Amorphous Alloy Core Oil-immersed Transformer

Overview of Amorphous Alloy Transformers

An amorphous alloy transformer is an energy-efficient oil-immersed or dry-type distribution transformer whose core utilizes amorphous alloy ribbon instead of traditional silicon steel sheets. Amorphous alloy is composed of fundamental elements such as iron, nickel, cobalt, boron, and carbon. Its atoms exhibit a disordered amorphous structure, forming an isotropic soft magnetic material characterized by low magnetization power, high permeability, low coercivity, and structural defects free of obstacles to domain wall motion. The amorphous alloy has an extremely thin thickness of only 0.027 mm, resulting in a correspondingly smaller stacking factor of 0.75 to 0.8, and a very high electrical resistivity (1.3~1.5μΩ.m), which is 3 to 6 times that of silicon steel sheets. Consequently, the hysteresis loss during the magnetization process is extremely low, and the no-load loss is far lower than that of traditional silicon steel transformers.

   Regular Alloy(Crystalline Structure)           Amorphous Alloy(Non Crystalline Structure)                              Amorphous alloy transformer core

Core Structure & Components

• Windings: Largely identical to those of conventional transformers.

• Iron Core (The Key Distinction): Constructed by winding ultra-thin amorphous alloy ribbons, typically featuring a four-frame, five-limb structure. The core is formed directly through winding without stamping or shearing.

• Auxiliaries: Equipped with standard transformer tanks, cooling systems, and protection components, categorized into oil-immersed and dry-type designs.

Working Principle

Amorphous alloy transformers operate on the principle of electromagnetic induction for voltage transformation:

• No-Load Performance: Because amorphous alloy atoms possess a disordered, non-crystalline structure resulting in high magnetic permeability and low coercivity, magnetic hysteresis loss is extremely low during magnetization. Consequently, no-load losses are significantly lower than those of silicon steel transformers (reduced by 60% to 80%).

• Load Performance: The windings handle load power transmission, rendering load losses comparable to those of conventional transformers.

Typical Applications

Amorphous alloy transformers are primarily deployed in scenarios characterized by fluctuating loads and prolonged light-load conditions, including:

• Distribution networks/Residential communities/Commercial buildings/Industrial parks/Municipal infrastructure /Regions prioritizing loss reduction, energy conservation, and carbon emission reduction.

Advantages & Disadvantages

Advantages

1. Massive No-Load Loss Reduction: No-load losses drop by 60% to 80% compared to standard silicon steel transformers, delivering exceptional energy-saving performance under light-load operating conditions.

2. Low Exciting Current: Exhibits a smaller no-load (exciting) current.

3. Reduced Acoustic Noise: Operates with slightly lower noise levels, yielding prominent energy-saving and emission-reduction benefits.

Disadvantages

1. Mechanical Fragility: Amorphous alloy material is mechanically brittle and highly sensitive to mechanical shock and vibration, imposing stringent requirements on transportation and installation.

2. Complex Manufacturing: The core-winding process is intricate, resulting in higher initial capital costs.

3. Limited Over-Excitation Capability: Demonstrates poorer performance under over-excitation conditions.

4. Bulkier Core: The physical volume of the core tends to be larger.

5. No Load-Loss Advantage: Offers no distinct advantage in load losses, meaning energy-saving economic returns are less pronounced under heavy-load conditions.

Main Product Performance Parameters of YTAA15 Amorphous Alloy Transformers

10 FAQs regarding amorphous alloy transformers:

1. What are the specific advantages of amorphous alloy transformers in terms of no-load losses compared to traditional silicon steel sheet transformers?

• Answer: The atomic structure of amorphous alloy material is arranged irregularly, requiring minimal energy for magnetization and demagnetization; therefore, its coercive force is much lower than that of traditional grain-oriented silicon steel sheets. In actual operation, the no-load loss (core loss) of an amorphous alloy transformer is typically 60% to 70% lower than that of a standard silicon steel transformer of the same capacity, making it especially suitable for distribution scenarios with long-term no-load or light-load operation (such as rural power grids, underground substations, and intermittent-load factories).

2. Does the performance of the amorphous alloy core degrade under high-temperature or overload operating environments?

• Answer: Amorphous alloy materials are relatively sensitive to mechanical stress and temperature changes. When the operating temperature exceeds its Curie point (approximately 400°C, which is far higher than normal operating temperatures) or when it is subjected to severe overloads for a long period, internal stresses may change, causing core losses to increase to a certain extent. Therefore, during design and selection, temperature rise margins must be strictly controlled (typically using Class A or Class H insulation systems combined with forced air cooling), avoiding long-term operation beyond nameplate capacity.

