Energy Management System Designed for the Interconnected or Islanded Operation of a Microgrid Using LabVIEW Software

Integration of distributed generation units and other users within the low and medium voltage distribution grid induces a variety of problems related to the management and control of microgrids. These aspects can be solved by using significantly different Energy Management Systems for the operation of microgrids, comparing to those applied to conventional power systems. The main objective of the Energy Management System is to ensure the rational use of energy, while minimizing its costs. The secondary objectives relate to increasing energy efficiency and reducing energy consumption, but especially to assuring the power facilities security. Moreover, the management of power systems to which renewable sources are connected is one of the main concerns of Distribution System Operators in order to ensure the safe operation, security of power supply, and the operation optimization from the economic side. The chapter regards the LabVIEW design and testing of an Energy Management System for the interconnected or islanded operation of a microgrid to the electric public grid. Furthermore, the chapter leads to the microgrids development in terms of operation and efficiency by achieving an Energy Management System designed for a small mixed microgrid with separate AC and DC rings bidirectionally interconnected by static converters

Assessment of the Main Requirements and Characteristics Related to the Implementation of a Residential DC Microgrid

A generic DC microgrid consists of a number of electric generators with static converters as interface modules, electric loads (to be connected either at DC or AC with inverter modules), as well as connection (by transformer and conversion modules) to the electric distribution network. The chapter envisages the state of the art on DC electric power distribution systems by tapping both high- and low-voltage direct current technologies and leading to the current development prospects. Moreover, a study on the existing standards applicable to DC distribution systems is achieved. The chapter leads to the establishment of the main technical requirements and characteristics suitable to the implementation of a residential DC microgrid. Also, electrical diagrams of the foreseen solutions and users’ recommendations and challenges are suggested by the paper

Increasing the energy conversion efficiency for shrouded hydrokinetic turbines using experimental analysis on a scale model

The objective of the paper is to study the influence of certain shroud types suitable for horizontal axis hydrokinetic turbines using experimental testing in order to increase the energy conversion efficiency. The scale model of the shrouded hydrokinetic turbine is tested on a dedicated experimental bench for axial hydraulic turbine models. Two types of shrouds were tested in order to be compared: convergent shroud and divergent shroud. The rotor and shroud were made using 3D printer technology and were tested at a water velocity of 0.9 m/s on the closed-circuit testing bench. The testing facility allows the determination of the power extracted for each shroud at five distinct positions. Thus, the rotor can be moved within the shroud from inlet to outlet in order to establish the proper operating position. The mechanical power is measured using a torque transducer and an electromagnetic particle brake. The testing results will be analysed based on the variation of power curves obtained for different shroud types and operating positions. The optimum design and the best operating position will be recommended by comparing the testing result with the data collected from the bare turbine using the same rotor placed directly in free flow

Efficient energy use and storage practices within residential facilities for compliance with the nZEB criteria

Solar energy, today, is the leader in renewable energy and the world's increasing new energy source. In 2016, for the first time, newly installed photovoltaic capacity has increased by more than 50%, exceeding the new coal-fired power stations capacity established worldwide. At the beginning of the year, the European Parliament agreed the target that 35% renewable sources by 2030. Studies show that by 2050 approximately 45% of all the households in the EU could produce their own renewable energy and more than a third of them could be part of a renewable energy cooperative, despite the worries of the distribution companies. Furthermore, the EPBD directive (EU) - Energy Performance of Buildings pushes towards new and more performing buildings - nearly zero energy buildings (nZEB) - where energy efficiency and energy flexibility are essential to achieve the required performance targets. Nearly zero-energy buildings (NZEBs) have very high energy performance and could be achieved through the integration of renewable and decentralized energy sources, continuous grid optimization and the inclusion of increasing numbers of consumers becoming producers, so called prosumers. So far, the photovoltaic system is the single technology that can combine data from utility networks with household consumption and therefore should be considered a starting point for streamlining the electricity consumption and production which will be imposed by strict regulations

Analysis of a low-voltage operating microgrid located in a residential area

The paper aims at providing the analysis of domestic energy generation and consumption within residential areas. The topic of this study is twofold: theoretical and experimental by addressing aspects related to the operation of a microgrid connected to the low-voltage distribution grid. In order to achieve the power quality analysis for various scenarios, an appropriate testing stand was developed by using the Chauvin Arnoux CA 8435 analyser. There is envisaged the modelling and design of a mixed microgrid characterized by two line sections established by three main energy consumption nodes. There have been integrated several connection points related to the distributed generation sources and to the photovoltaic power plants, respectively, and also several supply points for the household end-users. 13 operation scenarios have been developed and recorded by analysing the voltage variation within the microgrid. Furthermore, the paper envisages the stabilization impact of the microgrid voltage variation in the presence of distributed generation sources

Efficient energy use and storage practices within residential facilities for compliance with the nZEB criteria

