Distribution Equipment Research Articles

Investigation of Defect Formation Process in Transmission and Distribution Equipment

The results of the statistical investigation of defect formation process in the equipment of electric networks are shown. Probabilistic characteristics of the stochastic process of the growing defects formation are determined for the 6/0.4 kV transformers with a high degree of confidence. The results will be used in the evaluation models of the equipment reliability under the actual maintenance condition.

The Pricing model for Transmission and Distribution Tariff Under Different Voltage Levels Based on the Long-run Marginal Cost Method

An incremental load model during peak load period in which both load rate and simultaneity of load is given. To mitigate the influence of irregular putting into operation of transmission and distribution equipment on fluctuation of marginal cost of transmission and distribution, an annuity calculation method of average incremental cost is proposed, and a calculation model based on long-term marginal cost, which can rationally share the expense of voltage classes, is built. According to incremental load during peak load period and the final average incremental cost to be borne by different voltage classes, the transmission and distribution prices for different voltage classes are calculated. Case study on longterm marginal cost of a certain regional power network is carried out, and calculation results show that the proposed transmission and distribution pricing method can reflect economic trend in the future and is favorable to eliminate crosssubsidies as well as make the electricity prices borne by various consumers in different voltage classes more fair and reasonable.

Power Quality Issues and Solutions – Review

Abstract Electrical power quality has been an important and growing problem because of the proliferation of nonlinear loads such as power electronic converters in typical power distribution systems in recent years. Particularly, voltage harmonics and power distribution equipment problems result from current harmonics produced by nonlinear loads. The Electronic equipment like, computers, battery chargers, electronic ballasts, variable frequency drives, and switch mode power supplies, generate perilous harmonics and cause enormous economic loss every year. Problems caused by power quality have great adverse economic impact on the utilities and customers. Due to that both power suppliers and power consumers are concerned about the power quality problems and compensation techniques. Power quality has become more and more serious with each passing day. As a result active power filter gains much more attention due to excellent harmonic and reactive power compensation in two-wire (single phase), three-wire (three-phase without neutral), and four-wire (three-phase with neutral) ac power networks with nonlinear loads. However, this is still a technology under development, and many new contributions and new control topologies have been reported in the last few years. It is aimed at providing a broad perspective on the status of APF technology to the researchers and application engineers dealing with power quality issues.

Sensitivity Analysis for Estimating Salt‐Induced Damage to Voltage–Current Transformers due to Typhoons

SUMMARYThe purpose of this paper is to analyze the correlation relationship between the salt contamination environment and the actual damage to electric power distribution equipment caused by two typhoons, 2012 typhoon No. 4 (T1204) and 2011 typhoon No. 15 (T1115). T1204 caused salt contamination damage to voltage–current transformers (VCTs), while the T1115 caused no damage to VCTs installed in a same target area. In this paper, the salt contamination environment during the two typhoons, which includes the maximum wind speed, the accumulated rainfall, and the Na flux, is evaluated by a weather reproduction simulation to discuss the causal relationship between the salt contamination environment and the VCT damage. A damage evaluation model is proposed to evaluate the salt‐induced damage risk potential of the VCT for reasonable restoration activity.

English

As a result of the nature of pollutant and exhaustible of fossils energies, developed countries have made use of renewable energy sources to make effective their energy systems. To stow on that vision in Cameroon, the promotion of micro-hydroelectric powers plants (MHPP) is a priority and any contribution to its ease is beneficial. The objective of this study is to characterize some main forges in the west region of Cameroon and show their technical input in the development of MHPP in that region. The survey was conducted in January, 2014. Socioeconomic data related to blacksmiths and main features were studied by the use of questionnaires, direct interviews, site observations and measurements. Main results show that the first forges was set in the Foto village in 1850 by blacksmiths from Nigeria. The studied forges are of traditional (62.5%) and modern type (37.5%). More than 50 products belonging to the main use sectors are manufactured, adapted and/or repaired. The main problems identified are acquisition of raw materials, the lack of equipment and limited technical knowledge. The blacksmiths has been involved in MHPP facilities since 1997, the installation year of the pilot MHPP with the participation of local craftsmen. Civil engineering structures, hydroelectric unit, transportation and distribution equipment are built by local blacksmiths using as much maximum materials as possible. This is often a source of malfunction. Thus, funding of local craftsman and equipment by the government or other agencies can render the forges useful for sustainable development in the west region of Cameroon.   Key words: Study, blacksmiths, micro hydroelectricity, funding, Cameroon.

