Lightning Location and Mapping System Using Time Difference of Arrival (TDoA) Technique

Lightning strike is a dangerous natural phenomenon that can cause various problems. Telecommunication subscriber lines (TSLs) and electrical power lines are two systems that are almost always affected by nearby lightning strikes. Voltages in the telecommunication subscriber line (TSL) do get induced by nearby lightning strikes. The induced voltage can be carefully measured and lightning parameters such as the lightning current wave shape, lightning peak current and strike locations be reproduced. Better designs of lightning protection systems can be realised if data on lightning strike distribution in a given region is known. Commercial lightning mapping or locating systems are based on several technologies (Araujo, 2001; Kenneth, 2003). The two most popular methods are those based on the Time of Arrival (ToA) and the Directional Finder (DF) principles. An example of the lightning locating system (LLS) based on the ToA method is the country- wide LLS owned by the Malaysian national power company (TNB). The system is capable of determining the coordinates of the cloud-to-ground lightning strikes within 500m accuracy. However, for a localised distribution of lightning, say within 1 square km area, this accuracy is too large for the data to be meaningful

Condition Monitoring of Zinc Oxide Surge Arresters

Over voltages in power system may occur due to lightning, fault or switching operation. These overvoltages could reach dangerous amplitudes for power system apparatus. To protect the system electrical equipment and to guarantee an economic and reliable operation, surge arresters are applied in almost all types of electrical power network. Gapless zinc oxide (ZnO) surge arresters are widely used. The surge arresters are usually connected between the phase and ground terminals. They limit the voltage level in equipments such as transformers below the withstand voltage level

SOLID WASTE AS A RENEWABLE FEEDSTOCK: A REVIEW

ABSTRACT This paper reviews the effect of waste to energy in terms of environmental, energy production, as a tool for diverting waste from landfill and the suitability of adopting energy from solid waste as a renewable energy based on the environment protection authority's classification of waste into biogenic and non-biogenic elements. Lifecycle assessment (LCA) of various waste management methods in terms of environmental and sustainability influences favors waste to energy as the preferred method of waste management. Analysis shows that for every ton of solid waste converted to energy about 376 grams of emission is fossil related compared to 1,833 grams for conventional fuel, like coal. Although solid waste has a lower calorific value as compared to conventional means of energy generation with about one-third of the value for coal, it can generate 600 kWh, all from renewable components, thereby saving lots of fossil fuel from being burned to generate this energy. A case study of solid waste generated at Universiti Teknologi Malaysia (UTM) is also reported in order to show the true status of solid waste as renewable energy

A synopsis on the effects of anthropogenic greenhouse gases emissions from power generation and energy consumption

Despite the looming difficult energy context in the majority of countries in the world, global change in environmental dignity resulting from power generation and energy consumption scenario is rapidly becoming a globally disturbing phenomenon. Stakeholders and environmental activists alike have been clamouring for adoption of reduction procedures using sustainable means because ignominious environmental practices have associated disastrous consequences. Increasing essential strategies are needed to fortify the pursuit for the reduction in the emissions from power generation and energy consumption. Therefore, this article presents an overview of the effects of anthropogenic energy generation and consumption practices capable of ejecting emissions of greenhouse gases into the atmosphere. It also endeavors to identify some greenhouse gas emission reduction and control measures

Atmospheric electric field data logger system

Weather can be unpredictable as there are a lot of uncertainties in predicting thunderstorms. Most of our navigation systems, including those on air, land and water, as well as broadcasting systems, are directly affected by the weather on a daily basis. The inconsistent and unreliable nature of storms brings out the importance of research in atmospheric electric field data logging systems. This paper presents a study to develop a virtual instrument with the capability to analyse and store the magnitude (data) of atmospheric electric fields. The study was carried out using a LabVIEW virtual instrument and tested using data acquisition (DAQ) and a function generator. The developed virtual instrument consists of waveform chart, tabulated data, and histogram for real time observation. Moreover, it has feature to save and recall data for further analysi

