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With the increasing number of solar PV systems, the future grid-connected converters should provide a full range of services. Such requirements make the operators of the distribution system modify the current grid codes to ensure the security of the power grid and enhance the Low Voltage Ride-Through (LVRT) capability of renewable energy resources (RER). Nowadays, in many countries, the smart grid is standardized, and thus, the development of control strategies for a grid-connected PV system is crucial, particularly with the high level of PV penetration. Initially, the paper reviews the grid codes for LVRT capability of grid-connected solar PV systems. Furthermore, the paper proposes an improved protection control strategy for the DC link of grid-connected PV system with reactive power support to enhance the LVRT during grid faults. The test results presented in this paper have vindicated the effectiveness of the proposed approach. Unlabelled Image • The PV system can comply with the new grid codes using the proposed approach with optimal selection of crowbar resistor. • Application of the harmonized grid codes as benchmark to ensure the security of grid-connected PV system during fault. • A developed DC link crowbar protection with a power control scheme can facilitate the task of providing power support. • The developed approach enables the solar PV system to stay longer connected than the specified period in the new grid codes. [ABSTRACT FROM AUTHOR]

The Smart Grid (SG) is an emerging concept, which is in a testing phase in many countries. It is a relatively new perception that integrates electricity and communication on power system networks, which enable SG applications, mainly for the use of Renewable Energy Sources (RES). This paper presents a review of the existing studies on SG systems, the use of SG technologies and the modeling techniques for SG available in the literature. Furthermore, the paper focuses on SG features when connected at a distribution grid and its active distribution management capability. It also identifies the current practice as provided in technical standards and potential industry investments that can facilitate a pathway towards SG development in Australia. The paper also has highlighted the possible areas of research that would be required to implement practical SG facilities. [ABSTRACT FROM AUTHOR]

Abstract: Pico hydro is a term used to distinguish very small-scale hydropower with a maximum electrical output of five kilowatts (5kW). It is a good technique of providing electricity to the off-grid remote and isolated regions that suffer energy deficit. Typical pico hydro generator is designed and supported by electrical converting system, batteries and safety equipment so that it can be installed at the residential water pipeline. In pico hydro generation, the environmental impact is negligible since large dams are not involved, and the schemes can be managed and maintained by the consumer. This paper is reviewing the application of hydro generation and particularly focusing on the implementation of pico hydro generation system in University Malaysia Pahang (UMP) Campus-Pekan. This system was designed and simulated using the Matalb simulink blocks. The pico hydro generator has been tested in a real application with a pelton turbine design which utilizes a high pressure of water flowing from the main tank into the faculties. The speed of the turbine and alternator depend on the pressure of the water. In this work, a 1.05kW alternator is used to charge the battery and the DC power output from a battery is converted into 220V, 50Hz. [Copyright &y& Elsevier]

Abstract: One of the most popular issues in the future power distribution is the quality improvement of microgrid and the development of smart grid (SG). Many applications operating at the microgrid level can be considered as smart grid functions. This paper proposes the application of Fuzzy Logic (FL) technique within microgrid energy system based on the most modern power conditioning equipment devices such as Unified Power Quality Conditioner (UPQC). This technique is working together with the microgrid to track the disturbance of the smart grid and improve the quality of the system with a high flexibility. Furthermore, a control methodology developed based on a simulation technique to maintain the output voltage of the microgrid. Finally, experimental results show the high performance of the proposed Fuzzy Logic controller (FLC) compare to the classical proportional integration (PI). [Copyright &y& Elsevier]

Abstract: This paper proposes the use of a PV–wind–diesel generator hybrid system in order to determine the optimal configuration of renewable energy in Malaysia and to compare the production cost of solar and wind power with its annual yield relevant to different regions in Malaysia namely, Johor, Sarawak, Penang and Selangor. The configuration of optimal hybrid system is selected based on the best components and sizing with appropriate operating strategy to provide a cheap, efficient, reliable and cost-effective system. The various renewable energy sources and their applicability in terms of cost and performance are analyzed. Moreover, the annual yield and cost of energy production of solar and wind energy are evaluated. The Simulations were carried out using the HOMER program based on data obtained from the Malaysian Meteorological Centre. Results show that, for Malaysia, a PV–diesel generator hybrid system is the most suitable solution in terms of economic performance and pollution. However, the cost of production of solar and wind energy proved to be cheaper and more environmentally friendly than the energy produced from diesel generators. [ABSTRACT FROM AUTHOR]

Abstract: Vulnerability assessment and control of a power system is important to power utilities due to the blackouts in recent years in many countries which indicate that power systems today are vulnerable when exposed to unforeseen catastrophic contingencies. A fast and accurate technique to assess the level of system strength or weakness is some of the essential requirements for maintaining security of modern power systems, particularly in competitive energy markets. This paper presents intelligent artificial techniques for vulnerability assessment of Malaysian power system and recommends preventive control measures. Accurate techniques for vulnerability assessment and control of power systems are developed. In vulnerability assessment, power system loss index is used as a vulnerability parameter, neural network weight extraction is employed as the feature extraction method and the generalized regression neural network is used to predict vulnerability of a power system. As for vulnerability control, load shedding is considered by using the neuro-fuzzy technique. Finally, the paper presents and discusses the results from this research with recommendations. [Copyright &y& Elsevier]

