Judgment Basis for Level 1 Energy Efficiency of Amorphous Alloy Transformers
With the in-depth advancement of the national "double carbon" strategy, energy-saving and emission-reduction have become core requirements for the upgrading of the power system. As a new type of high-efficiency energy-saving power equipment, amorphous alloy transformers have been widely promoted and applied due to their ultra-low core loss and excellent energy-saving performance. The energy efficiency grade is an important indicator to measure the energy-saving level of transformers, among which Level 1 energy efficiency represents the highest energy-saving standard for transformers, with the lowest energy loss and the best environmental and economic benefits. The judgment of Level 1 energy efficiency of amorphous alloy transformers is not a single indicator evaluation, but a systematic and comprehensive assessment based on national standards, core technical parameters, material performance, and test verification. This article will elaborate in detail on the judgment basis of Level 1 energy efficiency of amorphous alloy transformers, focusing on the core indicators, standard requirements, material guarantees, and test methods, to provide a clear and practical reference for engineering and technical personnel, equipment manufacturers, and relevant inspection departments.
The primary basis for judging the Level 1 energy efficiency of amorphous alloy transformers is compliance with national energy efficiency standards. Since February 1, 2025, all distribution transformers in China have uniformly implemented the new national standard GB 20052-2024 "Energy Efficiency Limit Values and Energy Efficiency Grades for Power Transformers", which has abolished the previous standard GB 24808-2020. This new standard adopts the principle of "classified management and precise energy saving", setting separate energy efficiency limit values for amorphous alloy transformers and silicon steel transformers, which more scientifically reflects the energy-saving characteristics of different material transformers. According to GB 20052-2024, the energy efficiency grades of power transformers are divided into three levels, among which Level 1 is the highest energy efficiency level, with the strictest limit requirements on no-load loss and load loss.
GB 20052-2024 clearly specifies the energy efficiency limit values for amorphous alloy transformers of different capacity levels and voltage grades, which is the core quantitative basis for judging Level 1 energy efficiency. Unlike silicon steel transformers, amorphous alloy transformers have the prominent advantage of ultra-low no-load loss, so the standard sets more stringent no-load loss limits for them, while the load loss limits are basically equivalent to those of high-grade silicon steel transformers. Taking a 2500kVA dry-type amorphous alloy transformer as an example, according to the standard requirements, the no-load loss limit for Level 1 energy efficiency is ≤ 840W, while the no-load loss limit for Level 1 energy efficiency of silicon steel transformers (such as SCB18-2500) of the same capacity is ≤ 2080W, which fully reflects the significant advantage of amorphous alloy materials in reducing no-load loss. For amorphous alloy transformers with rated capacities not listed in the standard tables, the no-load loss and load loss limits for Level 1 energy efficiency shall be determined by linear interpolation to ensure the comprehensiveness and applicability of the standard.
In addition to GB 20052-2024, the judgment of Level 1 energy efficiency of amorphous alloy transformers also needs to comply with relevant supporting standards. For example, oil-immersed amorphous core transformers shall also comply with GB/T 25446 "Oil-immersed Amorphous Alloy Core Power Transformers", and dry-type amorphous core transformers shall comply with GB/T 22072 "Dry-type Amorphous Alloy Core Distribution Transformers". These supporting standards specify the technical parameters, structural requirements, and test methods of amorphous alloy transformers, which provide supplementary basis for the judgment of Level 1 energy efficiency, ensuring that the transformers not only meet the energy loss requirements but also have reliable performance and safe operation.
The second core basis for judging Level 1 energy efficiency is the strict control of core energy efficiency indicators, among which no-load loss and load loss are the two most critical quantitative indicators. The energy loss of amorphous alloy transformers is mainly composed of no-load loss and load loss, and the Level 1 energy efficiency requirement means that both indicators must be strictly controlled within the limit values specified by the standard, and neither can be exceeded.
