IEEE C57.12.38-2014 pdf free

IEEE C57.12.38-2014 pdf free.IEEE Standard for Pad-Mounted-Type, Self-Cooled,Single-Phase Distribution Transformers 250 kVA and Smaller: High Voltage, 34 500 GrdY/19 920 V
and Below;Low Voltage, 480/240 V and Below.
No applied-voltage test is required on the high-voltage winding. Induced-voltage tests shall be performed by applying between the terminals of one winding a voltage that will be developed from the high-voltage line terminals to ground. This voltage shall be 1000 V plus 3.46 times the rated transformer winding voltage, but in no case shall the line-to-ground voltage developed exceed 40 000 V for 125-ky BIL or 50 000 V for l50-kV BlL. For this test, the neutral terminal shall be grounded. The voltage in the inducedvoltagc test shall be applied on the low-voltage winding.
When high-voltage terminations arc used that fall under IEEE Std 386. they may not be suitablc for chopped-wave testing; therefore, when terminations to lF.F.E Std 386 are used (bushing wells, 600 A integral bushings. etc.), chopped-wave tests are not required.
A pad-mounted. compartmental-type transformer shall confomi to IEEE Std C57.12.28 or IEEE Std (‘57.12.29 and consist of a tank with high-voltage and low-voltage cable terminating compartments. as shown in Figure 1 through Figure 5 of this standard.
Compartment configuration The high-voltage and low-voltage compartments shall be located side by side on one side of the transformer tank. When viewed from the front, the low-voltage compartment shall be on the right.
Access to the termination compartment shall be provided by removing a pentahead device or bolt and a locking device (Sec IEEE Std C57.12.28 for typical construction).
High-voltage and low-voltage compartments
The compartment door or doors shall be of sufficient site to provide adequate operating and working space when removed or opened. The door or doors shall either be equipped for latching in the open position or designed for manual removal, The hinge assembly shall include a captive means, such as a roll pin, to prevent accidental removal of the door or doors when they are in the open position.
If individual compartment doors are provided, they shall be so constructed as to provide access to the highvoltage compartment only after the door to the low-voltage compartment has been opened. There shall be one or more additional fastening devices that must be removed before the high-voltage door can be opened.Transformers with high-voltage bushings (see Figure 5) shall have the following additional features:
-Protection against accidental contact with live parts shall be provided along with an additional door or lift-out panel that must be removed before acess can be gained to the high-voltage compartment.
-If the transformer is supplied with fuses in the high-voltage compartment, the compartment door or doors shall be adequate to withstand gas pressures incidental to the fuse operation at the maximum rated interrupting capacity of the fuse.
7.5 Pad attachment The bottom edges of the compartments shall be so constructed as to provide for the use of hold down devices that are accessible only from the inside of the compartments.IEEE C57.12.38 pdf free download.