The on-line oil purifier of transformer on load tap changer is composed of oil pump, filter, control cabinet, instrument panel, valve and pipeline system. The on-line oil purifier of the on load tap changer of the transformer is used for the bypass circulating filtration of the on load tap changer of the transformer. It can automatically send the insulating oil to be purified to the filtration system through the oil pump (suction), and return the filtered qualified insulating oil to the independent oil chamber of the on load tap changer. The filtered particulate impurities and water remain in the filter, To ensure that the insulation performance index of the insulating oil in the independent oil chamber of the on load tap changer meets the standard in the operation of the on load tap changer. When the working pressure increases to the preset value due to the remaining impurity particles and moisture, the device will automatically send the signal of replacing the filter element and stopping the work.
Main technical indexes of on-line oil purifier of transformer on load tap changer:
1. Filtration accuracy and micro water content in filtered oil: filtration accuracy ≤ 1 μ M, the micro water content in the filtered oil is ≤ 30mg / L;, Filtering accuracy ≤ 3 μ M, the micro water content in the filtered oil is ≤ 25mg / L; Filtering accuracy ≤ 9 μ M, the micro water content in the filtered oil is ≤ 10mg / L.
2. Filtration ratio: β 1 ≥ 1000 (filtration efficiency ≥ 99.9%)
3. Filter cleanliness: it is required to meet the chromaticity below No. 7; Or meet nas1638 Standard Level 7 or below. Both chromaticity and color grade refer to the degree of impurity particles contained in the oil, which is expressed by the number of chromaticity and the grade of color grade. Since nas1638 Standard cannot be directly observed and judged by eyes, it is recommended to use the judgment method of chromaticity. (see Appendix A "cleanliness, appearance chroma and transparency of insulating oil" for specific description of chroma)
4. Insulation strength of filtered oil: ≥ 40kV
5. Working flow: ≥ 10L / min, the maximum flow shall not cause misoperation of oil flow relay.
6. Ultimate working pressure: ≤ 0.35Mpa
7. Working noise: ≤ 65dB (a) when not greater than the limit working pressure (slightly greater than the transformer noise is allowed)
8. Maximum allowable continuous oil purifiering time: 72h.
9. Maximum allowable oil purifiering temperature: 95 ℃.
Main electrical performance of on-line oil purifier of transformer on load tap changer:
1. Rated power supply: power frequency three-phase 380V ± 10%
2. Trouble free working time: accumulated working time, 20000h (5 hours per day, about 10 years)
3. Insulation resistance of electrical circuit: 500V megger ≥ 20 Μ Ω
4. The electrical circuit shall be able to withstand the withstand voltage test of power frequency 1500V / 1min without flashover and breakdown.
5. The electrical circuit shall be equipped with a phase sequence control switch to ensure the steering of the oil pump.
6. The electrical circuit shall have an automatic air switch that can feel the circuit fault and automatically isolate the power supply.
7. If the oil system has a heater, it shall have automatic temperature control to keep the oil temperature (including water filter element) not lower than 5 ℃.