Dc Microgrid And Control System Lecture 2 PDF

DC Microgrid and Control System Concept of Microgrids Lecture 02 Dr. Avik Bhattacharya Assistant Professor Room No. 227, Department of Electrical Engineering Indian Institute of Technology Roorkee Phone: 01332285375...

DC Microgrid and Control System Concept of Microgrids Lecture 02 Dr. Avik Bhattacharya Assistant Professor Room No. 227, Department of Electrical Engineering Indian Institute of Technology Roorkee Phone: 01332285375 Email: [email protected] 1  Contents Introduction Microgrid Structure Benefits of Microgrids Applications of microgrid Microgrid Components DERs in Microgrid Power Electronics in microgrid Classification of microgrids 2  Introduction  The emergence of smaller generating systems such as PV, wind, fuel cell, microturbines have opened new opportunities for on-site distributed power generation.  Economical challenges, technological advancements and environmental impacts are now demanding this distributed generation (DG).  The DGs have received much attentions because it reduce the burden from the conventional power system. 3  Introduction (cont…)  To overcome the irregular behavior and increasing penetration of distributed generation microgrid was introduced.  The microgrid looks promising for future aspects. It has the ability to respond to change in the load, while decreasing the feeder losses and improving local reliability.  Microgrids are low voltage networks or distributed energy system that provides heat and power to a particular area by employing generators and loads. 4  Microgrid Architecture  The basic architecture of Microgrid system is shown in Fig. 1.  The comprises of:  Micro generation  Energy storage system  Load and control system  Power electronic interfacing converter Fig.1:Structures of Microgrid 5  Microgrid Architecture (cont…) The microgrid structure assumes an aggregation of loads and microsources operating as a single system providing both power and heat. The majority of the microsources are power electronic based to provide the required flexibility to ensure controlled operation as a single aggregated system. This control flexibility allows the microgrid to the utility grid as a single controlled unit, have plug-and-play simplicity for each microsources, and meet the customers’ local needs. These needs include increased local reliability and security. 6  Benefits of Microgrid Enables Grid Modernization Enables integration of multiple Smart Grid technologies Enhance the integration of Distributed and Renewable Energy Sources Facilities integration of combined heat and power (CHP) Promotes energy efficiency and reduces losses by generation near demand Potential to reduce large capital investments by meeting increased consumption with locally generated power. Potential to reduce peak load 7  Benefits of Microgrid (cont…)  Encourages third-party investment in the local grid and power supply Meets End User Needs Ensure energy supply for critical loads Power quality and reliability controlled locally Promotes demand-side management and load leveling Promotes community energy independence and allows for community involvement in electricity supply Designed to meet local needs & increase customer participation 8  Application of Microgrid  Microgrids can meet the needs of a wide range of applications in commercial, industrial, and institutional.  Larger Microgrid applications include communities ranging from neighborhoods to small towns to military bases.  Another largely untapped application is the “off grid” area of the world where one billion-plus people live without regular access to electricity. 9  Application of Microgrid (Cont…)  The Microgrids structure makes it a viable platform for large entities to reduce energy costs and generate revenue through the sale of energy during periods of peak demand.  Additionally, microgrids can efficiently and effectively provide "off-grid" areas with regular access to electricity as well as "keep the lights on" in times of crisis for critical applications like a hospital. 10  Components of Microgrid  The Microgrid system generally consists of four parts: Distribution system DG sources Energy storage (ES) Controllers and Loads 11  Distributed generation resources (DER)  Distributed generation (DG) technologies applicable for Microgrids may include a range of technologies:  Wind power system  Solar photovoltaic (PV) system  Small Hydro power system  Geothermal energy  Biogas, ocean energy  Single-phase and three-phase induction generators and synchronous generators driven by IC engines 12  Power Electronics (PEs) in Microgrid Application  LED lighting  Interfaces for renewable energy systems such as wind and solar photovoltaic (PV), electric power stage in batteries, high- efficiency electrical drives used in industry and in electric vehicle, and high-voltage DC systems.  PE has therefore become an important part of modern microgrids.  Not only are many storage and distributed generation system connected to the microgrid via PE converters, many of the modern loads use some sort of power conversion to ensure high- efficiency and high-performance operation. 13  Classification of Microgrids  Microgrids can be established based on the following:  Capacity  Location  Type of distributed resources (DR) to suit the situation  Microgrids can be classified as :  By function demand  By capacity  AC/DC type  By function demand  Simple microgrid  Multi-DG Microgrid  Utility Microgrid 14  Classification of Microgrids by capacity Type Capacity (MW) Simple microgrid 20 Independent microgrid Depending on loads on an island, a mountainous area or a village 15  Based on capacity Simple Microgrid  A simple microgrid has a capacity below 2 MW and is intended for independent facilities and institutes with multiple types of loads and of a small area, such as a hospital or school. Corporate microgrid  A corporate microgrid has a capacity of 2–5 MW, and comprises combined cooling, heating and power (CCHP) of varying sizes and some small household loads, generally no commercial or industrial loads. Feeder area microgrid  A feeder area microgrid has a capacity of 5–20 MW and comprises CCHPs of varying sizes and some large commercial and industrial loads. 16  Based on Capacity (Cont…) Substation area microgrid  A substation area microgrid has a capacity above 20 MW and generally comprises common CCHPs and all nearby loads (including household, commercial, and industrial loads).  The aforementioned microgrids are connected to common grids and therefore are collectively called grid-connected microgrid. Independent microgrid  An independent microgrid is mainly intended for remote off-grid areas such as an island, a mountainous area, or a village, and the distribution system of the main grid uses a diesel generator or other small units to meet the power demand of such areas. 17  By AC/DC type Microgrids are classified into DC microgrid, AC microgrid, and AC/DC hybrid microgrid based on voltage and current types DC Microgrid In DC microgrid, DG, ES, and DC load are connected to a DC bus via a converter and the DC bus is connected to AC loads via an inverter to supply both DC and AC loads as shown in Fig.2. Fig.2:Structure of a DC microgrid 18  AC Microgrid In AC microgrid, the distribution network is connected to the AC bus via circuit breaker and the AC bus controls the microgrids operation system through the circuit breaker at the PCC. Fig.3: shows the structure of an AC microgrid, in which DG and ES are connected to the AC bus via inverter. Fig.3:Structure of AC microgrid 19  AC/DC Microgrid An AC/DC hybrid microgrid is a microgrid consisting of an AC bus and a DC bus. Fig.4: shows the structure of such a microgrid, in which the AC bus and DC bus allow for direct supply to AC loads and DC loads. Fig.4:Structure of AC microgrid 20 Thank you 21