What faults are prone to occur in the variable ratio group tester?

The transformer ratio group tester is a test item that must be carried out after the handover and overhaul of transformers. The main purposes of making a variable ratio group tester are as follows:

① Check if the transformation ratio matches the nameplate to ensure correct voltage transformation.

② Check if the voltage tap changer indication is correct.

③ Checking the transformer ratio, that is, checking the turn ratio of each winding, can determine whether there is a turn to turn short circuit in the transformer.

④ Measure the imbalance degree of the transformation ratio of the three-phase transformer itself and determine the size of the zero sequence component.

⑤ Obtain accurate transformer ratios to determine whether transformers can operate in parallel.

When the difference in no-load voltage on the secondary side of two transformers operating in parallel is 1% of the rated voltage, the circulating current in the windings of the two transformers will reach about 10% of the rated current, which will increase the loss of the transformer and occupy the capacity of the transformer. Therefore, the difference in ratio should be limited to a certain range.

Common problems encountered in the use of variable ratio group testers

① When testing, connect the high and low voltage test wires in reverse, which can damage the instrument in common transformer ratio testers. In some new testers, protective devices have been installed, which can cause the fuse of the test circuit to blow when the test wire is reversed.

② The test value does not match the calculated value, and the wiring group does not match the nameplate wiring group. This may be due to damage to the instrument or a problem with the transformer.

③ Testing precautions: The wire clamp must be reliably clamped to prevent it from falling during the testing process. In previous tests, it was found that the wire clamp fell during testing, which in turn caused damage to the instrument.

The ZC-203AW fully automatic transformer ratio group tester is mainly used to supervise the quality of transformer products during delivery and use, to prevent inter turn short circuits, open circuits, connection errors, internal faults or contact faults of voltage regulating switches. The instrument is easy to operate, has complete functions, stable and reliable data, and has fast testing speed. It meets the needs of various large, medium, and small transformer ratio tests and is an ideal testing instrument for the power industry department.

Kvtester Electronics Technology Co.,Ltd. is a high-tech enterprise specializing in power testing, testing, research and development, production, and sales of testing equipment. It has been engaged in the electrical testing industry for many years, and its products are of high quality. We welcome customers to come and purchase.