tap may be requested to change positions multiple times each day, without interrupting the power delivery, to follow loading conditions on the low-voltage (secondary winding) network. To minimize the number of winding taps and thus reduce the physical size of a tap changing transformer, a 'reversing' tap changer winding may be used, which is a portion of the main winding able to be connected in its opposite direction (buck) and thus oppose the voltage. Standards considering tap changers Further reading References Old References (To Do: Integrate Citations) Raka Levi, “CONDITION ASSESSMENT OF OLTCs”, Minutes of the WECC substation working group meeting, Salt Lake City, UT, May 2014 <http://www.dii.unipd.it/~pesavento/download/ISH2009/Papers/Paper-D-16.pdf> G. Andersson, R. Levi, E. Osmanbasic, “Dynamic tap changer testing, reactors and reactance”, CIRED, 22nd International Conference on Electricity Distribution Stockholm, June 2013, Paper 0338. <http://www.cired.net/publications/cired2013/pdfs/CIRED2013_0338_final.pdf> Eric Back, Marcos Ferreira, Dave Hanson, Edis Osmanbasic, “TDA: Tap-changer Dual Assessment”, TechCon USA, Chicago, paper D12, 2012 R. Levi, B. Milovic, “OLTC dynamic testing”, Proceedings TechCon USA, San Francisco 2011. <http://progusa.net/DV-Power/pdf/NOV2011/OLTC_Dynamic_Testing_P10.pdf> Electric transformers