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Utility Transformer Brokers (UTB) is a supplier of Used, New, Reconditioned, and Rewound oil filled substation and unit substation transformers. UTB keeps a large supply of surplus power transformers in our database that are in stock and ready to ship at a moment’s notice.
Substation Transformers have cover-mounted primary bushings with secondary bushings that can be mounted in the cover, on the side or in front. Substation transformers can also be provided with load tap changers (LTC) that automatically regulate the low side voltage without de-energizing the transformer. They are generally connected directly to overhead utility lines and are used to step-down voltage from high to low.
In small power transformers 5-15 MVA with primary voltages up through 69 kV Class, transformers are typically manufactured with rectangular core & coils and layer windings or circular core & coils with disc and helical windings. Rectangular designs are not typically used in transformer applications over 15 MVA or 69 kV.
Unit Substation Transformers are generally coupled to switchgear or bus duct and are designed for commercial and industrial applications where distribution voltage is stepped down to a usable voltage. Unit subs are typically filled with mineral oil, but can be filled with Envirotemp FR3, Silicone, or Biotemp when used for indoor applications.
Manufacturers of station class transformers include: ABB, Kuhlman, Central Maloney, Siemens, Ferranti Packard, Westinghouse, Allis Chalmers, RTE/ASEA, Uptegraff, McGraw-Edison, Howard, Cooper, GE, Prolec, Waukesha, Virginia, Pennsylvania, WEG, Hyundai, and Delta Star.
Typical base ratings station class transformers are: 500 KVA, 750 KVA, 1000 KVA, 1500 KVA, 2000 KVA, 2.5 MVA, 3 MVA, 3.75 MVA, 5 MVA, 7.5 MVA, 10 MVA, 12 MVA, 15 MVA, 18 MVA, 20 MVA, 24 MVA, 30 MVA, 40 MVA, 45 MVA, 50 MVA, 60 MVA, 75 MVA, 90 MVA, 100 MVA, 120 MVA
Typical high voltage ratings for station class transformers are: 230000 Delta, 161000 Delta, 138000 Delta, 115000 Delta, 69000 Delta, 46000 Delta, 34500 Delta, 27600 Delta, 24940 Delta, 22900 Delta, 13800 Delta, 13200 Delta, 12470 Delta, 4160 Delta, or 2400 Delta
Typical low voltage ratings for station class transformers are: 34500Y/19920, 24940Y/14400, 14400 Delta, 13800Y/7970, 13200Y/7620, 13090Y/7560, 12470Y/7200, 6900 Delta, 4160 Delta, 4160Y/2400, 2400Y/1385, 2400 Delta, 600Y/347, 600 Delta, 575Y/332, 480Y/277, 480 Delta