A New Method to Monitor the Level of Contamination on Insulators Using PWT and PCA in Electrical Distribution Networks A New Method to Monitor the Level of Contamination on Insulators Using PWT and PCA in Electrical Distribution Networks (original) (raw)
Related papers
A new procedure for determination of insulators contamination in electrical distribution networks
International Journal of Electrical Power & Energy Systems, 2014
This paper presents a novel method for determination of insulator contamination (IC) level. ICs caused some problems in electric networks. Some faults occur in electric system due to ICs. These faults sometimes log to a sudden and serious damages to the systems. So ICs reduce power quality and reliability indexes. Usually insulator washing is a solution for this problem and its events. Insulators washing have a heavy cost and if a time table for their washing time can be planned, both time and cost will be saved. In this paper average insulators contamination calculated using line current. Leakage current on insulators surface are coming together with small arcs. These arcs have high frequency component. Proposed method extracts some features from these components using Discrete Wavelet Transform (DWT) and principal component analysis (PCA). Line current data gathered for six month on a 20 kV distribution feeder with 6.4 kHz sampling rate. Results show high accuracy of this method for determining of insulators contamination.
Classification of Leakage Current waveforms using Wavelet Packet Transform on high voltage insulator
2014 ICHVE International Conference on High Voltage Engineering and Application, 2014
In this paper, the Wavelet Packet Transform (WPT) for Leakage Current (LC) examination on high voltage insulators under pollution conditions is exposed. Based on laboratory experiments under various artificial solution natures (consisting in a mixture of distilled water with NaCl, Kaolin or Kieselguhr), LC acquisition is firstly carried out. After a careful examination, three groups of LC waveforms are constituted depending on their peak values. Then, WPT is used to decompose LC waveforms. From this decomposition, feature extraction by energy calculation is processed. Hence, a feature vector, composed of wavelet coefficients energies values, is used as input for three classification algorithms consisting in K-Nearest Neighbors, Naïve Bayes and Support Vector Machine, to distinguish between three LC groups. Indeed, this paper introduces WPT for LC investigation and classification.
2014 IEEE Conference on Electrical Insulation and Dielectric Phenomena (CEIDP), 2014
This paper expose a novel algorithm to monitor and classify the pollution severity level of insulators based on Leakage Current (LC) waveforms investigation. For this purpose, LC waveforms acquisition is firstly carried out on a plane insulator model under various saline pollution conductivities. Then, LC is investigated and decomposed in five levels using the Wavelet Packet Transform (WPT). Two, four, eight, sixteen and thirty-two coefficients are obtained from the first level to the fifth one respectively. Next, Standard Deviation-Multi Resolution Analysis (STD-MRA) is used to extract features from WPT coefficients. It is noted that the higher the pollution severity, the higher the STD value. Finally, STD values are used as inputs to three well known classification methods (K-Nearest Neighbors, Naïve Bayes and Support Vector Machines), while the sole output is the pollution conductivity value. Results announce that the higher the decomposition level, the better the classification performance. WPT methodology is presented as a highly efficient technique for LC investigation and classification.
An Evaluation of Alternative Techniques for Monitoring Insulator Pollution
IEEE Transactions on Power Delivery, 2009
Electrical utility companies are constantly seeking predictive techniques that indicate the appropriate moment for maintenance intervention, while aiming toward a continuous increase in service indices. This paper proposes the use of pattern-recognition techniques to build classifiers that diagnose the operational state of the insulation structure in an online application. Important results were achieved during the study, mainly related to the types of sensors and features that need to be applied during the diagnosis process. Ultrasound and current leakage sensors, very-high frequency antenna, and thermovision instruments were employed to acquire signals and images in order to construct recognition systems. A number of specific features were applied to verify their importance during the classification process. Features were obtained in the time, frequency, and wavelet domains. Two groups of pattern-recognition techniques were applied: linear (Fisher and Karhunen-Loève) and nonlinear (artificial neural network). The results indicated that pollution deposit can be evaluated by the proposed techniques, especially when a combination of sensors is employed.
IJERT-An Evaluation of Techniques for Monitoring the High Voltage Insulator Pollution
International Journal of Engineering Research and Technology (IJERT), 2015
https://www.ijert.org/an-evaluation-of-techniques-for-monitoring-the-high-voltage-insulator-pollution https://www.ijert.org/research/an-evaluation-of-techniques-for-monitoring-the-high-voltage-insulator-pollution-IJERTV4IS070074.pdf Leakage current monitoring associated with the method for measuring the pollution levels on High Voltage insulator of overhead transmission line. This paper describes the various pollution monitoring techniques of High Voltage insulator such as frequency characterization, pattern-recognition, optical detection of partial discharge, sensor system with satellite communication link etc. By using the combinations of sensors, processing techniques & electronics set up, the characteristics of the leakage current can be evaluated. Frequency characterization investigated with artificial contamination tests & field tests. Pattern recognition technique classifies the state of insulation structure in online application. The system comprises a fiber-optic sensor, directly connected to one insulator of the string that emits a sample of the leakage current waveform to a processing module via an optical link. Satellite based monitoring along with the Important results were achieved during the field implantation, mainly related to system design & features that need to be applied during the building of tower with transmission line of High Voltage. Experimental activities & field system records the relevant status of pollution level.
