Leakage Current Pulses Research Articles

Categorizing 15 kV High-Voltage HDPE Insulator’s Leakage Current Surges Based on Convolution Neural Network Gated Recurrent Unit

The leakage currents are appropriate for determining the contamination level of insulators in the power distribution system, which are efficiently cleaned or replaced during the maintenance schedule. In this research, the hybrid convolution neural network and gated recurrent unit model (CNN-GRU) are developed to categorize the leakage current pulse of the 15 kV HDPE insulator in the transmission towers in Taiwan. Many weather parameters are accumulated in the online monitoring system, which is installed in different transmission towers in coastal areas that suffer from heavy pollution. The Pearson correlation matrix is computed for selecting the high correlative features with the leakage current. Hyperparameter optimization is employed to decide the enhancing framework of the CNN-GRU methodology. The performance of the CNN-GRU is completely analyzed with other deep learning algorithms, which comprise the GRU, bidirectional GRU, LSTM, and bidirectional LSTM. The developed CNN-GRU acquired the most remarkable improvements of 79.48% CRE, 83.54% validating CRE, 14.14% CP, 20.89% validating CP, 66.24% MAE, 63.59% validating MAE, 73.24% MSE, and 71.59% validating MSE benchmarks compared with other methodologies. Therefore, the hybrid CNN-GRU methodology provides comprehensive information about the contamination degrees of insulator surfaces derived from the property of leakage currents.

Monitoring of Dry Bands and Discharge Activities at the Surface of Textured Insulators with AC Clean Fog Test Conditions

The aim of this study is the presentation of the results of an in-lab comparative study of electrical and thermal monitoring of artificially polluted, HTV-textured silicone rubber insulators, with different pollution levels. This work is a preliminary study of an in-situ monitoring of 400 kV SiR textured in a polluted environment. The results showed that the rms leakage current magnitude and pulses, and the average dissipated power depended on the pollution levels and the dry-bands formation. The discharge activity and their nature are governed by the pollution level and the voltage. A differentiation and a quantification between dry-band discharge onset and dry-band arc inception is highlighted.

실리콘/표면개질된 Nano SiC 충진함량별 복합재의 (+)HVDC IPT 트래킹 및 침식저항에 관한 연구

SiC(Silicon Carbide) is generally used for abrasives, grinding stones, ceramic coating paints, heat sinks for system LSIs, and next-generation semiconductors. However, in the power part, it is used by attaching to the end winding of the electric machine to reduce high voltage stress and prevent surface spark discharge. As for the measurement sample, a tracking sample was prepared by filling the surface-modified Nano SiC in SiR with a filling content of 1,3,5,7wt%. The experimental conditions for tracking and erosion were applied voltage (+)HVDC_4.5kV and the rate of contaminant was 0.25ml/min. Tracking and erosion tests can cause electrical erosion on the surface. The thermal conductivity of an insulator is related to its resistance to tracking and erosion. For that reason, in this study, we would like to confirm whether the resistance to tracking and erosion of SiR is improved by increasing the filling content of nano SiC in SiR. As the result of the experiment, as the SiC filling content increased, the thermal conductivity increased, and on the contrary, the tracking and erosion test results showed that the amount of erosion decreased. In addition, the leakage current pulse size also showed a result of weakening the dry versus arc current pulse.

Space charge distribution and leakage current pulses for contaminated glass insulator strings in power transmission lines

This study reports an investigation on space charge distribution and leakage current (LC) pulses of four units of glass insulators recently removed from service. Simulation works were conducted using finite element software and validated by laboratory experiments. The simulation and experimental results were found to be in good agreement when studying the space charge distribution pattern along the glass insulator string. It is evident that the LC waveform can be used to characterise the types of partial discharge according to their occurrence with respect to the AC supply. Thus, the proposed method is viable and reliable to be applied in an online measurement system.

The Design of Insulator Leakage Current Monitoring Device Based on MSP430 Microcontroller

This article describes a transmission line insulator leakage current monitoring device, the device is based on the MSP430 ultra low power mixed signal controller design, both the transmission line insulator leakage current rms leakage current pulse, the leakage current pulse frequency and ambient humidity characteristic quantities to be monitored, with low power consumption, high reliability.

