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Fire Safe Epoxy Resin 315kVA 20/0.38kV Dry Type Distribution Transformer for High Density Urban Infrastructure

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Product Description
Fire Safe Epoxy Resin 315kVA 20/0.38kV Dry Type Distribution Transformer for High Density Urban Infrastructure
Product Overview
315kVA epoxy resin dry type distribution transformer installation

This 315kVA three-phase epoxy resin dry type distribution transformer provides a secure and efficient medium-voltage power delivery solution for modern built environments. Rated at 20kV on the primary side and 0.38kV on the secondary, it eliminates the fire and leakage risks associated with liquid-filled units, making it the preferred choice for densely populated urban centers, commercial high-rises, mixed-use developments, and expanding industrial estates.

The cast resin encapsulation grants the windings outstanding resistance to moisture, chemical vapors, and thermal stress, ensuring stable operation even in coastal or high-humidity climate zones. With low partial discharge values and a proven loss profile, this transformer supports utilities, EPC contractors, and facility owners seeking long service life with minimal intervention.

Key Advantages
  • Inherent Fire Safety and Self-Extinguishing Resin: The epoxy resin insulation system is flame retardant and does not produce toxic fumes under thermal duress. This removes the need for costly fire vaults or fire suppression systems, directly aligning with building codes for indoor installation.
  • Climate-Resilient Moisture and Salt Fog Protection: Sealed cast resin windings block ambient humidity and saline air ingress, preventing surface tracking and dielectric degradation. The transformer thrives in coastal zones and high precipitation regions without supplemental dehumidification.
  • Superior Energy Efficiency and Low Partial Discharge: Low no-load and load losses meet or surpass local high-efficiency grade thresholds. The controlled manufacturing process yields extremely low partial discharge levels, preserving insulation life over decades.
  • Maintenance-Free Operation and Condition Monitoring: No oil sampling, no leak checks, no liquid disposal. An integrated temperature control unit with PT100 sensors continuously monitors winding and core temperatures, triggering cooling fans and alarms for truly unattended reliability.
  • Compact Footprint and Flexible Installation: The small physical envelope and optional IP enclosure ratings allow the unit to be placed directly at the load center, inside basements or electrical rooms. This reduces secondary cable runs, lowers installation costs, and frees up valuable real estate.
Internal view of epoxy resin transformer windings
Technical Specifications
Parameter Specification / Detail
Rated Capacity 315 kVA
Voltage Ratio 20 kV / 0.38 kV (3-phase, 50 Hz)
Vector Group Dyn11 (standard) or Yyn0 on request
Cooling Method AN (natural air) / AF (forced air, with fan kit)
Insulation Class F (155°C) with temperature rise limit class H (180°C)
Insulation Medium Class H epoxy resin cast under vacuum
Partial Discharge ≤10 pC at rated voltage
Tapping Range ±2*2.5% off-circuit tap changer (HV side)
Sound Level ≤ 52 dB(A) (AN, at 1 m, IEC 60076-11 compliant)
Protection Degree IP00 indoor; optional IP23, IP43, IP54 weatherproof enclosures
Thermal Protection Embedded PT100 temperature sensors with smart controller (alarm and trip setpoints)
Standards IEC 60076-11, IEC 60076-1, ISO 9001, applicable national grid access specifications
Altitude ≤1000 m asl (customized designs for higher elevations)
Finish Rust-proof galvanized steel or stainless steel fasteners with weather-resistant paint

Core and conductor materials are selected to meet project-specific specifications: high-permeability grain-oriented silicon steel minimizes losses, while copper or aluminum windings are precisely wound and cast to ensure uniform insulation thickness and mechanical short-circuit strength.

Transformer technical diagram and specifications
Application Solutions and Design Measures
Hot and Humid Coastal Climates

Difficulty the design addresses: Persistent high relative humidity and salt mist accelerate corrosion and cause internal condensation in ordinary transformers.

Implemented solution: The winding is completely encapsulated in hydrophobic epoxy resin without air voids. Stainless steel fixings and anti-corrosion surface treatment protect the frame. An optional anti-condensation space heater inside the enclosure prevents moisture build-up when the transformer is idle.

Continuous Urban Densification and High-Rise Buildings

Difficulty the design addresses: Urban cores require silent, fireproof equipment that can fit inside limited floor areas and comply with stringent life safety regulations.

Implemented solution: The self-extinguishing cast resin system achieves F1 flammability class (IEC) and generates negligible smoke. The magnetic core is optimized to keep sound power low, meeting noise limits acceptable for residential and office adjacency. Vertical or horizontal air ducting can be customized for building-specific ventilation layouts.

Rapid Industrial Park Expansion and Production Loads

Difficulty the design addresses: Frequent motor starts, variable process loads, and fast-track construction timelines place demands on electrical resilience and commissioning speed.

Implemented solution: The winding's high mechanical strength withstands inrush currents and short-circuit forces without deformation. The transformer is delivered factory-tested and ready to connect, cutting on-site construction time. Forced air cooling (AF mode) can temporarily increase available capacity to manage production peaks.

Remote and Semi-Attended Distribution Sites

Difficulty the design addresses: Substations in distant infrastructure corridors or islanded grids may lack routine maintenance crews.

Implemented solution: The absence of liquid dielectric removes bush-clearing and containment requirements. The digital temperature controller with RS485 communication can relay real-time status to a SCADA system, enabling remote monitoring and alarm management for EPC integrators.

Frequently Asked Questions
Q1: How does the cast resin transformer resist humidity and salt damage in tropical seaside installations?
Epoxy resin is non-hygroscopic and forms a solid, void-free insulation layer around the windings. Combined with stainless steel structural components and anti-corrosion finish, the unit resists salt fog and high moisture without the need for oil regeneration or vacuum drying on site.
Q2: Is this 315kVA transformer suitable for installation inside a commercial high-rise or a basement electrical room?
Yes. The fire-safe, self-extinguishing insulation and low smoke characteristic meet strict safety codes for indoor human-occupied buildings. Its compact design and AN cooling allow installation in ventilated basements without heavy oil-containment infrastructure.
Q3: What standard low-voltage output does the 20/0.38kV rating deliver?
The secondary voltage of 0.38kV (line-to-line) provides a standard 220V line-to-neutral power supply at 50Hz, matching typical mixed-use building distribution and industrial auxiliary power requirements in many markets.
Q4: Can the transformer handle small overloads during peak hours in an expanding industrial estate?
The Class F insulation with Class H temperature rise margin provides inherent thermal reserve. When equipped with forced air cooling fans, the unit can operate at a higher capacity for limited periods, subject to ambient conditions and duty cycle.
Q5: What maintenance activities are needed for a dry-type unit in a humid environment?
Periodic visual inspection, cleaning of ventilating grills, and verification of the cooling fan and temperature controller operation are all that is typically required. The cast resin windings themselves need no dielectric fluid testing. An optional standstill heater guarantees insulation resistance even after prolonged shutdowns.
Q6: Is this transformer capable of direct connection to a 20kV underground cable network in a dense urban setting?
Absolutely. The HV terminal arrangement can be designed with plug-in type bushings or cable boxes to accept standard 20kV XLPE underground cables, ensuring a safe, touch-proof termination inside compact urban substations.
Engineering team consultation for transformer solutions
Get in touch with our engineering team for a tailored dry-type transformer solution that matches your urban or industrial project specifications.
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Company Hunan Hentg Power Electric Technology Co., Ltd.
Location Room905, D6 building, CCSP Industrial Park, Yuelu District, Changsha,Hunan province, China
Contact Person Ms. Laurel

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