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In today’s modern power devices and rapid growth power demands, the need for precise and accurate protection relays is a must for the power distribution system. That is, to segregate faulty sectors within fewer cycles, power relays should perform at the highest level of accuracy to detect abnormal conditions in power distribution. Therefore, this work will investigate the enhancement of the numerical relay testing in terms of harmonic distortions effect on the digitized output waveform as direct causes of relay failures. However, as it is an expensive process of testing the digitizing element of the numerical relay, this paper proposes a new algorithm of Wavelet transforms in power quality signal processing testing using MATLAB simulation. As this newly proposed method of advanced waveform analysis algorithm will enhance the testing process of digitizing elements, and reduce data compiling complexity, a comparison between conventional Fourier Transforms testing and Wavelet algorithm under abnormal conditions will be simulated based on inserting multi harmonics effect. As a result, based on the Wavelet bank of filters, de-noising, and decomposition structure filters, Wavelet has provided promising results in defining the effect of waveform distortion tripping time, fault location, total harmonic distortion, signal-to-noise ratio, and spurious-free dynamic range.

This paper presents a robust sliding mode controller of DC-DC buck converter for renewable energy applications, such as photovoltaic systems in off-grid configurations. Photovoltaic systems in off-grid configuration are exposed to significant variations in input voltage and power loads. The proposed sliding mode controller presents a simple and efficient method of continuously updating the duty cycle of a pulse width modulation unit (PWM) of a buck converter. The PWM unit is operated at constant switching frequency of 10 kHz carrier signal and varying duty cycle. The differences in input voltage and power load are treated as two bounded uncertainties, thus eliminating the need for input voltage sensor and output current sensors leaving the system with a single sensor required to measure the converter output voltage. That is, measured output voltage is compared with the reference voltage to continuously update the average duty cycle value of PWM unit. Adjustment of PWM duty cycle is performed while maintaining the sliding condition always fulfilled. The simulation results of the proposed controller showed robustness and accuracy against power load fluctuation, changes in desired output voltage, and variations in the input supply voltage that may result from the varying level of irradiance and temperature.

This paper evaluates the technical aspects of grid-connected photovoltaic (PV) systems and distributed energy resources (DERs) interconnection grid codes. The advanced functions of smart PV inverters and smart grid solutions are discussed as well as the gaps of the existing grid codes that hinder DER ancillary services. An online survey targeted the key stakeholders and industry experts have been conducted to investigate advanced inverters potential of providing DER ancillary services to distribution grids. The survey results are discussed in details and recommendations for the reactive power support of DER inverters and DER interconnection codes enhancements are presented.Keywords: Distributed Energy Sources, Distributed Energy Resource Interconnection Grid Codes, Distributed Energy Resource Ancillary Services, Distributed Energy Resource Integration, Advanced Inverters Capabilities, Volt/Var ControlJEL Classifications: P48, Q42, Q48DOI: https://doi.org/10.32479/ijeep.8758

This paper presents a two-stage grid-connected PV system with reactive power management capability. The proposed model can send phase-shifted current to the grid during a low-voltage ride through (LVRT) to recover the voltage levels of the grid’s feeders. The novelty of the proposed algorithm, unlike the common methods, is that it does not need to disable the maximum power point tracking (MPPT) state while managing active and reactive power injection simultaneously. Moreover, the new method promotes a safety factor by offering overcurrent protection to the PV inverter. The phase-locked loop based on the synchronous reference frame (SRF-PLL) is optimized using a genetic algorithm (GA). The settling time of SRF-PLL’s step response is minimized, and the frequency dynamics are improved to enhance synchronization during LVRT. The system’s performance is tested and verified using MATLAB/Simulink simulations. The obtained results prove the effectiveness of the proposed control algorithm in managing reactive power interventions. The optimized phase-locked loop shows robust performance and is compared to the conventional low-gain PLL to spot the enhancement.

