Placement of virtual inertia from HVDC terminals based on a frequency deviation index

Abstract The International Electrotechnical Commission introduced the concepts of exposure index (EI), target exposure index (EIT) and deviation index (DI) to manage and optimize patient dose in real time. In this study, we have proposed an appropriate method for setting the EIT based on the Korean national diagnostic reference levels (DRLs). Furthermore, we evaluated the use of clinical EI, EIT and DI as tools for patient dose optimization in clinical environments by observing the changes in DI with those in EIT. According to the Korean national exposure conditions, we conducted experiments on three representative radiographic examinations (chest posterior–anterior, lateral and abdomen anterior–posterior) of clinical environments. As the exposure conditions and DRLs varied, the clinical EI, EIT and DI also varied. These results reveal that the clinical EI, EIT and DI can be used as tools for optimizing the patient dose if EIT is periodically and properly updated.

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Stabilization of Power System by Virtual Inertia Control of Adjustable Speed Synchronous Condenser

2021 2nd International Conference on Robotics, Electrical and Signal Processing Techniques (ICREST) ◽

10.1109/icrest51555.2021.9331035 ◽

2021 ◽

Author(s):

Kazuya Matsuda ◽

Faramarz Alsharif ◽

Atsushi Umemura ◽

Rion Takahashi ◽

Junji Tamura ◽

...

Keyword(s):

Power System ◽

Synchronous Condenser ◽

Adjustable Speed ◽

Virtual Inertia ◽

Inertia Control

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Nonlinear Virtual Inertia Control of WTGs for Enhancing Primary Frequency Response and Suppressing Drivetrain Torsional Oscillations

IEEE Transactions on Power Systems ◽

10.1109/tpwrs.2021.3055262 ◽

2021 ◽

pp. 1-1

Author(s):

Bi Liu ◽

Qi Huang ◽

Junbo Zhao ◽

Federico Milano ◽

Yingchen Zhang ◽

...

Keyword(s):

Frequency Response ◽

Torsional Oscillations ◽

Virtual Inertia ◽

Inertia Control ◽

Primary Frequency ◽

Primary Frequency Response

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Dual Two-Level Voltage Source Inverter Virtual Inertia Emulation: A Comparative Study

Energies ◽

10.3390/en14041160 ◽

2021 ◽

Vol 14 (4) ◽

pp. 1160

Author(s):

Mohammad Ali Dashtaki ◽

Hamed Nafisi ◽

Amir Khorsandi ◽

Mojgan Hojabri ◽

Edris Pouresmaeil

Keyword(s):

Harmonic Distortion ◽

Synchronous Generator ◽

Voltage Source ◽

Small Signal ◽

Voltage Source Inverter ◽

Nonlinear Loads ◽

Virtual Inertia ◽

The Stability ◽

Stability Enhancement ◽

Oscillation Damping

In this paper, the virtual synchronous generator (VSG) concept is utilized in the controller of the grid-connected dual two-level voltage source inverter (DTL VSI). First, the topology of the VSG and the DTL VSI are presented. Then, the state-space equations of the DTL VSI and the grid-connected two-level voltage source inverter (TL VSI), regarding the presence of the phase-locked loop (PLL) and the VSG, are given. Next, the small-signal modeling of the DTL VSI and the TL VSI is realized. Eventually, the stability enhancement in the DTL VSI compared with the TL VSI is demonstrated. In the TL VSI, large values of virtual inertia could result in oscillations in the power system. However, the ability of the DTL VSI in damping oscillations is deduced. Furthermore, in the presence of nonlinear loads, the potentiality of the DTL VSI in reducing grid current Total Harmonic Distortion (THD) is evaluated. Finally, by using a proper reference current command signal, the abilities of the DTL VSI and the TL VSI in supplying nonlinear loads and providing virtual inertia are assessed simultaneously. The simulation results prove the advantages of the DTL VSI compared with the TL VSI in virtual inertia emulation and oscillation damping, which are realized by small-signal analysis.

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Improvement of transient and small signal stability in micro grid by hybrid technique with virtual synchronous generator control scheme

Transactions of the Institute of Measurement and Control ◽

10.1177/01423312211013173 ◽

2021 ◽

pp. 014233122110131

Author(s):

Santhoshkumar Thenpennaisivem ◽

V. Senthilkumar

Keyword(s):

Synchronous Generator ◽

Emperor Penguin ◽

Hybrid Technique ◽

Small Signal ◽

Small Signal Stability ◽

Change Condition ◽

Hunting Behaviour ◽

Micro Grid ◽

Virtual Inertia ◽

Virtual Synchronous Generator

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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