Part 1: Decomposition of the Load’s Current in Three-phase Four-wire Systems Supplied with Asymmetrical Sinusoidal Voltage Following Currents’ Physical Components Theory

2020 ◽  
Vol 11 ◽  
pp. 34-42
Author(s):  
Zbigniew SOLJAN ◽  
Keyword(s):  
Single Phase ◽  
Low Voltage ◽  
Supply Voltage ◽  
Sinusoidal Voltage ◽  
Power Equation ◽  
Three Phase ◽  
Unbalanced Voltage ◽  
Wire System ◽  
Phase Asymmetry ◽  
Physical Components

Electricity receivers in low-voltage networks are mainly single-phase loads, which, when grouped within a given consumer, create a three-phase load. Such a replacement three-phase load works in a four-wire system. Besides, under real conditions, the supply voltage has some amplitude and phase asymmetry. Voltage unbalances, load's imbalances are issues that not simultaneously included in the power equation in four-wire systems. This article eliminates the limitations of electrical engineering in this area by deriving the power equation for three-phase loads supplied with unbalanced voltage.

Part 2: Reactive Compensation of the Linear Load in Three-Phase Four-Wire Systems Supplied with Asymmetrical Sinusoidal Voltage Following Currents’ Physical Components Theory

2020 ◽  
Vol 11 (4(42)2020) ◽  
pp. 52-64
Author(s):  
Zbigniew SOLJAN ◽  
Keyword(s):  
Single Phase ◽  
Supply Voltage ◽  
Industrial Plant ◽  
Sinusoidal Voltage ◽  
Home Office ◽  
Reactive Compensation ◽  
Load Imbalance ◽  
Power Equation ◽  
Linear Load ◽  
Three Phase

Four-wire systems are the most common ones in everyday life. Electrical installations within the home, office, or industrial plant are mostly four-wire installations. Receivers connected to such a system are mainly single-phase loads, which from the power connection are an unbalanced three-phase load. Apart from, the load imbalance, the supply voltage also has some asymmetry. Voltage asymmetry, load imbalance, the design of reactance compensators are issues that were not simultaneously included in the power equation in fourwire systems. This article presents the mathematical fundamentals of the construction of reactance compensators operating in voltage asymmetry.

Implementation of Single-Phase Two-Switch Midpoint Unidirectional Multilevel Converter System

2018 ◽  
Vol 19 (4) ◽  
Author(s):  
Peethala Rajiv Roy ◽  
P. Parthiban ◽  
B. Chitti Babu
Keyword(s):  
Single Phase ◽  
Pulse Width Modulation ◽  
Low Voltage ◽  
Supply Voltage ◽  
Harmonic Distortion ◽  
Input Voltage ◽  
Open Loop ◽  
Current Control ◽  
Control Technique ◽  
Control Scheme

Abstract This paper deals with implementation of a single-phase three level converter system under low voltage condition. The frequency of the switches is made constant and involves change in ${t_{on}}$ and ${t_{off}}$ duration. For this condition the pulse width modulation control scheme for a single phase three level rectifier is developed to improve the power quality. The hysteresis current control technique is adopted to bring forth three-level PWM on the dc side of the bridge rectifier and to achieve high power factor and low harmonic distortion. Based on the proposed control scheme, the line current is driven to follow the sinusoidal current command which is in phase with the supply voltage. By using three-level voltage pattern the blocking voltage of each power device is clamped to half of the dc link voltage. The simulation and experimental results of 20W converter under low input voltage condition are shown to verify the circuit performance. Open loop simulation and hardware tests are implemented by applying a low voltage of 15 V(rms) on the input side.

Experimental Analysis on the Operating Performance of Induction Motor with Unbalance Power Supply Conditions

2014 ◽  
Vol 635-637 ◽  
pp. 1404-1407
Author(s):  
Yuan Xing Zhang ◽  
Fei Li ◽  
Ya Li Shen ◽  
Lei Juan Yang ◽  
Jie Li ◽  
...  
Keyword(s):  
Induction Motor ◽  
Power Supply ◽  
Power Efficiency ◽  
Single Phase ◽  
Reactive Power ◽  
Phase Voltage ◽  
Three Phase ◽  
Unbalanced Voltage ◽  
Negative Sequence Current ◽  
Domestic Appliances

Problems of power quality have been increasingly concerned by the researchers, as the domestic appliances we are usually used are single-phase load, which mainly causes the unbalance of three-phase voltage of power supply. If the induction motor is supplied by three-phase unbalanced voltage, the currents, active and reactive power, efficiency, and losses are affected as the negative-sequence current appears, this paper is emphasized on the induction motor’s characteristics when its’ power supply is three-phase unbalanced voltage by experimental research.

Maintenance of Three-phase Load Voltage during Single Phase Auto Reclosing in Medium Voltage Radial Distribution Lines

2011 ◽  
Vol 12 (4) ◽  
Author(s):  
Kartik Prasad Basu ◽  
Moley Kutty George
Keyword(s):  
Radial Distribution ◽  
Distribution System ◽  
Single Phase ◽  
Dead Time ◽  
Low Voltage ◽  
Radial Distribution System ◽  
Load Voltage ◽  
Medium Voltage ◽  
Distribution Lines ◽  
Three Phase

Most faults in medium voltage (MV) distribution lines are temporary line to ground (LG) faults. Three-phase auto reclosing (TPAR) is commonly used to remove this fault with temporary disconnection of all the phases. Multi-shot single-phase auto reclosing (SPAR) may also be used to remove the LG fault. But it produces highly unbalanced and low voltage across the load during the reclosure dead time. It is proposed to connect a zigzag winding grounding transformer at the load bus to maintain the 3-phase load voltage when one phase opens during the SPAR. With low value of grounding resistance the 3-phase voltage during the SPAR dead time becomes approximately balanced. Directional over current relays may be used for the protection. Analysis of a MV radial distribution system having a zigzag transformer connected to the remotest load bus is presented with the computation of voltages during the dead time of SPAR.

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.

scholarly journals Asymmetric Compensation of Reactive Power Using Thyristor-Controlled Reactors

Symmetry ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 880
Author(s):  
Martynas Šapurov ◽  
Vytautas Bleizgys ◽  
Algirdas Baskys ◽  
Aldas Dervinis ◽  
Edvardas Bielskis ◽  
...  
Keyword(s):  
Experimental Test ◽  
Single Phase ◽  
Test Bench ◽  
Reactive Power ◽  
Low Voltage ◽  
And Topology ◽  
Three Phase ◽  
Thyristor Controlled Reactor ◽  
Utility Grid ◽  
Experimental Test Bench

The thyristor-controlled reactor (TCR) compensator for smooth asymmetric compensation of reactive power in a low-voltage utility grid is proposed in this work. Two different topologies of compensator were investigated: topology based on a single-cored three-phase reactor and topology with separate reactors for every phase. The investigation of the proposed TCR compensator was performed experimentally using a developed experimental test bench for 12 kVAr total reactive power. The obtained results show that employment of separate reactors for every phase allows us to control the reactive power in every phase independently, and that the TCR compensator with three single-phase reactors is suitable for smooth and asymmetric compensation of reactive power in a low-voltage utility grid.

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