scholarly journals Characteristic Analysis and Indexing of Multimachine Transient Stabilization Using Virtual Synchronous Generator Control

Energies ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 366
Author(s):  
Yuko Hirase ◽  
Kazusa Uezaki ◽  
Dai Orihara ◽  
Hiroshi Kikusato ◽  
Jun Hashimoto

As distributed power sources via grid-connected inverters equipped with functions to support system stabilization are being rapidly introduced, individual systems are becoming more complex, making the quantification and evaluation of the stabilizing functions difficult. Therefore, to introduce distributed power sources and achieve stable system operation, a system should be reduced to a necessary but sufficient size in order to enable the quantification of its behavior supported by transient theory. In this study, a system in which multiple distributed power supplies equipped with virtual synchronous generator control are connected is contracted to a two-machine system: a main power supply and all other power supplies. The mechanical torque of each power supply is mathematically decomposed into inertia, damping, synchronization torques, and the governor effect. The system frequency deviations determined by these elements are quantitatively indexed using MATLAB/Simulink. The quantification index displayed in three-dimensioned graphs illustrates the relationships between the various equipment constants of the main power supply, the control variables of the grid-connected inverter control, and the transient time series. Moreover, a stability analysis is performed in both the time and frequency domains.

Author(s):  
Xin Shen ◽  
Hongchun Shu ◽  
Min Cao ◽  
Nan Pan ◽  
Junbin Qian

In distribution networks with distributed power supplies, distributed power supplies can also be used as backup power sources to support the grid. If a distribution network contains multiple distributed power sources, the distribution network becomes a complex power grid with multiple power supplies. When a short-circuit fault occurs at a certain point on the power distribution network, the size, direction and duration of the short-circuit current are no longer single due to the existence of distributed power, and will vary with the location and capacity of the distributed power supply system. The change, in turn, affects the current in the grid, resulting in the generation and propagation of additional current. This power grid of power electronics will cause problems such as excessive standard mis-operation, abnormal heating of the converter and component burnout, and communication system failure. It is of great and practical significance to study the influence of distributed power in distributed power distribution networks.


2021 ◽  
Vol 2021 ◽  
pp. 1-8
Author(s):  
Shijie Cui ◽  
Peng Zeng ◽  
Zhongfeng Wang ◽  
Yue Zuo

Because the distributed power supply is connected to the distribution network, its structure has also changed the original traditional method. The original single power supply method was originally used. The network provided is a radial network and it is connected to the distributed power supply. Later, it became a structure with small- and medium-sized power supplies inside, and its network power supply became dual or multiple power supplies. Such a structural change affected the coordination of power distribution protection devices, which would impose current on the distribution network. Protection has a negative impact. This paper aims to study the adaptive current protection technology of distribution network with distributed power based on local information. On the basis of analyzing the characteristics of distributed power, the classification of distributed power, and the operation mode of distributed power, according to the access of IIDG, as well as different influences of relay protection of distribution network, an improved protection scheme with adaptive current quick-break protection as the main protection is proposed, so that different fault characteristics of the distribution network have different setting values, and then simulation experiments are carried out on this scheme. The experimental results show that the setting value of three-phase short-circuit fault proposed in this paper can well protect the protection range, which is larger than the traditional protection setting and self-adaptive setting.


Symmetry ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 1697 ◽  
Author(s):  
Lingling Li ◽  
Hengyi Li ◽  
Ming-Lang Tseng ◽  
Huan Feng ◽  
Anthony S. F. Chiu

This study constructs a novel virtual synchronous generator system based on a transfer function, and optimizes the parameters of the model by using the improved whale algorithm to improve the frequency control ability of virtual synchronous generator. Virtual synchronous generator technology helps to solve the problem that the integration of large-scale renewable energy generation into the power system leads to the deterioration of system frequency stability. It can maintain the symmetry of grid-connected scale and system stability. The virtual synchronous generator technology makes the inverter to have the inertia and damping characteristics of a synchronous generator. The inverter has the inertia characteristics and damps to reduce the frequency instability of high penetration renewable energy power system. The improved whale algorithm is efficient to find the best combination of control parameters and the effectiveness of the algorithm is verified by microgrid and power system. The results show that the proposed frequency coordination control scheme suppresses the frequency deviation of power system and keep the system frequency in a reasonable range.


2018 ◽  
Vol 16 ◽  
pp. 03004 ◽  
Author(s):  
Lucjan Setlak ◽  
Rafał Kowalik

Based on the mathematical model of synchronous electric machine, basing on permanent magnets, presented in this paper, the key importance of alternator AC power sources in the form of generator (for conventional aircraft) and in the form of integrated unit starter/AC synchronous generator S/G AC (with respect to advanced aircraft concept in the field of more/all electric power MEA/AEA) was highlighted. In addition, through the analysis and selected simulations of the power supply system of a modern aircrafts, sources of onboard electrical energy (synchronous generator, integrated unit starter/AC generator) were located in board autonomic power system ASE (EPS, PES). Key components of this system are the electro-energetic power system EPS and the energo-electronic power system PES. Additionally, the analysis and exemplary simulations of key electricity sources based on mathematical models have contributed to highlighting the main practical applications in line with the trend of a more electric aircraft.


2012 ◽  
Vol 132 (4) ◽  
pp. 371-380 ◽  
Author(s):  
Yuko Hirase ◽  
Kazuhiro Abe ◽  
Kazushige Sugimoto ◽  
Yuji Shindo

Author(s):  
Yevhen Vereshchago ◽  
Vitalii Kostiuchenko

Purpose. Creation of virtual blocks and simulation laboratory stands for the study and comprehensive research of the dynamic properties of welding power supplies. Methodology. Review of literary sources on the subject, simulation modeling of electromagnetic processes in the MATLAB software environment, comparative analysis of obtained and available data. Findings. The comparative analysis of means of modeling of power sources of a welding arc is executed. One of the main parameters by which the environments were compared is functionality. Among the considered simulators, Simulink of the MATLAB software environment is the most effective one in the considered systems modeling. Using special features, its user can not only simulate, but also analyze the operation of the over time installation. Mathematical and functional models of welding arc power supplies were built using SimPowerSystems elements and blocks from the Simulink library with the involvement of the MATLAB system itself, which significantly expands the possibilities for such systems modeling. Mathematization of certain processes to some extent shows the level of reliability of the results and the degree of their scientific development. The developed models act as a laboratory, which allows you to set and explore any modes and characteristics. Numerical experiments and comparative analysis of numerical and field experiments are given. Experimental verification of the obtained results on specific examples showed the relevance of the problem and the correctness of its solution. Further research is related to the expansion of the range of simulated power sources of the electric arc, a comprehensive study of their dynamic properties and basic characteristics, experimental verification of the developed models, as well as comparative analysis and development of recommendations for model improvement. Originality. The method of circuit modeling of general-purpose electrical and electronic circuits was further developed by extending it to a new class of objects - the power supply system of electrical installations. Practical value. Construction of mathematical and functional models of complex systems with the involvement of MATLAB allows to take into account their main features, significantly expands the possibilities for modeling, study and research of power supplies. Based on the proposed approach, simulation laboratory stands of specific power supplies were developed and built, which allow to set and study any modes and characteristics.


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