The 400 kVA Dry Transformer is designed for the modernization of the 6.3 kV and 20 kV CHE Scropoasa substation. This high-performance, three-phase transformer operates without protective casing and features a durable, maintenance-free construction, ideal for supplying 0.4 kV AC services in a 50 Hz environment.
Key Specifications:
Power Rating: 400 kVA
Voltages:
6.3 kV Model: Primary 6.3 kV / Secondary 0.4 kV
20 kV Model: Primary 20 kV / Secondary 0.4 kV
Cooling System: Natural air circulation
Temperature Class:According to SR EN 60076-3
Maximum Winding Overtemperature: 100°C
Noise Intensity: 63 dB
Insulation: Epoxy resin and quartz powder blend for maintenance-free operation, moisture resistance, and fire safety.
Core: Low-loss cold-rolled silicon steel with high magnetic permeability and low hysteresis and eddy current losses.
Windings: Copper with epoxy resin insulation; high mechanical strength against short-circuit forces.
Technical Features:
Connection: Dyn-5
Adjustment: 5-step voltage adjustment with ±2x2.5% range on the high voltage side, performed in the absence of voltage.
Insulation Level: F
Environmental Conditions:
Maximum Ambient Temperature: +40°C
Minimum Ambient Temperature: -30°C
Altitude: <1200 meters
Humidity: <100% at 20°C
Seismicity: 760±15 mmHg
Accessories:
Trolley: With bidirectional wheels and a wheel locking device
Temperature Sensors: At least 3 PT100
Temperature Control Unit: Integrated into the protection, signaling, and monitoring system
Lifting Lugs: For easy handling
Neutral Terminal: Accessible on the low voltage side for the 400 kVA, 6.3/0.4 kV transformer
Compliance:
Standards: EN 60076. CEI 60076 series, IEC 60185. DIN-VDE 0414-1
ECO Design Directive: Compliant with 548/2014 and subsequent amendments
Operational Flexibility:
Overload Capability:
10% overload for 1 hour
20% overload for 30 minutes
30% overload for 15 minutes
40% overload for 8 minutes
50% overload for 4 minutes
Overexcitation Tolerance: Capable of operating with a 5% maximum deviation from nominal voltage and frequency.
Testing
All transformers undergo rigorous factory testing, including:
Verification of transformation ratio
Connection group checking
Winding resistance measurement
Insulation resistance and absorption coefficient testing
Dielectric loss angle tangent measurement
Applied voltage and induced voltage tests
Measurement of no-load and short-circuit losses
Winding overheating and homopolar impedance measurement
Noise level assessment
Dielectric rigidity of the oil