Tracking and erosion of HTV silicone rubber and suppression mechanism of ATH

Tracking and erosion of high temperature vulcanizing (HTV)-silicone rubber (SIR) and the suppression mechanism of alumina trihydrate (ATH) filler were investigated in the present study. The tracking and erosion resistance of HTV-SIR filled with 0 to 60%wt ATH was evaluated by employing an IEC 587 inclined plane (IP) tracking and erosion test, during which leakage current pulses on HTV-SIR were counted. Surface temperature distributions and the occurrences of thermal spots >400/spl deg/C also were observed by means of an infrared thermovision study. We employed thermogravimetry (TG)-differential thermal analysis (DTA)-mass spectrometer (MS) to observe the thermal degradation of unfilled and filled HTV-SIR in both air and argon. The test results indicate that 40%wt is a critical ATH level and whether tracking and erosion is allowed in the IP tracking and erosion test. Highly filling ATH (>40%wt) reduces the number of low unit silicone oligomer precursors which promote dry-band arcing as well as the presence of residual carbon which leads to carbonization. Chemical modifications of water vapor liberated from heated ATH to methyl groups, which occurs at the thermal decomposition temperature of silicone rubber, were found to result in the above process. The protection mechanisms of ATH for the tracking and erosion of HTV-SIR are formulated herein.

Electrical salt-fog performance of XLPE insulation with different levels of CaCO/sub 3/

This paper presents a study of the electrical performance of crosslinked polyethylene (XLPE) in salt fog conditions. Specimens of XLPE having 0, 15 and 25% calcium carbonate (CaCO/sub 3/) filler, a fixed concentration of 2% carbon black and an additional ultraviolet stabilizer were used. The leakage current and the current pulse counts were monitored as a function of time of exposure to combined electrical stress and salt-fog. Both leakage current and current pulse count were found to increase with increasing test time and with increasing filler concentration. The time to failure of the specimens as a function of the filler concentration was found to increase with increasing filler level. The contact angle decreased, and the surface roughness increased with increasing test time in energized salt fog. A SEM study showed that the surface roughness increased with increasing filler levels, giving an independent confirmation of the results obtained from the surface roughness tester. The EDAX study showed that the intensity count of X-ray of calcium on the surface increased after salt-fog test, indicating that CaCO/sub 3/ was not removed from the surface. Both the SEM and EDAX studies confirmed that the number of CaCO/sub 3/ particles on the surface increased with increasing filler level. It is suggested this was responsible for the observed larger roughness of the surface, higher resistance to arcing erosion and longer lifetime of XLPE polymer with increasing level of CaCO/sub 3/ filler.

Practical PCA-DA system for measurement of leakage current pulses on polymer insulators under wet contaminated conditions

A practical PC-DA system for automatically measuring and recording leakage currents and discharge pulses over long periods is described. A standard PC with an industry standard analog-to-digital converter plug-in board is used in the system. The software is designed to sample eight channels (insulators) up to 1000 Hz each. The test results from studies of insulators in a fog-chamber environment and in outdoor polluted conditions are reported. The performance of the system has been satisfactory.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Influence of AC Source Parameters on Flashover Characteristics of Polluted Insulators

The paper comprises a systematic experimental investigation into the influence of AC test source parameters on the leakage current pulses, voltage fluctuations and flashover voltages of polluted insulators. The test techniques include both salt-and clean-fog methods, while the test insulators comprise long-rod and cap and pin strings of different lengths as well as support columns.

Enhanced leakage-current pulse-induced changes in impatt oscillators

Two types of stables changes in c.w. X-band impatt oscillators have been observed after exposure to pulses of enhanced leakage current. The first change is indicated by a change in r.f. power and frequency while maintaining a `clean? r.f. spectrum, and is attributed to parasitic circuit-induced instabilities (with changes in oscillator characteristics thought to be influenced by changes in harmonic phasing). The second change is indicated by a modulated r.f. spectrum and oscillations in bias voltage after irradiation, and is clearly attributed to bias-circuit oscillations. These conclusions are supported by experimental results with Si and GaAs diodes in a resonant cap waveguide oscillator circuit. Enhanced leakage-current pulses up to 5 mA in amplitude were obtained using 10 MeV electron pulses from a linear accelerator. The r.f. impedance was adjusted by varying the sliding short-circuit position, while the bias-circuit impedance was varied independently by inserting various length cables between an RC bias network and the diode.