Power Transmission Transformer Technical Parameters

Under the specified use environment and operating conditions of the power transmission transformer, the main technical data are generally marked on the nameplate of the power transmission transformer. It mainly includes: rated capacity, rated voltage and its tap, rated frequency, winding connection group, rated performance data (impedance voltage, no-load current, no-load loss and load loss) and total weight.

A. Rated capacity (kVA): The capacity that can be delivered during continuous operation at rated voltage and rated current.

B. Rated voltage (kV): The working voltage that the power transmission transformer can withstand when it runs for a long time. In order to meet the needs of grid voltage changes, the high-voltage side of the transformer has taps, and the output voltage of the low-voltage side is adjusted by adjusting the number of turns of the high-voltage winding.

C. Rated current (A): The current that the transformer is allowed to pass through for a long time under the rated capacity.

D. No-load loss (kW): When the rated voltage at the rated frequency is applied to the terminal of one winding and the other windings are open-circuited, the active power drawn. It is related to the performance of the core silicon steel sheet, the manufacturing process, and the applied voltage.

E. No-load current (%): When the secondary side of the power transmission transformer is no-loaded at the rated voltage, the current passing through the primary winding is generally expressed as a percentage of the rated current.

F. Load loss (kW): short-circuit the secondary winding of the power transmission transformer, and pass the rated current at the rated tap position of the primary winding. At this time, the power consumed by the transformer.

G. Impedance voltage (%): short-circuit the secondary winding of the transformer, and slowly increase the voltage in the primary winding. When the short-circuit current of the secondary winding is equal to the rated value, the voltage applied to the primary side at this time. Generally, the rated voltage expressed as a percentage.

H. Number of phases and frequency: The three-phase starts with S, and the single-phase starts with D. The Chinese national standard frequency f is 50Hz. There are 60Hz countries abroad (such as the United States).

I. Temperature rise and cooling: The temperature difference between the transformer winding or upper oil temperature and the surrounding environment of the transformer is called the temperature rise of the winding or upper oil surface. The temperature rise limit of the oil-immersed transformer winding is 65K, and the temperature rise of the oil surface is 55K. There are also many cooling methods: oil-immersed natural cooling, forced air cooling, water cooling, tube type, sheet type, etc.

J. Insulation level: There are insulation level standards. The expression method of insulation level is as follows: the insulation level of a transformer with a high-voltage rated voltage of 35kV and a low-voltage rated voltage of 10kV is expressed as LI200AC85/LI75AC35, where LI200 means that the high-voltage lightning impulse withstand voltage of the transformer is 200kV, and the power frequency withstand voltage It is 85kV, the low-voltage lightning impulse withstand voltage is 75kV, and the power frequency withstand voltage is 35kV.

K. Label of the connection group: According to the phase relationship between the primary and secondary windings of the power transmission transformer, the transformer windings are connected into various combinations, which are called the connection group of the winding.