scholarly journals A Systematic Review of Key Challenges in Hybrid HVAC–HVDC Grids

Energies ◽  
2021 ◽  
Vol 14 (17) ◽  
pp. 5451
Author(s):  
Umar Javed ◽  
Neelam Mughees ◽  
Muhammad Jawad ◽  
Omar Azeem ◽  
Ghulam Abbas ◽  
...  
Keyword(s):  
High Voltage ◽  
Power Flow ◽  
Optimal Power Flow ◽  
Control Strategies ◽  
Frequency Control ◽  
Voltage Regulation ◽  
Load Frequency Control ◽  
Future Research ◽  
Stable Operation ◽  
Dc Voltage

The concept of hybrid high-voltage alternating current (HVAC) and high-voltage direct current (HVDC) grid systems brings a massive advantage to reduce AC line loading, increased utilization of network infrastructure, and lower operational costs. However, it comes with issues, such as integration challenges, control strategies, optimization control, and security. The combined objectives in hybrid HVAC–HVDC grids are to achieve the fast regulation of DC voltage and frequency, optimal power flow, and stable operation during normal and abnormal conditions. The rise in hybrid HVAC–HVDC grids and associated issues are reviewed in this study along with state-of-the-art literature and developments that focus on modeling robust droop control, load frequency control, and DC voltage regulation techniques. The definitions, characteristics, and classifications of key issues are introduced. The paper summaries the key insights of hybrid HVAC–HVDC grids, current developments, and future research directions and prospects, which have led to the evolution of this field. Therefore, the motivation, novelty, and the main contribution of the survey is to comprehensively analyze the integration challenges, implemented control algorithms, employed optimization algorithms, and major security challenges of hybrid HVAC–HVDC systems. Moreover, future research prospects are identified, such as security algorithms’ constraints, dynamic contingency modeling, and cost-effective and reliable operation.

scholarly journals Impact of communication time delays on combined LFC and AVR of a multi-area hybrid system with IPFC-RFBs coordinated control strategy

2021 ◽  
Vol 6 (1) ◽  
Author(s):  
C H. Naga Sai Kalyan ◽  
G. Sambasiva Rao
Keyword(s):  
Time Delays ◽  
Power Flow ◽  
Frequency Control ◽  
Dynamic Performance ◽  
Coordinated Control ◽  
Voltage Regulation ◽  
Load Frequency Control ◽  
Superior Performance ◽  
Communication Time ◽  
The Impact

AbstractIn this paper, the impact of communication time delays (CTDs) on combined load frequency control (LFC) and automatic voltage regulation (AVR) of a multi-area system with hybrid generation units is addressed. Investigation reveals that CTDs have significant effect on system performance. A classical PID controller is employed as a secondary regulator and its parametric gains are optimized with a differential evolution - artificial electric field algorithm (DE-AEFA). The superior performance of the presented algorithm is established by comparing with various optimization algorithms reported in the literature. The investigation is further extended to integration of redox flow batteries (RFBs) and interline power flow controller (IPFC) with tie-lines. Analysis reveals that IPFC and RFBs coordinated control enhances system dynamic performance. Finally, the robustness of the proposed control methodology is validated by sensitivity analysis during wide variations of system parameters and load.

scholarly journals Control Strategies of DC Microgrids Cluster: A Comprehensive Review

Energies ◽  
2021 ◽  
Vol 14 (22) ◽  
pp. 7569
Author(s):  
Zaid Hamid Abdulabbas Al-Tameemi ◽  
Tek Tjing Lie ◽  
Gilbert Foo ◽  
Frede Blaabjerg
Keyword(s):  
Power Flow ◽  
Control Strategies ◽  
Future Research ◽  
Consensus Protocol ◽  
Power Flow Control ◽  
Dc Microgrids ◽  
Significant Control ◽  
Comparative Review ◽  
Cluster A ◽  
Research Recommendations

Multiple microgrids (MGs) close to each other can be interconnected to construct a cluster to enhance reliability and flexibility. This paper presents a comprehensive and comparative review of recent studies on DC MG clusters’ control strategies. Different schemes regarding the two significant control aspects of networked DC MGs, namely DC-link voltage control and power flow control between MGs, are investigated. A discussion about the architecture configuration of DC MG clusters is also provided. All advantages and limitations of various control strategies of recent studies are discussed in this paper. Furthermore, this paper discusses three types of consensus protocol with different time boundaries, including linear, finite, and fixed. Based on the main findings from the reviewed studies, future research recommendations are proposed.

scholarly journals Load Frequency Control of Photovoltaic-Gasifier for Interconnected Two-Area Power Systems

2019 ◽  
Vol 9 (1) ◽  
pp. 2101-2105
Keyword(s):  
Power Systems ◽  
Power System ◽  
Pid Control ◽  
Pid Controller ◽  
Power Flow ◽  
Frequency Control ◽  
Load Frequency Control ◽  
Interconnected Power System ◽  
Load Frequency ◽  
Tie Line

