Transient Stability Preventive Control of Wind Farm Connected Power System Considering the Uncertainty

To address uncertainty as well as transient stability constraints simultaneously in the preventive control of windfarm systems, a novel three-stage optimization strategy is established in this paper. In the first stage, the probabilisticmulti-objective particle swarm optimization based on the point estimate method is employed to cope with thestochastic factors. The transient security region of the system is accurately ensured by the interior point methodin the second stage. Finally, the verification of the final optimal objectives and satisfied constraints are enforcedin the last stage. Furthermore, the proposed strategy is a general framework that can combine other optimizationalgorithms. The proposed methodology is tested on the modified WSCC 9-bus system and the New England 39-bussystem. The results verify the feasibility of the method.

Framework for Preventive Control of Power Systems to Defend Against Extreme Events

Enhancing power system resilience against extreme events is becoming increasingly critical. This paper discusses a unified framework for preventive control of power systems to enhance system resilience, which includes three parts: resilience assessment, resilience grading, and resilience enhancement. First, the resilience assessment contains facility-level and system-level resilience assessment. The concept of fragility curve is used in the facility-level resilience assessment. Various resilience indices are developed in system-level resilience assessment to roundly depict the impacts of extreme events on power systems and determine the system resilience. On this basis, the resilience is divided into different levels by resilience grading strategy, which can efficiently quantify the severity of the impact of extreme events and provide decision-making for the resilience enhancement strategies. Then, control strategies for enhancing power system resilience are also divided according to different resilience levels. A controlled islanding based preventive control is proposed to enhance system resilience, which aims to strengthen the first defensive line of power systems to deal with extreme events. Finally, taking the typhoon disaster in extreme events as an example, two tests carried out with two typhoons demonstrate the efficiency of the proposed method.

Distributed Deep Reinforcement Learning-based Approach for Fast Preventive Control Considering Transient Stability Constraints

Preventive transient stability control is an effective measure for the power system to withstand high-probability severe contingencies.It is mathematically an optimal power flow problem with transient stability constraints.Due to the constraints involved for differential algebraic equations of transient stability,it is difficult and time-consuming to solve this problem.To address these issues,this paper presents a novel deep reinforcement learning(DRL)framework for preventive transient stability control of power systems.A distributed deep deterministic policy gradient is utilized to train a DRL agent that can learn its control policy through massive interactions with a grid simulator.Once properly trained,the DRL agent can instantaneously provide effective strategies to adjust the system to a safe operating position with a near-optimal operational cost.The effectiveness of the proposed method is verified through numerical experiments conducted on a New England 39-bus system and NPCC 140-bus system.

Analysis of debris flow control effect and hazard assessment in Xinqiao Gully,Wenchuan M_(s)8.0 earthquake area based on numerical simulation

Xinqiao Gully is located in the area of the 2008 Wenchuan M_(s)8.0 earthquake in Sichuan province,China.Based on the investigation of the 2023"6-26"Xinqiao Gully debris flow event,this study assessed the effectiveness of the debris flow control project and evaluated the debris flow hazards.Through field investigation and numerical simulation methods,the indicators of flow intensity reduction rate and storage capacity fullness were proposed to quantify the effectiveness of the engineering measures in the debris flow event.The simulation results show that the debris flow control project reduced the flow intensity by41.05%to 64.61%.The storage capacity of the dam decreases gradually from upstream to the mouth of the gully,thus effectively intercepting and controlling the debris flow.By evaluating the debris flow of different recurrence intervals,further measures are recommended for managing debris flow events.

Technical Points of Green Prevention and Control Technology of Major Diseases and Pests in Lixian Rhubarb(Rheum palmatum L.)

Based on different types of diseases,pests and weeds in the whole growth period of rhubarb(sowing period-harvesting period),the corresponding green prevention and control technology is proposed,aiming to further reduce the application amount of pesticides and fertilizers in the production of medicinal sources of Lixian rhubarb during the"14 th Five-Year Plan"period.The results will provide a theoretical basis for increasing the promotion and application of agricultural prevention and control(including disease-resistant varieties,ecological regulation),physical prevention and control,biological prevention and control measures,thus ensuring effective protection of the ecological environment,green,healthy and sustainable development of traditional Chinese medicine agriculture in Longnan,and source quality of authentic medicinal materials.