Contamination Level Monitoring Techniques for High-Voltage Insulators: A Review
Energies
Insulators are considered one of the most significant parts of power systems which can affect the overall performance of high-voltage (HV) transmission lines and substations. High-voltage (HV) insulators are critical for the successful operation of HV overhead transmission lines, and a failure in any insulator due to contamination can lead to flashover voltage, which will cause a power outage. However, the electrical performance of HV insulators is highly environment sensitive. The main cause of these flashovers in the industrial, agricultural, desert, and coastal areas, is the insulator contamination caused by unfavorable climatic conditions such as dew, fog, or rain. Therefore, the purpose of this work is to review the different methods adopted to identify the contamination level on high-voltage insulators. Several methods have been developed to observe and measure the contamination level on HV insulators, such as leakage current, partial disgorgement, and images with the help of ...
2012 4th International Conference on Intelligent and Advanced Systems (ICIAS2012), 2012
The measurement and analysis of leakage current (LC) for condition-based monitoring and as a means of predicting flashover of polluted insulators has attracted a lot of research in recent years. Leakage current plays an important role in the detection of insulator's condition. This paper proposes a method for reducing the noise included in the current signal. The tests were carried out on cleaned and polluted glass insulators by using surface tracking and erosion test procedure of IEC 60587.Wavelet analysis method is used to compress the leakage current data. Experimental results shows that the actual signals of leakage current are related to the levels of insulator contamination.
2013 IEEE International Conference on Solid Dielectrics (ICSD), 2013
The objective of our study is to analyse the ac applied voltage signals recorded for different pollution levels using a following technique: wavelet packet analysis. Laboratory tests were performed on flat plate models of glass (500x500x5 mm) under uniform pollution. The plate models were sprayed with a solution prepared by mixing 100 g of kaolin in one liter of distilled water. An appropriate amount of NaCl was added to the slurry to give required Equivalent Salt Deposit Density (ESDD). The various studied ESDD are as follows: 1.2, 3.5, 6, 10, 15 and 20 mS/cm. The obtained results show that this technique constitutes a very effective tool to estimate the pollution severity degree on outdoor insulation surface.
The Severity of Polluted Insulator Surface Based on the Leakage Current Harmonic Measurements
Atlantis Highlights in Engineering, 2021
One of the important components in the high voltage overhead lines placed on the transmission tower is an insulator. Insulators that are installed outdoor will be exposed to the environment directly. Due to environmental conditions and pollutants attached to the surface, leakage currents can flow on the surface of the insulator. Large leakage currents can damage the surface of the insulator and cause losses in the form of heat and even cause flashover. This paper provides an alternative way to prevent early flashover by detecting the severity of the insulator surface based on harmonic measurements of leakage currents. Insulator performance mainly depends on the conductivity of the surface layer being polluted or by generating pollutants via the equivalent salt deposit density (ESDD). The leakage currents were evaluated at different ESDD levels as deposits of very light, light, moderate, and heavy NaCl salt pollution on a 20 kV outdoor polymer insulators. From the experiments, it can be concluded that: i. The leakage current that occurs when the surface of the insulator is very lightly polluted has an unsymmetrical waveform that is distorted and leads to a positive with a large THD; ii. The magnitude of the leakage current with the surface of the insulator is polluted, which leads to greater weight, but the harmonic distortion and THD are getting smaller with the waveform of the leakage current signal leading to a sinusoidal waveform.
Estimation of the Insulator Pollution Level Based on Frequency Characteristics of Leakage Current
CIGRE, 2015
One of the major problems in electric power transmission and distribution systems is the flashover caused by polluted insulators. This type of flashover is known as temporary fault that can turn into a permanent fault, causing sustained interruption [1]. Cost of power interruptions is highly significant for consumers and utility companies. For example, U.S. electric power interruptions, cost $135 billion per year [2]. Polluted insulators also contribute to the leakage current in a transmission line system. The dissipation of power due to leakage current is significant. The leakage current increases with pollution conductivity, and result in rapid extension of partial arcs [3, 4]. It is important to evaluate the contamination level of energized insulators to prevent unexpected pollution flashover and improve the reliability of the system. When the pollution level of in-service insulators are identified, the appropriate decision can be made about period of washing the insulators. In this study, a leakage current waveform characteristics is used in order to predict the severity of the contamination on the surface of insulators. The phase angle difference, total harmonic distortion (THD), and rate of rise of THD are the leakage current characteristics used for monitoring the pollution level. The values of the phase angle difference () between applied voltage and the fundamental frequency of the leakage current are computed while the pollution conductivity increases. When the pollution conductivity is low, the leakage current is capacitive. On the other hand, the leakage current becomes resistive when the pollution conductivity is high enough. The total harmonic distortion (THD) of leakage current is used for detection of contamination severity. The high frequency components of the leakage current increase with pollution conductivity and affect the THD level. Furthermore, the harmonic level variation of the leakage current over time results in THD variation. The rate of rise of THD (RRTHD) is introduced as an effective parameter to find the pollution level. These details provide a good correlation between the state of pollution and the leakage current. Therefore, phase angle difference (), THD, and RRTHD are used as the characteristic parameters of leakage current in order to find the contamination level.