Product Overview
The 11kv Dry Type Transformer is an industrial-grade unit engineered for high-reliability power distribution. Featuring a step-lap CRGO core and vacuum-cast epoxy copper foil windings, this cast resin design provides enhanced short-circuit strength, low noise, and digital thermal monitoring compatibility.
Application & Selection Guide
1. What is an 11kV Dry-Type Transformer?
An 11kV dry-type transformer is a solid-insulation, oil-free power transformer designed with a primary voltage rating of 11,000 volts (11 kV). It uses high-temperature vacuum-cast epoxy resin to encapsulate its copper or aluminum windings, providing a robust, maintenance-friendly, and fire-safe solution for stepping down medium-voltage (11 kV) grid power to standard low-voltage levels (e.g., 400V) for end-use distribution.
Key features include:
Primary Voltage : 11,000V, common in many global 50Hz distribution systems.
Solid Insulation : Epoxy resin provides excellent dielectric strength and mechanical protection.
Dry-Type Design : No flammable oil, enabling safe indoor installation without the need for oil-containment pits.
Self-Extinguishing : The resin material is fire-retardant and self-extinguishing, minimizing fire hazards.
2. What Applications Does an 11kV Dry-Type Transformer Suit?
This transformer is specifically tailored for medium-voltage distribution networks that operate at an 11 kV primary voltage. It is the ideal power solution for:
Industrial Factories ：Automotive plants, heavy engineering workshops, textile mills, food and beverage production lines, and pharmaceutical facilities that have medium-to-large power demands (e.g., with a 400 kVA unit, supporting ~320-400 kW of load) and require a safe, reliable, and low-maintenance power source indoors.
Indoor Substations ：Serves as the main step-down transformer in utility-owned or facility-owned indoor substations, particularly where 11 kV is the standard distribution voltage. It converts high primary voltage to safe low voltage (e.g., 400V) for distribution within a building, campus, or industrial park.
Commercial & Public Infrastructure ：Large shopping centers, hospitals, airport terminals, data centers, and high-rise office towers that have dedicated indoor electrical rooms and require high fire-safety standards, quiet operation, and reliable power for critical systems.
3. What Are the Differences Between 11 kV and 10 kV Transformers?
The primary difference lies in their rated primary voltage, which dictates the grid system they can connect to. Choosing the wrong voltage will result in improper voltage regulation and equipment malfunction. Here is a simplified comparison:
| Comparison Aspect | 11 kV Transformer | 10 kV Transformer |
|---|---|---|
| Primary Voltage | Rated for 11,000V power input. | Rated for 10,000V power input. |
| Typical Grid Standards | Commonly used in UK, European, South African, Australian, and many Asian 50Hz distribution networks. | Widely used in Chinese, Vietnamese, and some other Asian 50Hz distribution networks. |
| Tap Changer Adjustment | Both usually feature no-load tap changers (NLTC) with a ±2x2.5% range on the primary side to compensate for grid voltage variations. | |
| Application Note | Must be used strictly in 11 kV systems. Connecting an 11kV transformer to a 10kV grid will result in a lower-than-rated secondary output voltage. | Must be used strictly in 10 kV systems. Connecting a 10kV transformer to an 11kV grid may cause over-excitation and overheating. |
Simple Rule ：Always match the transformer's primary voltage to your utility's supply voltage. Always confirm your local grid standard before ordering.
4. Indoor Installation and Maintenance
Indoor Installation ：Installing this dry-type transformer indoors offers significant advantages and requires specific considerations:
Environment ：Install in a well-ventilated, clean, and dry room (IP20/IP23 enclosure recommended). Ambient temperature should not exceed 40°C; altitude should be below 1000m for standard rating (derating may apply for higher altitudes).
Foundation & Spacing ：Provide a level, vibration-damping foundation (e.g., concrete base with spring isolators). Maintain adequate clearance from walls and other equipment for cooling airflow and maintenance access (refer to drawings).
Cable Connections ：Ensure all high and low-voltage cable connections are secure and correctly phased. Use appropriate cable lugs and torque tools as specified.
