Small-signal dynamic model of a micro-grid including conventional and electronically interfaced distributed resources

2007 ◽  
Vol 1 (3) ◽  
pp. 369 ◽  
Author(s):  
F. Katiraei ◽  
M.R. Iravani ◽  
P.W. Lehn
Energies ◽  
2020 ◽  
Vol 13 (4) ◽  
pp. 1012 ◽  
Author(s):  
Sijia Wang ◽  
Xiangyu Wu ◽  
Gang Chen ◽  
Yin Xu

In recent years, ultralow-frequency oscillation has repeatedly occurred in asynchronously connected regional power systems and brought serious threats to the operation of power grids. This phenomenon is mainly caused by hydropower units because of the water hammer effect of turbines and the inappropriate Proportional-Integral-Derivative (PID) parameters of governors. In practice, hydropower and solar power are often combined to form an integrated photovoltaic (PV)-hydro system to realize complementary renewable power generation. This paper studies ultralow-frequency oscillations in integrated PV-hydro systems and analyzes the impacts of PV generation on ultralow-frequency oscillation modes. Firstly, the negative damping problem of hydro turbines and governors in the ultralow-frequency band was analyzed through the damping torque analysis. Subsequently, in order to analyze the impact of PV generation, a small-signal dynamic model of the integrated PV-hydro system was established, considering a detailed dynamic model of PV generation. Based on the small-signal dynamic model, a two-zone and four-machine system and an actual integrated PV-hydro system were selected to analyze the influence of PV generation on ultralow-frequency oscillation modes under different scenarios of PV output powers and locations. The analysis results showed that PV dynamics do not participate in ultralow-frequency oscillation modes and the changes of PV generation to power flows do not cause obvious changes in ultralow-frequency oscillation mode. Ultra-low frequency oscillations are mainly affected by sources participating in the frequency adjustment of systems.


Author(s):  
Yuqing Dong ◽  
Junpeng Ma ◽  
Shunliang Wang ◽  
Tianqi Liu ◽  
Xiang Chen ◽  
...  

Author(s):  
Santhoshkumar Thenpennaisivem ◽  
V. Senthilkumar

In this article, a hybrid technique is proposed for improving the transient and small signal response in micro grid using virtual inertia. The proposed hybrid technique is the combined execution of both the emperor penguin optimizer (EPO) and butterfly optimization algorithm (BOA), and hence it is called EPOBOA technique. The major objective of the EPOBOA technique is to “optimize the control parameters to regulate the changes occurred in the grid parameter such as voltage and frequency based on the variations of inertia”. Here, the EPO is executed to modify the parameters of virtual synchronous generator units to achieve the objective function. The searching behaviour of the EPO is adapted by using the hunting behaviour of BOA. The proposed technique is executed in MATLAB/Simulink work site, and the experimental results are analyzed under three test cases: normal condition, irradiation change condition, and load change condition. The performance of the proposed technique is compared with different existing techniques and the calculated frequency deviation index of the proposed technique in all the cases is 0.0051, 0.0045, and 0.0047 and found to be very optimal compared with existing methods. Overall, the experimental outcomes show that the proposed EPOBOA method is more efficient and confirm its ability to solve the issues.


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