The voltage transformer double frequency AC withstand voltage tester is a device used for voltage transformer double frequency AC withstand voltage test.

From the relationship of induced potential, it can be seen that in order to apply a test voltage greater than the rated voltage without saturating the core, the power supply frequency can be increased, and a power generator greater than the double frequency must be used. It is simple to operate, reliable in performance, and can well meet the needs of transformer and transformer induced withstand voltage.

The voltage transformer double frequency AC withstand voltage tester is used for test products such as power transformers and voltage transformers. In addition to the external construction frequency high voltage test on the main insulation of the fully insulated transformer, the longitudinal insulation of the transformer and the main insulation of the semi-insulated transformer are also subjected to induced high voltage tests.

According to national test standards, the induced test voltage of power transformers and voltage transformers is considered to be approximately 2-3 times the maximum working phase voltage. As we all know, at the rated frequency and rated voltage of the transformer, the core is close to saturation. If a test voltage greater than the rated voltage is applied to both ends of the transformer winding by a power frequency power supply, the no-load excitation current will increase sharply to an unacceptable level.

Transformer AC withstand voltage test, the following are the test steps summarized by Shanghai DEMIKS Electric Power Test Engineer:

1. It should be carried out at 80% of the factory test voltage:

2. When the electromagnetic voltage transformer (including the electromagnetic unit of the capacitive voltage transformer) encounters a high core magnetic density, it is advisable to carry out the induction withstand voltage test according to the following provisions;

1) The induction withstand voltage test voltage should be 80% of the factory test voltage.

2) The test power supply frequency and test voltage time shall refer to the provisions of Article 7.0.13, paragraph 4.

3) Before and after the induction withstand voltage test, the no-load current measurement at the rated voltage shall be carried out once, and there should be no significant difference between the two measured values;

4) For oil-immersed transformers with voltage levels of 66kV and above, the chromatographic analysis of the insulating oil shall be carried out once before and after the induction withstand voltage test, and there should be no significant difference between the two measured values

5) During the induction withstand voltage test, the voltage value should be measured at the high voltage end.

6) When the intermediate voltage transformer of the capacitive voltage transformer is subjected to the induction withstand voltage test, the voltage divider capacitor should be disassembled. If the product cannot be disassembled on site due to structural reasons, the induction withstand voltage test may not be performed.

3. SF6 gas insulated transformers with voltage levels above 220kV (especially transformers with voltage levels of 500kV) should be subjected to AC withstand voltage test after installation;

4. The power frequency withstand voltage test voltage standard between secondary windings and to the shell should be 2kV;

5. The power frequency withstand voltage test voltage standard of the current transformer end screen and the voltage transformer grounding terminal (N) to the ground with voltage levels of 110kV and above should be 3kV.

The main products of Shanghai Demiks Power Technology Co., Ltd. include: "Series resonance test equipment, partial discharge test system, high voltage insulation withstand voltage, transformer test, circuit breaker test, relay protection, secondary circuit test, cable line test, lightning arrester insulator tester, SF6 test, oil test, DC system battery test, reactive power compensation generator detection, ground insulation resistance test, power metering test, etc." More than 200 products in 20 categories".

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