2025-08-04
Here is a typical specification sheet outline for a 1250 kVA Transformer. Critical values depend heavily on application, voltage levels, and standards. If you need a transformer, please contact the manufacturer to obtain the exact specifications.
1. Basic Ratings:
Rated Capacity: 1250 kVA
Frequency: 50 Hz or 60 Hz (Specify)
Primary Voltage (HV): ______ kV (e.g., 11 kV, 33 kV, 13.8 kV, 34.5 kV - Must Specify)
Secondary Voltage (LV): ______ V (e.g., 400V, 415V, 480V, 690V - Must Specify)
Vector Group: ______ (e.g., Dyn11, YNd1, Dyn5 - Common depends on HV/LV & grounding)
Number of Phases: 3-Phase
2. Type & Construction:
Type: Liquid-Filled (Mineral Oil, Silicone, Ester) or Dry-Type (Vacuum Pressure Impregnated - VPI, Cast Resin - CR)
Cooling Class: (Liquid: ONAN, ONAF / Dry: AN, AF)
Enclosure: (Liquid: Tank with Radiators / Dry: IP20, IP23, IP54 - Specify)
Winding Material: Copper (Preferred for efficiency, compactness) or Aluminum
Core Material: Grain-Oriented Electrical Steel (GOES)
3. Performance Characteristics:
Impedance Voltage (Z%): Typically 4% to 6% at rated load (Specific value crucial for fault level calculation - Must Specify)
No-Load Loss (Po): ______ Watts (Typical range: 1500W - 3000W - Depends heavily on type & design)
Load Loss (Pk @ 75°C/115°C): ______ Watts (Typical range: 9500W - 14500W - Depends heavily on type & design)
Total Loss (Po + Pk): ______ Watts
Efficiency (η): ______ % (Calculated from losses, typically >98.5% at full load)
Temperature Rise: (Liquid: 55°C/65°C Oil Rise / Dry: 80°C/115°C/150°C Rise - Specify class - e.g., 65K, 80K, 115K)
Sound Level: ______ dB(A) (Measured at 1m under no-load. Typical: Liquid ~55-65 dB, Dry ~60-70 dB)
4. Taps:
On-Load Tap Changer (OLTC): Yes / No (If Yes, Range: e.g., ±10% in 1.25% steps)
Off-Load Tap Changer (DETC/ NLTC): Typically Yes (Range: e.g., ±2.5% or ±5% in 2.5% steps - Specify HV or LV side)
5. Electrical Tests:
Applied Voltage (HV): ______ kV (1 min power freq.)
Applied Voltage (LV): ______ kV (1 min power freq.)
Induced Voltage: ______ kV (2 x Rated Voltage for 60 sec / 7200 cycles)
Impulse Voltage (HV): ______ kV (BIL Level - e.g., 95kV for 11kV, 170kV for 33kV)
Impulse Voltage (LV): ______ kV (BIL Level - e.g., 10kV, 20kV)
Routine Tests: Resistance, Ratio, Polarity/Vector Group, Load Loss, No-Load Loss, Impedance, Insulation Resistance (IR), Dielectric Dissipation Factor (Tan Delta) - Oil.
Type Tests: As per standards (IEC, IEEE, etc.)
6. Standards & Compliance:
Design Standards: IEC 60076, IEEE C57.12.00 / C57.12.01, IS 2026, etc. (Specify)
Efficiency Standards: DOE 2016 (USA), EU CoC Tier, IE2/IE3/IE4 (IEC), IS 1180 (Specify applicable)
7. Physical Data:
Weight (Core & Coils): ______ kg
Weight (Oil): ______ kg (Liquid-Filled Only)
Total Weight: ______ kg (Typical range: 2500 kg - 4500 kg)
Dimensions (L x W x H): ______ mm x ______ mm x ______ mm (Highly variable)
Oil Quantity (if applicable): ______ Liters
8. Terminations:
HV Terminals: ______ (e.g., Air Insulated Bushings, Cable Boxes - Size & Type)
LV Terminals: ______ (e.g., Air Insulated Bushings, Cable Boxes - Size & Type)
Neutral Terminations: ______ (HV & LV - Size & Type)
9. Accessories & Options:
Temperature Indicators: Winding Temperature Indicator (WTI), Oil Temperature Indicator (OTI)
Protective Devices: Buchholz Relay (Liquid), Pressure Relief Device (PRD), Sudden Pressure Relay (SPR)
Monitoring: Remote Temperature Monitoring (RTD/Pt100), Oil Level Gauge, Moisture Indicator (Silica Gel)
Cooling: Fans for AF cooling (Auto/Manual control)
Dehydration Breather: Yes / No (Liquid-Filled)
Paint: Standard Color (e.g., RAL 7032) / Special Color
10. Environmental:
Ambient Temperature: -5°C to +40°C (Standard), Higher ambient available.
Altitude: Up to 1000m ASL (Standard), Derating above.
Seismic Rating: Zone ____ as per ____ standard (e.g., IEEE 693, IBC)
Fire Safety: Dry-Type Class F1 / Liquid Fire Point ____ °C (Specify fluid type)
1. HV/LV Voltages & Vector Group: These are the MOST CRITICAL specifications and must be defined for your specific application.
2. Impedance (Z%): This value is crucial for downstream protection coordination and fault current levels. Specify the required value.
3. Losses (Po & Pk): Directly impact operating cost and efficiency class. Specify maximum allowable values if critical.
4. Type (Oil/Dry): Driven by location (indoor/outdoor), fire safety requirements, environmental concerns, and maintenance capabilities.
5. Standards: Ensure compliance with local regulations and utility requirements.
6. Manufacturer Data: This sheet is a template. Always obtain detailed specifications and test reports from the transformer manufacturer for your exact requirements.
