100KVA 11KV Oil Immersed Transformer

The 100KVA 11KV Oil Immersed Transformer is a medium-voltage distribution transformer designed to step down 11kV primary voltage to low-voltage levels (commonly 400V / 415V / 0.4kV) for industrial, commercial, and utility power distribution systems.

It uses mineral insulating oil as both a cooling and insulating medium, ensuring stable thermal performance and high dielectric strength under continuous load conditions.

Application Case

The 100KVA 11KV Oil Immersed Transformer produced by GUANGBIAN was recently deployed by an African customer to replace a failed transformer that experienced short-circuit damage in a local power distribution system.

In this project, the original transformer used aluminum windings, which were selected for cost-saving reasons. However, due to unstable grid conditions and frequent voltage fluctuations at the user side, the transformer was repeatedly exposed to overload and short-circuit stress, leading to excessive heating and eventual winding failure.

Copper vs Aluminum Windings for 100KVA Transformer

For the 100KVA distribution transformer, GUANGBIAN provides both:

● Copper winding option

● Aluminum winding option

While aluminum windings offer a lower initial cost, their thermal endurance and mechanical strength are relatively lower compared to copper windings.

In unstable power environments - such as:

● Frequent voltage fluctuations

● High inrush current conditions

● Repeated short-circuit events

aluminum windings are more prone to:

● Overheating under overload conditions

● Insulation degradation

● Reduced lifespan in harsh grid applications

Cost vs Reliability Consideration

Although aluminum winding transformers have a lower initial purchase cost, real-world applications show that in unstable grid environments, the total lifecycle cost may increase due to:

● Maintenance requirements

● Unexpected failures

● Replacement costs

Therefore, material selection should be based on actual operating conditions rather than initial price alone, in order to ensure long-term system stability and reduce unplanned downtime.

Technical Document 

Operating Environment

Temperature Conditions:

Long-term Operating Ambient Temperature: -25℃ ~ +45℃.

Maximum Operating Ambient Temperature: Not exceeding +50℃.

Storage and Transportation Temperature:

-40℃ ~ +60℃.

Humidity Conditions:

Relative Humidity: ≤95% at 25℃

Altitude Requirements:

Rated Altitude Adaptation Range: ≤1000 meters

Technical Positioning vs Competitors

Oil-Immersed vs Dry-Type Transformer

Oil-immersed transformers are more suitable for heavy-duty, outdoor, and long-life applications.

Compared with Lower Standards (S9 / S11 / S13 series trend)

● S9: Higher losses, outdated efficiency standard

● S11: Baseline modern efficiency

● S13: Low-loss, high-efficiency design (preferred in export markets)

A 100KVA transformer designed with S13 core technology can reduce no-load losses by 15–30% compared to S11, improving ROI over long-term operation.

Market-Level Competitor Positioning

Compared with generic manufacturers:

● Better loss control (no-load + load loss optimization)

● Stronger short-circuit withstand capability

● Improved sealing technology (oil leakage prevention)

● Better compliance documentation for export markets

Our Factory

Sheet metal workshop

Foil winding workshop

Winding workshop

Winding oven workshop

Transformer assembly workshop

Transformer commissioning workshop

FAQ

Q1: What is the lifespan of a 100KVA oil immersed transformer?

Typically 20–30 years, depending on load conditions, maintenance, and installation environment.

Q2: Can it be used outdoors?

Yes. Oil-immersed transformers are specifically designed for outdoor substations and harsh environments.

Q3: What maintenance is required?

● Regular oil level inspection

● Periodic oil dielectric testing

● Bushing and connection tightening

● Temperature monitoring

Maintenance intervals are usually longer than dry-type transformers.

Q4: What is the difference between 11KV and 10KV transformers?

11KV is a higher system voltage level, commonly used in international distribution networks. Performance principles remain similar, but insulation requirements are stricter.

Q5: Is it suitable for renewable energy projects?

Yes. It is widely used in solar and wind step-down distribution systems due to its stability and overload tolerance.