TRANSFORMATÖR YAĞI REFRAKTİF ENDEKSİ İLE KIRILMA GERİLİMİ ARASINDAKİ İLİŞKİNİN ARAŞTIRILMASI

Thedielectric strength, or breakdown voltage, of transformer oil measures itsability to support non-defective electrical voltage. Since these oils mustinsulate under high electrical potential, a significant reduction in dielectricstrength means that the oil will no longer perform. A decrease in dielectricstrength may be due to the presence of contaminants such as water, conductiveparticles, oil degradation by-products, residues, and cellulose paperbreakdown. Dielectric strength can be determined relatively simply by applyingan increasing proportion of AC voltage between two electrodes immersed intransformer oil. It is important to detect failure in transformer oil early, asit helps to further assess the health of the transformer and prevent furtherdeterioration of the transformer. Determining the refractive index changes isan important method to monitor the deterioration of transformer oil. Oildeterioration is directly related to the refractive index of transformer oil.The density of the luminous flux used in the refractive index measurementchanges with the change in the refractive index of the oil. It shows that anold oil has a higher refractive index than a new oil. As the refractive indexof the oil increases, the breaking stress decreases. Therefore, the refractiveindex change will increase or decrease with the level of oil contamination,which indicates that the oil is new or old.In this study, therelationship between refractive index values ​​and diffraction voltage values​​of oil samples taken from different high power transformers at differenttimes was investigated. Previously, the refractive index values ​​of thesamples were measured with an IR280 refractometer. The refractive indices ofthe oils varied between 1.4699-1.4820. Then, voltage diffraction tests wereperformed on the samples taken with the OTS 60 AF device. The tests startedwith the process of heating the oil and reducing the moisture in it and thenthe voltage values ​​were increased starting from 0 V up to 60 KV. While thebreakdown voltage of 1.4699 oil was obtained as 60 KV, breakdown voltage of1.4820 was determined as 26.5 KV. It was seen from the results obtained thatoils with a low refractive index break at higher voltages and become conductive.The refractive indices of the samples whose refractive indices were measuredbefore the voltage diffraction test were also measured after the test. Sincethe high temperature created by each voltage diffraction test in the oil causesdeterioration in the chemical structure of the oil, a slight increase wasobserved in the refractive index values ​​after the test. This clearly revealsthe deterioration of the oil and the change in its chemical structure. Thehigher the value of the refractive index of the transformer oil, the lower thelight power losses in the oil sample.