Contingency States Research Articles

Interpreting the value of flexibility in AC security-constrained transmission expansion planning via a cooperative game framework

Security-constrained transmission expansion planning (SCTEP) is an inherently complex problem that requires simultaneously solving multiple contingency states of the system (usually corresponding to N-1 security criterion). Existing studies focus on effectively finding optimal solutions; however, single optimal solutions are not sufficient to interpret the value of flexibility (e.g., from energy storage systems) and support system planners in well-informed decision making. In view of planning uncertainties, it is necessary to estimate the contributions of flexibility to various objectives and prioritise the most effective investments. In this regard, this work introduces a SCTEP tool that enables interpreting the value of flexibility in terms of contributions to avoided load curtailment and total expected system cost reduction. Inspired by cooperative game theory, the tool ranks the contributions of flexibility providers and compares them against traditional line reinforcements. This information can be used by system planners to prioritise investments with higher contributions and synergistic capabilities.

Optimal Scheduling of Integrated Energy System Considering Electric Vehicle Battery Swapping Station and Multiple Uncertainties

In recent years, there has been rapid advancement in new energy technologies aimed at mitigating greenhouse gas emissions stemming from fossil fuels. Nonetheless, uncertainties persist in both the power output of new energy sources and load. To effectively harness the economic and operational potential of an Integrated Energy System (IES), this paper introduces an enhanced uncertainty set. This set incorporates N-1 contingency considerations and the nuances of source–load distribution. This framework is applied to a robust optimization model for an Electric Vehicle Integrated Energy System (EV-IES), which includes Electric Vehicle Battery Swapping Station (EVBSS). Firstly, this paper establishes an IES model of the EVBSS, and then proceeds to classifies and schedules the large-scale battery groups within these stations. Secondly, this paper proposes an enhanced uncertainty set to account for the operational status of multiple units in the system. It also considers the output characteristics of both new energy sources and loads. Additionally, it takes into consideration the N-1 contingency state and multi-interval distribution characteristics. Subsequently, a multi-time-scale optimal scheduling model is established with the objective of minimizing the total cost of the IES. The day-ahead robust optimization fully considers the multivariate uncertainty of the IES. The solution employs the Nested Column and Constraint Generation (C&CG) algorithm, based on the distribution characteristics of multiple discrete variables in the model. The intraday optimal scheduling reallocates the power of each unit based on the robust optimization results from the day-ahead scheduling. Finally, the simulation results demonstrate that the proposed method effectively reduces the conservatism of the uncertainty set, ensuring economic and stable operation of the EV-IES while meeting the demands of electric vehicle users.

La contingenza della norma: il monstrum.


 
 
 What does it really mean to contemplate the “anomalous”, the “malformed”, the “anatomical- monster”? Why and how is it so disturbing? And what is the proper norm and status of the monster? The monster is what shocks, the weird, the eerie. The monster is the uncanny, the “unhomely”, das Unheimliche, to borrow from Freud’s famous expression. It’s the irruption of the improper that threatens the stability of life, as it indicates how the commonness of life itself is a precarious yet contingent state. The monster upsets us because it shows us the contingency of the norm. Based upon this assumption, we shall also touch upon other concepts. These might be: the transvaluation of values, the Einverleibung, the Great Health and the theory of the hopeful monster. It is, in the end, a new form of the same: the individual subtracts itself, therefore, from the individuality of the species, but it does so as to affirm a different same that is absolutely contingent. To borrow again from Deleuze, we might say: a “prodigious”, unexpected turn of the becoming.
 
 

PV and QV analysis for finding the optimum location of FACTS device to investigate the effectiveness in KR power system using PSS/E

This paper presents the effect of Static Synchronous Compensator (STATCOM) device in power system for power flow and voltage stability analysis. The stability of power system is most important evaluation that is needed to be considered under various contingency states. This paper presented Power-Voltage (PV) and Reactive power-Voltage (QV) analysis which have been widely used in steady state of power system in normal operating condition and gives important details about the loading of the system and voltage stability. The shunt and series compensation can be used to increase the voltage and flow in the power system. Kurdistan Region Power System (KRPS) used to verify the effectiveness and performance of STATCOM in power system. PSS/E proposed as power system software for KRPS. The result shows that the proposed Full Newton Raphson (FNR) method spends less execution time and the optimum placement for STATCOM for enhancing static voltage stability margin and improves the power transmission capability of the line is the 'weakest bus' of the system.

