Abstract:
Frequency response analysis (FRA) is a powerful and sensitive tool to assess the core, windings and
clamping structures within a power transformer, In this thesis, a Low-Cost Frequency Response
Analyzer (LCFRA) is presented. The developed LCFRA composed of a digital oscilloscope, a
function generator and Labview software. In this thesis, the accuracy and efficiency ofLCFRA was
provedby 3 measurement cases. Firstly, the frequency response of basic electrical circuit elements,
resistor, inductor and capacitor, was measured by LCFRA. Then the result was compared with that
obtained from simulation using Multisim software. Secondly, the frequency response of the
transformer measured by the LCFRA was compared with that from a commercial FRA (DOBLE
M5300). Lastly, the frequency response of the transformer was measured by the LCFRA with the
designed coaxial cables whoseits characteristics was compared with the measurement obtained from
commercial coaxial cables.In the first and second cases, therelation wascorrelated by the cross
correlation coefficients (CCF) which had the minimum values of O.95863 and 0.95384, respectively,
which showed a good match between those measuring results. Finally, the last case was proved by
relative factor and CCF following the recommendation of THE CHINESE STANDARD DL
911/2004 and IEEE-PC 57.149. The minimum values of relative factor in each frequency band and
CCF were RLF = 2.455, RMF = 1.724,RHF = 0.748 and CCF = 0.98446, respectively.Thisindicates
that the designed coaxial cable gave a good test result.