The use of induction machines has gained fast popularity in many aspects of today’s energy applications and industrial productions. However, just as with any other machine, failure is expected due to a variety of faults in component and system levels. Therefore, it is necessary to improve machine reliability by performing preventive maintenance and exploring faulty indications in advance to avoid future failures. In normal operation, a distinct machine sound signature can be identify. Therefore, at any faulty operation, diagnosis of potential error can be defined based on output signature sound data analysis. Yet, this process of monitoring induction machine sounds and vibration can be hectic and extensive in terms of collecting data and compiling analysis. That is, a huge number of data samples need to be collected and stored in order to define abnormality operation. Therefore, in this work, wavelet-based algorithms were developed as an analysis process to analyze collected data and identify abnormality, with much fewer data samples and compiling process, as special prosperity of wavelet transform. As a result, MATLAB codes were implemented to analyze data based on sound signature technique and wavelet transform algorithms to show a significant improvement in identifying potential error and abnormality conditions.

This paper presents direct control of active and reactive power using grid voltage modulation for single-phase grid-connected photovoltaic inverter. A design of type-1 servo system based on pole-placement method is proposed to control the power flow using a simplified multiple-input multiple-output (MIMO) model of the system. Phase-locked loop (PLL) with a quarter cycle time delay is used to estimate the grid phase angle for the purpose of performing the stationary and synchronous reference frame transformation. Unipolar pulse width modulation (PWM) technique is used to control a single-phase inverter with 2.7 KVA capacity connected to the photovoltaic system. The proposed controller can simply be tuned using minimum number of controller gains to achieve the transient and steady-state performance requirements. The proposed system, was capable of operating for a wide range of solar irradiance levels with a power factor in the range of 0.95 (leading/lagging), for the reactive power compensation purposes.

Biodiesel production had received a considerable attention as a green, non-toxic and renewable alternative to petroleum diesel. To avoid using vegetable oils, which are expensive and compete with food, as feedstock, waste oils have been proposed. However, these waste materials contain a large amount of free fatty acids that complicates the production process. In this work, biodiesel production using an alternative feedstock; namely oils from date-pits, has been investigated. These oils have the same favorable features of straight oils, and at the same time are considered waste, since they are extracted from a waste material. The yield of oils extracted using n-hexane in a Soxhlet apparatus was compared to that of oils extracted using methanol-chloroform solvent mixture. The extracted oils were then converted to biodiesel via transesterification with methanol in presence of Novozym&#174435 or Eversa&#174Transform. The highest oils extraction yield of 11.7%, per dry weight sample, was obtained using Soxhlet extraction apparatus compared to 8.9% using methanol-chloroform mixture. The highest biodiesel production yield was 30% of the oil used, achieved after 6 hours using Novozym&#174435 at 40°C, 5:1 methanol to oil molar ratio and 10wt% enzyme loading. By using a chemical alkaline catalyst, NaOH, at the same conditions, the yield was 27%.

The high penetration level of photovoltaic (PV) generation in distribution networks not only brings benefits like carbon savings, but also induces undesirable outcomes, like more harmonic components and voltage fluctuations. Driven by decreasing costs of energy storage, the focus of this paper is to investigate the feasibility of applying energy storage in the grid-connected PV system to mitigate its intermittency. Firstly, to appreciate the functionality of storage, a generic PV-battery-supercapacitor model was simulated in MATLAB/Simulink, and a flat load profile was obtained to enhance predictability from the network management point of view. However, the usage of supercapacitors at the residential level is limited, due to its high startup costs. Secondly, a detailed residential PV-battery model was implemented in the System Advisor Model (SAM) based on local data in Dubai. The optimal sizing of a battery system was determined by assessing two criteria: The number of excursions, and average target power, which are contradictory in optimization process. Statistical indicators show that a properly sized battery system can alleviate network fluctuations. The proposed sizing method can be also applied to other PV-storage systems. Finally, economic studies of PV-battery system demonstrated its competitiveness against standalone PV systems under appropriate tariff incentives.

