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Utility Grid with Hybrid Energy System
Published in Yatish T. Shah, Hybrid Power, 2021
There are a few key differences between the equipment needed for grid-tied, off-grid, and hybrid solar systems. Standard grid-tied solar systems rely on (a) grid-tie inverter (GTI) or micro-inverters: a solar inverter regulates the voltage and current received from solar panels. Direct current (DC) from solar panels is converted into alternating current (AC), which is the type of current that is utilized by the majority of electrical appliances. In addition to this, grid-tie inverters, also known as grid-interactive or synchronous inverters, synchronize the phase and frequency of the current to fit the utility grid (nominally 60 Hz). The output voltage is also adjusted slightly higher than the grid voltage in order for excess electricity to flow outward to the grid. Micro-inverters go on the back of each solar panel, as opposed to one central inverter that typically takes on the entire solar array. There has recently been a lot of debate on whether micro-inverters are better than central (string) inverters. Micro-inverters are certainly more expensive but in many cases yield higher efficiency rates. (b) Power meter: power meter, often called a net meter or a two-way meter, is capable of measuring power going in both directions, from the grid to the house and vice versa.
Inverter Circuit Coordination with a Distributed Photovoltaic Grid Power Transformer
Published in Hemchandra Madhusudan Shertukde, Distributed Photovoltaic Grid Transformers, 2017
Hemchandra Madhusudan Shertukde
Grid-tie inverters are also designed to quickly disconnect from the grid if the utility grid goes down. This is a NEC requirement that ensures that in the event of a blackout, the GTI will shut down to prevent the energy it produces from harming any line workers who are sent to fix the power grid.
A grid-tie PV inverter with the ability to improve power quality under unbalanced and distorted source voltage conditions
Published in Journal of the Chinese Institute of Engineers, 2018
Hadi Afkar, Mohammad Ali Shamsinejad, Mahmoud Ebadian
In a large number of studies performed so far, it has been shown that in addition to connecting renewable energy sources to the grid, distributed generation sources are capable of improving power systems stability to some extent. In distributed generation systems the grid-tie inverters are the main interface for connecting renewable energy sources and energy storage devices to the grid (Blaabjerg, Chen, and Kjaer 2004). To have cost-effective grid-tie inverters in DGs, multi-functional grid-tie inverters are suggested (Zeng et al. 2013, 2015). Electronic power converters can not only serve as an interface to the grid but they can also have the potential to alleviate problems with power quality.
Technical and economic feasibility assessment for a solar PV mini-grid for Matekenya village
Published in Cogent Engineering, 2022
Peter Maliro, Bakary Diarra, Ravi Samikannu
Solar PV systems are made up of various components. The components of a Solar PV system include solar panels, charge regulators, batteries, inverter, and protection devices. Solar is used to convert solar radiation to electricity. These are connected in parallel or series to achieve the voltage or current required by the system. Batteries are used to store energy in the system by converting the electrical energy to chemical energy and converting it back to electrical energy (Mussi et al., 2021; Wu et al., 2022). They are classified as primary batteries and secondary batteries. Primary batteries are non-rechargeable while secondary batteries are rechargeable. Types of secondary batteries include lead-acid batteries, lithium-ion batteries, nickel-cadmium batteries, nickel-metal hydride batteries, lithium-ion batteries, zinc-air batteries, and lithium polymer batteries (Price, 2018). Charge controllers are devices that are used to control overcharging and over-discharging of the batteries. They disconnect the battery from the power source when the voltage level reaches the design limit to prevent batteries from overcharging. To protect from over-discharging the charge controller disconnects the load from the battery when the voltages are below the minimum set by manufacturers. Types of charge controllers include shut type charge controllers, series charge controllers, Pulse width Modulation charge controllers (PWM), and Maximum Power Point Tracking charge controllers (MPPT; Manik et al., 2017). PWM charge controllers operate by switching transistor frequency with various modulated widths while maintaining constant voltage (Vergara et al., 2022,,). MPPT charge controllers use DC-DC converters to convert voltage from the solar array to suit the battery voltage (Bhukya and Shanmugasundaram. 2021). Inverters convert direct current to alternating current. Inverters are classified based on input, output power rating, and application (Dogga & Pathak, 2019, Ketjoy et al., 2021; Parthasarathy & Vijayaraj, 2020; 2022,Vergara et al., 2021). The input-based classification includes voltage-fed inverters, current-fed inverters, and DC-link inverters. Inverter classification based on output includes pure sine wave inverters, square wave inverters, and quasi square wave inverters. Inverters classified based on output power rating include single-phase inverters and three-phase inverters. Inverters classified based on the application include grid-tie inverters, standalone inverters, and hybrid inverters. Protection devices are used to protect against accidents associated with the system or damage to any component. These include fuses, disconnects, and circuit breakers.