Effect of water on electrical properties of Refined, Bleached, and Deodorized Palm Oil (RBDPO) as electrical insulating material

This paper describes the properties of refined, bleached, deodorized palm oil (RBDPO) as having the potential to be used as insulating liquid. There are several important properties such as electrical breakdown, dielectric dissipation factor, specific gravity, flash point, viscosity and pour point of RBDPO that was measured and compared to commercial mineral oil which is largely in current use as insulating liquid in power transformers. Experimental results of the electrical properties revealed that the average breakdown voltage of the RBDPO sample, without the addition of water at room temperature, is 13.368 kV. The result also revealed that due to effect of water, the breakdown voltage is lower than that of commercial mineral oil (Hyrax). However, the flash point and the pour point of RBDPO is very high compared to mineral oil thus giving it advantageous possibility to be used safely as insulating liquid. The results showed that RBDPO is greatly influenced by water, causing the breakdown voltage to decrease and the dissipation factor to increase; this is attributable to the high amounts of dissolved water

Analysis and solutions of power harmonics in medium voltage distribution networks

The transition toward more sustainable energy systems is driven mainly by greenhouse gas emissions reduction schemes and the growing demand for energy worldwide. Consequently, more Distributed Energy Resources (DER) based power sources and their enabling technologies such as Medium Voltage Direct Current (MVDC) systems are being integrated into the existing distribution networksto help meet such challenges. However, due to the presence of the Power Electronics (PE) based power converters interfacing these systems with the main power network, concerns related to power harmonics in today’s distribution networks must be addressed. To investigate the severity of power harmonics in the distribution networks with the presence of the MVDC converters, a detailed model of an MVDC converter including the switching behaviour of the semiconductor devices with a suitable control system and an interleaved Pulse-width Modulation (PWM) scheme was developed in this study. The key finding is that the proposed harmonic mitigation technique, the interleaved SPWM technique, has significantly reduced the Total Harmonic Distortion (THD) to 2% at the rated system capacity with no significant even-order harmonic components. The real data obtained from the power network of Albaha was also modelled and simulated in the frequency domain using the established harmonic models of the power system components to conductthe harmonic propagations study of the MVDC converter into the AC network. The MVDC converter harmonic performance in the Albaha power system revealed that the THDs at different voltage levels comply with the standard limits. Moreover, applications of Artificial Intelligence (AI), especially the optimization algorithms for power harmonic solutions have received considerable attention over recent years. Thus, in this research, the recently developed Manta Ray Foraging Optimization (MRFO) algorithm has been implemented for the optimal parameters design of a high-pass Passive Power Filter (PPF). An analytical harmonic analysis approach based on the Monte Carlo Simulation (MCS) was also proposed for PPF harmonic performance evaluation including uncertainties at the power network level. For the superiority validation of the MRFO algorithm, different optimizersthat have quite similar hunting and modelling strategies have been adopted. The MRFO algorithm has shown better solution-finding capability but relatively higher computational effort. By including uncertainties at the power network level, the harmonic performance of the optimally designed PPF proposed by the MRFO algorithm was investigated using a proposed MCS-based method, which has shown the significance of the PPF in terms of voltage distortions, system performance parameters, and the network’s hosting capacity for more renewable systems. The results imply that the optimally designed PPF can effectively attenuate the high-order harmonics and improved the system performance parameters over different operating conditions to continually comply with the standard limits. The proposed MCS method showed that the optimally designed PPF reduced the voltage and current distortions by roughly 54% and 30%, respectively, and improved the network hosting capacity by 10% for the worst-case scenario.Furthermore, DER-based power sources are predicted to cause significant harmonic distortions in today’s power networks due to the utilisation of power conversion systems, which are widely recognized as harmonic sources. Identifying the actual contribution of an offending harmonic source can be a challenging task, especially with multiple harmonic sources connected, changes in the system’s characteristic impedance, and the intermittent nature of renewable resources. Hence, a method based on an Artificial Neural Network (ANN) system including the location-specific data was proposed in this thesis to estimate the actual harmonic distortions of a harmonic source. The proposed method would help model the admittance of the harmonic source under the estimation, capture its harmonic performance over different operating conditions, and provide accurate harmonic distortions estimations. For this purpose, a simple power system was modelled and simulated, and the harmonic performance of a solar Photovoltaics (PV) system was used to train the ANN system and improve its prediction performance. Additionally, the expert ANN-based harmonic distortion estimator was validated in the IEEE 34-bus test feeder with different established harmonic sources, and it has estimated the individual harmonic components with a maximum error of less than 10% and a maximum median of 5.4

