Voltage Partial Discharge Research Articles

Using partial discharge data to identify highly sensitive electrochemical parameters of aged lithium-ion batteries

Highly sensitive (HS) electrochemical parameters can serve as battery aging indicators, deserving thorough examination. To identify these parameters and determine their cycle evolution across a wide range of battery state of health, this study conducts a three-stage analysis. First, after a detailed evaluation, a global sensitivity analysis is performed to evaluate the sensitivity values of ten selected parameters across five intervals of discharge voltage curves simulated through the Doyle-Fuller-Newman theory. Such analysis facilitates the classification of these parameters into HS and low sensitive (LS) groups. Next, a deep learning (DL) model is developed for parameter identification, employing as minimal data as possible, specifically only partial discharge curves and their corresponding first-order derivatives, as inputs, while the electrochemical parameters are generated as outputs. It is found that utilizing the model built with the HS parameters achieves a remarkably low mean absolute percentage error (MAPE) of 0.25 % for output prediction. On the contrary, adopting the LS parameters yields a MAPE of 13.30 %, highlighting the significant impact of parameter sensitivity on the model outputs. Lastly, the well-trained DL model is directly applied to identify the five HS parameters pertaining to real-world commercial batteries, whose state of health spans approximately from 97 % down to 55 %. With the experimentally recorded partial discharge voltage data, the model generates the cycle evolutions of the HS parameters, revealing a noticeable decrease in their values ranging from 12 % to 40 % with aging.

Simulation Analysis of Corona Pulse Propagation along the Line Based on an Actual Transmission Line

Abstract In the partial discharge test of the shunt reactor of the ultra-high voltage transmission line, the corona discharge caused by high voltage interferes with the test. To further study the propagation rules of the corona pulse on the line side in the transmission line during the ultra-high voltage partial discharge test, based on the parameters of an actual transmission line, the ATP-EMTP electromagnetic simulation software was used for modeling. The propagation rules of corona pulses in the transmission line were analyzed in detail through the simulation model. As the propagation distance increases, different frequency components show different degrees of attenuation. The higher the frequency is, the faster it attenuates.

A partial discharge detection system based on improved STMS fiber UV sensor

The occurrence of partial discharge in high-voltage transmission equipment can lead to insulation breakdown, emphasizing the critical need for early fault detection. Traditional sensors are highly vulnerable to electromagnetic interference, which significantly impacts the accuracy and reliability of the obtained results. This paper presents an all-fiber ultraviolet (UV) sensor based on the STMS structure coated with zinc oxide (ZnO) composite graphene, realizing partial discharge detection based on optical theory. Firstly, using first principles calculation method, we conducted a comparative study on the ultraviolet-sensitive materials ZnO and ZnO composite graphene. The results demonstrate that the composite material exhibits optical response characteristics that are more suitable for partial discharge detection. Subsequently, sensitive materials with different surface morphology were prepared by hydrothermal method. These materials were uniformly coated on the waist cone region of the STMS optical fiber sensing unit using surface functionalization techniques. The UV test results showed that the flower-shaped ZnO composite graphene coated STMS optical fiber sensing has a higher sensitivity of 857.41 pm/nW cm−2, reaching 1.62 times that of rod-shaped sensitive materials. Finally, the test results of the partial discharge environment indicated that the sensor showed a good linear response when the partial discharge voltage was above 21.55 kV. The UV optical fiber sensor demonstrates promising potential for applications in the field of partial discharge detection.

Enhancing real-time degradation prediction of lithium-ion battery: A digital twin framework with CNN-LSTM-attention model

Lithium-ion batteries (LIBs) have gained widespread usage in electric vehicles (EVs) due to their high energy density, long cycle life, and environmental friendliness. However, as LIBs undergo repeated charging and discharging cycles, they experience performance degradation. When the rated capacity of LIBs drops to approximately 80 %, retirement becomes necessary. Therefore, accurately determining real-time battery degradation is of paramount importance. This study presents a digital twin framework for analyzing and predicting LIB degradation performance. Within this framework, the back propagation neural network (BPNN) is employed to predict and complete the partial discharge voltage curve of the actual battery cycle. Building upon this, in conjunction with the battery's state of charge (SOC), the convolutional neural networks-long short term memory-attention (CNN-LSTM-Attention) model is utilized to real-time forecast the maximum available capacity of LIBs and reveal the battery's degradation state. Experimental results demonstrate a 99.6 % accuracy in completing the partial discharge voltage. Moreover, the prediction accuracy for maximum available capacity surpasses 99 % with a maximum error of less than 3 mAh. Thus, this research substantiates the efficacy and practical applicability of the proposed approach.