Solar energy, today, is the leader in renewable energy and the world's increasing new energy source. In 2016, for the first time, newly installed photovoltaic capacity has increased by more than 50%, exceeding the new coal-fired power stations capacity established worldwide. At the beginning of the year, the European Parliament agreed the target that 35% renewable sources by 2030. Studies show that by 2050 approximately 45% of all the households in the EU could produce their own renewable energy and more than a third of them could be part of a renewable energy cooperative, despite the worries of the distribution companies. Furthermore, the EPBD directive (EU) - Energy Performance of Buildings pushes towards new and more performing buildings - nearly zero energy buildings (nZEB) - where energy efficiency and energy flexibility are essential to achieve the required performance targets. Nearly zero-energy buildings (NZEBs) have very high energy performance and could be achieved through the integration of renewable and decentralized energy sources, continuous grid optimization and the inclusion of increasing numbers of consumers becoming producers, so called prosumers. So far, the photovoltaic system is the single technology that can combine data from utility networks with household consumption and therefore should be considered a starting point for streamlining the electricity consumption and production which will be imposed by strict regulations

Increasing the energy conversion efficiency for shrouded hydrokinetic turbines using experimental analysis on a scale model

The objective of the paper is to study the influence of certain shroud types suitable for horizontal axis hydrokinetic turbines using experimental testing in order to increase the energy conversion efficiency. The scale model of the shrouded hydrokinetic turbine is tested on a dedicated experimental bench for axial hydraulic turbine models. Two types of shrouds were tested in order to be compared: convergent shroud and divergent shroud. The rotor and shroud were made using 3D printer technology and were tested at a water velocity of 0.9 m/s on the closed-circuit testing bench. The testing facility allows the determination of the power extracted for each shroud at five distinct positions. Thus, the rotor can be moved within the shroud from inlet to outlet in order to establish the proper operating position. The mechanical power is measured using a torque transducer and an electromagnetic particle brake. The testing results will be analysed based on the variation of power curves obtained for different shroud types and operating positions. The optimum design and the best operating position will be recommended by comparing the testing result with the data collected from the bare turbine using the same rotor placed directly in free flow

Analysis of a low-voltage operating microgrid located in a residential area

The paper aims at providing the analysis of domestic energy generation and consumption within residential areas. The topic of this study is twofold: theoretical and experimental by addressing aspects related to the operation of a microgrid connected to the low-voltage distribution grid. In order to achieve the power quality analysis for various scenarios, an appropriate testing stand was developed by using the Chauvin Arnoux CA 8435 analyser. There is envisaged the modelling and design of a mixed microgrid characterized by two line sections established by three main energy consumption nodes. There have been integrated several connection points related to the distributed generation sources and to the photovoltaic power plants, respectively, and also several supply points for the household end-users. 13 operation scenarios have been developed and recorded by analysing the voltage variation within the microgrid. Furthermore, the paper envisages the stabilization impact of the microgrid voltage variation in the presence of distributed generation sources

Experimental Analysis of a Fish Guidance System for a River Water Intake

This paper describes the experimental study of a behavioural barrier consisting of a bubble curtain placed near an ecological river water intake, aiming to assess the bubble curtain’s influence on the velocity field of water flowing in the water intake proximity. The scientific novelty is given by the water intake solution operating in tandem with the dedicated bubble curtain generator used for avoiding fish entrapment. The water intake solution used in the present research is based on a run-of-river intake without a dam in the riverbed, maintaining the mountain rivers longitudinal connectivity. An experimental setup was designed and built to study the behavioural barrier for ecological water intakes in different operating conditions. Thus, tests were performed for two water velocities (0.33 m/s and 0.535 m/s) in the experimental setup, two water depths (92 mm and 119 mm) and two air flow rates (10.5 LPM and 15 LPM). The results were compared with the case when no air is injected through the bubble curtain generator. The assessment of the bubble curtain influence on the water flow inside the channel was made by measuring and analysing the velocity variation in vertical and horizontal direction. The results showed a significant velocity gradient in the bubble curtain proximity, which can contribute to influencing the behaviour of the fish by deterring them from the water intake area

Experimental Analysis of a Fish Guidance System for a River Water Intake

This paper describes the experimental study of a behavioural barrier consisting of a bubble curtain placed near an ecological river water intake, aiming to assess the bubble curtain’s influence on the velocity field of water flowing in the water intake proximity. The scientific novelty is given by the water intake solution operating in tandem with the dedicated bubble curtain generator used for avoiding fish entrapment. The water intake solution used in the present research is based on a run-of-river intake without a dam in the riverbed, maintaining the mountain rivers longitudinal connectivity. An experimental setup was designed and built to study the behavioural barrier for ecological water intakes in different operating conditions. Thus, tests were performed for two water velocities (0.33 m/s and 0.535 m/s) in the experimental setup, two water depths (92 mm and 119 mm) and two air flow rates (10.5 LPM and 15 LPM). The results were compared with the case when no air is injected through the bubble curtain generator. The assessment of the bubble curtain influence on the water flow inside the channel was made by measuring and analysing the velocity variation in vertical and horizontal direction. The results showed a significant velocity gradient in the bubble curtain proximity, which can contribute to influencing the behaviour of the fish by deterring them from the water intake area