Practice of Infection Prevention and Control Strategies in Risk Departments during the COVID-19 Epidemic

Objective: To explore the practice and application of infection prevention and control strategies in risk departments during the COVID-19 epidemic, and to formulate the infection prevention and control measures to provide advice and guidance in risk departments. Methods: According to the latest plan of diagnosis and treatment, prevention and control issued by the National Health Commission, expert advice and consensus, combined with the actual situation in our hospital, a series of infection prevention and control measures of COVID-19 in risk department was formulated. Results: During the epidemic period, the prevention and control measures of nine risk departments including emergency operation, anesthesiology, endoscopy center, blood purification center, otolaryngology, stomatology, medical imaging department, medical cosmetology department and pulmonary function room were established from six aspects, including pre-examination and screening, medical technology control, personnel management, personal protection, environmental disinfection, medical waste disposal, etc. Conclusion: During the epidemic period, the infection prevention and control strategy of risk departments is one of the key links to control the spread of the epidemic, and risk departments must pay attention to and strictly implement various infection prevention and control measures.

Prevention and Control Strategies of Nosocomial Infection and Effectiveness Evaluation in a Tertiary Teaching Hospital during the Epidemic of COVID-19

Objective: To evaluate the role of prevention and control strategies for nosocomial infection in a tertiary teaching hospital during the sudden outbreak of Corona Virus Disease 2019 (COVID-19). Methods: The hospital initiated an emergency plan involving multi-departmental defense and control. It adopted a series of nosocomial infection prevention and control measures, including strengthening pre-examination and triage, optimizing the consultation process, improving the hospital’s architectural composition, implementing graded risk management, enhancing personal protection, and implementing staff training and supervision. Descriptive research was used to evaluate the short-term effects of these in-hospital prevention and control strategies. The analysis compared changes in related evaluation indicators between January 24, 2020 and February 12, 2020 (Chinese Lunar New Year’s Eve 2020 to lunar January 19) and the corresponding lunar period of the previous year. Results: Compared to the same period last year, the outpatient fever rate increased by 1.85-fold (P P Conclusion: The nosocomial infection prevention and control strategies implemented during this specific period improved the detection and control abilities for the COVID-19 source of infection and enhanced the compliance with measures. This likely contributed significantly to avoiding the occurrence of nosocomial infection.

Comprehensive Prevention and Control Technology of Vegetable Diseases and Pests in Shandong Province

An in-depth research and practice has been conducted on vegetable diseases and pests in Shandong Province,and the principles of comprehensive and ecological control of diseases and pests are put forward,including agricultural control measures such as crop rotation,field cleaning,fertilizer and water management,physical control measures such as catching and killing,trapping,blocking,photoelectric energy treatment,biological control measures such as the use of natural enemies,pathogenic microorganisms,other beneficial organisms and metabolites,and scientific and rational chemical control measures.Comprehensive prevention and control not only controls vegetable diseases and pests effectively,but also protects the ecological environment.

The Research on the Paths of Popular Science Education about Myopia Prevention and Control among College Students in the Context of Shifting the Focus Forward

Currently, the number of myopic people in China has reached as high as 600 million, and it shows a trend of “early onset, high incidence, and a high degree of severity”. The issue of myopia among children and adolescents has attracted widespread attention from all sectors of society. Comprehensive myopia prevention and control efforts have been launched nationwide. Popular science education, vision screening, and improving visual environments are effective measures for preventing myopia. However, among the target audience for comprehensive myopia prevention and control, the preschool children group has been neglected, and the work of myopia prevention and control for this group has been significantly weakened and marginalized. Due to insufficient awareness of prevention and control, the hyperopia reserve in the preschool children group is being continuously depleted, leading to the early onset of myopia. In light of this situation, the focus of myopia prevention and control needs to shift forward, and it is worth exploring and pondering how college students with a background in optometry can develop entertaining and engaging popular science education materials and methods.

A preventive control strategy for static voltage stability based on an efficient power plant model of electric vehicles

With the increasing integration of wind farms and electric vehicles(EVs)in power systems,voltage stability is becoming more and more serious.Based on vehicle-to-grid(V2G),an efficient power plant model of EVs(E-EPP)was developed to estimate EV charging load with available corresponding response capacity under different charging strategies.A preventive control strategy based on E-EPP was proposed to maintain the static voltage stability margin(VSM)of power system above a predefined security level.Two control modes were used including the disconnection of EV charging load(‘V1G’mode)and the discharge of stored battery energy back to power grid(‘V2G’mode).A modified IEEE 14-bus system with high penetration of wind power and EVs was used to verify the effectiveness of preventive control strategy.Simulation results showed that the proposed strategy can not only improve the static voltage stability of power system with considerable wind generation,but also guarantee the travelling comfort for EV owners.

