Specification of on load switch for transformer

Specification of on load switch for transformerFunctional Features

The on load switch of the transformer has functions such as displaying, analyzing, storing, and printing the measured data. Solved the problem of outdated measurement methods and lack of testing methods for on load tap changers in power transformers. Timely diagnosis of potential faults in on load tap changers during preventive testing of power equipment and transformer overhaul is of great significance for improving the reliability of power system operation. The on load switch of the transformer has functions such as displaying, analyzing, storing, and printing the measured data. Solved the problem of outdated measurement methods and lack of testing methods for on load tap changers in power transformers. Timely diagnosis of potential faults in on load tap changers during preventive testing of power equipment and transformer overhaul is of great significance for improving the reliability of power system operation.

——High precision standard measurement
This instrument is designed to fully meet the high voltage testing equipment standards of the power industry in the People's Republic of China, with general technical specifications DL/T846.8-2004. It uses a high-speed digital signal processor DSP and a 12 bit high-resolution A/D converter to achieve high-precision standard measurement.

——Optical oscilloscope function
The instrument is divided into three channels and can simultaneously record phases A, B, and C. The instrument can automatically capture and display the transition resistance and time jump process during the transition process. It can work normally in complex environments and is far superior to optical oscilloscopes in terms of accuracy and intelligence.

——Strong comprehensive ability
Comprehensive measurement of various parameters of on load tap changers can be achieved within one instrument. Whether there are breakpoints, transition waveforms, transition times, transition resistances, three-phase synchronicity, etc. during the entire process of switch selection and switching. Combined with various functional buttons, it is possible to further analyze the time and resistance values of each time period in the waveform in detail.

Specification of on load switch for transformerothers

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.