Wavelet transforms : practical applications in power systems.

An application of wavelet analysis to power system transient generated signals is presented in this paper. With the time-frequency localisation characteristics embedded in wavelets, the time and frequency information of a waveform can be presented as a visualised scheme. This feature is very important for non-stationary signals analysis such as the ones generated from power system disturbances. Unlike the Fourier transform, the wavelet transform approach is more efficient in monitoring fault signals as time varies. For time intervals where the function changes rapidly, this method can zoom in on the area of interest for better visualisation of signal characteristic

Teaching power system analysis courses using MATPOWER

One of the major constraints faced in the teaching of power system analysis courses has been non-availability of practical power system for demonstration. This paper focuses on a new and efficient method to the teaching of power system analysis courses to the upper-division undergraduate students. The intent is to present MATPOWER to students as a good instructional tool to complement the teaching of power system analysis courses in the class. This would certainly facilitate the teaching and understanding of the subject matter better. The features and the relative merits which make the package preferred to some of the commercially available software packages, in certain applications, are highlighted in the paper. With self study in mind, the paper is written to simplify the daunting task of carrying out power flow analyses especially on large power networks. One illustrative example is examined in the paper. The power flow solution by the Newton-Raphson method is demonstrated using the conventional approach prior to solving it using the MATPOWER package. The result obtained using the package is guaranteed to be accurate and reasonably fast

Catalytic pyrolysis and a pyrolysis kinetic study of shredded printed circuit board for fuel recovery

Scrap printed circuit boards (PCBs) are the most abundant wastes that can be found in the landfills in Malaysia and this disposal certainly poses serious detrimental to the environment. This research aims to investigate optimum temperature for pyrolyzing waste PCBs, find out the best catalyst to be used in accelerating PCBs’ pyrolysis, select suitable ratio of catalyst to PCBs for higher oil yield and examine kinetics pyrolysis of the waste PCBs’ decomposition. Operating temperatures ranged from 200 to 350 ˚C of PCB’s pyrolysis were conducted with the optimum temperature obtained was 275 ˚C. Fluid cata-lytic cracking (FCC) catalyst, zeolite socony mobil-5 (ZSM-5), H-Y-type zeolite and dolomite were used to accelerate PCB’s pyrolysis at 275 ˚C and FCC was identified as the best catalyst to be used. Differ-ent ratios of FCC to waste PCBs such as 10:90, 20:80, 30:70, 40:60 and 50:50 were applied in the pyro-lysis at 275 ˚C and ratio of 10:90 was selected as the suitable ratio to be utilized for maximum yield. The kinetic study was done through thermogravimetric analysis on waste PCBs under various heating rates and different particle sizes. The GC-MS analysis revealed that compounds detected in the pyro-oil have the potential to be used as fuel

Distributed energy resources and benefits to the environment

The recently released report of the International Energy Outlook (IEO2009) projects an increase of 44% in the world energy demand from 2006 to 2030, and 77% rise in the net electricity generation worldwide in the same period. However, threatening in the said report is that 80% of the total generation in 2030 would be produced from fossil fuels. This global dependence on fossil fuels is dangerous to our environment in terms of their emissions unless specific policies and measures are put in place. Nevertheless, recent research reveals that a reduction in the emissions of these gases is possible with widespread adoption of distributed generation (DG) technologies that feed on renewable energy sources, in the generation of electric power. This paper gives a detailed overview of distributed energy resources technologies, and also discusses the devastating impacts of the conventional power plants feeding on fossil fuels to our environment. The study finally justifies how DG technologies could substantially reduce greenhouse gas emissions when fully adopted; hence, reducing the public concerns over human health risks caused by the conventional method of electricity generation

A new islanding detection scheme based on combination of slantlet transform and probabilistic neural network for grid-tied photovoltaic system

According to find islanding in a grid tied photovoltaic system, a combination of Slantlet Transform (SLT) and Probabilistic Neural Network (PNN) has been proposed in this paper. The SLT is used to extract the unique features from three phase voltage signals at the Point of Common Coupling (PCC). The produced features vector is fed to a probabilistic neural network classifier as input pattern which is used to predict islanding condition. The proposed technique is validated through comparing with islanding response time in different situations with the offered response time through Rate of Change of Frequency (ROCOF) method

Entrepreneurs’ intention to invest in current business: an empirical study of Malaysian SME entrepreneurs

Entrepreneurs’ intention to invest in their current businesses may play an important role in determining future sustainability, survival and growth of these businesses. Using a theoretical framework based on entrepreneurs’ goals attainment theory (EGAT), this study evaluated the relationship between entrepreneurs’ personal goal attainment and their intention to invest. The study employed a positivist methodological framework and gathered primary data from 285 Malaysian entrepreneurs through self-administered survey questionnaires. Regression analyses showed that entrepreneurs’ attainment of economic and intrinsic reward goals had significant positive relationships with their intention to invest. Desire for independence was considered as an important motivation for entrepreneurship. However, it was found that attainment of independence goals had no significant influence on entrepreneurs’ intention to invest. Further, it was also found that more educated entrepreneurs had stronger intention to invest in their current businesses

Available transfer capability (ATC): a review

With the advanced development of electrical power markets, large amount of electric power is consumed and transacted which require, accurate determination of Available Transfer Capability (ATC) and broadcasting the ATC information to prevent and relieve transmission congestion effectively. In this paper existing deterministic and probabilistic methods for calculating ATC, are reviewed. Some suggestions for dealing with the technique challenges are given for the future research

Voltage flicker estimation based on pair of inter-harmonics analysis method

This paper presents a voltage flicker estimation based on a pair of inter-harmonics analysis method. The proposed algorithm is able to estimate flicker frequency and amplitude changes of a voltage waveform. The correlation of the pair of inter-harmonics, flicker frequency, and amplitude changes are presented and their formulas highlighted. Experimental results indicate the amplitude of pair of inter-harmonics can detect the voltage flicker. Furthermore, the experimental results are compared with the measurement results obtained by using the Fluke power analyzer (Pst)

Thermal performance of ferrule designs for medium voltage cable jointing

Among breakdowns reported in Tenaga Nasional Berhad (TNB) Malaysia is about 60% of total breakdown is due to underground network failures. It was known that cable joint is the weakest part in the underground cable system and ferrule is one part of cable joint. The main reason of ferrule failure is due to excessive heat generated at the connection between conductor and ferrule. There are many ferrules available in the market. This study will focus on two types of ferrule and the experiment was setup to evaluate the thermal performance