On May 27, 2025, the CEI – Italian Electrotechnical Committee hosted in Milan a technical seminar titled:
“Dielectric liquids for transformers: from mineral oil, through PCB, to esters”.

Sea Marconi took part as a sponsor and speaker, offering a perspective that bridges the past and future of asset and risk management for transformers.

The first presentation, by Vander Tumiatti, focused on the history and sustainable management of PCBs, especially in light of the regulatory deadline of December 31, 2025, which requires the decommissioning of equipment with PCB concentrations above 50 mg/kg.

The second contribution, delivered by Giuseppe Pecoraro, highlighted the value of fingerprinting as an advanced technique for precisely identifying insulating fluids and related issues such as corrosivity.

While the CEI event provided some interesting ideas, it lacked in-depth technical discussions or real participant interaction.

That’s why Sea Marconi is relaunching the importance of technical dialogue and professional training with My Transfo 2025, to be held in Turin on October 14 and 15.

The event, organized by Sea Marconi, will feature customizable training sessions to explore key topics for professionals dealing with transformers, insulating fluids, maintenance, diagnostics, and sustainability.

Two full days of high-level content, real case studies, discussions with international experts, and valuable technical networking opportunities.

Check out the agenda and register at www.mytransfo.com

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EURODoble 2024, celebrating its 30th anniversary, will be held from October 7 to 10, 2024, in Manchester. EURODoble is a key platform for experts to share knowledge and innovations in the energy sector. The event continues its mission to address industry concerns through education, discussion, and collaboration.

Sea Marconi’s participation in this high-level event underscores our ongoing commitment to innovation and excellence in transformer and insulating fluid management. Riccardo Maina’s presentation will showcase our expertise in retrofilling with natural esters, emphasizing the critical importance of fluid-atmosphere segregation.

Abstract of Riccardo Maina’s Presentation

A growing number of transformers filled with mineral oil are being retrofilled with natural esters. These esters are recommended only for sealed units with segregation from the atmosphere (IEC 62770). Numerous cases show that this recommendation is overlooked, leading to rapid fluid aging and significant changes in its chemical-physical properties. This paper reports such cases and non-invasive procedures for fluid segregation from the atmosphere, even for smaller transformers. Optimized methods for retrofilling with natural esters are also described.

The post ***UPDATE*** EURODoble 2024: Sea Marconi Brings Expertise in Retrofilling with Natural Esters to the Stage appeared first on Sea Marconi.

Electric transformers are key components in any electrical distribution system, used to convert voltage from one level to another (from production to usage). MT/BT distribution transformers are essentially of two types: oil-filled and dry-type. Oil-filled transformers consist of a metal casing containing mineral oil, which serves the function of electrical insulation and heat dissipation, while dry-type transformers can be air-cooled or have windings encapsulated in resin.

SEA MARCONI is the first company in the world to have developed a monitoring system for the health status of resin transformers: Smart Nosy

How to select the correct transformer type?

The choice of the suitable transformer depends on various factors:

Context of use

Due to the insulating material used (resin vs oil), resin transformers are particularly suitable for environments with high risk of fire or pollution, such as shopping centers, hospitals, chemical industries, and marine applications. Oil-filled transformers are preferred in applications with high voltage and strategic contexts, even outdoors, where high reliability and durability over time are required.

Voltage at play

Oil-filled transformers reach higher powers (production and energy transmission), while resin transformers are used up to voltages of 36 kV for powers of 30 MVA (distribution). Air-cooled transformers usually stop at 20 kV.

Logistic constraints

Thanks to their reduced weight and compact dimensions, resin transformers are easy to transport and install, even in confined spaces. In these contexts, dry-type transformers avoid the double handling of the insulating fluid and the apparatus. Oil-filled transformers can be installed outdoors, while resin transformers require a cabinet or cells to protect them from the weather.

Costs

The cost of the asset, with the same installed power, is essentially comparable between the two technologies. Analyzing the total cost over the life cycle, there is a misconception that oil-filled transformers represent a higher expense due to checks and maintenance, while, with a closer analysis, it should be considered that resin transformers require constant maintenance of the cabinet housing them, since a “dirty” environment significantly affects their operation and consequently the failure rate of the asset. Speaking of costs, there are certainly differences related to installation and mandatory fire safety measures, which are considerably more stringent in the case of oil-filled transformers.

Sustainability

This area is becoming increasingly important in adopting one technological solution over another. Typically, resin transformers are considered a more environmentally friendly choice due to the absence of oil (a potential contaminant of groundwater in case of spills); however, it should be noted that there is an environmentally sustainable alternative, namely natural vegetable fluids (natural esters). Natural esters are almost completely biodegradable and, having a very high flash point, are an extraordinary response to the risk of fire.

Expanding the concept of sustainability beyond environmental aspects, we must mention the end-of-life phase of the asset. We could say that the disposal and replacement phase is simpler for resin transformers, which, however, have a significantly shorter overall lifespan compared to oil-filled transformers.