No-load loss is the core characteristic indicator of amorphous alloy transformers, which is mainly generated by the magnetic hysteresis and eddy current of the core when the transformer is under no-load operation. The ultra-low no-load loss of amorphous alloy transformers is due to the special atomic structure of amorphous alloy materials—amorphous alloy strips are made by rapid solidification technology, with a disordered atomic arrangement, which significantly reduces magnetic hysteresis loss compared with the ordered crystal structure of silicon steel sheets. For Level 1 energy efficiency amorphous alloy transformers, the no-load loss must be controlled to the lowest possible level on the premise of meeting the standard limit. Generally, the no-load loss of Level 1 energy efficiency amorphous alloy transformers is 60% or more lower than that of high-grade silicon steel transformers (such as SCB18), and 30% to 40% lower than that of ordinary silicon steel transformers. For example, the annual no-load power consumption of a 2500kVA Level 1 energy efficiency amorphous alloy transformer (SCBH19-2500) is only 7358kWh, while that of a silicon steel Level 1 energy efficiency transformer (SCB18-2500) of the same capacity is 18221kWh, showing a significant energy-saving effect.
Load loss refers to the energy loss generated by the resistance of the transformer winding when the transformer is under load operation, which is related to the current passing through the winding and the resistance of the winding itself. Although the load loss of amorphous alloy transformers is basically the same as that of high-grade silicon steel transformers, the standard still sets strict limit values for it to ensure the overall energy-saving effect of the transformer. For Level 1 energy efficiency amorphous alloy transformers, the load loss must not exceed the limit value specified by the standard, which requires manufacturers to optimize the winding design, select high-conductivity conductor materials, and reduce the winding resistance to control the load loss within the standard range. For example, the load loss of a 2500kVA Level 1 energy efficiency amorphous alloy transformer is generally controlled between 15400W and 15445W, which is basically equivalent to that of a silicon steel Level 1 energy efficiency transformer of the same capacity.
The third basis for judging Level 1 energy efficiency isthe performance of core materials and structural design. The excellent energy-saving performance of Level 1 energy efficiency amorphous alloy transformers is fundamentally determined by the performance of amorphous alloy materials and the scientificity of structural design. Only when the material performance and structural design meet the corresponding requirements can the transformer achieve the Level 1 energy efficiency standard.
In terms of core materials, Level 1 energy efficiency amorphous alloy transformers must use high-performance iron-based amorphous alloy strips (such as Metglas), with a thickness of only 0.025mm. This ultra-thin strip can significantly reduce eddy current loss, which is one of the key factors for achieving ultra-low no-load loss. The amorphous alloy strips must meet the requirements of relevant standards in terms of magnetic permeability, saturation magnetic induction, and loss characteristics. For example, the magnetic permeability of the amorphous alloy strip should be high enough to reduce the magnetic field strength required for magnetization, thereby reducing magnetic hysteresis loss; the saturation magnetic induction should meet the working requirements of the transformer to ensure the stable operation of the transformer. In addition, the core made of amorphous alloy strips must go through a scientific annealing process to eliminate internal stress, optimize the atomic arrangement, and maximize the soft magnetic properties of the material, which is an important guarantee for achieving ultra-low no-load loss.
In terms of structural design, Level 1 energy efficiency amorphous alloy transformers need to adopt optimized structural designs to reduce energy loss. For the core structure, the amorphous alloy core is usually designed as a closed structure to reduce magnetic leakage loss; the winding structure should be optimized to shorten the winding length, reduce the winding resistance, and thus reduce load loss. In addition, the transformer should be equipped with an efficient heat dissipation system to ensure that the transformer operates at a reasonable temperature. Excessive temperature rise will not only affect the energy efficiency of the transformer but also accelerate the aging of insulation materials and shorten the service life of the transformer. For dry-type amorphous alloy transformers, an efficient air-cooling or water-cooling system should be adopted; for oil-immersed amorphous alloy transformers, an optimized oil circulation system should be designed to improve heat dissipation efficiency.
