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As natural disasters and abnormal weather phenomena continue to cause damage to power systems, resilience has become a critical characteristic for future power grids. While microgrids (MGs) have been studied as a potential source of resilience, previous research has mainly focused on operational strategies to improve the resilience of existing MGs. This study proposes a planning approach for a gas-electric-based integrated multi-energy system that includes a microgrid to enhance the power grid's resilience against serious failures. The approach includes an operational process to achieve a specific resiliency level at the lower level, and a bi-level optimization method that considers cost effects at the upper level. The proposed method uses mixed-integer linear programming (MILP) to establish the operational process based on the required resilience level and determine the optimal location for each asset in the microgrid. The effectiveness of the proposed method is evaluated using the IEEE 33 Bus test system in various severe failure scenarios. The results demonstrate that the proposed planning approach can effectively enhance the resilience of power grids through the integration of microgrids, and the bi-level optimization method can provide an optimal solution while considering the cost-effectiveness of the microgrid.

This paper summarizes the report prepared by an IEEE PES Task Force. Resilience is a fairly new technical concept for power systems, and it is important to precisely delineate this concept for actual applications. As a critical infrastructure, power systems have to be prepared to survive rare but extreme incidents (natural catastrophes, extreme weather events, physical/cyber-attacks, equipment failure cascades, etc.) to guarantee power supply to the electricity-dependent economy and society. Thus, resilience needs to be integrated into planning and operational assessment to design and operate adequately resilient power systems. Quantification of resilience as a key performance indicator is important, together with costs and reliability. Quantification can analyze existing power systems and identify resilience improvements in future power systems. Given that a 100% resilient system is not economic (or even technically achievable), the degree of resilience should be transparent and comprehensible. Several gaps are identified to indicate further needs for research and development.

Dr. Le Xie is a Professor, Chancellor EDGES Fellow, and Presidential Impact Fellow in the Department of Electrical and Computer Engineering at Texas A&M, and the Assistant Director-Energy Digitization at Texas A&M Energy Institute. He was awarded the 2017 IEEE PES Outstanding Young Engineer Award for the best power engineer under 35. He is the founding chair of IEEE PES Subcommittee on Big Data & Analytics for Grid Operations.

Resource additions to electric power grids are planned in advance to maintain reliability of electric power supply. This is achieved by performing reliability studies for calculating reliability indices at the planning stage to ensure that the required levels of reliability will be met. This article proposes a new state classification approach to calculate power system reliability indices using a combination of multilabel radial basis function (MLRBF) networks and importance sampling (IS) within the framework of Monte Carlo simulation process. Multilabel classification algorithms are different from single-label approaches, in which each instance can be assigned to multiple classes. This characteristic gives MLRBF the capability to classify composite power system states (success or failure), at the bus as well as system level. Bus level indices provide useful reliability information for locational reliability, which allows more rational and equitable distribution of resources. MLRBF classification does not require optimal power flow (OPF) analysis; however, OPF is required for the training and cross-entropy optimization phases. This article shows that the scope and computational efficiency to evaluate reliability indices can be significantly increased if the proposed MLRBF classifier is used together with well-known variance reduction technique of IS. As the classifier is trained to recognize the reliability status of a system state, it can also be used in operational planning when a number of scenarios need to be evaluated in a short time for their ability to satisfy load. The proposed method is illustrated using the IEEE reliability test system for different load levels. The outcomes of case studies show that MLRBF algorithm together with IS provides excellent classification accuracy in reliability evaluation while substantially reducing computation time and enhancing the scope of evaluation.

•An open access tool to model cryptocurrency mining’s impact on the electric grid.•The per-unit carbon footprint of cryptomining has high locational disparity.•Mining loads’ flexibility significantly reduces their reliability concerns.•Mining loads participation in demand response mitigates market disruptions.