Mixed Integer Linear Programming Applied to Adaptive Directional Overcurrent Protection Considering N-1 Contingency

This work proposes a methodology for directional overcurrent protection coordination in interconnected transmission systems considering a possible network contingency state. The methodology uses the short-circuit data of the current network topology; however, the maximum load current data in the protection section of each relay is obtained considering the n-1 criterion, already foreseeing the disconnection of some network line. Thus, if a line gets disconnected, other protective devices will not improperly actuate by the redistribution of load currents in the network. The objective is to propose an adaptive protection scheme to redo the coordination for each topological change in the network. To this end, this work considers a smart grid environment with a supervisory system with communication capability between this and the remote devices. To obtain the optimal performance, the coordination problem, originally non-linear and non-convex, is linearized, allowing its formulation as a Mixed Integer Linear Programming problem. The methodology is applied to the 8-bus test system in 3 different cases and the 30-bus test system. Results show that the optimal coordination is obtained in a fast computational processing time, showing the suitability of the methodology for real-time application.

Stochastic Security-Constrained Economic Dispatch of Load-Following and Contingency Reserves Ancillary Service Using a Grid-Connected Microgrid during Uncertainty

In the context of the growing penetration of renewable power sources in power systems causing probabilistic contingency conditions, a suitable economic dispatch model is decisively needed. There is a lack of research in the field of probabilistic mathematical formulation considering the uncertainties due to the stochastic nature of renewables and contingency occurrence, as it is a very complex problem to be solved. The most appropriate model is the stochastic security-constrained economic dispatch (SSCED) model for optimized economic dispatch decisions during uncertainty. However, because of its complexity, it is rarely employed. This paper attempts to solve the complex SSCED problem in the presence of the uncertainty of resources and probabilistic contingency conditions, which is a novel effort in this regard. The SSCED is carried out over multiple periods to provide the load-following or contingency reserves. In the proposed SSCED, the uncertainty problem is addressed by modeling the stochastic wind energy power source by using “probability transition scenarios”. The uncertainty caused by probabilistic contingency conditions in the dispatch schedule is approximated using a “state-specific transition matrix”. The frequency control reserves in contingency conditions are co-optimized with energy, and stochastic security-constrained economic dispatch is achieved. The efforts are put forward to suggest a new market model in the presence of the uncertainty of renewable energy availability. Case studies are examined to show the potential technical and financial advantages of the proposed SSCED through co-optimization. Grid-connected microgrid owners offer frequency control ancillary services by providing load-following ramping reserves in the normal state and contingency reserves in the state of contingency. The probabilistic contingencies considered are generator failure and an underloading condition. A modified “IEEE 30 bus system” is considered a grid-connected microgrid for testing the proposed SSCED. The results show that the greater the flexibility of the resources, the greater the technical and economic benefits. The increase in ramping flexibility of a wind source results in almost an 8.1% reduction in operational costs compared to the base case. The contingency condition analysis shows that the presence of ramping reserves in the system enhances the power system performance, avoiding the cascading effects that ultimately cause a power system failure.

Enduring Contingency

Van der Walt, in my reading, suggests that enduring contingency, in the twofold sense of an enduring state of contingency and of contingency as what needs to be endured, justifies the central role of the majority/minority principle in liberal democratic law. Does this endorsement of the principle go far enough in addressing the radical challenge of contingency? What about those cases in which a group refuses to understand itself as a disaffected minority in conflict with a majority, hence as part of a unity, even if only the unity of a legal order? At issue is a group that demands exclusion from a polity rather than demanding its recognition and inclusion as a minority entitled to be treated as equal to, even if different from, the majority. I suggest that, in the end, Van der Walt justification of the majority/minority principle espouses an agonistic defence of political and legal unity.