The high penetration level of Photovoltaic (PV) generation in distribution network reduces carbon emissions but also becomes problematic in terms of network management. Harmonic distortion is the main factor studied in this paper and a typical three-bus distribution network is built in MATLAB/Simulink to understand the harmonics problem. Results show that current harmonics are more vulnerable to fluctuate compared to voltage harmonics. Based on existing harmonic standards, total demand distortion of current (TDDi) is evaluated to estimate maximum PV penetration level at Point of Common Coupling (PCC), and the maximum acceptable TDDi at each bus differs according to specific loading and short-circuit levels. Meanwhile, total harmonic distortion of current (THDi) at inverter outputs represents inverter performance. Instead of assessing at standard test conditions (STC), the impact of irradiance variations is studied. Low irradiance results in an increased THDi of the inverter whilst doesn't explicitly affect TDDi at PCC. A simple and low-cost solution is proposed to dynamically vary the settings of inverter's filter elements against irradiance, and harmonic distortion at low irradiance of the inverter is successfully mitigated.

Green building regulations in the United Arab Emirates are required to obtain building permits so that future construction projects can create a sustainable living environment. Emirates such as Abu Dhabi, Dubai, and Sharjah have specific green building regulations, whereas other emirates follow Abu Dhabi&rsquo, s regulatory criteria. Previous work fails to present a techno-economic cross-code analysis for various green building regulations in the UAE by evaluating energy and water performance. A case study using an existing high-rise green office building was formulated using the Integrated Environmental Solution: Virtual Environment (IES-VE) platform and the U.S. Leadership in Energy and Environmental Design (U.S. LEED) water consumption evaluation tool to study its energy and water performance, respectively. The archived results were used to devise an economic study based on the discounted cash flow technique. The principal findings of this research allowed us to determine a cross-code analysis and propose cost-effective trade-offs. These will aid the consultants and contractors in choosing appropriate green building regulations in the UAE by highlighting the potential of each parameter within green building regulations in terms of energy, water, and economic performance.

This chapter aims to introduce the reader in general, and project managers in particular, to the basic concepts and applications of renewable energy (RE) with emphasis on the various renewable energy technologies (RTEs), emerging as an alternative to traditional energy sources, in an applied, practical and project-focused context. The chapter builds on academic research-based cases studies conducted by the authors. The first case relates to a real-life project which will be the first advanced biofuels refinery to be built in the Middle Eastb with an estimated cost of $700m and commercial operation date in 2022. The financial close date is scheduled for the end of Q4, 2018, and it is expected to have a lower cost of production compared to European and US refineries. The second case study concerns the feasibility study to build a waste-to-energy (WTE) incineration plant in Dubai. It provides project managers with useful insight into the details of this vital initiation stage for this type of project, based on a real-life data set, in an applied research context. The details of both cases can be found on: https://www.goodfellowpublishers.com/sustprojman. The first few sections of the chapter set up the scene for the case studies by presenting brief definitions of the basic concepts of RE and various RETs in the context of sustainable development. Then at the start of each case study, a brief introduction to the specifics of the case is presented.

This paper presents a control scheme for a photovoltaic (PV) system that uses a single-phase grid-connected inverter with low-voltage ride-through (LVRT) capability. In this scheme, two PI regulators are used to adjust the power angle and voltage modulation index of the inverter; therefore, controlling the inverter’s active and reactive output power, respectively. A fuzzy logic controller (FLC) is also implemented to manage the inverter’s operation during the LVRT operation. The FLC adjusts (or de-rates) the inverter’s reference active and reactive power commands based on the grid voltage sag and the power available from the PV system. Therefore, the inverter operation has been divided into two modes: (i) Maximum power point tracking (MPPT) during the normal operating conditions of the grid, and (ii) LVRT support when the grid is operating under faulty conditions. In the LVRT mode, the de-rating of the inverter active output power allows for injection of some reactive power, hence providing voltage support to the grid and enhancing the utilization factor of the inverter’s capacity. The proposed system was modelled and simulated using MATLAB Simulink. The simulation results showed good system performance in response to changes in reference power command, and in adjusting the amount of active and reactive power injected into the grid.

