TRANSFORMER NAMEPLATE (GENERAL REQUIREMENTS).

TRANSFORMER NAMEPLATE (GENERAL REQUIREMENTS).

The minimum information to be shown on a transformer nameplate depends on the KVA rating of the transformer as specified in the standards. The standards require the following information for transformers rated above 500 KVA

• Name of manufacturer

• Serial no

• Month/year of manufacture

• Cooling class. Where the class of transformer involves more than one rating, all ratings are shown. Windings having different ratings have their individual KVA ratings described. If the transformer has more than one temperature rating, these ratings are shown on the nameplate. Provisions for future cooling equipment are indicated.

• Number of phases

• Frequency

• KVA or MVA rating

• Voltage ratings. The voltage ratings of a transformer or auto transformer windings are separated by a dash (-).

• Tap voltages. The tap voltages of an individual winding are separated by a slash (/).

• Rated temperature rise, °C

• Polarity (single-phase transformers)

• Phasor or vector diagram (polyphase transformers)

• Percent impedance. The percent impedance isspecified between each pair of windings with the voltage connection and the KVA base stated. The percent impedance shall be tested.

• Basic lightning impulse insulation levels (BIL). The BIL of each winding and each bushing are specified.

• Approximate mass of the core and coils, tank and fittings, insulating oil, total weight, and heaviest piece.

• Connection diagram. The connection diagram shows all winding terminations with a schematic plan view showing all fixed accessories. The schematic plan view generally shows the low-voltage side ofthe transformer at the bottom . The location and polarity shall be shown for all current transformers used for metering, relaying, ordrop compensation.

• Installation and operating instructions references

• The word ‘‘transformer’’ or ‘‘auto transformer’’

• Suitability for step-up operation. Since the MVA rating is generally specified at the output winding at the nominal output winding voltage, theMVA rating for step-up operation will generally be different than the MVA rating for step-down operation, unless specified.

• Maximum positive and negative operating pressures of the oil preservation system, kPa or psi

• Maximum negative pressure of the tank for vacuum filling

• Liquid level below the top surface of the highest point of the highest manhole flange at 25°C

• Change in liquid level per 10°C change in liquid level

• Oil volume of each transformer compartment

• Type of insulating liquid. The nameplate shall also have the following note: ‘‘contains no detectable level of PCB (less than 2 PPM)at the time of manufacture.’’

• Conductor material of each winding.