System and method for detection of surface tracking degradation in high voltage polymeric insulators

Abstract

Disclosed herein is a system (400) to detect surface tracking degradation in high voltage polymeric insulators. The system comprises an insulator (406) coupled to a high voltage transformer (402) and an Optical Emission Spectroscopy (OES) module (416). The OES module (416) comprises a telescope (418) configured to collect an optical emission during one or more stages of discharge of the insulator (406). The OES module (416) further comprises a spectrometer (420) configured to acquire an emission spectrum by analyzing one or more optical characteristics of the collected optical emission during the one or more stages of discharge and an optical fiber (422) configured to connect the telescope (418) and a spectrometer (420). Further the system comprises a control module (424) configured to detect surface tracking degradation by analyzing dominant peaks in the acquired emission spectrum.

Description

SYSTEM AND METHOD FOR DETECTION OF SURFACE TRACKING DEGRADATION IN HIGH VOLTAGE POLYMERIC INSULATORS TECHNICAL FIELD

[0001] The embodiments of the present disclosure generally relate to the field of insulators. More particularly, the present disclosure relates to a system and method for detection of surface tracking degradation in high voltage polymeric insulators.BACKGROUND OF THE INVENTION

[0002] The subject matter disclosed in the background section should not be assumed or construed to be prior art merely because of its mention in the background section. Similarly, any problem statement mentioned in the background section or its association with the subject matter of the background section should not be assumed or construed to have been previously recognized in the prior art.

[0003] In recent years, silicone rubber-based high voltage insulators have been an outstanding replacement for toughened glass and porcelain insulators due to their favorable dielectric properties, exceptional hydrophobicity, effective pollution resistance, lightweight nature, and cost effectiveness. However, challenges arise while using the silicone rubber-based high voltage insulators for outdoor environment as they are prone to degradation due to harsh environments. Tracking is considered as one of the primary root causes for the failure of the high voltage insulators in the outdoor environment. The issue of the tracking occurs due to deposition of pollution on surface of the high voltage insulators. The tracking is defined as a formation of carbonaceous conductive path on the surface of the high voltage insulators. The formation of the carbonaceous conductive path on the surface results in damage to the surface of the high voltage insulators, leading to bridging of high voltage point and the ground. The bridging causes interruption in an operation of a power system. Once tracking takes place, the insulation properties are permanently compromised and cannot be restored. Therefore, there lies a needfor early detection of the tracking in the high voltage insulators for the outdoor environment.

[0004] To assess the tracking and erosion performance of silicone rubber insulating material, industries and laboratories utilize an International Electrotechnical Commission (TEC) 60587 standard. The standard specifies a critical voltage of 2.5 kV for moderate conditions and 4.5 kV for tougher stresses. The standard also outlines failure criteria, such as leakage current not exceeding 60 mA and tracked path not exceeding 2.5 cm. However, visual inspection of the tracking in the silicone rubber insulating material may lead to misinterpretation. The standard identifies four stages of discharges such as, a surface discharge, a dry band formation, a localized bright spot, and the tracking. The formation of the localised bright spot is the crucial stage, as the spot is a precursor to the tracking. If the localized bright spot is undetected in early stage, the spot rapidly progresses to the tracking, leading to a permanent conductive path. This in turn causes the failure of the high voltage insulators, leading to infrastructure damage of the power system. Traditional methods such as leakage current analysis and thermal image analysis often fail to identify a transitional phase from the localized bright spot to the tracking.

[0005] FIG. 1 illustrates sample insulator photographs at different stages of discharges during the leakage current analysis, in accordance with a prior art. Leakage current is measured during an experimental analysis of the sample insulator using a current measurement system, for example, a Tektronix TCP312A current probe. The leakage current of the sample insulator is measured during the four stages of the discharges. The four stages include the surface discharge (Fig. la), the dry band formation (Fig. lb), the localized bright spot (Fig. 1c), and the tracking (Fig. Id). The surface discharge is continuous but low intense discharge caused by contaminant flow. A constant surface discharge will eliminate moisture on the surface of the sample insulator, leading to the dry band formation. Over a period, due to salt water (NH4CI) logging near a ground electrode of the sample insulator, the localized bright spot will occur. The localized bright spot is a direct indication of the pre-occurrence of the tracking. The four stages represent insulatordeterioration, which is crucial for evaluating material condition and ensuring electrical system reliability and safety.

[0006] FIG.2 illustrates an experiment result depicting the leakage current analysis and a corresponding Fast Fourier Transform (FFT) analysis of the different stages of discharges, in accordance with the prior art. As illustrated in Fig. 2, the leakage current analysis and the corresponding FFT analysis of the sample insulator reveals distinct features across the four stages of discharges. In surface discharge (Fig. 2a (i) & Fig. 2b (i)), a 150 Hz peak emerged alongside a distorted waveform. The elimination of the moisture on the surface of the sample insulator leads to the dry band formation on the sample insulator. During the presence of dry bands, there is no formation of arcing. The leakage current analysis and the corresponding FFT analysis of the dry band formation (Fig. 2a (ii) & Fig. 2b (ii)) amplified a FFT peak and introduced sub-harmonics.

[0007] The leakage current analysis and the corresponding FFT analysis of the localized bright spot (Fig. 2a (iii) & Fig. 2b (iii)) comprise strong arcs, an asymmetric waveform, and odd harmonics at 150, 250, and 350 Hz. The leakage current analysis and the corresponding FFT analysis of the tracking (Fig. 2a (iv) & Fig. 2b (iv)) exhibited a sinusoidal waveform with a large phase shift and only the fundamental 50 Hz peak due to the purely resistive nature of the sample insulator. The experimental analysis of the sample insulator found no significant difference in leakage current between an initial stage of the surface discharge and the stage of the localized bright spot, except for the higher magnitude of leakage current during the stage of the localized bright spot. This suggests that leakage current alone may not be a reliable indicator for distinguishing between the surface discharge and the localized bright spot. Consequently, relying solely on leakage current may lead to missed or delayed identification of critical transitions, such as the onset of the tracking. Therefore, there is a need for more robust diagnostic tools to accurately detect and characterize early-stage degradation in the high voltage insulators.

