Reactive power and voltage regulation in micro grids environment

2013 ◽  
Vol 4 (1) ◽  
pp. 49-56
Author(s):  
I. Vokony
Keyword(s):  
Energy Distribution ◽  
Reactive Power ◽  
Distribution Networks ◽  
Voltage Regulation ◽  
Electricity Supply ◽  
Voltage Quality ◽  
Micro Grid ◽  
Grid Operation ◽  
Micro Grids

Abstract This paper is a continuation of the paper “Examination of Micro Grid Operation in Island Condition, Focusing on Voltage Control” [10]. It has presented the assessment of micro grids’ voltage and reactive power control. The increasing integration of intelligent energy distribution networks has to serve the interest of the consumers. Therefore, it is necessary to examine the quality of the electricity supply with regard to the voltage quality as well. How is it possible to ensure the regulation in those cases, e.g. in case of island operation? In the paper the model developed and used for simulating the micro grids are introduced and it is also shown how to apply them for island operation assessment. With the help of a model network the results of the simulations are presented and the conclusions are evaluated.

scholarly journals Using Energy Storage Inverters of Prosumer Installations for Voltage Control in Low-Voltage Distribution Networks

Energies ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 1121
Author(s):  
Rozmysław Mieński ◽  
Przemysław Urbanek ◽  
Irena Wasiak
Keyword(s):  
Energy Storage ◽  
Control Strategy ◽  
Reactive Power ◽  
Low Voltage ◽  
Storage System ◽  
Distribution Networks ◽  
Energy Storage System ◽  
Voltage Regulation ◽  
Active Power ◽  
Total Power

The paper includes the analysis of the operation of low-voltage prosumer installation consisting of receivers and electricity sources and equipped with a 3-phase energy storage system. The aim of the storage application is the management of active power within the installation to decrease the total power exchanged with the supplying network and thus reduce energy costs borne by the prosumer. A solution for the effective implementation of the storage system is presented. Apart from the active power management performed according to the prosumer’s needs, the storage inverter provides the ancillary service of voltage regulation in the network according to the requirements of the network operator. A control strategy involving algorithms for voltage regulation without prejudice to the prosumer’s interest is described in the paper. Reactive power is used first as a control signal and if the required voltage effect cannot be reached, then the active power in the controlled phase is additionally changed and the Energy Storage System (ESS) loading is redistributed in phases in such a way that the total active power set by the prosumer program remains unchanged. The efficiency of the control strategy was tested by means of a simulation model in the PSCAD/EMTDC program. The results of the simulations are presented.

Uticaj solarne elektrane na kvalitet električne energije u niskonaponskoj distributivnoj mreži

2020 ◽  
Vol 22 (1-2) ◽  
pp. 137-144
Author(s):  
Hidajet Salkić ◽  
Amir Softić ◽  
Amer Salkić
Keyword(s):  
Power Quality ◽  
Negative Feedback ◽  
Electricity Market ◽  
Reactive Power ◽  
Electric Power System ◽  
Integrated System ◽  
Distributed Source ◽  
Voltage Quality ◽  
Number Of Customers

The electric power system, as an integrated system for transmission, distribution and consumption of electricity, is one of the most complex technical and economic systems today. Customers affect on the voltage quality of power network, but the network also has an impact on customers. All disturbances in the network can disrupt operation of the network and affect on operation of the customers, as well as reduce the level of efficiency and operation life or even seriously damage network. Number of customers is increasing every day, as well as proportion of customers who generate disturbances in the network and, at the same time, are sensitive to them. These circumstances impose the need for frequent monitoring of the network, so the analysis of power quality is not unjustified cost but extremely important and profitable investment. The quality of electricity, as part of the overall quality supply of electricity customers in deregulated conditions of liberal electricity market becomes significant regulatory parameter for network operators and a significant contracting parameter on the electricity market. Network operators are obliged to establish a system of individual measurements and a system of permanent monitoring of power quality parameters to determine the state and improve the parameters to the standardized level. Technical parameters are determined by the recommendations made at the international level and may, but do not need, be legally binding. Maintaining a certain level of voltage quality at some point of the network is the responsibility of electricity distributor. This task distributor executes by limiting of negative effects of producer/customer to the network. Therefore, each electricity producer/customer is obliged to reduce own negative feedback effects (injection of higher harmonics, taking of reactive power, emissions of flickers and loads unbalances) to a prescribed, prearranged, limited values. There are many norms that describe the quality of electricity, but in Europe the best known is EN50160 (issued by CENLEC). This paper presents the approach to measuring the voltage quality at the point of electricity delivery from distributed source into distribution network from the aspect of limiting the negative feedback of distributed source on the voltage quality.

