Factors Affecting Transformer Temperature Rise
The temperature rise of a transformer refers to the increase in its own body temperature due to heat generated during operation.
This parameter is related to the transformer's lifespan: excessive temperature rise leads to performance degradation, accelerates the aging of transformer materials, and reduces the transformer's operational life. Therefore, monitoring the transformer's temperature is crucial to prevent it from exceeding the rated temperature rise, which could cause damage to the transformer equipment.
The factors affecting transformer temperature rise mainly involve two parts: heat generation and heat dissipation. Heat generation is primarily related to the transformer's own loss values; heat dissipation depends on the transformer's cooling method.
First, let's introduce the heat generation in transformers:
Heat generation originates from losses, which include three different types: core hysteresis loss, eddy current loss, and winding (coil) loss. They are defined as:
- Hysteresis Loss: This refers to the energy loss caused by heat release due to the reorientation and internal friction of molecules within the magnetic core material when subjected to an alternating magnetic field, which changes the magnetization orientation.
- Eddy Current Loss: During transformer operation, magnetic flux lines pass through the core, inducing currents in planes perpendicular to these flux lines. Since these currents form closed loops in a swirling pattern, they are called eddy currents. The presence of eddy currents causes the core to heat up, consuming energy; this loss is called eddy current loss.
- Winding Loss: When current flows through the coils, part of the electrical energy is converted into heat loss, which is related to the current and resistance.
Reducing heat generation in transformers mainly involves selecting transformer materials and optimizing the transformer's structural design.
Hysteresis loss is proportional to the area of the hysteresis loop. Soft magnetic materials have narrow hysteresis loops, resulting in relatively lower hysteresis loss. Eddy current loss is related to the core material's permeability, resistivity, thickness, geometry, and the switching power supply frequency. Winding loss can also be optimized by selecting coil materials and cross-sectional area. Furthermore, optimizing the transformer's own design, such as reducing the air gap depth, also helps lower losses.
Transformer cooling methods include natural cooling, forced air (fan) cooling, and insulating oil cooling, among others. Different cooling methods have varying effects, leading to differences in temperature rise. Of course, cooling effectiveness is also related to the transformer's design and constrained by objective environmental factors such as installation conditions and fire safety requirements.
As a transformer manufacturer, we consider the above points during the manufacturing process to achieve standard temperature rise values. Our methods include:
- Using Class H standard enameled wire and new silicon steel sheet materials to reduce the transformer's electrical energy loss.
- Implementing air duct design and varnish impregnation processes to optimize transformer design and improve heat dissipation capability.
- Conducting quality inspections during the manufacturing process to ensure products meet design requirements.
- Providing corresponding passive/active cooling methods tailored to different scenarios and requirements.
Shenzhen Shentebian Electric Equipment Co., Ltd. is a wholly-owned subsidiary of Jishengchang Group. Founded in 2004, the company has its own industrial park and is a technologically advanced, well-established professional transformer manufacturing enterprise. It was one of the earliest companies in Shenzhen to enter the power transformer manufacturing field. STB is the transformer brand under Shenzhen Shentebian Electric Equipment Co., Ltd.
