| Main Product Types | Cast-resin dry-type transformers, vacuum-pressure-impregnated transformers, and air-insulated transformers | Cast-resin designs are widely used where fire safety, low maintenance, and indoor installation are important. |
| Common Capacity Range | Approximately 50 kVA to 2,500 kVA for common distribution applications; larger project units can reach several MVA | The required rating depends on connected load, demand factor, starting current, redundancy, and future expansion. |
| Primary Voltage | Typical medium-voltage primary ratings include 6 kV, 10 kV, and 35 kV; other ratings are available for specific systems | The primary voltage must match the utility or industrial distribution network and the required insulation level. |
| Secondary Voltage | Common low-voltage outputs include 400 V, 415 V, and 480 V, depending on the destination power system | Secondary voltage, frequency, phase configuration, and neutral arrangement should be confirmed before production. |
| Cooling Method | AN (air natural) and AF (air forced) cooling | AN cooling is suitable for standard loading; AF cooling can increase available capacity when thermal conditions and noise limits permit. |
| Insulation and Temperature Class | Class F and Class H insulation systems are commonly used; actual temperature rise is specified by the design and applicable standard | Higher thermal-class materials can improve thermal endurance, but system design, ventilation, and loading remain critical. |
| Enclosure Protection | Common enclosure levels include IP00, IP20, IP23, and IP31 | The enclosure should be selected according to indoor or outdoor installation, dust, moisture, access control, and cooling requirements. |
| Applicable Standards | IEC 60076-11 for dry-type power transformers; IEC 60076-1 for general transformer requirements; GB/T 10228 and GB 20052 for applicable Chinese requirements | A qualified supplier should identify the exact edition, test requirements, efficiency class, and destination-market compliance route. |
| Routine Factory Tests | Winding resistance, voltage ratio, phase displacement, no-load loss, load loss, impedance voltage, dielectric tests, and partial-discharge testing where specified | Factory test reports provide evidence that the completed unit meets the approved technical specification. |
| Frequency | 50 Hz is common in China; 60 Hz designs are produced for compatible export and industrial systems | Frequency affects losses, impedance, thermal performance, and compatibility with the connected network. |
| Tap Configuration | Off-circuit tap links are commonly provided, often within a small percentage range around the rated primary voltage | Tap settings should reflect actual utility voltage and must only be changed when the transformer is de-energized. |
| Typical Applications | Commercial buildings, data centers, hospitals, factories, rail systems, renewable-energy facilities, and urban substations | Dry-type equipment is preferred in many indoor and fire-sensitive environments because it does not use liquid insulation oil. |
| Environmental Design Conditions | Standard designs are generally based on specified ambient temperature, altitude, humidity, ventilation, and installation conditions | High altitude, corrosive atmospheres, high humidity, dust, and restricted ventilation may require derating or special construction. |
| Key Purchasing Criteria | Rated power, voltage ratio, insulation level, losses, impedance, noise, enclosure, cooling, dimensions, protection, and certification | A complete technical schedule is more reliable than comparing suppliers by price or rated capacity alone. |
| Supplier Evaluation Focus | Design capability, production traceability, coil and core quality, testing facilities, documentation, after-sales service, and export experience | Manufacturing capability should be verified through drawings, type-test evidence where required, routine test records, inspection plans, and warranty terms. |