ASSESSING THE RELIABILITY OF TRANSFORMER TOP OIL TEMPERATURE MODEL

2012 ◽  
Vol 19 (05) ◽  
pp. 1250024 ◽  
Author(s):  
M. SRINIVASAN ◽  
A. KRISHNAN
Keyword(s):  
Ambient Temperature ◽  
Power Transformer ◽  
Hot Spot ◽  
Real Data ◽  
Measured Data ◽  
Heat Radiation ◽  
Model Parameters ◽  
Physically Based Model ◽  
Physically Based ◽  
Spot Temperature

The hot spot temperature (HST) plays a most important role in the insulation life of the transformer. Ambient temperature and environmental variable factors involved in the top oil temperature (TOT) computations in all transformer thermal models affects insulation lifetime either directly or indirectly. The importance of the ambient temperature in transformer's insulation life, a new semi-physically-based model for the estimation of TOT in transformers has been proposed in this paper. The winding hot-spot temperature can be calculated as function of the TOT that can be estimated by using the ambient temperature, wind velocity and solar heat radiation effect and transformer loading measured data. The estimated TOT is compared with measured data of a distribution transformer in operation. The proposed model has been validated using real data gathered from a 100 MVA power transformer. For a semi-physically-based model to be acceptable, it must have the qualities of: adequacy, accuracy and consistency. We assess model adequacy using the scale: prediction R2, and plot of residuals against fitted values. To assess model consistency, we use: variance inflation factor (VIF) (which measure multicollinearity), condition number. To assess model accuracy we use mean square error, maximum and minimum error values of semi-physically-based model parameters to the existing model parameters.

Economic, Safe and Optimized Strategy of Operation of Transformer in Parallel Considering the Hot-Spot Temperature

2013 ◽  
Vol 448-453 ◽  
pp. 2316-2325
Author(s):  
Zhi Min He ◽  
Ya Dong Liu ◽  
Wen Shen ◽  
Xu Ri Sun ◽  
Hong Jie Wang ◽  
...  
Keyword(s):  
Switching Time ◽  
Power Transformer ◽  
Hot Spot ◽  
Operation Mode ◽  
Load Curve ◽  
Economic Operation ◽  
Environment Temperature ◽  
Typical Time ◽  
Daily Load ◽  
Spot Temperature

In order to improve the economy of operation of transformer, this study presents a strategy to ensure the safety of power transformer for the situation of overload operation of parallel transformer. According to the variation of actual transformer operation, the authors divide the daily load curve into two typical time periods. In the high load operation period, except the constraint of minimum power loss for the economic operation, the factor for hot-spot temperature rise of the transformer should also be considered, so that an economic operation mode and parallel switching time could be obtained. This strategy estimates the hot spot temperature by the finite difference method, and obtains the optimal switching time through binary searching, according to the environment temperature and load curve. The analysis of the example of the operation of two sets of three winding transformers in parallel with different capacity shows that the method of optimization of the operation could reduce the loss. In the meantime, it could ensure the operation safety of the transformer, and prolong the service life of transformer.

scholarly journals Numerical analysis of the hot-spot temperature of a power transformer with alternative dielectric liquids

2017 ◽  
Vol 24 (5) ◽  
pp. 3226-3235 ◽  
Author(s):  
A. Santisteban ◽  
F. Delgado ◽  
A. Ortiz ◽  
I. Fernandez ◽  
C.J. Renedo ◽  
...  
Keyword(s):  
Numerical Analysis ◽  
Power Transformer ◽  
Hot Spot ◽  
Dielectric Liquids ◽  
Spot Temperature

scholarly journals THE FRAMEWORK ON MULTI-SCALE LANDSLIDE HAZARD EVALUATION IN CHINA

2016 ◽  
Vol XLI-B8 ◽  
pp. 105-107 ◽  
Author(s):  
W. Y. Li ◽  
C. Liu ◽  
J. Gao
Keyword(s):  
Hot Spot ◽  
Regional Scale ◽  
Landslide Hazard ◽  
Physical Models ◽  
Slope Instability ◽  
Hazard Evaluation ◽  
Landslide Risk ◽  
Physically Based Model ◽  
Multi Scale ◽  
Physically Based