scholarly journals Induction Motor Drives Fed by an NPC Inverter with Unbalanced DC-Link

Electronics ◽  
2019 ◽  
Vol 8 (12) ◽  
pp. 1379 ◽  
Author(s):  
Umberto Abronzini ◽  
Ciro Attaianese ◽  
Matilde D’Arpino ◽  
Mauro Di Monaco ◽  
Giuseppe Tomasso
Keyword(s):  
Output Voltage ◽  
Harmonic Distortion ◽  
Voltage Regulation ◽  
Motor Drives ◽  
Operating Conditions ◽  
Switching Frequency ◽  
Voltage Level ◽  
Voltage Quality ◽  
Vector Modulation

Neutral Point Clamped (NPC) converters with n levels are traditionally controlled in such a way that the DC-link capacitors operate at 1/( n - 1) of the total DC-link voltage level. The voltage level across the DC-link capacitors has to be properly regulated by the capacitor unbalance control to contain the harmonic distortion of the converter output voltages. State-of-the-art modulation techniques address the problem of the DC-link voltage regulation for NPC inverters. However, they highly show reduced performance when unbalanced DC-link voltages are considered. In this paper, a novel Space Vector Modulation (SVM) is proposed for NPC converters with an unbalanced DC-link. At every modulation interval, the technique defines the optimal switching pattern by considering the actual unbalanced DC-link conditions. The proposed modulation allows improving the harmonic content of the NPC converter output voltage with respect to a traditional ML-SVM, when the same operating conditions are considered. As an extension, the proposed modulation technique will guarantee the same output voltage quality of a traditional ML-SVM with unbalanced DC-link, while improving the conversion efficiency thanks to a reduction of switching frequency.

scholarly journals Power factor control of PV generators in local distribution networks using fuzzy logic concept

2018 ◽  
Vol 7 (2.28) ◽  
pp. 362
Author(s):  
Raed A. Shalwala
Keyword(s):  
Fuzzy Logic ◽  
Control System ◽  
Power Factor ◽  
Fuzzy Logic Control ◽  
Reactive Power ◽  
Distribution Network ◽  
Voltage Control ◽  
Distribution Networks ◽  
Voltage Regulation ◽  
Logic Control

One of the most important operational requirements for any electrical power network for both distribution and transmission level is voltage control. Many studies have been carried out to improve or develop new voltage control techniques to facilitate safe connection of distributed generation. In Saudi Arabia, due to environmental, economic and development perspectives, a wide integration of photovoltaic (PV) genera-tion in distribution network is expected in the near future. This development in the network may cause voltage regulation problems due to the interaction with the existing conventional control system. In a previous paper, a control system has been described using a fuzzy logic control to set the on-line tap changer for the primary substation. In this paper a new control system is proposed for controlling the power factor of individual PV invertors based on observed correlation between net active and reactive power at each connection. A fuzzy logic control has been designed to alter the power factor for the remote invertors from the secondary substation to keep the feeder voltage within the permissible limits. In order to confirm the validity of the proposed method, simulations are carried out for a realistic distribution network with real data for load and solar radiation. Results showing the performance of the new control method are presented and discussed.  

