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  2. Distribution transformer - Wikipedia

    en.wikipedia.org/wiki/Distribution_transformer

    Distribution transformers typically have ratings less than 200 kVA, [3] although some national standards allow units up to 5000 kVA to be described as distribution transformers. Since distribution transformers are energized 24 hours a day (even when they don't carry any load), reducing iron losses is vital in their design. They usually don't ...

  3. Volt-ampere - Wikipedia

    en.wikipedia.org/wiki/Volt-ampere

    VA ratings are also often used for transformers; maximum output current is then VA rating divided by nominal output voltage. [6] Transformers with the same sized core usually have the same VA rating. The convention of using the volt-ampere to distinguish apparent power from real power is allowed by the SI standard. [7] [page needed]

  4. Orders of magnitude (current) - Wikipedia

    en.wikipedia.org/wiki/Orders_of_magnitude_(current)

    400 V low voltage secondary side distribution transformer with primary 12 kV; 200 kVA (up to 1000 kVA also common) [7] 10 3: 2 kA 10.5 kV secondary side from an electrical substation with primary 115 kV; 63 MVA [8] 9.3 kA 2.7V, Ultracapacitor short circuit current [9] 10 4: 25 kA Lorentz force can crusher pinch [10] 30 kA Typical lightning ...

  5. Pad-mounted transformer - Wikipedia

    en.wikipedia.org/wiki/Pad-mounted_transformer

    ANSI C57.12.00 – Standard General Requirements for Liquid-Immersed Distribution, Power, and Regulating Transformers ANSI C57.12.22 – Standard for Transformers - Pad-Mounted, Compartmental-Type, Self-Cooled, Three-Phase Distribution Transformers with High-Voltage Bushings, 2500 kVA and Smaller: High Voltage, 34,500Grd/19,920 Volts, and Below ...

  6. Per-unit system - Wikipedia

    en.wikipedia.org/wiki/Per-unit_system

    The ratio of the voltage bases on either side of a transformer is selected to be the same as the ratio of the transformer voltage ratings. With these two rules, a per-unit impedance remains unchanged when referred from one side of a transformer to the other. This allows the ideal transformer to be eliminated from a transformer model.

  7. Single-wire earth return - Wikipedia

    en.wikipedia.org/wiki/Single-wire_earth_return

    The transformers are usually rated at 5 kVA, 10 kVA, and 25 kVA. The load densities are usually below 0.5 kVA per kilometer (0.8 kVA per mile) of line. Any single customer's maximum demand will typically be less than 3.5 kVA, but larger loads up to the capacity of the distribution transformer can also be supplied.

  8. Electric power distribution - Wikipedia

    en.wikipedia.org/wiki/Electric_power_distribution

    Transformers step down transmission voltages, 35 kV or more, down to primary distribution voltages. These are medium voltage circuits, usually 600–35 000 V. [1] From the transformer, power goes to the busbar that can split the distribution power off in multiple directions. The bus distributes power to distribution lines, which fan out to ...

  9. Three-phase electric power - Wikipedia

    en.wikipedia.org/wiki/Three-phase_electric_power

    Three-phase transformer with four-wire output for 208Y/120 volt service: one wire for neutral, others for A, B and C phases. Three-phase electric power (abbreviated 3ϕ [1]) is a common type of alternating current (AC) used in electricity generation, transmission, and distribution. [2]