Deregulation of electric power industries in recent years has opened many opportunities for electricity buyers. However, the strong influence of network physical constraints may result in economic decisions that adversely affect the interests of the consumers. Compared with the monopolistic economy of yesteryears, electricity buyers may actually be able to influence the market by cooperating with other buyers in the network. This paper presents a coevolutionary approach to investigate individual and cooperative strategies of buyers in a power market, taking fully into account the physical network constraints. First, the study focuses on deterministic cases, where buyers choose their bidding strategies to maximize the profits in different scenarios of playing individually or cooperatively. It is found that, by evolutionary learning, buyers can benefit from cooperation. After that, the uncertain nature of the market is modeled, where buyers find optimal cooperation strategies to hedge against the risk of low payoffs. The payoff distribution problem in cooperative game theory was linked with the optimal coalition generation problem by proving a theorem. The statistically consistent simulation results show that our approach is able to discover interesting cooperation strategies and can be easily extended to practical networks with a large number of buyers.

•An extendable grid model with a power outage dataset is released.•Single demand flexibility mechanisms show decaying marginal effect.•Demand flexibility mechanisms show non-linear dependency when combined.•Combined demand flexibility mechanisms are identified to avoid blackout.

•An open-source Texas power grid model with real blackout data is available.•Model-based simulation captures key characteristics of the 2021 Texas blackout.•The sensitivity of corrective measures on event severity mitigation is quantified.•Per-GW generator winterization has distinct performance.

Contingency ranking and selection is an indispensable tool for static security analysis. Several performance indices suffer either from misranking or computational inefficiencies. This paper presents a new performance index for MW line flow contingency selection and ranking. The proposed index is derived from real power transmission losses. It is a quadratic function of bus voltage angles and can easily be calculated from real power flows or DC load flow. It improves both the selectivity and the ranking of second order performance index without excessive computational effort. The proposed method is tested on IEEE 24-bus reliability test system and IEEE 30-bus test system. The results are compared with those of the conventional second order performance index and of the tenth order reference performance index from the point of ranking and selectivity.Contingency ranking and selection is an indispensable tool for static security analysis. Several performance indices suffer either from misranking or computational inefficiencies. This paper presents a new performance index for MW line flow contingency selection and ranking. The proposed index is derived from real power transmission losses. It is a quadratic function of bus voltage angles and can easily be calculated from real power flows or DC load flow. It improves both the selectivity and the ranking of second order performance index without excessive computational effort. The proposed method is tested on IEEE 24-bus reliability test system and IEEE 30-bus test system. The results are compared with those of the conventional second order performance index and of the tenth order reference performance index from the point of ranking and selectivity.

The immobilized glutamate dehydrogenase of Aspergillus ochraceuson alkylamine glass exhibited 39% of the initial enzyme activity and a conjugation yield of 13.6 mg enzyme protein/g support. The Km of the bound enzyme varied while Vmax remained unaltered. The immobilized enzyme was optimally active at pH 8.6 with greater potential for prolonged and repeated use.

Abstract: Chronic administration of ethanol in rats caused the reduction of serum cholesterol binding reserve. The very low density and high density lipoproteins, main serum cholesterol binding reserves, were slightly increased with corresponding increases in their lipid and protein components during initial stage of alcohol consumption. However, these capacities get deminished during reversal of hyperlipemia induced by prolonged action of ethanol. This situation may be an early indicator for the initiation of hepatic damage and a variety of secondary effects of ethanol.

The levels of lipid peroxides in circulatory lipoproteins increased with chronic administration of ethanol or acetaldehyde. Low density lipoprotein showed a greater increase in its content of lipid peroxides than very low density lipoprotein or high density lipoprotein. However, very low density lipoprotein was more prone to lipid peroxidationin vitrothan low density lipoprotein or high density lipoprotein. The effect of acetaldehyde was more marked than that of ethanol. Lipoproteins of control and hyperlipemic groups were partially protected against peroxidation by butyrated hydroxytoluene and serum high density lipoprotein of normal rats.

