DETERMINATION OF VOLTAGE CONFORMITY FACTOR IN POWER SUPPLY SYSTEMS

2019;
: pp. 64-72
1
Lviv National Agrarian University
2
Lviv Polytechnic National University, Ukraine
3
Krakow University of Technology, Poland

New  technical  developments,  such  as  in  the  field  of  frequency  drives  of  technological  units,  electrified transport, wind, and solar power plants, apply devices built on the basis of powerful transistors. Modern devices designed on these elements  are  powerful  generators  of  higher  harmonics  of  currents  that  penetrate  the  grids  of  power  systems.  It  requires  the development of measures and means to limit the higher harmonics of currents in the electrical grids. 

The method and the means of determining the voltage distortion coefficient by higher harmonics in electric networks are considered in the paper. This factor belongs to the group of main indicators of electricity quality, which are regulated by national standards and international standards for electricity quality. The shortcomings in the existing methods are pointed out and a method is proposed which allows  increasing  the accuracy of  the specified  indicator significantly. Based on  the actual measurement and using certified equipment, it is shown that the error of the measurement results and their calculation by using the proposed method does not exceed 1 % of the nominal voltage, while the existing norms of this factor, depending on the voltage of the power supply system,  regulate value of error  from 2 % to 8 %. Considering  that  the commonly used measuring equipment does not  take into account the interharmonics and exponential components in the supply voltage, the proposed method regarding these components over a predetermined time interval, much larger than one period, provides higher accuracy for determining the distortion factor. By examining  all  harmonics  and  interharmonics,  including  zero  and  exponential  components,  we  provide  substantially  higher accuracy than the existing methods described in the standards and norms for electricity quality. 

[1]  I. Zhezhelenko, Yu. Sayenko. Indicators of Quality of  Electric  Energy  and  Their  Determination  in  Industry. Moscow, RF: Energoatomizdat, 2000.  

[2] Polska norma PN-EN 61000-3-11. Kompatybilność elektromagnetyczna (EMC) Część 3–2: Poziomy  dopuszczalne emisji  harmonicznych  prądu  (fazowy  prąd  zasiłający odbiornika  16 £ , 2004.

[3] Polska Norma PN-EN 50160.  Parametry napięcia zasiłającego  w  publicznych  sieciach  elektroenergetycznych, 2010.

[4] Norma  Europejska  EN  610000  –  4–7  z włączona poprawką  AC1:2004  ma  status  Polskiej  Normy. Kompatybilność  elektromagnetyczna  (EMC)  Część  4–7: Metody  badań  i  pomiarów.  Ogólny  przewodnik  dotyczący pomiarów harmonicznych  i  interharmonicznych  oraz  przyrządów  pomiarowych,  dla  sieci  zasiłających  i  przyłączonych  do nich urządzeń, Warszawa, Polska 2007.

[5] M. Marz,  Interharmonics: What  They Are, Where They  Come  From  and  What  They  Do.  [Online].  Available: https://ccaps.umn.edu/documents/CPE-Conferences/MIPSYCON-Papers/2016/Int...

[6]  J.  Arrillaga  and  N.  R.  Watson,  Power  System Harmonics, John Wiley & Sons, Ltd, 2003.

https://doi.org/10.1002/0470871229

[7] R. Polikar, The Wavelet Tutorial. Part I. Fundamental Concepts & an Overview on  the Wavelet Theory.  [Online]. Available: http://web.iitd.ac.in/~sumeet/WaveletTutorial.pdf.

[8]  P.  Wojtaszczyk,  A  Mathematical  Introduсtion  to wavelets.  Cambridge  CB2  IRP, United Kingdom:  Cambridge University Press. 1997.

[9] Amara Graps, An Introduction to Wavelets. Institute of  Electrical  and  Electronics  Engineers,  Inc.,  1995 https://www.eecis.udel.edu/~amer/CISC651/IEEEwavelet.pdf

[10]  V.  Hudym,  “Technical Means  for  Lowering  the Harmonics Power in Electric Power Supply Systems, Technical Eletrodynamics, No 3, cc.67-72, 1996

[11].  V.  Hudym,  V.  Kosovska, A.  Drval,  V.  Chuhra, “Method  for  determining  harmonic  coefficients  and  voltage deviation  in  single-phase  electrical  networks”.  Pat.  UA  for utility model No 132863, Bull. 5, 2019. 

[12].  U. Ashimov,  D.  Satvaldiev, Yu.  Chernov,  “Six-electrode  unit  of  ore  thermal  furnace  with  round  bath”,  A.S. USSR 1702544, Bull. 48a, 1991.