[0008] FIG.3 illustrates an experimental Infrared (IR) image depicting the different stages of discharges during the thermal image analysis of the sample insulator, in accordance with the prior art. The thermal image analysis of the high voltage insulators is performed by an experimental analysis of the high voltage insulators using a thermal imaging camera. The thermal imaging camera such as Forward-Looking Infrared (FLIR) camera (FLIR E95 IR) is utilized in the experiment to understand temperature variation of each stage of discharge of the sample insulator. Fig. 3 shows a thermal profile obtained at different stages during the experimental analysis of the sample insulator. During the surface discharge stage of discharge (Fig. 3a), a continuous arcing of moderate intensity localized to specific points occurred, covering up to 120°C around the arcing point, with an average temperature range of 80°C to 100°C. In the dry band formation stage of discharge (Fig. 3b), since there is no current flow, no arcing occurred within the dry band region, maintaining a relatively flat temperature around 105°C, close to a sample temperature.

[0009] The localized bright spot stage of discharge (Fig. 3 c) exhibited an inception of a hot spot originating from the ground electrode, reaching a peak temperature of 620°C. Identifying the formation of the localized bright spot is very crucial for further detection of the tracking. The silicone rubber insulating material depolymerize around 500°C. At this point, the insulating material may start to depolymerize, leading to the formation of smaller cyclic siloxanes and other byproducts through mechanisms such as radical scission of Si-C bond. An intensified localized bright spot led to increased heat and the formation of an initial tracking path. During the tracking stage of discharge (Fig. 3d), there was a gradual expansion of the tracking path with continuous arcing and Joule heating, resulting in temperature peaks reaching up to 1200°C due to sustained arcing and erosion flame. The consolidated observations on the thermal image analysis provide a comprehensive insight into the thermal dynamics at each stage of discharge to analyse the degradation mechanisms of a silicone rubber insulator under high voltage electrical stress. The thermal image analysis showcases the progression ofheat generation and localization during the experiment. However, the thermal image analysis fails to effectively identify the transitional phase from the localized bright spot to the tracking.

[0010] Therefore, there is a need for an improved system and method for efficient detection of the tracking in the high voltage insulators.SUMMARY

[0011] The following embodiments present a simplified summary to provide a basic understanding of some aspects of the disclosed invention. This summary is not an extensive overview, and it is not intended to identify key / critical elements or to delineate the scope thereof. Its sole purpose is to present some concepts in a simplified form as a prelude to the more detailed description that is presented later.

[0012] In an embodiment, a system to detect surface tracking degradation in high voltage polymeric insulators is disclosed. The system includes an insulator coupled to a high voltage transformer and an Optical Emission Spectroscopy (OES) module. The OES module includes a telescope configured to collect an optical emission during one or more stages of discharge of the insulator. The OES module further includes a spectrometer configured to acquire an emission spectrum by analyzing one or more optical characteristics of the collected optical emission during the one or more stages of discharge and an optical fiber configured to connect the telescope and a spectrometer. The system further includes a control module configured to detect surface tracking degradation by analyzing dominant peaks in the acquired emission spectrum.

[0013] According to some aspect of the present disclosure, the one or more stages of discharge includes at least one of a surface discharge, a dry band formation, a localized bright spot, and the tracking, and represents a progressive insulation degradation property of the polymeric insulators.

[0014] According to some aspect of the present disclosure, the spectrometer is configured to analyze the one or more optical characteristics of the optical emission over a spectral wavelength range of 197 nm to 1000 nm encompassing Ultraviolet (UV) region, visible region, and Near-Infrared (NIR) regions.

[0015] According to some aspect of the present disclosure, the OES module is configured to detect one or more elements in the polymeric insulators by measuring the optical emission of the insulator due to excitation of atoms or ions.

[0016] According to some aspect of the present disclosure, the one or more optical characteristics includes at least one of a peak wavelength, a peak intensity, an Area Under Curve (AUC), a Full Width at Half Maximum (FWHM), and a bandgap energy (eV).

[0017] In another embodiment, disclosed herein is a method for detecting surface tracking degradation in high voltage polymeric insulators. The method includes collecting, by a telescope of an Optical Emission Spectroscopy (OES) module, an optical emission during one or more stages of discharge of the insulator. The method further includes acquiring, by a spectrometer of the OES module, an emission spectrum by analyzing one or more optical characteristics of the collected optical emission during the one or more stages of discharge. Further, the method includes detecting, by a control module, the surface tracking degradation by analyzing dominant peaks in the acquired emission spectrum.

[0018] In another embodiment, a system to detect surface tracking degradation in high voltage polymeric insulators is disclosed. The system includes an insulator coupled to a high voltage transformer and an optical fluorescence fiber sensor. The optical fluorescence fiber sensor includes an optical fluorescence fiber located alongside of the insulator. The optical fluorescence fiber is configured to collect an optical emission during one or more stages of discharge of the insulator and generate one or more fluorescence signals based on the optical emission during the one or more stages of discharge. The optical fluorescence fiber sensor includes a photomultiplier module including a photodetector. The photodetector is configuredto detect the one or more fluorescence signals from the optical fluorescence fiber. Further, the system includes a control module configured to detect the surface tracking degradation by analyzing the one or more fluorescence signals.

[0019] According to some aspect of the present disclosure, the one or more stages of discharge includes at least one of a surface discharge, a dry band formation, a localized bright spot, and the tracking, and represents a progressive insulation degradation property of the polymeric insulators.

[0020] According to some aspect of the present disclosure, the optical fluorescence fiber is embedded with multiple fluorescence molecules.

