Forced oscillation in power systems with converter controlled-based resources- a survey with case studies

In future power systems, conventional synchronous generators will be replaced by converter controlled-based generations (CCGs), i.e., wind and solar generations, and battery energy storage systems. Thus, the paradigm shift in power systems will lead to the inferior system strength and inertia scarcity. Therefore, the problems of forced oscillation (FO) will emerge with new features of the CCGs. The state-of-the-art review in this paper emphasizes previous strategies for FO detection, source identification, and mitigation. Moreover, the effect of FO is investigated in a power system with CCGs. In its conclusion, this paper also highlights important findings and provides suggestions for subsequent research in this important topic of future power systems. © 2013 IEEE

Forced oscillation detection amid communication uncertainties

This article proposes a novel technique for the detection of forced oscillation (FO) in a power system with the uncertainty in the measured signals. The impacts of communication uncertainties on measured signals are theoretically investigated based on the mathematical models developed in this article. A data recovery method is proposed and applied to reconstruct the signal under the effects of communication losses. The proposed FO detection with communication uncertainties is evaluated in the modified 14-machine Southeast Australian power system. A rigorous comparative analysis is made to validate the effectiveness of the proposed data recovery and FO detection methods

Performance of wide-area power system stabilizers during major system upsets: investigation and proposal of solutions

© 2021 Springer Nature Switzerland AG. This is a post-peer-review, pre-copyedit version of Benasla, M., Denaï, M., Liang, J. et al. Performance of wide-area power system stabilizers during major system upsets: investigation and proposal of solutions. Electr Eng (2021). The final authenticated version is available online https://doi.org/10.1007/s00202-020-01168-3Wide-area damping controllers (WADCs) are effective means of improving the damping of inter-area oscillations and thereby ensuring a secure operation of modern highly stressed interconnected power systems; however, their implementation costs are high. Therefore, the controller must be well configured and designed to ensure its cost-effectiveness. Several techniques have been proposed in the literature to design effective controllers and good results have been achieved. However, some important practical aspects that could potentially impact the performance of the designed controller have not been addressed or studied in sufficient detail in these previous works. One such aspect is assessing the performance of the designed controllers under major system upsets resulting in large deviations in the frequency and fluctuations in the power. These may lead to controller saturation which could negatively impact its damping performance or even cause instability. In this paper, the impact of such large upsets is investigated on several test systems via extensive small- and large-signal analyses and it is shown that, during severe transients, controller saturation may occur and persist over a long period of time, posing a potential threat to the power system stability. This paper presents a very effective solution to alleviate this problem and help design more robust WADCs. The simulation results show that the proposed solution works well and leads to improved power system stabilisers performance during transient upsets.Peer reviewedFinal Accepted Versio

Anti-Acanthamoeba activity of a semi-synthetic mangostin derivative and its ability in removal of Acanthamoeba triangularis WU19001 on contact lens

Garcinia mangostana L., also known as the mangosteen tree, is a native medicinal plant in Southeast Asia having a wide variety of pharmacologically active compounds, including xanthonoid mangostin. In this study, we examined the pharmacological activities of the selected semi-synthetic mangostin derivative, namely, amoebicidal activity, encystation inhibition, excystation activity, and removal capacity of adhesive Acanthamoeba from the surface of contact lens (CL). Among the three derivatives, C1 exhibited promising anti-Acanthamoeba activity against Acanthamoeba triangularis WU19001 trophozoites and cysts. SEM images displayed morphological changes in Acanthamoeba trophozoites, including the loss of acanthopodia, pore formation in the cell membrane, and membrane damage. In addition, the treated cyst was shrunken and adopted an irregular flat cyst shape. Under a fluorescence microscope, acridine orange and propidium iodide (AO/PI) staining revealed C1 induced condensation of cytoplasm and chromatin with the loss of cell volume in the treated trophozoites, while calcofluor white staining demonstrated the leakage of cell wall in treated cysts, leading to cell death. Interestingly, at the concentration ranges in which C1 showed the anti-Acanthamoeba effects (IC50 values ranging from 0.035–0.056 mg/mL), they were not toxic to Vero cells. C1 displayed the highest inhibitory effect on A. triangularis encystation at 1/16×MIC value (0.004 mg/mL). While C1 demonstrated the excystation activity at 1/128×MIC value with a high rate of 89.47%. Furthermore, C1 exhibited the removal capacity of adhesive Acanthamoeba from the surface of CL comparable with commercial multipurpose solutions (MPSs). Based on the results obtained, C1 may be a promising lead agent to develop a therapeutic for the treatment of Acanthamoeba infections and disinfectant solutions for CL

Targeting Acanthamoeba proteins interaction with flavonoids of Propolis extract by in vitro and in silico studies for promising therapeutic effects

Background: Propolis is a natural resinous mixture produced by bees. It provides beneficial effects on human health in the treatment/management of many diseases. The present study was performed to demonstrate the anti-Acanthamoeba activity of ethanolic extracts of Propolis samples from Iran. The interactions of the compounds and essential proteins of Acanthamoeba were also visualized through docking simulation. Methods: The minimal inhibitory concentrations (MICs) of Propolis extract against Acanthamoeba trophozoites and cysts was determined in vitro. In addition, two-fold dilutions of each of agents were tested for encystment, excystment and adhesion inhibitions. Three major compounds of Propolis extract such as chrysin, tectochrysin and pinocembrin have been selected in molecular docking approach to predict the compounds that might be responsible for encystment, excystment and adhesion inhibitions of A. castellanii. Furthermore, to confirm the docking results, molecular dynamics (MD) simulations were also carried out for the most promising two ligand-pocket complexes from docking studies. Results: The minimal inhibitory concentrations (MICs) 62.5 and 125 µg/mL of the most active Propolis extract were assessed in trophozoites stage of Acanthamoeba castellanii ATCC30010 and ATCC50739, respectively. At concentrations lower than their MICs values (1/16 MIC), Propolis extract revealed inhibition of encystation. However, at 1/2 MIC, it showed a potential inhibition of excystation and anti-adhesion. The molecular docking and dynamic simulation revealed the potential capability of Pinocembrin to form hydrogen bonds with A. castellanii Sir2 family protein (AcSir2), an encystation protein of high relevance for this process in Acanthamoeba. Conclusions: The results provided a candidate for the development of therapeutic drugs against Acanthamoeba infection. In vivo experiments and clinical trials are necessary to support this claim