Development of Multiport Single Stage Bidirectional Converter for Photovoltaic and Energy Storage Integration

The energy market is on the verge of a paradigm shift as the emergence of renewable energy sources over traditional fossil fuel based energy supply has started to become cost competitive and viable. Unfortunately, most of the attractive renewable sources come with inherent challenges such as: intermittency and unreliability. This is problematic for today\u27s stable, day ahead market based power system. Fortunately, it is well established that energy storage devices can compensate for renewable sources shortcomings. This makes the integration of energy storage with the renewable energy sources, one of the biggest challenges of modern distributed generation solution. This work discusses, the current state of the art of power conversion systems that integrate photovoltaic and battery energy storage systems. It is established that the control of bidirectional power flow to the energy storage device can be improved by optimizing its modulation and control. Traditional multistage conversion systems offers the required power delivery options, but suffers from a rigid power management system, reduced efficiency and increased cost. To solve this problem, a novel three port converter was developed which allows bidirectional power flow between the battery and the load, and unidirectional power flow from the photovoltaic port. The individual two-port portions of the three port converter were optimized in terms of modulation scheme. This leads to optimization of the proposed converter, for all possible power flow modes. In the second stage of the project, the three port converter was improved both in terms of cost and efficiency by proposing an improved topology. The improved three port converter has reduced functionality but is a perfect fit for the targeted microinverter application. The overall control system was designed to achieve improved reference tracking for power management and output AC voltage control. The bidirectional converter and both the proposed three port converters were analyzed theoretically. Finally, experimental prototypes were built to verify their performance

Advanced Modeling and Research in Hybrid Microgrid Control and Optimization

This book presents the latest solutions in fuel cell (FC) and renewable energy implementation in mobile and stationary applications. The implementation of advanced energy management and optimization strategies are detailed for fuel cell and renewable microgrids, and for the multi-FC stack architecture of FC/electric vehicles to enhance the reliability of these systems and to reduce the costs related to energy production and maintenance. Cyber-security methods based on blockchain technology to increase the resilience of FC renewable hybrid microgrids are also presented. Therefore, this book is for all readers interested in these challenging directions of research

Engineering planetary lasers for interstellar communication

Transmitting large amounts of data efficiently among neighboring stars will vitally support any eventual contact with extrasolar intelligence, whether alien or human. Laser carriers are particularly suitable for high-quality, targeted links. Space laser transmitter systems designed by this work, based on both demonstrated and imminent advanced space technology, could achieve reliable data transfer rates as high as 1 kb/s to matched receivers as far away as 25 pc, a distance including over 700 approximately solar-type stars. The centerpiece of this demonstration study is a fleet of automated spacecraft incorporating adaptive neural-net optical processing active structures, nuclear electric power plants, annular momentum control devices, and ion propulsion. Together the craft sustain, condition, modulate, and direct to stellar targets an infrared laser beam extracted from the natural mesospheric, solar-pumped, stimulated CO2 emission recently discovered at Venus. For a culture already supported by mature interplanetary industry, the cost of building planetary or high-power space laser systems for interstellar communication would be marginal, making such projects relevant for the next human century. Links using high-power lasers might support data transfer rates as high as optical frequencies could ever allow. A nanotechnological society such as we might become would inevitably use 10 to the 20th power b/yr transmission to promote its own evolutionary expansion out of the galaxy

Advances and Technologies in High Voltage Power Systems Operation, Control, Protection and Security

The electrical demands in several countries around the world are increasing due to the huge energy requirements of prosperous economies and the human activities of modern life. In order to economically transfer electrical powers from the generation side to the demand side, these powers need to be transferred at high-voltage levels through suitable transmission systems and power substations. To this end, high-voltage transmission systems and power substations are in demand. Actually, they are at the heart of interconnected power systems, in which any faults might lead to unsuitable consequences, abnormal operation situations, security issues, and even power cuts and blackouts. In order to cope with the ever-increasing operation and control complexity and security in interconnected high-voltage power systems, new architectures, concepts, algorithms, and procedures are essential. This book aims to encourage researchers to address the technical issues and research gaps in high-voltage transmission systems and power substations in modern energy systems

Parametric analysis of microwave and laser systems for communication and tracking Quarterly report, 6 Mar. - 6 Jun. 1966

Parametric analysis of microwave and laser systems for communication and tracking - updated reference data for advanced space communication and tracking system