The fourth basis for judging Level 1 energy efficiency is strict test verification. The energy efficiency grade of amorphous alloy transformers cannot be judged only by design parameters and material performance; it must be verified through strict tests to ensure that the actual energy loss of the transformer meets the Level 1 energy efficiency limit requirements. The test methods and procedures must comply with the requirements of GB 20052-2024 and relevant supporting standards.
The key tests for judging Level 1 energy efficiency include no-load loss test and load loss test. The no-load loss test is carried out under the condition that the primary winding of the transformer is applied with rated voltage and the secondary winding is open-circuited. The test measures the no-load loss of the transformer, which must be less than or equal to the limit value specified by the standard for Level 1 energy efficiency. The load loss test is carried out under the condition that the primary and secondary windings of the transformer are applied with rated current (or the specified load current). The test measures the load loss of the transformer, which must also be within the limit value specified by the standard. During the test, the test environment, test equipment, and test methods must meet the standard requirements to ensure the accuracy and reliability of the test results. For example, the test environment temperature should be controlled within the range specified by the standard, and the test equipment should be calibrated regularly to ensure the accuracy of the measurement data.
In addition to the no-load loss test and load loss test, other relevant tests should also be carried out to verify the comprehensive performance of the transformer, such as temperature rise test, insulation test, and short-circuit withstand test. These tests ensure that the transformer not only meets the Level 1 energy efficiency requirements but also has reliable safety performance and stable operation performance. For example, the temperature rise test verifies whether the temperature rise of the transformer under rated load operation is within the allowable range, which is related to the energy efficiency and service life of the transformer; the insulation test verifies the insulation performance of the transformer, ensuring the safe operation of the transformer.
It should be noted that the judgment of Level 1 energy efficiency of amorphous alloy transformers also needs to consider the type and model of the transformer. According to the classification of amorphous alloy transformers, different models have different energy efficiency performance. For example, among dry-type amorphous alloy transformers, the SCBH19 model is a Level 1 energy efficiency product, while the SCBH17 model is a Level 2 energy efficiency product. Therefore, when judging the Level 1 energy efficiency, it is necessary to combine the model of the transformer to ensure that the model of the transformer meets the Level 1 energy efficiency requirements specified by the standard.
In practical application, the judgment of Level 1 energy efficiency of amorphous alloy transformers needs to integrate the above four aspects of basis: compliance with national energy efficiency standards, strict control of core energy efficiency indicators, qualified material performance and optimized structural design, and passing strict test verification. Only when all these conditions are met can the amorphous alloy transformer be judged as Level 1 energy efficiency. Level 1 energy efficiency amorphous alloy transformers have significant energy-saving advantages, which can effectively reduce the operation cost of the power system and promote the development of energy conservation and emission reduction. For example, a 2500kVA Level 1 energy efficiency amorphous alloy transformer can save nearly 8700 yuan in no-load electricity costs per year compared with a silicon steel Level 1 energy efficiency transformer of the same capacity, and the cumulative energy-saving benefit in 10 years can reach 87000 yuan.
In summary, the judgment of Level 1 energy efficiency of amorphous alloy transformers is a systematic and comprehensive process, with national energy efficiency standards as the core basis, core energy efficiency indicators as the quantitative basis, material performance and structural design as the foundation, and test verification as the guarantee. With the continuous improvement of energy efficiency standards and the continuous progress of amorphous alloy technology, the requirements for Level 1 energy efficiency of amorphous alloy transformers will become more stringent, which will further promote the upgrading of the transformer industry and contribute to the realization of the "double carbon" goal. For equipment manufacturers, they should strictly follow the standard requirements, optimize the design and production process, and improve the energy efficiency level of products; for inspection departments, they should strictly carry out test verification to ensure that the Level 1 energy efficiency products put on the market meet the standard requirements; for users, they should choose Level 1 energy efficiency amorphous alloy transformers according to their actual needs to achieve the dual goals of economic benefit and environmental benefit.