Forced oscillation management in future power grids with high penetration of converter controlled-based resources

Forced oscillation (FO) events were detected in actual power systems, i.e., Nordic and Western America power systems. These events could result in the widespread blackout in the power systems. Accordingly, intensive researches in the FO detection, source identi cation and mit- igation are sought. In future power systems, conventional synchronous generators will be replaced by converter controlled-based generations (CCGs), i.e., wind and solar generations, and battery energy storage systems. Thus, the paradigm shift in power systems will lead to the inferior system strength and inertia scarcity. Therefore, problems of the FO detection, source identi cation and mitigation will emerge with new features of the CCGs. To deal with the aformentioned problems, the following contribu- tions are made in the thesis: i) a novel technique for detection of FO in a power system when the measured signals received through the com- munication channels are uncertain. Impacts of communication uncer- tainties on measured signals are theoretically investigated based on the mathematical models. Communication uncertainties are integrated in the remote signal measurements for monitoring and controlling of the FO. Theoretical investigation of the in uence of communication uncer- tainties such as variable latencies, packet disorders and packet losses on the FO analysis, and detection under several scenarios in a power system, is conducted. The development of data recovery technique to reconstruct the signal a ected by communication uncertainties is pro- posed with the establishment of the technique of continuous detection to improve the performance of the FO analysis and detection under vari- ous operations and communication uncertainties, ii) the new design and development of a controller termed as a forced oscillation damping con- troller (FODC) for damping FO considering uncertainty and periodic disturbances is proposed. An adaptive control algorithm is proposed to adjust the control parameters of FODC under various system oper- ations appropriately, uncertainties, and forced disturbances. Besides, a new control design for simultaneous inter-area and FO damping is pro- posed, iii) A uni ed FODC design method to deal with all oscillation caused by non-stationary FOs is proposed. Mathematical analyzes of the impacts of the non-stationary FO on electromechanical modes and sub/super synchronous modes considering various scenarios are con- ducted. The proposed solution consists of a continuous FO detection and robust-adaptive FO mitigation. A modi ed continuous detection is applied to monitor the non-stationary FO. Major stability indices such as damping, frequency, interaction, and robustness can be calculated without requiring exact system parameters, and v) A forced oscillation management framework incorporating the hierarchical neural network of distributed CCGs is proposed. Analyze and investigate the FO e ects in a low-inertia MG with distributed CCGs are conducted under various MG operating points, uncertainties, and FO conditions. The proposed method is able to properly manage big data produced from DCRs and suggest optimal solutions for FO detection, source identi cation, and mitigation in a low-inertia MG with DCRs. The simulation results show that the proposed methods in this thesis can accurate detect the FO under communication uncertainties. More- over, the proposed detection can di erentiate the FO from the elec- tromechanical oscillations. The proposed damping controller can sup- press both stationary and non-stationary FOs e ectively. Besides, the proposed FO management framework with the hierarchical neural net- work can detect and locate the FO source precisely, and suppress the FO in a low-inertia microgrid with CCGs automatically

Control of distributed converter-based resources in a zero-inertia microgrid using robust deep learning neural network

Considering the evolution of future microgrids (MGs) towards zero-inertia level due to the penetrations of distributed converter-based resources (DCRs), a large number of data produced by these generations will lead the control decisions to be more complicated than conventional power systems. This paper presents a control strategy for a zero-inertia MG with DCRs using a robust deep learning neural network (RDeNN). In a training phase, a sub-space state-based identification method is employed to monitor and analyze the data regarding stability indices, i.e., damping and frequency of dominant modes, and robustness against uncertainties. In addition, a mixed H2/

Coordinated decentralized and centralized microgrid control for distributed renewable energy sources with integrated batteries

Abstract Renewable energy sources (RESs) with integrated batteries (IBESSs) in microgrid (MGs) have well been developed by aggregate models in previous research works. Either decentralized or centralized control is applied as a standard platform to manage the aggregate models. However, these may not be valid assumptions in practical MGs, which consist of various distributed RESs with IBESSs and control platforms. As a result, controllers designed for the aggregate models may be ineffective, when they are applied for distributed models in actual MGs. To deal with these problems, this paper proposes a coordinated decentralized and centralized MG control strategy of distributed RESs and IBESSs (DIBESSs). New modellings of the distributed RESs with DIBESSs are developed here so that appropriate controllers can be designed to manage voltage and frequency of a MG. An adaptive‐robust approach is applied to achieve flexible control performance of the RESs with DIBESSs against MG uncertainties, operating points, and conditions. Comparative analyses of the conventional, aggregate, and distributed models are made. Simulation results in an inertia‐less microgrid with 100% RESs verify the capability of the proposed control strategy for the distributed models

Forced oscillation suppression using extended virtual synchronous generator in a low-Inertia microgrid

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. © 2023 Elsevier Lt