Voltage Measurement Accuracy Assessment System for Distribution Equipment of Smart Distribution Network

A new system for evaluating the voltage management errors of distribution equipment is presented in this paper. The main concept of the new system is to use real distribution live-line voltage to evaluate and correct the voltage measurement data from distribution equipment. This new approach is suitable for a new Distribution Management System (DMS) which has been developed for a distribution power system due to the connection of distributed generation growth. The data from distribution equipment that is installed at distribution lines must be accurate for the performance of the DMS. The proposed system is expected to provide a solution for voltage measurement accuracy assessment for the reliable and efficient operation of the DMS. An experimental study on actual distribution equipment verifies that this voltage measurement accuracy assessment system can assess and calibrate the voltage measurement data from distribution equipment installed at the distribution line.

Rebuilding After a Disaster: Turning a Bad Situation into an Opportunity to Make Electrical Safety Improvements

In February 2011, construction had just begun on a planned electrical safety improvement project at the East Bay Municipal Utility District's (EBMUD's) Walnut Creek raw water pumping plants (WCPPs 1 and 2) when the electrical substation powering the facility was destroyed by a fault. This was followed a month later by a flood that completely filled the building that houses WCPPs 1 and 2, submerging six large synchronous motors, pumps, and related electrical distribution equipment. These nearly simultaneous catastrophic events dramatically expanded and redefined the scope of the planned work. An immediate priority was to rebuild the electrical substation within 12 months so that the district could restore power to the undamaged WCPP 3 to meet the anticipated summer pumping demands. A longer-term priority was to completely rebuild the pumps and motors and replace the station service motor control centers (MCCs); switchgear lineups; controls; and the heating, ventilation, and air conditioning system at WCPPs 1 and 2 within the next 24 months. This article presents how these two incidents occurred and discusses how they were turned into an enhanced safety design opportunity.

EFFICIENCY RISE OF GAS LEAKAGE CONTROL THROUH FAILURE CONNECTIONS OF GAS DISTRIBUTION AND GAS CONSUMPTION NETWORK EQUIPMENT

Generation of gas leakages through failure connections is inevitable at operation of gas distribution and gas consumption network equipment. Natural gas refers to the greenhouse gases. Methane, penetrating into atmosphere, is concentrated above the surface of the Earth. It brings temperature increasing to environment. Detection of gas leakage place and numerical definition of the leakage size is the actual task even because it influences the establish standard of technological gas losses detection while it is conveying through gas distribution and gas consumption networks and finally on the tariff forming at calculations for gas. Gas analyzers and gas meters are used traditionally for the leakage size determining. The process of the leakage size numerical definition, using a gas meter is laborious as it is connected with setting hermetical cover of definite volume that closes the whole object of leakage and subsequent filling of the volume by natural gas. The numerical definition method of leakage size with the help of laser methane detector has been developed with the aim of laboriousness lowering of defining the leakage size. It has been given the results of experimental defining for different intensity leakage volume by natural gas meter and by laser methane detector according to methane concentration in a gas cloud at different gas pressure values in a gas pipeline and different orientation of leakage source relative to gas pipeline. Analytic dependencies for calculation of natural gas loss quantity through non sealed nodes according to excess gas pressure in a gas pipeline and methane concentration in the region of leakage taking into account orientation of gas cloud in space have been established. It has been defined experimentally that definition error of gas loss by laser methane detector not more than 10%.

受配電機器絶縁物の経年劣化に影響する要因

受配電機器絶縁物の経年劣化に影響する要因

The Current Research on Distribution Automation System

A distribution system consists of all sorts of power distribution equipment, communication system and control equipment. It works according to certain rules to meet the demand of users by the high quality of electric energy. Distribution Automation(DA) can realize the automation of system operation and management to provide customers with stable, reliable electricity and obtain maximum benefits .This paper generally introduces the concept, function, developing future of Distribution Automation System. Distribution Automation includes feeder automation, automatic distribution management and user automation, and this paper introduces the basic situation and problems of them. Finally, it is concluded that Distribution Automation is the inevitable trend of Distribution System，and will be gradually developing in the direction of smart distribution grid.

IEC 62110に準拠した配電用機器から発生する磁界の評価

IEC 62110に準拠した配電用機器から発生する磁界の評価

Adaptation Evaluation Method of Distribution Network to Accept Distributed Generations

Adaptation evaluation index system is established according to the influences brought by the distributed generations (DGs) interconnected with the distribution network. Evaluation indicators are proposed to reflect the operating conditions of distribution lines, switches and other important devices of distribution network. Combine Analytic Hierarchy Process (AHP) and Principal Component Analysis (PCA) method is used to determine the weights of the evaluation indicators. Whereby obtain the comprehensive evaluation results of distribution equipment adaptation to DGs integration. A study of a practical grid is made in the cases of the DGs centralized integration, decentralized integration, and without DGs. The simulated result shows that a large number of DGs connected with the distribution network would deteriorate a majority of the equipment operating indicators, especially to the indexes related to switches and protection devices. Meanwhile, when a distribution network is connected into the same capacity of DGs, the distribution equipment would show a better adaptation to DGs' decentralized integration.

