How to Efficiently Reduce Losses in Transformers?

Transformers are an important component of the power grid. They are also the foundation for ensuring a safe power supply. Reducing losses in transformers are an important issue for achieving energy conservation and ensuring the economic operation of the power system.

Therefore, it is necessary to take efficient measures to reduce losses in transformers. The following is a brief analysis of the specific ways to reduce transformer losses from aspects such as the causes of transformer losses and measures to reduce them, for your reference.

What is Copper Loss in Transformer?

Transformer losses mainly consist of copper loss and iron loss.

Copper loss refers to the power dissipation due to the resistance of the transformer when primary and secondary currents flow through the windings. Since transformer windings are typically made of copper wire, so this type of loss is called copper loss. Also known as I²R loss (means current square × resistance). It is a load loss that is proportional to the square of the load current.

During transformer winding, large amounts of copper wire are required, and these wires inherently possess electrical resistance. When the transformer operates at rated load, this resistance causes some power to be consumed and converted into heat as current flows through the windings—this portion of the loss is known as copper loss.

What is Iron Loss in Transformer?

Iron loss refers to the energy consumption of the core in the magnetic circuit of a transformer under rated voltage (secondary open circuit). It is also known as iron consumption and no-load loss.

The iron loss amount is related to the primary voltage of the transformer. It has nothing to do with the secondary side of the transformer. As long as the primary voltage is applied, the value of iron loss remains basically unchanged.

Iron loss is specifically divided into eddy current loss, hysteresis loss, additional iron loss and other parts. Among them, eddy current loss and hysteresis loss are related to the core material of the transformer itself.

In conclusion, copper loss and iron loss are the main reasons for the temperature rise during the operation of transformers.

Among them, iron loss is a fixed loss. As long as there is voltage in the transformer once, iron loss will definitely occur. As long as the primary voltage in the line remains unchanged, the iron loss will not change.

Copper loss is a variable loss that is related to the size of the load and varies with changes in load current and temperature.

When a transformer is in operation, the input power is always greater than the output power due to power losses, including copper losses and core (iron) losses. When the copper loss is equal to the iron loss, the transformer’s loss rate is the lowest.

How to Reduce Losses in Transformers?

The loss of a transformer mainly depends on its design and manufacture. When designing and manufacturing transformers, effective measures can be taken to reduce the loss.

How to Reduce Copper Loss in Transformer?

1. Adopt new materials such as oxygen-free copper.

Oxygen-free copper material is low in loss and resistance, with a relatively low cost. It has strong corrosion resistance and easy to obtain. Its processing technology is also simple. Through the processing of the upward pull method, it features lower resistivity, smaller volume, and good energy-saving effect. It can effectively reduce the internal resistance of the winding of distribution transformers, enhance the short-circuit resistance of transformers, and achieve the purpose of energy conservation and consumption reduction. Comprehensively enhance the economic efficiency of distribution transformers.

2. Adopt internal protection measures such as internal shielding windings to effectively reduce the volume of the transformer and lower its energy consumption.

3. Determine the insulation structure of the transformer based on scientific theoretical calculations. By adopting advanced new processes, appropriately reduce the structural dimensions of the main insulation and longitudinal insulation. Decrease the diameter of the copper wire, and change the working parameters of the circuit to effectively reduce the AC resistance of the windings.

4. By adjusting the ampere-turn balance, limiting the thickness of the flat wire, installing magnetic shielding on the upper and lower parts of the winding, installing electrical shielding on the tank wall, and scientifically selecting the commutation method of the parallel conductors – all these actions can effectively minimize the additional losses caused by leakage flux.

How to Reduce Hysteresis Loss/Iron Loss in Transformer?

① Use high-quality core materials with high magnetic permeability, such as high-silicon steel sheets and amorphous alloy sheets. These materials can reduce hysteresis and the total amount of the core. Moreover, processing methods like step stacking, plasma treatment, laser irradiation, and mechanical indentation can also be adopted to further reduce losses.

② Optimize the assembly process of the core to reduce the process loss coefficient of the core. When assembling the core of a transformer, use wound cores or three-dimensional cores. Wound cores are continuously wound according to the orientation of silicon steel sheets. Compared with the traditional laminated core, wound cores have no four sharp corners.

After being fully and continuously wound through the annealing process, additional losses can be effectively reduced. The three-dimensional core, due to its yoke iron being in a three-dimensional triangular shape, has a yoke iron mass that is 25% lighter than that of a flat coiled core. It can be seen from this that, compared with the traditional laminated core, the use of wound cores and three-dimensional cores in transformers is more energy-efficient.

③ Take other methods, such as reducing the size of the core window to lower the core weight, designing a non-resonant core to reduce noise and save energy, and improving the core structure to reduce the core lap width and lower the loss. All these measures can effectively reduce core loss.

How to Reduce Stray Losses in Transformer?

① Regarding the loss of structural components such as core clamps, use low-magnetic or non-magnetic materials to reduce the stray loss of the internal structure.

② For parallel conductors such as leads and bushings with large currents, use copper plates for shielding or non-magnetic materials to reduce the stray loss of the bushing seat.

• Copper plate shielding can generate current on the surface of the shielding body to prevent magnetic flux from entering, thereby reducing the loss of metal structural components.
• Non-magnetic materials can attract leakage magnetic flux through the transformer core, keeping it at a distance from solid metal components.

③ The fuel tank can adopt new types of coolers, energy-saving fans, corrugated fuel tanks and other economical and energy-saving cooling methods to effectively reduce stray losses. For instance, adopt high-efficiency and low-noise reinforced plastic fans, variable frequency and pressure-regulating coolers, etc..