Title :
Aging degree evaluation for paper-oil insulation using the recovery voltage method
Author_Institution :
Fac. of Electr. Eng., Opole Univ. of Technol., Opole, Poland
fDate :
10/1/2015 12:00:00 AM
Abstract :
The paper presents new diagnostic method applied to assess aging degree for paper-oil insulation used in professional electrical power device, primarily including medium and high power transformers. The described method is based on modified diagnostics using the recovery voltage effect occurring in dielectrics (RVM - Recovery Voltage Methods). Modification of the RVM method applied so far, which is now used only to assess moistening degree for paper-oil insulation in power transformers, consists in a new parametric analysis of recovery voltage time characteristics. Simulation and experimental tests carried out in laboratory conditions for adequately prepared insulation samples have proven that the time-constant of recovery voltage decay (τR_MIN) is the most susceptible parameter as regards quantitative change in the function of aging of the examined insulation. This conclusion is also confirmed by statistical studies, in which a multi-parameter variance analysis method has been applied. An original equivalent circuit diagram of the insulation has been used to simulate aging degree of paper-oil insulation samples in numerical tests. The diagram is based on the Cole-Cole type dielectric response model.
Keywords :
equivalent circuits; paper; power transformer insulation; transformer oil; Cole-Cole type dielectric response model; RVM; aging degree evaluation; equivalent circuit diagram; multi-parameter variance analysis method; paper-oil insulation; power transformers; recovery voltage decay; recovery voltage method; Aging; Approximation methods; Dielectrics; Impedance; Insulation; Integrated circuit modeling; Mathematical model; Power transformer insulation testing; aging; dielectricpolarization; moisture; paper insulation; relaxation methods;
Journal_Title :
Dielectrics and Electrical Insulation, IEEE Transactions on
DOI :
10.1109/TDEI.2015.004796