Use of Plat-Bar Electrode Media to Detect Partial Discharge in Epoxy Resin Materials on PCB Surfaces

The electric power system must have a protection system with reliable electric power isolation, so that the supply of electrical energy works properly and optimally. There are several kinds of disturbances in the electric power distribution system, one of which is a partial discharge. This study aims to investigate the effect of plate-rod electrodes on partial discharge, partial discharge voltage limits in solid insulation, and the characteristics of partial discharge in electrode media, and waveforms in partial discharge detection sensors. After conducting research, it was found that in the plate-rod type electrode media, the PDIV voltage appeared earlier than the plate-plate electrode media due to the cross-sectional area of the electrode media. And the limit of the pre-discharge voltage of PCB type solid insulation on the plate-bar electrodes is at a voltage of 1.3 kV. Several indicators to determine the characteristics of the partial discharge are background noise off (BGN off), background noise on (BGN on), partial discharge inception voltage (PDIV), and partial discharge voltage. After being examined, the value of each partial discharge detection voltage was obtained at negative and positive polarity voltages on the electrode plates and plate needles respectively 2.85 kV, 2.95 kV and 1.32 kV, 1.57 kV.

A Contemporary Review of High Voltage Partial Discharge Detection and Recognition Techniques

This review article provides a summary of the most advanced approaches and advancements in the detection and recognition of high voltage partial discharge (PD). It discusses numerous detecting technologies, such as electrical, acoustic, and optical approaches, as well as their merits and disadvantages. It also discusses current developments in signal processing and pattern recognition algorithms used for PD detection and classification. Lastly, the study covers the challenges and limitations in high voltage PD detection and identification studies, as well as potential future solutions.

THE IMPACT OF IEC60076-3 ON SOLID-STATE TRANSFORMER DESIGN

This paper is an incremental contribution to SST prototype designs and written in the context of SST application in the Dutch electricity grid. The grid is faced with, amongst others, increased penetration of Photo-voltaic (PV) energy sources and Electric Vehicles (EVs). Distribution System Operators (DSOs) are expecting increased fluctuations of their grid voltages. These fluctuations present risks to connected equipment and the Solid-State Transformer (SST) is considered an important solution. While SST prototypes have previously been built, the consequences of the IEC60076-3(2013) test standard for transformers have not been taken into account when applied to SST designs. Specifically, the induced voltage withstand test (IVW), the induced voltage partial discharge (IVPD), and applied voltage (AV) tests. These tests are investigated and their impact is assessed through designing and building an SST prototype. Due to the different breakdown mechanisms of transformers and SSTs, the IVW & IVPD are demonstrated to result in a requirement to over-dimension the SSTs input voltage capability by a factor of two and the AV impacts all aspects of the SST with regards to galvanic isolation. Particularly affected are the dual active bridge (DAB) transformers and the necessary electric field shaping of the medium voltage (MV) assembly.

Calibrating Method of Aging Degree of Silicone Rubber for Composite Insulator in the Power Grid Operation

There are many factors that cause the aging of composite insulators, and the aging of the insulators will cause greater harm to the operation of the power grid and the quality of power consumption of users. This paper analyzes the mechanism of insulator aging caused by different factors, and uses optical microscope to study the microscopic morphology of insulators to determine the degree of insulator aging. The board-to-board partial discharge experimental device is used to further verify the accuracy of the calibration, and the partial discharge voltage is used as the characteristic quantity to judge the degree of aging. The results show that the partial discharge voltage changes with the aging degree of composite insulators, and presents a certain rule. This research provides a favorable reference for the aging calibration method of composite insulators.