[0021] According to some aspect of the present disclosure, the one or more fluorescence signals are guided through the optical fluorescence fiber by total internal reflection.

[0022] According to some aspect of the present disclosure, the optical fluorescence fiber sensor is configured to detect one or more temporal variations of the one or more stages of discharge based on one or more signal parameters of the one or more fluorescence signals.

[0023] According to some aspect of the present disclosure, the one or more signal parameters of the one or more fluorescence signals comprise at least one of a rise time, a pulse width, an energy, and a peak amplitude.

[0024] In another embodiment, disclosed herein is a method for detecting surface tracking degradation in high voltage polymeric insulators. The method includes collecting, by an optical fluorescence fiber, an optical emission during one or more stages of discharge of the insulator. The method further includes generating, by the optical fluorescence fiber, one or more fluorescence signals based on the optical emission during the one or more stages of discharge. Further, the method includes detecting, by a photomultiplier module, the one or more fluorescence signals from the optical fluorescence fiber. Furthermore, the method includes detecting, by acontrol module, the surface tracking degradation by analyzing the one or more fluorescence signals.BRIEF DESCRIPTION OF DRAWINGS

[0025] Various embodiments disclosed herein will become better understood from the following detailed description when read with the accompanying drawings. The accompanying drawings constitute a part of the present disclosure and illustrate certain non-limiting embodiments of inventive concepts. Further, components and elements shown in the drawings are not necessarily to scale, emphasis instead being placed upon clearly illustrating the principles of the present disclosure. For consistency and ease of understanding, similar components and elements are annotated by reference numerals in the exemplary drawings.

[0026] FIG. 1 illustrates sample insulator photographs at different stages of discharges during leakage current analysis of a sample insulator, in accordance with a prior art.

[0027] FIG.2 illustrates an experiment result depicting the leakage current analysis and a corresponding Fast Fourier Transform FFT analysis of the different stages of discharges, in accordance with the prior art.

[0028] FIG.3 illustrates an experimental Infrared (IR) image depicting the different stages of discharges during thermal image analysis of the sample insulator, in accordance with the prior art.

[0029] FIG. 4 illustrates a schematic representation of a system to detect surface tracking degradation in high voltage polymeric insulators using an Optical Emission Spectroscopy (OES), in accordance with an embodiment of the present disclosure.

[0030] FIG. 5 illustrates a process flow diagram depicting an experimental methodology of an inclined plane test, in accordance with an embodiment of the present disclosure.

[0031] FIG. 6 illustrates a process flow diagram depicting a method for detecting the surface tracking degradation in the high voltage polymeric insulators using the OES, in accordance with an embodiment of the present disclosure.

[0032] FIG.7 illustrates a waveform depicting a wavelength spectral shift observed during the inclined plane test, in accordance with an embodiment of the present disclosure.

[0033] FIG. 8 illustrates a spectra depicting an optical emission wavelength spectrum at the different stages of discharges, in accordance with an embodiment of the present disclosure.

[0034] FIG. 9 illustrates a bar graph depicting variation of a peak wavelength and a bandgap energy for the different stages of discharges, in accordance with an embodiment of the present disclosure.

[0035] FIG. 10 illustrates a scatter plot depicting t-Distributed Stochastic Neighbour Embedding t-SNE 3-dimensional (3D) visualization of features of the OES, in accordance with an embodiment of the present disclosure.

[0036] FIG. 11 illustrates a schematic representation of a system to detect surface tracking degradation in high voltage polymeric insulators using an optical fluorescence fiber sensor, in accordance with an embodiment of the present disclosure.

[0037] FIG. 12 illustrates a process flow diagram depicting a method for detecting the surface tracking degradation in the high voltage polymeric insulators using the optical fluorescence fiber sensor, in accordance with an embodiment of the present disclosure.

[0038] FIG. 13 illustrates a waveform depicting one or more fluorescence signals at the different stages of discharges, in accordance with an embodiment of the present disclosure.

[0039] FIG. 14 illustrates a scatter plot depicting t-SNE 3D visualization of features of the one or more fluorescence signals, in accordance with an embodiment of the present disclosure.DETAILED DESCRIPTION

[0040] Inventive concepts of the present disclosure will now be described more fully hereinafter with reference to the accompanying drawings, plots, and photographs in which examples of one or more embodiments of inventive concepts are shown. Inventive concepts may, however, be embodied in different forms and should not be construed as limited to the embodiments set forth herein. Further, the one or more embodiments disclosed herein are provided to describe the inventive concept thoroughly and completely, and to fully convey the scope of each of the present inventive concepts to those skilled in the art. Furthermore, it should be noted that the embodiments disclosed herein are not mutually exclusive concepts. Accordingly, one or more components from one embodiment may be tacitly assumed to be present or used in any other embodiment.

[0041] The following description presents various embodiments of the present disclosure. The embodiments disclosed herein are presented as teaching examples and are not to be construed as limiting the scope of the present disclosure. The present disclosure should in no way be limited to the illustrative implementations, drawings, and techniques illustrated below, including the exemplary design and implementation illustrated and described herein, but may be modified, omitted, or expanded upon without departing from the scope of the present disclosure.

[0042] The following description contains specific information pertaining to embodiments in the present disclosure. The detailed description uses the phrases “in some embodiments” or “some implementations” which may each refer to one or more or all of the same or different embodiments or implementations. The term “some” as used herein is defined as “one, or more than one, or all.” Accordingly, the terms “one,” “more than one,” “more than one, but not all” or “all” would all fall under the definition of “some.” In view of the same, the terms, for example, “inan embodiment” or “in an implementation” refers to one embodiment or one implementation and the term, for example, “in one or more embodiments” refers to “at least one embodiment, or more than one embodiment, or all embodiments ”. Further, the term, for example, “in one or more implementations” refers to “at least one implementation, or more than one implementation, or all implementations.

