Hashim Hizam

Review of control strategies for power quality conditioners

Active power filter appears to be a viable solution for power quality conditioning. With the emergence of fast computing devices, control strategies for active filters are continually changing aiming at near perfect compensation. This paper presents a review of the state-of-the-art control techniques in active filters and reactive power compensation. Considerable attention is paid to the reference voltage/current estimation and control strategies. Several techniques are discussed and compared in terms of performance and implementation.

A Novel Implementation for Generator Rotor Angle Stability Prediction Using an Adaptive Artificial Neural Network Application for Dynamic Security Assessment

This paper addresses a new approach for predicting the generator rotor angle using an adaptive artificial neural network (AANN) for power system stability. The aim of this work is to predict the stability status for each generator when the system is under a contingency. This is based on the initial condition of an operating point, which is represented by the generator rotor angle at a certain load level. An automatic data generation algorithm is developed for the training and testing process. The proposed method has been successfully tested on the IEEE 9-bus test system and the 87-bus system for Peninsular Malaysia.

Modelling and Prediction of Photovoltaic Power Output Using Artificial Neural Networks

This paper presents a solar power modelling method using artificial neural networks (ANNs). Two neural network structures, namely, general regression neural network (GRNN) feedforward back propagation (FFBP), have been used to model a photovoltaic panel output power and approximate the generated power. Both neural networks have four inputs and one output. The inputs are maximum temperature, minimum temperature, mean temperature, and irradiance; the output is the power. The data used in this paper started from January 1, 2006, until December 31, 2010. The five years of data were split into two parts: 2006–2008 and 2009-2010; the first part was used for training and the second part was used for testing the neural networks. A mathematical equation is used to estimate the generated power. At the end, both of these networks have shown good modelling performance; however, FFBP has shown a better performance comparing with GRNN.

Comparative Analysis of Probabilistic Neural Network, Radial Basis Function, and Feed-forward Neural Network for Fault Classification in Power Distribution Systems

Abstract This article presents a classification methodology based on probabilistic neural networks. To automatically select the training data and obtain the performance evaluation results, the “K-fold” cross-validation method is used. Then, the probabilistic neural network is compared with the feed-forward neural network and the radial basis function network. The goal is to propose a classifier that is capable of recognizing 11 classes of three-phase distribution system faults to solve the complex fault (three-phase short-circuit) classification problem for reducing the multiple-estimation problem to estimate the fault location in radial distribution systems. The data for the fault classifier is produced by DigSilent Power Factory, Integrated Power System Analysis Software on an IEEE 13-node test feeder. A selection of features or descriptors obtained from voltages and currents measured in the substation are analyzed and used as input of the probabilistic neural network classifier. It is shown that the probabilistic neural network approach can provide a fast and precise operation for various faults. The simulation results also show that the proposed model can successfully be used as an effective tool for solving complicated classification problems.

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 characteristics.

Application of smart power grid in developing countries

Smart grid, which is extensively new topic, is the next generation of power grid. Future modern grid will manage all parts of electrical power grid from generation to transmission and distribution by using intelligent methods. Smart grid progress in some developing countries is same to developed ones. In other parts of developing world, research works and pilot projects are newly started. Therefore, in the present work, a study of applied efforts in developing countries by regarding infrastructure of smart grid works was proposed. The analyses show that some countries like China, India and Brazil are pioneer on smart grid in developing world. As a conclusion, a progress pattern based on smart grid development in these three countries is proposed.

Broadly tunable multiwavelength fiber laser with bismuth-oxide EDF using large effective area fiber

A multiwavelength laser comb using 2.49 m Bismuth-oxide erbium-doped fiber (Bi-EDF) with different lengths of large effective area fiber (LEAF) in a ring cavity configuration is realized. The Bi-EDF is used as the linear gain medium and LEAF is used as the non-linear gain medium for stimulated Brillouin scattering. Out of the four different lengths, the longest length of 25 km LEAF exhibits the widest tuning range of 44 nm (1576 to 1620 nm) in the L-band at 264 mW pump power and 5 mW Brillouin pump power. In addition, a total of 15 output channels are achieved with total average output power of −8 dBm from this laser structure. All Brillouin Stokes signals exhibit high peak power of above −20 dBm per signal and their optical signal-to-noise ratio of greater than 15 dB.

Chemical enhancement materials for grounding purposes

It is an aim of this work in finding the best performed chemical enhancement material in order to provide the lowest impede path for fault currents to be dispersed into the earth in the shortest time possible. These fault currents are typically due to transients and they could be dangerous to the power system, equipment in it and the personnel involved with the system. Hence, it is desired that a grounding system is installed to provide such path to clear these fault currents from the power system in the manner that danger could be reduced. Such transients are generated by lightning, or switching action. Note that in this study, only lightning strike is considered. Lightning could create impulsive transient during its direct or indirect strikes to power system. This problem is normally prevented by installing a suitable grounding system to the power system. A grounding system will create a path for transient to be safely dispersed into the earth by providing lowest resistance path. This can be easily done using either natural or chemical enhancement materials. However, this work only reported the findings of having chemical enhancement materials in the vicinity of grounding system for protection against lightning. It is found that sodium chloride demonstrated the best performance in being enhancement material for earthing system on top of sodium thiosulphate, magnesium chloride, cuprum sulphate, and ammonium chloride.

Linear Feedback Controller for D-Statcom in DPG Fault Application

This paper presents the application of linear feedback controller on distribution static synchronous compensator (D-STATCOM) for mitigating double phase to ground (DPG) fault at the distribution system. The pole placement technique is applied by shifting the existing poles to the new poles locations for fast response compare to the conventional controller. This type of inverter control is very useful in D-STATCOM application which controls the inverter to inject the unbalanced current or voltage or both for mitigating the fault condition that occurs at the distribution system. The controller will give respond to the lines that are affected by the fault and restore the system to its normal conditions. The simulation and design of the controller is done using MATLAB software with Power Blockset Toolbox and SIMULINK

Available Transfer Capability Calculation

The maximum power that can be transferred from one area to another area is called transfer capability. In 1996, North American Electric Reliability Council (NERC) established a framework for Available Transfer Capability (ATC) definition and evaluation. According to the NERC definition, ATC is the transfer capability remaining between two points above and beyond already committed uses (NERC, 1996). The ATC value between two points is given as: