Sweep Frequency Response Analysis is used for testing the integrity of power transformers after transportation or following the occurrence of high currents (typically system faults). This is done by measuring the electrical transfer function over a wide frequency range to record a fingerprint of the transformer under test. Typically, a baseline is taken in the factory to which all subsequent test results are compared.

It detects winding defects and faults in the magnetic core - thereby helping to improve transformer reliability, reduce maintenance costs and prevent costly failures.


SFRA is used for transformer testing, after:

  • a short circuit event
  • transport
  • occurrence of high transient fault currents
  • a significant change in the monitored values (e.g. combustible gases) or a safety shutdown

The following test regimes can also be performed:

  • Routine transformer condition measurement
  • Verification of unusual events determined during conventional testing


If you require SFRA testing, call Megavar for professional service and advice.