[0043] The term “comprising,” when utilized, means “including, but not necessarily limited to;” it specifically indicates open-ended inclusion in the so-described one or more listed features, elements in a combination, unless otherwise stated with limiting language. Furthermore, to the extent that the terms “includes,” “has,” “have,” “contains,” and other similar words are used in either the detailed description, such terms are intended to be inclusive in a manner similar to the term “comprising.”

[0044] In the following description, for the purposes of explanation, various specific details are set forth in order to provide a thorough understanding of embodiments of the present disclosure. It will be apparent, however, that embodiments of the present disclosure may be practiced without these specific details. Several features described hereafter can each be used independently of one another or with any combination of other features.

[0045] The description provided herein discloses exemplary embodiments only and is not intended to limit the scope, applicability, or configuration of the present disclosure. Rather, the foregoing description of the exemplary embodiments will provide those skilled in the art with an enabling description for implementing any of the exemplary embodiments. Specific details are given in the following description to provide a thorough understanding of the embodiments. However, it may be understood by one of the ordinary skilled in the art that the embodiments disclosed herein may be practiced without these specific details.

[0046] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the disclosure. As usedherein the description, the singular forms "a", "an", and "the" include plural forms unless the context of the invention indicates otherwise.

[0047] The terminology and structure employed herein are for describing, teaching, and illuminating some embodiments and their specific features and elements and do not limit, restrict, or reduce the scope of the present disclosure. Accordingly, unless otherwise defined, all terms, and especially any technical and / or scientific terms, used herein may be taken to have the same meaning as commonly understood by one having ordinary skill in the art.

[0048] Embodiments of the present disclosure will be described below in detail with reference to the accompanying figures. FIG. 1 to FIG. 14, discussed below, and the one or more embodiments used to describe the principles of the present disclosure are by way of illustration only and should not be construed in any way to limit the scope of the present disclosure. Those skilled in the art will understand that the principles of the present disclosure may be implemented in any suitably arranged system or device.

[0049] Further, a few of the figures in the accompanying drawings are represented in color for accurate illustration of results. The color drawings illustrate one or more results which cannot be adequately represented in black and white or gray scale. The color drawings are therefore necessary to ensure proper interpretation of the disclosed invention.

[0050] Various aspects of the present disclosure provide a system and a method for detection of surface tracking degradation in high voltage polymeric insulators.

[0051] In one or more aspects, the system and the method utilize an Optical Emission Spectroscopy (OES) and an optical fluorescence fiber sensor for detecting the surface tracking degradation in the high voltage polymeric insulators.

[0052] In one or more aspects, the system and the method utilize one or more optical characteristics and one or more signal parameters to detect the surface tracking degradation in the high voltage polymeric insulators.

[0053] FIG. 4 illustrates a schematic representation of a system 400 to detect surface tracking degradation in high voltage polymeric insulators using the OES, in accordance with an embodiment of the present disclosure.

[0054] The system 400 illustrates the schematic representation of an experimental setup of Inclined Plane Test (IPT) to simulate real time discharges on the high voltage polymeric insulators under laboratory conditions. The system 400 may comprise, an insulator 406, an OES module 416, and a control module 424.

[0055] In one embodiment, the insulator 406 may be a sample insulator made up of silicone rubber. The insulator 406 may be coupled to a high voltage transformer 402. The insulator 406 may be subjected to AC high voltage following an International Electrotechnical Commission (TEC) 60587 standard. A pair of stainless-steel electrodes may be mounted on the surface of the insulator 406. The bottom electrode may be a ground electrode 408 connected to the ground, and the top electrode may be High Voltage (HV) electrode 410. The HV electrode 410 may be protected by a current limiting resistor 404 from the high voltage transformer 402. The insulator 406 may be placed in a downward direction tilted at a 45 -degree angle to the horizontal. For experimental purposes, the insulator 406 may be polluted by adding contaminants / pollutants. In a non-limiting example, ammonium chloride (NH4C1) solution with a conductivity of 2.5 mS / cm may be utilized as the pollutant at flow rate of 0.6ml / min. The pollutant may be stored in a container 414. Aperistaltic pump 412 may be used to pump the pollutant towards the insulator 406. The pollutant may be streamed down over the insulator 406 for 15 mins before applying a test voltage of 4.5 kV on the insulator 406. During the experiment, a leakage current of the insulator 406 may be measured using a current probe.

[0056] In some aspects of the present disclosure, the IPT experiment setup may be employed with the OES module 416 to detect light emitted by discharges on theinsulator 406 and to understand the optical characteristics of the discharges. The OES module 416 may comprise a telescope 418, a spectrometer 420, and an optical fiber 422. The telescope 418 may be configured to collect an optical emission during one or more stages of discharge of the insulator 406. In a non-limiting example, the telescope 418 may be a Newtonian telescope. The one or more stages of discharge comprises at least one of a surface discharge, a dry band formation, a localized bright spot, and the tracking. The one or more stages of discharge may represent a progressive insulation degradation property of the polymeric insulators.

[0057] The spectrometer 420 may be configured to acquire an emission spectrum by analyzing one or more optical characteristics of the collected optical emission during the one or more stages of discharge. The optical fiber 422 may be configured to connect the telescope 418 and a spectrometer 420. The control module 424 may be configured to detect surface tracking degradation by analyzing dominant peaks in the acquired emission spectra.

[0058] FIG. 5 illustrates a process flow diagram 500 depicting an experimental methodology of the IPT, in accordance with an embodiment of the present disclosure.

[0059] As shown in FIG. 5, during the IPT, the one or more stages of the discharges of the insulator 406 may occur. The one or more stages may include a surface discharge, a dry band formation, a localized bright spot, and a tracking. The surface discharge may occur due to contaminant flow, the dry band formation may disrupt current flow, the localized bright spot may cause extreme heating, and the tracking may result in permanent insulation failure due to a carbonized path. The four stages may represent the progressive insulation degradation property of the insulator 406. The IPT may be carried out to observe the four stages of the discharge and to detect the tracking stage of the discharge. The present disclosure may utilize the OES and an optical fluorescence fiber as probing optical techniques to analyze optical and spectral characteristics of the optical emission of the insulator 406 for early detection of the tracking stage.

