4MVA 11kV to 415V Oil-Filled Transformer | Technical Specifications and Best Price

In large-scale power distribution scenarios such as heavy industry, commercial complexes, infrastructure projects, and power plants, the 4MVA 11kV to 415V oil-filled transformer plays a crucial role in ensuring stable and efficient power supply. Engineers and procurement managers often face the challenge of balancing technical reliability with procurement cost. Selecting the right configuration can significantly reduce lifecycle expenses while improving system performance. This article provides detailed technical specifications, structural advantages, and pricing insights to help buyers obtain the most cost-effective solution.

4MVA 11kV/0.415kV Oil-Filled Transformer Technical Specifications

Rated Capacity and Voltage Combination

Rated Capacity: 4000 kVA (4MVA)

High Voltage Side: 11 kV ±2x2.5% with off-load tap changer or on-load tap changer

Low Voltage Side: 0.415 kV (415V)

Connection Group: Dyn11, commonly used in distribution systems for suppressing third harmonics and improving voltage stability.

Frequency and Number of Phases

Number of Phases: Three-phase

Rated Frequency: 50Hz or 60Hz depending on local grid standards.

Impedance Voltage

Short-circuit impedance typically ranges from 6% to 8%. For 4MVA large-capacity transformers, selecting 6.0% to 7.5% impedance effectively limits short-circuit current while maintaining reasonable voltage regulation.

Cooling Method

ONAN (Oil Natural Air Natural) cooling is suitable for continuous rated load operation and requires minimal maintenance. ONAF (Oil Natural Air Forced) cooling adds external fans and can increase output capacity by approximately 30% to 40%, making it ideal for short-term overload conditions.

Insulation Level and Loss Standards

Insulation Class: Class A or Class B

No-load loss designed according to IEC 60076 or GB 20052 energy efficiency standards.

Load loss measured at a reference temperature of 75°C to ensure accuracy under operating conditions.

Protection Rating and Accessories

Protection class can be configured as IP20 for indoor installation or IP23 for outdoor environments. Standard accessories include oil level gauge, Buchholz relay, pressure relief valve, temperature indicator, and tap changer.

4MVA 11kV/0.415kV Transformer Structure and Material Advantages

High-Efficiency Core Design

The transformer core uses high-permeability cold-rolled grain-oriented silicon steel sheets. This design significantly reduces no-load loss and improves overall efficiency, making it suitable for long-term continuous operation.

High-Quality Winding Materials

Copper windings are typically adopted for 4MVA transformers. Copper conductors offer lower resistance, better thermal performance, and stronger short-circuit withstand capability compared to aluminum alternatives.

Reliable Insulation System

High-quality mineral insulating oil combined with premium insulation paper and pressboard materials ensures strong dielectric performance and long service life.

Optimized Cooling Structure

Corrugated tank design or radiator cooling fins enhance heat dissipation efficiency, reduce hotspot temperature, and extend equipment lifespan.

4MVA Oil-Filled Transformer Price Analysis

Market Reference Price

China Ex-Factory Price: approximately USD 18,000 to USD 35,000

Export FOB Price: approximately USD 22,000 to USD 45,000

Actual prices vary depending on copper cost, efficiency level, cooling configuration, certifications, and brand positioning.

Key Factors Affecting Price

Raw material cost fluctuations, especially copper and silicon steel.

Energy efficiency level and low-loss design requirements.

Cooling method such as ONAN or ONAF.

Manufacturing process and brand reputation.

Additional accessories including temperature control systems and explosion-proof devices.

How to Obtain the Best Price for a 4MVA Oil-Filled Transformer

Consider Raw Material Cost Timing

Copper and silicon steel account for a large portion of transformer cost. Buyers can negotiate a price lock period with suppliers to avoid market fluctuations. End-of-quarter purchasing often provides better discounts.

Select Appropriate Energy Efficiency Level

High-efficiency transformers may cost 15% to 20% more initially, but they significantly reduce operating losses. For continuously loaded 4MVA transformers, the energy savings can offset the additional cost within a short period.

Choose Standard Configurations

Non-standard customization increases production time and cost. Selecting standard manufacturer designs can reduce price by approximately 10% to 15% and shorten delivery time.

Work Directly with Manufacturers

Purchasing directly from transformer manufacturers eliminates intermediary costs. Comparing quotations from multiple production regions such as China, India, and Turkey can reveal substantial savings.

Bulk Procurement Strategy

If multiple transformers are required for a project, consolidated procurement can achieve volume discounts and reduce logistics costs.

The 4MVA 11kV to 415V oil-filled transformer is essential equipment for medium and large-scale power distribution systems. When selecting a transformer, buyers should evaluate not only price but also efficiency, reliability, material quality, and manufacturer service capability. A properly configured transformer ensures stable operation, lower energy loss, and long-term economic benefits.

Contact us today to receive a competitive quotation and technical support for your project.