Leakage Current Response Mechanism of Insulator String With Ambient Humidity on Days Without Rain

Wang, Jianguo; Xi, Yunping; Fang, Chunhua; Li, Cai; Wang, Jianping; Yang, Fan

doi:10.1109/access.2019.2910660

Cited by 18 publications

(32 citation statements)

References 13 publications

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“…Content may change prior to final publication. In addition, this case was in line with [10,12,15,17,18,26] because the rise in the local time occurred between 04:00 and 08:00. According to Pieterse et al [10], it occurred on the relatively low creepage distance of 615 mm, rather than the high creepage distance of 1175 mm.…”

Section: Figure 3sample Waveforms Of the Jpeg Picturesupporting

confidence: 79%

“…-0.90 to -1.00 (0.90 to 1.00) Very high negative (positive) correlation Generally, the data on one parameter were not inherently linear to the asymptotic patterns on the other parameters. Therefore, exponential models were employed to determine the regressions [12,[23][24], as shown in equation 4, where C and D are the constant and exponential constant of the regression, respectively.…”

Section: Size Of Correlation Interpretationmentioning

confidence: 99%

“…creepage distance were recorded at 1175 mm and 615 mm. Chrzan [11] reported a daily maximum amplitude of the insulator leakage currents for porcelain and silicone rubber, while Wang et al [12] investigated the daily LC magnitudes, humidity, temperature, and nonlinear (exponential) curve fitting of the leakage currents versus humidity on a glass insulator string. Vosloo and Holzhausen [13] investigated the leakage currents on EPDM, SIR, and glass insulators, and discovered that the glass insulator has the highest leakage at night, followed by EPDM and silicone rubber.…”

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The Evaluation of Daily Comparative Leakage Currents on Porcelain and Silicone Rubber Insulators Under Natural Environmental Conditions

2021

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In this research, the leakage current (LC) and applied voltage waveforms on samples of installed outdoor porcelain and silicone rubber (SIR) insulators were measured by using a storage digital oscilloscope concurrent with humidity, temperature, and illuminance measurements. Essentially, the measurements were conducted daily, every three hours, for thirty days, and the data were analyzed using exponential regressions, box plots, and correlation coefficients. The porcelain and SIR insulator leakage currents varied from 23.7 A to 28.8 A and 8.4 A to 10.35 A for median values, respectively, while for outlier excluded values, they varied from 20.3 A to 40.0 A and 5.1 A to 17.1 A, respectively. Both leakage currents slightly increased as the exposure duration of the insulator rose, while the ratio decreased very slightly. Additionally, the leakage currents decreased moderately and slightly as the temperature and illuminance increased, respectively. However, the parabolic leakage currents increased as the humidity rose, especially at high humidity. Therefore, the porcelain insulator was more susceptible than the daily SIR, while the SIR insulator was more highly influenced by aging of the exposure duration. The rainy condition contributed to the highest leakage currents on both insulators, whereas the drizzle condition contributed to the highest leakage current on the SIR insulator. The total harmonic distortion (THD) and phase angle of the porcelain insulator leakage currents experienced differences of 5.8% and 7.8 degrees in the minimum and maximum humidity, respectively, but both quantities were less for the SIR insulator. INDEX TERMS humidity, leakage current, porcelain, silicone rubber I. INTRODUCTION High voltage outdoor insulators have an important role in electrical power transmission and distribution systems, including operational reliability, safety, and efficiency [1]. However, their functions are mostly influenced by environmental conditions [2-3]. Common insulator materials include glass and porcelain, which are ceramic materials that have been used for hundreds of years. Moreover, composite and cast cycloaliphatic epoxy resin (epoxy resin, ER), as a polymeric category, has been used in the last few decades [3-4]. These insulators have sheds for reducing the electric field stress and tolerating the accumulation of pollution [5]. Currently, research conducted on insulator leakage currents based on daily time functions is limited. Vosloo et al. [6] illustrated the average peak leakage currents on some insulators, and Roman et al. [7] monitored the insitu dc leakage current magnitudes, namely, rain, humidity, and temperature, on composite and glass insulators. According to Castillo-Sierra et al. [8], the ceramic insulator leakage currents were measured using a clamp meter, as were the temperature and humidity, followed by a regression analysis. Further research by Vosloo and Holtzhausen [9] showed that the peak leakage current of porcelain insulators, including precipitation, relative humidity (RH), ul...

