M. S. Majid

Mathematical model of Compressed Air Energy Storage in smoothing 2MW wind turbine

This paper presents the mathematical modeling of Compressed Air Energy Storage, (CAES) in obtaining mechanical power generated from expander. Mechanical power is injected to a generator to generate electricity that will stabilize 2MW active power fluctuated caused by intermittent behavior of wind speed. The control system in maintaining dc-link voltage at constant value and control system in supplying generated power from CAES is also discussed here. The goals in using CAES are to smooth out the fluctuated power and increased low power integrated into the grid. This system is analyzed using SimPowerSystem of MATLAB/simulink. Results show that the jCAES is able to not only mitigate generated power but it also can promise constant power generated to grid even at low wind speed.

Analysis of distribution transformer losses and life expectancy using measured harmonic data

Three-phase distribution transformer in electrical power systems are usually designed for utilizing at the rated frequency and linear load. A different performance compared with that of the designed transformer occur when non-linear loads introduce harmonics to the supply. With the increasing use of nonlinear load the harmonic ay overheat the transformer leading to a poor power quality. The increased losses in the transformer due to the harmonic distortion can cause unnecessary winding loss and typical temperature rise. This paper presents the analysis and evaluation of distribution transformer losses under non-linear load by using real data. In this study, losses caused by harmonic and life of the distribution transformer were determined. Results show that an increase in the current harmonic distortion will increased in the current harmonic distortion will increase the transformer losses and hence decreased its life expectancy.

A review on optimal placement methods of distribution generation sources

Distributed Generation (DG) sources have attracted serious attention due to their potential solution for some issues, like the deregulation in power system, increasing the power consumption and the shortage of transmission capacities. The optimal placement of DG is necessary for maximizing the DG potential benefits in power system such as maintaining and/or improving reliability and stability. There are several research studies to determine the optimal DG location by their imposed constraints and objectives. However, the systematic principle for this issue is still an unsolved problem. This paper is reviewed some of the most popular DG placement methods, including 2/3 Rule, Analytical Methods, Optimal Power Flow and Evolutionary Computational Methods (Genetic Algorithm, Fuzzy Systems and Tabu Search). The related applications and advantages of each technique are expressed briefly. This paper provides helpful information and resources for the future studies in this area.

Demand Side Management Using Direct Load Control for Residential

Dramatic increase in the number of domestic consumers due to mass electrification will have implications for the national generation, transmission and distribution. The nature of the domestic load coincides with the evening peak which is more expensive to generate. This indicates the need for demand side management (DSM) in residential as a strategy to reduce the impact of domestic peaks on the national electricity load and related costs. This paper describes the software development written in Visual C++ 6.0 to control directly the residential loads through communicating with parallel port. Graphic user interface (GUI) was designed for the software. Comparison was done between load curve without controller and with controller. The result shows a reduction in energy consumption with the application of DSM controller. Hence, DSM application improves the management of both power and energy consumptions.

Modeling and simulation of grid connected Photovoltaic System for Malaysian climate using Matlab/Simulink

The impact of solar irradiance, ambient temperature and clearness index on the outdoor performance of poly-crystalline (poly-Si) PV modules is considered. This paper highlights the effect on the energy output by changing the clearness index for the Building Integrated Photovoltaic System (BIPV) in Malaysia. Simulation was implemented using MATLAB/SIMULINK and results are compared with the actual monitored data. A case study was presented for a 45.36 kWh system using poly-crystalline module and results show that the energy output differs from 7.23% to 8.52% with clearness index of 0.55 and hence clearness index also influenced the energy output besides solar irradiance and temperature.

