电力行业95598综合信息系统研究与设计

介绍了电力行业95598综合信息系统的重要性、意义以及设计原则,分析系统业务功能并设计出电力行业95598综合信息系统体系架构。     

Measurement of handle forces for crimping connectors and cutting cable in the electric power industry

Overhead and underground line work in the electric power industry is physically very strenuous and can expose workers to musculoskeletal disorders (MSDs), particularly in the upper extremity. Crimping compression connectors—such as sleeve connectors and lugs—and cutting cables are two of the most frequent tasks that line workers perform. Line workers at many utilities in the US crimp connectors and cut cable with long-handled manual tools. However, the actual magnitude of the forces applied to the handles of these tools is not known. The objectives of this laboratory study were to measure the forces applied to the handles of a manual press and a manual cutter in order to connect typical wire gauges and cut common cables, respectively. The handles of the manual press and cutter were attached to the drive cylinder and load cell of an Instrom Material Testing System, and peak forces exerted against the handles were measured. Results showed that the outer die of the manual press required about 50% more handle force than crimping connectors with the inner die location. The peak handle forces required to cut aluminum conductor cable as large as 2 cm diameter exceeded 500 N and were about 200 N greater than the peak forces to compress connectors manually. When the peak force data were compared to strength capabilities reported in the literature, less than 1% of the general population was found to have the maximum strength to manually make one crimp on a common overhead connector. Less than 1% and approximately 50% of the female and male general population, respectively, were found to have the maximum strength to manually cut a cable with a 2 cm diameter conductor. Handle force data from this study provide a biomechanical framework for explaining how the job demands of overhead and underground line workers could possibly cause MSDs.

Relevance to industry

Electric power utilities can review their work practices and tools in order to determine whether they can reduce the exposure of their workers to risk factors of MSDs, as well as reduce their cost of health care. Manufacturers of crimping and cutting tools can use the experimental approach in this study to measure the external forces required for their respective tools and then set quantitative force benchmarks to improve the design of their tools.     

电力行业网络安全现状及解决方案探讨

随着科技的不断进步和发展,网络技术已经被广泛运用到电力行业中,其大大提高了电力行业的工作效率,但其网络安全问题也不容忽视。本文简要分析了电力行业计算机网络安全存在的主要风险,并从管理和技术两个方面提出了网络安全防护的解决方案。     

Optimal electric power load-dispatching

An electric power load-dispatching model was developed for Du Pont's Savannah River Plant. This model economically optimizes the distribution of load simultaneously supplied by power produced at each of the three area generation stations and the amount of power purchased from South Carolina Electric and Gas Company. An iterative, mixed-integer linear programming technique is used to find the “optimal” solution.     

Measures to prevent portable ladder accidents in the construction industry

Abstract

Ladder accidents account for nearly 5% of all reported occupational accidents in the Swedish construction industry. Eighty-five ladder accident victims were interviewed to obtain detailed information about factors contributing to their accidents. Accidents were almost equally divided between straight ladders (N = 39) and step- ladder (N = 33). The majority of accidents occurred while the victim was working from the ladder. Climbing up and, particularly, down straight ladders was associated with numerous accidents. For straight ladders, sliding at the base was the most common event preceding the injury. Low angle of inclination was a common contributing factor. For step-ladders, tipping sideways was the most common preceding event. Misstepping the final step while descending accounted for 10% of all accidents. More than 90% of the victims fell from less than 4 m. The interviews provided detailed information which served as a basis for proposals for alternatives to portable ladders; a step-scaffold adjustable for work at levels up to 3 m and a portable scaffold for work at levels of 1–3 m. These alternatives are under development. In addition, proposals for improving the stability of current portable ladders are made.     

Comparisons of variables between fatal and nonfatal accidents in manufacturing industry

This study concerns with the comparisons of variables between fatal and nonfatal accidents in Korean manufacturing industries. The national industrial accident statistics for the years 1991–1994 were extracted from the annual publications of Ministry of Labor. These data were used to compare the distributions of fatal and nonfatal injuries in terms of company size, injured person's age, work experience, accident time, activity at time of accident, accident type, injury type, injured body part, and accident agency. Results show that the distributions of the fatal injuries are statistically different from those of the nonfatal injuries: (1) nonfatal injuries occur more frequently in the younger workers, while deaths occur more frequently in the older workers; (2) the proportion of death occurring in night shift is greater than that of nonfatal injuries; (3) `caught in and between objects' is the most common type of accident, but the second common type of accident is `awkward or sudden movement' in the nonfatal injuries, instead of `falls from a height' in deaths; and (4) `fracture' is the leading caused injury and death, but the second leading type of injury is `contusion or bruise' in the nonfatal injuries and `cerebral concussion' in deaths.

Relevance to industry

Strategies for accident prevention should be in reasonable agreement with significant variables of occupational accidents. These results can be used to develop more effective accidental occupational death and injury prevention programs for manufacturing industry.     

Identification of load pockets and market power in electric power systems

In this paper, we present a spectral method for the identification of load pockets and the application of practical techniques for the measurement of market power. Market power is a serious concern in electric energy markets, especially in the area of a load pocket. Common definitions for market power, which rely on a comparison between market prices and a so-called competitive price, are difficult to use in practice because the competitive price is not known when the market is not competitive. The competitive price cannot be computed from data naturally available to the market. Our technique focuses on the identification of participants with the ability to increase revenues by increasing prices, an ability not present in a competitive market. We then propose measures for quantifying the extent to which market power is being exercised. These measures can be computed from data available to the market; they are practical. We present results from a 30 bus, 6 generator system, which illustrates that generators in a load pocket have and can exploit joint market power.     

