Quality & certification
Management systems, test evidence, licences and recognition behind every TBDL transformer. Copies are provided for your project on request.
Management systems
Certified by an accredited certification body (CNAS / IAF). Scope: oil-immersed and dry-type power transformers up to 35 kV, box-type substations, metal-enclosed withdrawable switchgear, low-voltage switchgear and reactive power compensation. First issued March 2019, valid to March 2028.
Type test at the national test centre
- Model
- SZ22-31500/35 kV
- Tested
- January 2026
- Laboratory
- National Quality Inspection and Testing Center for Power Transmission and Distribution Equipment (Shandong), ILAC-MRA
- Result
- Qualified; energy-efficiency Level 1
Includes short-circuit withstand and lightning impulse tests, assessed against GB/T 1094, GB 20052-2024 and IEC 60076-1, -2, -3 and -5. Routine and type test reports for 10 kV dry-type and oil-immersed transformers, 35 kV transformers, box-type substations, switchgear, ring main units and cable branch boxes are also available for the ratings concerned.
Request test reportsLicences and supplier qualification
- Class 2 Power Engineering General Contracting Qualification
- Class 3 Licence for Installing, Repairing and Testing Power Facilities
- State Grid supplier qualification certificate
- Work Safety Licence
- Model registration certificates for the main transformer types
- Daifeng® registered trademark
Government recognition
Also listed in the factory dossier: National Quality Trustworthy Product, AAA credit rating and “contract-honouring and trustworthy enterprise” certificates.
Patents
| Type | Title | Granted |
|---|---|---|
| Invention | Oil-filling device for the production of oil-immersed transformers | November 2023 |
| Invention | Intelligent dry-type transformer and its production process | December 2023 |
| Invention | Simplified mounting structure for transformer current transformers | February 2024 |
| Invention | Transformer condition monitoring and fault early-warning system and method (CN119805075B) | 2025 |
| Utility model | Dry-type transformer with improved heat dissipation | June 2023 |
| Utility model | Frame structure for low-voltage withdrawable switchgear | August 2023 |
| Utility model | Capacitor compensation cabinet with ventilation | September 2023 |
| Utility model | Inspection device for substations | March 2024 |
| Utility model | Integrated stabilising device for oil-immersed transformers | Granted |
| Utility model | Cooling device for oil-immersed transformers | Granted |
How quality is controlled
Incoming materials
Silicon steel, copper, insulation, bushings and tap changers are checked against the purchase specification before use.
Three checks at every process
Each operator, the next process and the inspector check core cutting, winding, insulation, drying, tanking and oil filling.
Routine tests on every unit
Ratio, resistance, losses, impedance, applied and induced voltage tests in the in-house test bay before shipment.
Type and special tests
Type tests at the national test centre for the rating concerned; special tests agreed in the technical specification.
Witnessed release and transport
Buyers may witness the final tests; large units ship with a 3D impact recorder checked on arrival.