| 1. |
- Chen, Chunyu, et al.
(författare)
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Equilibrium of Frequency Control Ancillary Service Market Based on Attack-defense Game
- 2024
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Ingår i: Dianwang Jishu/Power System Technology. - : Power System Technology Press. - 1000-3673. ; 48:2, s. 679-687
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Tidskriftsartikel (refereegranskat)abstract
- With the improvement of electricity market rules, the power system operator permits new energy resources to gradually participate in the frequency control ancillary service market. The participation of new energy resources greatly enhance the frequency regulation performance and mutual support of different energy resources. However, some frequency regulation resources are usually equipped with insufficient cyber security protection measures due to economic considerations. Under this situation, hackers may exploit the vulnerability of susceptible cyber physical systems to disrupt the operation of frequency control ancillary service market. Therefore, we analyze frequency modulation market game equilibrium considering the attack-defense game. First, we analyze the cyber attack behaviors aiming at manipulating the bidding information of susceptible resources. Second, we analyze the attack model aiming at maximizing the profit of the complicity. Next, a frequency modulation market equilibrium model considering the master-slave Stackelberg game of both sides of attack and defense is designed. Finally, the frequency modulation market equilibrium results based on the Column-and-Constraint Generation (C&CG) algorithm are analyzed. Through case analysis of 30-unit frequency regulation markets, the average deviation of capacity revenue change from 113.89% under attack to 12.56% after defense, indicating that the defender can to a certain extent suppress the market equilibrium deviation caused by the attacker.
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| 2. |
- Cheng, Qiaoyun, et al.
(författare)
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The conversion of nanocellulose into solvent-free nanoscale liquid crystals by attaching long side-arms for multi-responsive optical materials
- 2020
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Ingår i: Journal of Materials Chemistry C. - : ROYAL SOC CHEMISTRY. - 2050-7526 .- 2050-7534. ; 8:32, s. 11022-11031
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Tidskriftsartikel (refereegranskat)abstract
- Nanocellulose, with its unique optical and chemical properties, has received increasing attention as feedstock to fabricate sustainable materials. However, achieving a nanocellulose-based solvent-free liquid crystal with good responsiveness still remains a challenge. Herein, for the first time, solvent-free supramolecular liquid crystals were fabricated by attaching long side-arms on the fiber-like nanocellulose derived from tunicate (TCNC) with an average width of 20 nm and 400-3000 nm in length. The side-arms were grafted via surface condensation with a charged organosilane, followed by further functionalization with a counter-ion polyoxyethylene ether. The nanoscale liquid crystals consisted of the stiff TCNC as the core and flexible side-arms as the soft shells, forming the core-shell structure with an average width of 34-36 nm. The resulting solvent-free liquid crystal exhibited transparent and viscous liquid-like fluidity, as well as a bright birefringence between the crossed polarizers at room temperature. In our findings, the stiff core provided crystal-like ordering, whereas the soft shells induced the high mobility of the TCNCs as a result of the increased fractional free volume, as shown by positron annihilation lifetime spectra. The unique flowability enables the possibility of multi-responsiveness to temperature, deformation, and alternating electric fields. In addition, the thermo-responsiveness can be regulated by tailoring the canopy. This work provides a novel strategy for the conversion of solid nanocellulose into a solvent-free nanoscale liquid crystal, which is promising for use as a responsive optical material.
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| 3. |
- Wang, Ying, et al.
(författare)
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A tri-level programming-based frequency regulation market equilibrium under cyber attacks
- 2023
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Ingår i: Protection and Control of Modern Power Systems. - : Springer Nature. - 2367-2617 .- 2367-0983. ; 8:1
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Tidskriftsartikel (refereegranskat)abstract
- Owing to their flexibility and rapid response, grid-connected distributed energy resources (DERs) are wielding growing influence in frequency regulation markets (FRMs). Nevertheless, compared with conventional large-scale generators, small-scale DERs are usually weakly shielded by cyber security measures. This offers attackers the opportunity of disrupting the clearing and settlement of FRMs by manipulating the bid information of DERs. In this paper, the frequency regulation market equilibrium is studied considering the dynamic gaming between attackers and defenders, both of which need the knowledge of FRMs for their interventions. Specifically, a tri-level programming model characterizing the attacker–defender–operator (ADO) interdiction problem in FRMs is developed and then analyzed using a column and constraint generation algorithm, thereby achieving market equilibrium representing the defender's best response to the attacker. The defense strategy in the market equilibrium can attenuate the negative influence of cyber attacks upon the FRMs to the maximum extent. Finally, based on the operating rules of the California Independent System Operator, the FRM process considering the ADO interdiction is simulated and the numerical equilibrium results are presented.
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