Transformer Tests

 Transformer Tests

Transformer Testing Used equipment:

1.1 Insulation Resistance Test (Megger Test)

 • Purpose: Checks insulation health between windings and ground.

 • Instrument Used: Megger (Insulation Resistance Tester)

 • Test Voltage:

 • LV Winding: 500V – 1000V

 • HV Winding: 2500V – 5000V

1.2 Transformer Turns Ratio (TTR) Test

 • Purpose: Ensures correct turn ratio between primary and secondary.

 • Instrument Used: TTR Meter (Transformer Turns Ratio Tester)

 • Acceptable Range: ±0.5% of design ratio

1.3 Winding Resistance Test

 • Purpose: Measures resistance of windings to detect loose connections or damage.

 • Instrument Used: Micro-Ohmmeter / DC Resistance Tester

 • Test Current: 1A – 10A DC

1.4 Vector Group Test

 • Purpose: Confirms correct vector group and phase displacement.

 • Instrument Used: Phase Angle Meter & TTR Meter

1.5 No-Load Loss and Current Test

 • Purpose: Measures core losses at rated voltage.

 • Instrument Used:

 • Power Analyzer

 • Voltmeter & Ammeter

1.6 Load Loss and Impedance Test

 • Purpose: Measures copper losses and impedance voltage.

 • Instrument Used:

 • Power Analyzer

 • High-Voltage Source

1.7 Oil Dielectric Strength Test

 • Purpose: Checks insulation quality of transformer oil.

 • Instrument Used: BDV (Breakdown Voltage) Tester

 • Standard Value: Minimum 30 kV for new oil

1.8 Magnetic Balance Test

 • Purpose: Ensures uniform flux distribution in three-phase transformers.

 • Instrument Used: Multimeter & Variac (Variable Voltage Supply)

2. Type Tests (Performed on One Unit per Batch)

2.1 Short Circuit Test (Dynamic & Thermal Stability Test)

 • Purpose: Verifies the transformer’s ability to withstand fault conditions.

 • Instrument Used: High-Power Short Circuit Test Setup

2.2 Lightning Impulse Test

 • Purpose: Simulates lightning strikes to check dielectric strength.

 • Instrument Used:

 • Impulse Generator

 • Oscilloscope

2.3 Temperature Rise Test

 • Purpose: Measures winding and oil temperature rise during full load.

 • Instrument Used:

 • Thermocouples

 • IR Camera

3. Special Tests (As per Customer Request)

3.1 Partial Discharge Test

 • Purpose: Detects internal insulation defects.

 • Instrument Used: Partial Discharge Detector

3.2 Sweep Frequency Response Analysis (SFRA) Test

 • Purpose: Detects winding displacement or mechanical deformation.

 • Instrument Used: SFRA Analyzer

3.3 Frequency Response Analysis (FRA) Test

 • Purpose: Checks mechanical integrity of windings.

 • Instrument Used: Frequency Response Analyzer