Coal-based Integrated Gasification Combined Cycle (IGCC) power plants show obvious gains over conventional pulverized coal power plants by achieving higher efficiency, lower carbon emissions and lower energy penalty for incorporating different carbon capture and storage (CCS) technologies. However, due to the lack of standardised designs, current IGCC-CCS projects are hindered by higher capital expenditures limiting their commercial implementation. Therefore, the key challenge is carrying out a techno-economic optimisation of IGCC-CCS power plants to ensure compatible power generation efficiency and accessibility. This study aims to optimise the performance of a coal-based IGCC plant with two different CCS technologies (double-stage Selexol absorption cycle and Ni-based chemical looping combustion (CLC) process) through intensive process simulation, heat integration and economic analysis. Heat integration has increased the net plant efficiency by more than 12% and decreased the levelised cost of electricity (LCOE) no less than 5 cents kWh−1. The CLC technology offered near-zero carbon emissions with higher plant efficiency and lower value of LCOE. Decreasing the CO2 capture rate by Selexol caused a decrease in LCOE and an increase in the corresponding CO2 specific emissions. Therefore, an appropriate decarbonisation scenario depends on a trade-off between the degree of carbon capture and the allowed CO2 specific emissions.

Energy and water infrastructure in Abu Dhabi provides a strong example of the interconnection between energy and water, where the majority of its electricity and water demand is jointly produced from cogeneration plants. The total cost of fuel used for cogeneration plants are heavily depending on the efficiency level of end-use energy and water consumption. Buildings are the major electricity and water consumers with 84.6% and 92.2% respectively from the entire demand. The aim of this study is to analyze the energy and water consumption reduction by implementing Estidama pearl regulations and compare it with Business as Usual -the normal execution of things as they always do-for three sample buildings (villa, multistory residential and office building). For energy assessment, eQUEST software was used to examine the energy performance of the chosen buildings and to evaluate the energy saving potential after applying Estidama requirements. While for water assessment; Estidama and LEED calculation tools were used to do the same. The results of energy simulation and water analysis of the chosen buildings showed a potential of electricity reduction between 31% and 38% and a potential of water reduction between 22% and 36% depending on building type and other parameters. Also, a total monetary savings of 19 Billion AED can be achieved cumulatively over ten years period (2011–2020) after Estidama regulations have been applied. In addition, a reduction of 31.4 Million ton of CO2eq cumulatively can be achieved.

According to IRENA the number of countries adopted a target to ratify the renewable energy on their electricity grid went from 43 countries to 164 over a course of 10 years only. These targets which will increase renewable energy share on the electricity grid, implies the use of Distributed Generation (DG) like roof-top PV panels or the construction of small scale dispersed renewable-based power plant like wind or PV farms. The aim of this paper is to study the impacts of high PV and wind penetration into the grid. To address these impacts, a comprehensive study performed on a test system provided by IEEE to model the integration of DG plants into a 33kV distribution network using Etap software. Three levels of integration were modeled to reflect the impact of DG plants penetration on gradual basis, 6 scenarios have been assumed and two types of tests have been carried out to investigate their impact on the grid; fault level and frequency transient stability were performed individually at each level of penetration. Additionally, in order to examine the grid performance during extreme weather conditions, several events have been assumed to model the intermittent properties of renewable energy generation. The obtained results showed very good performance of the grid for penetration less than 30% while higher level of PV and wind penetration requires further attention and modification on the grid side.

The aim of this study is to model and design a hybrid renewable energy system for the remote area in Ras Musherib located in the western region of Abu Dhabi. The hybrid system, which consists of photovoltaic (PV) array, wind turbines, batteries and diesel generators, is designed to meet three known electric loads, 500 kW, 1 MW, and 5 MW to be able to fulfill the primary load for 250, 500 and 2500 households. Different combination of wind turbines, PV, batteries and generators were evaluated in order to determine the optimal combination of the hybrid system based on the lower Net Present Cost method. The proposed hybrid system is modeled, optimized and simulated using Hybrid Optimization Model for Electric Renewable (HOMER). The obtained results show that the hybrid system with 15% of photovoltaic and 30% of wind turbine penetration found to be the optimal system for 500 kW average load with initial cost of $4,040,000 and total net present cost of $14,504,952 over 25 years. The reduction in CO2 emission achieved in this study for the 500 kW optimal hybrid system is 37% compared to the conventional diesel generator only power system.

