A technician from our company went to a transformer substation in Zhejiang and performed a transformer with a rated voltage of 110/10.5kV, a rated capacity of 40000kVA, a high-voltage side current of 210A, an impedance voltage of 19.76%, and a wiring group of Ynd11. Use CT3600 transformer short-circuit impedance tester to conduct low-voltage short-circuit impedance test. The temperature of the transformer is 45℃. The test data is shown in the table.
Transformer short-circuit test data table:
Calculate according to the test data in the table:
⑴ First convert the test voltage of each phase to the impedance voltage under the rated condition
(2) Substitute UKAB, UKBC, and UKCA into the formula:
(3) The impedance voltage measured by calculation is 19.45%, which is less than ±3% compared with the nameplate impedance voltage. Therefore, the impedance voltage of the transformer meets the requirements of the test standard, "transformer short-circuit impedance deviation ±10%".