scholarly journals Unbalanced and Reactive Currents Compensation in Three-Phase Four-Wire Sinusoidal Power Systems

2020 ◽  
Vol 10 (5) ◽  
pp. 1764 ◽  
Author(s):  
Rafael Montoya-Mira ◽  
Pedro A. Blasco ◽  
José M. Diez ◽  
Rafael Montoya ◽  
Miguel J. Reig
Keyword(s):  
Power Systems ◽  
Positive Sequence ◽  
Electrical System ◽  
System A ◽  
Compensation Methods ◽  
Three Phase ◽  
Zero Sequence ◽  
Unbalanced Loads ◽  
Wire System

In an unbalanced linear three-phase electrical system, there are inefficient powers that increase the apparent power supplied by the network, line losses, machine malfunctions, etc. These inefficiencies are mainly due to the use of unbalanced loads. Unlike a three-wire unbalanced system, a four-wire system has zero sequence currents that circulate through the neutral wire and can be compensated by means of compensation equipment, which prevents it from being delivered by the network. To design a compensator that works with unbalanced voltages, it is necessary to consider the interactions between it and the other compensators used to compensate for negative-sequence currents and positive-sequence reactive currents. In this paper, through passive compensation, a new method is proposed to develop the zero sequence current compensation equipment. The method does not require iteration algorithms and is valid for unbalanced voltages. In addition, the interactions between all compensators are analyzed, and the necessary modifications in the calculations are proposed to obtain a total compensation. To facilitate the application of the method and demonstrate its validity, a case study is developed from a three-phase linear four-wire system with unbalanced voltages and loads. The results obtained are compared with other compensation methods that also use passive elements.

scholarly journals Hybrid power quality conditioner for three-phase four-wire power systems

2020 ◽  
Vol 178 ◽  
pp. 01009
Author(s):  
Maxim Chernyshov ◽  
Valery Dovgun ◽  
Sergei Temerbaev ◽  
Zumeyra Shakurova
Keyword(s):  
Power Systems ◽  
Power Quality ◽  
Single Phase ◽  
Hybrid Power ◽  
Three Phase ◽  
Zero Sequence ◽  
Network Operation ◽  
Power Quality Conditioner ◽  
Wire System ◽  
Nonlinear Nature

The article considers a hybrid power quality conditioner (HQPC) for 3-phase 4-wire systems with a distributed modular structure. Some conditioner modules provide compensation for the component currents and voltages that form the negative and zero sequence systems. The open structure of the HQPC, consisting of independent modules, allows compensating for distortions of currents and voltages of the 3-phase network caused by the nonlinear nature and asymmetry of single-phase loads. The compensation characteristics of the proposed conditioner were researched using a model developed in the MatLab environment. The simulation showed that the proposed conditioner can ensure normalization of power quality in 3-phase 4-wire system at various modes of network operation.

A Three-Phase Model Predictive Approach for Smooth Line-Switching in Islanded Microgrids

2021 ◽  
Author(s):  
Evangelos Pompodakis ◽  
Georgios C. Kryonidis ◽  
Minas Alexiadis
Keyword(s):  
Phase Model ◽  
Positive Sequence ◽  
Distributed Generators ◽  
Three Phase ◽  
Zero Sequence ◽  
Node Network ◽  
Switching Action ◽  
Switching Method ◽  
Line Switching ◽  
Distinct Features

This paper deals with a new line-switching method that facilitates the network reconfiguration of islanded microgrids. Its distinct features include the ability to handle network asymmetries and the minimization of the line current during the switching action. This is attained by developing a sensitive-based three-phase model predictive method to determine the operating set-points of the distributed generators (DGs) that minimize the current of the candidate line participating in the switching action. These set-points correspond to the positive-sequence powers as well as the negative- and zero-sequence currents of all DGs. Furthermore, the network constraints such as voltage limits and power limits of DGs are always satisfied. Simulations are performed in a balanced 33-bus islanded network as well as in the unbalanced IEEE 8500-node network to evaluate the performance of the proposed method.