Connecting a single-phase or three-phase inverter to the grid in distributed generation applications requires synchronization with the grid. Synchronization of an inverter-connected distributed generation units in its basic form necessitates accurate information about the frequency and phase angle of the utility grid. Phase Locked Loop (PLL) circuit is usually used for the purpose of synchronization. However, deviation in the grid frequency from nominal value will cause errors in the PLL estimated outputs, and that’s a major drawback. Moreover, if the grid is heavily distorted with low order harmonics the estimation of the grid phase angle deteriorates resulting in higher oscillations (errors) appearing in the synchronization voltage signals. This paper proposes a modified time delay PLL (MTDPLL) technique that continuously updates a variable time delay unit to keep track of the variation in the grid frequency. The MTDPLL is implemented along a Multi-Harmonic Decoupling Cell (MHDC) to overcome the effects of distortion caused by gird lower order harmonics. The performance of the proposed MTDPLL is verified by simulation and compared in terms of performance and accuracy with recent PLL techniques.

The main aim of this research work is to assess the impact of wind farm integration on existing electricity grid in UAE and its protection system. The case study considered in this research work is 132 kV Dubai transmission network. The grid integration model was built using MATLAB Simulink software including grid parameters and 1.5 MW doubly-fed induction generator (DFIG) model. The DFIG generator was enhanced with AC crowbar, DC chopper and low voltage ride-through (LVRT) based control components which were built using MATLAB Simulink. The protection relays used in this study are differential protection, directional overcurrent and earth fault protection. The protection algorithms were programmed in MATLAB scripts and tested to different fault scenarios extracted from the integration built model. The protection relays' performance results are presented and analysed in this paper. The obtained results showed the excellent performance of differential relays and the defects of Directional relays' response in terms of reliable protection system performance due to transient disturbances effect on the grid. The study outcomes were used to recommend the design of suitable protection scheme for the interface transmission line to wind farm integration projects in Dubai.

Energy and water are closely linked and dependent resources where energy production requires a large amount of water and in contrast huge amount of energy is needed to extract, treat, desalinate, transport and distribute water. Abu Dhabi provides a strong example of the interconnection between energy and water, where the majority of its electricity and water demand is jointly produced from cogeneration plants. The total cost of fuel used for cogeneration plants are heavily depending on the efficiency level of end-use energy and water consumption. Buildings are the major electricity and water consumers in Abu Dhabi, with 84.6 and 92.2 % respectively from the entire demand. In the case of Abu Dhabi; adopting the Estidama pearl rating system for all new constructed buildings will reduce water and energy consumption by considerable amounts. The aim of this study is to analyze the energy and water consumption reduction by implementing Estidama regulations and compare it with Business as Usual—the normal execution of things as they always do—for three sample buildings (villa, multistory residential and office building). The results of energy simulation and water analysis of the chosen buildings showed a potential of electricity reduction between 31 and 38 % and a potential of water reduction between 22 and 36 % depending on building type and other parameters. Also, a total monitory savings of 19 Billion AED can be achieved accumulatively over 10 years period (2011–2020) after Estidama regulations have been applied. In addition, 31.4 Million ton of CO2eq cumulatively can be abated.

This paper presents a renewable energy model which combines the concepts of wind pumps, pumped hydro and micro hydroelectricity. The proposed model recovers energy from low speed winds and eliminates the requirement of energy storage in batteries or grid connection. After establishing the suitability of the model theoretically, workable models are visualized using commercially available components. Two designs based on this model are studied for their performance, and resultant data has been critically analyzed to establish the trend and their commercial feasibility. One of the two designs studied is a standalone tower that can feed a house or a small villa, which also can be installed at any point of need. The second design is building integrated where the system components are mounted on a building. Theoretical findings are validated by simulating through software, MATLAB. The obtained results showed the superiority of the proposed model over the conventional three blade wind turbines for wind speed less than 6 m/s.

This paper presents the implementation of vertical and horizontal integration of engineering education in an early design project. In this project, multi discipline first year engineering students were asked to design, build and test a device which can generate electricity from green energy sources. The project is embedded in the undergraduate mechanical engineering science course which is a core course for mechanical, automotive, engineering and management and civil engineering students. The structure of the project involves horizontally four first year students from different engineering departments and vertically a fourth year student as a group leader. The primary aims of this study were to investigate the applicability, efficiency and reflections of the early design project in developing the design skills and enhancing the student learning experience. Quantitative and qualitative surveys were conducted and analyzed to capture the reflections of the students and the project supervisors involved. The obtained results showed that the proposed early design project contributed to the personal gain of knowledge of students, improved their design skills and engaged them in constructive multi-disciplinary collaborative work. Also it demonstrated the importance of this design project in attaining the learning from practice and developing self-learning and presentation skills.

