Transformer Diagnostic Testing
Power transformers represent one of the largest capital investments in any substation. Extending their operational life while minimizing failure risk requires a structured programme of electrical diagnostic tests. VA-TEK transformer test instruments support every phase of the transformer lifecycle.
Lifecycle Phases
Factory Acceptance Testing
Baseline electrical measurements taken during FAT — turns ratio, winding resistance, excitation current, insulation resistance and SFRA — establish the reference signature for each new transformer, so that any subsequent change can be attributed with confidence.
Transportation and Installation
Transport and handling can displace windings and core clamping without leaving any external sign. Repeating the ratio, winding resistance and SFRA tests after delivery and comparing them against the factory baseline is the standard method of confirming the transformer arrived undamaged.
Commissioning
Before energization, a full electrical test programme verifies winding integrity, insulation condition and tap changer operation. Combined with protection relay testing, it confirms the transformer and its protection scheme will operate correctly from day one.
Periodic Maintenance
Trending insulation resistance, polarization index, winding resistance and insulation power factor over the life of the asset reveals progressive insulation ageing and deteriorating tap changer contacts long before they become a failure risk.
Post-Fault Assessment
After a through-fault or a sudden pressure relay operation, SFRA and turns ratio testing identify winding deformation or displacement that resistance and ratio tests alone may miss — informing the run / repair / replace decision.
End-of-Life Assessment
When a transformer approaches the end of its design life, electrical diagnostic data combined with oil quality results and an internal inspection supports a defensible condition assessment and capital replacement plan.