Analysis of the Influence of Silicone Rubber Aging on the Transmission Parameters of Terahertz Waves

In this study, a method for testing the aging of silicone rubber insulators using terahertz waves in the 0.17–0.22 THz frequency band is proposed, aiming at the problem of online non-destructive testing of the aging degree of composite insulators. The relationship between the aging degree of silicone rubber composite insulators and the relative dielectric constant was studied through first-principles calculations and molecular chain scission models. In addition, the electromagnetic model of the terahertz signal incident on the silicon rubber sheet was simulated and the relationship between the aging degree of the silicon rubber and the terahertz input return loss was obtained. Eleven insulator samples with different degrees of aging were selected. In these samples, the degree of aging was calibrated according to the degree of surface deterioration and the average partial discharge voltage. The terahertz return loss measurement experiment was performed after that. Finally, the results of experiment and calculation simulation were compared and the reliability of the relationship between the aging degree of the silicone rubber insulator and the terahertz input return loss was verified.

Measuring Setup for Investigation and Visualization of the Percolation Phenomenon in Non-Оrdered Models of Metal-Dielectric Nanocomposites

The study uses the phenomenon of high voltage partial discharge to investigate the phenomenon of percolation and visualisation of the percolation channel. The phenomenon of partial discharges is very similar to the quantum tunneling phenomenon observed in metal-dielectric nanocomposites. In both cases the flow of alternating current occurs in the absence of direct contact between the metallic phase particles.A measuring stand was developed and constructed to test models of metal dielectric nanocomposites using high voltage partial discharge. The stand consists of a 110 kV high voltage transformer, a voltage regulator protecting the constant rate of high voltage rise, a measuring system consisting of a measuring probe, voltmeters and a computer. The communication between the measuring probe and the voltmeter was made in digital technology with the use of fiber optic technology, which allowed the meter to communicate with the computer without any errors and eliminated the interference caused by a strong electromagnetic field resulting from the use of high voltage.Systems modelling metal-dielectric composites were built, consisting of metallic elements in the form of disks, randomly distributed on the surface of the dielectric matrix. The number of disks was increased in series of 40 in each. The maximum number of disks was 1520. The dependence was determined of one of the important parameters characterising an partial discharge, i. e. the initial voltage, at which an electric current starts to flow between electrodes, on the concentration of the metallic phase. On the basis of these results, a percolation threshold was established for a matrix with a random distribution of metallic phase elements, the value of which is about 50 %. Films and pictures of partial discharges with visible percolation channels were taken with the camera with which the stand was equipped.

Distributed Partial Discharge Detection Technology for High Voltage Cable Based on Ac Withstand Voltage

with the Development of Urbanization, It is More and More Urgent to Improve the Reliability and Stability of Power Supply. Due to the Consideration of Municipal Planning, Environment, Personal Safety and Other Factors, the Utilization Rate of Power Cables in Urban High-Voltage Transmission Channels Has Increased Dramatically. Accidents Such as Fire, Large-Area Power Failure and So on, Which Are Caused by Internal Insulation Defects of Cables, Defects in Joint Position Fabrication and Installation Process, Occur from Time to Time. This Paper Studies the Detection Method of Potential Insulation Defects in the Cable Interior and Joint Position Based on the Ac Withstand Voltage Partial Discharge Detection Technology, and Designs a Set of Distributed Partial Discharge Test System Based on the High Frequency Pulse Method to Detect the Interior, Middle Indirect Head and Terminal Head of the Cable. in the Field, the Distributed Pd Detection Technology Based on Ac Withstand Voltage Designed in This Paper Can Effectively Detect the Internal and Joint Insulation Defects of Power Cables, and Realize Fault Location, Which Has the Value of Practical Application and Promotion.

