scholarly journals Optimal Multiobjective Control of Low-Voltage AC Microgrids: Power Flow Regulation and Compensation of Reactive Power and Unbalance

2020 ◽  
Vol 11 (2) ◽  
pp. 1239-1252 ◽  
Author(s):  
Danilo I. Brandao ◽  
Willian M. Ferreira ◽  
Augusto M. S. Alonso ◽  
Elisabetta Tedeschi ◽  
Fernando P. Marafao
Keyword(s):  
Power Flow ◽  
Reactive Power ◽  
Low Voltage ◽  
Flow Regulation ◽  
Multiobjective Control

scholarly journals Behaviour of Distribution Grids with the Highest PV Share Using the Volt/Var Control Chain Strategy

Energies ◽  
2019 ◽  
Vol 12 (20) ◽  
pp. 3865 ◽  
Author(s):  
Daniel-Leon Schultis ◽  
Albana Ilo
Keyword(s):  
Power Flow ◽  
Large Scale ◽  
Reactive Power ◽  
Low Voltage ◽  
Information And Communications Technology ◽  
Optimal Arrangement ◽  
Reactive Power Flow ◽  
Voltage Limit ◽  
Scale Integration ◽  
Distribution Grids

The large-scale integration of rooftop PVs stalls due to the voltage limit violations they provoke, the uncontrolled reactive power flow in the superordinate grids and the information and communications technology (ICT) related challenges that arise in solving the voltage limit violation problem. This paper attempts to solve these issues using the LINK-based holistic architecture, which takes into account the behaviour of the entire power system, including customer plants. It focuses on the analysis of the behaviour of distribution grids with the highest PV share, leading to the determination of the structure of the Volt/var control chain. The voltage limit violations in low voltage grid and the ICT challenge are solved by using concentrated reactive devices at the end of low voltage feeders. Q-Autarkic customer plants relieve grids from the load-related reactive power. The optimal arrangement of the compensation devices is determined by a series of simulations. They are conducted in a common model of medium and low voltage grids. Results show that the best performance is achieved by placing compensation devices at the secondary side of the supplying transformer. The Volt/var control chain consists of two Volt/var secondary controls; one at medium voltage level (which also controls the TSO-DSO reactive power exchange), the other at the customer plant level.

scholarly journals Photovoltaic Power Converter Management in Unbalanced Low Voltage Networks with Ancillary Services Support

Energies ◽  
2019 ◽  
Vol 12 (6) ◽  
pp. 972 ◽  
Author(s):  
Fermín Barrero-González ◽  
Victor Pires ◽  
José Sousa ◽  
João Martins ◽  
María Milanés-Montero ◽  
...  
Keyword(s):  
Power Flow ◽  
Reactive Power ◽  
Low Voltage ◽  
Renewable Energy Sources ◽  
Distribution Network ◽  
Power Converter ◽  
Maximum Energy ◽  
Practical Implementation ◽  
Network Operation ◽  
The Impact

The proliferation of residential photovoltaic (PV) prosumers leads to detrimental impacts on the low-voltage (LV) distribution network operation such as reverse power flow, voltage fluctuations and voltage imbalances. This is due to the fact that the strategies for the PV inverters are usually designed to obtain the maximum energy from the panels. The most recent approach to these issues involves new inverter-based solutions. This paper proposes a novel comprehensive control strategy for the power electronic converters associated with PV installations to improve the operational performance of a four-wire LV distribution network. The objectives are to try to balance the currents demanded by consumers and to compensate the reactive power demanded by them at the expense of the remaining converters’ capacity. The strategy is implemented in each consumer installation, constituting a decentralized or distributed control and allowing its practical implementation based on local measurements. The algorithms were tested, in a yearly simulation horizon, on a typical Portuguese LV network to verify the impact of the high integration of the renewable energy sources in the network and the effectiveness and applicability of the proposed approach.

Optimal Placement of Reactive Power Compensation Banks for the Maximization of New Generation Capacity

2005 ◽  
Vol 4 (1) ◽  
Author(s):  
Panagis N. Vovos ◽  
Janusz W Bialek
Keyword(s):  
Power Flow ◽  
Optimal Power Flow ◽  
Reactive Power ◽  
Low Voltage ◽  
Network Capacity ◽  
Optimal Placement ◽  
Test Case ◽  
Investment Cost ◽  
Generation Capacity ◽  
New Generation

The aim of this paper is to present a novel method for the optimal placement of capacitor and reactor banks, with the objective of maximizing network capacity to absorb new generation. The method is an extension of the Optimal Power Flow used as a tool for network capacity analysis. It can be used to a) plot graphs of the bank investment cost with respect to the increase in network capacity and b) find the optimum investment for the network operator in order to maximize his revenue. A 12-bus low voltage network was used as a test case. The results demonstrate the efficiency of the method to allocate new banks. At a small investment cost, network capacity could nearly double.

