I. Introduction
In power transmission and distribution systems, oil-immersed transformers are widely used globally due to their excellent heat dissipation performance, high reliability, and economy. Haiyifeng, a transformer brand specializing in power equipment, adheres strictly to the classic design principles of oil-immersed transformers while incorporating modern production and safety standards to provide efficient and stable solutions for power grids and industrial users.
II. Product Structure and Working Principle
Haiyifeng oil-immersed transformers use mineral oil as the insulation and heat dissipation medium and are either open (with oil conservator) or sealed structures. Their core components include:
Magnetic Core: Constructed from stacked high-permeability silicon steel sheets, providing a low-resistivity magnetic flux path and reducing no-load losses.
Windings: Winded with copper or aluminum wire, with insulating paperboard barriers and partitions used between turns and layers. The insulation thickness increases with voltage levels.
Bushings: Enable connection between the windings and external busbars or cables, ensuring electrical safety.
Oil conservator (oil tank): For open-type transformers, the oil conservator monitors the oil level and provides space for thermal expansion, simplifying operation and maintenance.
Cooling principle: During operation, heat generated by the windings and core is transferred to the mineral oil. As the oil temperature rises, heat is transferred to the transformer's metal casing and heat sinks through natural convection or forced circulation, eventually dissipating into the surrounding air.
III. Safety Design and Engineering Requirements Due to the flammability and fluidity of mineral oil, Haiyifeng fully considers fire safety in the design of transformers and their auxiliary facilities:
A strict minimum clearance must be maintained between the transformer room and building walls and doors.
An oil collection tank or storage pit, firewalls, and other fire-fighting facilities must be installed to prevent the spread of leaked oil.
When the transformer room is located inside a building, the doors must be Class A fire doors.
Compared to dry-type transformers, although the civil engineering and fire protection investment is slightly higher, the product itself has a significant cost advantage and good economic performance throughout its entire life cycle.
IV. Performance Comparison with Dry-Type Transformers
Based on industry-standard technical characteristics, Haiyifeng oil-immersed transformers have the following significant advantages over dry-type transformers:
Comparison Dimensions Haiyifeng Oil-Immersed Transformer Dry-Type Transformer (Reference)
Purchase Cost Approximately 1/2 to 2/3 of dry-type transformers for the same capacity Higher
Heat Dissipation Performance Mineral oil provides uniform heat conduction and good heat dissipation Epoxy resin has poor thermal conductivity
Applicable Voltage No upper limit; suitable for high-voltage transmission and distribution Typically ≤35kV
Temperature Monitoring Oil temperature reflects average temperature with good uniformity Sensor measurement points provide localized temperature
Repairability Windings can be rewound, core can be recycled, and repairable after a fault Overall potting; often the entire unit is scrapped after a fault, and copper/iron recycling is difficult
Application Scope Transmission, distribution, power plants, industrial sites Mainly used for end-point distribution (e.g., buildings, underground)
Note: "Dry-type transformer" in the table above refers to ordinary epoxy resin cast dry-type transformers, not a specific brand.
V. Typical Application Scenarios
Haiyifeng oil-immersed transformers are particularly suitable for the following scenarios:
Substations and transmission lines: For voltage levels of 35kV and above, oil-immersed transformers are the only mature choice.
Industrial parks and mining enterprises: When load fluctuations are large, or the environment is dusty or corrosive, oil-immersed transformers offer excellent sealing and strong resistance.
Outdoor or unattended sites: Oil-immersed transformers have a robust structure and longer maintenance cycles; with oil tanks and level gauges, simple monitoring can be achieved.
VI. Conclusion
Based on classic oil-immersed technology, Haiyifeng transformers provide users with cost-effective, easy-to-maintain, and wide-voltage coverage solutions while ensuring electrical performance and safety compliance. Although oil-immersed transformers require additional investment in fire protection construction, their excellent heat dissipation, maintainability, and significant cost advantages ensure their continued dominance in medium- and high-voltage power systems. In the future, with the promotion of environmentally friendly insulating liquids such as ester oil, Haiyifeng can also upgrade its products towards greater safety and environmental friendliness.
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