The effect of gamma radiation on the stator insulation of rotating electrical machines

ABSTRACTThe paper examines the influence of γ radiation on the stability of the insulation characteristics of the stator winding of rotating electrical machines. The tested insulation characteristics are loss tangent angle, resistance, polarization factor, threshold voltage of partial discharge, breakdown voltage, coefficient of proportionality and lifetime exponent. The radiation dose was used as the γ radiation parameter. Different winding areas have been specifically tested in which a different impact is expected on technological winding production process. Tests were performed on a representative statistical sample under well-controlled laboratory conditions. The combined measurement uncertainty of the experimental procedure was about 5%.

Experimental research on insulation properties of C 6 F 12 O/N 2 and C 6 F 12 O/CO 2 gas mixtures

This study investigates the insulation performance of the new environmental friendly insulation gas C6F12O mixed with N2 and CO2 under the AC frequency voltage under 0.10–0.30 MPa. Firstly, the mixing ratio of C6F12O in the mixed gas is discussed by the gas phase state equation. The breakdown voltage of C6F12O gas mixtures under quasi-uniform electric field and the initial voltage of partial discharge in the highly non-uniform field are measured by the experimental method, and the insulation characteristics of SF6 gas mixtures are compared. The self-recovery performance of the gas mixture is analysed as well. Experimental results show that the mixing ratio of C6F12O is lower than 7% under 0.10 MPa, such that the operation requirements of the equipment can be satisfied. The breakdown voltage of 3% C6F12O gas mixtures is the same as that of 10% SF6 gas mixtures. The partial discharge inception voltage of 6% C6F12O gas mixtures is close to that of 10% SF6 gas mixtures. After 100 times of breakdown, the breakdown voltage of C6F12O gas mixtures does not decrease. Compared with N2, the breakdown voltage of C6F12O mixed with CO2 shows a more dispersive trend.

친환경 가스 중 전극과 고체절연체의 불량접촉에 관한 절연진단연구

This paper presents the characteristics of partial discharge and radiated electromagnetic waves in the existence of a poor contact for the insulation diagnosis of eco-friendly power equipment. AC surface discharge experiment was conducted to simulate the poor contact between a hive voltage electrode (anode) and a solid insulator in NSUB2/SUB/OSUB2/SUB mixture gas under a non-uniform field. The partial discharge voltage to be measured at 0.3MPa increased with the increase of the poor contact gap and was saturated with the gap. In addition to the partial discharge characteristics, it was verified that the defect of the poor contact can be diagnosed using the radiated electromagnetic waves due to the partial discharge, which measured by a biconical EMC antenna and a spectrum analyzer.

Electrical and Thermal Characterization of Organic Varnish Filled with ZrO2Nano Filler Used in Electrical Machines

In the last decade it has been witnessed significant developments in the area of nano particles and nano scale fillers on electrical, thermal, and mechanical properties of polymeric materials such as resins, varnishes, enamel and bakelites. The electric and thermal properties were more important in the electrical equipments for both steady state and transient state conditions. This paper deals with the characterization of the electric and thermal properties of the pure varnish and zirconia (ZrO2) filler mixed varnish. The electric properties such as dielectric loss (tan δ), dielectric constant (e), dielectric strength and partial discharge voltage were analyzed and detailed for different samples. It was observed that zirconia nano filler mixed varnish has the superior dielectric and thermal properties when compared to those of standard varnish. It has shown that at power frequency the 1wt% nano composite sample has the higher permittivity value when compared to other samples. It has been examined that the 1wt% sample was having higher inception and extinction voltages when compared to other samples. It has been observed that 1wt% sample has higher dielectric strength when compared with other samples. There has been an improvement of thermal property by adding few weight percent of zirconia nano fillers. There was not much variation in glass transition among the nano mixed composites. The weight loss was improved at 1wt% of the zirconia nano fillers.

