Distribution Line Longitudinal ProtectionMethod Based on Virtual Measurement Current Restraint

As an effective approach to achieve the“dual-carbon”goal,the grid-connected capacity of renewable energy increases constantly.Photovoltaics are the most widely used renewable energy sources and have been applied on various occasions.However,the inherent randomness,intermittency,and weak support of grid-connected equipment not only cause changes in the original flow characteristics of the grid but also result in complex fault characteristics.Traditional overcurrent and differential protection methods cannot respond accurately due to the effects of unknown renewable energy sources.Therefore,a longitudinal protection method based on virtual measurement of current restraint is proposed in this paper.The positive sequence current data and the network parameters are used to calculate the virtual measurement current which compensates for the output current of photovoltaic(PV).The waveform difference between the virtual measured current and the terminal current for internal and external faults is used to construct the protection method.An improved edit distance algorithm is proposed to measure the similarity between virtual measurement current and terminal measurement current.Finally,the feasibility of the protection method is verified through PSCAD simulation.

Changes of coastline and tidal flat and its implication for ecological protection under human activities: Take China’s Bohai Bay as an example

The change processes and trends of shoreline and tidal flat forced by human activities are essential issues for the sustainability of coastal area,which is also of great significance for understanding coastal ecological environment changes and even global changes.Based on field measurements,combined with Linear Regression(LR)model and Inverse Distance Weighing(IDW)method,this paper presents detailed analysis on the change history and trend of the shoreline and tidal flat in Bohai Bay.The shoreline faces a high erosion chance under the action of natural factors,while the tidal flat faces a different erosion and deposition patterns in Bohai Bay due to the impact of human activities.The implication of change rule for ecological protection and recovery is also discussed.Measures should be taken to protect the coastal ecological environment.The models used in this paper show a high correlation coefficient between observed and modeling data,which means that this method can be used to predict the changing trend of shoreline and tidal flat.The research results of present study can provide scientific supports for future coastal protection and management.

The evolution of central environmental protection inspection policy attention in China: An investigation based on inspection reports

The central environmental protection inspection (CEPI) system in China is a significant institutional innova‐tion in national environmental governance. The CEPI applies a joint supervision strategy to address salient en‐vironmental issues and strictly enforce the environmental responsibilities of local governments. This study col‐lects and organizes CEPI inspection reports covering three stages that encompass the first round, the “look back”, and the second round, applying text analysis to obtain sample data and conduct statistical quantifica‐tion of word frequency in inspection reports and identify notable changes. The study explores the allocation of CEPI attention between policy objectives and the intensity of policy instruments. We determine that in con‐junction with public opinion feedback, the CEPI conducts targeted inspections and focuses more on pollutant governance, which has high severity and can be addressed quickly. The CEPI fills the gap of normalized gover‐nance with a campaign-style governance approach. Regarding the intensity of policy measures, the CEPI pri‐marily uses economic incentive policy instruments, supplemented by command-and-control and public guid‐ance approaches, advancing the sustainability of regulatory effectiveness through economic, social, and politi‐cal activities. This study extends knowledge in the field of CEPI policy priorities and implementation, expand‐ing the literature related to outcomes of environmental policy in developing countries.

Research on Protection Methods of Historic and Cultural Villages in Zhejiang Province

By the investigation of a few historical and cultural villages in Zhejiang Province,some problems during the process of protecting these villages were found,like similar construction pattern,coarse quality of construction,etc. which caused that villages were losing their characters. For this situation,the protection method of historical cultural villages was put forward,which was that to connect excavating character of different village with maintaining spatial fabrics of historical villages,and that different classes of building should have corresponding protection approach. Some advices were proposed for repairing and promoting historic and cultural elements,natural environment,and constructing infrastructure in the village,which will provide a reference for the construction of other historical and cultural villages.

Theories and Methods of Landscape Architecture Heritage Protection

This paper firstly made an overview of foreign and domestic theories and methods of landscape architecture heritage protection.It studied the landscape architecture heritage from policies and regulations,investment management,talent cultivation,and popular science education.Then,it discussed problems of landscape architecture heritage protection in China:lack of legislation,weak awareness of heritage resources,overdevelopment of heritage resources,and vacancy in management and monitoring of heritage resources.Finally,it came up with recommendations that competent authorities of Chinese government should attach greater importance to heritage management,talent cultivation,and fund input,integrate with advanced management methods of developed countries,and exploring a landscape architecture heritage protection and management mode suitable for national conditions of China at levels of thought,methods,and technology.