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Section: Figure 3sample Waveforms Of the Jpeg Picturesupporting

confidence: 79%

Section: Size Of Correlation Interpretationmentioning

confidence: 99%

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confidence: 99%

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The Evaluation of Daily Comparative Leakage Currents on Porcelain and Silicone Rubber Insulators Under Natural Environmental Conditions

2021

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“…Concurrently, the online measurements of LCVS, from the insulator, are required to be fed to the MNN which is trained to recognize the contamination type using LCVs. However, online translation of surface leakage current measurements of insulators is still open to research [39,40]. Therefore, in the present work, pre-measured LCVs (experimental measurements, 18 × 5 = 90) were used and encoded with the MNN.…”

Section: A Proposed Fcn Architecturementioning

confidence: 99%

Multi-Modal Data Fusion Using Deep Neural Network for Condition Monitoring of High Voltage Insulator

et al. 2020

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A novel Fusion Convolutional Network (FCN) is proposed in this research for potential realtime monitoring of insulators using unmanned aerial vehicle (UAV) edge devices. Precise airborne imaging of outdoor objects, such as high voltage insulators, suffers from varied object resolution, cluttered backgrounds, unclear or contaminated surfaces, and illumination conditions. Accurate information about the insulator surface condition is essential and is of a high priority since insulator breakdown is a leading cause of electrical failure. A multi-modal information fusion (MMIF) system is developed during this research to analyze and classify possible contaminations present on the electrical insulators. A novel system, referred to as FCN, consists of a Convolutional Neural Network (CNN) and a binary Multilayer Neural Network (MNN) sub-classifier. While constructing the MMIF dataset for training and testing the novel FCN, the image classification output of the CNN is combined with the leakage current values (LCV) obtained as the classification output of MNN. Each sample of the MMIF dataset is, therefore, represented as a series of fusions. Later, sub-classifiers, of the FCN, are trained to identify the contamination types in the fusion series by implementing a voting system of sub-classifiers which is trained to identify a given class. As a result of the implementation of the proposed FCN, the classification accuracy increased by 8.4%, i.e., from 92% to 99.76%. To compare and benchmark the performance of proposed FCN, conventional classification algorithms are also implemented on the fusion of features that are extracted employing the wavelet transform and PCA methods. State-of-the-art CNN architectures are also discussed on account of their time consumption and memory usage. The conceptualization of a potential hardware implementation of the proposed FCN, on emerging edge devices, is also provided for completeness of the discussion. Pertinent outcomes of this research can be further extended to other potential applications of airborne imaging. INDEX TERMS Convolutional Neural Network, multi-modal information fusion, electrical insulators, unmanned aerial vehicle.

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“…A reasonably high correlation is observed (coefficient of determination ≈ 0.6), though the correlation drops in highly polluted insulators. In [13], the leakage current in insulator strings is correlated against temperature and ambient humidity in a 110 kV system. It is observed that the leakage current exhibits a positive correlation with RH (coefficient of determination > 0.8) and a negative correlation with temperature.…”

Section: Previous Workmentioning

confidence: 99%

Non-Contact Measurement and Analysis of Trapped Charge Decay Rates for Cable Line Switching Transients

et al. 2020

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During reclosure of 275 kV cable circuits used for voltage control, excessive overvoltages were observed on the network. Such events cause onerous and costly failures. Transient simulations have shown that the normal voltage on its own cannot generate such excessive switching overvoltages. Initial investigations by the network operator pointed towards trapped charge on the unearthed as the cause of the failures. Measurement of these trapped charge voltages and their slow decay without interfering with the charge has, to the author’s knowledge, not been done before in an operational substation. This work introduces a technique to measure trapped charge at a 275 kV substation using the Electrostatic Field Mill. Since the electric field is a proxy measurement of surface voltage, field mills can also be used to measure voltage. In this paper, an on-site substation measurement setup using an electrostatic field mill has been developed for the non-contact measurement of trapped charge voltage on a 275 kV underground cable circuit following switching operations at a National Grid substation. Results of field measurements within the substation and laboratory experimentation are discussed. It is demonstrated that with adequate calibration, achieved by using the known pre-switching power frequency steady state voltage, the slowly decaying DC voltage caused by the cable trapped charge can be measured using this non-contact technique. The correlation between the instantaneous time constant and the relative humidity is also analysed.

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Leakage Current Response Mechanism of Insulator String With Ambient Humidity on Days Without Rain

Cited by 18 publications

References 13 publications

The Evaluation of Daily Comparative Leakage Currents on Porcelain and Silicone Rubber Insulators Under Natural Environmental Conditions

The Evaluation of Daily Comparative Leakage Currents on Porcelain and Silicone Rubber Insulators Under Natural Environmental Conditions

Multi-Modal Data Fusion Using Deep Neural Network for Condition Monitoring of High Voltage Insulator

Non-Contact Measurement and Analysis of Trapped Charge Decay Rates for Cable Line Switching Transients

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