100 kVA Copper Oil-Filled Transformer for Industrial Applications

Overview

The 100 kVA copper oil-filled transformer is a fully sealed, oil-immersed distribution unit designed for AC 50 Hz systems with working voltage up to 20 kV. It is built for petroleum, metallurgical, chemical, textile and light industry sites, including environments with high dust loads. Copper windings and a grain-oriented silicon steel core deliver low losses and stable long-term performance.

Core Design

The core is assembled from cold-rolled grain-oriented silicon steel sheets with high permeability. A new core geometry uses full oblique joint stacking, with circular multi-step core columns and equal yoke and limb sections. This construction reduces no-load loss, magnetizing current and noise compared with conventional designs.

Winding Design

Windings are concentric coils with corrugated oil channels for cooling. The high-voltage winding includes a tapping connected to a no-load tap changer mounted on the tank cover, allowing voltage adjustment when the unit is de-energized. Tight tape banding replaces varnish dipping, improving heat transfer and mechanical strength.

Safety and Protection

Transformers from 30 kVA to 2000 kVA are fitted with a pressure relief valve as standard. Gas relays with alarm and tripping contacts can be added to the specification, and larger units accept temperature control devices for automatic monitoring.

Oil Temperature Measurement

A glass thermometer tube base is mounted on the tank top, extending 120 plus/minus 10 mm into the oil. Units from 1000 kVA to 2000 kVA are equipped with an outdoor signal thermometer for remote indication.

Tank and Cooling

The tank uses a corrugated wall with a dust-resistant sprayed paint film. The corrugated panels act as a heat sink and give the tank a breathing function: elastic deformation compensates for oil volume changes with temperature, so no conservator is required and the oil stays sealed from moisture and air.

Applications

Typical installations include industrial workshops, chemical plants, textile mills, mining auxiliary loads and other sites where dust, vibration or space constraints favour a sealed oil-immersed unit over a dry type.

FAQ

Why is the core material called grain-oriented?

The grains of the steel are aligned in the rolling direction so that magnetic flux follows a low-loss path, reducing no-load loss in the transformer.

What does fully sealed mean?

The corrugated tank is welded closed with no air contact, so the oil does not absorb moisture or oxygen, extending oil life and reducing maintenance.

Can the tap changer be operated under load?

No, the standard no-load tap changer must only be operated with the transformer de-energized. Load tap changers are a separate option for voltage regulation duty.

Which oil standards apply?

Mineral insulating oil should meet IEC 60296, with routine testing of dielectric strength and moisture content during maintenance.

Is the 100 kVA rating suitable for continuous industrial load?

Yes, within its design ambient temperature and load profile; for heavily cyclic loads, check the temperature rise limits and consider a larger rating.