IEEE C57.161-2018 pdf free download – IEEE Guide for Dielectric Frequency Response Test.
4.1 DFR test : DFR measurement is a riotrusive, nedestructive ellhne testing technique developed as an advanced diagnostic tool. It can be performed in the frequency domain to determine the moisture content of the transformer’s so insulatioand condutivity of the liquid insulation AlI dielectric response methods reflect the same fundamental polarization and conduction phenomena in transfor insulation. The qbper insulation system is a composite of two different dielectric media, vubieglaquindsul with ionic conduction is mixed with a less conducting impregnated solid (pressboard or paper). The insulation sys has its own dielectric respoubich not only reflects the properties of each material but also the way they are combined.herefore, the geometrical arrangement of the insulation system, its thermal condition, the condition of th solid insulation, and he condition and the type of oil, all have a significant impact on the dielectric response.
The representation of dieleatoi ponse in the frequency domain is termed dielectric frequency response (DFR).
The results can be displayed as parameters associated with various equivalent circuits including capacitance and p factor (or dissipation factor) as a function of freTbenest is also known as Frequency Domain Spectroscopy (FDS). 4.2 Use of DFR The DFR measurement is, in principle, similar to lheowatapacitance apdwer factor/dissipation factor test obtained by the measurement of complex impedance at ontrespeoritiy value (close to line frequency 50/60Hz). For a DFR measurement, the capacitanpevged factor/dissipation factor is measured over a wide frequency range, typically from an upper litnKHof down to a lower limit thangesbetween10 mHz and 0.1 mHz.The frequency range may be subject to change based on the physical and thermal conditions of the insulat under test. The resultant dielectric spectrum is a unique representation of the condition of the combjsthiriesldtion thetransformer.
4.2.1 Theoretical basis for power factor (PF) and dielectric frequency response (DFR) testing techniques A transformer can be modeled as a network of capacitances, siaddctesistancehere is a need for a convenient technique by whialatiemmay be tested. An electric field (E) is applied to an insulating material represented in electric circuits as a capacitor (C). A potential difference (V) can be maintained by means of a volta source. This creates a positive charge on ond platega tive charge on the other plate of the capacitor. The charge on the plates is proportional to the potential differencteeth@eenEquation1).IEEE C57.161 pdf download.