scholarly journals Smart Integration of a DC Microgrid: Enhancing the Power Quality Management of the Neighborhood Low-Voltage Distribution Network

Inventions ◽  
2019 ◽  
Vol 4 (2) ◽  
pp. 25
Author(s):  
Ahmed F. Ebrahim ◽  
Ahmed A. Saad ◽  
Osama Mohammed
Keyword(s):  
Power Quality ◽  
Power Flow ◽  
Reactive Power ◽  
Low Voltage ◽  
Distribution Network ◽  
Nonlinear Behavior ◽  
Electrical Equipment ◽  
Voltage Source ◽  
Voltage Distribution ◽  
Dc Microgrid

The fast development of the residential sector regarding the additional integration of renewable distributed energy sources and the modern expansion usage of essential DC electrical equipment may cause severe power quality problems. For example, the integration of rooftop photovoltaic (PV) may cause unbalance, and voltage fluctuation, which can add constraints for further PV integrations to the network, and the deployment of DC native loads with their nonlinear behavior adds harmonics to the network. This paper demonstrates the smart integration of a DC microgrid to the neighborhood low-voltage distribution network (NLVDN). The DC microgrid is connected to the NLVDN through a three-phase voltage source inverter (VSI), in which the VSI works as a distribution static compensator (DSTATCOM). Unlike previous STATCOM work in the literature, the proposed controller of the VSI of the DC smart building allows for many functions: (a) it enables bidirectional active/reactive power flow between the DC building and the AC grid at point of common coupling (PCC); (b) it compensates for the legacy unbalance in the distribution network, providing harmonics elimination and power factor correction capability at PCC; and (c) it provides voltage support at PCC. The proposed controller was validated by Matlab/Simulink and by experimental implementation at the lab.

scholarly journals Low Voltage Ride Through Controller for a Multi-Machine Power System Using a Unified Interphase Power Controller

Electronics ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 585
Author(s):  
Atoosa Majlesi ◽  
Mohammad Reza Miveh ◽  
Ali Asghar Ghadimi ◽  
Akhtar Kalam
Keyword(s):  
Power System ◽  
Power Flow ◽  
Transient Stability ◽  
Reactive Power ◽  
Low Voltage ◽  
Voltage Drop ◽  
Energy Resource ◽  
Unified Power Flow Controller ◽  
Power Controller ◽  
Low Voltage Ride Through

In recent years, grid-connected photovoltaic (PV) power generations have become the most extensively used energy resource among other types of renewable energies. Increasing integration of PV sources into the power network and their dynamic performances under fault conditions is an important issue for grid code requirements. In this paper, a PV source as a unified interphase power controller (UIPC) is used to enhance the low voltage ride through (LVRT) and transient stability of a multi-machine power system. The suggested PV-based UIPC consists of two series voltage inverters and a parallel inverter. The UIPC injects the required active and reactive power to prevent voltage drop under grid fault conditions. Accordingly, a dynamic control system is designed based on proportional-integral (PI) controllers for the PV-based UIPC to operate in both normal and fault conditions. Simulations are done using Matlab/Simulink software, and the performance of the PV-based UIPC is compared with the conventional unified power flow controller (UPFC). The results of this study indicate the more favorable impact of the PV-based UIPC on the system compared to UPFC in improving LVRT capabilities and transient stability.

scholarly journals Impact of Changes in a Distribution Network Nature on the Capacitive Reactive Power Flow into the Transmission Network in Slovakia

Energies ◽  
2021 ◽  
Vol 14 (17) ◽  
pp. 5321
Author(s):  
Matej Tazky ◽  
Michal Regula ◽  
Alena Otcenasova
Keyword(s):  
Power Flow ◽  
Reactive Power ◽  
Power Transmission ◽  
Low Voltage ◽  
Point Of View ◽  
Electricity System ◽  
Reactive Power Flow ◽  
Main Emphasis ◽  
The Impact ◽  
Lower Voltage

The main emphasis in the operation of an electricity system is placed on its safe and reliable operation. The flow of reactive power in a network can affect voltage conditions in individual nodes of the transmission system. In recent years, there have been changes in the network that have resulted in increased capacitive reactive power flows from lower voltage levels to higher ones. These flows can cause the voltage to rise above the limit. This paper examines recent changes in the reactive power transmission in the network, especially at lower voltage levels. The possible impact of these changes on the flow of capacitive reactive power at higher voltage levels is analyzed. This paper also presents a description and the simulated impact of power lines at different voltage levels on reactive power flows. Real measurements of different types of consumers at the low-voltage (LV) level are analyzed. Finally, a simulation model was created to simulate the impact of a customer’s power contribution to the reactive power flows from the point of view of a 110 kV voltage node. This node is characterized as a supply point.

