Chemical- physical analyses

Insulating media



Insulating media

The service portfolio includes the monitoring of transformers, e-coils and instrument transformers with the help of chemical-physical analysis of the insulating oils. The assessment is based on the recognized standards EN 60422, EN 60296 and EN 60599.

The examination parameters and the examination intervals depend on various factors such as device status, voltage level and system relevance. Hence, our services also include individual counseling regarding the optimal examination program.

Our services

Gas-in-oil analysis DGA (Töpler pump/GC) EN 60567
Gas-in-oil analysis DGA (Headspace/GC) --
Polychlorinated biphenyls (PCB) EN 12766 / Verf. B
Furfural and related compounds (furans) EN 61198
Degree of polymerization of paper IEC 60450
Appearance / purity ISO 2049
Color number ISO 2049
Refractive index at 20°C DIN 51423-2
Density (flexural bar method) DIN EN ISO 12185
Kinematic viscosity (per temperature point) ISO 3104
Water determination (coulometric) IEC 60814
Total pollution (GV) IEC 60422 / Annex C
Neutralization number (NA) EN 62021
Saponification number (VZ) DIN 51559
Interfacial tension vs. water (incl. density) ASTM D971-99a
Flash point (Pensky-Martens) ISO 2719
Breakdown voltage IEC 60156
Dissipation factor (90°C) IEC 60247
Inhibitor content (FTIR spectroscopy) IEC 60666
Aromatic content (FTIR spectroscopy) IEC 590
Particle content (cleanliness class) EN 60970
Potentially corrosive sulfur (qualitative test) ÖNORM EN 62535
DBDS (Corrosive sulfur conductor) IEC 62697-1
Passivator content (HPLC) DIN IEC 60666
GC-MS screening (to determine the type of oil) --
Method for stray gassing under thermo-oxidative stress IEC 60296 Annex A (2020)
Gassing Characteristics of Insulating Liquids under Thermal Stress at Low Temperature (Stray Gassing) ASTM D 7150 Method A

In addition to the standard analysis of insulating oils, special questions can be dealt with by VUM:

  • Post-mortem examinations (Dp-value distributions, furans in the paper including sampling)
  • Determination of hydroperoxides (beginning of oil aging) in insulating oils
  • Research and processing of specific questions on insulating oil analysis and materials in high-voltage technology

Databased condition assessment of equipment filled with insulating media

Due to the large amount of data in the field of insulating oil analysis with more than 700,000 analysis results for around 20,000 devices, VUM has a valuable database that is unique in the field of converter diagnostics.

Data evaluations together with additional external variables such as weather data, strains or the history of the equipment allow a profound understanding of the aging behavior of oil-filled equipment. Characteristics of individual manufacturers, types, years of construction or similar can also be analyzed in this way. For a more accurate assessment of the condition of the device, the comparison of individual conspicuous pieces of equipment with similar devices of the same type and age is of particular value.