Comparison of Derating in Transformerunder Non-Linear Load and Imbalanced Supply Voltage Based on Tsfem

Yıl 2020, Cilt: 8 Sayı: 2, 336 - 353, 03.06.2020

Atabak Najafı

https://doi.org/10.36306/konjes.576552

Öz

Distribution transformers which are widely used in industry and distribution centers are the
most affected by voltage imbalance and harmonic loads. These situations have a negative impact on
efficiency , core loss and winding loss of distribution transformers, In this article, derating as well as losses
increase of transformer under non-linear loads and imbalanced supply voltage conditions are examined .
harmonic loss factor (HFL) and K-factor have been used to perform the transformer derating. In this study,
3D time-step finite element method(TSFEM) used to observe the magnetic flux density formed in the
windings and core of the distribution transformer. According to the results obtained, it is seen that the
IEEE standard is insufficient for the derating of the transformer under high harmonic current (THDI) and
unbalanced conditions and Time Stepping Finite Element Method is a more suitable method.

Anahtar Kelimeler

derating, TSFEM, harmonic load, unbalanced voltage

ZASEY’E DAYALI HARMONİKLİ YÜK VE DENGESİZ BESLEME GERİLİMİ ALTINDA TRANSFORMATÖRÜN İNDİRGENMESİNİN KARŞILAŞTIRILMASI

Öz

Endüstri ve dağıtım merkezlerinde yaygın olarak kullanılan dağıtım trafoları, gerilim
dengesizliğinden ve harmonik yüklerden en fazla etkilenen elektrik makinalarıdır. Bu durumlar dağıtım
trafoların verimini, nüve kaybı ve bakır kaybı gibi parametreleri üzerinde olumsuz etkisi vardır. Bu
makalede, harmonikli yükler ve dengesiz besleme gerilimi koşulları altında Dağıtım Trafosunun
İndirgenmesi ve kayıplardaki artış incelenmiştir. Transformatörün indirgemesini gerçekleştirmek için kfaktörü
ve harmonik kayıp faktörü (HFL) kullanılmıştır. Bu çalışmada dağıtım transformatörünün
sargılarında ve çekirdeğinde oluşan manyetik akı yoğunluğunu gözlemlemek için üç boyutlu zaman
adımlı sonlu elemanlar yönteminden (ZASEY) faydalanılmıştır. Elde edilen sonuçlara göre IEEE
standardının yüksek harmonikli akım (THDI) ve dengesiz koşulları altında transformatörün indirgenmesi
için yetersiz, ZASEY’nin ise daha uygun doğru bir yöntem olduğu görülmüştür.

Anahtar Kelimeler

İndirgeme, ZASEY, harmonik yük, dengesiz gerilim

Kaynakça

• A. Emadi , Y. J. Lee , K. Rajashekara “Power Electronics and Motor Drives in Electric, Hybrid Electric, and Plug-In Hybrid Electric Vehicles” IEEE Transactions on Industrial Electronics , Volume: 55 , Issue: 6 , Page(s): 2237 - 2245 ,June 2008 .
• O. P. Taiwo , R. Tiako, I. E. Davidson “Voltage Unbalance Mitigation and Voltage Profile Enhancement in Secondary Distribution System Using Dynamic Voltage Restorer” International Journal of Engineering Research in africa ,Volume 34,pages : 81-101, 2018.
• A. Najafi, I.Iskender, N. Genc, “ Evaluating and Derating of Three-Phase Distribution Transformer Under Unbalanced Voltage and Unbalance Load Using Finite Element Method “ IEEE 8th International Power Engineering and Optimization Conference ,PEOC0-2014.
• S.Taheri,A. Gholami, I. Fofana, H. Taheri “Modeling and simulation of transformer loading capability and hot spot temperature under harmonic conditions” Electric Power Systems Research, Volume 86, Pages 68-75, May 2012.
• O. E. Gouda , G. M .Amer,., “A Study ofK- Factor Power Transformer Characteristics by Modeling Simulation, ETASR-Engineering, Technology & Applied Science Research,114-120, Vol. 1, no. 5. 2011.
• J. Faiz , M.Ghazizadeh, H. Oraee “Derating of transformers under non- linear load current and nonsinusoidal voltage–an overview” IET Electric Power Applications ,Volume 9, Issue 7, p. 486 – 495, 2015.
• M.A. Taghikhani , M. Rafiei “Thermal coefficient measurements of typical distribution transformers operating under imbalance conditions, 16th Electrical Power Distribution Conference, 2011.
• S. Bhushan , K.Asheesh,P.Thakur“Assessment of induction motor performance under voltage unbalance condition’’IEEE 15th International Conference on Harmonics and Quality of Power, Hong Kong, 2012.
• N.R. Patne 1 and K.L. Thakre 1’ Effect of transformer type on estimation of financial loss due to voltage sag- PSCAD/EMTDC simulation study” IET Generation, Transmission & Distribution , Volume 4, Issue 1, pages:104-114,2010.
• Hyun-Mo Ahn , Ji-Yeon Lee , Joong-Kyoung Kim ”Finite-element analysis of short-circuit electromagnetic force in power transformer” IEEE Transactions on Industry Applications ( Volume: 47 , Issue: 3 , Page(s): 1267 – 1272, May-June 2011 .
• E. Rahmat “Analisa Pengaruh Harmonisa Terhadap Faktor-K Pada Transformator”SP - Electrical Engineering’ http://respository.usu.ac.id/handle , 2013.