Operating principles of power transformers Rated operating modes of power transformers

Power transformers are important devices that convert alternating current energy from one voltage level to another. In the power system, transformers play important roles in power transmission, voltage regulation, and power load distribution. This article will introduce in detail the operating principles and rated operation methods of power transformers.

1. Operating principles of power transformers

Power transformers rely on the principle of electromagnetic induction to convert electrical energy. Its operating principles can be summarized into the following aspects:

1. Magnetic induction lines

The core part of the power transformer is the iron core, which is formed by winding coils on the iron core Primary and secondary windings. When alternating current passes through the primary winding, the magnetic flux coil it generates is transferred to the secondary winding through the iron core, and then an electromotive force is induced in the secondary winding and output through the output port.

2. Magnetic induction intensity

Magnetic induction intensity refers to the number of magnetic induction lines per unit area in the iron core, represented by B, and the unit is Tesla(T). The magnitude of the magnetic induction intensity is related to the current passing through the main winding. According to Ampere's law, the greater the current, the greater the magnetic induction intensity.

3. Transformer Law

Transformer Law is one of the basic principles of power transformers. According to the transformer law, the input power of the transformer is equal to the output power, that is, the voltage and current in the primary and secondary windings satisfy the following formula: primary winding voltage × primary winding current = secondary winding voltage × secondary winding current.

4. Transformer turns ratio

The turns ratio of a transformer refers to the voltage ratio between the primary winding and the secondary winding. The transformation ratio determines the input and output voltage levels of the transformer. According to the transformation ratio relationship of the transformer, power conversion of different voltage levels can be achieved without changing the frequency.

2. Rated operating mode of power transformer

The rated operating mode of power transformer refers to the power and voltage level at which the transformer can continue to operate under standard working conditions. According to the rated operation mode, transformers can be divided into the following categories:

1. Rated capacity

The rated capacity of the transformer refers to the active power that the transformer can continuously supply, usually in kilowatts (KVA) is the unit. The rated capacity determines the load the transformer can carry.

2. Rated voltage

Rated voltage refers to the rated voltage of the primary and secondary windings of the transformer. During operation, the voltage of the primary winding and secondary winding of the transformer is generally an integral multiple or a fractional multiple of the rated voltage, forming different connection configurations.

3. Rated current

Rated current refers to the maximum current that the transformer can flow at rated voltage. The rated current determines the current load the transformer can carry.

4. Rated frequency

The rated frequency refers to the AC frequency considered when designing the transformer. In most countries and regions, the standard frequency of the power system is 50Hz or 60Hz, and the rated frequency of the transformer is consistent with the standard frequency of the power system.

According to different rated operating modes, transformers can meet different needs, such as power transmission, voltage regulation, electrical energy load distribution, etc.

Power transformer is a device that uses the principle of electromagnetic induction to achieve voltage conversion. Its operating principle is that the current in the primary winding generates a magnetic field in the iron core, thereby inducing the electromotive force in the secondary winding.

According to the transformer law, the input power of a transformer is equal to the output power. According to the rated operation mode, the transformer can meet different load requirements, such as rated capacity, rated voltage, rated current, rated frequency, etc. Power transformers play an important role in the power system, providing strong support for power transmission and adjustment.