Certain Considerations In Pricing Unbundled Transmission Services

In deregulated environment, the transmission network is considered to be the key factor of the electricity markets. One of the important issues in this context is how to charge the users for the use of transmission facilities in the fair way and at the same time allowing the transmission utilities to recover their transmission costs. Several methodologies have been developed to recover the cost of transmission services and to estimate the power contributed by single generating unit in lines and loads. Both developed methods attempt to allocate the charge of the use of the transmission system. This paper describes certain aspects to be considered in pricing the unbundled transmission services. These aspects cover the type of transmission services, the costs related to the services and the methods used to calculate the costs of transmission services. This paper also proposes a new approach to allocate the costs of the transmission services among the transmission user utilising the properties of MW-mile based method. A case study based on a 6-bus system is used to highlight the merit of the proposed approach over the existing approaches. The case study results show that the proposed approach provides a better economic signal in allocating the charges to the transmission user.

The reduction of Total Harmonic Distortion and electromagnetic interference in high pressure sodium street lighting using single stage electronic ballast

This paper presents the design of single stage electronic ballast for a conventional 250W High Pressure Sodium (HPS) street lighting. Historically the HPS street lighting operating hours is from sunset to dawn which is 12 hours in full brightness. The existing conventional street lighting HPS are powered by magnetic ballasts. The magnetic ballast is a device which consists of coil and core. It is an uncontrolled device, not energy efficient and generate flicker before it can give steady light. The use of electronic ballast provides a rapid start and energy efficient but will create electromagnetic interference and harmonic. This will reduce the circuit performance. To overcome the problems, the single stage design electronic ballast is used for the HPS lamp. The effect of the electromagnetic interference (EMI) and harmonic to the designed system is assessed. This is performed in three different stages; (i) with and without EMI filter, (ii) the half-bridge and (iii) the full-bridge inverter. For stage (ii) and (iii), the comparison of harmonic produced in electronic ballast was evaluated. The operating frequency for electronic ballast is 68 kHz. The findings show that the Total Harmonic Distortion current (THDi) of 5.55% for full bridge inverter compared to the half bridge inverter with THDi of 8.73%. A reduction of 36% of THD is obtained when full bridge inverter is applied. The current waveform result indicates a reduction of 25% without EMI filter from the original waveform. The reduction of both EMI and THDi can give benefit to street lighting system and energy efficiency.

Optimal power flow solution using evolutionary computation techniques

This paper presents evolutionary computation (EC) techniques and discusses their applicability to the optimal power flow (OPF) problem. The power flow problem is optimized to find the minimum fuel cost of all generating units while maintaining an acceptable system performance in terms of limits on the power outputs of generators, bus voltage and line flow. Different EC techniques such as genetic algorithm (GA), particle swarm optimization (PSO) and differential evolution (DE) are applied to solve the OPF problem for IEEE 30-bus system. The results are compared with the OPF solution obtained from MATPOWER that employs sequential quadratic programming to prove the effectiveness of the EC techniques. The computational results show that EC techniques work effectively and applicable to the OPF problem.

Electricity market models in restructured electricity supply industry

In the new era of modernity, the competitive environment has spread widely into all sectors including the electricity market. The evolution of electricity market model began since 1980s. A number of electricity market models have been introduced and each model is designed appropriately with its local condition. The selection of the model used depends on the justification determined by power utilities or regulatory policies taking into account the technical and economic aspect point of view. This paper discusses two electricity market models; single buyer market model and pool market model. A case study is carried out to compare the two market models in term of generation revenue. The Independent Power Producers (IPPs) and load profiles in Malaysia Electricity Supply Industry (MESI) is used for the case study.

Application of energy efficient motor in Malaysian industries

Electric motors are used extensively in every sector of the economy. They perform a wide range of duties throughout the industrial, commercial, residential and agricultural sectors. Motor systems are the largest industrial loads, on average accounting for more than 70 percent of all electricity consumption. Energy consumption of electric motor systems is an important economic and environmental issue. More than half the electricity generated in Malaysia is consumed by electric motor driven system applications. Therefore, industries can save considerable amounts of money on their electricity bills, if they employ motors of higher efficiency, and improve the energy efficiency of the systems driven by these motors. This paper presents test procedures to determine motor efficiency. A case study on the efficiency and improvement in energy usage by retrofitting the motors with high efficiency motors is also presented. This paper also shows the comparison in performance and cost benefits between standard motor and energy efficient motor using simple payback analysis.