Power quality events analysis using wavelet transform

With an increasing usage of sensitive electronic equipment, power quality studies had grown to perform power quality data analysis. Wavelet transformation technique was founded to be more appropriate to analyze the various types of power quality events.This project compares the use of various types of wavelets at different scales and levels of decomposition on analyzing real recorded Power quality (PQ) events from Skudai 22kV distribution system. Voltage sag, voltage swell and transient event have been tested. PQ events data were extracted by RPM Power Analysis Softwarebased on a standard curve called as CBEMA curve. Background and indicators in CBEMA curve were studied, hence various PQ events were able to identify and analyze. This project also applied the 1-D WPT and 1-D SWTD of Matlab wavelet toolbox for further analysis the recorded PQ events. In 1-D WPT, four (4) types of wavelets with Shannon entropy based are applied and aim to determine the most appropriate mother wavelet for better compression and analyzed the recorded data of PQ event. Compression of voltage sag and swell waveforms were carried out with low energy loss capability was verified in order to preserve the original waveform of PQ event feature for further analysis. Performance of the 1-D WPT in compression on both voltage sag and swell events is compared based on Retain Energy (RE) and Number of Zeros (NZ) in percentage for all proposed wavelets at different scales and levels of decomposition. Ratio of energy loss per percentage of zero of compressed PQ events was also demonstrated. Compression using WT was also conducted for comparison.Presence of noise in the PQ events were de-noised using different mother wavelets at level 3 by varied three (3) types of noise structure available in 1-D SWTD. Effectiveness of using 1-D SWTD for analyzing transient, voltage sag and swell events with 3 different noise structures has been demonstrated by comparing the dispersion and distributionComparison of denoised waveform from WT was also demonstrated

Thunderstorm Prediction Model Using SMOTE Sampling and Machine Learning Approach

Thunderstorms are one of the most destructive phenomena worldwide and are primarily associated with lightning and heavy rain that cause human fatalities, urban floods, and crop damage. Therefore, predicting thunderstorms with reasonable accuracy is one of the crucial requirements for the planning and management of many applications, including agriculture, flood control, and air traffic control. This study extensively applied the historical lightning and meteorological data from 2011 to 2018 of the southern regions of Peninsular Malaysia to predict thunderstorm occurrence. Positive CG lightning rarely occurs compared to negative CG lightning and also due to the non-linear and complex characteristics of the thunderstorm and lightning itself, leading to an imbalance in the dataset. The resampling technique called SMOTE is introduced to overcome the imbalance of the training dataset. Then the dataset is trained and tested with five Machine Learning (ML) algorithms, including Decision Trees (DT), Adaptive Boosting (AdaBoost), Random Forest (RF), Extra Trees (ET), and Gradient Boosting (GB). The results have shown a good prediction with accuracy (74% to 95%), recall (72% to 93%), precision (76% to 97%), and F1-Score (74% to 95%) with SMOTE. The SMOTE and GB model prediction model is the best algorithm for thunderstorm prediction for this region in terms of performance metrics. In the future, the prediction results based on the lightning pattern and weather dataset will likely alert the related authorities to make an early strategy to handle the occurrence of thunderstorms

Lightning Protection of Aircraft, Power Systems and Houses Containing IT Network Electronics

Over the past decade, there has been an increasing interest in lightning and lightning protection for several reasons, including the proliferation of microelectronic equipment and IT systems in mission-critical systems as well as in everyday use in banks to homes. Lightning strikes to power lines produce large fast transient voltage and current surges which trickle down to IT systems, military command and control systems as well as to several other microelectronic equipment and control systems. Moreover, aircraft are struck by lightning when it is parked on ground, landing and taking off or in military operations where the aircraft has to keep close to the ground even when the atmosphere is electrified by thunderclouds. In this paper, we explore the protection of electronic equipment, structures and in-house systems from lightning. The paper will also explore lightning related Electrostatic Discharge (ESD) threat to aerospace vehicles and microelectronic systems. This is especially so with the increased use of non-metallic, composite material for the aircraft body. Moreover, the paper will report on the important lightning techniques used in the protection of electric power systems and houses

Lightning Protection of Aircraft, Power Systems and Houses Containing IT Network Electronics

Over the past decade, there has been an increasing interest in lightning and lightning protection for several reasons, including the proliferation of microelectronic equipment and IT systems in mission-critical systems as well as in everyday use in banks to homes. Lightning strikes to power lines produce large fast transient voltage and current surges which trickle down to IT systems, military command and control systems as well as to several other microelectronic equipment and control systems. Moreover, aircraft are struck by lightning when it is parked on ground, landing and taking off or in military operations where the aircraft has to keep close to the ground even when the atmosphere is electrified by thunderclouds. In this paper, we explore the protection of electronic equipment, structures and in-house systems from lightning. The paper will also explore lightning related Electrostatic Discharge (ESD) threat to aerospace vehicles and microelectronic systems. This is especially so with the increased use of non-metallic, composite material for the aircraft body. Moreover, the paper will report on the important lightning techniques used in the protection of electric power systems and houses

