Examination on the Denoising Methods for Electrical and Acoustic Emission Partial Discharge Signals in Oil

Partial discharge (PD) measurements either through electrical or acoustic emission approaches can be subjected to noises that arise from different sources. In this study, the examination on the denoising methods for electrical and acoustic emission PD signal is carried out. The PD was produced through needle-plane electrodes configuration. Once the voltage reached to 30 kV, the electrical and acoustic emission PD signals were recorded and additive white Gaussian noise (AWGN) was introduced. These signals were then denoised using moving average (MA), finite impulse response (FIR) low/high-pass filters, and discrete wavelet transform (DWT) methods. The denoising methods were evaluated through ratio to noise level (RNL), normalized root mean square error (NRMSE) and normalized correlation coefficient (NCC). In addition, the computation times for all denoising methods were also recorded. Based on RNL, NRMSE and NCC indexes, the performances of the denoising methods were analyzed through normalization based on the coefficient of variation (). Based on the current study, it is found that DWT performs well to denoise the electrical PD signal based on the RNL and NRMSE index while MA has a good denoising NCC and computation time index for acoustic emission PD signal

Investigation of Static Voltage Accumulation on Wind Turbine Blade in Atmospheric Wind speed Humidity and Temperature

Wind turbines are one of renewable energy sources. Wind turbines installed at wild open area such offshore, mountains and deserts are filled with air particles and flow of wind speed. During the wind flow throughout the wind turbines which rotates the turbine blades, there is friction between the air particles and the blade surface that leads the static voltage to accumulate on the blade surface causing upward streamers. Using fiberglass reinforced plastic (FRP) wind turbine blades by simulation and experimental method. The charged particle tracing with electrostatics and laminar flow with time-dependent used to determine the value of static voltage accumulation. Static voltage accumulation is influenced by various factors such as wind speed (1, 5, and 7 m/s), humidity (20, 50, and 70 %RH) and temperature (28, 35, and 48 oC) had tested and analyzed. Furthermore, the result obtained using the Finite Element Method (FEM) has shown a good agreement with the experimental result. It was observed that high flow velocity has a great tendency to charge the blade surface with 36.70%higher from 1 m/s to 7 m/s. Low relative air humidity increases the risk of static electricity 221.6 V at the of side of the blade when humidity is 20%. Moreover, increasing the air temperature from 28 to 48 degrees Celsius increases the voltage by 20%. Therefore, determining the need for statice voltages generated in the blade surface and the risk related to upward streamers is obliged to be evaluated as it is the essential ways in adopting the correct protection systems

Inactivation of mucose on bread by using plasma jet

This paper presents the application of cold plasma technology on bread. Plasma is a fourth state of matter apart from solid liquid and gas states. It possesses the same amount of negative and positive ions that are produced from the gas molecule that goes through the electrical breakdown process. Plasma can be produced by injecting high voltage through an electrode. This project aims to develop a plasma jet system that will be able to produce cold plasma with the help of argon as the working gas. Due to its multifunction purpose, cold plasma can be used in many different fields such as biomedical, textile manufacturing, surface modification, food packaging, and many more. In this study, plasma generated with higher voltage may reduce the occupation of mucose on the bread as compares to the control

Electrical tree inception voltage and propagation in XLPE containing silica nanofiller

This paper presents the tree inception voltage and electrical tree propagation in XLPE containing silica nanofiller. The concentration of silica nanofillers in XLPE was 0 wt%, 0.5 wt%, 1.0 wt%, 1.5 wt% and 1.75 wt%. The needle plate electrodes were used to analyzed the tree inception voltage and electrical treeing propagation. The structure and the propagation length of electrical tree growth were analyzed after 20 min of tree inception voltage. The result of tree inception voltage and the electrical tree propagation in XLPE containing silica nanofiller was compared with pure XLPE composite. The silica nanofiller with the concentration of 1.5 wt% revealed the higher TIV and slower propagation of electrical tree in the XLPE nanocomposite

Effect of silica nanofiller in cross-linked polyethylene as electrical tree growth inhibitor

One of the main phenomena that contributes to the non-success of cable insulation made of cross-linked polyethylene (XLPE) is electrical treeing. To improve the XPLE cable insulation, the use of nanofiller has been introduced. Adding the nanofiller in the based composite offers better cable lifetime and resistance to deal with the cable failure. One of the potential nanofillers that can increase the insulation performance of XLPE cable is silica nanofiller. To this extent, the studies on silica nanofiller in XLPE are focusing on the impulse breakdown strength, dielectric loss, permittivity, space charge, alternating current (AC), and partial discharge. The studies reveal that the dielectric properties of the XLPE nanocomposite have significant improvement. Therefore, this work investigates the effect of various concentrations of silica nanofiller in XLPE composite as electrical tree inhibitor. The concentrations of silica nanofiller in XLPE were 0.25 wt%, 0.5 wt%, 0.75 wt%, 1.0 wt%, 1.25 wt%, 1.5 wt%, and 1.75 wt%. The silica nanofillers have 96%-99% purity, 20-30 nm sizes and the shapes are spherical. As a result, the XLPE composite containing 1.5 wt% silica nanofiller demonstrate higher tree inception voltage and detaining the tree propagation speed, which could be considered as an inhibitor medium of electrical tree growt

Performance Evaluation of Edge-Based Segmentation Methods for Electrical Tree Image Analysis in High-Voltage Experiments

This research evaluates the performance of edge-based segmentation methods in analysing two-dimensional (2D) electrical tree images obtained during high-voltage (HV) electrical tree experiments. Non-uniform illumination in 2D optical images poses challenges in accurately extracting and measuring the original treeing image. Edge segmentation emerges as a promising solution to precisely distinguish tree structures from the insulation background within the image. Cross-linked polyethylene (XLPE) samples were subjected to HV stress for real-time propagation observation, followed by extraction and segmentation of treeing images using edge-based operators. The findings emphasize the superiority of the Roberts edge operator in accurately detecting electrical trees, showcasing the highest average accuracy of 97.01% and 99.58% specificity, while also demonstrating relatively high sensitivity. Moreover, the Roberts method provide much precisely measures the propagation length and width than conventional measurement method, closely approximating the actual tree measurements. This research emphasizes the significance of accurate segmentation for investigating electrical tree propagation in XLPE materials and provides recommendations for future research, especially in HV XLPE cable manufacturing

診断技術開発の基礎としての環境調和型ガス絶縁媒体の部分放電特性および分解ガス分析の研究

九州工業大学博士学位論文 学位記番号: 工博甲第260号 学位授与年月日: 平成20年3月25日Chapter 1 Introduction|Chapter 2 Experimental setup and method|Chapter 3 Discharge properties and emitted electromagnetic wave spectrum in low vacuum region of vacuum interrupter|Chapter 4 Partial discharge properties and determination of gas pressure in vacuum interrupter based on partial discharge|Chapter 5 AC sparkover voltage properties and gas decomposition by-product analysis of CF3I under non-uniform electric field| configuration|Chapter 6 Summary|Appendix|Acknowledgment|List of publications九州工業大学平成19年

診断技術開発の基礎としての環境調和型ガス絶縁媒体の部分放電特性及び分解ガス分析の研究

九州工業大学博士学位論文（要旨） 学位記番号:工博甲第260号 学位授与年月日:平成20年3月25