Health Analysis of Transformer Winding Insulation Through Thermal Monitoring and Fast Fourier Transform (FFT) Power Spectrum

Abstract

This paper presents a health analysis technique for transformer winding insulation through thermal monitoring and Fast Fourier Transform (FFT) power spectrum. A novel thermal model for the Kraft paper insulation of transformer is proposed by using the transformer's top-oil and winding hot-spot temperature models. The relationship between the temperature rise of oil inside the transformer tank and the winding insulation degradation are considered by utilizing the data-sets and daily load cycles of a 10/13 MVA, 132/11 kV, 50 Hz, ONAF grid power transformer. The model based on IEEE Guide for loading mineral-oil-immersed transformers is developed in Simulink. The hotspot temperature rise from the thermal model is used as a reference to analyze the winding insulation degradation in the form of high frequency partial discharges (PDs) upon the output parameters of the transformer. Using data analysis techniques, a correlation is presented between the load cycles and the hot-spot temperature through which the health status of the transformer winding insulation is estimated. Moreover, the high frequency transients were detected using the Fast Fourier Transform (FFT) spectrum analyzer tool in MATLAB. The preliminary study shows that high frequency PDs are detected for the overheated and deteriorated state of the winding insulation. The results show that the proposed technique is feasible for the health analysis of power transformers and successfully predicted the deterioration of the transformer winding insulation.

Large-Power Transformers: Time Now for Addressing Their Monitoring and Failure Investigation Techniques

“…Thus, it is possible to estimate the oil temperature at the top of the transformer and in the hotspot with all the data necessary for applying the thermal model. (8) in Table 11. Thus, it is possible to estimate the oil temperature at the top of the transformer and in the hotspot with all the data necessary for applying the thermal model.…”

“…One must recognize several review studies in the literature on monitoring, fault detection, and diagnosis of power transformers. However, those reviews are general approaches in terms of power transformers as recent examples of reviews published in [7][8][9][10][11], reviews focusing on the application of a specific class of techniques again for general power transformers as in [12][13][14], and reviews centered in applying different technologies like fiber optics in [15], thermal cameras in [16], vibration sensors in [16,17], but all within general power transformers' perspective.…”

Prognostication of Failures Using Signal-to-Noise Ratio to Determine Partial Discharges Activities in Power Transformers

“…However, this traditional method depends on the sensitivity of the radio receiver and the directivity of the antenna and is less accurate, and does not provide the magnitude of the PD pulse [22]. Besides, with traditional method the exact source and location of PD cannot be identified [23,24]. Partial discharges, also accompanied by thermal effects inside the insulation are mainly responsible for its gradual degradation and therefore are the key contributor towards insulation deterioration [25].…”

Polysilsesquioxane-modified Cellulose Insulating Paper with Excellent Mechanical Properties, Electrical Properties and Aging Resistance

“…In order to ensure that the constructed model could re ect the physical and chemical properties of real materials, and in view of the time cost of molecular simulation and the di culty of model optimization, the cellulose molecular chain with polymerization degree of 10 was built. The actual value of transformer insulating paper, 1.5 g/cm 3 , was taken as the molecular density of the model. The temperature was set as 298 K, the charge distribution method was Force eld assigned, and the force eld was COMPASS force eld.…”

“…Its normal and e cient operation is an important guarantee for power transmission (Abbasi 2022;Liu et al 2020;Carrascal et al 2018). Winding is a key component in power transformer, whereas paper oil insulation is an important support and insulation component of transformer winding (Dawood et al 2022; Aslam et al 2021). Therefore, improving the performance of cellulose insulation paper to extend the service life of transformers has important strategic signi cance for the power system (Thiviyanathan et al 2022; Dos Santos et al 2010).…”