Grounding：Properly ground the transformer tank and core according to local electrical codes to ensure safety.
Maintenance ：
The "maintenance-free" nature of dry-type transformers simplifies upkeep, but regular checks ensure long-term reliability:
Regular Visual Inspection ：Periodically (e.g., every 6-12 months) inspect for dust accumulation (clean with dry compressed air or vacuum), signs of overheating (discoloration of varnish/resin), or any physical damage to the enclosure and connections.
Thermal Monitoring ：Continuously monitor winding temperature via the digital display or remote system. Log temperatures to identify unusual trends.
Fan System Check ：If equipped with forced air cooling (ANAF), verify fans operate smoothly, are free of debris, and activate/deactivate at the correct temperatures as per controller settings.
Periodic Electrical Testing ：While routine oil testing is unnecessary, it is recommended to perform annual insulation resistance (IR) tests and periodic partial discharge (PD) measurements (e.g., every 3-5 years) to track insulation health.
Scope of Supply
Product: 11KV dry type transformer
Number of phases: Three-phase
Rated power: 50KVA - 3150KVA dry type transformer
Primary voltage: 11,000V
Secondary voltage: 400V
Frequency: 50Hz
Vector Group: Dyn11
Customizable production: Available
Technical Specifications
|
Model |
SCB-400kVA-11/0.4 |
|
Type |
Dry type Transformer |
|
Standard |
IEC60076 |
|
Rated Power |
400kVA |
|
Frequency |
50HZ |
|
Phase |
Three |
|
Cooling Type |
ANAF |
|
Primary Voltage |
11 KV |
|
Secondary Voltage |
0.4KV |
|
Winding Material |
Copper |
|
Vector Group |
Dyn11 |
|
Impedance |
4% |
|
Tap Changer |
NLTC |
|
Tapping Range |
±2*2.5% @ Primary Side |
|
Load Loss |
3.5 kW - 4.5 kW |
|
No Load Loss |
0.7 kW - 1.0 kW |
Standards & Certifications
Our 11kV dry-type transformers are fully designed, manufactured, and tested in strict compliance with the following international standards:
✔ IEC 60076-11 (Dry-type power transformers)
✔ IEEE C57.12.01 (Standard General Requirements for Dry-Type Transformers)
✔ SANS 780 (South African National Standard for Distribution Transformers)
Core Manufacturing Process
Transformer drawings
Quality Control & Testing
- Routine Testing
Every unit undergoes 100% routine testing per IEC 60076 in our ISO 9001 certified facility. A comprehensive Factory Test Report (FAT) is supplied with each transformer shipment.
- Partial Discharge Test
Routine factory testing ensures partial discharge is ≤ 10 pC at 1.3Uₘ (or 1.373Uₘ), mitigating long-term insulation degradation under continuous electrical stress.
- Sound Level Verification
Audited to confirm a 10 dB noise reduction via precision core alignment.
- Short-Circuit Impedance Test
Measures deviation within ±5% of rated impedance for proven grid stability.
- Impulse Voltage Test
Subjected to full-wave lightning impulse testing (Standard BIL up to 75 kV Peak) to validate insulation reliability against transient overvoltages.
FAQ
Q: How is the transformer protected against moisture during long-distance maritime transport?
A: Units are vacuum-sealed in heavy-duty moisture barrier bags and packed in export-grade, fumigated seaworthy wooden cases.
Q: What is the standard routine lead time for custom-engineered factory production?
A: Factory production typically requires 30 to 45 days, including routine testing and client inspection (if required) before final dispatch.
Q: How are the heavy components secured inside the shipping container to prevent transit shifting?
A: Transformers are anchored directly to container bases using 12 mm steel wire ropes/chains and custom-fit timber/steel chocks to withstand up to 1G of transit acceleration.
Q: Does the factory provide routine post-installation maintenance and diagnostic guidelines?
A:Yes, each unit ships with comprehensive manuals detailing annual infrared thermography and insulation resistance testing protocols.
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