[0060] FIG. 6 illustrates a process flow diagram depicting a method 600 for detecting the surface tracking degradation in the high voltage polymeric insulators using the OES, in accordance with an embodiment of the present disclosure. The method 600 comprises a series of operation steps indicated by blocks 602 through 606.

[0061] At block 602, the telescope 418 may collect the optical emission during the one or more stages of discharge of the insulator 406.

[0062] At block 604, by the spectrometer 420 may acquire an emission spectrum by analyzing one or more optical characteristics of the collected optical emission during the one or more stages of discharge.

[0063] At block 606, the control module 424 may detect the surface tracking degradation by analyzing dominant peaks in the acquired emission spectra.

[0064] In some aspects of the present disclosure, the spectrometer 420 may be configured to analyze the one or more optical characteristics of the optical emission over a spectral wavelength range of 197 nm to 1000 nm encompassing Ultraviolet (UV) region, visible region, and Near-Infrared (NIR) regions.

[0065] In some aspects of the present disclosure, the one or more optical characteristics may comprise at least one of a peak wavelength, a peak intensity, an Area Under Curve (AUC), a Full Width at Half Maximum (FWHM), and a bandgap energy (eV).

[0066] FIG. 7 illustrates a waveform 700 depicting a wavelength spectral shift observed during the IPT, in accordance with an embodiment of the present disclosure. The OES module 416 may be configured to detect one or more elements in the polymeric insulators by measuring the optical emission of the insulator 406 due to excitation of atoms or ions. When energy is applied, electrons in an insulating material may be promoted to higher energy levels, releasing photons at characteristic wavelengths.

[0067] In some aspects of the present disclosure, the spectrometer 420 may be utilized to acquire the emission spectra. In a non-limiting example, the emission spectra may be acquired using an Ocean Optics QE Pro spectrometer, which operates over a spectral wavelength range of 197 nm to 1000 nm. The broad wavelength range may enable the spectrometer 420 to capture both the UV, visible light and the NIR emissions associated with the different discharge phenomena on the insulating material, for example silicon rubber. The emission spectra may be acquired for the one or more stages of discharge during the IPT. An average of 100 spectra may be depicted for enhanced visualization. From FIG 7, it may be inferred that the dry band stage is be temporary and may not necessarily indicate severe degradation but rather a pause in conductive activity. Since there is no active arcing or significant ionization, optical emissions during the dry band stage are minimal.

[0068] FIG. 8 illustrates the spectra 800 depicting an optical emission wavelength spectrum at the different stages of discharges, in accordance with an embodiment of the present disclosure. As shown in FIG. 8, the stages such as the surface discharge, the localized bright spot, and the tracking shows different spectral characteristics and intensity levels. As shown in FIG. 8 (a), during the surface discharge stage, dominant peaks were observed around 300nm to 400 nm confirming the presence of the UV light emission and insulation property of the insulating material. As shown in FIG. 8 (b), the localized bright spot stage emitting orange color showed a dominant peak around 600 nm. This range of wavelength belongs to region of visible spectrum of yellowish orange light indicating semi-conducting property of the insulating material.

[0069] As shown in FIG. 8 (c), during the tracking stage, a significant rise in spectrum is observed from 400nm to lOOOnm with higher intensity. A peak wavelength of 910nm was observed in the NIR range. FIG. 8 (c) indicates that tracking is an intense high energy phenomenon involving wide range of wavelengths but peak wavelength emission at NIR and thermal radiation emission due to carbonization of the insulating material increases conducting property of the insulating material. Spectral shift observed during the one or more stages ofdischarge may aid to evaluate the performance of the insulator 406. To analyze the property of the optical emission during the one or more stages of discharge, the bandgap energy (eV) is calculated with the help of the OES spectra. The bandgap energy of light with optical emission wavelength spectra may be calculated as shown in Equation 1 :heE = eV (1)-peakwhere E is a photon energy, h is Planck's constant (6.626 x 10-34 J s), c is the speed of light (3 x 108 m / s), andpeakis the peak wavelength.

[0070] FIG.9 illustrates a bar graph 900 depicting variation of the peak wavelength and the bandgap energy for the different stages of discharges, in accordance with an embodiment of the present disclosure. The change in bandgap energy of the insulating material and variation in peak emission wavelength for the one or more stages such as the surface discharge, the localized bright spot, and the tracking is plotted in FIG. 9. The reduction in bandgap energy across the different stages of discharges provides a strong indication of degradation of the insulating material. Insulators typically have a large bandgap, preventing the free flow of charge carriers. However, as the insulating material undergoes high-energy discharge phenomena, the energy structure of the material is altered, leading to a reduction in the bandgap.

[0071] As shown in FIG. 9, during the surface discharge stage, the bandgap energy is 3.75 eV which indicates that the insulating material remains in insulated state. During the dry band stage (not shown), there is no intense heating or material breakdown, resulting in relatively unchanged bandgap. A decrease in bandgap energy to 2.1 eV during the localized bright spot stage confirms localized heating and ionization, causing partial conductivity. A significant drop in bandgap energy (1.37 eV) during tracking suggest considerable thermal and electrical stresses, causing a breakdown of the properties of the insulating material. The narrow bandgap allows charge carriers to migrate from a valence band to a conduction band,resulting in partial conductivity and increasing the exposure of the insulating material to further degradation.

[0072] FIG. 10 illustrates a scatter plot 1000 depicting t-Distributed Stochastic Neighbour Embedding (t-SNE) 3-dimensional (3D) visualization of features of the OES, in accordance with an embodiment of the present disclosure.