Reasoning and knowledge of nuclear power plant operators in case of accidents

This paper presents the results of an ergonomics analysis of the work activities of nuclear power plant operators. It focuses on cognitive activity during simulated accidents. Qualitative aspects of this activity are described, which include operators' knowledge, diagnoses, goals, situation ranking and procedure management. The results show that successful emergency operation depends on a combination of adherence to procedures and specific operator competence.     

The quadratic eigenvalue problem in electric power systems

The application of the quadratic eigenvalue problem in electrical power systems is reviewed. The spectrum and pseudospectrum of an electrical power system are defined.     

Modern problems of electric power systems reliability

We briefly characterize certain reliability problems for power engineering systems relevant at present, on the liberalized power market. We show a reliability problem setting for these conditions and its implementation in a computational complex.     

Systems modelling of the electric power objects

In order to carry out the complex researches of the influence of the different factors on the object-system operation efficiency in the electric power system (EPS), the multi-level systems models which represent the connections and relations between the elements of an object modelled are required.As an example of the systems approach to the modelling of the EPS one may consider the experience of developing the set of the model and program modules united into the system which describes the electromagnetic and heat processes in the turbogenerators; the characteristics of the assemblies connected to the electric power station, the static & dynamic operation conditions of the EPS and the distribution of the active & reactive power in the EPS units. The program modules are united by the common data base. The control programs provide for the systems analysis of a problem in question in the dialogue man-machine mode of operation.     

Decentralized stabilization of large electric power systems

This paper considers the problem of stabilizing the dynamics of a large electric power system, represented by a linear time invariant system of equations, by using several decentralized (or local) state feedback control laws. The stabilization problem is formulated into a functional minimization problem which implicitly controls the closed-loop eigenvalues of the controlled system. The constraint of decentralization is tackled in the minimization algorithm by using the method of feasible directions. To illustrate the application of the algorithm, it is used to stabilize a three machine electric power system.     

Some new results of electric power science

At present, one of the most important demands in the world is energy. And improvement of technology and management can increase energy efficiency [1]. Compared with     

Large scale control problems in electric power systems

The main large-scale control problems in electric power system operation, from optimal allocation of generation and transmission resources to network state estimation, frequency and exchange power control, system stability and dynamic security, are illustrated and the methods presently used to solve them are recalled. Special attention is given to significant applications of decomposition by physical decoupling and relaxation or by time-division of decentralized controls, of coordination and hierarchies, with a brief mention of large system analysis areas open to further development.     

基于DSP的任意波形PWM调制技术

本文阐述了一种任意波形PWM调制的方法,并且应用于有源滤波器的控制电路.实验装置采用高速的数字信号处理器TMS320LF2407A为核心器件,可以快速完成整个控制方案.从实验结果来看,有源滤波器系统能够有效的消除由非线性负载产生的谐波,大大降低了谐波对电网造成的危害.     

Optimal control of generator resynchronisation in electric power systems

Optimal control techniques are discussed for the resynchronisation of a steam turbine unit in an electric power system after it has lost synchronism. A time optimal control is derived and the resulting bang-bang control law is first simulated on an analogue computer and then implemented on a physical generator in a model power system. Aspects of implementation on a full scale power system are discussed, and the proposed controller is shown to be quite general and applicable to all turbine generators and systems.     

软件同步采样技术在电能计量中应用

根据电能计量的实际需要,分析了采用软件实现同步交流采样的工作原理。结合DSP技术给出一种基于TMS320LF2407a芯片和MAX125的软件同步采样处理系统的硬件实现方案及软件设计思想,可减少硬件的复杂度的同时保证检测精度。最后,讨论了系统抗干扰设计。     

DSP技术在电力参数测量中的应用

提出了利用DSP技术测量电力参数的基本思想，对相住误差引起的电力参数中的有功功率和无功功率误差进行了补偿。给出了详细的硬件电路和软件设计。最后对系统应用中的测量精度进行了分析。     

电力通信网络中负载均衡的路由协议

在电力通信网络中,负载均衡能够减少瓶颈节点的过载情况,有助于提升电力通信系统的可靠性和网络资源利用率。针对电力通信网络独特的结构与流量特征,提出一种确定性路由与机会路由相结合的负载均衡的路由协议。每个节点从以自己为中心的区域中选出候选节点集合负责转发数据包,候选节点依据局部的准确代价与远处的估计代价划分优先级并决定转发概率。与负载均衡优先的开放最短路径优先（LBA-OSPF）协议相比,节点平均负载降低了32.3%,端到端时延减少了50.3%。     

Decision theory for fault diagnosis in electric power systems

In state estimation of electric power systems, anomalous measurement diagnosis is essential for guaranteeing a reliable database. More specifically, the identification of anomalous data is a very important but also very difficult task, especially in the case of multiple interacting ones. This work focuses primarily on the latter problem. The proposed solution is based on the classical hypothesis testing of decision theory and its application to the random vector of measurement error estimates; the latter are obtained via a perfect observations estimator which is proven to be optimal. Further, strategies able to treat any type of bad measurements are considered; the identification strategy under an upper bounded β risk is chosen and extensively exploited. The developments concern reliability aspects as well as on-line computational requirements for which many algorithmic improvements and useful formulae are derived. A practical example, coming from actual implementation experience, illustrates the overall methodology and shows the consistently good performances of the method.