Long-term Online Partial Discharge Trend Monitoring for Cast Resin Transformers in Switchboard

2020 ◽  
Author(s):  
Yasutomo Kakimoto ◽  
Tatsuki Jogo ◽  
Masahiro Kozako ◽  
Masayuki Hikita ◽  
Masaharu Sato ◽  
...  
Keyword(s):  
Partial Discharge ◽  
Trend Monitoring

scholarly journals Study on the Correlation between Partial Discharge Energy and SF6 Decomposition Gas Generation

Energies ◽  
2020 ◽  
Vol 13 (18) ◽  
pp. 4655
Author(s):  
Yong Sung Cho ◽  
Tae Yoon Hong ◽  
Young Woo Youn ◽  
Jong Ho Sun ◽  
Se-Hee Lee
Keyword(s):  
Partial Discharge ◽  
Surface Discharge ◽  
Discharge Energy ◽  
The Finite Element Method ◽  
Gas Generation ◽  
Energy Effect ◽  
Sf6 Decomposition ◽  
Maintenance Process ◽  
The Relationship

In this paper, the amount of SF6 decomposition gases due to the partial discharge (PD) was studied in the SF6 gas-insulated transformer. The long-term PD degradation experiment was performed while controlling the discharge magnitude using the surface discharge, and the gas generation amount was measured by using gas chromatography for SO2F2, SOF2, SO2, CO, and CF4. In addition, to investigate the relationship between the partial discharge energy and the decomposed gas generation amount, partial discharge energy was calculated by a data processing program and converted to the unit of joule per mole. With the finite element method (FEM), the electric field distribution and SF6 gas decomposition mechanism were explained for the partial discharge energy effect on the gas generation. This study helps understand the relationship between the partial discharge energy and the decomposed gas generation ratio with the experimental results and can be used for the diagnosis of PD and maintenance process for the gas-insulated transformers.

Long-Term Sequential Characteristics of Negative Partial Discharge in Pressurized SF6 Gas

2001 ◽  
pp. 205-210 ◽  
Author(s):  
T. Takahashi ◽  
M. F. Fréchette ◽  
R. Y. Larocque ◽  
C. Hudon ◽  
T. Umemura ◽  
...  
Keyword(s):  
Partial Discharge

scholarly journals Research on Transformer Partial Discharge UHF Pattern Recognition Based on Cnn-lstm

Energies ◽  
2019 ◽  
Vol 13 (1) ◽  
pp. 61 ◽  
Author(s):  
Xiu Zhou ◽  
Xutao Wu ◽  
Pei Ding ◽  
Xiuguang Li ◽  
Ninghui He ◽  
...  
Keyword(s):  
Pattern Recognition ◽  
Spatial Information ◽  
Short Term Memory ◽  
Partial Discharge ◽  
Surface Discharge ◽  
Recognition Ability ◽  
Void Defects ◽  
Memory Network ◽  
Local Spatial Information

In view of the fact that the statistical feature quantity of traditional partial discharge (PD) pattern recognition relies on expert experience and lacks certain generalization, this paper develops PD pattern recognition based on the convolutional neural network (cnn) and long-term short-term memory network (lstm). Firstly, we constructed the cnn-lstm PD pattern recognition model, which combines the advantages of cnn in mining local spatial information of the PD spectrum and the advantages of lstm in mining the PD spectrum time series feature information. Then, the transformer PD UHF (Ultra High Frequency) experiment was carried out. The performance of the constructed cnn-lstm pattern recognition network was tested by using different types of typical PD spectrums. Experimental results show that: (1) for the floating potential defects, the recognition rates of cnn-lstm and cnn are both 100%; (2) cnn-lstm has better recognition ability than cnn for metal protrusion defects, oil paper void defects, and surface discharge defects; and (3) cnn-lstm has better overall recognition accuracy than cnn and lstm.

scholarly journals Long-Term Asthma Trend Monitoring in New York City: A Mixed Model Approach

2013 ◽  
Vol 5 (1) ◽  
Author(s):  
Stephen E. Schachterle ◽  
Robert W. Mathes ◽  
Marc Paladini ◽  
Don Weiss
Keyword(s):  
New York ◽  
New York City ◽  
York City ◽  
Mixed Model ◽  
Mixed Model Approach ◽  
Trend Monitoring ◽  
Model Approach

scholarly journals Pre-Breakdown and Breakdown Behavior of Synthetic and Natural Ester Liquids under AC Stress

Energies ◽  
2021 ◽  
Vol 15 (1) ◽  
pp. 167
Author(s):  
Beki Sékongo ◽  
Stephan Brettschneider ◽  
U. Mohan Rao ◽  
Issouf Fofana ◽  
Marouane Jabbari ◽  
...  
Keyword(s):  
Electric Field ◽  
Thermal Aging ◽  
Power Transformer ◽  
Partial Discharge ◽  
Service Condition ◽  
Mineral Oil ◽  
Radius Of Curvature ◽  
Long Term Behavior ◽  
Inception Voltage

In the last decades, a large focus is being placed on the sustainability and safety of the power transformer spectrum. Ester liquids, which have interesting properties such as high fire point and biodegradability, are gaining needed attraction. Since in-service condition, thermal aging deteriorates the physicochemical and electrical properties of liquid dielectrics, it is important to study their long-term behavior. In this contribution, the pre-breakdown and breakdown behavior of ester fluids (synthetic and natural) under AC stress are investigated. Important characteristics, such as partial discharge pre-inception voltage, partial discharge inception voltage, breakdown voltage, average streamer velocity, and inception electric field, were assessed. The influence of the radius of curvature (of high voltage needle electrode) as well as the thermal degradation of typical ester liquids are also discussed. Mineral oil was also included in the tests loop as a benchmark for comparative purposes. It is found that the pre-inception voltage of ester liquids was, in most cases, higher than that of mineral oil. For a given radius of curvature, the streamer inception and breakdown voltages decreased with thermal aging. During the streamer initiation, the electric field at the electrode tip decreased with the increase in the radius of curvature. The velocity of the streamers seems to increase with the decrease in the radius of curvature. The period of vulnerability, the so-called “delay time”, seems to be independent of the aging or the radius of curvature for a given condition of the liquid.

scholarly journals Development Processes of Surface Trucking and Partial Discharge of Pressboards Immersed in Mineral Oil: Effect of Tip Curvatures

Energies ◽  
2019 ◽  
Vol 12 (3) ◽  
pp. 554 ◽  
Author(s):  
Bo Gao ◽  
Rui Yu ◽  
Guangcai Hu ◽  
Cheng Liu ◽  
Xin Zhuang ◽  
...  
Keyword(s):  
High Speed ◽  
Weak Link ◽  
Partial Discharge ◽  
Mineral Oil ◽  
Tangential Component ◽  
Surface Tracking ◽  
Damage Degree ◽  
Development Processes ◽  
Paper Insulation

The pressboard surface is the electric weak link of the oil-paper insulation in transformers, and long-term partial discharge (PD) erosion is the dominant cause of degradation in pressboard. To explore the development processes of surface tracking under the effect of tip curvature, the typical needle-plate model was selected to initiate an electric field with a high tangential component on pressboard surface under needle tip curvature of 4~42 μm. With the help of a high-speed camera and a PD detecting system, the development processes of surface tracking and PD were recorded under a sustained AC voltage. A profound difference between surface tracking under different curvatures was discussed. Pressboard surfaces after tests were observed under a scanning electron microscope (SEM), and the damage degree of cellulose fibers was dependent on the tip curvature.

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