Syafrudin Masri

Single phase grid tie inverter for photovoltaic application

This paper present a grid tie inverter for photovoltaic, PV application with a combination switching strategy of square wave and the sinusoidal pulse width modulation, SPWM. The combination switching strategy will be discussed and the performance of the inverter also will be simulated under grid tie condition in SIMULINK. Besides that, the strategy of sending power into the grid also will be discussed.

Study on the electromagnetic force affected by short-circuit current in vertical and horizontal arrangement of busbar system

Each busbar conductor of a phase is subjected to a force due to the short-circuit currents. In this paper, the electromagnetic forces affected by the short-circuit current in three-phase busbar conductor are calculated in vertical and horizontal arrangement. The short-circuit current densities are calculated mathematically. The calculations are performed by assuming a peak value of steady-state ac current is equal to the peak value of the short-circuit current. The electromagnetic forces due to the short-circuit current are calculated according to the equation introduced by IEC Standards 865/1993. The electromagnetic force generated in vertical arrangement is compared with the horizontal of busbar. The result depicted that the busbar in vertical arrangement has about 2 times higher electromagnetic force compared with that in horizontal arrangement. The arrangement of the busbar obviously influences the strength of electromagnetic force due to short-circuit current. Furthermore, the electromagnetic force obtained from the simulation by finite element method in vertical arrangement was agree with the calculation obtained using IEC Standard 865/1993.

Wind speed analysis at Nibong Tebal

Wind speed is the fundamental parameter in the design and study the potential of wind energy at certain area. In this research, Nibong Tebal has been selected as a case study for grassland type in order to evaluate the variation and an availability of wind speed. Hellman exponential law is used which correlates the wind speed readings at two different heights. Result shows that at height of 10m a monthly average of 163.14Wh energy has been produced at Nibong Tebal.

Investigation of electromagnetic force during short-circuit test in three-phase busbar system

All busbar systems are subjected to electromagnetic forces which may cause permanent mechanical deformation and damage if large electromagnetic force occurs due to short-circuit current. Therefore, the predictions of electromagnetic force on the three-phase busbar system is very important, especially to analyze it effect on the mechanical structure of busbar system. In this paper, two finite element models of busbar system having different rated currents are presented. Each model of busbar system has different mechanical dimensions. The electromagnetic forces generated in conducting busbars are analyzed under short-circuit conditions. The electromagnetic force is obtained using transient analysis by applying Maxwell Stress equation. Higher peak short-circuit current contributes to the generation of higher electromagnetic force between parallel conductors. The finite element models predict the busbars will experience peak short-circuit current of 63kA and 73.5kA, thus, generating about 62.5242 N/mm and 67.8617 N/mm of electromagnetic forces respectively, in between the conducting busbars. Optimal design for the mechanical dimensions and supporting structure for the three-phase busbar system can be intensively simulated taking into account the maximum electromagnetic force allowable. The results indicate that the magnitude electromagnetic force can be reduced by 4%–7% when the dimensions of conducting busbar thickness and its spacing are increased by 1mm. The results obtained are useful for the mechanical design and determination of supporting structure of the busbar system.

LLC Resonant Converter Based Incremental Conductance Maximum Power Point Tracking System for PV Applications

Maximum power point tracking is one of the crucial element in photovoltaic (PV) power systems. Most of the conventional maximum power point tracking (MPPT) systems utilize pulse width modulated (PWM) dc-dc converter. PWM dc-dc converters usually have higher switching loss and high electromagnetic interference. On the other hand, resonant converters show good efficiency, soft switching capabilities and capable of high frequency operation over the conventional PWM converters. This paper proposes an incremental conductance MPPT using LLC resonant converter for PV power systems. The converter and the MPPT algorithm are implemented using MATLAB Simulink environment. The simulation results show the good performance of LLC resonant converter for maximum power tracking under varying environmental conditions.

Inter-area oscillation damping techniques in wind power plants: A review

The deep penetration of wind energy in the modern power systems introduced many challenges due to the variability and limited predictability of wind. Wind power plants can provide ancillary services to the grid such as voltage support and reactive power compensation. The inter-area oscillation is one of the phenomena that adversely affect power transmission through weak tie-lines. Since the wind power plants are connected in remote grid areas, they can effectively contribute to damp these low-frequency oscillations. This paper investigates the techniques used in wind power plants to support grid stability by increasing the damping of the inter-area oscillations.

Load Flow Analysis Using Improved Newton-Raphson Method

This paper describes a simple, reliable and swift load-flow solution method with a wide range of practical application. It is attractive for accurate or approximate off-and on-line calculations for routine and contingency purposes. It is applicable for networks of any size and can be executed effectively on computers. The method is a development on conventional load flow principle and its precise algorithm form has been determined to bring improvement to the conventional techniques. This paper presents a comparative study of the new constant Jacobian matrix load flow method built based on several conventional NR load flow methods. Assumptions are made so as to make the matrix constant, thus eliminating the need of calculating the matrix in every iteration. The proposed method exhibits better computation speed.

The Energy Efficiency Improvement and Management Program for Academic’s Building, Engineering Campus, Universiti Sains Malaysia

This paper presents the case study on the energy efficiency improvement and proposes the energy management program to reveal the potential of energy saving in School of Chemical Engineering (SCE)’s building, Engineering Campus, USM, which has high energy index among the academic building. The effective solution to control the energy conservation is by taking care the energy efficiency on the energy consumption in buildings through the Energy Audit and the Efficient Energy Management (EEMs) program. With reduction in consumer load, there is an opportunity to lower the load curve along with saving in energy bill due to the lowering the energy consumed.

Inter-area Oscillation Damping in Power Systems with Deep Penetration of Wind Energy

The rapid growth of energy demand in the recent years mandated exploiting energy resources alternative to the conventional fossil fuel-based resources. Nowadays, the renewable energy resources became a fundamental component of the current power systems. Numerous challenges are induced by these recent bulk systems such as low-frequency inter-area oscillations. This paper investigates three methods to damp inter-area oscillation in power systems with deep penetration of wind energy, which are: incorporating power system stabilizers in the automatic voltage regulator controls of the conventional generator, implementing a static var compensator in one of the system busbars, and implementing a high voltage dc transmission system to connect weakly-tied areas within the system. These methods helped increase inter-area oscillation damping when implemented in a modified system based on the classical two-area system.

Design of a PEV battery charger with high power factor using half-bridge LLC-SRC operating at resonance frequency

This paper presents a two stage battery charger for plug-in electric vehicles (PEV) based on half-bridge LLC series resonant converter (SRC) operating at resonance frequency. The first stage is power factor correction (PFC) stage comprising of boost converter topology using hysteresis band control of inductor current. The PFC stage reduces the total harmonic distortion (THD) of the line current for achieving high power factor and regulates the voltage to follow the battery voltage at DC link capacitor. The input of the boost converter is a single phase 50 Hz, 220V AC from grid. At the second stage, a half-bridge LLC-SRC is used for constant-current, constant-voltage (CC-CV) based battery charging and for providing galvanic isolation. The resonant converter is designed to operate around resonance frequency to have maximum efficiency and low turn-off current of power switches to reduce switching losses. The circuit is simulated using MATLAB Simulink with 1.5 kW maximum output power. Simulation results show that the PFC stage achieves THD less than 0.07% and high power factor value as 0.9976. The DC/DC stage meets all the CC-CV charging requirements of the battery over wide voltage range 320V-420V for depleted to fully charged battery.