II. Components
Parts and assemblies to be reconditioned under Section 2400 Medium Voltage Transformers include but are not limited to:

• Frame, Enclosure, Tank
• Phase, through or neutral bus
• Ground Bus
• Ground Link, Grounding Pad
• Bus Support
• Tap Board
• De-energized Tap Changer*
• Dual Voltage switch*
• Windings
• Fuse Block
• Core
• Core Yoke
• Monitor Panel
• Thermostat
• Cooling Fans
• Control Relays
• Meters, Gauges, Instruments
• Arrestors, surge/lightning
• Radiators
• Bushings
• Valves
• Pressure Relief Devices*
• Cutouts
• Bay-O-Net Fusing*
• Dead-front inserts*
• Dead-front Wells*
• Nameplate or Label
• Terminal or polarity markings
• Third Party Certification Labels or Marks
• Air Terminal Chambers

III. Testing and Inspection
The PEARL Section 2400 Medium Voltage Transformers standards begins with the definition of the term "Reconditioning" as "the process of returning electrical equipment to safe and reliable operating condition based upon the design of the original manufacturer at the time of manufacturing." This is followed by reference tables used to calculate test results and tolerances and the necessary test equipment required by the PEARL Section 2400 Medium Voltage Transformer Standard. The medium voltage transformer standards continue with a "Recondition Evaluation," which is a detailed inspection of all parts of the medium voltage transformer, including but not limited to the components listed above.

Section I for PEARL Section 2400 Medium Voltage Transformers begins with reference table identification and a list of required test equipment. The following test equipment is required to perform the testing requirements of this reconditioning standard:

1. Insulation Resistance Test Set (Megohmeter) 1000 Vdc minimum

One of the following pieces of test equipment is required to perform the transformer ratio verification testing requirements of this reconditioning standard:

1. Insulation Resistance Test Set (Megohmeter) 1000 Vdc minimum

One of the following pieces of test equipment is required to perform the turn-to-turn ratio verification testing requirements of this reconditioning standard:

1. Turns-To-Turns Ratio Test Set

2. AC Voltage Supply and Voltmeter (+/- 0.5%)

3. Transformer Winding Resistance Test Set

One of the following pieces of test equipment is required to perform the insulation resistance testing requirements of this reconditioning standard:

1. Power Factor Test Set

2. Dissipation Factor Test Set

One of the following pieces of test equipment is required to perform the overpotential testing requirements of this reconditioning standard if it is required by the customer:

1. AC Overpotential Test Set

2. DC Overpotential Test Set

Section II Recondition Evaluation-Inspection and Testing identifies each component and assembly part that must be inspected to determine the components viability and the reconditioning steps necessary to bring the transformer back to original operating condition. Results and notes from the pre-reconditioning inspection and test are recorded in the PEARL Reconditioning Evaluation and Test forms that accompany each respective standard.

IV. Reconditioning
Section III Reconditioning Procedures describes how to recondition each component and assembly, beginning with the disassembly of the medium voltage transformer down to its major subassemblies. Reconditioning for medium voltage transformer standards includes:

• Disassembly
• Cleaning
• Drying
• Re-Gasketing or Re-Sealing
• Deoxidizing
• Removal of corrosion
• Degreasing
• Plating
• Painting
• Lubricating
• Adjusting
• Filtering
• Add or replace oil
• Add gas

Assembly of the reconditioned components and subassemblies is followed by final inspection and testing. As with all testing, inspection, and reconditioning operations, final inspection and test results are recorded onto the Evaluation and Test forms included with the standard. If a PEARL certified technician follows the reconditioning standard, the medium voltage transformer assembly is eligible for a Blue PEARL Reconditioned Quality Seal.

Links to the full reconditioning standards for medium voltage transformers:
Link to the full Standard Number 2410
    Medium Voltage Dry-Type Transformers
Link to the full Standard Number 24200
    Medium Voltage Oil Filled Padmount Transformers
Link to the full Standard Number 2430
    Medium Voltage Gas Filled Padmount Transformers
Link to the full Standard Number 2440
    Medium Voltage Oil Filled Power Transformers

Link to view and/or download PEARL's 137 reconditioning standards for electrical equipment.