Preventive Control for Power System Transient Security Based on XGBoost and DCOPF with Consideration of Model Interpretability

This paper proposes a new approach for online power system transient security assessment(TSA)and preventive control based on XGBoost and DC optimal power flow(DCOPF).The novelty of this proposal is that it applies the XGBoost and data selection method based on the 1-norm distance in local feature importance evaluation which can provide a certain model interpretability.The method of SMOTE+ENN is adopted for data rebalancing.The contingency-oriented XGBoost model is trained with databases generated by time domain simulations to represent the transient security constraint in the DCOPF model,which has a relatively fast speed of calculation.The transient security constrained generation rescheduling is implemented with the differential evolution algorithm,which is utilized to optimize the rescheduled generation in the preventive control.Feasibility and effectiveness of the proposed approach are demonstrated on an IEEE 39-bus test system and a 500-bus operational model for South Carolina,USA.

Analytical Representation of Data-driven Transient Stability Constraint and Its Application in Preventive Control

Accurate transient stability assessment(TSA) and effective preventive control are important for the stable operation of power systems. With the superiorities in precision and efficiency, data-driven methods are widely used in TSA nowadays. Data-driven TSA model can be adopted in the stability constraints of preventive control optimization, but existing methods are mostly iteration-based ones, which may result in low efficiency, sometimes even non-convergence. In this paper,an analytical representation method of data-driven transient stability constraint is proposed based on a non-parametric regression model built for TSA. Key feature extraction and dominant sample selection are proposed to reduce the scale of the TSA model, and bi-level linearization is applied to further modify it.Optimal preventive control model is then formulated as a mixed-integer linear program(MILP) problem with the linearized analytical data-driven transient stability constraint, which can be solved without iterations. An overall procedure of datadriven TSA and preventive control is finally developed. Case studies show that the proposed method has high accuracy in TSA and can achieve effective preventive control of power system with high efficiency.

Combustion mechanism and control approaches of underground coal fires:a review

With the large-scale mining of coal resources,the huge economic losses and environmental problems caused by underground coal fires have become increasingly prominent,and the research on the status quo and response strategies of underground coal fires is of great significance to accelerate the green prevention and control of coal fires,energy conservation and emission reduction.In this paper,we summarized and sorted out the research status of underground coal fires,focused on the theoretical and technical issues such as underground coal fire combustion mechanism,multiphysics coupling effect of coal fire combustion,fire prevention and extinguishing technology for underground coal fires,and beneficial utilization technology,and described the latest research progress of the prevention and control for underground coal fire hazards.Finally,the key research problems in the field of underground coal fire hazards prevention and control were proposed in the direction of the basic theory,technology research,comprehensive management and utilization,with a view to providing ideas and solutions for the management of underground coal fires.

Construction Technology and Safety Risk Control Measures of Deep Foundation Pit Excavation

Deep foundation pit excavation is a basic and key step involved in modern building construction.In order to ensure the construction quality and safety of deep foundation pits,this paper takes a project as an example to analyze deep foundation pit excavation technology,including the nature of this construction project,the main technical measures in the construction of deep foundation pit,and the analysis of the safety risk prevention and control measures.The purpose of this analysis is to provide scientific reference for the construction quality and safety of deep foundation pits.

Looking up Prescriptions to Treat Infectious Disease:Anti-epidemic Books of Medical Formularies and Epidemic Prevention and Control in the Qing Dynasty

Copying,compiling,publishing,disseminating,and referencing anti-epidemic books of medical formularies were common activities during the outbreak of epidemics in the Qing dynasty.Its emergence,motivated by epidemic disease again and again,was important component parts of epidemic prevention and control.They played a unique role as media on affairs such as treating patients suffering from infectious diseases,mobilizing peoples to make contributions to anti-epidemic activities,integrating and popularizing knowledge of epidemic prevention.Anti-epidemic books of medical formularies were important to link peoples,things,and substances related with epidemic prevention and control,and were a kind of motivation to actively deal with the infectious disease,control the epidemic,and maintain health.Compared to other common measures,anti-epidemic books of medical formularies participated in many prevention and control practices deeply,which actually built a low cost,spontaneous,dispersed and non-institutional system to respond to epidemic,and the system had characteristics of stronger conductibility,bigger coverage area,and better external benefits.

