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Islanding detection has been the focus of significant research efforts during the last years. Islanding detection methods can be remote or local, the last being further divided into active and passive methods. Active methods have a reduced non-detection zone (NDZ) and ease of implementation. However they require the injection of some disturbing signal into the grid to measure its response, therefore...
This paper proposes a control architecture of distributed generators (DGs) inverters and shunt active power filters (APFs) in microgrids to compensate voltage harmonics in a coordinated way. For this, a hierarchical control structure is proposed that includes two control levels. The primary (local) control consists of power controllers, selective virtual impedance loops and proportional-resonant (PR)...
One of the major issues in a single phase inverter topology is the 120Hz ripple which needs large decoupling capacitors. Big bulky electrolytic capacitors can be an issue in applications where compact size and high power density are requirements such as solar converter chargers. In z source inverter systems, the design of the impedance network is critical. In single phase z source inverter systems,...
The main goal of this paper is to underline the limitations of LCL interface filter used in three-phase shunt active power filter for active traction substations. Starting from the two main functions that should be fulfilled by the interface filter, i.e. let them unchanged the current harmonics that must be compensated and stop harmonics due to inverter switching, it is shown that they can not be...
In order to improve the power quality of renewable energy-based microgrids when unbalanced non-linear loads and generations occur, the integration of active filter functions into energy storage systems has been investigated. A four-leg voltage-source inverter supplied by a lithium iron phosphate battery has been considered. A control system, aimed to integrate the battery energy management with the...
This paper is focused on a single phase shunt active filter based on detection of harmonic voltages at the point of installation; the mission of the active filter is to eliminate these harmonic voltages implementing a repetitive-based control. The active filter is a single-phase voltage-controlled voltage source inverter controlled so to generate a harmonic voltage in phase with the one detected at...
Researches related to non-conventional energy sources have grown significantly in the present scenario. The electrical energy from the PV panel is considered as one of the most useful natural resources. This paper deals with the operation and control of a grid connected PV system with a nonlinear load. A utility grid connection is provided in order to replenish energy levels in case of power shortage...
This paper presents a novel control scheme for seven levels diode clamped multilevel inverter (DCMLI) topology based shunt hybrid active power filter which can compensate both dynamic reactive power and current harmonics in three phase three wire medium voltage distribution power systems as against many literatures that compensate fixed reactive power. It is on account of this novel control method,...
The use of renewable energy sources for the generation of electricity is been extensively used these days due to many aspects like to reduce pollution, to meet load demands, extinction of conventional fuels and many more. This paper gives a detailed analysis of grid connected renewable source in a three phase four wire distribution system with power quality improvement feature. Power quality is necessary...
Protection of Distributed Generation (DG) injected Distribution network (DN) is a challenging task in entire electrical ancestors. The connection of DG to the distribution network alters the nature of the network. Expose of DG can alter the fault current during the grid disturbance or external fault and perturb the existing distribution protection system, one of them in the event of a fault where...
In the present scenario energy resources are being used at an alarmingly high rate. In order to ensure that younger generations are not deprived of their energy usage, India now considers wind and solar as an alternative for future energy demands. In India incidence of solar energy in land area alone is 5000 trillion kilowatt hours which exceeds the energy outcome of all possible non renewable energy...
This paper presents harmonic performance analysis of autonomous minigrid integrated distributed power system, seen from a power-quality viewpoint using FFT analysis; describes the main relations between minigrid and harmonics, and goes into some detail for some of the aspects. The main aim of this paper is to explain the effects of harmonics in the minigrid side and steps to reduce harmonics. This...
Repetitive control strategies have been commonly applied in pulse-width modulated (PWM) inverters for many industrial applications. The phase delay in the overall control system, e.g. the delay caused by the digital duty cycle calculation, PWM generation and the repetitive controller, has to be compensated by elaborately designed phase lead filters in order to prevent control performance deterioration...
There has been a growing demand of using multi-function inverters for grid-connected systems applied to nonconventional energy sources, such as solar, wind and so on. In addition to power quality conditioning, the inverter can also be used for bidirectional active power exchange with a three-phase four-wire grid. Therefore, the inverter acts as a multi-function compensator. The functions of the proposed...
In this paper, control of a grid-tied converter as a voltage controlled converter is investigated for distribution level grids. Small signal model of the converter is presented and a control structure is designed to deliver desired active and reactive power. This controller is using power flow equations to control the converter as a synchronous machine and without the need for a dedicated synchronization...
In this paper, the power quality of microgrids is addressed. To achieve the desired level of power quality, a strategy based on the coordinated control between DGs and APFs is proposed. In this regard, hierarchical control is applied where primary control consists of power droop controller of DGs, selective virtual impedance and voltage/current regulators. Based on the secondary control, at first...
Nowadays with respect to growth of sensitive loads in power grid, power quality improvement is undeniable. One of power quality improvement techniques is using distribution generation interfaces as an active filter (DG-active filter). Because of some benefits of DG-active filters, such as active and reactive power injection, harmonic current injection and power factor improvement, they are attracting...
Present work aims to remove the source current harmonics of order 6n±1 where, n is an integer present in power utility system under realistic scenario. This realistic scenario represents a harmonically unbalanced condition which is caused by multiple non-linear loads attached to different phases of 3-phase power supply. It creates different amplitude spectrum of individual source current harmonic...
The present work aims to remove dominant current harmonics (5th,7th,11th and 13th) of a 240V(rms) utility at the point of common coupling for the harmonically unbalanced condition of source current, using parallel combination of two shunt hybrid active filters. The harmonically unbalanced condition of source current has been created by connecting different types of non-linear loads in different phases...
Integration of Photovoltaic system to grid through voltage source inverter is presented in this paper. The PV-grid system is connected to nonlinear load. To reduce the harmonics due to nonlinear load, a filtering technique is employed. This is nothing but one voltage source inverter which act as active power filter. Incremental Conductance based MPPT is employed which gives the reference value of...
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