The IDAX300 and IDAX350 insulation diagnostic analysers are insulation diagnostic instruments based on DFR (Dielectric Frequency Response), also known as FDS (Frequency Domain Spectroscopy). DFR is a measurement technique in which capacitance and losses (dissipation factor/tan delta or power factor) is measured over multiple frequencies to assess insulation condition in test objects such as power transformers, bushings, and instrument transformers. DFR technology is an established test procedure in laboratories that Megger has adapted for field use in the IDAX range of instruments.
This IDAX series consists of:
For extended applications, the IDAX interfaces seamlessly with the VAX020 high voltage amplifier for 2 kV.
In these instruments, the IDAX software incorporates a new ITC corrected frequency sweep specifically designed for assessment of instrument transformers and bushings. Thanks to a novel approach to the combination of time and frequency domain data, the IDAX provides the shortest measurement time in the marketplace for a full DFR measurement from 1 kHz to 10 μHz. Separate reference models are fitted to each data set (time or frequency) prior to transformation and combination, which eliminates the risk of artifacts introduced by approximations or transformation of incomplete data sets.
The IDAX is exceedingly easy to use with an automated test flow and presentation of results in an easy to understand 'traffic light' colours. The IDAX DFR method is now part of international guides and standards e.g., Cigre TB 254, Cigre TB 414, Cigre TB 445, Cigre TB 775, IEEE C57.152-2013, IEEE C57.161-2018.