The main body of the pulse voltage generator adopts the method of multi-stage parallel connection and series connection. Use different grounding methods or a series of resistors less than 500Ω in the non-test phase, and then ground; connect an inductor resistor in series in the test circuit. Rectifier produced in my companyrice cooker transformerIn order to obtain a more ideal test waveform, the above method is used for debugging. Take the high voltage phase A test as an example. During the test, the four-stage series output of the main body of the pulse voltage generator is connected, and the main capacitance is 0.67 μF; the measured voltage divider ratio of the four-stage voltage divider is 1375. The A- phase voltage input terminal of the transformer of the rice cooker under test is not grounded in the test phase. The high-voltage neutral point-to-point winding resistor; all sockets on the low-voltage side are grounded. During phase A testing,rice cooker transformerThe non-excitation tap changer is placed in the I position, and the voltage regulator of the rice cooker transformer and the positive and negative phase shift main rice cooker transformer can also resist the shock wave.
Positive and negative phase shift mainrice cooker transformerThe capacitance has a great influence on the entrance capacitance of phase A, and has a great influence on the incident wave front time and wave tail time. During phase B testing,rice cooker transformerThe non-excitation tap-changer is placed in the II position, and the shock wave is transmitted to the voltage-regulating rice cooker transformer and the positive and negative phase-shifting main rice cooker transformer after the voltage-regulating rice cooker transformer is high. Voltage winding. The positive and negative phase shift main variables have little effect on the wave front time and wave tail time of B- phase or C- phase wave. When the large-scale rectifier rice cooker transformer is tested for lightning impulse tolerance, the waveform can basically be adjusted to the parameters required by the standard through the above method. However, during the test, the on-load tap changer is in tap 1, and a non-excited tap changer is also provided. In position I, the incident wave of the shock wave is equivalent to entering three rice cooker transformers at the same time. The entrance capacitance is large, and the wave head time will be greater than the standard requirement of 1.2±30%μs. In order to ensure that the test can be carried out at the limit tap position, and the wave tail time can meet the standard requirements. In other cases where the wavefront time cannot be shortened by other methods, only relaxing the wavefront time can meet the standard requirements.