Common errors and risks in the installation of 10kV SC(B) series dry-type transformers

2025,05,12

In the power system, 10kV SC(B) series dry-type transformers are widely used in industrial, commercial and public facilities due to their high efficiency, environmental protection and maintenance-free advantages. However, irregular operations during the installation process may lead to equipment performance degradation, operating hazards and even safety accidents, affecting power supply reliability.

Today, Jutai will analyze common errors in the installation of 10kV SC(B) series dry-type transformers and deeply interpret the risks of overheating, short circuit, shortened life, etc., to help construction personnel and operation and maintenance teams avoid problems and ensure the safe and stable operation of transformers.

1. Wiring error ‌

Reverse connection of winding or phase error ‌

The reverse connection of the high-voltage or low-voltage winding ends leads to unbalanced three-phase current and local overheating of the winding, which may cause insulation breakdown or burning in severe cases.

When multiple parallel-wound coils are connected in series, the head and tail leads are mixed, resulting in a decrease in the number of coil turns, an increase in the voltage per turn, and accelerated insulation aging.

Improper copper busbar connection ‌

Failure to apply conductive paste or insufficient bolt torque (such as M12 bolts not meeting the 45N·m standard) increases contact resistance, causing overheating or even welding.

2. Installation environment and fixing issues ‌

Insufficient ventilation and moisture-proof measures ‌

Failure to ensure that the humidity of the installation site is ≤85% (at 20°C), or failure to install a dehumidifier in a high-humidity environment (such as a tunnel or offshore platform), resulting in moisture absorption of the epoxy resin layer and reduced insulation performance.

Substandard foundation fixing ‌

The horizontal error of the base is >2mm/m, or no welding/embedded bolts are reinforced, and long-term vibration causes the clamps to loosen and the core to shift, increasing noise and magnetic leakage loss.

Grounding resistance > 4Ω may cause abnormal partial discharge or equipment damage during lightning strike.

3. Incorrect configuration of cooling system ‌

Improper installation of fan ‌

The axial flow fan is not evenly distributed according to the cooling requirements, or the dust on the blades is not cleaned, resulting in reduced forced air cooling efficiency and temperature rise exceeding the 100K threshold.

Temperature control commissioning omissions ‌

Failure to set the over-temperature alarm (130℃) and trip threshold (150℃), or failure to test the automatic start and stop function of the fan, may delay overheating fault handling.

4. Insulation and mechanical damage ‌

Coil surface collision ‌

Failure to use special lifting equipment or manual prying during transportation, resulting in cracking of the epoxy resin casting, partial discharge > 5pC, and shortened service life.

Core lamination process defects ‌

Failure to use the 45° full-bevel joint five-step lamination process, resulting in an increase of more than 10% in no-load loss and noise > 55dB.

5. Omissions in commissioning and acceptance ‌

Key tests were not performed ‌

The insulation resistance of the winding (hot air drying is required when <100MΩ) or the DC resistance (phase-to-phase deviation >2%) was not measured, which may leave hidden defects.

The no-load test was not compared with the factory data (deviation must be ≤±10%), and potential faults of the core or winding were ignored. ‌

Standardized installation should focus on avoiding wiring errors, improper environmental adaptation, heat dissipation failure and mechanical damage, and ensure long-term stable operation of the equipment through strict acceptance tests (such as insulation resistance and temperature control function).

Author:

Mr. jiawenhan

E-mail:

JT13797437282@gmail.com

Phone/WhatsApp:

+86 13797437282