scholarly journals Robust Optimal Allocation of Decentralized Reactive Power Compensation in Three-Phase Four-Wire Low-Voltage Distribution Networks Considering the Uncertainty of Photovoltaic Generation

Energies ◽  
2019 ◽  
Vol 12 (13) ◽  
pp. 2479 ◽  
Author(s):  
Shunjiang Lin ◽  
Sen He ◽  
Haipeng Zhang ◽  
Mingbo Liu ◽  
Zhiqiang Tang ◽  
...  
Keyword(s):  
Single Phase ◽  
Optimal Allocation ◽  
Reactive Power ◽  
Low Voltage ◽  
Reactive Power Compensation ◽  
Optimization Models ◽  
Voltage Distribution ◽  
Uncertain Variables ◽  
Three Phase ◽  
Voltage Deviation

Due to the unbalanced three-phase loads, the single-phase distributed photovoltaic (PV) integration, the long feeders, and the heavy loads in a three-phase four-wire low voltage distribution network (LVDN), the voltage unbalance factor (VUF), the network loss and the voltage deviation are relatively high. Considering the uncertain fluctuation of the PV output and the load power, a robust optimal allocation of decentralized reactive power compensation (RPC) devices model for a three-phase four-wire LVDN is proposed. In this model, the uncertain variables are described as box uncertain sets, the three-phase simultaneous switching capacity and single-phase independent switching capacity of the RPC devices are taken as decision variables, and the objective is to minimize the total power loss of the LVDN under the extreme scenarios of uncertain variables. The bi-level optimization method is used to transform the robust optimization model with uncertain variables into bi-level deterministic optimization models, which could be solved alternately. The nonlinear programming solver IPOPT in the mature commercial software GAMS is adopted to solve the upper and lower deterministic optimization models to obtain a robust optimal allocation scheme of decentralized RPC devices. Finally, the simulation results for an actual LVDN show that the obtained decentralized RPC scheme can ensure that the voltage deviation and the VUF of each bus satisfied the secure operation requirement no matter how the PV output and load power changed within their own uncertain sets, and the network loss could be effectively reduced.

Research on Methods of Reactive Compensation for Unbalanced Current in Three-Phase Four-Wire Low-Voltage Distribution System

2011 ◽  
Vol 347-353 ◽  
pp. 1156-1160
Author(s):  
Xue Ling Zhu ◽  
Wen Si Cao ◽  
Xiao Ming Zhou
Keyword(s):  
Distribution System ◽  
Reactive Power ◽  
Low Voltage ◽  
Neutral Current ◽  
Reactive Power Compensation ◽  
Current Phase ◽  
Voltage Distribution ◽  
Phase Current ◽  
Reactive Compensation ◽  
Three Phase

Different condition of unbalanced current of three-phase four-wire low-voltage distribution system is analysed in this paper. The model of unbalanced reactive power compensation is built which is fit for the three-phase four-wire system ,Using phase-to-phase or phase-to-earth capacitance or inductance can transfer active power. Control the neutral current to be zero and three-phase current balanced by means of reactive power compensation. A compensating phase judgment approach is presented, the mathematic model of calculating phase current, phase compensating capacity line current and line-to-line compensating capacity is gave. Simulation result of physical system shows that the neutral current can be controlled to be zero and the phase current balanced. It substantiate that this compensation method is valid and optimize the operation condition of loads.

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.

The Research of Unbalanced Three-Phase Adjustment in Distribution Network

2012 ◽  
Vol 263-266 ◽  
pp. 649-654
Author(s):  
Yan Wei Zheng ◽  
Zhong Hai Bai ◽  
Zhi Quan Feng
Keyword(s):  
Power Quality ◽  
Single Phase ◽  
Low Voltage ◽  
Distribution Network ◽  
Voltage Distribution ◽  
Phase Adjustment ◽  
Adjustment Strategy ◽  
Three Phase ◽  
Network Losses

To balance three-phase loads in distribution network with abundant of single-phase loads, the idea of three-phase adjustment and wiring method is proposed in this paper. Three-phase adjustment controller is designed, and the least load adjustment strategy is proposed, which can adjust the three-phase load to roughly balance automatically. The system can solve the serious three-phase unbalance problem of the lines with single-phase load, which may instead of capacitive compensation in low voltage distribution network. It can improve power quality and reduce network losses.

scholarly journals Configuration of smart phase-swapping switches in low-voltage distribution systems based on sequenced participation indices

2020 ◽  
Vol 53 (7-8) ◽  
pp. 1159-1170
Author(s):  
Lixia Cao ◽  
Guoliang Feng ◽  
Xingong Cheng ◽  
Luhao Wang
Keyword(s):  
Distribution Systems ◽  
Single Phase ◽  
Low Voltage ◽  
Economic Benefits ◽  
Voltage Distribution ◽  
Practical Applications ◽  
Three Phase ◽  
Participation Index ◽  
Configuration Problem ◽  
High Phase

The smart phase-swapping switches are used to rapidly change the phases of single-phase loads online in low-voltage distribution systems. They can reduce the three-phase imbalance indices. However, the effectiveness of phase-swapping operations is determined by not only the control strategy but also by the quantity and locations of smart phase-swapping switches. In this paper, a configuration method is proposed to determine the preferable quantity and locations of smart phase-swapping switches with considerations of economic benefits and operational requirements. Based on historical load information, the active and reactive powers of the loads are used to formulate the current imbalance index. The configuration problem is modeled as a multiobjective optimization that minimizes the current imbalance indices of all nodes and phase-swapping operations. The problem is solved by the particle swarm optimization algorithm to obtain the phase-swapping participation index of each single-phase load. The loads with high phase-swapping participation indices are preferably equipped with smart phase-swapping switches. The simulation results verify that the proposed method is effective and easy to be implemented in practical applications.

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