IEEE C57.12.2-2016 pdf free
IEEE C57.12.2-2016 pdf free.IEEE Standard for Submersible,Three-Phase Transformers, 3750 kVA and Smaller: High Voltage, 34 500 GrdY/19 920 Volts and Below;Low Voltage, 600 Volts and Below.
The switch rotation shall be clockwise to close, to energize the high-voltage windings, and counterclockwise to open, to de-energize the high-voltage windings.
7.3.3.4 Loadbreak switch current-carrying capabilities
The minimum current-carrying capabilities of the switch shall be 200 A (continuous current rating) and 10 kA rms symmetrical for 0.17 s (short-time current rating).
7.3.3.5 Loadbreak switch material
All parts of the loadbreak switch external to the tank shall be of corrosion resistant material other than aluminum and plastic.
7.3.4 Overcurrent protection
To maintain tank integrity, and to disconnect the transformer from the primary circuit in the event of faults, including intermal low impedance faults, the transformer shall be equipped with either one of the following
a) Full range, current-limiting fuses in dry-well canisters, or
b) Bayonet fuses in series with under insulating liquid partial-range, curren-limiting fuses
7.3.4.1 Full range, current-limiting fuses
If full range dry-well canisters with crrent-limiting fuses are specified, they shall be
a) Cover mounted and clearly marked as FI, F2 and F3 with stainless steel tags fastened to the cover.
b) Fuses shall be of the non-gassing type and explicily designed for use in sealed dry-well canisters.
c) Interlocked mechanically with the load-break switch described in 7.3.3 to allow access to the dry- wells only when the switch is in the open position. The dry-well canisters and affixed fuses shall be operable with standard hot line tools.
7.3.4.2 Bayonet fuses If bayonet fuses are specified
a)The bayonet fuse holders shall be of the submersible type and located on the transformer cover, and shall be operable with standard hot-line tools. The fuses shall be clearly marked as F1, F2, and F3 with stainless steel tags fastened to the cover.
b) Partial range, currnt-limiting fuses shall be located inside the tank. They are not intended to be externally acessible nor field replaceable.
c) The primary circuit, starting at the high-voltage bushings, shall conneet to the partial-range,current limiting fuses, the transformer load-break switch and the bayonet fuses, in that order.
d) Unless otherwise specified, the bayonet fuses shall be interlocked mechanically with the load-break switch described in 7.3.3 to allow access to the bayonets only when the switch is in the open position.
e) A submersible pressure relief valve or device shall be placed near the bayonet fuses with appropriate caution label about operating before attempting to remove a bayonet fuse (sce Annex A).
7.3.5 Protective covers
The transformer shall be shipped with protective covers on the high-voltage connectors. The protective covers shall be ultraviolet (UV) light resistant, water tight and shall be secured to prevent loss during transportation, transit and storage.IEEE C57.12.2 pdf free download.
