Abstract
Micro grid is widely used in real worlds for advanced forecasting and demand response of renewable energy source, grid integration, and operations. Micro grid consists of conventional and nonconventional energy source such as wind energy, solar energy, biomass energy, hydro power, diesel power, fuel cell, geothermal power, thermal power, etc. Micro grid is a combination of AC power and DC power such as wind, solar, fuel cell, biomass, and Hydro power, which is mostly used in micro grids. Grid can be operated by grid connected mode or islanding modes. Micro grid is classified into traditional micro grids and smart micro grids.
TopIntroduction
Smart grid is the future of power grid in the real world with regards to powers systems planning, operation, design and control (Akshata et al. 2014, SGETP, 2008). Microgrid is also the feature of smart grid. It consists of renewable and non-renewable energy source such as hydro power, solar power, wind power, geothermal, thermal power, biomass, fuel cell, gas storage and many more (Dohn, et al. 2011, IEEE, 2009). Micro grid includes two main systems in it i.e. distributed generator (DG) and distribution storage (DS) (Gonen et al. 2013). Micro grid can be operates either grid connected mode and islanding mode (Mehrizi-Sani et al. 2010). In grid connected mode, micro grid is connected to the utility grid and the power for customer is sufficiently available as compare to islanded mode in which it is disconnected from the grid. This switching between micro grid and main grid is performed to connect and disconnect the micro grid from the main grid for various purposes (Lidula et al.2011, Mehrizi-Sani et al. 2010). Generally micro grid switching for grid connected mode or islanding mode is performed by circuit breaker or protective relay and when circuit breaker or relay is closed it is called grid connected mode, when it is open it is called islanded mode (Alhelou et al., 2019; Makdisie et al., 2018; Alhelou et al., 2018; Alhelou et al., 2016; Haes Alhelou et al., 2019; Njenda et al., 2018). This connection and disconnection is performed at point of common coupling (PCC) (Che et al. 2014). Switch of micro grid can be made in and out by the transmission systems (Kuo et al. 2011). Micro grid is consists of AC power as well as DC power, when say AC power, it is from main grid and when say DC power, it is from solar. In the grid connected mode, Micro grid can supply sufficient power while in islanded mode the power sometimes reached to lower level as per the availability of the resources (Akshata et al. 2014, Mehrizi-Sani et al. 2010). Micro grid can be used to reduce the global warming (Khan et al., 2019; Khan et al., 2018; Khan et al., 2017; Banteywalu et al., 2019; Anteneh et al., 2019; Molla et al., 2019, Molla et al., 2018, Jariso et al. 2018).
Key Terms in this Chapter
Smart Grid: an electricity supply network that uses digital communications technology to detect and react to local changes in usage.
Protective Relay: It is an intelligent electronic devices (IEDs) which receive measured signals from the secondary side of CTs and VTs and detect whether the protected unit is in a stressed condition (based on their type and configuration) or not. A trip signal is sent by protective relays to the circuit breakers to disconnect the faulty components from power system if necessary.
Reliability: A measure of the degree of certainty that the relay, or relay system, will perform correctly.
Fuel Cell: A fuel cell is an electrochemical cell that converts the chemical energy of a fuel (often hydrogen and an oxidizing agent (often oxygen) into electricity through a pair of redox reactions.