How transformers work

(1) Normal operation mode: Operation at or below rated parameters, long-term operation is allowed;
(2) Normal overload operation mode: Operation when the load exceeds the allowable value. On the premise that the insulation and life are not affected, it is allowed to operate for a certain period of time (determined by the upper oil temperature before overload);
(3) Accident overload operation mode: When an accident occurs in the power system, in order to ensure the reliability of power supply,
the transformer allows short-term overload capability
Allowable temperature and temperature rise of the transformer: The allowable temperature of Class A insulation material is 105°C. In order to prevent the insulation and life from being affected, it is stipulated that the upper oil temperature of the transformer shall not exceed 95°C. In normal operation, in order to prevent the oil from being oxidized too quickly, the upper oil temperature shall not exceed 85°C. The temperature rise is the difference with the ambient air temperature.
Allowable voltage fluctuation: If the fluctuation of the power supply voltage does not exceed ±5%, the transformer can carry the rated load regardless of the voltage tap position.
Transformer voltage regulation: Transformer voltage regulation is achieved by changing the number of turns of the winding. Generally, the no-load adjustment range is within 5%, and the loaded adjustment range can reach 30%.