[0073] In some aspects of the present disclosure, feature extraction is essential for effective understanding and analysis of a high dimensional optical emission wavelength spectra. The one or more optical characteristics or spectral features such as the peak wavelength (nm), the peak intensity, the AUC, the FWHM and the bandgap energy (eV) may be analysed for better understanding of the emission characteristics. The spectral features may provide crucial insights into the energetic characteristics of the discharges. To effectively visualize the high-dimensional data, a t-SNE plot is employed for dimensionality reduction and 3D visualization.

[0074] As shown in FIG. 10, the 3D t-SNE plot clearly demonstrated distinct clustering of the three stages of discharge such as the surface discharge, the localized bright spot, and the tracking. Each stage formed well -separated clusters, providing strong evidence of the ability of the OES module 416 to accurately differentiate between the different discharge types based on their spectral features. The clustering validates that the optical emission wavelength spectra, when combined with appropriate feature extraction and advanced visualization techniques, is a robust and precise method for early detection of the surface tracking degradation in the high voltage polymeric insulators.

[0075] FIG. 11 illustrates a schematic representation of a system 1100 to detect surface tracking degradation in high voltage polymeric insulators using the optical fluorescence fiber sensor, in accordance with an embodiment of the present disclosure.

[0076] The system 1100 may comprise the insulator 406, the optical fluorescence fiber sensor 1102, and a control module 1108. The optical fluorescence fiber sensor1102 may comprise an optical fluorescence fiber 1104 and a photomultiplier module 1106 including a photodetector. The optical fluorescence fiber 1104 may be located alongside of the insulator 406.

[0077] In some embodiments, the IPT experiment setup may be employed with the optical fluorescence fiber sensor 1102 to detect light emitted by discharges on the insulator 406. The insulator 406 contaminated by the pollutant may emit light when the high voltage from the high voltage transformer 402 is passed through the HV electrode 410 and the ground electrode 408 on the insulator 406. The emitted light may be detected by the optical fluorescence fiber sensor 1102 for detecting the surface tracking degradation in the insulator 406. The optical fluorescence fiber 1104 may be configured to collect an optical emission during the one or more stages of discharge of the insulator 406. Further, the optical fluorescence fiber 1104 may be configured to generate one or more fluorescence signals based on the optical emission during the one or more stages of discharge. The photomultiplier module 1106 may comprise the photodetector. The photodetector may be configured to detect the one or more fluorescence signals from the optical fluorescence fiber 1104. The control module 1108 may be configured to detect the surface tracking degradation by analyzing the one or more fluorescence signals.

[0078] In some aspects of the present disclosure, the system 400 may utilize the optical fluorescence fiber 1104 as a green-fluorescent fiber with a polystyrene core and a polymethyl methacrylate (PMMA) cladding. The optical fluorescence fiber 1104 may be positioned 15 cm below the inclined sample of the insulator 406. In a non-limiting example, the optical fluorescence fiber sensor 1102 may comprise a photomultiplier module 1106. For example, the photomultiplier module 1106 may be a Silicone Photo Multiplier (SIPM) (microFC SMA 10050) module with a 30 V DC bias voltage and a highly sensitive photodetector used to capture emitted light from the insulator 406. The photodetector may be connected to a control module 1108. In some aspect, the photodetector may be connected to a digital oscilloscope. The optical fluorescence fiber 1104 may be 30 cm-long with one end connected to an active area of the photomultiplier module 1106. For precision, an output voltageof the photomultiplier module 1106 may undergo pre-amplification using an Agilent 8447D amplifier.

[0079] In some aspects of the present disclosure, a thermal camera (not shown) may be used to analyse temperature variation throughout the experiment. The thermal imaging camera such as Forward-Looking Infrared (FLIR) camera (FLIR E95 IR) with 76,800-pixel resolution and 0.05°C sensitivity may be utilized in the experiment to understand the temperature variation of each stage of discharge of the insulator 406. IR images of the surface of the insulator 406 may be taken every 10 minutes for a duration of 60-seconds. A straight line is drawn from the midpoint of the HV electrode 410 to the midpoint of the ground electrode 408, representing a path of the pollutant as a Region of Interest (ROI). The temperature variations may be plotted as thermographs. The thermographs may be assessed using one or more software to create a thermal profile by averaging vertical pixels.

[0080] FIG. 12 illustrates a process flow diagram depicting a method 1200 for detecting the surface tracking degradation in the high voltage polymeric insulators using the optical fluorescence fiber sensor 1102, in accordance with an embodiment of the present disclosure. The method 1200 comprises a series of operation steps indicated by blocks 1202 through 1208.

[0081] At block 1202, the optical fluorescence fiber 1104 may collect the optical emission during the one or more stages of discharge of the insulator 406.

[0082] At block 1204, the optical fluorescence fiber 1104 may generate one or more fluorescence signals based on the optical emission during the one or more stages of discharge.

[0083] At block 1206, the photomultiplier module 1106 may detect the one or more fluorescence signals from the optical fluorescence fiber 1104.

[0084] At block 1208, the control module 1108 may detect the surface tracking degradation by analyzing the one or more fluorescence signals.

[0085] In some aspects of the present disclosure, the optical fluorescence fiber 1104 may be embedded with multiple fluorescence molecules. Further, the one or more fluorescence signals may be guided through the optical fluorescence fiber 1104 by a total internal reflection.

[0086] In some aspects of the present disclosure, the optical fluorescence fiber sensor 1102 may be configured to detect one or more temporal variations of the one or more stages of discharge based on one or more signal parameters of the one or more fluorescence signals. The one or more signal parameters of the one or more fluorescence signals may comprise at least one of a rise time, a pulse width, an energy, and a peak amplitude.

[0087] FIG. 13 illustrates a waveform depicting the one or more fluorescence signals at the different stages of discharges, in accordance with an embodiment of the present disclosure.

