In this article we will know a little better the equipment for measurement dielectric strength of insulating oil. The Dielectrotest is a fully automatic dielectric oil analyzer, used to determine the breaking voltage of the insulating liquid. The equipment is designed to be used in the laboratory or in the field in commissioning and maintenance tasks since it serves to test the electrical insulation capacity and the voltage test of insulating oils in transformers.
The test is very simple, but before starting the test of dielectric strength, the type of electrode and the distance between electrodes should be selected. After placing the glass container with the oil sample in the test chamber, the cover is closed, this cover is equipped for safety with a lock that disconnects the high voltage if it is opened during the test.
When the test starts, the oil temperature and the user identification number are entered in the equipment for the test report (if the user does not enter it, each serial sample is assigned to each oil sample). The equipment has stored the most common test sequences defined in the different international standards, in addition the user can define and store up to 10 test sequences with total freedom.
Once the test has finished, a detailed report is printed that includes information on the date and time of the test, sample number, individual rupture values, means and standard deviation. The last 20 tests are stored in the internal memory and can be retrieved and printed. In addition, the results can be downloaded to a computer using the PrintCom software that stores the results in configurable Excel format.
Technical characteristics:
- The test voltage depends on the model: Model 60A-2 60kV, Model 80-A 80kV, Model 100A-2 100kV
- Power: 110,230,240 V / 50Hz or 60Hz
- Alimentación: 110,230,240 V / 50Hz o 60Hz
- Maximum power consumption 900VA
- Voltage measurement: real RMS, resolution 0.1kV, precision + -1Kv
- Fault monitoring: detection of insulating liquids with insulation resistance below 30MOhms
- Test standards: IEC 156/95, VDE 370/96, BS 5874/80, UTE C 27-221 / 74, UNE 21309/89, NEN 10156, SEV 3141/69, CEI 10-l / 73, ASTM D1816 / 90, ASTM D877 / 90, JIS 2101-82, JIS Silicon 2101/82, selectable from the menu, 10 additional, fully programmable user test sequences.
- Magnetic agitator with teflon rod.
Once the analyzer is turned on by means of the key switch, you will see the following screen for a moment. While viewing this screen, an automatic examination of the indicator lights will be performed.
El menú principal siempre aparece después de encender el analizador o después de finalizar una prueba.
Below is the initial process of an oil test:
- Start the test
- Select test standards / select or define user standards
- Measure and enter the room temperature (without Expert Mode on)
- Select the container with its respective electrodes (without Expert Mode on) Depending on the chosen standard, it is possible to use two different types of electrodes.
- Adjust the distance of the electrodes (without Expert Mode on) The electrodes must be adjusted on both sides by means of the adjustment screw, this is very important in order to center the position of the electrodes in the container
- Fill the previously cleaned container with oil (for cleaning the container, use alcohol.The oil to be measured should be poured slowly avoiding air bubbles.The oil level should be approximately 10 mm above the upper edge of the electrodes)
- Insert the container in the analyzer
- Close the cover
- Enter the test number (without Expert Mode on))
- Start the test
- If necessary, print or store the results
The sequence of the test generally consists of individual cutting steps that are happening one after the other. The high-voltage connection is preceded by a certain time. At this time, the voltage increases continuously until one of the cuts occurs. If one of the cuts occurs, the voltage is interrupted quickly. The agitator can remain to stir the oil. The entire process is defined in the standards. Test times, agitator activity, etc. they are automatic as defined in the standards. The process can not be influenced. If different processes are required, it will be necessary to generate specific user programs. The following graphic shows the most basic form of a test sequence.
With the dielectric oil analysis equipment, different tests can be performed. The most basic user program is manual operation, where the voltage consists of a single test sequence in which the voltage is continuously increased until the cut happens. Another test is the voltage resistance test, where the voltage is increased to a configurable level. Then the voltage remains circulating for a time also configurable until the end of the test. If there is any cut during the test, it is interrupted immediately.
Ultimately the Dielectrotest (also called Chispometer or rupture voltage meter), is a fully automatic test equipment to measure the breaking voltage of insulating liquid, fully automatic and configurable by the user, very easy to use, valid for both laboratory as for its use in the field.
http://www.amperis.com/en/products/transformers-testing/dielectrotest/