Prediction of residual breakdown electrical field strength of epoxy-mica paper insulation systems for the stator winding of large generators

A method of predicting the residual breakdown electrical field strength of an epoxy-mica paper insulation system is described. This method was developed by using data on service–aged stator bars from generators as well as accelerated aging model bars. Thermal aging, mechanical aging, and combined thermal and mechanical aging were done individually as accelerated aging. The partial discharge characteristics, dissipation factor, and breakdown voltage were measured on the model bars and service–aged bars from generators. From these results, the residual breakdown electrical field strength was predicted based on the partial discharge characteristics and dissipation factor. First, the dominant type of deterioration (thermal or mechanical aging) on a bar’s insulation was determined by the pattern of voltage–partial discharge magnitude characteristics. Then the residual breakdown electrical field strength was predicted by using a predicting equation for both thermal and mechanical aging. Each predicting equation uses dissipation factor tip-up (i.e. difference in dissipation factor values between 2 kV and rated voltage) and partial discharge inception electrical field strength. The accuracy of this method was confirmed using data measured on 112 service-aged stator bars from generators and 10 accelerated aged model bars. The 95% confidence interval level included 94% of the measured residual breakdown electrical field strength values. This result shows that the method enables precise predictions of the residual breakdown electrical field strength of an epoxy-mica paper insulation system.

부분 방전에 의한 실리콘 케이블의 열화 특성에 관한 연구

In this study, the characteristics of partial discharge was measured for the four core silicone cable (0.6/1.0 kV, <TEX>$1.0SQ{\times}4C$</TEX>) with insulated part of 15 cm and conductor of 1cm. The following results have been confirmed as a result of this study. When the first line of cable is connected to the positive electrode and the second, third line of cable is connected to the negative electrode, it found that the inception voltage and extinction voltage decreased with increasing the line of negative electrode, and the partial discharge charge quantity(Q) increases, while the number of discharge occurrence has decreased. The inception voltage and extinction voltage of partial discharge has decreased with increasing the degradation rate in the 33%, 67%, 100%. Also, it confirmed that the partial discharge charge quantity(Q) and the number of discharge occurrence has decreased.

Study of Surface Flashover and Breakdown Characteristics in Liquid Nitrogen for SFCL Application

With the rapid development of commercial use of superconducting fault current limiters (SFCLs), higher and higher voltage use is being taken into consideration. Insulation property is crucial and limits the development at high voltage level. G10, as an excellent insulation material for cryogenic use, can be applied in high voltage SFCL module. Based on the fundamental design of SFCL module in Shanghai Jiao Tong University, flashover characteristics of G10 in LN2 are researched to design the SFCL module. In addition, ac breakdown strength of SFCL module terminals is investigated to design module distance to ensure insulation safety and do not make SFCL too large. Simulations are conducted to study the theoretical electric field distribution. Partial discharge voltage and ac surface flashover breakdown voltage of different electrodes are measured. SFCL module terminal electrodes and triangle-plane electrodes are applied. How the surface flashover breakdown strength would be affected is studied by changing the electrode gap. Breakdown strength property of SFCL module terminal is also studied by altering the distance of electrodes. The experiment results show that gas gap and surface length do influence the partial discharge charge and flashover breakdown voltage. Bubbles also affect breakdown strength between terminals. These results are conducive to design SFCL module.

2[MVA] 몰드변압기 절연물내 기포 영향을 고려한 전계해석

This paper presents the electric field analysis for 2[MVA] mold transformer using finite element method. The electric field was calculated for the voltage applied to the mold transformer without voids in the insulating material. Then, it was analysed the maximum electric field when the voids was in the insulating materials. And the starting voltage of partial discharge was predicted due to the voids. The effects of voids in epoxy resin on the electric field were investigated for different sizes, shapes, positions and arrangements of voids.

Partial discharge pulse pattern recognition using hidden Markov models

An approach for the classification of cavity sizes based on their maximum charge transfer characteristics, applied voltage partial discharge pattern using Hidden Markov Models, is described. In these models, the partial discharge patterns for different cavity sizes are represented by a sequence of events rather than by the actual curves. In the training phase, each cavity size represents a unique class, which emits its own eigen sequence. Vector Quantization is deployed to assign labels for this particular sequence of events. A Hidden Markov Model is trained for each class, using a set of training patterns consisting of the labels produced by Vector Quantization. During testing, the sequence of events to be recognized is quantized and then matched against all the developed models. The best-matched model pinpoints the cavity size class. Experimental results demonstrate the remarkable capability of the proposed algorithm.