Induction motor is the workhouse of industry and particular attention is required to monitor and control it. An induction motor draws a high starting current and develops a high torque during start-up. The high starting current often causes problem such as voltage dips which will be penalized by the energy companies. Various motor starters were introduced to overcome this problem. The different motors starters available in Malaysian market are discussed and analyzed in this paper; these include both conventional electromechanical starters and power electronic drives. The advantages, disadvantages and energy saving features of each type of starter mentioned will also be discussed. An analysis of the industrial applications and the demand of these starters in Malaysia are also made and to finally conclude, this paper will also provide a suggestion of which starter is most suitable for an application based on the stated constraints.

The role of proportional-integral (PI) controller and proportional-integral-derivative (PID) controller as a speed controller for a Permanent Magnet Synchronous Motor (PMSM) in high performance drive system is still vital although new control techniques such as vector control theory that is more effective -but complex- is available. However, PI controller is slow in adapting to speed changes, load disturbances and parameters variations without continuous tuning of its gains. Conventional approach to these issues is to tune the gains manually by observing the output of the system. The tuning must be made on-line and automatic in order to avoid tedious task in manual control. Hence, an on-line self-tuning scheme using fuzzy logic controller (FLC) is proposed in this paper. The performance of the developed proposed controller is tested through a wide range of speeds as well as with load and parameters variations through simulation using MATLAB/SIMULINK. It is found that the proposed 25 rules FLC with adaptive input and output scaling factors enhances the performance of the system especially at high load inertia. The simulation results show that the developed controller can well adapt to speed changes as well as sudden speed reduction besides fast recovery from load torque and parameters variation and these show remarkable improvement compared to conventional PI controller performance.

This paper addresses some of the potential benefits of using fuzzy logic controllers to control an inverted pendulum system. The stages of the development of a fuzzy logic controller using a four input Takagi-Sugeno fuzzy model were presented. The main idea of this paper is to implement and optimize fuzzy logic control algorithms in order to balance the inverted pendulum and at the same time reducing the computational time of the controller. In this work, the inverted pendulum system was modeled and constructed using Simulink and the performance of the proposed fuzzy logic controller is compared to the more commonly used PID controller through simulations using Matlab. Simulation results show that the fuzzy logic controllers are far more superior compared to PID controllers in terms of overshoot, settling time and response to parameter changes.

This paper investigates new form of a hybrid model reference adaptive speed control (HMRASC) for vector controlled permanent magnet synchronous motor (PMSM) drive. In the proposed scheme, a direct fuzzy logic controller (FLC) is employed as the main controller, and model reference based proportional integral (PI) controller as the adaptation controller. The design and optimization of the FLC and the adaptation mechanism are presented. The efficiency and performance of the HMRASC is examined, by simulation at different operating conditions. The operating conditions studied include various step speed commands from standstill with nominal and changes in motor parameters and load torque. The results obtained are evaluated and compared with direct FLC without the adaptation mechanism. The results achieved show the superior of HMRASC over direct FLC especially for load disturbances and load inertia variations

This paper presents a dynamic induction motor (IM) model which incorporates all the power losses. The presented module is entirely built in Simulink to investigate the effect of varying the applied voltage and frequency on IM efficiency for different load applications. The model includes the power losses such as copper losses, core losses, stray load and mechanical. The accurate determination of induction motor efficiency depends on the estimation of all above mentioned power losses which are modeled and presented in this paper. The effect of variation in applied voltage and frequency on induction motor efficiency is investigated at various load conditions and the results are tabulated and evaluated accordingly. The obtained results show that the efficiency of the IM is significantly affected by the voltage and frequency levels especially at low load. Therefore matching the right applied voltage and frequency to the motor terminal based on the load condition will reduce the motor losses and hence increase its efficiency.