Unbalanced Voltage/Power Control in Bipolar DC Distribution Grids Using Power Flow Controller

Liao, Jianquan; Qin, Zian; Purgat, Pavel; Zhou, Niancheng; Wang, Qianggang; Bauer, Pavol

doi:10.1109/isie45063.2020.9152454

Cited by 8 publications

(4 citation statements)

References 17 publications

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“…In terms of devices, two common approaches can be used to mitigate the voltage unbalance, namely source-and load-side approaches. A typical source-side approach involves configuring the voltage balancer at the exit of the AC/DC rectifier [6], using the self-balancing isolated DC-DC converter [7], configuring the power flow controller at the head of the line [8], and using a three-level DC converter to balance the voltage [9]. These approaches are effective in controlling the local voltage, but their effectiveness is weakened for other nodes far from the controlled ones.…”

Section: A Indices and Sets I J K Qmentioning

confidence: 99%

Multi-objective Day-ahead Polarity Switching Optimization for Voltage Unbalance in Bipolar DC Distribution Networks

Huang¹,

Wang²,

Chen³

et al. 2023

Journal of Modern Power Systems and Clean Energy

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Bipolar direct current (DC) distribution networks can effectively improve the connection flexibility for renewable generations and loads. In practice, concerns regarding the potential voltage unbalance issue of the distribution networks and the frequency of switching still remain. This paper proposes a day-ahead polarity switching strategy to reduce voltage unbalance by optimally switching the polarity of renewable generations and loads while minimizing the switching times simultaneously in the range of a full day. First, a multi-objective optimization model is constructed to minimize the weighted sum of voltage unbalance factors and the sum of number of switching actions in the day based on the power flow model. Second, a two-step solution strategy is proposed to solve the optimization model. Finally, the proposed strategy is validated using 11-node and 34-node distribution networks as case studies, and a switching and stabilizing device is designed to enable unified switching of renewable generations and loads. Numerical results demonstrate that the proposed strategy can effectively reduce the switching times without affecting the improvement of voltage balance.

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Section: A Indices and Sets I J K Qmentioning

confidence: 99%

Multi-objective Day-ahead Polarity Switching Optimization for Voltage Unbalance in Bipolar DC Distribution Networks

Huang¹,

Wang²,

Chen³

et al. 2023

Journal of Modern Power Systems and Clean Energy

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show abstract

“…Higher complexity and higher cost 2. Cannot regulate the unbalanced voltage of the end nodes adequately Power flow controller [23] For the switching device, the authors of [20] proposed a method to regulate the unbalanced voltage and current. The serial automatic commutation switch (ACS) was applied in the control method to adjust the power polarity of the DC loads.…”

Section: Switching Devicementioning

confidence: 99%

“…However, compared with the two-level converter, the three-level converter has higher complexity and a higher cost. In [23], a strategy to realize power flow control (PFC) of the DC distribution network and balance of the positive and negative voltage or power is proposed. The application of series-parallel PFC in a bipolar DC distribution system is studied.…”

Section: Switching Devicementioning

confidence: 99%

Coordinated Control of Voltage Balancers for the Regulation of Unbalanced Voltage in a Multi-Node Bipolar DC Distribution Network

2022

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In a bipolar DC distribution network, the unbalanced load resistance, line resistance and renewable energy source will cause an unbalanced current for each node of the neutral line and lead to its unbalanced voltage. This is a unique power quality problem of bipolar DC distribution networks, which will increase the power loss in the network and lead to overcurrent protection of the neutral line in serious cases. A voltage balancer can be adopted to suppress the unbalanced voltage and current. However, the existing literature does not consider the consistent application of multiple voltage balancers in a multi-node bipolar DC distribution network. This paper creatively proposes a consensus control topology combining primary control and secondary control in a radial multi-node bipolar DC distribution network with voltage balancers. In this paper, the formulas for the positive and negative current and duty cycle of a bipolar DC distribution network with voltage balancers are derived, and improved voltage balancer modeling based on a consensus algorithm is built. The radial multi-node bipolar DC distribution network is established in MATLAB/Simulink. The simulation results compare the consensus control with the traditional droop control and verify the effectiveness of the new control structure with voltage balancers.

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“…Compared with a unipolar DC distribution grid, the structure of a bipolar DC distribution grid system adds a DC bus, which can provide interfaces of multiple voltage levels for the side of the power supply, facilitating different loads to connect to the grid through the interfaces of appropriate voltage levels and meeting the requirements of different loads. However, the presence of coupling between the positive and negative buses, the asymmetric distribution of the electrical parameters of the system, and the imbalance of the loads cause the imbalance of the output voltages between the poles and affects the quality of the power supply in the bipolar DC distribution grid [3]. In [4], a decoupled equivalent model for a bipolar DC distribution grid with asymmetric output voltage is deduced based on the DC symmetrical component method, which decomposes the voltages of positive and negative buses into common mode and differential mode (i.e., symmetric components) and obtains the interaction between power transmission of positive and negative poles.…”

Section: Introductionmentioning

confidence: 99%

Research on Output Voltage Self-Balance Control Method of Bipolar DC Distribution Grid for Renewable Energy Consumption

Wen

Yang

Han

et al. 2023

J. Phys.: Conf. Ser.

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Changes in the positive and negative DC loads of bipolar DC distribution grid cause the voltages of DC buses to deviate from the rated value, resulting in additional losses due to unbalanced current and affecting the reliable operation of the distribution grid. This paper proposes an output voltage self-balance control method based on a neutral-point-calmed triple active bridge (NPC-TAB) converter in a bipolar DC distribution grid. First, the topology and operating principle of NPC-TAB are introduced. Then the power model of the topology is deduced based on the phasor method. Based on the above analysis, an output voltage self-balance control method is proposed with the minimization of reactive power to achieve the self-balance of output voltage while controlling the minimization of reactive power of the converter. Finally, the simulation model is established in MATLAB/Simulink to verify the effectiveness of the optimal control method.

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Unbalanced Voltage/Power Control in Bipolar DC Distribution Grids Using Power Flow Controller

Cited by 8 publications

References 17 publications

Multi-objective Day-ahead Polarity Switching Optimization for Voltage Unbalance in Bipolar DC Distribution Networks

Multi-objective Day-ahead Polarity Switching Optimization for Voltage Unbalance in Bipolar DC Distribution Networks

Coordinated Control of Voltage Balancers for the Regulation of Unbalanced Voltage in a Multi-Node Bipolar DC Distribution Network

Research on Output Voltage Self-Balance Control Method of Bipolar DC Distribution Grid for Renewable Energy Consumption

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