Voltage sag compensation strategy for unified power quality conditioner with simultaneous reactive power injection

Yang, Xu; Xiao, Xiangning; Sun, Yong; Long, Yunbo

doi:10.1007/s40565-016-0183-x

Cited by 17 publications

(4 citation statements)

References 9 publications

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“…Reactive power is linked to voltage. Therefore, in [11]- [12], the reactive power injection is used to alleviate voltage sags. The accurate assessment of voltage sags/swells can enhance the effectiveness of voltage sags/swells governance.…”

Section: Introductionmentioning

confidence: 99%

An Evaluation Method for Bus and Grid Structure Based on Voltage Sags/Swells Using Voltage Ellipse Parameters

Tian

Liu

et al. 2021

IEEE Access

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Voltage sags and swells are significant issues of power quality. In order to alleviate voltage sags and swells on sensitive loads, a method is proposed to evaluate the bus and grid structure based on voltage sags/swells using voltage ellipse parameters. The voltage matrix is established for voltage sags/swells caused by four types of short-circuit faults. The voltage matrix can be converted into a minor axis matrix and a major axis matrix using the Clarke transformation, and accordingly a voltage sag matrix and a voltage swell matrix can be obtained with the interaction between voltage sags/swells and voltage ellipse parameters. The key indicator and the vulnerability indicator of bus as well as the indicator of grid structure are defined according to the voltage sag matrix and swell matrix. The buses are sorted using the indicators proposed, and the result of bus sorting provides a basis for selecting the buses that need to be managed to alleviate voltage sags/swells. The experiment results in IEEE 30-bus system and IEEE 57-bus system show that these indicators facilitate the selection of the access point for newly-added sensitive loads, and provide a theoretical guidance to the mitigation of voltage sags and swells, and help to accomplish the planning, operation and transformation of power grid.

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Section: Introductionmentioning

confidence: 99%

An Evaluation Method for Bus and Grid Structure Based on Voltage Sags/Swells Using Voltage Ellipse Parameters

Tian

Liu

et al. 2021

IEEE Access

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“…Correspondingly, the amplitudes and directions of the power flows will be changed with the SC/PC's operation state changes. According to the phase angle difference between system output voltage (i.e., load voltage) and grid voltage, the common analysis methods of the UPQC's operation principle are as follows: (1) UPQC-P: the difference is 0 or π, the SC only transmits active powers in the forward or reverse direction [5,6]; (2) UPQC-Q: the difference is π/2, the SC only transmits reactive powers for loads [7,8]; (3) UPQC-VAmin: the difference range is 0-π/2, the SC transmits active and reactive powers at the same time. This method attempts to minimize the volt-ampere (VA) loading, thereby reducing the design cost of UPQC [9,10]; (4) UPQC-S: it has the same range of the angle difference as UPQC-VAmin, but the difference is that the SC operates at maximum capacity to enhance the UPQC's utilization [11,12].…”

Section: Introductionmentioning

confidence: 99%

Impedance Matching-Based Power Flow Analysis for UPQC in Three-Phase Four-Wire Systems

et al. 2021

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Different from the extant power flow analysis methods, this paper discusses the power flows for the unified power quality conditioner (UPQC) in three-phase four-wire systems from the point of view of impedance matching. To this end, combined with the designed control strategies, the establishing method of the UPQC impedance model is presented, and on this basis, the UPQC system can be equivalent to an adjustable impedance model. After that, a concept of impedance matching is introduced into this impedance model to study the operation principle for the UPQC system, i.e., how the system changes its operation states and power flow under the grid voltage variations through discussing the matching relationships among node impedances. In this way, the nodes of the series and parallel converter are matched into two sets of impedances in opposite directions, which mean that one converter operates in rectifier state to draw the energy and the other one operates in inverter state to transmit the energy. Consequently, no matter what grid voltages change, the system node impedances are dynamically matched to ensure that output equivalent impedances are always equal to load impedances, so as to realize impedance and power balances of the UPQC system. Finally, the correctness of the impedance matching-based power flow analysis is validated by the experimental results.

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“…The recent growth in the application of some types of loads in distribution systems such as non-linear load has resulted in a disturbance in the power system which is related to current and voltage that has translated into an area of interest for researchers [1,2]. Owing to the upgrade of the power system network, as it attained some complexity level and coupled with an increase of load, the problem of power quality has become frequently pronounced [3,4]. The normal operation of the largely sensitive load in a distributed system is affected by the voltage quality problem, which results in several economic problems with attendant adverse effects [3].…”

Section: Introductionmentioning

confidence: 99%

“…Owing to the upgrade of the power system network, as it attained some complexity level and coupled with an increase of load, the problem of power quality has become frequently pronounced [3,4]. The normal operation of the largely sensitive load in a distributed system is affected by the voltage quality problem, which results in several economic problems with attendant adverse effects [3]. The most frequently recurring disturbances in the distribution network are voltage sags and swells [5,6].…”

Section: Introductionmentioning

confidence: 99%

Voltage Dip/Swell Mitigation and Imaginary Power Compensation in Low Voltage Distribution Utilizing Improved Unified Power Quality Conditioner (I-UPQC)

Osaloni

Saha

2020

JERA

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The main purpose of this work is to introduced power quality improvement in low voltage distribution networks with the application of Improved Unified Power Quality Conditioner (I-UPQC). Ordinarily, in the normal UPQC, the series inverter handles active injection while the shunt inverter provides load imaginary power injection. However, in the case of I-UPQC, the series inverter of the UPQC performs two functions concurrently as a sag and swell compensator and assists the shunt inverter in load reactive power requirements. The reactive power sharing is achieved by the integration of the Power Angle Control (PAC) of UPQC to coordinate imaginary power-sharing between the two inverters. With the view that the series inverter produces active and reactive power, this concept is named I-UPQC. Full mathematical analysis to extend the PAC method to I-UPQC has been carried out in this work. The simulation and results produced in the MATLAB / SIMULINK environment and discussion to support the developed concept are also presented. The result from the proposed concept is confirmed by comparing the concept with operation unified power quality conditioner in steady-state.

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Voltage sag compensation strategy for unified power quality conditioner with simultaneous reactive power injection

Cited by 17 publications

References 9 publications

An Evaluation Method for Bus and Grid Structure Based on Voltage Sags/Swells Using Voltage Ellipse Parameters

An Evaluation Method for Bus and Grid Structure Based on Voltage Sags/Swells Using Voltage Ellipse Parameters

Impedance Matching-Based Power Flow Analysis for UPQC in Three-Phase Four-Wire Systems

Voltage Dip/Swell Mitigation and Imaginary Power Compensation in Low Voltage Distribution Utilizing Improved Unified Power Quality Conditioner (I-UPQC)

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