Abstract: The levels of lipoprotein-X in circulation increased with chronic administration of ethanol or acetaldehyde. A similar profile was seen in rat serum with alkaline phosphatase activity and bilirubin content. Total cholesterol, phospholipids and triglyceride contents increased followed by a decrease by progressive feeding with ethanol or acetaldehyde. The effect of acetaldehyde was more pronounced than that of ethanol.

Abstract: The interactions of flavin mononucleotide (riboflavin-5'-monophosphate) with two polypeptides, poly-(α-L-lysine) and poly-(α-L-histidine) in water and 0.05 M phosphate buffer were studied by measuring circular dichroism in the pH range 3 to 11. The interation of flavin mononucleotide with the two polypeptides was due to hydrophobic as well as ionic associations and was further influenced by the involvement of the ribityl side chain. The results of the present study have shown that small changes in the environmental conditions of the interacting molecules could modify their mode of interaction considerably.

This paper presents a methodology for the reliability analysis of standby and emergency power systems. The techniques are illustrated using an example of standby generators and an uninterruptible power supply system.<>

Summary A new class of cationic metal complexes (chromotropes) of cobalt, chromium and copper has been found to induce true metachromasia in methyl blue (anionic dye). These novel species produced a stronger metachromatic reaction than do known chromotropes. The spectral shifts and meta-chromatic effects were found to increase with increasing chromotropes to dye (methyl blue)ratios. The metachromatic reactions were suppressed by versene, urea, propanol

The multicomponent character of all commercial anionic dyes tested (monoazo, disazo, indigoid and xanthene) was demonstrated by paper chromatography. On the basis of a reaction on filter paper, certain fractionated components of the dyes: aniline blue WS, benzoazurin, Bordeaux red, Congo red, cotton blue, chromotrope 2R, indigo-carmine, methyl-blau, soluble blue, and wasserblau showed a metachromatic response with the chromotropes, protamine and hexammine cobaltic chloride. The response of these same dye components with the chromotropes neomycin, polymyxin and viomycin was much weaker, and the alkaloids strychnine, codeine and cinchonidine could not elicit any metachromatic response. The hex-amminocobalt complex was the most effective of all the chromotropes studied, including protamine, both on filter paper and in aqueous solutions. Changes in color exhibited by the unchromatographed whole dyes such as alkali blue, alkali blue 6B, azoblau, Congo rubin, Hickson purple, isamine blue, orange G and trypan blue appear to be merely polychromatic effects because comparable changes are not shown by any of their chromatographically resolved components. In a solution system, the blue dyes, benzoazurin, cotton blue, indigo-carmine, methylblau, soluble blue, and wasserblau did not show definite visual changes in hue or in spectral shifts except with the hexamminocobalt complex, which induced a remarkable change in hue of all these dyes to a blue-violet or purple shade. A spectrophotometric study of methylblau has indicated that this change in hue is associated with a 25 mp shift of absorbance maximum to a lower wave length (hypsochromic effect). The filter-paper reaction between a dye component and a chromotrope is quite reliable and convenient for ascertaining a metachromatic response, since, unlike a reaction in solution systems, it is not affected by the unbound components of a reaction mixture. It is usable because water does not play any significant role in the metachromasy of anionic dyes. No correlation has been established between metachromasy and chemical constitution of anionic dyes.

Desferal, N-acetyl penicillamine (metal chelators) and propylgallate, catechin, and reduced glutathione (antioxidants) suppressed the erythrocytic oxidative damage generated during Plasmodium berghei infection in Mastomys coucha. Superoxide anion and lipid peroxide levels were increased and on the contrary, superoxide dismutase activity was noticeably decreased in the infected erythrocytes. Metal chelators/antioxidant treatment to infected animals resulted in restoration of O2−, LPO and SOD to near normal levels. Furthermore, treatment of the above mentioned agents displayed a controlled mortality/survival time and parasitaemia. In conclusion, metal chelators/antioxidants were found to be effective against oxidative stress injury and parasite growth resulting in prolonged survival time of the host during experimental malaria.