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6.3 MVA （6300kva) ）10kV/0.4kV Three-Phase Oil-Immersed Transformer | Global Procurement Guide

Name: 6.3 MVA （6300kva) ）10kV/0.4kV Three-Phase Oil-Immersed Transformer | Global Procurement Guide
Brand: HENGFENGYOU
SKU: HFY-1371

I. Overview of 6.3 MVA 10kV/0.4kV Power Transformer

The 6.3 MVA (6300 kVA) three-phase oil-immersed power transformer represents a critical capacity threshold in medium-voltage distribution networks. Positioned between standard distribution units and large power transformers, this 6.3 MVA model serves as the backbone for regional substations, heavy industrial zones, and large-scale renewable energy integration points. It is engineered to reliably step down primary distribution voltages (e.g., 10 kV, 11 kV, or 13.8 kV) to standardized utilization voltages (typically 0.4 kV or 480 V).

Built to the highest international benchmarks—including IEC 60076, GB/T 6451, GOST, and ANSI/IEEE C57.12.00—Hengfengyou Electric manufactures each 6.3 MVA transformer using high-grade CRGO silicon steel cores and oxygen-free copper windings. With proven field performance across more than 50 countries—spanning Russia, Central Asia (Kazakhstan, Uzbekistan, Tajikistan, Turkmenistan, Kyrgyzstan), Eastern Europe (Belarus, Ukraine), and Southeast Asia (Vietnam)—this transformer has earned a reputation for uncompromising reliability under harsh grid conditions.

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Transformer Specifications

Manufacturer

HENGFENGYOU ELECTRIC

Standard on which performance data is based

IEC 60076,GB 1094-1996,GB/ T6451-2008,GB/T 7597-2007

Type

OIL IMMERSED

Method of Cooling

ONAN, ONAF, OFAF, OFWF, ODAF, ODWF

Rated Power

6300 KVA

Voltage Ratio

10kv/0.4kv

Frequency

50/60HZ

Tap Changer

HV·Tapping

±2.5%;±5%

Vector Group

Dyn11 or Yyn0

Core Material

CRGO Steel

Winding Material

Alumnium or Copper

No Load Losses (GB/T S13 series)

480w

Load Losses (GB/T S13 series)

5150w

Dimensions of Transformer

II. Product Structure Options for 6.3 MVA Transformers

Given the substantial power throughput of a 6.3 MVA unit, Hengfengyou Electric offers tailored structural configurations to match specific installation environments and operational demands:

Configuration	Typical Application	Key Feature
6.3 MVA Three-Phase Oil-Immersed Transformer (6 kV – 35 kV)	Utility substations, industrial parks, mining operations	Robust corrugated tank or radiator panel cooling; ONAN or ONAF options
6.3 MVA Epoxy Resin Cast Dry-Type Transformer (6 kV – 35 kV)	Indoor commercial centers, hospitals, data centers	Zero oil leak risk, self-extinguishing, high fire safety rating
6.3 MVA Pad-Mounted Transformer Substation (2.4 kV – 34.5 kV)	Urban distribution, gated communities, public infrastructure	Compact, tamper-proof, fully integrated HV/LV switchgear

Key Differentiator for 6.3 MVA: At this capacity, ONAF (forced air cooling) becomes a practical standard option, boosting nominal output by up to 33% during peak demand without requiring a larger physical footprint.

III. Core Technical Advantages & Value Proposition

Ultra-High Efficiency Exceeding 99%: The 6.3 MVA transformer achieves operating efficiencies surpassing 99%, fully compliant with European Ecodes Directive 2015/2014/548/EC Tier 2 and equivalent local standards. This translates into measurable annual energy savings—often recovering the capital cost differential within 3–5 years of continuous operation.
Hermetically Sealed, Truly Maintenance-Free Design (IP65): The tank is fully welded and sealed against moisture ingress and atmospheric oxidation. This eliminates the need for periodic oil testing, desiccant replacement, or conservator maintenance. Designed for a service life exceeding 25 years with zero scheduled oil intervention.
Superior Overload Capability for Industrial Duty Cycles: Copper-wound models permit short-term overloads up to 150% of rated capacity for up to 2 hours. This is particularly valuable for industries with intermittent heavy loads (e.g., crushers, compressors, arc furnaces) where momentary surges are unavoidable. Continuous oil temperature monitoring (top oil ≤ 95°C) is recommended.
Eco-Responsible Engineering: Optional filling with FR3 Natural Ester Fluid offers enhanced fire safety (high fire point > 300°C), superior insulation longevity (up to 5–8 times longer paper life vs. mineral oil), and full biodegradability—supporting LEED and other green certification goals.
Multi-Standard Certifications: Fully certified to ISO 9001, CE, IEC, SABS, COC, CSA, and UL, enabling seamless import clearance and regulatory acceptance across target markets.

