficient but also contribute significantly to degradation of power quality. Besides this, both the conventional rules on design and operation of power systems and the usual premises followed in energy efficiency programs (without mentioning the electricity consumed by the devices themselves) consider the sinusoidal voltage and current waveforms at the fixed fundamental frequency of the power grid. Thus, analysis of electricity consumption reductions in energy efficiency programs that include the use of PEs considers the reduction of kWh to the final consumer but not the additional losses caused by the increase in harmonic distortion. This article contributes to a better understanding of this problem by reporting the results of a case study of the ownership and use of television sets (TV sets) to estimate the economic impacts of residential PEs on a mainly residential electricity distribution system. Ó 2010 Published by Elsevier Ltd. 1. Introduction Many articles address the impacts of the harmonic distortions caused by devices equipped with PEs [1e 16]. Some works have focused on the relationship between their applications and elec- tricity consumption [7,16,17], but few have quantified the economic impacts from the standpoint of single-phase electrical loads in typically residential distribution systems [6,18]. Moreover, we did not find any estimate in the literature of the economic impacts of the various components of low-voltage power distribution systems from the harmonic distortions caused by loads from PEs over a long period, relying on data on the ownership and use of appliances equipped with PEs. In general, energy efficiency programs in Brazil, that are a low- cost alternative compared to additional generation capacity, focus mainly on enhanced efficiencies in kWh saved to the final consumer because of the application of PEs, but do not take into account their contribution to additional losses caused by increased harmonic distortions of voltages and currents in power grids. Besides this, measurement of electricity consumed occurs under the assumption of a sinusoidal waveform at a fundamental frequency of 60 Hz. Thus, harmonics directly affect utility companies’ costs and revenues and this aspect has largely been ignored by energy efficiency specialists [1]. Since such information is highly relevant for planning and regulation of electricity systems, in this paper we use data on TV sets use from two surveys on the ownership and use of electrical appliances (called Pesquisas de Posse e de Hábitos de Uso, or PPHs), carried out in a Brazilian state responsible for about 12% of Brazil’s total electricity consumption, to estimate the economic effects of the harmonics generated by TV sets on the distribution system. 2. Geral View of Power Electronics and Power Quality Advances in semiconductor device technology have led to great improvement of microelectronics device manufacturing processes. The use of integrated circuits and/or digital signal processors has improved control over both voltages and electrical currents, aside from increasing this device’s switching operation at high frequen- cies. Thus, PEs operate at high frequencies, up to hundreds of kHz, allowing electrical devices to be smaller in weight and size and to dissipate heat better in comparison with other components oper- ating at low frequencies. This allows more efficient final use of electricity [2]. However, PEs are more sensitive to oscillations lasting milliseconds in the power source and behave as NLLs, which can cut the current into apparently arbitrary waveforms, causing it to deviate from its normal sinusoidal form, hence generating harmonic frequencies (120 Hz, 180 Hz, 240 Hz, .). * Corresponding author. Tel.: þ55 21 2562 8761/8769; fax: þ55 21 2562 8777. E-mail addresses: chduarte@ppe.ufrj.br, chdqee@gmail.com (C.H. Duarte), roberto@ppe.ufrj.br (R. Schaeffer). Contents lists available at ScienceDirect Energy journal homepage: www.elsevier.com/locate/energy 0360-5442/$ e see front matter Ó 2010 Published by Elsevier Ltd. doi:10.1016/j.energy.2010.03.037 Energy 35 (2010) 4010e4015