Transformer load test purpose

In a transformer load test, the transformer side is short-circuited at the winding end and the other side is supplied with the rated current at the rated frequency. At this point, the rated current flows into the windings on both sides, creating leakage magnetism. In addition to the resistance loss caused by the rated current in the winding, the loss caused by the leakage flux in the winding and the construction is called the loss in the neighborhood, and the load loss is collectively referred to as the loss measured in the load test. The voltage applied to a short-circuited winding to produce the rated current in a load test is the impedance voltage, usually expressed as a percentage of the rated voltage.

Regardless of the size of the transformer, load losses account for most of the total losses. By analyzing the load losses, defects in the construction and manufacturing of the transformer were identified. Impedance voltage is one of the important conditions for parallel operation of transformers.

　　1。Standards and requirements related to load testing

　　2。Impedance voltage and load loss must meet the requirements of gb1094.1

　　3。Load testing is performed by the main coupling

　　4。The bypass transformer is supplied with the rated current from the side of the test object and short-circuited on the other side, and is measured only once. 3-winding transformers must be carried out between pairs of windings, and the other windings must be open-circuited.