Species and Control Techniques of Main Diseases and Insect Pests of Camellia oleifera in Anhui Province

[Objectives]The paper was to master the species,incidence regularity and control techniques of main diseases and insect pests of Camellia oleifera in Anhui Province.[Methods]The species of main diseases and insect pests of C.oleifera in major C.oleifera afforestation bases and seedling bases in Anhui Province were investigated through field survey and literature search.Afterwards,the symptom characteristics,occurrence regularity and harms of diseases and insect pests were analyzed,and scientific and reasonable control techniques were put forward.[Results]The main diseases of C.oleifera in Anhui Province were soft rot disease,blister blight,anthracnose,sooty blotch,etc.,and the main insect pests were Euproctis pseudoconspersa,Biston marginata,Hypomeces squamosus,Curculio chinensts,Chrenoma atritarsis,etc.The control techniques mainly included ecological regulation,physical prevention and control,chemical prevention and control,and biological prevention and control.[Conclusions]The results will promote the high-quality development of C.oleifera industry in Anhui Province,and contribute to the improvement of China s edible vegetable oil supply and national grain and oil security.

Occurrence Characteristics and Prevention and Control Measures of Spodoptera frugiperda in Maize

Based on practical work experience,this paper analyzed the occurrence characteristics and control measures of Spodoptera frugiperda in maize.The measures including forecasting and early warning,regional prevention and control,agricultural prevention and control,physical prevention and control,chemical prevention and control,and biological prevention and control can effectively control the damage of S.frugiperda and guarantee the safety of food production.The results will provide some reference for the prevention and control of S.frugiperda.

Technical Studies of Controlling Jujube Witches Broom Disease with Resistant Rootstock

[Objectives]The paper was to screen and identify the control effect of resistant rootstock on jujube witches broom disease.[Methods]The seeds or branches of disease-free plants were collected from wild jujube bushes infected by witches broom disease,and 5434 seedlings were obtained by sowing or cutting.The virus was inoculated by grafting diseased bark.After 6 years of preliminary screening,40 plants with resistance to jujube witches broom disease were obtained.Taking these resistant plants as the rootstocks,the susceptible variety‘long red jujube’was grafted at a height of 40 cm.When the plants grew to appropriate thickness,diseased bark was grafted to‘long red jujube’and rootstock to transmit the virus.After 18 years of observation and judgment,4 rootstock strains with high resistance or immunity to jujube witches broom disease were finally determined,namely 90801,90803,90806 and 908011.The susceptible variety‘long red jujube’was grafted to 4 rootstocks and inoculated the virus through diseased bark grafting method.[Results]The resistant rootstock had obvious disease resistance effect.When the branches of 90801 and 90803 rootstocks were grafted to the trunk of diseased trees,the symptoms of jujube witches broom disease gradually alleviated till disappeared.[Conclusions]Using germplasm with high resistance or immunity to jujube witches broom disease as rootstock can effectively prevent the spread of jujube witches broom disease,and bridging the trunk of diseased trees with branches from resistant rootstock has certain therapeutic effect.

Occurrence Factors and Efficient Green Prevention and Control Technology of Peanut Stem Rot Caused by Sclerotium rolfsii in Southern Mountainous Area of Shandong Province

Peanut stem rot caused by Sclerotium rolfsii is a soil-borne disease,and it has become the main disease of peanut in Yimeng mountainous area.S.rolfsii survives the winter as mycelia and sclerotia in soil and debris,becoming the primary source of infection in the following year.The disease resistance of peanut varieties,high temperature and humidity,and cultivation measures are the pathogenic factors affecting the occurrence of peanut stem rot.The disease can be effectively controlled by screening disease-resistant varieties and seed chemical treatment,improving soil by deep tillage and crop rotation,carrying out flowing water management of affected field,cutting off transmission routes,and strengthening seed dressing and triple spraying control.

Overview of Occurrence,Prevention and Control of Panonychus citri in China

In order to further promote the prevention and control research of Panonychus citri and improve its control effect,this paper summarizes the main influencing factors of the outbreak,main control technology and drug resistance of P.citri,and puts forward the research focus and control strategy.