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Unlike traditional power grids, smart grids have the advantage of bidirectional power flow and having distributed generations. Distributed generation systems are usually supplied by renewable sources which can cause unpredicted voltage fluctuations as a result of being intermittent. While traditional compensating devices deal with the problem of voltage fluctuation and reduced power quality with a...
The grid connected photovoltaic (PV) system have been modeled and simulated using control algorithm with dedicated PI control for dc link voltage regulation. Generally, the PI controller used for the system is tuned using trial and error method but this method is having manual limitation for the tuning of controller so as to obtain the desired response like as regulating dc link voltage to reference...
In this paper, the most prominent inverter interface control techniques for the grid-connected photovoltaic (PV) systems; the constant-current control (CCC) and constant-power control (CPC) were evaluated based on the dynamics of the inverter local load. A fully controlled 100 kW grid-connected PV distributed generation (DG) with dynamic load is simulated in MATLAB Simiilink. The CCC has one fast...
Electrical distributors in Australia are experiencing high penetration levels of small scale distributed generation, such as solar photovoltaic systems, particularly being installed on houses that are connected to the Low Voltage network. Distributed generation is challenging the traditional operating paradigm and can result in occurrences of voltage rising to the point where it goes above safe limits,...
In this paper two active anti-islanding methods are evaluated and compared according to the ABNT NBR 62116 and IEEE STD 929-2000 standards. These standards specify voltage and frequency trip time settings and trip magnitudes. The first method is the active frequency drift with positive feedback and the second one is the active frequency jump that is based on phase-locked loop perturbation. The latter...
The amount of distributed generators connected to the utility grid has been growing every year. With this in mind, it is necessary to use methods that can detect islanding conditions in a faster way and that do not decrease the quality of the energy provided by the utility grid. This paper focuses on the design and simulation of a single phase grid-tied photovoltaic system using an active frequency...
Mashhad Electric Energy Distribution Company (MEEDC) has designed and implemented the first local micro-grid in Mashhad which is called “MehrSun”. This article presents the performance analysis and result assessment of Mehrsun after working for one year. Different micro-grid elements and the connections with local power network are explained and the level of home automation which is implemented for...
The power conditioning system (PCS) is widely used as a grid connected inverter to keep output constant. A novel power conditioning system (PCS) using a circuit of modular multi-level converter (MMC) construction is investigated. The feature of the system is that output voltage becomes multilevel for low distortion and circuit has an energy storage system such as a battery or an electric double layer...
The number of photovoltaic distributed generators introduced into electricity distribution systems is increasing worldwide. Safety measures must be taken for the correct operation of these new distributed generators so as to prevent uncontrolled and undesired power injections into the grid and possible damages to equipment and personnel. This paper describes an anti-islanding detection method used...
This study evaluated power generation characteristics of sixteen different types of Photovoltaic (PV) systems in “F Solar Research Park”. As a result, the performance ratio of crystalline silicon and CIS PV systems were higher during winter months and decreased in summer whereas amorphous PV systems were reverse seasonal characteristics due to the light induced degradation and annealing effect. This...
Stand-alone photovoltaic systems are still required in locations where electricity is unavailable. They can provide electric energy for pumping systems, lightings, etc. This paper presents a design of a photovoltaic powered converter to provide regulated AC voltage. The system consists of a buck chopper and an inverter. The chopper acts as a Maximum Power Point Tracker to optimize the battery charging...
Due to the rapid increase of nonlinear and unbalanced reactive loads in 4-wire distribution systems, various power quality issues such as harmonics current, unbalanced load currents, neutral current and low power factor occur. The need for green and renewable energy sources increases daily due to increase in demand for electrical power. Photovoltaic (PV) energy is an important renewable technology...
Usage of renewable energy is rapidly growing in last times. Photovoltaic energy has a big potential to supply the households in the near future. Small photovoltaic power systems are being developed in last years. Many issues are connected with this type power system. New inverter topologies are developed to handle effective photovoltaic power system connected to the grid. In the paper, parameters...
The Current-Source Flyback micro-inverter is widely used in ac-PV module applications, operated either on Discontinuous Conduction Mode (DCM) or Boundary Conduction Mode (BCM). However, each mode has its performance disadvantages (either low power density for DCM or low efficiency due to increased switching losses for BCM). To overcome the above, a hybrid DBCM operation is proposed hereafter, taking...
A battery energy storage system (BESS) for a utility scale photovoltaic (PV) power plant is proposed. PV systems suffer from intermittency and partial shading problems, which could lead to power fluctuations and reduce grid stability. Utilities' inability to service the contracted load might lead to hefty penalties by the regulators. To reduce the effects of intermittency on PV output, a utility scale...
The self-consumption of PV-systems can be increased with a battery. The proposed three-phase inverter provides three independent DC inputs that can each be connected to a battery or a PV-string. The innovative topology allows energy flow in each direction at a very high efficiency (> 98 % in each converter stage). The application of SiC transistors leads to a higher switching frequency (48 kHz)...
The transformerless grid-connected PV system suffers from leakage current and neutral voltage imbalance if three-level inverters are utilized. This paper first investigates the common-mode voltage (CM voltage) reduction/elimination methods in three-phase PV inverters, especially three-level inverters. Several mainstream common-mode voltage reduction/elimination methods, including AZSPWM, 2MV1Z, 3MV,...
Recent studies show that Silicon Carbide and Gallium Nitride based power semiconductors promise better performance over conventional Silicon based devices. In this study, the performance analysis of a three level inverter based on SiC and GaN is discussed for photovoltaic applications. The converter can achieve 99.2% efficiency at 16kHz switching frequency and 1.4kW output power, and operate with...
This paper presents a macroscopic comparison between the global energy efficiency of DC and AC local microgrid in urban areas. Aiming to reduce multiple energy conversions and based on an industrial photovoltaic inverter efficiency obtained experimentally, the technical feasibility results lead to DC network distribution for building-integrated DC microgrid.
In this paper, two control strategies based on space vector modulation (SVM) technique are developed for a five-level current source converter (CSC) based STATCOM. In case of control strategy-1, DC-link currents are kept constant, and the reactive power is varied by changing the modulation index. On the other hand, in case of control strategy-2, DC-link currents are varied in accordance with reactive...
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