100kVA Copper Winding Oil Immersed Transformer

Overview of the 100kVA Copper Winding Oil Immersed Transformer

A 100 kVA copper-winding oil-immersed transformer is a three-phase distribution transformer that steps down medium voltage (10 or 11 kV) to 0.4 kV for commercial, agricultural, and light industrial loads. Copper windings provide lower resistance losses and better overload performance than aluminum at the same footprint, which makes this configuration a preferred choice where efficiency and reliability are priorities.

Core and Winding Design

The core is built from high-grade grain-oriented cold-rolled silicon steel with a 45-degree fully inclined joint and step-by-step lamination, which reduces no-load loss and noise. The winding design uses copper conductors with balanced ampere-turns, improving short-circuit strength and thermal performance. Fully sealed vacuum oil injection removes air and moisture from the insulation, strengthening dielectric performance and delaying the aging of the oil and insulating paper.

Technical Parameters

Load loss values are design-dependent and are verified per IEC 60076-1 at the specified reference temperature; the factory datasheet for the selected voltage class provides the exact figure.

Customization Options

The 100 kVA unit can be customized with different voltage levels, load or no-load tap changers, temperature monitoring, oil level monitoring, and pressure relief devices. For harsh environments, an anti-corrosion coating or a stainless-steel enclosure can be specified. These options adapt the transformer to the local grid standard and operating conditions.

Application Scenarios

Typical applications include village and township distribution, small commercial buildings, agricultural processing, small factories, and step-down supply for remote sites. The fully sealed design reduces maintenance and suits locations where regular oil handling is inconvenient.

Operation and Maintenance

Check oil level and color periodically, inspect the silica-gel breather, and keep the tank and bushings clean. Oil quality should be monitored per IEC 60422, with moisture kept below 30 ppm and dissolved gas analysis performed at intervals to detect developing faults.

Frequently Asked Questions

Q: Why choose copper windings instead of aluminum?
Copper has lower resistivity, which reduces load loss and temperature rise for the same rating; it also offers better short-circuit strength and a more compact design, at a higher material cost.

Q: What does fully sealed vacuum oil injection mean?
The oil is filled under vacuum after the tank is evacuated, removing trapped air and moisture from the insulation. The sealed tank then prevents oxygen and humidity from re-entering during service.

Q: Can this transformer operate at 60 Hz?
Yes, the design supports 50/60 Hz operation; loss and temperature-rise values are verified at the specified frequency.

Q: What is the typical service life?
With correct installation and maintenance, a sealed oil-immersed distribution transformer typically operates for 25 to 30 years.

Q: How do I select the vector group?
Yyn0 and Dyn11 are common for distribution. Dyn11 is preferred when harmonic currents and unbalanced loads are present; the choice follows local utility practice.

Q: What loss values should appear on the datasheet for this 100 kVA unit?
For a unit of this design the no-load loss is about 0.34 kW, the no-load current around 1.0% of rated current and the impedance voltage 4%. Load loss is design dependent and is verified per IEC 60076-1 at the reference temperature, so the exact figure comes from the factory datasheet for the selected voltage class.