Monitoring/Maintainability

Here lies one of the main differences between the two types of transformers. Oil-filled transformers allow monitoring through fluid analysis in the laboratory and, for the most important and strategic machines, there are also devices capable of online monitoring of key parameters. Those in resin do not require maintenance, except for the cabinet housing them, and do not allow monitoring of their health status. The absence of maintenance of resin transformers is often seen positively due to a reduction in total operating costs. However, if we connect it to a higher failure rate and the inability to monitor their health status, the main weakness of resin transformers emerges: absence of alert/alarm signals that can improve efficiency in managing the asset and productivity.

The post Resin Transformers vs Mineral Oil Transformers: Costs, Applications, and Sustainability appeared first on Sea Marconi.

In the last 2 years Sea Marconi has assisted, and has been directly involved, on several cases of failure related to corrosion phenomena on the silver contacts of the selectors, with very significant consequences in terms of damage and lack of production (losses). Sea Marconi has identified and defined a new pathology: “C5 – Corrosion of silver contacts from total sulfur compounds“.

Here are the facts we are aware of. Last year in Italy Sea Marconi learned of a catastrophic failure on a 440 MVA, 400 KV GSU step-up transformer, with evidence of silver sulfide on the selector contacts. The same evidence was found in Brazil, Colombia and Argentina on highly strategic 500 KV HVDC equipment during 2021 and 2022. These events add up to the failure cases cited in a 2021 IEEE article that says “In Australia, most of the transformer that are failed due to silver sulphide corrosion were originally filled…”*

The My Transfo 2023 meeting conference (Turin, 3-4 October 2023) will be an opportunity to share and deepen this significant criticality, identifying new risk assessment strategies. Precisely for this purpose Dr. Sameera Samarasinghe, the author of the article on the cases in Australia cited above: *”A Risk Assessment for Utilities to Prevent Transformer OLTC Failures Caused by Silver Sulphide Corrosion,” in IEEE Transactions on Power Delivery, 2022.

The corrosion phenomena, more than 30 years after the first cases of corrosion of 500 KV shunt reactors in Colombia (type C1 – from DBDS), require technical and regulatory updating. At My Transfo will also be present prof. Shubhen Kapila, convenor of the working group that led to the publication of the 3 parts of IEC 62697 “Test methods for quantitative determination of corrosive sulfur compounds in unused and used insulating liquids”.

Click here to see the agenda of My Transfo 2023 – Sustainability, Asset, Risk, Solutions

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In addition to this intervention, Sea Marconi intervened at the Eurodoble with two other speeches:

• “Filling New Power Transformers with Insulating Fluid Prior to the First Energization: Best Practices” held by Eng. Riccardo Actis (technical service manager), and
• “Additives in Natural Ester: Their Efficacy and Degradation Rate Under Thermal Aging Conditions” held by Riccardo Maina (laboratory manager).

The Eurodoble was also an opportunity for Sea Marconi to show the participants 2 absolute novelties: the SmartNosy and the DGA Experience.
SmartNosy is the first system in the world for monitoring the state of health of cast resin transformers. DGA Experience is a package of services, products, solutions for laboratories that intend to improve their performance in the analysis of dissolved gases. I won’t dwell here on the extraordinary innovations introduced by these two services, I invite you to click on the links just above to learn more.

The post Eurodoble Rome, a great opportunity for professional enrichment appeared first on Sea Marconi.

Solid and liquid insulating materials for high temperature, applications and case histories
>> Richard Marek – Dupont (USA)
Characterization of different cellulose types using dielectric frequency response (FDS)
>> Britta Pfeiffer – Omicron (Austria)
Increasead Loadability of Transformers Immersed in Natural Esters
>> Fabio Scatiggio – Terna (Italy)

Round Table on “Natural esters” with
>> to be defined – A&A Fratelli Parodi (Italy)
>> Kevin Rapp – Cargill (USA)
>> to be defined
>> Russel Martin – M&I (UK)
Moderated by Fabio Scatiggio* – Terna (Italy)

Degradation phenomena of natural esters
>> Riccardo Maina – Sea Marconi (Italy)
Qualification of Insulating Liquids for Tap-Changers
>> Rainer Frotscher – MR (Germany)
Predictive and maintenance free tools and accessories for transformer and OLTC (or similar)
>> Stefano Vignali – MR (Italy)

Round Table on “DGA Online monitoring, techniques and devices” with
>> Donald Skelly – Qualitrol (Ireland)
>> Tony McGrail – Morgan shaffer – Doble  (USA)
>> to be defined
>> Marco Tozzi – Camlin (Ireland)
Moderated by Luc Paulhiac* – EDF (France)

Condition monitoring on asset health indices and probability of failure with lessons learned updates from the field
>> Tony McGrail – Doble (USA)

take a look to the complete agenda…

When will the definitive agenda be available?

We do our best to enrich the agenda until a few days before the event. Actually, the precise and definitive lineup of the interventions is not known, for this reason the registrations are discounted by 50% until 31st August.

See prices

The post The very first draft of the agenda is available appeared first on Sea Marconi.