Abstract: Vulnerability control is becoming an essential requirement for security of power systems in the new utility environment. It is a difficult task for system operator who under economic pressure may be reluctant to take preventive action against harmful contingencies in order to guarantee providing continued service. For power systems which are operated closer to their stability limits, it is desirable to use load shedding as a form of vulnerability control strategy. This paper presents a neuro-fuzzy approach for determining the amount of load to be shed in order to avoid a cascading outage. The objective is to develop fast and accurate load shedding technique to control the vulnerability of power systems by means of using a neuro-fuzzy controller. A case study is performed on the IEEE 300-bus test system so as to validate the performance of neuro-fuzzy controller in determining the amount of load shed. Test results prove that the neuro-fuzzy controller provides accurate and faster vulnerability control action. [Copyright &y& Elsevier]

As distributed renewable energy sources (RES) continue to expand, the necessity arises for more robust coordination approaches and conversion techniques to tackle the challenges introduced by uncertainties in renewable generation. Increasing concerns about energy efficiency and power grid security, such as the significant number of conversion stages for energy production from renewable resources and the bidirectional power flow in the distribution system, have attracted attention to the topic. The presented comprehensive review in this paper discusses the merits and weaknesses of different integration strategies as supported by the literature review. In particular, the focus is placed on the challenges of interconnection and opportunities for direct current (DC) systems. The ultimate objective of this paper is to explore the most important power grid-wide effects due to the expected renewable energy expansion and to gain insights on the availability characteristics of DC microgrids to facilitate their integration with the power grid. The idea behind this is to establish inferences that energy conversion based DC microgrids can be a possible solution to mitigate the negative effect of renewable energy expansion. This is accomplished by systematically reviewing studies on power grid integration as well as providing technical analysis of the resulting outcomes in relation to the general impact of renewable energy production, and then, conducting a comparative study on renewable energy conversion based DC and alternating current (AC) systems. The types of bus topologies and control of DC distribution systems are also intensively reviewed and discussed. Moreover, the protection design considerations, control classifications and standards of DC microgrids are highlighted to explore the future research trends to be undertaken. The review concluded that the impact of interconnection on power grid can be eliminated through the use of intelligent control with advance communication technologies and the implementation of DC microgrids powered by sustainable resources in the distribution system. • Energy production from renewable sources is reviewed by discussing the merits and weaknesses of grid integration. • Renewable energy conversion based DC system is the possible solution to overcome the issues of generation expansion. • The standards of DC microgrids need to be enhanced to ensure the security during different operating conditions. • The review confirms that efficient protective devices of DC systems have not been developed as compared to AC systems. [ABSTRACT FROM AUTHOR]

• Stochastic swarm optimization based regression approach is utilized for energy pricing. • Transient behaviors of techno-economic analysis for renewable resources are assessed. • The optimal hybrid microgrid is affected by fault location and capacity of energy storage. • Deterministic method pinpoints fixed energy cost, making dynamic pricing uncertain. With the development of scattered energy resources in the rural areas of Sarawak (Malaysia), various operational problems due to the unplanned installation of autonomous microgrids become gradually remarkable. To address this concern, the paper proposes an optimal strategy to evaluate the performance of different hybrid microgrid configurations for the Long San Village in Sarawak. A mathematical model is presented for sizing the component of the system to meet the maximum load demand under changing weather conditions and at the lowest possible cost. The developed approach simulates different microgrid models using deterministic and stochastic optimization methods to find the exact dynamic energy price of the selected optimal configuration in the context of system uncertainties. Furthermore, the operational feasibility of the system in terms of reliability and voltage security is studied in addition to economic feasibility with a comparative analysis of the environmental impact. The results show that the optimal configuration with the lowest cost of energy and net present cost can be achieved if the installed solar PV is less than 61 kW with 85 kW h of energy storage and 11 kW of hydro generation, where such system has 55,725 (kg/year) Carbon Dioxide and 330 (kg/year) Nitrogen Oxides. The findings also indicate that the dynamic energy pricing increases to 0.71 $/kWh when the power generation from renewable resources drops to zero. Further, the dynamic analysis shows that in order to reduce the voltage drop during disturbances, it is crucial to carefully install the sources in the buses connected to high energy demand. [ABSTRACT FROM AUTHOR]

Recent interest in the integration of renewable energy sources (RES) into the power grid has raised concerns in synchronization of the various RES. Grid variables such as voltage, phase angle and frequency should be continuously monitored to guarantee correct operation and synchronization of power converters connected to the power grid. Numerous synchronization methods have been presented over the years to address issues such as unbalanced condition and frequency variation. This paper presents a review of past studies on synchronization methods for grid-connected converters together with their control and modeling techniques. Various estimation techniques for phase angle, frequency and harmonic are discussed and examined. Key challenges for a smart and efficient synchronization are briefly overviewed and possible future works are also recommended. A consolidated review is the particular focus of this paper, as is the provision of information on the best method for synchronizing grid-connected converters. [ABSTRACT FROM AUTHOR]