What is furan content in transformer oil?
What is furan content in transformer oil?
The Total Furan content of the Transformer was monitored since then. It increased to 1404 ppb within the next 4 months. In Feb 2008, when the Test was carried, the Furan content had increased to 8530 ppb. The Furan content in the Transformer oil had reached 12739 ppb by April 2008.
What is DP test in transformer?
The degree of polymerization (DP) test is another means of assessing insulation aging. This test is performed on paper samples. The DP test provides an estimate of the average polymer size of the cellulose molecules in materials such as paper and pressboard. Generally, paper in new transformers has a DP of about 1000.
What is DGA test of transformer oil?
Dissolved gas analysis (DGA) is the study of dissolved gases in transformer oil. It is also referred to as a DGA test. Whenever a transformer undergoes abnormal thermal and electrical stresses, certain gases are produced due to the decomposition of the transformer oil.
What is degree of polymerization in transformer insulating oil?
The degree of polymerization (DP) is a direct technique applied to assess the condition of insulating paper in power transformer as stated in IEC 60450 [14]. DP value reveals a strong correlation between the insulation paper deterioration and formation of aging products.
What is tan delta test in transformer?
A Tan Delta test is performed by applying an ac voltage to a test cell of known gap, measuring the total current flow through the oil, and separating and comparing the reactive and resistance portions of the current passing through the oil.
What is sludge formation in transformer oil?
Oil Deterioration in Transformers The oil used in the transformer acts as a coolant as well as an insulator. During the continuous operation of the transformer, the moisture in the oil as well as the oxidation process leads to the formation of the semi solid hydrocarbon termed as sludge.
What is dwell time in NDT?
Penetrant dwell time is the total time that the penetrant is in contact with the part surface. The dwell time is important because it allows the penetrant the time necessary to seep or be drawn into a defect. Dwell times are usually recommended by the penetrant producers or required by the specification being followed.
What is BDV value of transformer oil?
A typical value of BDV Test result for 220 / 6.6 kV Transformer oil is 65 kV and moisture content should be less than 10 ppm. BDV is an important and popular test of transformer oil, as it is the primary indicator of the health of oil and it can be easily carried out at the site.
Why is DGA important?
DGA is beneficial to a preventive maintenance program. The collection and analysis of gases in an oil-insulated transformer was discussed as early as 1928. As of 2018, many years of empirical and theoretical study have gone into the analysis of transformer fault gases.
How do you determine the degree of polymerization?
Divide the molecular weight of the polymer by the molecular weight of the monomer unit to calculate the degree of polymerization. If the molecular mass of tetrafluoroethylene is 120,000, its degree of polymerization is 120,000 / 100 = 1,200.
What is UST and GST?
GST stands for grounded specimen test while UST stands for ungrounded specimen test. Within the two groups the test set can be operated in seven test modes as summarized in Table 1.1. Measurements are always made between the high-voltage lead and the lead/ connection in the measure column.
What is the safe limit of tan delta?
4. Capacitive Voltage
| Sr. No. | Equipment / test data | Permissible limits |
|---|---|---|
| A) | Tan Delta | 0.007* at 20 Deg. C |
| B) | Capacitance | Within +10%/-5% of the rated value |
| C | Contact resistance of terminal connector | 10 M-Ohm per connector |
| D) | IR Value | IR Value |
What is crackle test of transformer oil?
The crackle test is a standard laboratory test to detect the presence of water in lubricating oil. A drop of oil is placed on a hotplate that has been heated to approximately 400° F. The sample then bubbles, spits, crackles or pops when moisture is present.
How do you remove sludge from a transformer?
Once sludge occurs, the internal parts of the transformer require flushing with hot oil to remove the sediment. If not rinsed down, the core and coil assembly will hold the acids which will leach back into the oil over time. This will cause the re-deterioration of the oil to be accelerated.
What is principal of DPT?
Principle: DPT is based on the principles of CAPILLARY ACTION. By virtue of which, liquid tends to flow or seep into any narrow opening, even against external forces like gravity. This phenomenon occurs due to molecular attraction.
What is DPT in mechanical?
DPT – Dew point temperature tDP – It is the temperature at which air water vapour mixture starts to condense.
What is size of test cell in BDV?
Machine Technical Specification
| Input Supply | 220V±10% Volts AC, 50 Hz, single phase. |
|---|---|
| Test cell with Electrodes | Type ‘TC-2’: 36 mm mushroom electrodes. Type ‘TC-3’: 25 mm flat disc electrodes. Type ‘TC-1’: 13 mm round electrodes. |
| Gap Gauge | 2.5 mm |
| Printer | Built in printer for printing results on plain paper. |
What is PPM test in transformer?
PPM stands for Parts Per Million. It is used to measure the weight of moisture divided by the value of oil. The moisture content in oil lowers the insulating system dielectric strength that permits flashover to harm a transformer. For example, for mineral oil, a generally accepted maximum moisture content is 35 ppm.
What is the BDV of transformer oil?
As per IEC, the minimum BDV of transformer oil should be 30 KV as per transformer oil BDV test standard. The transformer oil is used in the transformer for insulation as well as for cooling purpose. The different insulating materials have different dielectric strength.
