Abstract:Communication network plays a crucial role in the development of a first-class power distribution network. This paper introduced in details the principles of Ethernet passive optical network (EPON) and industrial Ethernet technology, and then analyzed EPON network scheme and industrial Ethernet network schemes. By comparing the two network technologies, this paper highlighted the characters and deficiency of the two network schemes if they are used in individual. Based on the comparison, a new hybrid communication network scheme for distribution networks based on EPON and industrial Ethernet is proposed. The scheme has better performances in terms of reliability, extensibility, access convenience, compatibility and ability to adapt to the practical situations. At last, an example of the engineering practice of the proposed network scheme in Suzhou Power Supply Company is introduced.

Abstract:In order to improve the safety, stability, and operational economy of the forced draft fans, performance tests were performed in the 600 MW power unit of Ningdong Power Generation Company. Based on the acquired test data, two retrofit schemes were proposed for the draft fans, including frequency conversion and operation at lower speed. According to the contrast results, the latter scheme was adopted finally. The test results after retrofitting showed that the efficiency of forced draft fans had been greatly improved, and very satisfactory energy-saving results were achieved.

Abstract:A secondary voltage abnormal rising fault of 35 kV capacitor voltage transformer is introduced. This fault is caused by short-circuit of primary coil in the electromagnetic unit. Some feasible measures are proposed to detect potential faults and to take precautions against accident by online monitoring and infrared accurate thermometry.

Abstract:After the maintenance of backup high-voltage transformer in Tianwan nuclear power station, a three-phase voltage unbalance phenomenon on low voltage side potential transformer appeared. We analyzed this phenomenon by using nodal method, and found that the voltage unbalance is caused by load neutral displacement. After eliminating the load neutral displacement, three-phase voltage unbalance phenomenon still occurred on one potential transformer. A further detailed check is implemented and we found that the unbalance is caused by the fault of fuse base. After eliminated this defect, the three-phase voltage of the potential transformer becomes normal.

Abstract:A distribution network usually contains many various functional components. The implementation of distribution system automation needs to integrate information from all components. In IEC61970/61968 standard, the CIM and CIS are recommended. Based on the CIM and CIS, the splicing data from different components and the real-time interaction between data are studied in practical engineering. The result shows that the CIM and CIS benefit heterogeneity data exchange, lay out a foundation for heterogeneity data exchange, standard establishment and open architecture of distribution power grid, and can provide supports to establish "plug and play" smart distribution power grid.

Abstract:In order to tackle the difficulty in the test of backup power of supercapacitor of electric pitch system, we designed a simple and feasible test equipment for factory-inside backup power. With the test equipment, a test on a specific type of supercapacitor is implements. Based on the test, a design of backup power is provided. The design can meet the demand of feathering of pitch system, and guarantee the safe operation of wind turbine generator system.

Abstract:For satisfying the demand of fast clearing fault on Middle-low Busbar, an over-current block protection approach for is proposed. The typical short circuit faults on middle-low voltage busbar are analyzed. With the advantage of GOOSE networks in the substation, a novel-type middle-low voltage busbar protection is designed. The details of the process of protection design and handling communication interrupt are presented. The effectiveness and reliability of the proposed approach are validated by practical application in a smart substation.

Abstract:A new DC deicer system with 12-pulse mode and 5000 A rated current is developed. According to the parameters of AC transmission lines, some of its important aspects of PCS-9590 are introduced, including deicing solution, main circuit design, overvoltage and insulation coordination, control and protection system. Field application shows that the proposed DC deicer is an effective solution for the ice-clad problem of AC lines.

Abstract:Through standardize the sampling of data of safety equipment, power system secondary security monitoring can achieve real-time warning and operating status monitoring for the safety equipment, and detect the presence of various types of security system risks and abnormal access behavior. With the studying of log collection technology, a norm for power system secondary security log collection is formed. With the research of cascade communications between upper and lower dispatch monitor center, a hierarchical deployment of functions is achieved. Through studying the security state of D5000 host in dispatch center, the security monitoring on D5000 is achieved.

Abstract:Line protection of double circuit lines on the same tower are generally designed with only considering each independent single line. This kind of design scarifies protection's sensitivity for ensuring its reliability Based on the principle of independent configuration, the paper proposes an approach t is proposed to optimize the performance of protection for both double circuit lines with sharing the information of two lines through the station communication network. The proposed approach provides solutions for double loop cross line fault phase selection, analyzing the influence of zero sequence mutual inductance, fault distance measurement and distance protection.

Abstract:The new generation of busbar protection is realized on the unified and advanced UAPC platform, which is wit modular-designed hardware and software and convenient for update and maintenance. A new object- oriented interval busbar protection design method is utilized, which makes the configuration of differential section feasible. The synchronization distributed busbar protection devices is with a high-performance on reliability and time. Busbar protection status monitoring technology improves reliability and reduces maintenance personnel's workload.

