1,721,021 research outputs found
Power quality and custom power: Seeking for a common solution in LV distribution network
No full textPower Quality (PQ) and Custom Power (CP) are two different terms in electric power system. PQ is the definition of a unique standard which the distribution system operators (DSO) should respect precisely. The DSO can manage its network to address the PQ issues but the result could satisfy only some end users requirements while others could need to improve their voltage profile. Therefore, the custom needs can be not completely satisfied by this standard and with the term CP we define the end user needs. This paper presents PQ and CP definitions and tries to find a possible common solution for DSO and final users in a contest where power electronics play an important role. Indeed in this new concept of distribution electricity network, as application in smart grid, there is a huge diffusion of renewable energy sources and storage systems. In this contest a solution able to provide economic benefits to DSO and end users needs to be found
Open UPQC series and shunt units cooperation within Smart LV Grid
No full textPower Quality within LV distribution and Smart Grid systems is an important issue. Open Unified Power Quality Conditioner (Open UPQC) is a possible solution to improve power quality level within distribution smart grid networks. This paper presents the ICT-based power control in order to manage cooperation between series and shunt units of Open UPQC. The cooperation is meant to improve system functionality and performance. Considering that the device is installed in a real network, under test network is simulated by MATLAB SimPower system in order to illustrate effectiveness of the control strategy
Cascade PI controller for single-phase STATCOM
No full textThis paper presents state space model of singlephase STATCOM based on continues switching function. Continues switching functions for bipolar voltage source inverter (VSI) have been used to derive the transfer function for complete controller. Two proportional integral (PI) controllers which are a DC PI for DC link voltage control and an AC PI for alternating current control are implemented in cascade topology in reactive power compensation. Proposed control method has been analyzed in simulation by using MATLAB. Root locus technique is used to design AC PI controller parameters
DC or AC distribution? An economic evaluation
No full textElectric energy is the cleanest and more efficient energy type that is being transmitting and distributing among end users. From early evolution, ac distribution was selected as better, from economic point of view, solution for transmission and distribution purpose. However last technological development in electronic device is changing many things. This paper reconsiders DC and ac distribution systems. In particular the paper describes the fundamental aspects in order to compare these solutions from economic point of view and to find better proposal in order to realize new grid or add new loads to an existing grid or even change current ac infrastructure to the DC one. To reach this goal, the paper introduces a cost analysis about the electronic device installed in a LV network. Theoretical evaluation has been conducted and a three line DC distribution is selected as possible economic solution for DC LV grid. A case study is performed to evaluate if it is beneficial to change/build a DC distribution system instead of an ac one
Assessment of two different reactive power estimation methods on single phase loads
No full textIn this paper single-phase instantaneous reactive power (p-q) method and non-active current method have been compared. Reactive power and reactive current calculation using these methods have been considered here under distorted voltage and current waveforms. It has been shown that these two methods have some limitations for reactive power compensation. The p-q method with hysteresis current controller and non-active current theory with sinusoidal pulse width modulation (SPWM) controller have been analyzed in Matlab/Simulink. A prototype system has been designed using TMS320F2812 EzDSP in the laboratory and assessment based on simulation and experimental results is given for these methods in this paper
Reference Voltage Adjustment Strategies for Dynamic Voltage Compensator
No full textModern electrical distribution networks are prone to more severe voltage fluctuations due to the presence of variable loads such as electrical vehicles and renewable energy generation units. These fluctuations decrease both the quality of power and hosting capability of the grid. In such a condition, a Dynamic Voltage Compensator (DVC) can be used to stabilize the voltage of the LV networks. DVC is generally designed to resolve voltage fluctuations reflected from MV systems maintaining the voltage on a constant value. However, it will more effectively improve the voltage quality in the grid if the reference voltage is dynamically adjusted based on measurements inside the LV system. On the other hand, the more complex measurement and coordination strategy may lead to the inapplicability of the methods. Hence, voltage reference adjustment strategies should be developed to conform to the availability of data and measurements inside the grid. Accordingly, in this paper, novel voltage reference adjustment strategies have been developed for DVC based on the measurements in the installation point of the device. In order to examine the proposed methods, they are applied to a LV grid with real measured data and the results are discussed. Based on the provided simulation results, the developed dynamic reference voltage adjustment strategies can successfully improve the quality of voltage and improve the hosting capacity of the LV network
Experiment on Bidirectional Single Phase Converter Applying Model Predictive Current Controller
Full text linkA bidirectional converter able to manage storage is a basic power electronics device, and it is a major component of renewable energy sources, micro grid and also the smart grid concept. In this paper, single-phase bidirectional converter topology is discussed. The state space model has been derived, and a simple model based predictive current controller has been utilized to control the inverter. Control block diagrams have been designed with MATLAB and simulation results are presented and compared with experimental ones, giving credibility to the derived model and the designed control method
Thermal load management: Experimental investigation of voltage variation effect on loads behavior
No full textLoad power and energy demand management is interesting for both end users and Distributed System Operators (DSOs). The electric power principle for linear loads gives less power consumption with lower supply voltage. Active power behavior has been analyzed in literature but often the load reactive power and energy absorption are not analyzed. Moreover, nowadays the development in power electronics is changing the load behavior significantly. This article provides experimental investigation and analysis on technologic electrical thermal loads with the purpose of understanding the electrical behavior of these loads from power and energy point of view by voltage variation. Dynamic Voltage Conditioner (DVC) has been used in order to provide different voltage levels at load terminals. The study will analyze the voltage variation effects on load active power, reactive power and energy consumption behavior
Open UPQC power quality manager within distributed generation systems
No full textPower quality in distribution networks is already a concern in many European Countries where there is a strong presence of renewable energy generation. There is therefore a growing interest in new technologies able to improve the power quality level. Among them, the Open Uninterruptible Power Quality Conditioner (Open UPQC) is a possible solution. The system consists of a main three-phase AC/DC power converter in the MV/LV substation, and some single-phase or three-phase AC/DC power converter installed at customer's premises. The paper discusses design, simulation, implementation of an Open UPQC installed in real distribution grid in the city of Brescia (north of Italy) within Smart Domo Grid, a project co-funded by the Italian Ministry of Economic Development. Some experimental results are also reported
Load management by voltage optimization: Experimental investigation of voltage variation effect on lighting loads
No full textLoad power demand management is important both for final users and for Distributed System Operators (DSOs) in order to manage their network load profile. So several strategies were adopted to get this result, but nowadays the new technologies in electrical loads as lighting systems are changing the electrical loads behaviour. Therefore, it is necessary to reconsider techniques of voltage optimization and their validation. The paper investigates voltage variation effects on several lighting loads. Effect of voltage variation on both Active and Reactive power consumption are taken into account and results are reported in the work
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