Application of Fault Location Method Based on Multi-Source Fault Information in Repair of Distribution Network

Fault location method based on multi-source fault information in repair of distribution network is proposed to make the precision and speed of fault location higher. Firstly a topology description and storage method which is appropriate to distribution network fault location is proposed. Then, based on the topological structure of distribution network, fault information on the distribution network is integrated processed. Fault information grouped and priorities are identified using the association of distribution equipment. Low-voltage fault location is achieved by applying fuzzy set theory in fault message omissions and misstatements situations. Finally, an example demonstrates the effectiveness of this method.

電気設備機器(受変電, 配電設備機器)

電気設備機器(受変電, 配電設備機器)

Understanding Infrared Windows and Their Effects on Infrared Readings

The use of infrared (IR) windows in electrical control and distribution equipment has become increasingly more prevalent over recent years. With increased focus on electrical safety and the widespread adoption by industry of NFPA-70E, IR systems are increasingly more popular. However, using IR windows with thermal imaging cameras introduces a serious problem when it comes to predictive maintenance, i.e., measurement accuracy. This paper discusses the effects of various materials used in IR windows for noncontact temperature measurement. Varying degrees of measurement inaccuracy and methods to correct for these inaccuracies with various thermal imagers is covered. Other factors outlined will include the factors affecting IR transmission through various IR window materials used in various practical electrical inspection applications. Moreover, how these various materials affect the accuracy of the readings and ways to correct these various transmission losses will be also addressed. The conclusions provide the details for a successful preventive and predictive maintenance program when using various thermal imagers along with different types of IR windows.

Reducing the Fault Current and Overvoltage in a Distribution System With Distributed Generation Units Through an Active Type SFCL

For a power distribution system with distributed generation (DG) units, its fault current and induced overvoltage under abnormal conditions should be taken into account seriously. In consideration that applying superconducting fault current limiter (SFCL) may be a feasible solution, in this paper, the effects of a voltage compensation type active SFCL on them are studied through theoretical derivation and simulation. The active SFCL is composed of an air-core superconducting transformer and a PWM converter. The magnetic field in the air-core can be controlled by adjusting the converters output current, and then the active SFCLs equivalent impedance can be regulated for current-limitation and possible overvoltage suppression. During the study process, in view of the changes in the locations of the DG units connected to the system, the DG units injection capacities and the fault positions, the active SFCLs current-limiting and overvoltage-suppressing characteristics are both simulated in MATLAB. The simulation results show that the active SFCL can play an obvious role in restraining the fault current and overvoltage, and it can contribute to avoiding damage on the relevant distribution equipment and improve the systems safety and reliability.

Overview of Distribution Automation

A distribution system consists of all sorts of power distribution equipment, communication system and control equipment. It works according to certain rules to meet the demand of users by the high quality of electric energy . Distribution Automation (DA) can realize the automation of system operation and management to provide customers with stable, reliable electricity and obtain maximum benefits .This paper generally introduces the concept, function, developing future of Distribution Automation System. Distribution Automation includes feeder automation, automatic distribution management and user automation, and this paper introduces the basic situation and problems of them. Finally, it is concluded that Distribution Automation is the inevitable trend of Distribution System,and will be gradually developing in the direction of smart distribution grid.

Numerical Analysis and Performance Test of Interactive Platform Based on Multi-Media Internet Architecture

Streaming media technology is also known as streaming media technology. Users can experience playing while downloading function, which improves the transmission speed of multimedia information on the internet. In this paper, we use streaming media technology, combined with the parabolic interpolation and Newton interpolation algorithm, design multimedia interactive platform of the college students' ideological and political education and comprehensive education. The overall structure of the platform is composed of multimedia, streaming media distribution equipment, school network, clients of teachers and students. On the internet between the teachers and students, student and students they can communicate ideological and political. In order to test the performance of network, we use the iperf software to test packet loss rate and delay characteristics of the network. The results show that Newton interpolation method has better delay characteristics, parabolic interpolation algorithm has low packet loss rate. It provides technical reference for the application of multimedia technology in the ideological and political education.

Design and Realization of Monitoring System for Offshore Platform Transformation and Distribution Equipment Based on OPC Technology

Monitoring system for transformation and distribution equipments plays an important role in offshore platform safety production. This paper introduces the OPC technology and discusses the requirements and architecture of this monitoring system. For the convenience of monitoring data exchange, OPC technology is applied in the design and realization of the monitoring system. An OPC server is created for the monitoring data publication, and the monitoring system can get cable load current data from the OPC server in the central control system. In this way,the monitoring system can exchange monitoring data with the central control system more efficiently.

Design and Realization of Monitoring System for Offshore Platform Transformation and Distribution Equipment Based on OPC Technology

Design and Realization of Monitoring System for Offshore Platform Transformation and Distribution Equipment Based on OPC Technology