Load frequency control (LFC) in interconnected power system of small distribution generation (DG) for reliability in distribution system. The main objective is to performance evaluation load frequency control of hybrid for interconnected two-area power systems. The simulation consist of solar farm 10 MW and gasifier plant 300 kW two-area in tie line. This impact LFC can be address as a problem on how to effectively utilize the total tie-line power flow at small DG. To performance evaluation and improve that defect of LFC, the power flow of two-areas LFC system have been carefully studied, such that, the power flow and power stability is partially LFC of small DG of hybrid for interconnected two-areas power systems. Namely, the controller and structural properties of the multi-areas LFC system are similar to the properties of hybrid for interconnected two-area LFC system. Inspired by the above properties, the controller that is propose to design some proportional-integral-derivative (PID) control laws for the two-areas LFC system successfully works out the aforementioned problem. The power system of renewable of solar farm and gasifier plant in interconnected distribution power system of area in tie – line have simulation parameter by PID controller. Simulation results showed that 3 types of the controller have deviation frequency about 0.025 Hz when tie-line load changed 1 MW and large disturbance respectively. From interconnected power system the steady state time respond is 5.2 seconds for non-controller system, 4.3 seconds for automatic voltage regulator (AVR) and 1.4 seconds for under controlled system at 0.01 per unit (p.u.) with PID controller. Therefore, the PID control has the better efficiency non-controller 28 % and AVR 15 %. The result of simulation in research to be interconnected distribution power system substation of area in tie - line control for little generate storage for grid connected at better efficiency and optimization of renewable for hybrid. It can be conclude that this study can use for applying to the distribution power system to increase efficiency and power system stability of area in tie – line.

scholarly journals Challenges and Opportunities of Load Frequency Control in Conventional, Modern and Future Smart Power Systems: A Comprehensive Review

Energies ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 2497 ◽  
Author(s):  
Hassan Alhelou ◽  
Mohamad-Esmail Hamedani-Golshan ◽  
Reza Zamani ◽  
Ehsan Heydarian-Forushani ◽  
Pierluigi Siano
Keyword(s):  
Power Systems ◽  
Control Strategies ◽  
Frequency Control ◽  
Vital Role ◽  
Load Frequency Control ◽  
Smart Power ◽  
Stable Mode ◽  
Control Loops ◽  
Load Frequency ◽  
Secondary Frequency Control

Power systems are the most complex systems that have been created by men in history. To operate such systems in a stable mode, several control loops are needed. Voltage frequency plays a vital role in power systems which need to be properly controlled. To this end, primary and secondary frequency control loops are used to control the frequency of the voltage in power systems. Secondary frequency control, which is called Load Frequency Control (LFC), is responsible for maintaining the frequency in a desirable level after a disturbance. Likewise, the power exchanges between different control areas are controlled by LFC approaches. In recent decades, many control approaches have been suggested for LFC in power systems. This paper presents a comprehensive literature survey on the topic of LFC. In this survey, the used LFC models for diverse configurations of power systems are firstly investigated and classified for both conventional and future smart power systems. Furthermore, the proposed control strategies for LFC are studied and categorized into different control groups. The paper concludes with highlighting the research gaps and presenting some new research directions in the field of LFC.

Comparison of two control strategies for VSC-MTDC with wind farm

2021 ◽  
Vol 14 ◽  
Author(s):  
Congshan Li ◽  
Pu Zhong ◽  
Ping He ◽  
Yan Liu ◽  
Yan Fang ◽  
...  
Keyword(s):  
Power Control ◽  
Control Strategy ◽  
Voltage Stability ◽  
Wind Farm ◽  
Control Strategies ◽  
Wind Farms ◽  
Active Power ◽  
Stable Operation ◽  
Active Power Control ◽  
Dc Voltage

: Two VSC-MTDC control strategies with different combinations of controllers are proposed to eliminate transient fluctuations in the DC voltage stability, resulting from a power imbalance in a VSC-MTDC connected to wind farms. First, an analysis is performed of a topological model of a VSC converter station and a VSC-MTDC, as well as of a mathematical model of a wind turbine. Then, the principles and characteristics of DC voltage slope control, constant active power control, and inner loop current control used in the VSC-MTDC are introduced. Finally, the PSCAD/EMTDC platform is used to establish an electromagnetic transient model of a wind farm connected to a parallel three-terminal VSC-HVDC. An analysis is performed for three cases of single-phase grounding faults on the rectifier and inverter sides of a converter station and of the withdrawal of the converter station on the rectifier side. Next, the fault response characteristics of VSC-MTDC are compared and analyzed. The simulation results verify the effectiveness of the two control strategies, both of which enable the system to maintain DC voltage stability and active power balance in the event of a fault. Background: The use of a VSC-MTDC to connect wind power to the grid has attracted considerable attention in recent years. A suitable VSC-MTDC control method can enable the stable operation of a power grid. Objective: The study aims to eliminate transient fluctuations in the DC voltage stability resulting from a power imbalance in a VSC-MTDC connected to a wind farm. Method: First, the topological structure and a model of a three-terminal VSC-HVDC system connected to wind farms are studied. Second, an analysis is performed of the outer loop DC voltage slope control, constant active power control and inner loop current control of the converter station of a VSC-MTDC. Two different control strategies are proposed for the parallel three-terminal VSC-HVDC system: the first is DC voltage slope control for the rectifier station and constant active power control for the inverter station, and the second is DC voltage slope control for the inverter station and constant active power for the rectifier station. Finally, a parallel three-terminal VSC-HVDC model is built based on the PSCAD/EMTDC platform and used to verify the accuracy and effectiveness of the proposed control strategy. Results: The results of simulation analysis of the faults on the rectifier and inverter sides of the system show that both strategies can restore the system to the stable operation. The effectiveness of the proposed control strategy is thus verified. Conclusion: The control strategy proposed in this paper provides a technical reference for designing a VSC-MTDC system for wind farms.

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