Transformer Services

MOKO’ teams travel across the country safely installing, assembling, vacuum-filling and commissioning substation, power and GSU transformers with ratings and voltage as large as 500 MVA and 400kV respectively.

Assembly, installation & commissioning

Upon arrival on site, MOKO installs the transformer and assembles the components. We then pull vacuum on the transformer with a pump, which allows us to maximize our ability to remove moisture and air voids in the windings. The oil filling procedure involves circulating the oil through our processing rigs. The oil is heated, dehydrated and degassed before entering the transformer.

Transformer Electrical Testing

MOKO uses state-of-the-art equipment to electrically test transformers. Our testing equipment utilizes special advanced software, which allows us to accurately store and transfer the data to our customers and generate detailed reports. Our comprehensive testing program includes the following common tests. We conduct additional electrical tests upon request:

  • Transformer Turns Ratio (TTR)

  • Insulation Resistance (Megger)

  • Winding Resistance

  • Current Transformer Ratio

  • Power Factor Testing – Transformer & Bushings

  • Transformer Excitation Testing

  • Sweep Frequency Response Analysis

Oil reclamation & processing

Over time, byproducts formed inside the transformer decompose the cellulose insulation. These byproducts adversely effect the properties of the dielectric fluid and can cause the transformer to eventually fail. The MOKO process extends the transformer life by removing harmful contaminants that degrade the transformer’s insulation system. MOKO continuously heats and circulates the oil through multiple filters, fuller’s earth tanks and a vacuum dehydration column to remove contaminants, such as acid, water and dissolved gases. The heat from the energized transformer aids in removing moisture from the insulation and dissolving sludge buildup within the windings. At the end of the process, the transformer is clean with excellent oil properties.

Oil sampling & testing

Maintenance of substation transformers is often neglected, with potentially severe consequences. Transformers degrade over time, and failure to collect oil samples and conduct testing can allow problems to go undetected, causing increased operating costs and downtime. With proper oil maintenance, that degradation can be delayed significantly, resulting in increased transformer life. These vital tests can uncover several potential problems within a transformer, including evidence of soluble contaminants, dielectric contaminants, and acid materials. MOKO' will test your oil sample for any of the following: Oil sampling and testing is an essential component of a comprehensive transformer maintenance program. The MOKO Oil Testing Guide is a must for simplifying and explaining the most common testing methods and types, and interpreting the results.

  • Dielectric break down

  • Moisture

  • Winding Resistance

  • PCB

  • (DGA) Dissolved Gas Analysis

  • Other

Oil sampling and testing is an essential component of a comprehensive transformer maintenance program. The MOKO Oil Testing Guide is a must for simplifying and explaining the most common testing methods and types, and interpreting the results.

Field services & repairs

Whether it’s warranty repair for transformer manufacturers, or replacing components on older transformers, our expert crews perform internal inspection and repairs on transformers of all sizes. MOKO will also retrofit your aging transformers with new ones designed to fit within your existing configuration. Our experienced teams perform maintenance services that include:

  • Regasketing

  • Welding Repairs

  • Bushing Replacement

  • Radiator Replacement

  • Load Tap Changer

  • Internal and External Inspections

  • Transformer Retrofit

Our crews regularly work weekends and holidays to minimize your downtime.