July 4, 2011

Electrical Engineering Terms - U

  • UCA - Utility Communications Architecture.
  • UD - Underground Distribution
  • UF - A thermoplastic insulated, underground feeder conductor or cable designed for use in wet locations, including direct burial.
  • UHV - See "Ultra High Voltage".
  • UL - Underwriters Laboratories, Inc. UL is located at 333 Pfingsten Road, Northbrook, IL 60062.
  • Ultra High Voltage (UFV) - Transmission systems in the ac voltage exceeds 800,000 volts.
  • Unbalanced Loads - Refers to an unequal loading of the phases in a three-phase system.
  • Underground Residential Distribution - (URD) Refers to the system of electric utility equipment that is installed below grade.
  • Underground Utility Structure - An enclosure for use underground that may be either a handhole or manhole.
  • Unidirectional Unit - Allows inputs to be measured in one direction only. The stated output range indicates the minimum and maximum input levels.
  • Unit Electrical Relay - A single relay that can be used alone or in combinations with others.
  • Unit Protection - A protection system that is designed to operate only for abnormal conditions within a clearly defined zone of the power system.
  • Universal Bushing Well - This 200 amp rated component is used as part of a system to terminate medium voltage cables to transformers, switchgear and other electrical equipment. Universal Bushing Wells are manufactured by the Elastimold Division of Thomas & Betts.
  • Unrestricted Protection - A protection system which has no clearly defined zone of operation and which achieves selective operation only by time grading.
  • UPS - Uninterruptable Power Supply
  • URD - Underground Residential Distribution.
  • USE - Underground Service Entrance conductor or cable.
  • USMA - Utility Supply Management Alliance, a utility industry conference held annually that is focused on the supplier/customer relationship.



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