3. What are the special requirements for amorphous alloy transformers regarding their ability to withstand short-circuit impacts?

• Answer: Because amorphous alloy ribbons (only about 0.03mm thick) are hard and brittle, traditional silicon steel stacking processes cannot be used during manufacturing; instead, wound core structures are mostly adopted. When subjected to external short-circuit impacts, the massive electrodynamic forces place higher demands on the mechanical fixing structures of the core and windings. High-quality products must utilize high-strength clamping components, epoxy resin binding, or special anti-sudden-short-circuit structural designs to prevent core displacement or localized stress concentration that could worsen no-load losses.

4. Why does the noise performance of amorphous alloy transformers differ from that of ordinary silicon steel transformers?

• Answer: Amorphous alloy materials have a larger magnetostriction coefficient (about 1.5 to 2 times that of conventional silicon steel sheets), which means they are more prone to physical vibration under alternating magnetic fields, resulting in relatively higher inherent electromagnetic noise. In practical applications (especially in noise-sensitive residential or commercial areas), manufacturers typically employ special vibration-damping pads, multi-point flexible core connections, high-quality protective enclosures, or reduced core operating magnetic flux densities to lower noise levels.

5. How should one choose between amorphous alloy dry-type transformers and oil-immersed transformers for specific application scenarios?

• Answer:

• Oil-immersed amorphous alloy transformers: Mostly used for outdoor pole-mounted transformers, small outdoor substations, and industrial enterprise step-down stations. They offer high heat dissipation efficiency and a short initial investment payback period, but face restrictions in locations with strict fire and explosion prevention requirements.

• Dry-type amorphous alloy transformers: Mostly used in high-rise buildings, commercial complexes, basements, and indoor substations. Although they have higher requirements for moisture resistance and heat dissipation, they eliminate oil leakage risks and still deliver excellent no-load energy-saving benefits.

6. How do amorphous alloy transformers perform in industrial loads with high harmonic content (such as frequency converters and rectifying equipment)?

• Answer: Currents containing a large amount of high-order harmonics cause additional stray losses in transformer windings and lead to localized core overheating. Because amorphous alloy ribbons are extremely thin, eddy current losses generated by high-frequency magnetic fields are relatively small, but total harmonic distortion (THD) caused by harmonics can still drive up overall temperature rise. At industrial sites with severe harmonics, derating must be applied during selection, or manufacturers must be required to configure anti-harmonic designs meeting specific K-factor requirements.

7. How is the Return on Investment (ROI) of an amorphous alloy transformer typically calculated compared to traditional transformers?

• Answer: Although the initial purchase cost of an amorphous alloy transformer is typically 15% to 30% higher than that of an ordinary silicon steel transformer, its extremely low no-load losses mean that 24-hour continuous operation saves a significant amount of electricity. In industrial settings with higher electricity prices or lower transformer load rates (such as 30% to 50%), the initial premium cost can typically be fully recovered through electricity bill savings within 3 to 5 years, with all subsequent savings turning into pure profit.

8. What special anti-vibration and anti-deformation specifications apply during the transportation and lifting of amorphous alloy transformers?

• Answer: Due to the lack of mechanical support from rigid stacked silicon steel, amorphous alloy cores have relatively fragile overall mechanical rigidity. During long-distance logistics transportation and on-site lifting, acceleration impacts must be strictly limited to prevent relative displacement inside the core or the generation of additional mechanical stress. Products shipped from the factory are typically equipped with three-dimensional impact recorders, and lifting must strictly follow designated load-bearing points for vertical hoisting, strictly prohibiting the application of external forces directly through the core or low-voltage leads.

9. What impacts do climatic environments (such as high humidity, coastal salt spray, and sandstorms) have on the outdoor application of amorphous alloy transformers?

• Answer: Amorphous alloy ribbons themselves undergo surface insulation coating treatments; however, in high-humidity, salt-spray, or acid-rain environments, if the transformer enclosure protection rating (IP code) is insufficient, moisture ingress into the core gaps can cause localized corrosion, subsequently leading to degraded insulation or abnormal increases in core loss. Therefore, amorphous alloy transformers used in harsh environments must adopt high-standard anti-corrosion coating processes (such as C4/C5 corrosion protection classes) or fully sealed gas/oil tank structures.

10. What is the dismantling and recycling process for an amorphous alloy transformer after it reaches the end of its service life?