Experimental Research on the Erosion Pattern and Protection Using the Extended Modelling Method

In the paper the extended modelling method with serial sands is used in an experimental research on the erosion patterns at the discharge outlet of a beach Hua-Neng power plant. The theoretical basis for the extended modelling method with serial sands is systematically presented in the paper and the method has been successfully employed in the sediment experiment of coastal works. According to the Froude Law, the model is designed to be a normal one with movable bed, the geometric scale lambda(L) = lambda(H) = 15, and three scales of sediment grain size are chosen, i.e., lambda(d1) = 0.207; lambda(d2) = 0.393; and lambda(d3) = 0.656. The median particle diameter of sea beach prototype sand d(50p) = 0.059 mm and the dis-changed water flow of the power plant is 21.7 m(3) / s. Three types of natural sea sands have been chosen as the serial modelling sands to extend the simulation of the prototype, thus replacing the conventional test in which artificial lightweight sands are used. As a result, this method can not only reduce the cost significantly, but also it is an advanced technique easy to use. Upon a series of tests, satisfactory results have been obtained.

Finite Element Method Applied to Fuse Protection Design

In a poloidal field （PF） converter module, fuse protection is of great importance to ensure the safety of the thyristors. The fuse is pre-selected in a traditional way and then verified by finite element analysis. A 3D physical model is built by ANSYS software to solve the thermal- electric coupled problem of transient process in case of external fault. The result shows that this method is feasible.

Surface Protection Methods against Fretting Fatigue for TC11 Titanium Alloy

The influence of various surface coatings, including flame sprayed Cu、 plasma sprayed Cu Ni In、 exploding sprayed WC/Co Ⅰ and plasma sprayed WC/Co Ⅱ, on fretting fatigue resistance for TC11 titanium alloy at 20℃ and 500℃ is studied. The results show that the plasma sprayed WC/Co Ⅱ coating has good protection performance and makes the fretting fatigue strength of TC11 titanium alloy raise 40% at both 20℃ and 500℃. The fretting fatigue strength of TC11 alloy with Cu coating is increased about 62% at 20℃, but the protection performance at 500℃ is not so good as that at 20℃.

Computation of Protection Zone of a Lightning Rod Using Method of Moments and Monte Carlo Integration Technique

An accurate determination of lightning protection zone is an important issue in the analysis and design of an appropri-ate lightning protection system. This paper presents a fast and accurate protection zone determination methodology for metallic lightning rod. The methodology is based on Quasi Monte Carlo Integration technique applied to Method of Moments (MoM) solution of Integral Equations. As an example, solution of the integral equation for unknown charge distribution on lightning rod is obtained. The electric field in the region surrounding the rod is then computed and the protection zone plotted accordingly. The effect of the thickness of the rod on the protection zone is also studied.

Crop Protection Compendium检索系统的应用

通过对国际农业和生物科学中心(CABI)编辑出版的作物保护大全检索系统(CropProtectionCompendium)进行研究,阐述了该检索系统的概况、检索界面和检索方法。

Research on Hidden Failure Reliability Modeling of Electric Power System Protection

Aiming at digital relay protection system, a novel hidden failure Markov reliability model is presented for a single main protection and double main protection systems according to hidden failure and protection function under Condition-Based Maintenance (CBM) circumstance and reliability indices such as probability of protection system hidden failure state are calculated. Impacts of different parameters (containing impacts of human errors) to hidden failure state probability and the optimal measures to improve reliability by variable parameter method are also analyzed. It’s demonstrated here that: Compared to a single main protection, double main protection system has an increased hidden failure probability, thus the real good state probability decreases, two main protections’ reliability must be improved at the same time, so configuration of the whole protection system for the component being protected can’t be complicated. Through improving means of on-line self-checking and monitoring system in digital protection system and human reliability, the real application of CBM can decrease hidden failure state probability. Only through this way can we assure that the protection systems work in good state. It has a certain reference value to protection system reliability engineering.

An Analysis of the Legal System for the Protection of Marine Resources in China

In order to realize the orderly development and rational use of marine resources,construct a new marine economic development model,effectively adjust the relationship between marine resource protection and social production,and promote the legalization and institutionalization of marine resource protection.Based on the reality,this article attempts to explore the ways and means of improving and constructing the legal system for the protection of marine resources from multiple dimensions.It aims to form a complete marine resource development system from the legal level and provide legal guarantee for the development of marine economy.

