Oil Testing Solutions on Dielectric Transformer Fluids

Transformer oil is a special type of oil that must have excellent electrical insulating properties and is stable at high temperatures in order to properly insulate and cool a transformer while it is energized. Some of the most important properties for transformer oil to have are high dielectric strength, thermal conductivity, and chemical stability, and ideally must keep these properties over the course of a transformer’s lifetime.

Although mineral oil has long been the fallback transformer oil, it no longer is the only reliable dielectric fluid available. Plant-based natural esters continue to replace traditional mineral oil in transformers around the world as users seek a more environmentally sustainable and reliable solution. An example is Cargill’s FR3 natural ester, a rapeseed dielectric fluid. Along with being 100% biodegradable, FR3r fluid is also non-toxic in soil and water and for humans and wildlife.

As transformer oils are subject to various electrical, mechanical, and chemical stresses while a transformer is in operation it is vital to continuously test the oil to better understand condition. A lack of understanding of the gradual change in the transformer oil’s properties can lead to catastrophic failures, both physical and financial. The easiest and most common electrical tests to conduct on insulating oil to measure the dielectric properties is breakdown voltage testing, dissipation factor/power factor testing, and specific resistivity testing.

The BAUR DPA 75 C makes evaluating transformers and other dielectric fluid-filled equipment through proper insulated oil testing easier, more accurate, and more economical than ever before. Unique in the market due to its precision, functionality, lifetime of use, and value, the DPA 75 C is developed especially for use in laboratories as well as for portable field testing on-site. It provides clear, reliable, and reproducible measurement results. The DPA 75 C is particularly handy, easy to operate, and excellent under tough ambient conditions.

DPA 75 C Features:

• Fully automatic measurement of the dielectric strength of insulating oil up to 75 kV
• Integrated battery with long operation time out in the field (> 8 hours on full charge)
• Clear and reliable results through the latest measurement technology (“Real Breakdown Monitoring”)
• Repeatable breakdown measurement in mineral, silicone, and natural ester fluids
• Modern and robust design for laboratory or on-site testing
• Fully automatic measuring sequences from 18 programmed test standards and 10 user-programmable test sequences
• Oil-proof membrane keyboard, easy to read LCD display, and integrated printer
• Built-in sensor for temperature measurement of the insulating oil
• High quality glass test cells

The larger brother to the DPA 75 C is the DTA 100 C, designed for continuous operation in the laboratory.

DTA 100 C Features

• Fully automatic measurement of the dielectric strength of insulating oil up to 100 kV
• Repeatable breakdown measurement in mineral, silicone, and natural ester oils
• Extraordinarily powerful for continuous use in the laboratory
• Clear and reliable results through the latest measurement technology (“Real Breakdown Monitoring”)
• Fully automatic measuring sequences from 18 programmed test standards and 10 user-programmable test sequences
• Oil-proof membrane keyboard, easy to read LCD display, and integrated printer
• Built-in sensor for temperature measurement of the insulating oil
• High quality glass test cells
• EMC shield to prevent damage to IT infrastructure

The BAUR DTL C provides precise information for efficient oil management, and valuable findings in scientific research and development as well as providing extensive knowledge about the current state of insulating liquids in transformers. The DTL C combines the measurement of dissipation/power factor, specific resistance, and relative permittivity of dielectric insulating oils all in a single instrument.

DTL C Features

• Fully automatic measurement of tan delta/power factor, specific resistivity, and relative permittivity of insulating oils
• Maximum accuracy with tan delta measurement up to 1×10^-6
• Measurement of the specific resistance with both polarities up to 100 TΩm
• Measurement of the relative permittivity
• Excellent design for high efficiency and usability
• Latest, highly precise measurement technology for tests on mineral oils, silicone, and ester fluids
• Fast and precise induction heating of the test cell with accurate temperature control for a temperature independent result
• Direct temperature measurement by placing the sensor in the measurement electrode

Optimum Data Management Possibilities of all models (DPA 75 C, DTA 100 C, DTL C)

Proper archiving of the measurement results is essential for the analysis of insulating fluids. There are 3 different possibilities to archive the results:

1. Integrated printer for an immediate printout of the results.
2. ITS Lite Software: allows structured storage of measurement results in .pdf and/or .txt files on any PC/laptop that is connected to the unit via a USB cable.
3. Report Manager: allows automatic storage of measurement results in .pdf and/or .txt files on an external device that can be exported at a later time using a USB stick.