[0088] The optical fluorescence fiber 1104 may be embedded with multiple fluorescence molecules. When the light emitted by from the insulator 406 enters the optical fluorescence fiber 1104, the multiple fluorescence molecules may become active and may generate the one or more fluorescence signals Further, the one or more fluorescence signals may be guided through the optical fluorescence fiber 1104 by a total internal reflection. The one or more fluorescence signals may travel through the optical fluorescence fiber 1104 and may emerge at the other end of the fiber 1104 which is detected by the photodetector coupled with the fiber 1104. The optical fluorescence fiber 1104 may be devoid of a numerical aperture and hence the fiber 1104 may be more suitable for real-time capturing the one or more stages of discharges of the insulator 406.

[0089] As shown in FIG. 13, the one or more temporal variations of the one or more stages of discharge were examined using optical fluorescence fiber sensor 1102. The one or more fluorescence signals exhibited distinct patterns during the IPT. As shown in FIG. 13 a, during the surface discharge stage, the response was characterized by a relatively weak signal, appearing as a small, broad peak in theinitial stage. This toned-down signal is attributed to the limited and weak nature of the discharge, resulting in a comparatively low intensity of emitted light. As shown in FIG. 13b, during the dry band formation stage, due to the elimination of moisture in the surface of the insulator 406, a flat zero intensity response was observed from the one or more fluorescence signals for a short period of time, indicating an absence of light emission. Additional peaks observed in the signal during the dry band formation are attributed to commencement of the surface discharge occurring with the introduction of the successive flow of the pollutant.

[0090] As shown in FIG. 13c, during the localized bright spot stage, the discharge further intensified, reaching close to its maximum fluorescence signal response. An apparent shift in the baseline of the signal was observed as the bright spot intensified. In the tracking stage (Figure 13d), the fluorescence intensity signal reaches to the maximum, indicating facilitation of electrical current flow through the conductive path created by the tracking. This resulted in a shorter and broader peak, accompanied by an overall brightening of the signal.

[0091] The one or more signal parameters like the rise time, the pulse width, the energy, and the peak amplitude of the one or more stages of discharges provide valuable insights for the detection of the surface tracking degradation, as illustrated in Table 1.Table 1- One or more signal parameters of the one or more fluorescence signals

[0092] From the Table 1, it may be inferred that the surface discharge stage has relatively slow rise time of 7.04 ms and the pulse width of 5.2 ms indicate a weaker and less concentrated energy release, supported by the energy value of 0.8747 J. The localized bright spot stage exhibits a faster rise time of 2.72 ms, a slightly longer pulse width of 5.55 ms, and a significantly higher energy of 7.9453 J, indicating a more intense and sustained discharge. The tracking stage demonstrates the fastest rise time of 2.4 ms, the longest pulse width of 28.842 ms, and the highest energy of 28.842 J, confirming a rapid, sustained, and intense discharge along the tracking.

[0093] FIG. 14 illustrates a scatter plot depicting t-SNE 3D visualization of features of the one or more fluorescence signals, in accordance with an embodiment of the present disclosure.

[0094] In some aspects of the present disclosure, to further analyze the one or more stages of discharge, t-t-SNE was applied to the high-dimensional fluorescence signals. Hyperparameters like perplexity and learning rate were optimized for clear separation between clusters. The 3D visualization of the features of the one or more signal parameters revealed three distinct clusters corresponding to the one or more stages of discharge, proving the potential of the optical fluorescence fiber 1104 for real-time discharge event capture and classification. The detection of the surface tracking degradation using the optical fluorescence fiber sensor 1102 demonstrates significant potential for enhancing the early detection and diagnostic capabilities in high-voltage polymeric insulators.

[0095] Referring to the technical abilities and advantageous effect of the present disclosure, operational advantages that may be provided by one or more embodiments may include providing the system and the method establish an accurate and non-intrusive method of early detection of the tracking in the high-voltage polymeric insulators, as the present disclosure focuses on the one or more stages of discharge of the insulator.

[0096] Further, the proposed system and method utilizes the OES and the optical fluorescence fiber sensor to detect the tracking, which results in significantadvancements in the early detection and characterization of the tracking of the high-voltage polymeric insulators. The proposed system and method offer high sensitivity, non-intrusive real-time monitoring, and spectral differentiation of polymeric insulators degradation stages, which are current limitations in traditional methods such as leakage current monitoring and thermal imaging. Further, the proposed system and method utilizes the t-SNE to OES spectral features and fluorescence signals has enabled the clear clustering of different stages of discharge, thereby validating the ability of these optical techniques to accurately differentiate between different stages of discharge of the insulator.

[0097] Those skilled in the art will appreciate that the methodology described herein in the present disclosure may be carried out in other specific ways than those set forth herein in the above disclosed embodiments without departing from essential characteristics and features of the present invention. The above-described embodiments are therefore to be construed in all aspects as illustrative and not restrictive.

[0098] The drawings and the forgoing description give examples of embodiments. Those skilled in the art will appreciate that one or more of the described elements may well be combined into a single functional element. Alternatively, certain elements may be split into multiple functional elements. Elements from one embodiment may be added to another embodiment. For example, orders of processes described herein may be changed and are not limited to the manner described herein. Any combination of the above features and functionalities may be used in accordance with one or more embodiments.

[0099] In the present disclosure, each of the embodiments has been described with reference to numerous specific details which may vary from embodiment to embodiment. The foregoing description of the specific embodiments disclosed herein may reveal the general nature of the embodiments herein that others may, by applying current knowledge, readily modify and / or adapt for various applications such specific embodiments without departing from the generic concept, and,therefore, such adaptations and modifications are intended to be comprehended within the meaning of the disclosed embodiments. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and is not limited in scope.