Optimization of Freeze-drying Protective Agents for Lactobacillus plantarum KLDS1.0391 by Response Surface Methodology

In this study, the Single Factor Test（SFT） was used to optimize the pre-freezing conditions of L. plantarum KLDS1.0391（KLDS1.0391）. Further, the Freeze-Drying Protective Agents（FDPA） of KLDS1.0391 was optimized by Response Surface Methodology（RSM）. The optimum pretreatment conditions were as the follows： initial concentration of KLDS1.0391 was 1011 CFU · m L-1 and KLDS1.0391 was pre-freezed at –80℃ for 8 h to achieve the survival rate of 46.21%. The main components of FDPA were skim milk, sucrose, sodium glutamate and Tween-80. And the influence of four factors on the survival rate of KLDS1.0391 in freeze-drying was in order as the follows： skim milk〉sucrose〉Tween-80〉sodium glutamate. The optimal FDPA composition was skim milk 11.3%, sucrose 9.8%, sodium glutamate 5.1% and Tween-80 0.2%. Under the above conditions, the survival rate of the cells was 82.98%. Comparing the predicted values, the relative error was 0.37% and the difference was not significant, which indicated that the established model could effectively reflect the actual protection of FDPA to KLDS1.0391.

Fault diagnosis and protection of motors in coal shearer

Symmetrical components method is employed in analysis of the characteristic motor faults.Motor protection method is put forward based on detecting positive sequence,negative sequence and zero sequence current.And problems of lack of motor overload capacity in existing mining motor protection system,impact of dynamic current on stage and definite-time delay operation and inaccuracy of criterion phase failure protection are analyzed.The unbalanced faults protection and inverse-time overload protection,which can make protection time change with the current movement,are proposed.The above problems can be solved,and the reliability and intelligent of coal shearer are improved.

Study on the Effect of Multi-Type Current Transformers Hybrid Operation on Differential Protection of the Bus Based on Dynamic Simulation

This paper analyzes characteristics of multi type current transformers hybrid operation for each branch of the bus and their effects on differential protection of the bus. By theoretically analyzing transmission characteristics of multi type current transformers and their influence factors, we study the dynamic model testing method of multi type current transformers for the bus, and design 3 kinds of testing schemes by making the equivalent model based on the field of P-level current transformer, TPY-level current transformer and electronic current transformer, and build the hybrid operation testing platform of multi type current transformers. Finally, we compare and analyze the transmission characteristics difference of multi type current transformers on the same branch and the characteristics difference of hybrid operation in two successive external faults, analyze the cause behind the differences, and put forward the corresponding improvement measures.

Thermal and Structural Behaviour of Offshore Structures with Passive Fire Protection

In offshore structures,hydrocarbon fires cause the structure to loose its rigidity rapidly and this leads to structural integrity and stability problems.The Passive Fire Protection(PFP)system slows the transfer rate of fire heat and helps to prevent the collapse of structures and human losses.The vital design factors are decided in the detailed design stage.The determined design thickness must be accurately applied in the fabrication yard.However,there are many cases that the PFP is overused because of various reasons.This excessive application of the PFP is an unavoidable problem.Several studies have been conducted on the efficient application and optimal design of the PFP.However,the strength of the PFP has not been considered.In addition,research studies on the correlation between the thickness of the PFP and the structural behaviour are not widely available.Therefore,this study attempts to analyse the thermal and mechanical effects of the PFP on the structure when it is applied to the structural member.In particular,it is intended to determine the change in the behaviour of the structural member as the thickness of the PFP increases.

Exploration of Protection of Traditional Ancient Villages: A Case Study of Qinglinkou in Erlangmiao Town, Jiangyou City

In recent years, ancient villages in China have attracted widespread attention from domestic and foreign experts and scholars. The people began to understand the important art, history, scientific value and profound cultural connotation of traditional architecture, and the importance of protecting ancient vil ages has become increasingly prominent. Taking Qinglinkou in Erlangmiao Town, Jiangyou City as a case, the methods and contents for the protection of ancient villages were studied, and the key elements of conservation and priorities of planning and protection of ancient villages were explored, with a view to providing experience for the current protection of ancient villages.

Empirical Research on Factors Influencing Level of Environmental Protection Information Disclosure in Annual Reportsby Listed Companies

Taking 248 A-share manufacturing listed companies in 2006 Shanghai Stock Exchange as example, using "index method" to measure level of environmental protection infor-mation disclosure, this paper examines the factors influencing level of environmental protection information disclosure. The findings show that the disclosure level has improved, but the overall level is still low and unable to satisfy information users; there is positive correlation between corporate size, industry type, accounting firm's type and corporate environmental dis-closure index. The companies of large scale and heavy pollu-tion and those audited by international "Big 4" and domestic "Big 10" accounting firms have a high level of environmental disclosure, while the profitability and financial leverage has no impact on the disclosure level. Finally some suggestions are put forward to establish environmental information disclosure sys-tem in China.