A novel scheme for mitigation of line current harmonics and compensation of reactive power in three phase low voltage distribution systems

2002 ◽  
Author(s):  
M. Ashari ◽  
C.V. Nayar ◽  
S. Islam
Keyword(s):  
Distribution Systems ◽  
Reactive Power ◽  
Low Voltage ◽  
Voltage Distribution ◽  
Current Harmonics ◽  
Line Current ◽  
Three Phase

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.

scholarly journals An Alternate Representation of the Vector of Apparent Power and Unbalanced Power in Three-Phase Electrical Systems

2020 ◽  
Vol 10 (11) ◽  
pp. 3756
Author(s):  
Pedro A. Blasco ◽  
Rafael Montoya-Mira ◽  
José M. Diez ◽  
Rafael Montoya
Keyword(s):  
Nonlinear Systems ◽  
Distribution Systems ◽  
Low Voltage ◽  
Practical Case ◽  
Voltage Distribution ◽  
Efficient System ◽  
Electrical Systems ◽  
Three Phase ◽  
Unbalanced Loads ◽  
Wire System

Low-voltage distribution systems are typically unbalanced. These inefficiencies cause unbalanced powers that can significantly increase the apparent power of the system. Analysing and measuring these inefficient powers appropriately allows us to compensate for them and obtain a more efficient system. Correcting the imbalance at some nodes can worsen the rest of the system; therefore, it is essential that all nodes are analysed such that action can be taken when necessary. In most studies, the unbalanced power is measured from the modulus. Other more recent studies have proposed phasor expressions of unbalanced powers; however, in both cases, these are not enough to address the compensation of unbalanced powers in systems with unbalanced voltages. In this work, a different representation of the vector expressions for analysis of the unbalanced powers and the apparent powers of the three-phase linear systems is proposed. Additionally, these vector expressions are extended to nonlinear systems to quantify the harmonic apparent powers. These expressions have been formulated from the power of Buchholz and are valid for systems with unbalanced voltages and currents. To help understand the use of the proposed formulation, a practical case of a three-phase four-wire system with unbalanced loads and voltages is demonstrated.

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.

Development of Automatic Voltage Regulator for Low Voltage Distribution Systems

2012 ◽  
Vol 132 (5) ◽  
pp. 436-444 ◽  
Author(s):  
Katsuhiro Matsuda ◽  
Kazuhiro Horikoshi ◽  
Toshiyuki Seto ◽  
Osamu Iyama ◽  
Hiromu Kobayashi
Keyword(s):  
Distribution Systems ◽  
Low Voltage ◽  
Voltage Regulator ◽  
Voltage Distribution ◽  
Automatic Voltage Regulator
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