power quality compensation using universal power quality conditioning system

generic loads,” IEEE Trans. Power Delivery , vol. 8, no. 2, pp. 697-703, Apr. 1993. Copyright Statement: ISSN 0282-1724/00/$10.00 2000 IEEE. Man uscript received 28 Apr il 2000. Thispaper is publis hed her einin its entirety. Power Quality Compensation Using Universal Power Quality Conditioning System Dušan Graovac, Vladimir Katic, Alfred Rufer Author Affiliation: Institute for Power, Electronics and Telecom- munications Engineering, Faculty of Engineering, University of Novi Sad, Novi Sad, Yugoslavia. Abstract: The ai m of this le tte r is to pr es ent a uni ve rs al powe r qua l- ity conditioning system (UPQS) named after unified power quality conditioner (UPQC), which is extended by adding a shunt active filter at the load side. Its main purpose is to compensate for supply voltage and load current imperfections, such as sags, swells, interruptions, im- balance, flicker, harmonics, reactive currents, and current unbalance. Converter and control analysis is presented together with results show- ing the UPQS modes of operation. Introduction: Power electronics loads inject harmonic currents in the ac system and increase overall reactive power demanded by the equiv ale nt load. On the other hand, de vel opment in the digital ele ctron- ics/communications and in process control have increased the number of sensitive loads that require ideal sinusoidal supply voltages for their proper operation [1]. The load/supply and supply/load influence is listed in Figure 1. In order for power quality to meet limits proposed by sta ndards it is nec essaryto includ e some sor t of compensat ion. Modern sol uti ons for active po wer fa ctor correction can be foun d [2]in forms of active rectification (active wave shaping) or active filtering. Such solutions are suited for elimination of negative load influence to the supply network. If there are supply voltage imperfections, none of them can provide proper compensation. In last fe w yea rs solutions based on fle x- ible ac transmission systems (FA CTS) have appeared. FACTS convert- ers have been modified to serve in distribution networks and through a mod if ica tion of a unif ied pow er flo w controlle r (UP FC) . Uni fied po wer quality conditioners (UPQC) were presented during 1998 [3]. Topology of UPQS: As known, elimination of supply voltage im- perfe ctions can be done using a serie s filt er [4]. Also, the series filter can compensate load current harmonics in the case of voltage-type harmonic producing loads (capacitively loaded diode rectifier). If such a solution is implemented, voltage regulation demands dc bus capacitor cha rgi ng. If a diode rec tif ier is used for cha rging, the n only vol tage sags can be compensated.If a vol tage swell compensat ion is desired, the n an active rectifier should be used, leading to solution known as UPQC [5]. 58 0272-1724/00/$10.00©2000 IEEE IEEE Power Engineering Review, December 2000 2001 Cigré International Symposium on Gas and Electricity Networks: Complementarity or Competition 3-6 December 2001, Iguaçu, Brazil Cigré and the International Gas Union (IGU), in cooperation wit h the Bra zil ian Nat iona l Committ ee of Cigr é, Cigr é Stu dy Com- mittee (SC) 37 on Power System Planning and Development, SC 38 on Power System Analysis and Techniques, and SC 39 on Power System Operation and Control are organizing an Interna - tional Symposium on Gas and Electricity Networks: Comple- mentarity or Competition. The conference will take place in Iguaçu, Brazil, 3-6 December 2001. The electricity supply industry in each country has to adapt it- self to a rapidly changing world: new institutional arrangements are evolving almost everywhere, concern about the impact of its acti viti es on the envi ronment is incr easi ng, and technical changes are taking place at a fast pace. The gas supply industry is also undergoing dramatic changes with a very high growth in deman d andthe openi ng of mar ket s. Wi th the inc reasein theuse of gas for power generation and the growing number of compa- nies offering services in both the gas and electricity fields, the questio n of complemen tarity and competition between gas and elec tri city net wor ks coul d shap e the futu re of ener gy comp anie s. The objectives of the symposium are to: q Gather information in order to establish the current state of the art on the following topics: comparison of gas utiliza- tion for producing electric energy with other types of pri- mary energy; optimal location of the generating units using gas (co mparison bet ween gas transport and elec tri city transmission); comparison between large units and decen - tralized solutions, taking into account generation technolo- gies as well as gas and electricity networks; and coopera tion between gas and power utiliti es. q Outline the per spe cti ves fro m thenext 10-20 yea rs con cer ning the development of gas and electricity trans mission networks. T echnical, organizational, economic, and regulatory matters will be consider ed. The conference is directed towards managers, technical people, and financial experts who are involved in electricity generation and tra nsmission, as wel l as gas production and tra nsp ort ati on. Par tic i- pants may be involved in planning the construction of new plants, managing ass ets or operating fac ilities in the energy market. Par tic - ipa tio n of members fro m regula tor y agencies is for ese en along with managers from national and international organizations involved in energy policy and planning. A large participation of new and pro - spective investors in the power sector is awaited. Registration for ms and the symposiumpro gra m wil l be sent out by the Cigré National Commit tee s in June 2001. All cor respondence shouldbe sen t to the symposiumsecretari at, Cig ré,21 rued’Artois, F 75008 Paris, +33 (0)1 53 89 12 90, fax +33 (0)1 53 89 12 99, e-mail [email protected] or [email protected]. Figure 1. Power quality issues in a typical industrial installation Figure 2. UPQS

power quality compensation using universal power quality conditioning system

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