Test Laboratory for Transformer Materials
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Test Laboratory for Transformer Materials
Test laboratory for transformer materials
Do you know the chemical age of your transformer? Well we do!
There are numerous complementary methods for diagnosing the transformer ageing process early and reliably. The Siemens Test Laboratory for Transformer Materials is completely focused on the laboratory diagnostics of oil-filled electrical equipment. The highly qualified personnel are constantly developing new methods for ageing diagnostics and are using this knowledge for the benefit of our customers.
Accredited as an independent test laboratory in accordance with ISO 17025 (Certificate)
Our services include insulating oil and material testing. The diagnostic test procedures vary between ageing analysis or condition detection of oils /insulating materials and the new state assessments of oils /insulating materials.
The lifespan of a transformer largely depends on the ageing of the solid and liquid organic insulating materials. In normal operating conditions, below the maximum permissible load, and with regular maintenance and care, a transformer's lifespan can be extended to well over 30 years.
Nevertheless, during the working life of a transformer abnormal events could occur, for example transient over voltages, overheating during emergency operation, dynamic stress and faults in the cooling. These processes result in an accelerated ageing of the transformer materials.
Whether it is a case of new construction, operation, retrofit or repair, it is always a matter of reliably recognizing material degradation and rectifying it. For this purpose an extensive knowledge of the materials as well as a specific, precise analysis is fundamental. In order to avoid costly breakdowns, minimize downtimes and extend the lifespan of a transformer, the performance of a regular trend analysis and targeted maintenance are indispensable.
The combination of moisture in the oil and in the cellulose is an indicator of ageing. The most important method for the diagnosis of the ageing process as a result of dielectric, thermal, dynamic and chemical ageing in oil and oil-paper insulation is the Dissolved Gas Analysis (DGA). The Siemens Test Laboratory for Transformer Materials offers a comprehensive service, from the collection of samples to analysis and assessment.
The sampling device, developed in collaboration with the customers, offers the following advantages:
During the mostly decades-long service life of a transformer, materials too are subjected to considerable ageing processes. Through our tests we are able to determine the condition of the materials, and offer our clients the possibility to plan any necessary maintenance measures early.
Analyses of solid insulating materials, conductive metallic materials (grain-oriented electrical steel and copper materials) as well as coating materials and sealing materials, are carried out.
The decomposition of paper is caused by the processes of hydrolysis, pyrolysis and oxidation. The degree of polymerization (DP-value) of paper was defined by IEC 60450 and it counts the number of polymerized glucose rings. During the paper decomposition, the DP-value is reduced and the tensile strength decreases. New cellulose has a DP-value of 1000-1100, aged cellulose on the other hand has a value of only 150-200, which means the end of the transformer's lifespan.
As it is not possible to take paper samples during running operation, the condition of the solid insulation is estimated based on the cellulose decomposition products (2- Furfural). For this purpose a regular trend analysis is necessary.
The furan content in oil depends on:
An exact link between the furan content and DP-value cannot be deduced at present. However it is possible to make a trend analysis: based on the change of the furan content, information about thermal conduct of the solid insulation over the years can be obtained.
Material Testing Laboratory - Analysis for Transformers
Electrical Research and Testing Laboratory Nuremberg
Accreditation Certification - Annex
Chemical physics laboratory
Katzwanger Str. 150
90461 Nürnberg, Germany
+49 (0) 911 - 434 -2324