A Branch-independence-based Reliability Assessment Approach for Transmission Systems

This paper proposes a branch-independence-based reliability assessment approach for transmission systems. The approach consists of branch decoupling and state-space partition techniques. By integrating an impact-increment-based reliability index calculation model and the proposed branch decoupling technique, a proportion of sampled contingency states no longer need to be analyzed using the time-consuming optimal power flow (OPF) algorithm. In this way, the technique speeds up the calculation of reliability indices. Since first-order contingency states have a high probability of being sampled, we propose a state-space partition technique to replace first-order contingency state simulation with first-order contingency state enumeration. Consequently, the calculation of reliability indices is further accelerated by avoiding a large amount of repetitive OPF analyses during simulation process without affecting reliability index accuracy. The validity and applicability of our approach are verified using the IEEE 118-bus and IEEE 145-bus systems. Numerical results indicate that the proposed approach can improve computational efficiency without decreasing accuracy.

Metalinguistic Monstrosity and Displaced Communications

David Kaplan's semantic theory for indexicals yields a distinct logic for indexical languages that generates contingent a priori truths. These special truths of the logic of indexicals include examples like "I am here now", an utterance of which expresses a contingent state of affairs and yet which, according to Kaplan, cannot fail to be true when it is uttered. This claim is threatened by the problem of displaced communications: answerphone messages, for example, seem to facilitate true instances of the negation of this supposed logical truth as they allow the agent of the message to no longer be at the location of the message when it is encountered by an audience. Many such displaced communications can be identified in everyday natural language uses of indexicals. Recent discussion has suggested that Kaplan's error is to be overly restrictive in the possible contexts of utterance his semantic theory recognizes, as he fails to acknowledge the possibility of utterances that occur at a context distinct from that in which they are constructed. I reject this diagnosis and defend Kaplan's semantic theory. Displaced communications, I argue, are best understood as resulting from a pragmatically introduced metalinguistic context-shifting operation and hence do not demand revision of Kaplan's semantic theory. I provide an analysis of the pragmatic process underlying this operation and make the case for its merits over those of rival accounts of displaced communications.

Battery energy storage train routing and security constrained unit commitment under solar uncertainty

The location of solar parks far from load areas may lead to transmission congestion and thus solar curtailment for secure system operation. Battery energy storage (BES) Train as mobile storage can transmit solar energy from site to load centers using a transport network while relieving lines from congestion. Therefore, stochastic security-constrained unit commitment (SCUC) with BES Train is modeled in this paper under solar uncertainty and N-1 critical line contingency. Time-space network models transportation constraints of BES Train routing problem. To reduce the computational burden, this paper proposes modeling of line outage distribution factor (LODF) for DC power flow that reduces the nonzero coefficients of post-contingency network constraints. The benders decomposition technique simplifies stochastic optimization for the mixed-integer linear programming (MILP) problem. BES Train integrated modified IEEE reliability test and 118-bus system is investigated as a case study. Simulations evaluate the effect of BES Train, solar uncertainty and critical line contingency state with LODF on operation costs, BES Train scheduling, solar curtailment, congestion and computational time. The proposed model shows that BES Train is an economical option for large solar integration to reduce transmission congestion and curtail solar power effectively.

“How Does Nature Deify Us”

“How Does Nature Deify Us”

PROPERTY CRIME INCIDENCE AND PATTERNS IN MALAYSIA FROM 2007 TO 2017

Crime is a social problem faced by all communities and ranges from property loss or damage to violent events such as murder and robbery. Crime trends are associated with many factors including mental health, unemployment rates, educational status and policing strategies. In this article, we provide property crime datasets for Malaysia from 2007 to 2017. The data were gathered from all reported cases at district police stations and contingent (state and federal territory levels) headquarters. This information was extracted from the Malaysian Police Reporting System (PRS) and divided into five categories; theft, car theft, motorcycle theft, van/lorry/heavy machinery theft and housebreaking. Overall, there were 1,361,320 property crime cases were reported from 2007 to 2017. Theft and motorcycle theft were observed to be the most common types of property crime in Malaysia. In general, property crime cases continue to decline from 163,317 cases in 2007 to only 77,562 in 2017 due to government initiatives and a proactive policing policy. The same downward trend in overall property crime was also observed at state and federal territory levels and is mainly due to a drop in the volume of theft and motorcycle theft cases.