• Answer: Amorphous alloy materials are primarily composed of elements such as iron, nickel, cobalt, boron, and silicon. At the transformer decommissioning and recycling stage, the core cannot be simply melted and restamped like silicon steel sheets; instead, high-temperature remelting or downgrade recycling can be achieved through specific metallurgical furnace temperature-control technologies. Standard manufacturers and recycling enterprises typically employ whole-process thermal treatment separation methods to strip insulating resins/oil contamination from the metal matrix, achieving high-efficiency resource recovery of the core alloy.

Quality Assurance & Core Process：

1. Amorphous Alloy Ribbon

We adopt high‑quality amorphous alloy ribbon as transformer core material, featuring ultra‑low core loss performance far superior to conventional grain‑oriented silicon steel. The nominal thickness of amorphous ribbon is only 0.025 mm. The closed wound core is produced by specialized slitting and winding equipment to minimize mechanical stress on the amorphous material. The core is assembled with optimized clamping force to avoid brittle fracture of amorphous strips. This design delivers outstanding no‑load loss reduction, excellent energy‑saving performance and stable magnetic properties under operating conditions.

2. High-Conductivity Winding Conductors & Core-Coil Assembly

High-conductivity electrolytic copper or aluminum conductors are selected based on transformer capacity, voltage class, and loss requirements. Incoming materials undergo stringent quality inspections for dimensions, electrical resistance, surface quality, and traceability. During the winding process, conductor tension, winding height, layer insulation, and conductor positioning are precisely controlled to ensure resistance consistency and mechanical stability, thereby minimizing load losses and temperature rise during operation.

During core-coil active part assembly, coil height, axial clamping force, radial support, and spacer block positioning are precisely controlled. Proper mechanical clamping prevents coil displacement during transport, normal operation, and short-circuit conditions. Meanwhile, clamping forces are strictly regulated to avoid excessive stress on conductors and insulation materials. Our mechanical design accounts for both radial and axial electromagnetic forces, safeguarding short-circuit withstand capability and long-term dimensional stability.

3. Advanced Insulation System (Oil-Immersed & Dry-Type)

For oil-immersed transformers, we utilize high-grade insulation materials, including Kraft paper, thermally upgraded paper, pressboard, and transformer-grade laminated board. For dry-type transformers, we employ DMD, NMN, Nomex, fiberglass, and epoxy resin systems. Insulation thickness, overlap width, oil duct dimensions, electrical clearances, and mechanical positioning are strictly regulated. All insulation materials are stored under climate-controlled conditions to minimize moisture absorption and contamination, ensuring stable dielectric strength and long-term insulation reliability.

4. Controlled Vacuum Drying

We apply a controlled drying curve regulated by temperature, vacuum level, and duration parameters, rather than relying on fixed cycle times. The process comprises controlled pre-heating, evacuation, primary drying, and final soak phases, with continuous temperature and vacuum monitoring and logging. End-point determination is based on validated process criteria and moisture limits. This process minimizes residual moisture in cellulose insulation, maximizing dielectric strength, retarding insulation aging, and extending overall service life.

5. Vacuum Epoxy Resin Casting

For cast-resin dry-type transformers, we utilize controlled vacuum casting technology. Resin-to-hardener ratio, material temperature, vacuum level, mixing time, pouring conditions, and curing temperatures are strictly regulated. Vacuum degassing minimizes micro-voids prior to pouring, while controlled curing ensures stable mechanical and thermal properties. Finished coils undergo thorough visual and electrical inspections, including routine partial discharge (PD) testing. This process eliminates internal voids, ensuring reliable insulation performance throughout the transformer's service life.

6. Clean Assembly & Torque Control

Final assembly takes place in a controlled environment to minimize contamination from dust, metallic particles, and foreign objects. Critical components are inspected for cleanliness, dimensional accuracy, and insulation condition. Electrical clearances, lead routing, grounding connections, and mechanical supports are rigorously controlled throughout assembly. Critical bolted joints are tightened to specified torque values using calibrated equipment and fully logged. Prior to sealing the tank or enclosure, a thorough internal inspection ensures no tools, loose parts, or foreign material remain.

7. 100% Factory Routine Testing

Every transformer undergoes 100% routine testing prior to dispatch, complying with applicable IEC standards, approved technical specifications, and customer requirements. Standard test routines include winding DC resistance, voltage ratio, vector group verification, no-load loss and current, load loss and short-circuit impedance, applied voltage withstand, and induced overvoltage withstand tests. Special tests—such as partial discharge (PD), dissipation factor (tan δ), or sweep frequency response analysis (SFRA)—are conducted upon request. Each unit is assigned a unique serial number linked to its material records, manufacturing data, and final test reports, ensuring end-to-end traceability.

Youth Transformer Co.,Ltd.