Power Invariance Transformation in Power Systems

2000 ◽  
Vol 37 (2) ◽  
pp. 180-189
Author(s):  
J. Heydeman ◽  
W. W. Schongs
Keyword(s):  
Power Systems ◽  
Single Phase ◽  
Positive Sequence ◽  
Equivalent Representation ◽  
Symmetrical Components ◽  
Three Phase ◽  
Sequence Components ◽  
Invariance Transformation

Many textbooks describe a balanced three-phase circuit by a single-phase equivalent representation. Confusion may arise amongst students regarding per-unit values of line-to-line voltages and phase voltages and, therefore, about the magnitudes of currents and powers. This paper proposes that students must first be taught symmetrical components based on power invariance transformation. A balanced three-phase circuit is to be described only in terms of positive sequence components. In the authors' experience, students understand this approach better and make fewer errors in per-unit calculation than when they use the single-phase equivalent representation.

A Novel Load Compensation Algorithm under Unbalanced and Distorted Supply Voltages

2007 ◽  
Vol 8 (5) ◽  
Author(s):  
K. Karthikeyan ◽  
Mahesh Kumar Mishra
Keyword(s):  
Supply Voltage ◽  
Positive Sequence ◽  
Active Power Filters ◽  
Power Filters ◽  
Three Phase ◽  
Non Linear ◽  
Detailed Simulation ◽  
Supply Voltages ◽  
Non Linear Load ◽  
Wire System

In this paper, a novel control algorithm is proposed to compensate the unbalanced and non-linear loads in a three-phase four-wire system using active power filters. The algorithm results in balanced and sinusoidal source currents under unbalanced and distorted three-phase supply voltages. The algorithm makes use of the positive sequence extraction of the supply voltage and the theory of instantaneous symmetrical components. To illustrate the concept, a three-phase four-wire system with unbalanced and non-linear load is considered for compensation. The detailed simulation and experimental results are presented to validate the proposed method.

A Three-Phase Model Predictive Approach for Smooth Line-Switching in Islanded Microgrids

2021 ◽  
Author(s):  
Evangelos Pompodakis ◽  
Georgios C. Kryonidis ◽  
Minas Alexiadis
Keyword(s):  
Phase Model ◽  
Positive Sequence ◽  
Distributed Generators ◽  
Three Phase ◽  
Zero Sequence ◽  
Node Network ◽  
Switching Action ◽  
Switching Method ◽  
Line Switching ◽  
Distinct Features

This paper deals with a new line-switching method that facilitates the network reconfiguration of islanded microgrids. Its distinct features include the ability to handle network asymmetries and the minimization of the line current during the switching action. This is attained by developing a sensitive-based three-phase model predictive method to determine the operating set-points of the distributed generators (DGs) that minimize the current of the candidate line participating in the switching action. These set-points correspond to the positive-sequence powers as well as the negative- and zero-sequence currents of all DGs. Furthermore, the network constraints such as voltage limits and power limits of DGs are always satisfied. Simulations are performed in a balanced 33-bus islanded network as well as in the unbalanced IEEE 8500-node network to evaluate the performance of the proposed method.

scholarly journals Compensation of Reactive Power and Unbalanced Power in Three-Phase Three-Wire Systems Connected to an Infinite Power Network

2019 ◽  
Vol 10 (1) ◽  
pp. 113 ◽  
Author(s):  
Pedro A. Blasco ◽  
Rafael Montoya-Mira ◽  
José M. Diez ◽  
Rafael Montoya ◽  
Miguel J. Reig
Keyword(s):  
Linear Systems ◽  
Reactive Power ◽  
Current System ◽  
Positive Sequence ◽  
Power Network ◽  
Negative Sequence ◽  
Three Phase ◽  
Network Losses ◽  
Infinite Power

The compensation of an electrical system from passive compensators mainly focuses on linear systems where the consumption of charges does not vary significantly over time. In three-phase three-wire systems, when the network voltages are unbalanced, negative-sequence voltages and currents appear, which can significantly increase the total apparent power supplied by the network. This also increases the network losses. This paper presents a method for calculating the compensation of the positive-sequence reactive power and unbalanced powers caused by the negative-sequence line currents using reactive elements (coils and/or capacitors). The compensation is applied to three-phase three-wire linear systems with unbalanced voltages and loads, which are connected to an infinite power network. The method is independent of the load characteristics, where only the line-to-line voltages and line currents, at the point where compensation is desired, need to be known in advance. The solution obtained is optimal, and the system observed from the network behaves as one that only consumes the active power required by a load with a fully balanced current system. To understand the proposed method and demonstrate its validity, a case study of a three-phase three-wire linear system connected to an infinite power network with unbalanced voltages and currents is conducted.

