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.

Hydro power plant

Nameplate data of transformer:

Transformer: GSU transformer
Power [MVA]: 30
Voltage [KV]: 130
Oil mass [Kg]: 58.000
Oil type: paraffinic

Solution: Selective Depolarization treatment (Chedcos) performed on-load (transformer fully load during the treatment)

Selective depolarization treatment (Chedcos) in order to remove corrosive sulfur compounds and dehalogenation treatment (CDP Process®) in order to remove the PCBs from oil and transformer. The treatment was performerd on-site and on-load (transformer in operation and fully load during the treatment).

*The agreed guarantee was PCBs < 40 [mg/Kg]

4 GSU transformer at thermal power plant

Nameplate data of the transformers:

Manufact: xxx
Year: 1997
Power [MVA]: 192
Voltage [KV]: 400
Oil mass [Kg]: 58.000
Oil type: naphthenic

Failure caused by discharges of high energy

Internal inspection and post failure analysis performed by Sea Marconi experts

Download the flier PDF: Sea Marconi Treatments Vs Fuller Earth treatments ENG (377.5 KiB)

*CDP Process^® for PCBs/POPs chemical dehalogenation; CHEDCOS for DBDS & Corrosive Sulfur Selective Depolarization

Post Failure diagnosis on a Grid Transformer showed signs of electric arcs on tap selector contacts. The failure has been caused by the formation of Corrosive Sulphides as CuS, Cu2S, Ag2S, etc. Indeed «At relatively high temperature, sulphur-containing oil molecules may decompose and react with metal surface to form metal sulphides» (IEC 60422 Ed. 4 – 2013 art. 5.17). This mechanism started together with the oil regeneration process with reactivation of sorbent and fuller earth column by uncontrolled combustion (> 370 °C). The Sulfur Compounds naturally present (DiBenzoThioPhene – DBTP, etc.) in the Oil and additives (DBDS, etc.) are decomposed in Sulfur Degradation ByProducts. Other Ref. National Grid (UK), ABB (Sweden), 2010 Doble Conference (USA)

• 45 years of Innovation for Life Cycle Management of Oils & Transformers;
• Solutions based on Global and Integrated Approach, Case histories, State of the Art, IEC Standards, CIGRE Guidelines, Stockholm Convention on POPs (Persistent Organic Pollutants);
• Opportunity for prevention and/or mitigation of losses and risks for the asset, workers, public health and environment;
• Focus on hot topics and priorities for strategic electrical equipment filled with insulating fluids;
• Diagnosis (> 150,000 cases) and Integrated Treatments (> 700 Power Transfos – 2012) with DMU (25 Decontamination Mobile Units), guarantee independent expertise, reliability, quality control (ISO 9001-2008, ACCREDIA ISO 17025), traceability, economic benefits, environmental protection, social, stakeholders and insurance relationship.

Last November 2012 Sea Marconi received the inspection visit for the surveillance and extension of the accreditation by Accredia*. The audit ended with a positive result and the new certificate is going to be effective on 25^th February 2013.

In particular, the Accredia inspectors scrutinised not only the laboratory, but the entire company, verifying with the utmost attention the full compliance with the prescribed procedures. At the end of the visit, which Sea Marconi passed brilliantly, the inspectors didn’t find any non-conformity, entering only eight observations, all of which already started toward the analysis of the causes and the identification of countermeasures.

The accreditation by Accredia is a guarantee for quality by the accredited laboratory and company and is a very important requisite for the verification of the analytical performances and the procedures regulating the entire documental and data system flow within the company.

Thanks to all the accredited tests (see below) the Sea Marconi laboratory is one of the very few laboratories worldwide (in Italy it is the only one) able to offer a package of accredited tests fundamental for the diagnosis of electrical equipment with insulating fluids.

The participation by ACCREDIA to the Multilateral Agreement for Mutual Recognition (MLA) ensures that the Sea Marconi’s test reports are recognised and accepted at international level by all the Countries subscribing the agreements for mutual recognition

The asterisk in the first column indicates that for the corresponding test, the laboratory has discontinued issuing reports with the ACCREDIA marking.

