Oil change, replacement – Retrofilling

Sea Marconi’s typical approach is to avoid replacement of a deteriorated oil, preferring to treat it (in a manner similar to dialysis) in order to restore it to “as new” condition, while simultaneously “cleaning” the transformer. The treatments (with respect to oil change) are economically more advantageous, avoid the risks associated with the handling of huge amounts of oil and protect the environment because they avoid the disposal of a resource (insulating oil) that is still usable.

When the oil is in a very advanced state of deterioration or when treatment is not convenient from an economic point of view, Sea Marconi is also able to perform the operation of changing the oil load. This operation has several phases and many critical issues (logistical, functional and environmental), so it is always advisable to rely on a professional and competent operator.

“Sea Marconi solutions”   vs   “Change of oil”

Key factors Sea Marconi closed-loop treatments* Oil change
On-Load Mode Yes No Off-Load for emptying and filling
Need for new oil No Yes 125%/150% of initial oil mass**
Old and new oil compatibility Safety Attention  to base oil, additives, others**
Recovery: Physical properties KV, DGA, H2O Yes Attention *** sonly after closed-loop treatment of new oil §11. 2. 3 (IEC 60422 Ed. 4 2013)
Recovery: chemical properties TAN, DF, IFT Yes Attention *** only after physical treatment + closed-loop depolarisation of new oil §11. 3 (IEC 60422 Ed. 4 2013)
Removal: DBDS & Corrosive Sulfur Yes Attention *** only if initial DBDS < 80 mg/kg or after “reclamation” with a special adsorbent
Desludging and dehydration of solid insulators Yes Attention *** sonly after physical treatment + closed-loop depolarisation of new oil §11. 3 (IEC 60422 Ed. 4 2013)
Decontamination: dissolved metals Yes Attention *** sonly after “reclamation” with special adsorbent and if the initial value is 8/10 times higher than the target value
Dehalogenation:PCBs/POPs in the oil Yes Attention *** only if the initial PCB is 8/10 times higher than the target value
Self-cleaning of DBDS, PCB/POPs from decontamination unit Yes No cross contamination***
Cross contamination da DBDS,  PCB/POPs Safety Attention ***
Partial discharges: air bubbles and incoming moisture Safety Attention – Particular attention to damp insulators
Risks for oil handling Safety Attention to high impact of logistics
Disposal of oil and PCB waste No especially if the PCB is higher than the allowable limit

* Treatments integrated with Mobile Decontamination Unit (MDU) using closed-loop processes patented by Sea Marconi

** Compliant with IEC 60296 Ed. 4 2012

*** Because of old oil that remains impregnated mainly in solid insulators

1. Emptying

Utmost attention must be paid in particular to emptying of the transformer, which leads to a vacuum in the casing (where possible), but complying strictly with the operating protocols of the machine’s manufacturer or the customer.

2. Treatment and filling

Depending on the transformer in which it will be used, new oil should be treated both when it is still in the tank and after it is placed in the transformer. In addition to responding to regulatory requirements, this operation is necessary in order to ensure that new oil is not contaminated by the oil residue (cross-contamination) that remains impregnated in the inner parts of the transformer and accounts for about 15% of the total quantity.

Sea Marconi performs these activities with absolute professionalism, respecting sector guidelines and the most stringent safety standards of the customer. The main phases are as follows:
  1. Transport, installation and connection of the treatment equipment
  2. Initial analytical checks
  3. Emptying of the transformer
  4. Filling of the transformer
  5. Treatment of new oil
  6. Level and vent checks
  7. Replacement of desiccant salts with silica gel;
  8. End-of-operation analytical checks
  9. Removal and transportation of treatment units and tanks

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