By hvhipot 
The high-voltage test transformers under HV Hipot Electric Co., Ltd. Power can help many power workers conduct various power tests more conveniently.
Definition of Testing Transformer
Transformer capacity and characteristic testing is a professional test. There are many projects for setting up sections and testing methods.
1. Click
In a transformer with a top winding, each tap in the winding represents a fixed number of turns in the tap, which also means a fixed number of turns between the tap winding and other constant windings
2. Main attack
The tap corresponds to the rated parameters. Note: The load/no-load loss and no-load current data are the data of the transformer at the main tap (excluding other specified taps)
3. On load tap changer charger
It is a device used to change the tap position of transformer windings during excitation or no-load operation.
4. Offline tap changer charger
It is a device that changes the tap position of the transformer winding when operating without excitation.
5. No load loss (commonly known as iron loss, iron loss)
The rated voltage (tap voltage) at rated frequency is applied to the terminals of one winding, and when the other winding is open circuited, it is the active power.
6. No load current
When the rated voltage (tap voltage) at rated frequency is applied to one winding terminal and the other windings are open circuited, it is the root mean square of the current.
Note 1: For three-phase transformers, it is the average value of the three-phase terminal current.
Note 2: It is generally displayed as a percentage of current. For multi winding transformers, use the winding with the maximum rated capacity as the reference.
7. Load loss (short-circuit loss/copper loss)
It is the active power in a pair of windings when the rated current flows through the line terminal and short circuits the other terminal at the rated frequency and reference temperature. If there are other windings, please open them.
Note 1: The dual winding of a transformer only has one pair of windings and one load loss value.
For multi winding transformers, there are multiple logarithmic and load loss values.
Note 2: When determining the capacity of two windings, the rated current of the winding with the lower rated capacity should be used as the reference and designated as the reference capacity.
8. Total loss
The sum of load loss and no-load loss.
9. Short circuit impedance
Usually, short-circuit impedance is the impedance of the winding.
At rated frequency and reference temperature, the equivalent series impedance of a pair of windings between the winding terminals is
Z=R+jX (Ω). Now, the other terminal needs to be short circuited. If there are other windings, an open circuit is required.