What is related to transformer leakage inductance? How much should the leakage inductance of a transformer generally not exceed?

1. Introduction

Transformer is one of the most common devices in the power system. Its function is to transform high voltage into low voltage to meet various electricity needs such as people's daily life and industrial production. However, leakage inductance is an inevitable phenomenon during the operation of the transformer. It refers to the loss of magnetic flux caused by the magnetic field penetrating the air gap between the windings of the transformer. Leakage inductance has a great impact on the electrical performance and energy efficiency of the transformer. This article will discuss in detail issues related to transformer leakage inductance.

2. Definition of leakage inductance

Leakage inductance refers to the magnetic flux loss caused by the incomplete magnetic circuit when the magnetic field passes through the transformer winding. Magnetic flux is the density of magnetic field lines, usually expressed in Weber units. Leakage inductance is the portion of a transformer winding where magnetic flux is not conducted to the next winding. It is caused by air gaps in the middle of the transformer windings, which usually cannot be eliminated.

3. The influence of leakage inductance

Leakage inductance will affect the performance of the transformer, mainly in the following aspects:

1. Leakage inductance Will increase the loss of the transformer. Due to the existence of leakage inductance, the magnetic flux generated in the transformer winding cannot be completely conducted to the next winding, and energy loss will occur during the conduction process.

2. Leakage inductance will reduce the efficiency of the transformer. Since leakage inductance reduces the conduction of magnetic flux, the efficiency of the transformer decreases. This will cause the transformer to generate more heat energy and increase the losses of the transformer.

3. Leakage inductance will affect the electrical performance of the transformer. The electrical properties of the transformer mainly include winding resistance, winding inductance, no-load loss and short-circuit impedance. The presence of leakage inductance will increase resistance, increase inductance, and reduce short-circuit impedance.

4. Leakage inductance calculation method

The calculation of leakage inductance is one of the important aspects of transformer design and manufacturing. Commonly used leakage inductance calculation methods include the following:

1. Theoretical calculation method. This method calculates the leakage inductance based on the circuit construction and winding style of the transformer. The advantage of this method is high accuracy, but the calculation is complex.

2. Experimental measurement method. This method uses measuring transformer short-circuit experimental data to calculate leakage inductance. This method is more effective for small transformers, but it is difficult to measure for large transformers.

3. Numerical simulation method. This method uses finite element analysis software to simulate the transformer and can accurately calculate the leakage inductance. But the calculation is complex and time-consuming.

5. Reasonable range of leakage inductance

Leakage inductance is one of the factors that must be considered in the design and manufacturing of transformers. The reasonable leakage inductance range should be determined based on factors such as the rated power of the transformer, winding materials, and manufacturing processes. Generally speaking, the leakage inductance cannot exceed 10% of the rated capacity of the transformer. If the leakage inductance is too large, it will lead to increased losses, reduced efficiency and reduced electrical performance, and will also pose a threat to the safe operation of the transformer.

6. Summary

Leakage inductance is an unavoidable phenomenon in transformers, which affects the performance and efficiency of transformers. During the design and manufacturing process of the transformer, it is necessary to consider how to reduce the influence of leakage inductance to improve the electrical performance and energy saving effect of the transformer. At the same time, attention must be paid to controlling the leakage inductance range to ensure the safe operation of the transformer.