Claims

I / We claim:

1. A system (400) to detect surface tracking degradation in high voltage polymeric insulators, the system comprising:an insulator (406) coupled to a high voltage transformer (402);an Optical Emission Spectroscopy (OES) module (416) comprising:a telescope (418) configured to collect an optical emission during one or more stages of discharge of the insulator (406),a spectrometer (420) configured to acquire an emission spectrum by analyzing one or more optical characteristics of the collected optical emission during the one or more stages of discharge; andan optical fiber (422) configured to connect the telescope (418) and a spectrometer (420); anda control module (424) configured to detect surface tracking degradation by analyzing dominant peaks in the acquired emission spectrum.

2. The system as claimed in claim 1, wherein the one or more stages of discharge comprises at least one of a surface discharge, a dry band formation, a localized bright spot, and the tracking, and represents a progressive insulation degradation property of the polymeric insulators.

3. The system as claimed in claim 1, wherein the spectrometer (420) is configured to analyze the one or more optical characteristics of the optical emission over a spectral wavelength range of 197 nm to 1000 nm encompassing Ultraviolet (UV) region, visible region, and Near-Infrared (NIR) regions.

4. The system as claimed in claim 1, wherein the OES module (416) is configured to detect one or more elements in the polymeric insulators by measuring the optical emission of the insulator (406) due to excitation of atoms or ions.

5. The system as claimed in claim 1, wherein the one or more optical characteristics comprises at least one of a peak wavelength, a peak intensity, an Area Under Curve (AUC), a Full Width at Half Maximum (FWHM), and a bandgap energy (eV).

6. A method (600) for detecting surface tracking degradation in high voltage polymeric insulators, the method comprising:collecting (602), by a telescope (418) of an Optical Emission Spectroscopy (OES) module ( 16), an optical emission during one or more stages of discharge of the insulator (406);acquiring (604), by a spectrometer (420) of the OES module (416), an emission spectrum by analyzing one or more optical characteristics of the collected optical emission during the one or more stages of discharge; anddetecting (606), by a control module (424), the surface tracking degradation by analyzing dominant peaks in the acquired emission spectrum.

7. The method as claimed in claim 6, wherein the one or more stages of discharge comprises at least one of a surface discharge, a dry band formation, a localized bright spot, and the tracking, and represents a progressive insulation degradation property of the polymeric insulators.

8. The method as claimed in claim 6, further comprising:analyzing, by the spectrometer (420), the one or more optical characteristics of the optical emission over a spectral wavelength range of 197 nm to 1000 nm encompassing Ultraviolet (UV) region, visible region, and Near-Infrared (NIR) regions.

9. The method as claimed in claim 6, further comprising:detecting, by the OES module (416), one or more elements in the polymeric insulators by measuring the optical emission of the insulator (406) due to excitation of atoms or ions.

10. The method as claimed in claim 6, wherein the one or more optical characteristics comprise at least one of a peak wavelength, a peak intensity, an Area Under Curve (AUC), a Full Width at Half Maximum (FWHM), and a bandgap energy (eV).

11. A system (1100) to detect surface tracking degradation in high voltage polymeric insulators, the system comprising:an insulator (406) coupled to a high voltage transformer (402);an optical fluorescence fiber sensor (1102) comprising:an optical fluorescence fiber (1104) located alongside of the insulator (406), wherein the optical fluorescence fiber (1104) is configured to:collect an optical emission during one or more stages of discharge of the insulator (406);generate one or more fluorescence signals based on the optical emission during the one or more stages of discharge; and a photomultiplier module (1106) including a photodetector, wherein the photodetector is configured to detect the one or more fluorescence signals from the optical fluorescence fiber (1104); anda control module (1108) configured to detect the surface tracking degradation by analyzing the one or more fluorescence signals.

12. The system as claimed in claim 11, wherein the one or more stages of discharge comprises at least one of a surface discharge, a dry band formation, a localized bright spot, and the tracking, and represents a progressive insulation degradation property of the polymeric insulators.

13. The system as claimed in claim 11, wherein the optical fluorescence fiber (1104) is embedded with multiple fluorescence molecules.

14. The system as claimed in claim 11, wherein the one or more fluorescence signals are guided through the optical fluorescence fiber (1104) by total internal reflection.

15. The system as claimed in claim 11, wherein the optical fluorescence fiber sensor (1102) is configured to detect one or more temporal variations of the one or more stages of discharge based on one or more signal parameters of the one or more fluorescence signals.

16. The system as claimed in claim 15, wherein the one or more signal parameters of the one or more fluorescence signals comprise at least one of a rise time, a pulse width, an energy, and a peak amplitude.

17. A method (1200) for detecting surface tracking degradation in high voltage polymeric insulators, the method comprising:collecting (1202), by an optical fluorescence fiber (1104), an optical emission during one or more stages of discharge of the insulator (406);generating (1204), by the optical fluorescence fiber (1104), one or more fluorescence signals based on the optical emission during the one or more stages of discharge; anddetecting (1206), by a photomultiplier module (1106), the one or more fluorescence signals from the optical fluorescence fiber (1104); anddetecting (1208), by a control module (1108), the surface tracking degradation by analyzing the one or more fluorescence signals.

18. The method as claimed in claim 17, wherein the one or more stages of discharge comprises at least one of a surface discharge, a dry band formation, a localized bright spot, and the tracking, and represents a progressive insulation degradation property of the polymeric insulators.

19. The method as claimed in claim 17, wherein the optical fluorescence fiber (1104) is embedded with multiple fluorescence molecules.

20. The method as claimed in claim 17, wherein the one or more fluorescence signals are guided through the optical fluorescence fiber (1104) by total internal reflection.

21. The method as claimed in claim 17, further comprising:detecting, by the optical fluorescence fiber sensor (1102), one or more temporal variations of the one or more stages of discharge based on one or more signal parameters of the one or more fluorescence signals.

22. The method as claimed in claim 21, wherein the one or more signal parameters of the one or more fluorescence signals comprise at least one of a rise time, a pulse width, an energy, and a peak amplitude.

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