scholarly journals Power Flow Control Strategy and Reliable DC-Link Voltage Restoration for DC Microgrid under Grid Fault Conditions

2019 ◽  
Vol 11 (14) ◽  
pp. 3781 ◽  
Author(s):  
Thanh Van Nguyen ◽  
Kyeong-Hwa Kim
Keyword(s):  
Flow Control ◽  
Control Strategy ◽  
Power Flow ◽  
Control Mode ◽  
Abnormal Behavior ◽  
Power Balance ◽  
Dc Microgrid ◽  
Power Flow Control ◽  
Restoration Algorithm ◽  
System Power

In this paper, an effective power flow control strategy (PFCS) based on the centralized control method and a reliable DC-link voltage (DCV) restoration algorithm for a DC microgrid (DCMG) under grid fault conditions are proposed. Considering the relationship of supply-demand power and the statuses of system units, thirteen operating modes are presented to ensure the power balance in DCMG under various conditions. In the PFCS, the battery charging/discharging procedure is implemented considering the battery power limit to avoid overheating and damage. Moreover, load shedding and load reconnection algorithms are presented to maintain the system power balance, even in critical cases. To prevent the system power imbalance in DCMG caused by the delay of grid fault detection, a reliable DCV restoration algorithm is also proposed in this paper. In the proposed scheme, as soon as abnormal behavior of the DCV is detected, the battery or wind power generation system instantly enters a local emergency control mode to restore the DCV rapidly to the nominal value, regardless of the control mode assigned from the central controller. Comprehensive simulations and experiments based on the DCMG testbed are carried out to prove the effectiveness of the PFCS and the proposed DCV restoration algorithm.

scholarly journals Improved power flow control strategy of the hybrid AC/DC microgrid based on VSM

2019 ◽  
Vol 13 (1) ◽  
pp. 81-91 ◽  
Author(s):  
Ziwen Liu ◽  
Shihong Miao ◽  
Zhihua Fan ◽  
Junyao Liu ◽  
Qingyu Tu
Keyword(s):  
Flow Control ◽  
Control Strategy ◽  
Power Flow ◽  
Dc Microgrid ◽  
Power Flow Control

scholarly journals Structural Condition for Controllable Power Flow System Containing Controllable and Fluctuating Power Devices

Energies ◽  
2020 ◽  
Vol 13 (7) ◽  
pp. 1627 ◽  
Author(s):  
Saher Javaid ◽  
Mineo Kaneko ◽  
Yasuo Tan
Keyword(s):  
Power System ◽  
Flow Control ◽  
Power Flow ◽  
Flow System ◽  
Power Balance ◽  
Power Demand ◽  
Power Devices ◽  
Power Sources ◽  
Power Flow Control ◽  
Power Fluctuations

This paper discusses a structural property for a power system to continue a safe operation under power fluctuation caused by fluctuating power sources and loads. Concerns over global climate change and gas emissions have motivated development and integration of renewable energy sources such as wind and solar to fulfill power demand. The energy generated from these sources exhibits fluctuations and uncertainty which is uncontrollable. In addition, the power fluctuations caused by power loads also have the same consequences on power system. To mitigate the effects of uncontrollable power fluctuations, a power flow control is presented which allocates power levels for controllable power sources and loads and connections between power devices. One basic function for the power flow control is to balance the generated power with the power demand. However, due to the structural limitations, i.e., the power level limitations of controllable sources and loads and the limitation of power flow channels, the power balance may not be achieved. This paper proposes two theorems about the structural conditions for a power system to have a feasible solution which achieves the power balance between power sources and power loads. The discussions in this paper will provide a solid theoretical background for designing a power flow system which proves robustness against fluctuations caused by fluctuating power devices.

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