Causes, Contingency and Freedom: A Reply to Anscombe, Mumford and Anjum

This paper takes Anscombe, Mumford and Anjum as key interlocutors for an exploration of the causality involved in our understanding of free will. Anscombe tried to disentangle causality from necessary determination in order to make room for free will, and a first section points to the historical and theological background of this entanglement. However, what is also crucially at stake is the relation between time and causality whereby this paper advocates a shift from a diachronic to a synchronic conception. This synchronic conception of the contingency of free will is then argued to be superior to Mumford and Anjum’s dispositional modality in providing the libertarian desiderata of alternative possibilities and ultimate authorship, and gives us a picture of a permanent causal tug-of-war in the present. The final section then points out that this puts persons and their contingent decisions partly in the role of being an explanans for, rather than an explanandum of, any current contingent state of affairs.

Review of Coronavirus disease- 2019 (COVID-19) in Iraq

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV 2) or 2019 novel coronavirus (2019-nCoV) is quickly spreading to the rest of the world, from its origin in Wuhan, Hubei Province, China. And becoming a global pandemic that affects the world's most powerful countries. The goal of this review is to assist scientists, researchers, and others in responding to the current Coronavirus disease (covid-19) is a worldwide public health contingency state. This review discusses current evidence based on recently published studies which is related to the origin of the virus, epidemiology, transmission, diagnosis, treatment, and all studies in Iraq for the effect of covid-19 diseases, as well as provide a reference for future researchers. The findings of this review show significant differences across gender, age group, area of residence, environmental agents (temperature, humidity), and people with chronic diseases (hypertension, diabetes mellitus, heart disease, respiratory disorders, and immunocompromised disease). To control the pandemic, information about COVID-19 was disseminated to people, including wearing a face mask and using a social distancing strategy as an effective tool for controlling COVID-19. More education and progress are required to convince the public that the vaccine is both effective and safe.

National Survey of COVID-19 Infections Among Head Surgical Specialists Regarding Orthopedic Foot and Ankle Surgeons in Mexico

Category:OtherIntroduction/Purpose:The health contingency due to COVID19 has represented an unprecedented state of health contingency with implications for the economy and public health. There is a concern in the medical community regarding the risk of contagion of COVID19. Recently, the occupational risk of contagion by COVID19 has been described in surgical specialties that involve proximity to the face and airway of the patient Ophthalmology and Otorhinolaryngology and head and neck surgery (ENT). A possibility has been raised that Foot and Ankle joint surgeons have some occupational protection due to the distance greater than 1m with respect to the patient's airway during surgical activities. The objective of this study is to compare COVID-19 infections referred by different surgical specialties and subspecialties.Methods:An observational, cross-sectional, and descriptive study will be carried out in which a survey will be applied to 134 surgical specialists divided into 3 groups (ophthalmology, ENT, and orthopedic surgeons performing foot and ankle surgery) during the months of August to September 2020.Percentage prevalences of each variable to be evaluated will be obtained, likewise, a Chi- square test will be applied to determine statistical differences between the proportions of referred positivity in the 3 groups. This research study was reviewed by our institution and hospital research ethics committee. All participants gave their informed consent at the time of conducting the survey, as well as allowing the use of their responses for the purposes of this project.Results:A total of 134 surveys pertaining to 30, 69, and 35 Mexican ophthalmology, ENT, and orthopedic surgeons who perform foot and ankle surgery respectively were evaluated. The geographical distribution of the surveys is identified in figure 1. After the statistical analysis, non-significant statistical differences (p> 0.32) were documented in the proportion of infections between ophthalmologists or ENTs, with respect to the proportion of infections referred by COVID-19 in the group of Orthopedic foot and ankle surgeons surveyed.Conclusion:When analyzing the results of this survey-type study, it is possible to establish that the statistically non-significant differences between the proportions of infections of the groups of specialists evaluated could suggest that the working distance with respect to the patient's airway is not a protective factor for contagion. by COVID-19. Preventive strategies, as well as the vaccination of health personnel involved in patient care, are essential.