Moreover, with reference to norm ISO IEC 17025 on measurement uncertainty, the Sea Marconi Laboratory periodically monitors its own performances also through the participation to international inter-laboratory circuits (RRT – Round Robin Test o Proficiency Test) achieving Z scores of absolute excellency.

Thus, the test report by Sea Marconi achieves a specific relevance in legal terms, when required, and is fully complying with Directives, Implementation Laws and Technical Norms of the sector (IEC, CENELEC, CEI etc.) assuring an independent and expert evaluation. The test report by Sea Marconi, together with other evaluation parameters is dynamically interpreted (with diagnostic algorithms and the Sea Marconi data bank on over 60,000 pieces of equipment) to ensure the best diagnostic coverage for the life cycle management (LCM) of fleets of equipment with insulating fluids, strategic units in the generation, transportation, distribution and use of electric power.

* Italian Accreditation Entity – it is the only national organism authorised by the State to provide an accreditation activity.

After the accreditation of the test of PCBs in February 2009, Sea Marconi has obtained last November 2010 from ACCREDIA a brilliant confirmation, by extending the accreditation to the tests of dissolved gases (DGA*, dissolved water and furanic compounds)* (see here below the detail of the accredited tests).

Created form the combination of SINAL and SINCERT, ACCREDIA is the only organism authorised by the Italian State to perform accreditation activities.

Once more the work of the Accredia inspectors in Sea Marconi, was not limited exclusively to a scrupulous evaluation of the technical and organisational procedures of the laboratory, but also to a keen check of the qualification of human and instrumental resources in all the areas of the company involved in the testing and calibration activities.

With this additional accreditation, the Sea Marconi laboratory becomes one among very few laboratories worldwide (the only one in Italy) able to offer a package of accredited tests fundamental in the diagnosis of electrical equipment with insulating fluids.

Thus, the accreditation brand on the Sea Marconi’s test report “operates as a passport on international markets, where the holder is not required to have its product, service or its professionalism subject to additional tests, inspections or verifications” [web site Accredia, page International Agreements pag. Accordi internazionali].

The accreditation of the single tests ensures that Sea Marconi’s laboratory on one side is fully complying with the analysis procedures and methods on the single matrices and in particular with the requisites of standard ISO IEC 17025 relative to the uncertainty of measurement, on the other side that it implements a constant monitoring of the performances also with the participation to international inter-laboratories circuits (RRT – Round Robin Test or Proficiency Test) achieving scores (Z score) of absolute excellency.

Thus, the Sea Marconi test report gets a specific relevance in legal terms, when required, and a full compliance with the Directives, implementation Laws or Technical standards of the sector (IEC, CENELEC, CEI, etc.) ensuring an independent and expert evaluation of the domain (since 1968, with 42 years of activity in over 30 Countries). The Sea Marconi test report, together with the other evaluation parameters, is dynamically interpreted (with the diagnostic algorithms and the Sea Marconi data bank on over 60,000 equipment) to ensure the best diagnostic coverage for the management of the life cycle (Life Cycle Management – LCM) of fleets of equipment with insulating fluids, strategic units in the generation, transportation, distribution and use of energy.Sea Marconi operates for the prevention of damages through the classification of the type and priorities of the functional and environmental criticalities as well as the correlated countermeasures to prevent and/or mitigate risks.

Sea Marconi opera per la prevenzione dei danni attraverso la classificazione del tipo e priorità delle criticità funzionali e/o ambientali nonché delle correlate contromisure per prevenire e/o mitigare i rischi.

*Complete list of the tests (6) in revision 2 of 23-11-2010

An asterisk in the first column indicates that, for the corresponding test, the Laboratory has discontinued the issue of reports with the SINAL brand.

Read more:

• Search of the laboratories accredited ACCREDIA
• EA (European Accreditation)
• IAF (International Accreditation Forum)