SVC-T01 · HIGH VOLTAGE TRANSFORMER DIAGNOSTICS

Complete Transformer Testing Services in Pakistan.

TransfoLine provides end-to-end diagnostic testing for power and oil distribution transformers (25 KVA to 8000 KVA) across industrial plants, substations, and grid networks in Pakistan. Utilizing calibrated test sets from Megger, Omicron, and Fluke, our certified engineers perform comprehensive physical, electrical, and chemical diagnostics to guarantee asset reliability and compliance with IEC 60076 standards.

25 TO 8000 KVA 10 DIAGNOSTIC PROCEDURES SFRA & TTR CAPABILITY ON-SITE MOBILE UNITS
Power and distribution transformer undergoing testing in Lahore Pakistan
CAPACITY RANGE
25–8000 KVA
STANDARDS COMPLIANCE
IEC 60076
REPORT TURNAROUND
24 Hours
01
  EXECUTIVE SUMMARY

What is Transformer Testing?

Transformer testing is an essential engineering procedure combining electrical, dielectric, magnetic, and thermal diagnostics to assess the internal health, winding geometry, ratio accuracy, and oil quality of power and distribution transformers. It verifies that new, refurbished, or in-service transformers withstand operational electrical stresses without failure or unexpected tripping.

02
  PROCEDURES

The 10 Diagnostic Tests We Perform

TT.01 Insulation Resistance & PI Test (Megger) Measures dielectric resistance (HT-LT, HT-E, LT-E) up to 10kV with Polarization Index calculation to detect winding contamination and moisture. Dielectric Health
TT.02 Turns Ratio (TTR) & Vector Group Verification Verifies primary-to-secondary voltage transformation ratio across all tap positions within ±0.5% tolerance and confirms vector group phase relationship. Ratio & Phase
TT.03 Winding Resistance Measurement Micro-ohm measurement across all phases and tap changer positions to detect loose internal connections, broken strands, or tap changer contact wear. Conductive Integrity
TT.04 Sweep Frequency Response Analysis (SFRA) Frequency fingerprint analysis to detect core shifts, mechanical winding deformation, or clamping failure following transport or high-current faults. Mechanical Structure
TT.05 Transformer Oil Dielectric Strength (BDV Test) Breakdown voltage test across a calibrated 2.5 mm electrode gap per IEC 60156 to ensure insulating oil can withstand operating dielectric stress. Oil Quality
TT.06 Excitation Current & Magnetic Balance Test Applies low voltage to detect shorted turns, core magnetic asymmetry, and inter-turn insulation faults before full energization. Core & Turns
TT.07 Power Factor / Tan Delta (δ) Testing Measures dielectric dissipation factor and capacitance of windings and bushings to evaluate overall insulation aging and moisture content. Dielectric Loss
TT.08 Load & No-Load Loss Measurement Evaluates copper losses and core iron losses to determine transformer efficiency, temperature rise profile, and compliance with WAPDA/DISCO specs. Efficiency & Loss
TT.09 Impedance Voltage & Short Circuit Test Calculates percentage impedance (%Z) to verify short-circuit withstand capability and ensure proper fault current limiting. Impedance Check
TT.10 Moisture & Insulation Dehydration Diagnostics Comprehensive assessment of solid insulation moisture percentage to determine whether vacuum dehydration and filtration are required. Dehydration Check
03
  DIAGNOSTIC MATRIX

Testing Frequency & Recommended Actions

Test Name Primary Purpose Recommended Interval Trigger for Action
Insulation Resistance (IR) Detect moisture, carbonization & aging Annual / Pre-commissioning < 100 MΩ or PI < 1.5
Turns Ratio (TTR) Identify shorted turns & ratio error Commissioning / After trip Deviation > ±0.5%
Oil Dielectric BDV Measure oil insulation strength Every 6 to 12 months < 35 kV breakdown
Winding Resistance Detect loose joints & tap wear Every 2 years / Pre-commission > 2% phase unbalance
SFRA Analysis Check core/winding mechanical shift After heavy fault / relocation Curve deviation from baseline
04   TRANSFORMER TESTING FAQ

Frequently Asked Questions.

Clear answers regarding transformer testing from our engineering staff.

FREQUENCY How often should an industrial transformer be tested?

We recommend annual insulation resistance and oil BDV testing for distribution units, and 6-monthly oil analysis for large power transformers (500+ KVA) operating under high industrial load.

ON-SITE Can you test large transformers without removing them?

Yes. Our senior testing engineers bring fully calibrated portable test equipment directly to your site, executing all electrical, dielectric, and oil tests without removing the transformer.

REPAIR What if a transformer fails the test?

TransfoLine operates a dedicated 18-year transformer manufacturing and repair facility. If your unit shows low oil BDV, we perform on-site oil dehydration; if windings are degraded, we offer complete rewinding and warranty repair.

06
  GET STARTED

Book a Transformer Test.

Schedule on-site diagnostics or request quote within 2 hours.

Need immediate transformer diagnosis, oil testing, or pre-commissioning testing? Contact us directly.

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