Transformer On-Load Tap Changer Tester Quotation
Darui Electric recommends for you:
Related Description
1.Transformer On-Load Tap Changer TesterIn actual measurement, the measured waveform is often worse than the theoretical waveform, especially when measuring with windings. This is because the oscillation signal caused by the inductance and capacitance parameters of the transformer winding during measurement, as well as the mechanical vibration of the tap changer, causes some fluctuations in the measured waveform. This situation is unavoidable in actual testing. Some new switches may show insulation characteristics of the protective oil film on the contact points at low voltage; and for switches with long service life and oxidized contact points, the waveform may be affected during testing, which is also normal. You can switch the tap changer several times on this position to thin the oxide layer, increase the contact area, and then use the instrument for testing, which may avoid this phenomenon.
2. Another phenomenon is over-range testing. For example, if the transition resistance of the tested switch is greater than 9Ω, and the range is selected as 9Ω for measurement, the result will show a waveform as shown in Figure 21. At this time, the transition resistance indicated by cursor 1 may be normal, while the transition resistance indicated by cursor 2 displays as 50.0Ω, which is due to over-range. Simply change the range to 30Ω and test again. It is also possible that the middle part of the transition process is a flat line at 50.0Ω, also caused by over-range, and then just change the range to 30Ω.
3. When performing no-winding measurement, without the influence of distributed parameters of the transformer winding, the waveform will be closer to the theoretical waveform. When the measured waveform curve is not straight, it is mostly due to mechanical transmission reasons, not a problem with the switch or instrument testing. If there is a breakpoint and the waveform at the breakpoint returns to the bottom, it should be treated with caution.
4. Sometimes there is an instantaneous breakpoint during switch switching, and the waveform is compressed into an approximately straight line. This situation is caused by the processing of this instrument. When moving cursor 2 to read points on the three-phase waveform curve, you can still see the resistance changes during each switching period, but it is best to retest in this case. When there is an abnormal downward jump point in the waveform and the duration is more than 2ms, check the resistance value at that point. If the resistance value exceeds 50Ω, there may be poor contact or looseness. In this case, repeated tests should be performed to make a judgment.
1. Three-phase constant current source charging, charging current: 3A/1A gear; 0.6A/0.2A gear;
2. Maximum port voltage: 24V;
3. Maximum transition resistance range: 100Ω;
4. Transition resistance measurement range: 1A gear: 0.4Ω～20Ω 0.2A gear: 10Ω～100Ω;
5. Waveform recording time length: 300ms;
6. Sampling rate: 30k;
7. Time resolution: 0.1ms;
8. Resistance resolution: 0.1Ω;
9. Accuracy: Transition resistance: ±5% reading ±0.1Ω Transition time: ±0.5% reading ±0.2mS;
10. Operating temperature: -10～40℃ Operating relative humidity: <85%RH.
