scholarly journals Extracting the Resistive Current Component from a Surge Arrester’s Leakage Current without Voltage Reference

Sensors ◽  
2021 ◽  
Vol 21 (4) ◽  
pp. 1257
Author(s):  
Vid Vončina ◽  
Jože Pihler ◽  
Miro Milanovič
Keyword(s):  
Leakage Current ◽  
Data Transfer ◽  
Electronic Device ◽  
Theoretical Background ◽  
Voltage Reference ◽  
Current Component ◽  
Surge Arresters ◽  
Transfer Unit ◽  
Control Centre ◽  
Resistive Component

This article presents the development of the theoretical background and the design of an electronic device for monitoring the condition of a gapless Metal Oxide Surge Arrester (MOSA). The device is intended to be used online. Because of the inaccessibility and possible remote location of most surge arresters, it is equipped with a communication system, allowing for the device to convey the measurement of the surge arrester characteristics under any conditions. It is possible to determine the condition of the MOSA by gathering measurements of the surge arrester’s resistive component of leakage current. The leakage current information is sent via data transfer unit to a server and, after interpretation, will be forwarded to the authorised personnel through the surge arrester control centre.

scholarly journals Circuit-based method for extracting the resistive leakage current of metal oxide surge arrester

2020 ◽  
Vol 9 (6) ◽  
pp. 2213-2221 ◽  
Author(s):  
Amir Hesam Khavari ◽  
Abdullah Munir ◽  
Zulkurnain Abdul- Malek
Keyword(s):  
Metal Oxide ◽  
Leakage Current ◽  
Extraction Method ◽  
Maximum Error ◽  
Condition Assessment ◽  
Experimental Results ◽  
Equivalent Model ◽  
Surge Arresters ◽  
Total Leakage ◽  
Resistive Component

Resistive leakage current based condition assessment of metal oxide surge arrester (MOSA) is one of the most extensively employed technique to monitor its degradation. An extraction method is customarily required to extract the resistive component from the total leakage current. The existing methods to extract the resistive current are complex and less accurate. Therefore, this paper describes a simple and accurate circuit-based method to extract the resistive current using equivalent model and measured leakage current of the arrester. The accuracy of the proposed method is validated through experimental results on ABB’s 120 kV surge arrester, EMTP and QuickField software simulations. The performance of the method is also analyzed and verified experimentally on 72, 180 and 240 kV rated ABB’s surge arresters. The obtained results of resistive leakage current have shown the maximum error of 0.001%. Simple and easier computational steps with higher accuracy are the key benefits of the proposed technique.

Dark currents of unipolar barrier structures based on mercury cadmium telluride for long-wave inred detectors

2021 ◽  
pp. 3-8
Author(s):  
A.V. Voitsekhovskii ◽  
◽  
S.N. Nesmelov ◽  
S.M. Dzyadukh ◽  
S.A. Dvoretsky ◽  
...  
Keyword(s):  
Cadmium Telluride ◽  
Leakage Current ◽  
Current Density ◽  
Dark Current ◽  
Mercury Cadmium Telluride ◽  
Current Component ◽  
Long Wave ◽  
Dark Currents ◽  
Surface Leakage ◽  
Long Wave Infrared

Two types of long-wave infrared nBn structures based on mercury cadmium telluride grown by molecular beam epitaxy on GaAs (013) substrates have been fabricated. For each type of device, the side walls of the mesa structures were passivated with an Al2O3 dielectric film or left without passivation. The CdTe content in the absorbing layers was 0.20 and 0.21, and in the barrier layers, 0.61 and 0.63. The dark currents of the manufactured devices were studied in a wide range of voltages and temperatures. The values of the surface leakage component are found under various conditions. It has been shown that the surface leakage current density decreases upon passivation with an Al2O3 film. It was found that at room temperature in the fabricated nBn structures with reverse biases, the surface leakage component dominates, and with forward biases, the dark current is determined by the combined effect of the surface leakage component and the bulk current component. From the Arrhenius plots, the values of the activation energies of the surface leakage current component were found, which at small reverse biases are in the range from 0.05 to 0.10 eV. At small reverse biases, upon cooling the samples, the role of the bulk component of the dark current increases, which at 180 K is approximately 0.81 A/cm2. In the temperature range 200-300 K, the values of the dark current density exceed the values calculated according to the empirical Rule07 model by a factor of 10-100, which indicates the possibility of creating long-wave infrared barrier detectors with a decrease in the values of the surface leakage component.

scholarly journals Cooperative synchronization control of intelligent lifting systems with actuator failures

2018 ◽  
Vol 10 (12) ◽  
pp. 168781401881349
Author(s):  
Lijing Dong
Keyword(s):  
Data Transfer ◽  
Synchronization Error ◽  
Synchronization Control ◽  
Wireless Data ◽  
Hydraulic Actuators ◽  
Actuator Failures ◽  
Distributed Controller ◽  
Transfer Unit ◽  
Distributed Synchronization ◽  
Lifting System

Synchronization of a large-scale lifting system with hydraulic actuator failures is investigated in this article. The lifting system is composed of multiple intelligent lifting subsystems with hydraulic actuators, wireless data transfer unit, and distributed controller. During the lifting process, the hydraulic actuators are possible to be malfunctioned. Once actuator failure occurs, the number of lifting points and the communication topology would change over different time intervals. This article proposes a distributed synchronization control method and adopts switching technique in analyzing the lifting synchronization. The distributed controller is designed with information received from around subsystems through wireless data transfer unit rather than with direct reference signal from the control station. On the basis of Lyapunov stability theory and switched technique, sufficient conditions that guarantee the synchronization of the lifting system with actuator failures are achieved, and synchronization errors can be reduced as small as desired. Finally, the effectiveness of proposed distributed synchronization controller is verified by numerical simulations conducted on AMESim platform. From the simulation results, it can be seen that when actuator failures occur, the synchronization error of the remaining lifting subsystems is less than 5%. The lifting synchronization error shrinks to 5% in 5.87 s when a broke-down subsystem returns to normal.

scholarly journals Artificial Neural Network Application for Thermal Image Based Condition Monitoring of Zinc Oxide Surge Arresters

2017 ◽  
Vol 7 (3) ◽  
pp. 593
Author(s):  
Novizon Novizon ◽  
Zulkurnain Abdul-Malek ◽  
Aulia Aulia
Keyword(s):  
Neural Network ◽  
Artificial Neural Network ◽  
Leakage Current ◽  
Thermal Image ◽  
Histogram Method ◽  
Good Tool ◽  
Third Harmonic ◽  
Surge Arresters ◽  
Long Time ◽  
Artificial Neural

<p>Manual analysis of thermal image for detecting defects and classifying of condition of surge arrester take a long time. Artificial neural network is good tool for predict and classify data. This study applied neural network for classify the degree of degradation of surge arrester. Thermal image as input of neural network was segmented using Otsu’s segmentation and histogram method to get features of thermal image. Leakage current as a target of supervise neural network was extracted and applied Fast Fourier Transform to get third harmonic of resistive leakage current. The classification results meet satisfaction with error about 3%.</p>

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