A month has passed since My Transfo 2014 (Turin, 18 and 19 November 2014), the leading conference in Europe on insulating oil used in electrical apparatus. My Transfo has been held every two years since 2002, and each time, in particular prior to the last two editions, there has been doubt as to whether the famous international crisis would have had an impact on participation in the event. Fortunately not! To the contrary, My Transfo 2014 beat its own record of participants, giving life to a technical conference of the highest prestige and international standing.
More precisely, the number of participants was 150 (with peaks of almost 200 people) from 20 nations and 4 continents, with 95 companies represented; there were 26 speakers, the best experts in the industry, for a total of 28 speeches (plus a round table) split across two days. The speeches were almost all in English, supported by a team of 7 simultaneous interpreters, who translated the conference into four different languages: English, Italian, French and Spanish.

Click here to see the two-day agenda

Speeches were heard by Technical Directors, Technical Managers, laboratory technicians, researchers, Product Managers, production managers, energy transmission department managers, project leaders and project managers, Sales & Marketing Managers, high voltage maintenance managers, electro-technical engineers and specialised supervisors. The contribution of the public represented an added value for My Transfo, with questions giving life to extremely animated discussions, allowing the various topics to be discussed at a practical and truly useful level.

We would in fact like for My Transfo to continue to be a point of reference given the quality of the themes dealt with, but which at the same time offers suggestions and ideas that participants can adopt on a daily basis.
For the first time, following a single adhesion in 2002, My Transfo enjoyed contributions by an impressive 7 sponsors (Cargill, Ergon, Volta, a.Eberle, MTE, Mobitron, Protocube). These sponsors, thanks to the increased popularity of My Transfo edition after edition, first invested and subsequently confirmed that our event is an extraordinary opportunity through which to offer solutions that are truly relevant to the target audience.

Sea Marconi, the promoter and organiser of the event, not only successfully achieved its objective, but also went beyond. The number of adhesions was greater than expected, participant satisfaction was high, but above all, the original spirit of My Transfo was preserved: the sharing of high-level scientific information and an exchange of knowledge and experiences in the use of insulating oil in electrical apparatus, and all that which relates to this subject.

 

Click here to view photos and videos of the event
Click here to download the conference proceedings
Click here to connect to the Linkedin and Google+ page.

The post My Transfo 2014 beat its own record of participants and has been confirmed as the no.1 conference in Europe appeared first on Sea Marconi.

Chile depolarisation. One of the most “extreme” missions performed by Sea Marconi has been concluded successfully: the treatment of 6 transformers in the desert of Atacama in Chile, the driest place in the world, at 9,000 feet altitude with a temperature range between day and night of more than 30 °C.

Our operational engineers were able to adapt to really difficult conditions such as for example, total isolation, the altitude, climatic conditions. Correlated news.

In details, the activity performed by our engineers  has been the selective depolarisation from corrosive sulfur (C1 – DBDS & Corrosive Sulfur) on very large transformers, almost 120 tons of oil for each piece of equipment (250 MVA, 345 KV).

The Customer, AES an American multi-national in the energy field, really demonstrated its appreciation for the job done by Sea Marconi. Shortly, in fact, a “4-hands paper” that AES shall present as a case history of best practice for the management of the corrosive sulfur problem is going to be issued.

The mission in Chile emphasised and saw the situation first-handed the effectiveness of the sustainable solutions by Sea Marconi for the Life Cycle Management also in South America. This success has already echoed in Colombia, Panama and Uruguay, where the Chedcos depolarisation by Sea Marconi is going to be adopted as a really effective response to the problem of the corrosivity of insulating oils.

The post The depolarisation from corrosive sulfur in the desert of Atacama in Chile has been concluded successfully appeared first on Sea Marconi.

Scenario

Company involved in production of primary aluminum with 8 rectifiers transformers

Nameplate data of the transformers:

Transformer: rectifier, ODAF with membrane
Manufact: xxx
Year: 1998
Power [MVA]: 93,4
Voltage [KV]: 66
Oil mass [Kg]: 27.200
Oil type: naphthenic

Step 1

First failure with discharges of high energy (D2)

Step 2

Post failure analysis, oil fingerprint with identification ant quantification of the copper sulphide on enameled contacts

Step 3

Sea Marconi expertise recommended the selective depolarization treatment (Chedcos)

The post Removal of corrosive sulfur with DBDS (C1) <strong>Pacific region 2012</strong> appeared first on Sea Marconi.

Scenario

Company in the chemical business, 4 GSU transformer

Nameplate data of the transformer:

Manufatc: xxx
Year: 2000
Power [MVA]: 47
Voltage [KV]: 34
Oil mass [Kg]: 12.000
Oil type: naftenico

Solution

Solution: Selective depolarization treatment (Chedcos) performed on-ste and on-load (transformer in service e fully load during the treatment).

The treatment has guaranteed DBDS < 10 mg/kg.

	Before treatment	After treatment
DBDS [mg/Kg]	125	< 5
H2O [mg/Kg]	7	3
TAN [mg KOH/g]	< 0,095	< 0,01
DF	0,0190	0,0033

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