News

New Hipot! – 300kV Resonant Test Set

Megavar customers will shortly see a new piece of kit in the online Megavar showroom that is available for hire with one of our specialist technicians.  Megavar has recently procured a 300kV AC resonant test set which is a smaller version of our 500kV test set.  Our new hipot specialises in testing transformers, generators and cables from 0 to 300kV at resonant frequency (frequency capability is 30-300Hz).  It has performed well to date, delivering excellent performance for our testing engineers at Wheatstone and Ichthys LNG sites, recently.  Currently, Megavar is using the new hipot to perform HV Resonance testing to verify the integrity of the 132 kV power cables after installation in the Northern Territory.

Advantages of resonant test systems:

  • Reduced input power requirements.
  • Since the circuit utilises a tuned circuit at the power frequency, a pure sine wave, without harmonica appears across the test sample.
  • No power follow-up occurs as a result of test failure. The impedance of a normal test transformer is approximately 10%. When a failure occurs at full voltage, the inrush current can be as high as ten times the rated current until the overload devices trip the unit off. During this trip out period the test transformer and load may see peak voltages as high as twice the initial test voltage, in addition to the higher currents.

Megavar prides itself on great service and highly competitive offerings and welcomes all enquiries about the new addition to our test gear stable.