Power Transformer Fire and Explosion: Causes and Control

An increasing number of failures of power transformers over the world has led to greater interest in building up much needed expertise in electric power transformers, from its design to both preventive and prescribed maintenance. Winding failure is a frequent cause of transformer failure, bushing failure leads of fire and explosion, but it is still uncertain whether the increasing failure of transformers may be related to increasing lightning activity or increasing electric energy of the transient, surge voltages generated by lightning, especially long continuing currents and rate of rise of currents. But there are other important causes as well which need close attention, including wearing out of the contact points of tap changers in power generating and substation transformers, and poor maintenance of transformer oil. This paper seeks to review some of the well-known causes that lead to transformer fire and explosion, and highlights the important parts of the power transformer that need careful selection, installation, maintenance and condition monitoring. Moreover the containment of fires and measures that help to prevent transformer explosions in case of transformer fires are also discussed. Keywords: Embedded systems, Smart Antenna; Adaptive Array; Artificial Neural Network

Characteristics of lightning trends in Peninsular Malaysia from 2011 to 2016

Lightning is a powerful natural phenomenon, known to affect power utilities, structures, and either injured or kill a number of people and might cause large financial losses to the country both directly and indirectly. Therefore, an accurate and reliable lightning detection system is essential to enhance knowledge and awareness to forecast and identify occurrences of lightning activity. This paper focusses on the lightning trends at southern region of Peninsular Malaysia from 2011-2016 which utilized historical data from Lightning Detection System Network System, operated by TNB Research Sdn Bhd. The mean distributions, the percentage and the peak current of the lightning strikes were investigated. The relationship of the lightning trends with the main monsoon season were also evaluated. The evaluation results show that the monsoonal variation due to the shift of monsoon seasons (April-May and October-November) increased the lightning activity at the studied region. Furthermore, it is also found that a significant increase in lightning activity were observed due to the system upgrades in 2016 which reflected by the sensitivity in location accuracy and detection efficiency of the system

Replacing Ground Rod Joining Cable from Copper to Galvanized Iron

Research on electrical grounding is well established over the past 180 years but recently due to the ever increasing price of copper, theft of copper from grounding systems has become common. The cost of a lack of integrity of electrical power systems due to the stolen copper from grounding systems can be massive. Therefore it is the objective of this research is to study if the 35mm2 copper ground rod joining cable can be replaced with galvanized iron. Galvanized iron was chosen as a replacement because of its extensive used in civil engineering works which has resulted in its cheap price and easy availability. It also has sufficient electrical conductivity. The methodology of this work is to measure the ground resistance with a ground resistance meter; with copper and galvanized iron as the joining cable, over a period of eight months. The findings are that though the ground resistance using galvanized iron is higher, it is still cost effective to use more ground rods with galvanized iron joins rather than fewer ground rods with copper joints. Another unexpected finding is that beyond a certain number of joined ground rods, the reduction in ground resistance is not significant. A future work is to solve the remaining weak point in grounding systems which is the join between the joining cable and the ground rod

Detecting Sensor Coordination in a Calibrated Lightning Locating System

A number of applications use the information from lightning locating systems. Public individuals rarely have their own lightning detection networks; thus they rely on national Lightning Locating Systems (LLSs) or weather forecasters. Therefore, local LLS is useful for public to warn them as soon as the sensors detect the lightning strike. An accurate location estimation of Cloud to Ground (CG) flashes is required to be obtained by applying available detecting methods. Common lightning locating system (LLS) uses various detection techniques such as Time Difference of Arrival (TDOA), Magnetic Direction Finding (MDF) and interferometry. However, these techniques have their own positive points and disadvantages. Low accuracy, high cost, time synchronization problems are several of these weaknesses. Therefore, calibrating the lightning detecting sensors has direct impact on the accuracy of a LLS. In this study, a calibrated LLS including the cross loop antennas, parallel plate antennas and GPS cards with data loggers have been installed at each of the three stations to capture the waveforms and to save the time stamps of incoming signals for further analyses. The captured waveforms of a real lightning discharge were investigated to measure the accuracy of a calibrated system

Power Quality Improvement on Wind Energy System by Using STATCOM

Wind energy known as a cheap, clean and uncontrolled resource and becomes an important green electricity source. However, installation of wind system into an electric grid introduces the Power Quality (PQ) phenomenon. These poses great challenges leads to various control schemes and new techniques to mitigate the PQ events. This paper described the improvement of PQ events in a grid connected wind energy system by using Static Compensator (STATCOM) with a Battery Energy Storage System (BESS) at the Point of Common Coupling (PCC). The performance of the proposed wind energy system is simulated via MATLAB/SIMULINK in power system block set