scholarly journals Comparison of Reactive Power Control Techniques for Solar PV Inverters to Mitigate Voltage Rise in Low-Voltage Grids

Electronics ◽  
2021 ◽  
Vol 10 (13) ◽  
pp. 1569
Author(s):  
Dilini Almeida ◽  
Jagadeesh Pasupuleti ◽  
Janaka Ekanayake
Keyword(s):  
Power Control ◽  
Power Factor ◽  
Power Flow ◽  
Reactive Power ◽  
Low Voltage ◽  
Voltage Regulation ◽  
Solar Pv ◽  
Reactive Power Control ◽  
Control Techniques ◽  
Power Factor Control

The greater integration of solar photovoltaic (PV) systems into low-voltage (LV) distribution networks has posed new challenges for the operation of power systems. The violation of voltage limits attributed to reverse power flow has been recognized as one of the significant consequences of high PV penetration. Thus, the reactive power control of PV inverters has emerged as a viable solution for localized voltage regulation. This paper presents a detailed study on a typical Malaysian LV distribution network to demonstrate the effectiveness of different reactive power control techniques in mitigating overvoltage issues due to high PV integration. The performance of four reactive power control techniques namely, fixed power factor control, scheduled power factor control, power factor control as a function of injected active power, and voltage-dependent reactive power control were analyzed and compared in terms of the number of customers with voltage violations, reactive power compensation, and network losses. Three-phase, time-series, high-resolution power-flow simulations were performed to investigate the potential overvoltage issues and to assess the performance of the adoption of reactive power controls in the network. The simulation results revealed that the incorporation of reactive power controls of solar PV inverters aids in successfully mitigating the overvoltage issues of typical Malaysian networks. In particular, the Volt-Var control outperformed the other control techniques by providing effective voltage regulation while requiring less reactive power compensation. Furthermore, the comparative analysis highlighted the significance of employing the most appropriate control technique for improved network performance.

scholarly journals On the Correction of the Power Factor in Modern Low-Voltage Power Electrical Installations

2017 ◽  
Vol 17 (2) ◽  
pp. 10-15 ◽  
Author(s):  
Emil Cazacu ◽  
Marilena Stănculescu ◽  
Horia Andrei
Keyword(s):  
Power Quality ◽  
Power Factor ◽  
Power Flow ◽  
Reactive Power ◽  
Low Voltage ◽  
Harmonic Distortion ◽  
Quality Parameters ◽  
Specific Power ◽  
Industrial Installation ◽  
Reactive Power Flow

AbstractThe paper presents the main electrical loads that require reactive power, evaluating also its value in different operating states of the industrial installation (permanent sinusoidal or distorted). Also, the effects of reactive power flow in the networks are quantitatively estimated and accordingly, a series of specific power quality indicators (e.g. power factor, crest factor, total harmonic distortion) are highlighted. Different types of solutions dedicated to reduce the level of reactive power are also suggested. The proper design of the power factor correction systems is directly correlated with the consumer power quality parameters. A case-study will round up the work, underling the major importance of the reactive power flow in modern electric installations.

Flexible Genetic Algorithm Based Optimal Power Flow of Power Systems

2018 ◽  
Vol 24 (3) ◽  
pp. 84
Author(s):  
Hassan Abdullah Kubba ◽  
Mounir Thamer Esmieel
Keyword(s):  
Genetic Algorithm ◽  
Objective Function ◽  
Power Flow ◽  
Optimal Power Flow ◽  
Reactive Power ◽  
Test System ◽  
Multi Objective ◽  
Optimal Power ◽  
Blending Method ◽  
Real Coded Genetic Algorithm

Nowadays, the power plant is changing the power industry from a centralized and vertically integrated form into regional, competitive and functionally separate units. This is done with the future aims of increasing efficiency by better management and better employment of existing equipment and lower price of electricity to all types of customers while retaining a reliable system. This research is aimed to solve the optimal power flow (OPF) problem. The OPF is used to minimize the total generations fuel cost function. Optimal power flow may be single objective or multi objective function. In this thesis, an attempt is made to minimize the objective function with keeping the voltages magnitudes of all load buses, real output power of each generator bus and reactive power of each generator bus within their limits. The proposed method in this thesis is the Flexible Continuous Genetic Algorithm or in other words the Flexible Real-Coded Genetic Algorithm (RCGA) using the efficient GA's operators such as Rank Assignment (Weighted) Roulette Wheel Selection, Blending Method Recombination operator and Mutation Operator as well as Multi-Objective Minimization technique (MOM). This method has been tested and checked on the IEEE 30 buses test system and implemented on the 35-bus Super Iraqi National Grid (SING) system (400 KV). The results of OPF problem using IEEE 30 buses typical system has been compared with other researches.     

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