Transformer on load switch testing device

Transformer on load switch testing deviceMain technical indicators

1. Three independent test power supplies, with a large output power supply of 1A;
2. Set the sampling rate of the instrument to 10~20KHZ;
Single waveform large storage time of 6.4 seconds.
4. Transition resistance measurement range: Y/△ type transformer ≤ 40 Ω, Y type transformer ≤ 20 Ω.
5. Measurement accuracy: △ ≤ 10%
Measurement synchronicity error: 0.2ms.
7. Display: 240 × 128T, T6963 controller;
⒏ Printer: MP-40-8 panel type front paper exchange printer;
9. Processing section:
80C320 high-speed 8-bit microprocessor. Program memory 32K;
Maintain 512K bytes of data storage during power failure;
High speed A/D converter with a high sampling rate of up to 400KHZ;
Power supply 220V ± 10%, power ≤ 200W.
Size: 410mm × 320mm.
Weight ≤ 7kg
Random attachments: 4 test wires, 4 crocodile test pliers

Transformer on load switch testing deviceadvantage:

1. Test the YO Y △ transformer and display the resistance value directly without conversion;
2. Humanized data analysis can automatically identify faults in the middle of the waveform and mark them;
3. The waveform display automatically adjusts the resistance and time amplitude based on the sampled data;
4. △ - type transformers can display three-phase synchronicity;
5. It can be tested with or without windings;
6. Four terminal wiring method, providing high-precision resistance measurement without the need for wire compensation;
7. Continuous testing can be conducted during testing to save time on transformer power outages;
8. The instrument is controlled by a small computer, equipped with an 800 × 480 color LCD touch screen and a high-speed printer;
9. The instrument can automatically save 100 sets of data internally.

1. In actual measurement, the measured waveform is often worse than the theoretical waveform, especially when there is winding measurement. This is because the oscillation signals caused by the inductance and capacitance parameters of the transformer winding, as well as the mechanical vibration of the tap changer during measurement, result in some fluctuations in the measured waveform, which cannot be avoided in actual testing. Some new switches exhibit insulation at low voltages due to the protective oil film on the switch contact points; And for switches with a long service life and oxidation phenomenon at the switch contact points, the waveform may appear during testing, which is also a normal phenomenon. You can switch the switch several times on this level to make the oxide layer thinner, increase the contact area, and then use the instrument for testing, which may avoid this phenomenon.

2. Another phenomenon is the over range test, such as when the transition resistance of the test switch is greater than 9 Ω and the measurement range is selected as 9 Ω, the waveform shown in Figure 21 will appear. At this point, the transition resistance at the location indicated by cursor 1 may be normal, while the transition resistance at the location indicated by cursor 2 is displayed as 50.0 Ω. This is due to overtravel, and simply change the range to 30 Ω before testing. It is also possible that the intermediate process of the transition is a straight line with a resistance of 50.0 Ω, which is beyond the range. Therefore, it is only necessary to change the range to 30 Ω.

3. When conducting measurements without windings and without the influence of distribution parameters of transformer windings, the waveform will be closer to the theoretical waveform. When the waveform curve measured by the user is not straight, it is mostly due to mechanical transmission reasons, not problems with switch or instrument testing. If a breakpoint occurs and the waveform returns to the bottom at the breakpoint, caution should be exercised.

4. Sometimes there is a momentary breakpoint when switching the switch, 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 the points of the three-phase waveform curve, the changes in resistance during each switching period can also be seen, but this situation needs to be retested. When there is an abnormal jump point in the waveform and the duration is more than 2ms, the resistance value at that point should be checked. If the resistance value exceeds 50 Ω, there may be poor contact or loose parts. At this time, multiple tests should be repeated to make a judgment.