Md. Abdus Salam

Modeling charging demands of various types of electric vehicles in an actual distribution system

Developing an elaborate load model for electric vehicles (EVs) charging is of great importance. First, analysis about the charging behaviors of five types of EVs is carried out based on survey results. Subsequently, a smart charging strategy which not only takes into account the user behaviors but also considers the real-time electricity price, is presented to regulate the charging behaviors of EVs by providing economic incentives. Considering the uncertainties of the charge price, the robust optimization model for smart charging is then developed and AMPL/CPLEX, a highly efficient commercial solver, is employed to obtain the optimal charging plan. Finally, a typical Hangzhou distribution system is employed to illustrate the efficiency of the proposed model. The results show that the existing distribution network can accommodate EVs more efficiently by employing the proposed decentralized smart charging strategy in comparison with the uncontrolled charging strategy.

Investigation of the effect of weather conditions on solar radiation in Brunei Darussalam

The amount of solar radiation received on the earths surface is known to be highly influenced by the weather conditions and the geography of a particular area. This paper presents some results of an investigation that was carried out to find the effects of weather patterns on the solar radiation in Brunei Darussalam, a small country that experiences equatorial climate due to its geographical location. Weather data were collected at a suitable location in the University Brunei Darussalam (UBD) and were compared with the available data provided by the Brunei Darussalam Meteorological Services (BDMS). It has been found that the solar radiation is directly proportional to the atmospheric temperature while it is inversely proportional to the relative humidity. It has also been found that wind speed has little influence on solar radiation. Functional relationships between the solar radiation and the atmospheric temperature, and between the solar radiation and the relative humidity have also been developed from the BDMS weather data. Finally, an artificial neural network (ANN) model has been developed for training and testing the solar radiation data with the inputs of temperature and relative humidity, and a coefficient of determination of around 99% was achieved. This set of data containing all the aforementioned results may serve as a guideline on the solar radiation pattern in the geographical areas around the equator.

Three-Phase Circuits

Single-phase circuit with its detail analysis has been presented in the previous chapter. Three-phase circuits are most common for generation, transmission and distribution of electric power. Over single-phase circuits, three-phase circuits or systems have many advantages such as better voltage regulation and require only three-fourth weight of the copper to transmit the same amount of power over a fixed distance at a given voltage, more economical for transmitting power at a constant power loss. Three-phase machines are smaller, simpler in construction and have better operating characteristics.

Capacitors and Inductors

Resistor, with different laws and network theorems, has already been discussed and analysed in the previous chapters. Like a resistor, capacitor and inductor are also important linear circuit elements. Capacitor and inductor do not dissipate energy like resistor, but store energy when these elements are connected to energy source. Later on, this stored energy can be used for other applications.

Fundamental Electrical Terms

It is essential to understand the fundamental of electrical terms to comprehend any electrical phenomena. This chapter presents these necessary concepts and components as a first stepping stone in understanding any underlying electrical principles. In addition, it introduces the core measuring equipment in the electrical domain along with charge, current, voltage, power, energy, resistance, semiconductor and insulator.

Different Methods for Circuit Analysis

Fundamental electrical laws and the associated parameters have already been discussed in the previous chapters. Additional analytical methods have been developed to analyse practical electrical circuits with more than one source. These methods include mesh analysis and node voltage analysis, also known as nodal analysis. Kirchhoff’s voltage law (KVL) is used in the mesh analysis while Kirchhoff’s current law (KCL) is used in the nodal analysis. In these analytical methods, Cramer’s rule appears to be a handy tool that helps to solve the system of linear equations after the application of Kirchhoff’s laws in an electrical circuit. Upon introducing Cramer’s rule, this chapter presents the theoretical foundations on supermesh, supernode, mesh and nodal analysis with dependent and independent sources.

AC Circuit Analysis

Analysis of AC circuit plays an important role in designing and testing of power transmission networks, electrical and electronic equipment. In this case, sound knowledge of AC circuit analysis is very important. The AC circuit fundamentals and KVL, KCL and delta–wye conversion in the phasor domain have been discussed in Chap. 6. This chapter presents mesh and nodal analysis on AC circuit along with different network theorems, which have already been introduced in Chap. 4. These theorems include superposition, Thevenin’s, Norton’s and maximum power transfer theorems.

AC Power Analysis

AC generator, transformer and other related high-voltage devices are required to generate, transmit and distribute alternating voltage and current. These pieces of equipment are rated in terms of mega watt (MW) and mega voltage-ampere (MVA). Electrical appliances, such as DVD player, television, microwave oven, light bulb, refrigerator, ceiling fan and many more are rated in terms of watt (W). It requires a careful attention in designing those kinds of equipment to address their power ratings, which in turn address the varying electricity bill. In this case, analysis of AC power plays an important role. This chapter discusses different AC power analytical technique, in terms of instantaneous power, average power, complex power, power factor, maximum power transfer theorem and power factor correction.

Characterization of electric and magnetic fields near residential and industrial areas in brunei darussalam

Transmission lines near residential areas radiate electric and magnetic fields (EMF) which create cancer disease in the human health. Measurement of electric and magnetic fields are very important near high voltage transmission lines. EMF have been measured near residential and industrial areas using EMDEX II equipment. An empirical relationship between the electric field with the lateral distance and magnetic field with the lateral distance have been developed for both areas. The determination of coefficients for residential area in case of electric and magnetic fields are found to be 0.98 and 0.99 respectively.

Investigation of the role of void sizes for failure of high voltage bushing

This paper presents the investigation of the root causes of the high voltage bushing failure in a Power Station which occurred on July 12, 2015 in Brunei Darussalam. Upon physically examining the burning parts of the bushing, a computer simulation was carried out to analyze the contribution of void sizes towards the failure of bushing. COMSOL Multiphysics software was used for the analysis. For simulation, an actual diagram of the high voltage bushing was drawn using the Autodesk Inventor. Different scenarios with the presence of 1 mm and 1.5 mm diameter void sizes were considered in the XLPE insulation part of the high voltage bushing. Considering different depths of 1 mm, 5 mm and 11 mm, respectively, simulation results were obtained for void sizes with full, 50% less and without oil insulations. The simulation results showed that the bushing failure occurred due to oil leakage and different sizes of voids. It was also summarized that the physical inspection could help in predicting and preventing high voltage bushing failure in the future.