Can I use Midel fluids to retrofill transformers at high voltages?

ANSWER:

For retrofilling transformers, it depends upon the voltage and power rating of the asset.

High Voltage Transformers using Midel fluids

Midel fluids are approved for use at transmission voltage levels by several leading OEMs. MIDEL 7131 has been used for multiple projects at 400kV and in mobile test equipment up to 500kV. In common with other ester-based fluids, some design adjustment may be needed for higher voltage levels due differences in permittivity and dielectric performance.

Although MIDEL fluids are suitable for higher voltage levels in specifically designed transformers, retrofilling depends upon the voltage and power rating. As a general guideline the table below can be utilised.

More questions on ester fluids?

This post is one of the 15 top questions we get asked on retrofilling transformers with ester fluids. Here is the full list of the frequently asked questions on ester fluid retrofilling:

1. Miscibility: Which transformer oils are compatible with Midel ester fluids for retrofilling?
2. Free-breathing: Can I use Midel fluids in breathing transformers?
3. Insulation Regeneration: Will Midel fluids heal existing problems in a transformer?
4. Fire Safety: Which dielectric fluids classifications are important to understanding fire safety?
5. Cold Weather: How do Midel fluids perform in the cold?
6. Moisture: What happens to the performance of Midel fluids when they absorb moisture?
7. Acid Levels: If Midel fluids have high acid levels, how do I recondition my fluid?
8. DGA: How can I use dissolved gas analysis on Midel fluids?
9. Power Factor: What is the Power Factor of Midel fluids?
10. Materials Compatibility: Are Midel fluids compatible with all transformer materials?
11. HV Applications: Can I use Midel fluids to retrofill transformers at high voltages?
12. Interfacial Tension: Is interfacial tension a meaningful property for Midel fluids?
13. Reusability: How are used Midel ester fluids processed and handled?
14. De-rating: Will there will be any derating of a transformer by changing it from mineral oil to a Midel ester fluid?
15. Retrofill Process: Are there extra requirements or steps when retrofilling transformers with Midel fluids?