Evaluation of 11kv XLPE Cable

Underground power cables constitute a bulk part of power systems network. Most of these power system equipments have been in service for decades, thus making their insulation liable to deterioration (ageing) as a result of operational and environmental stresses. For the past decades, the Recovery Voltage Method (RVM) has been widely used to evaluate ageing in oil-paper insulated cables. This work presents the evaluation of ageing in 11kV XLPE cable using the RVM. Statistical Analysis was employed to predict the progress of ageing. Accelerated ageing using AC and impulse voltages was performed on new XLPE cable samples. Within the period of ageing, the state of insulation was investigated and assessed using the RVM. Regression Analysis was used to predict the progress of ageing in cables, with the CTC (central time constant) being the response variable. However due to technical problems encountered in the course of this study, synthetic data were used to model the regression equation. The result of the diagnosis using the RVM showed that the aged XLPE cables had higher values of Urmax (maximum return voltage) than the unaged ones, indicating the samples have undergone thermal ageing. An R2 of 0.981 was obtained from the regression equation, implying that the predicted values of the CTC were 98.1% close to the observed values. The RVM technique, which was initially proposed for diagnosis of oil-paper insulation systems, was found to be able to detect ageing in XLPE cables, and thus insulation diagnosis using this technique could be extended to extruded-insulated cable systems. The Regression Analysis, a tool for forecasting and prediction, can be used to predict the progress of insulation deterioration and agein

Odd harmonics and third to fifth harmonic ratios of leakage currents as diagnostic tools to study the ageing of glass insulators

This paper reports an investigation into the leakage current harmonic components of 45 units of glass insulator samples. The insulator units comprise 5 groups of insulators: new insulators and naturally field-aged insulators with different ageing periods->30, 20, 15, and <10 years from a 132 kV transmission line. Experiments were conducted at different electrical stresses (0.17, 0.24, and 0.34 kV/cm) and salt-fog conductivities (900 and 1500 µS/cm). The results suggest that the insulator samples¿ leakage current (LC) waveform and the total harmonic distortion (THD) correspond well with degree of ageing. Fast Fourier Transform (FFT) analysis performed on the stored waveforms showed a strong correlation between the ratio of the third to fifth harmonic amplitudes with the degree of ageing and in-service period of the naturally field-aged insulators. Furthermore, this investigation revealed a pattern between the groups of insulator samples in respect to their ageing. These findings were further validated with traditional Dielectric Dissipation Factor tests carried out on the insulators, and the results also correlated well with the samples¿ degree of ageing as well as service period. In addition, neural networks were trained to recognize the insulator samples¿ degree of ageing. This study found that, alternative to the diagnosis of insulator ageing through the measurement of loss angles or tangent delta, LC harmonics can be used as diagnostic tools and for the on-line monitoring of in-service aged transmission line ceramic glass insulators based on odd harmonics and third to fifth harmonic ratios

Furan analysis on power transformers in Malaysia: a field investigation

The insulating materials (oil and cellulose paper) of power transformers undergo ageing during service. Thus condition monitoring of power transformers in service is very important. An established chemical test carried out on the transformer oil to determine the level of paper insulation deterioration in power transformers is the Furan Analysis. Numerous studies have been carried out to investigate transformer ageing in the laboratory, however, field investigations on full-scale or commercial power transformers using Furan Analysis are lacking. This paper reports an investigation on the concentration of 2-Furfuradehyde in oil samples collected from 414 power transformers of Tenaga Nasional Berhad (Malaysia national power company) transmission and distribution system. Statistical analysis of the Furfural data showed a trend in the furfural concentrations (FC) of the power transformers. Temporal variation showed older transformers had higher FC. Further analysis on case by case basis on six transformers revealed that FC correlated well with the level of transformer insulation deterioration and operating conditions. Frequency Dielectric Spectroscopy test carried out on some of the power transformers corroborated the above findings

Renewable power generation opportunity from municipal solid waste: a case study of Lagos Metropolis (Nigeria)

Renewable power generation is increasingly becoming a well-known phenomenon in our modern society. Various research efforts have been rationalized to prove the benefits that could be derived from the utilization of renewable energy resources for electricity. Though, environmental benefits have been the major focal advantage but in the case of municipal solid waste (MSW), socio-economic impact on the society is possible in the form of saving in land allocation for waste management and income generation. Therefore, this study discusses the concept of waste-to-energy (WTE) management in Lagos metropolis as a case study. Lagos state has 20 administrative Local Government Areas with 16 of them forming the Lagos metropolis. The study also significantly accesssed the potential of MSW for power generation considering the route of thermo-chemical conversion as an alternative measure to landfilling and open dumping of waste commonly practice in the metropolis. It was found that approximately 442MWe is possible to be achieved using a population benchmark of over 16 million recorded in the metropolis in 2006.Three major techniques for energy generation from MSW are also discussed.Finally the study was concluded on possible investment issues to enhance the resources utilization for energy purpose