Determination of individual values of four-element equivalent circuits elements parameters at technical diagnostics of insulation by absorption methods

The aim of this article is to present a methodology of determining of the individual values of the parameters of four-element equivalent circuits for insulation with through conductivity. Methodology. The proposed method consists in the fact that at a time interval of more than 10 s, when the charge indicator no longer contributes to the leakage current, three points t1, t2 and t3 are selected, such that t2 – t1 = t3 – t2. To be able to determine the absorption coefficient R60/R15, it is recommended to take t1 = 15 s, t2 = 37.5 s and t3 = 60 s. At the same time, by subtracting I(t2) – I(t1) and I(t3) – I(t2), the constant component of the absorption curve is excluded and it becomes possible to determine the individual values of the parameters of the generalized equivalent circuit of insulation, additionally using its conductivity in operator form. Results. As calculations show, the correct determination of the parameters of insulation equivalent circuit according to the proposed method is possible only with a certain ratio of these parameters. The charge time of the geometric capacitance Cg(R0+Rd), where R0 and Rd are the resistance that forms the charging exponent, and the resistance of the sensor, should be within 0.2 s