scholarly journals Three-phase Quaternion Power in Three-wire Systems

2021 ◽  
Vol 19 ◽  
pp. 493-498
Author(s):  
André S. F. Komeno ◽  
◽  
Anésio L. F. Filho ◽  
Joao Y. Ishihara ◽  
Victor P. Brasil
Keyword(s):  
Power Systems ◽  
Systems Analysis ◽  
Quaternion Algebra ◽  
Average Power ◽  
Time Varying ◽  
Instantaneous Power ◽  
Three Phase ◽  
Complex Power ◽  
Unbalanced Load ◽  
Unbalanced Loads

Instantaneous power theory has a central role in power systems analysis. Among mathematical settings used for the development of this theory, quaternion algebra has been used for describing electrical variables in recent works. In this context, this paper aims to describe three-phase power in a quaternion framework. We analyze quaternion power for balanced and unbalanced delta loads, comparing the expressions obtained to the usual expressions of complex power. The quaternion power expression obtained also makes it natural to introduce a decomposition of the unbalanced load in terms of a balanced component and an unbalanced load with null average power. It is also shown that delta unbalanced loads are equivalent to time-varying balanced loads. The results obtained extend the power systems theory in the quaternion domain and emphasize the advantages of using this framework.

scholarly journals Unbalanced Voltages Impacts on the Energy Performance of Induction Motors

2018 ◽  
Vol 8 (3) ◽  
pp. 1412 ◽  
Author(s):  
Enrique C. Quispe ◽  
Iván D. López ◽  
Fernando J. T. E. Ferreira ◽  
Vladimir Sousa
Keyword(s):  
Induction Motor ◽  
Induction Motors ◽  
Energy Performance ◽  
Positive Sequence ◽  
Negative Sequence ◽  
Voltage Unbalance ◽  
Three Phase ◽  
Motor Load ◽  
Sequence Parameters

<p class="Abstract">This paper presents the results of a study about the effects of unbalanced voltages on the energy performance of three-phase induction motors. The principal contribution of this paper is that presents a detailed analysis of the influence of positive and negative sequence voltage components and the angle between them on several characteristics such as: line currents, losses, efficiency and power factor under different voltage unbalanced conditions. A three-phase induction motor of 3 HP was used as a case study. The results of the investigation show that the positive sequence voltage must be considered together with the voltage unbalance factor (VUF) or percent voltage unbalance (PVU) index to evaluate the performance of the induction motor. It is also shown that the behavior of the motor load influences on the positive sequence parameters next to the voltage, while in the case of negative sequence only influences the negative sequence voltage.</p>

scholarly journals Passive Reactive Power Compensators for Improving the Sustainability of Three-Phase, Four-Wire Sinusoidal Systems Supplied by Unbalanced Voltages

2021 ◽  
Vol 13 (20) ◽  
pp. 11134
Author(s):  
Elisa Peñalvo-López ◽  
Vicente León-Martínez ◽  
Joaquín Montañana-Romeu ◽  
Javier Cárcel-Carrasco
Keyword(s):  
Carbon Dioxide ◽  
Power Systems ◽  
Carbon Dioxide Emissions ◽  
Reactive Power ◽  
Distribution Networks ◽  
Industrial Applications ◽  
Energy Losses ◽  
Capacitor Banks ◽  
Three Phase ◽  
Zero Sequence

Compensation of reactive power is necessary in power systems due to economical, energetic, and environmental reasons. Reactive power increases energy power losses and carbon dioxide emissions in distribution lines and power transformers. However, capacitor banks used in most industrial applications do not significantly reduce energy losses in lines and transformers when supply voltages and loads are unbalanced and therefore do not fully improve the sustainability of distribution networks. This fact is explained in this paper using positive-, negative-, and zero-sequence reactive power components in three-phase, four-wire sinusoidal power systems supplied with unbalanced voltages. Likewise, several devices have also been developed for the compensation of the total reactive power and, specifically, for each of its components in these power systems. Comparing the effectiveness of these reactive compensators and other well-known passive compensators as capacitor banks on the sustainability improvement of the electrical installation of an actual industry, reductions between 20% and 100% in energy losses and carbon dioxide emissions, caused by circulation of reactive currents in transformer and lines, can be expected depending on the type of compensator used.

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