IV. Price Factors & Industrial Procurement Strategy

The total cost of ownership (TCO) for a 6.3 MVA transformer extends far beyond the purchase price. As a direct manufacturer, Hengfengyou provides transparent pricing driven by these key factors:

Factor	Impact on Price	Recommendation
Winding Material	Copper ≈ +20–30% vs. Aluminum	Choose copper for lowest load losses, higher short-circuit withstand, and longest lifespan
Cooling System	ONAF adds ~8–12% over ONAN	Specify ONAF if peak loads exceed 80% of rating for >4 hours/day
Tap Changer Type	OLTC adds ~15–25% over OCTC	Select OLTC only if voltage regulation is required under load (e.g., weak grids)
Accessory Level	Advanced monitoring adds ~5–10%	Include WTI, OTI, and Buchholz relay for critical installations
Metal Market Index	Variable (weekly update)	Request a firm quote valid for 15 days to lock in current copper/steel prices

Request an Instant 6.3 MVA Power Transformer Price Quote

V. Frequently Asked Questions (FAQ) — Tailored for 6.3 MVA Specific Pain Points

Q1: What makes the 6.3 MVA transformer different from smaller ratings like 3.15 MVA?

Beyond double the capacity, the 6.3 MVA unit requires significantly larger cooling surfaces, often necessitating radiator panels instead of simple corrugated tanks. It also demands higher-rated bushings, larger cable boxes, and more robust foundation anchoring due to increased weight (total weight typically 8–12 tons depending on design). The short-circuit forces at 6.3 MVA are substantially higher, demanding reinforced winding clamping structures.

Q2: My facility experiences frequent voltage sags. Can this transformer handle them?

Yes—provided you specify the On-Load Tap Changer (OLTC) option. A standard Off-Circuit Tap Changer (OCTC) requires de-energizing the transformer to adjust taps. For facilities with ±10% voltage fluctuations (common in remote industrial zones), an OLTC enables real-time voltage regulation without interrupting production.

Q3: What is the typical transport weight and dimension for a 6.3 MVA unit?

A standard 6.3 MVA 10/0.4 kV oil-immersed transformer weighs approximately 9,500–12,000 kg (filled) and occupies roughly 2.8m (L) x 1.8m (W) x 2.5m (H) . This requires flatbed truck or open-top container shipping. We provide detailed packing diagrams and lifting lug positions for safe handling.

Q4: How do I calculate the expected no-load and load losses for budgeting purposes?

For a typical Tier 2-compliant 6.3 MVA transformer:

No-load loss (iron loss): Approximately 6.0–7.5 kW
Load loss (copper loss at 100% load): Approximately 38–45 kW

These values directly affect your annual electricity bill. We provide guaranteed loss figures in our technical datasheet for your financial modeling.

Q5: What is the maximum ambient temperature for reliable operation?

The standard design ambient temperature range is -25°C to +40°C. For deployments in extreme climates—such as Central Asian deserts (+50°C) or Siberian winters (-40°C)—we offer tropicalized insulation and low-temperature oil grades as optional upgrades.

Q6: Can I parallel two 6.3 MVA transformers for redundancy?

Yes, paralleling is possible and common for N+1 redundancy in critical facilities. Requirements include:

Identical vector group (Dyn11 is standard)
Voltage ratio matching within ±0.5%
Impedance voltage (Z%) within ±10% of each other
Same tap position setting

We provide impedance matching reports upon request for parallel operation planning.

Q7: What is the recommended preventive maintenance schedule for a 6.3 MVA unit?

Due to the hermetically sealed design, maintenance intervals are extended:

Monthly: Visual oil level check, temperature log review
Quarterly: Infrared thermography of bushing connections
Annually: Insulation resistance (IR) test, DGA (Dissolved Gas Analysis) sampling
Every 3 years: Full oil dielectric test, winding resistance measurement
Every 10 years: Internal inspection (if access port exists)

Q8: How do I verify that the delivered transformer meets my specified efficiency tier?

Each transformer ships with a certified test report showing measured no-load loss, load loss, and impedance voltage. For Tier 2 compliance, we also provide a declaration of conformity referencing the applicable EU directive. Third-party witness testing (e.g., by SGS or Bureau Veritas) can be arranged at additional cost.

Q9: What happens if I need to relocate the transformer after initial installation?

Relocation is feasible but requires:

Complete draining of insulating oil (approx. 2,500–3,000 liters for 6.3 MVA)
Disconnection of all HV/LV cables and accessories
Professional lifting using rated spreader beams
Re-filling and vacuum oil treatment at the new site

We recommend factory supervision for any re-installation to maintain warranty validity.

Q10: Do you offer financing or leasing options for large transformer purchases?

For qualified buyers, we partner with trade finance institutions to offer:

Letter of Credit (L/C) at sight or usance
Partial shipment allowed for multi-unit orders
Deferred payment terms (up to 180 days) for established clients

Please contact our sales team with your project details for a customized commercial proposal.

Grow Your Business with Hengfengyou Electric

Our mission is to become the world's preferred manufacturer of medium-to-large power transformers. Decades of accumulated engineering expertise have empowered customers in over 50 countries to build resilient, efficient electrical infrastructure. Once our clients partner with us, they stay—because Hengfengyou consistently delivers the highest quality products, on-time shipments, and responsive after-sales support.

Contact us today to discuss your 6.3 MVA transformer requirements.

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