Reactive Power Limits of Single-Phase and Three-Phase DC-Link VSC STATCOMs under Negative-Sequence Voltage and Current

2021 ◽  
Author(s):  
Iosu Marzo ◽  
Jon Andoni Barrena ◽  
Alain Sanchez-Ruiz ◽  
Gonzalo Abad ◽  
Ignacio Muguruza
Keyword(s):  
Single Phase ◽  
Reactive Power ◽  
Negative Sequence ◽  
Three Phase ◽  
Power Limits

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.

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.

Study on a Novel Three-Phase Two-Leg Active Inverter for Electrified Railway

2015 ◽  
Vol 734 ◽  
pp. 868-872
Author(s):  
Yan Ping Sun ◽  
Mo Zhou ◽  
Guo Wang
Keyword(s):  
Simulation Model ◽  
Reactive Power ◽  
Control Method ◽  
Electric Energy ◽  
Negative Sequence ◽  
Active Elements ◽  
Three Phase ◽  
Electrified Railway ◽  
The Cost ◽  
And Control

A novel topology circuit of active compensation was discussed to be used to manage negative sequence caused by locomotive load in electrified railway. The main circuit used a three-phase two-leg compensator as active elements of shunt hybrid active compensator topology. The number of switch device in this topology was reduced by comparing with three-phase full-bridge active inverter and the cost was lower. The simulation model was developed with SIMULINK. The simulating results indicates that the shunt hybrid active compensator can restrain the problem of negative sequence which generated by locomotive load, and reduces the effect of reactive power, negative sequence, improves electric energy quality and verifies the correctness of the proposed structure and control 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.

Analysis of Current Optimization Method on Compensation

2014 ◽  
Vol 668-669 ◽  
pp. 665-668
Author(s):  
Bin Su ◽  
Shun Tao ◽  
Xiang Ning Xiao ◽  
Tian Cai Wei
Keyword(s):  
Single Phase ◽  
Reactive Power ◽  
Rapid Development ◽  
Optimization Method ◽  
Simulation Studies ◽  
Three Phase ◽  
Optimal Current ◽  
Definition Of ◽  
Power Electronic Technology ◽  
Mathematical Derivation

Nowadays, with the rapid development of industrial technology especially the power electronic technology, harmonic and reactive power problems are becoming severer. In sinusoidal conditions, there are no controversies on the definition of power quantities. In nonsinusoidal circuits, the traditional definition of active power is still applicable while the definitions of reactive power and apparent power are in controversy. Based on an optimization current decomposing method, this paper derives the expressions of optimal current and compensating current in a single-phase and a three-phase circuit by constructing a Lagrange functions. Based on simulation studies, the compensating effect of the optimization method is analyzed and shown; it can noticeably improve the efficiency of energy transfer in circuit. The paper presents all mathematical derivation of the method and verifies the results based on simulation.

scholarly journals Reactive Power Compensation and Imbalance Suppression by Star-Connected Buck-Type D-CAP

Energies ◽  
2019 ◽  
Vol 12 (10) ◽  
pp. 1914 ◽  
Author(s):  
Xiaosheng Wang ◽  
Ke Dai ◽  
Xinwen Chen ◽  
Xin Zhang ◽  
Qi Wu ◽  
...  
Keyword(s):  
Control Strategy ◽  
Reactive Power ◽  
Reactive Power Compensation ◽  
Positive Sequence ◽  
Negative Sequence ◽  
Type D ◽  
Load Imbalance ◽  
Three Phase ◽  
Unbalanced Load ◽  
Line Loss

Reactive power and negative-sequence current generated by inductive unbalanced load will not only increase line loss, but also cause the malfunction of relay protection devices triggered by a negative-sequence component in the power grid, which threatens the safe operation of the power system, so it is particularly important to compensate reactive power and suppress load imbalance. In this paper, reactive power compensation and imbalance suppression by a three-phase star-connected Buck-type dynamic capacitor (D-CAP) under an inductive unbalanced load are studied. Firstly, the relationship between power factor correction and imbalance suppression in a three-phase three-wire system is discussed, and the principle of D-CAP suppressing load imbalance is analyzed. Next, its compensation ability for negative-sequence currents is determined, which contains theoretical and actual compensation ability. Then an improved control strategy to compensate reactive power and suppress imbalance is proposed. If the load is slightly unbalanced, the D-CAP can completely compensate the reactive power and negative-sequence currents. If the load is heavily unbalanced, the D-CAP can only compensate the positive-sequence reactive power and a part of the negative-sequence currents due to the limit of compensation ability. Finally, a 33 kVar/220 V D-CAP prototype is built and experimental results verify the theoretical analysis and control strategy.

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