Prioritization of Transmission Network Components Based on their Failure Impact on Reliability of Composite Power Systems

This paper proposes an efficient method to identify the importance of transmission network components from the network’s reliability perspective. The proposed method is able to reveal the weak points of the network and can be employed as useful tool by power system planners to identify where investments should be made to increase the overall system reliability. The proposed approach has two main stages, including evaluation of the network contingency states and a sensitivity analysis which shows the link between reliability of each component and overall system reliability. Unlike the similar methods in this area and with the help of two reasonable simplifications, the proposed method can be employed to real transmission networks with acceptable computational burden. The proposed method is implemented on two test systems including the IEEE Reliability Test System (IEEE RTS) and the Roy Billinton Test System (RBTS). The obtained results demonstrate the efficiency of the proposed approach.

A MODAL-CAUSAL ARGUMENT FOR A CONCRETE NECESSARY OBJECT

Suppose that it is metaphysically possible that the mereological fusion of all contingent states of affairs has a cause. Whatever the nature of the state of affairs that causes such mereological fusion, it should be metaphysically necessary because, otherwise, it could be part of the mereological fusion it causes. It is possible, then, that there is at least one necessary state of affairs. This state of affairs is a causal relatum, so it must include at least one concrete necessary object. But if something is possibly necessary, then it is necessary because it is not metaphysically contingent whether something is necessary or doesn't. Then, it results that it is metaphysically necessary that there is, at least, a concrete necessary object. This work presents and discusses this argument.

Data-driven power system reliability evaluation based on stacked denoising auto-encoders

The increasing penetration of renewable energy resources in power systems inadvertently leads to a surge in the number of random states. The calculation of optimal load shedding for all the proliferated states is rather overwhelming. It has been considered a bottleneck in the reliability evaluation process. To address this issue, a deep-learning-based approach is proposed to evaluate system reliability more efficiently considering the fluctuation of generation and loads. In the proposed power flow model, a stacked denoising auto-encoder (SDAE) serves as a multilayer neural network for the deep-learning process. Its stacked structure and encoding-decoding recursion enable it to extract high-order features even from non-linear equations. The features of contingency states are crucial to directly acquire the minimum load curtailment without the time-consuming optimal power flow (OPF). The after-trained model is applied to states simulated with the Monte-Carlo method in the RTS-79 system. The numerical result reveals the great advantage of the SDAE-based method in computation time while ensuring high accuracy. As an alternative way to classic OPF algorithms, it can be integrated with the impact-increment method and other state selection approaches.

A fast optimal load shedding method for power system reliability assessment based on shadow price theory

The optimal load shedding calculations of an enormous number of contingency states are the most challenging impediments for power system reliability assessment, especially in a large-scale system with multiple types of loads. To deal with that, this paper proposes a fast method that accelerates the calculation of optimal load shedding based on the shadow price. This method calculates the optimal load shedding of systems by shadow-price-based linear functions, rather than the time-consuming OPF algorithms. The hundred percentage criterion is used to look for the matching shadow price of states. Case studies are performed on the RTS-79 system. The results show that the proposed methodology can significantly simplify the solving process and reduce the calculation time.

Infrastructural territorialisations: Mega-infrastructures and the (re)making of Kenya

This paper, based on historical and contemporary dynamics of railway infrastructures in Kenya, analyses how mega-infrastructures are central in state practices of infrastructural territorialisation – an infrastructure-based production of territoriality as a historically and geographically specific form of spatio-political order and organisation, imbued with social tensions, stemming from the state-led imposition of a techno-politics onto its territory. Focusing on territorial and political objectives of the state advanced through the Uganda Railway and the Standard Gauge Railway, the paper demonstrates how both of these projects have been central in colonial and contemporary practices of infrastructural territorialisation, albeit in mercurial ways that do not fully represent original techno-political intensions of the state. This discussion, first, highlights how megaprojects – although primarily analysed by recent geographical scholarship as advancing contemporary geographies of global capitalism – also contingently coalesce with state (re)territorialisation practices. Second, undertaking these analyses in the Kenyan context, the paper shows how, despite shared historical dynamics of contingent state territorialisation – and the reconstitution of racial and socio-economic inequalities, advanced through megaprojects that in Kenya are socially interpreted through historical experiences of colonialism – current infrastructural territorialisations are also different; whilst the colonial territorialisation of Kenya emerged as relatively unchallenged, its present state territory-making is undermined by both the global character of megaprojects and the external actors that the state relies on for its practices of infrastructural territorialisation.