Transformer Bushing Thermal Model for Calculation of Hot-Spot Temperature Considering Oil Flow Dynamics

Akbari, Milad; Rezaei-Zare, Afshin

doi:10.1109/tpwrd.2020.3014064

Cited by 27 publications

(8 citation statements)

References 19 publications

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“…Circuits ( 2) and (3) were connected to the heating circuit simultaneously. The bushing was supplied with rated current of 630 A, and the oil tank temperature was controlled at 90 • C (according to IEEE standards, the temperature at the top of the transformer generally does not exceed the ambient temperature +60 K) [23]. During the test, a temperature and a barometer were set in the room to consider the environmental influence, and the sampling interval was 15 min.…”

Section: Control Boltmentioning

confidence: 99%

Oil Pressure Monitoring for Sealing Failure Detection and Diagnosis of Power Transformer Bushing

Chen

et al. 2021

Energies

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Power transformer bushings withstand great electrical and mechanical stress during high voltage and high current working conditions. Sealing failure poses a great threat to the long-term and reliable operation of the bushing and power transformer; however, the criterion to evaluate the sealing status of a bushing caused by mechanical problems is still lacking. In this paper, a transformer bushing model is established to gain theoretical insight into the relationship between temperature and pressure of a compact multilayer bushing. To evaluate the bushing mechanical status, different sealing conditions are tested based on the temperature and pressure monitoring within the physical 110 kV bushing. The results show that mechanical sealing failure can be diagnosed when the fluctuation of the oil pressure value exceeds the theoretical curve in steady state by 3 kPa. With different reliability coefficients, gas leakage and oil leakage are available to be further determined. The primary and auxiliary criteria based on oil pressure and its gradient are proposed to evaluate comprehensively the actual sealing condition of the bushing, and a wireless oil pressure module is developed at the bottom valve, which is quite beneficial to field online application. It is promising to extend the online mechanical monitoring and diagnosis to oil-immersed power equipment.

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Section: Control Boltmentioning

confidence: 99%

Oil Pressure Monitoring for Sealing Failure Detection and Diagnosis of Power Transformer Bushing

Chen

et al. 2021

Energies

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“…In order to anticipate the thermal behavior of an oil-immersed power transformer for given load conditions, dynamic thermal models must be somehow considered. This is the case of [1], where a hybrid numerical-analytical technique is proposed, or the bushing thermal model presented in [2] to calculate the hot-spot temperature.…”

Section: Introductionmentioning

confidence: 99%

Parameter Estimation for Hot-spot Thermal Model of Power Transformers Using Unscented Kalman Filters

Cagigal

Rosendo-Macias²,

Gomez-Exposito³

2023

Journal of Modern Power Systems and Clean Energy

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This paper presents a parameter estimation technique for the hot-spot thermal model of power transformers. The proposed technique is based on the unscented formulation of the Kalman filter, jointly considering the state variables and parameters of the dynamic thermal model. A two-stage estimation technique that takes advantage of different loading conditions is developed, in order to increase the number of parameters which can be identified. Simulation results are presented, which show that the observable parameters are estimated with an error of less than 3%. The parameter estimation procedure is mainly intended for factory testing, allowing the manufacturer to enhance the thermal model of power transformers and, therefore, its customers to increase the lifetime of these assets. The proposed technique could be additionally considered in field applications if the necessary temperature measurements are available.

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“…An accurate estimation of the winding HST is required to assess the health of power transformer. It is one of the critical limiting factors for transformer loading, thus it increases the significance of determining the HST at every moment of transformer operation with real load condition and ambient temperature [5]. There are two possible methods for determining the HST.…”

Section: Introductionmentioning

confidence: 99%

Dynamic Thermal Model for Power Transformers

et al. 2021

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The prediction and determination of thermal response for the metallic parts is a very crucial step in the design of power transformers. This paper presents a comparative analysis of different thermal models for predicting the hotspot temperature and top oil temperature of power transformers. Also, a new thermal model is proposed for the monitoring of transformer operation which is capable of identifying the hotspot temperature and the top oil temperature by taking into account the ambient temperature and the load variation with respect to real time. The model is experimentally validated and compared with the actual field data. It is found that results obtained from the proposed model and the actual field data are in good agreement.

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Transformer Bushing Thermal Model for Calculation of Hot-Spot Temperature Considering Oil Flow Dynamics

Cited by 27 publications

References 19 publications

Oil Pressure Monitoring for Sealing Failure Detection and Diagnosis of Power Transformer Bushing

Oil Pressure Monitoring for Sealing Failure Detection and Diagnosis of Power Transformer Bushing

Parameter Estimation for Hot-spot Thermal Model of Power Transformers Using Unscented Kalman Filters

Dynamic Thermal Model for Power Transformers

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