A review of key strategies in realizing power system resilience

The world is witnessing increasing frequency of extreme events. The power system is the backbone critical infrastructure of our economy and is under treat of such events. The resilient power system is intended to cope with low probability, high risk extreme events including extreme natural disasters and man-made attacks. Realizing resilience in the power system has been an unprecedented mission. Equipped with today’s smart grid technologies, power system can be rendered more resilient by the strategies taken before, during and after a disruptive event erupts. Based on a thorough review of existing works, we present the most-investigated problems and solving measures according to their application stage. In the preparation stage, innovative planning frameworks considering disaster scenarios are discussed; after the event, the system can alter the topology and integrate resource allocation to alleviate load shedding. The characteristics of different disasters are investigated to facilitate enhancing resilience. The review provides a summary of resilience strategies in the power system and can shed light to future research and application.

Two antibodies show broad,synergistic neutralization against SARS-CoV-2 variants by inducing conformational change within the RBD

Continual evolution of the severe acute respiratory syndrome coronavirus(SARS-CoV-2)virus has allowed for its gradual evasion of neutralizing antibodies(nAbs)produced in response to natural infection or vaccination.The rapid nature of these changes has incited a need for the development of superior broad nAbs(bnAbs)and/or the rational design of an antibody cocktail that can protect against the mutated virus strain.Here,we report two angiotensin-converting enzyme 2 competing nAbs—8H12 and 3E2—with synergistic neutralization but evaded by some Omicron subvariants.Cryo-electron microscopy reveals the two nAbs synergistic neutralizing virus through a rigorous pairing permitted by rearrangement of the 472-489 loop in the receptor-binding domain to avoid steric clashing.Bispecific antibodies based on these two nAbs tremendously extend the neutralizing breadth and restore neutralization against recent variants including currently dominant XBB.1.5.Together,these findings expand our understanding of the potential strategies for the neutralization of SARS-CoV-2 variants toward the design of broad-acting antibody therapeutics and vaccines.

Component importance assessment of power systems for improving resilience under wind storms

Increasingly natural disasters and man-made malicious attacks threaten the power systems.Improving the resilience has become an inevitable requirement for the development of power systems.The importance assessment of components is of significance for resilience improvement,since it plays a crucial role in strengthening grid structure,designing restoration strategy,and improving resource allocation efficiency for disaster prevention and mitigation.This paper proposes a component importance assessment approach of power systems for improving resilience under wind storms.Firstly,the component failure rate model under wind storms is established.According to the model,system states under wind storms can be sampled by the non-sequential Monte Carlo simulation method.For each system state,an optimal restoration model is then figured out by solving a component repair sequence optimization model considering crew dispatching.The distribution functions of component repair moment can be obtained after a sufficient system state sampling.And Copeland ranking method is adopted to rank the component importance.Finally,the feasibility of the proposed approach is validated by extensive case studies.

Voltage Stability Constrained Optimal Power Flow for Unbalanced Distribution System Based on Semidefinite Programming

This paper proposes a voltage stability constrained optimal power flow(VSC-OPF)for an unbalanced distribution system with distributed generators(DGs)based on semidefinite programming(SDP).The AC optimal power flow(ACOPF)for unbalanced distribution systems is formulated as a chordal relaxation-based SDP model.The minimal singular value(MSV)of the power flow Jacobian matrix is adopted to indicate the voltage stability margin.The Jacobian matrix can be explicitly expressed by ACOPF state variables.The nonlinear constraint on the Jacobian MSV is then replaced with its maximal convex subset using linear matrix inequality(LMI),which can be incorporated in the SDP-based ACOPF formulation.A penalty technique is leveraged to improve the exactness of the SDP relaxation.Case studies performed on several IEEE test systems validate the effectiveness of the proposed method.