Analysis of Thyristor Switched Three-Phase Capacitor

2013 ◽  
Vol 722 ◽  
pp. 311-316 ◽  
Author(s):  
Tian Xiang Yan ◽  
Xiao Lan Xie ◽  
Xin Yu Chen ◽  
Peng Niu
Keyword(s):  
Reactive Power ◽  
Power Transmission ◽  
Switching Time ◽  
Transition Process ◽  
Fundamental Principle ◽  
Safe Operation ◽  
Voltage Quality ◽  
Three Phase ◽  
Selection Of

it can limit the reactive power transmission to improve the voltage quality of power grid by installing parallel capacitors for reactive power compensation. But due to presence of transient transition process during power capacitors switching, it will seriously affect the service life of power capacitors and the safe operation of power system if the switching process of capacitors is not properly controlled. Firstly, this article described the fundamental principle and switching conditions of Thyristor Switched Capacitor (TSC). Secondly, the selection of switching time was analyzed for Thyristor Switched Three-phase Capacitor (TSTC). Finally, the simulation for TSTC was carried out by using MATLAB to verify the feasibility of analysis.

scholarly journals Generation of Optimal Switching Angle for Nine Level Cascaded H Bridge MLI Using Most Valuable Player Algorithm

2021 ◽  
Vol 12 (6) ◽  
pp. 1919-1927
Author(s):  
Vijaya Anand N, Hema Latha J, G Devadasu, Kumar C
Keyword(s):  
Reactive Power ◽  
Harmonic Distortion ◽  
Voltage Level ◽  
Computing Technique ◽  
Power Exchange ◽  
Point Of Common Coupling ◽  
Terminal Voltage ◽  
Common Coupling ◽  
Micro Grids

Distributed generation (DG) sources often interfaced with grid by a Cascaded H-bridge multilevel inverter with a remote D.C source. The interface inverter has to adapt voltage on the either side of the grid and DG source while it has a control of active and reactive power exchange. The inverter terminal voltage is maintained based on frequency switching technique. However, in applications like micro grids are based on quality of output voltage at the point of common coupling. The present paper discusses an optimal frequency switching methodology that generates optimal fringing angle based on an evolutionary computing technique while maintaining the voltage level at PCC with a reduced harmonic distortion.  Efficacy of the proposed method is illustrated by simulating a 9-level cascaded H bridge in MATLAB environment.

scholarly journals Improving quality of ac electric power supply of autonomous power sources using in agriculture

2020 ◽  
Vol 193 ◽  
pp. 01024
Author(s):  
Olga Milashkina ◽  
Vadim Zlobin
Keyword(s):  
Power Supply ◽  
Voltage Regulation ◽  
Voltage Regulators ◽  
Electricity Supply ◽  
Control Laws ◽  
Power Sources ◽  
Electric Power Supply ◽  
Use Of Technology ◽  
Supply Systems

Autonomous AC electricity supply systems are now widely introduced in agriculture. As the experience of operation of these electricity supply systems has shown, their various properties, determined largely by the type of voltage regulators and sensors used, do not always fully meet the constantly growing requirements for the quality of electricity. Further improvement of voltage regulation systems, and, consequently, the quality of electricity, is associated with the use of technology in them that can implement optimal control laws.

scholarly journals Capacitor Siting and Sizing using Cost Minimization & Monty Carlo Simulations for RDS

2019 ◽  
Vol 8 (3) ◽  
pp. 2482-2489
Keyword(s):  
Reactive Power ◽  
Cost Minimization ◽  
Minimum Cost ◽  
Distribution Networks ◽  
Voltage Regulation ◽  
System Capacity ◽  
Design Stage ◽  
Loss Reduction ◽  
Minimization Algorithm ◽  
Optimal Value

Capacitors are widely used in distribution networks for energy loss reduction, reactive power compensation, voltage regulation, and for system capacity release. However, it’s important that the system is designed initially, and capacitors are applied in correct magnitude and at right node to achieve best results. The most important task for distribution engineer is to efficiently simulate the system at design stage and later apply optimum capacitance injection. The work presented in this paper proposes a cost minimization algorithm using a unique mathematical model along with Monty carlo simulation to choose optimal value of capacitors, both fixed and switching based on total minimum cost algorithm.

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