Ngamroo, Issarachai
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Preferred name
Ngamroo, Issarachai
Alternative Name
Ngamroo, I.
Main Affiliation
Email
issarachai.ng@kmitl.ac.th
5 results
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Item type:Publication, Inertia Assessment From Transient Measurements: Recent Perspective From Japanese WAMS(2022-01-01) ;Kerdphol, Thongchart ;Watanabe, Masayuki ;Mitani, YasunoriCurrently, the substantial renewable penetration brings a low inertia issue to the Japanese power system, threatening stability and resiliency than ever. The inertia estimation based on transient events provides a reliable basis for system control and operation. However, the poor rate of change of frequency extraction from different types and locations of phasor measurement units (PMUs) could significantly lead to inertia estimation errors. As a remedy with a lesson learned, this paper analyzes effective inertia estimations based on transient measurements of the Japanese wide-area monitoring in both distribution and transmission levels. Due to the longitudinally interconnected configuration of the 60 Hz Japanese power system, the polynomial approximation technique is proposed to restrain the strong effect of oscillatory components. To enhance the estimation performance considering an existing center of inertia, the comprehensive mode-shape analysis is performed via geographical measurement locations, indicating sufficient PMUs with precise estimation. The effectiveness of inertia estimation techniques is verified through actual system events corresponding to various transient sites. The numerical results demonstrate that recent inertia of the 60 Hz Japanese system with existing renewables ranges around 7.12 - 8.13 s in its system load base. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Enhanced robust frequency stabilization of a microgrid against simultaneous cyber-attacks(2024-03-01) ;Kerdphol, Thongchart; A microgrid (MG) is a smart grid cyber-physical system, with component coordination relying on cyber resilience. Weak communications, protocols, and tools make the MG's secondary frequency control vulnerable to various cyber-attacks, posing new challenges and stability risks. In response to this challenge, this paper introduces the enhanced robust H<inf>∞</inf> technique considering the dynamic impacts of cyber-attacks on secondary frequency control to develop a secondary frequency control loop, improving the regulation performance and cyber resiliency of the MG frequency. The secondary control cyber-attack strategies mainly rely on false data injection (FDI), denial of service (DoS), and controller hijacking. These attack techniques are simultaneously considered in formulating the H∞ problem and control synthesis as unstructured parametric uncertainty, attenuating the concurrent cyber impacts. The study extends a load frequency control model to illustrate how cyber-attacks can be represented mathematically and physically in the MG. The results reveal that cyber-attacks affect secondary frequency control elements differently depending on the type of cyber threats used. By implementing an enhanced H∞ controller, the MG can effectively maintain stable frequency levels even when faced with malicious attacks and disruptions caused by renewable energy sources and loads. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Synthetic Inertia-Power Sharing in High Renewable Power Grids Through Vehicle-to-Grid Topology(2024-01-01) ;Kerdphol, Thongchart; With the increasing integration of renewable energy sources (RESs), the overall inertia of the power system is expected to decline. The remaining inertia is crucial for regulating system frequency and mitigating excessive rates of change. The deployment of dispatchable loads, such as electric vehicles (EVs), offers a promising solution. This paper presents a synchronized inertia support framework utilizing a vehicle-to-grid (V2G) system through its bidirectional chargers. This concept is realized by integrating a large-scale energy storage system (ESS) composed of controllable EVs into an enhanced inertia emulation structure. The synthetic inertia control strategy has been refined to account for EV user convenience and synchronized state of charge (SOC) management, facilitating synchronized inertia power sharing. This approach enhances the grid's dynamic performance and resilience. Simulation results demonstrate that the proposed method effectively delivers rapid inertia support from the onboard ESS of EVs, improving frequency stability. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Small-signal analysis of multiple virtual synchronous machines to enhance frequency stability of grid-connected high renewables(2021-04-01) ;Kerdphol, Thongchart ;Rahman, Fathin Saifur ;Watanabe, Masayuki ;Mitani, YasunoriHongesombut, KomsanThe virtual synchronous machine technology is considered as an important technique to effectively control the shortcomings of renewable energy-based power electronics interfaces, providing backup inertia and regulating grid stability. Conventionally, the virtual synchronous machine with a large capacity is responsible for controlling the entire grid stability against renewable penetration. It is usually operated as a centralised control system. But what if virtual synchronous machines with small capacities are independently operated by their additional droop control schemes, and will they present better performance than the single virtual synchronous machine? This study proposes the multiple virtual synchronous machine system with different active power-frequency (P-f) droop characteristics to improve inertia support regarding frequency stability improvement. The comprehensive small-signal modelling of the multiple virtual synchronous machine unit is designed to include the additional P-f droop characteristics. Then, the dynamic characteristics (steady-state and transient responses) and static stability of the multiple virtual synchronous machines are compared with the single virtual synchronous machine at the same rated capacity in both eigenvalue/sensitivity-domain and time-domain analysis. The obtained results reveal that the system with the presence of several virtual synchronous machines is more stable than the system with single virtual synchronous machine, maintaining stable and secure system operation during the contingency. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Forced oscillation suppression using extended virtual synchronous generator in a low-Inertia microgrid(2023-09-01) ;Kerdphol, Thongchart; Effects of forced oscillations (FOs) in well-damped power systems are relatively smaller than those of microgrids (MGs) in which the severity of the FOs may be intensified by converter interfaced generators (CIGs). According to the distinct system characteristics, the FOs in MGs will be challenging problems in future research topics. Without proper controls of the CIGs, the FOs may be exhibited extremely higher amplitude, resulting in the MG instability. Such influences will be exacerbated in a low-inertia MG, which can trigger critical frequency oscillation and system collapse. This paper introduces an extended virtual synchronous generator (VSG) with virtual forced components to attenuate the dynamic FO effects in the presence of a low-inertia MG. Contrastive scenarios, i.e., periodic, combined, full sine, and high-frequency FOs are conducted to validate the performances of VSG control in both stand-alone and interconnected MG environments. Numerical results verify that the extended VSG control provides promising benefits in a low-inertia MG not only for the sake of MG stability improvement but also the further FO suppression.