Nowadays, Landslide has been one of the most frequent and seriously widespread natural hazards all over the world. How landslides can be monitored and predicted is an urgent research topic of the international landslide research community. Particularly, there is a lack of high quality and updated landslide risk maps and guidelines that can be employed to better mitigate and prevent landslide disasters in many emerging regions, including China. This paper considers national and regional scale, and introduces the framework on combining the empirical and physical models for landslide evaluation. Firstly, landslide susceptibility in national scale is mapped based on empirical model, and indicates the hot-spot areas. Secondly, the physically based model can indicate the process of slope instability in the hot-spot areas. The result proves that the framework is a systematic method on landslide hazard monitoring and early warning.

scholarly journals Development of an Improved Model for Assessment of Hot Spot Temperature of Current Transformers

2018 ◽  
Vol 6 (2) ◽  
pp. 12-16
Author(s):  
Ganiyu Adedayo Ajenikoko ◽  
Emmanuel Babatunde Badmus
Keyword(s):  
Ambient Temperature ◽  
Hot Spot ◽  
Load Cycle ◽  
Current Transformer ◽  
Rate Of Change ◽  
Temperature Model ◽  
Current Transformers ◽  
Temperature State ◽  
Improved Model ◽  
Spot Temperature

Current transformers form important components that make up a large portion of capital investments. Failure of a current transformer results in an adverse effect in the operation of transmission networks which causes an increase in the power system operation cost and inability to deliver electricity with absolute reliability. The age of a transformer is the life of its insulation, majorly, paper insulation. Transformer aging can be evaluated using the hot spot temperature which has the effect of reducing the insulation life of transformers. Previous researchers have developed models for assessment of top-oil temperature of current transformers. Such models have the limitation that they do not accurately account for the variation effect in ambient temperature and hence not applicable for an on-line monitoring system. This research paper develops an improved model for assessment of hot spot temperature from the IEEE top-oil rise temperature model by considering the ambient temperature at the first-order characterization using appropriate mathematical notations. The ambient temperature, top oil rise over temperature and winding hot spot rise over temperature were used as input parameters for the development of the improved hot spot temperature model by considering the final temperature state since the time-rate-of change in top-oil temperature is driven by the difference between the exits top-oil temperature for ambient temperature variation. The improved model was then implemented in MATLAB to compute the hot spot temperature for 24-hour load cycle. The result of the improved model shows that the least and highest value of the hot spot temperature are 630C and 105.40C respectively indicating a retardation in the aging process of the transformers. The improved model helps to minimize the risk of failure and to extend the life span of transformers thereby controlling the hot spot temperature rise and top oil temperature.

A complementary modelling approach to manage uncertainty of computationally expensive models

2007 ◽  
Vol 56 (8) ◽  
pp. 1-9 ◽  
Author(s):  
Z. Vojinovic
Keyword(s):  
Support Vector ◽  
Model Parameters ◽  
Machine Model ◽  
Systematic Analysis ◽  
Physically Based Model ◽  
Physically Based ◽  
Computationally Expensive ◽  
Estimation Of Model Parameters ◽  
Insight Into ◽  
Modelling Approach

The fact that the models applied in the ‘water domain’ are far from reality can be attributed to many reasons. In this context, a systematic analysis of uncertainties reflected by the model error can provide insight into the level of confidence in the model results and how to approach estimation of optimal model parameters. This paper discusses the four commonly used approaches for estimation of model parameters and suggests that an alternative complementary modelling approach should be considered in cases where the traditional model calibration gives limited results and particularly in cases where the computationally expensive models are concerned. It treats uncertainty as modelling the total discrepancy between the model and physical process. The proposed approach combines the results from a physically-based model and Support Vector Machine model into the final solution.

Sign in / Sign up

Export Citation Format

Share Document