Henan Kaibeite Successfully Exports 8000kVA/33kV On-Load Tap-Changing Power Transformer to Ethiopia
Recently, an 8000kVA three-phase oil-immersed power transformer independently designed and manufactured by Henan Kaibeite Transformer Co., Ltd. passed all factory routine tests. At the customer's request, the transformer was sent to a national accredited third-party laboratory for re-testing of the full set of routine tests. All test items passed, and the transformer has now been shipped to Ethiopia for a local power grid upgrade project.
Fully Customized Design, Leading Technical Parameters
The transformer was designed strictly according to IEC60076 and fully meets the customer's requirements:
| Parameter | Value |
|---|---|
| Rated Power | 8000 kVA |
| HV Voltage | 33 kV |
| LV Voltage | 10 kV |
| Vector Group | Dyn11+d (with balancing winding) |
| Tap Changer | 17-step on-load (OLTC) |
| Cooling | ONAN/ONAF |
| No-load Loss | 6171 W |
| Load Loss | 39724 W |
| Short-circuit Impedance | 7% |
| Total Weight | Approx. 16.6 tons |
Technical Explanation of Dyn11+d and Balancing Winding
Dyn11+d means:
D – HV winding delta connected
y – LV winding star connected with neutral brought out
n – neutral can be directly grounded
11 – phase displacement of 330° (clock notation)
+d – an auxiliary open‑delta winding (balancing winding) is added inside the transformer.
The balancing winding is not used to supply external loads. Its functions include:
Providing a path for zero‑sequence current, improving performance under unbalanced faults
Suppressing third harmonics, improving voltage waveform quality
Acting as a grounding reactor, increasing grounding protection reliability.
The transformer remains a three‑phase transformer; the balancing winding is an auxiliary structure and does not change the main power transmission phase number.
Third-Party Routine Tests – All Passed (Test Report Screenshot Attached)
At the customer's request, the following routine tests were repeated at an independent accredited laboratory (list not exhaustive):
Measurement of winding resistance
Insulation resistance and dielectric dissipation factor
Voltage ratio check and vector group verification at all tap positions
No-load loss and no-load current measurement
Short-circuit impedance and load loss measurement
Separate-source power frequency withstand voltage test
Induced overvoltage withstand test
Pressure seal test for liquid-immersed transformers
All tests passed on the first attempt. The third‑party test report number and key pages are shown in the attached screenshot (see image area).
Rigorous Quality Control Throughout
Every Kaibeite transformer undergoes full IEC routine tests before delivery. For this unit, the customer additionally requested third‑party re‑testing to further confirm product consistency and reliability.
Global Experience You Can Trust
With over 20 years of design and manufacturing experience, we have exported transformers to more than 20 countries and regions, including Ethiopia, Tanzania, Ghana, Philippines, Russia, Bulgaria, Brazil, etc. We offer fully customised solutions up to 35kV / 20000kVA.
Contact Us
Phone / WhatsApp / WeChat: +86 18790806251
Email: info@byttransformers.com
Website: https://www.byttransformers.com
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Kaibeite Industrial Park, No. 121 Xiaozhai Town, Anyang, Henan Province, China
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