Abstract:This paper presents a proposal for the implementation of graph and model integration software for smart substation. The software takes primary and secondary equipment as the configurable objects, provides plenty of user interfaces for configuration, and eventually implements a complete set of design works for smart substation. The functionalities of the software include drawing single line diagram, modeling equipment, physical connection and virtual connection, etc. Additionally, based on the AutoCAD-based development, the software organizes and analyses the configuration data and exports them in various AutoCAD drawings according to user requirements.

Abstract:A generic, configurable and high-performance device platform is developed for large capacity sampling of the smart substation digital device. This platform solves the sampling bottleneck problem by using PCIe bus as a special sampling channel, and greatly enhance the overall data exchange capability through the key technology of DMA and LVDS. Engineering application shows that the platform is effective and convenient in large capacity sampling and real-time data exchange.

Abstract:The productivity of electric distribution network repair is directly related to the reliability of power supply. In this paper, a mobile application system for electric distribution network rush repair is designed and realized. Based on mobile Internet technology, the system provides the service of sharing information between repairing workers and engineers in the master office which can overcome the shortcomings of traditional management systems. Application shows that the proposed system can increase repairing efficiency significantly and guarantee data accuracy.

Abstract:With the improvement of manufacturing of transmission and transformer equipment and the progress of on-line monitoring technology for power grid equipment, the model of equipment maintenance is changing from periodical maintenance to status decided maintenance. An evaluating approach and maintenance strategy for the power grid including equipment and circuit is proposed. The practice of the proposed strategy is validated by engineering projects. For the views of power system and customers, it benefits the cost management of power supply enterprise and the reliability of power supply.

Abstract:There are various testing items for the transformer in order to evaluate its performance. However, nowadays most of the test instrument could only measure one or two items. A comprehensive electrical test system is designed and realized in this paper, which integrated the conventional test items for the transformer including the insulation resistance, the short circuit impedance, transformer ratio, DC resistance of winding, dielectric loss, the transition resistance and transition time of on load tap changer of transformers and so on. The corresponding software is developed based on C# programming language. With the comprehensive electrical test system, a 'one-key operation' test for transformers is achieved, which improves testing efficiency largely.

Abstract:By analyzing the measuring principle of Rogowski coil, a new current transducer with the Rogowski coil is proposed for on-line measuring indoor power supply load currents. The Rogowski coil is designed with plastic ring and enamel-insulated copper wire, which are used as its framework and winding wire, respectively, and the signal processing circuit is designed with two precise operating amplifiers by employing OPA 211 with low noise. Amongst, the first amplifier serves to amplify the inducted millivolt signal form the Rogowski coil, while the second amplifier serves to restore the measured current signal and filter the yielded interrupt noise signal. The experiment results show that the proposed Rogowski coil and its signal processing circuit has merits of good linearity, high measuring precision and low manufacturing cost, which meets the measuring requirement of industry frequency current transducer with 0.5 grade and has important engineering application value.

Abstract:The tunnels of power underground are in the depth of more than 10 meters. In the area of soft soil foundation at the Yangtze River, they are often built in the soil layer. However, power transmission towers also constructed near the path of tunnels, which cannot be evaded. With practical engineering projects, analysis on the soil reinforcement are implemented in terms of reliability, economic and effectiveness. The research provide a reference for future similar construction projects.

Abstract:In this paper, based on the project of Jiangsu Huadian Jurong Power Plant, pipe modeling and static calculation of the main stream pipes are performed by respectively using Caesar Ⅱ and Glif. The results of the static calculation, including the cold and hot state displacement value, the joint thrust and torque at the pipe connections of the boiler and the steam turbine as well as the selection of the spring, are analyzed and compared. The results show that basically consistent results are achieved by Caesar Ⅱ and Glif, for the static analysis of high temperature and high pressure pipelines.

Abstract:In one 150 MW power unit newly put into operation, it was found that the water-vapour quality cannot meet the requirement. After analyzing the main reasons, we proposed several solution measures, which have been validated to be effective by the operation data acquired in two power units adopting them.

Abstract:The tube blowing mode not employing circulating pump is adopted in one 1000 MW ultra-supercritical boiler. The fundamentals of this blowing mode as well as the key points during the implementation process are introduced in this paper. Then, the typical faults encountered during practical application processes are analyzed, and the issues needing more attention are summarized. After thoroughly comparing the conventional and current methods, their main advantages are analyzed, which may provide valuable references for similar coal-fired power plants.

Abstract:Tube overheating issues were frequently observed during the start-up and normal operation periods of the ultra-supercritical boiler of Datang Lvsigang Power Generation Co. Ltd. The undesired high tube temperature can lead to higher steam-side oxidation rate, which has significant effect on the safety of the boiler. Through thoroughly analyzing the acquired start-up and operation parameters, we proposed in this paper several prevention measures.

Abstract:The most important indicator in the assessment of unit operation performance is coal consumption of electricity generation and supply, which largely depends on the accuracy of belt scales. In order to improve the accuracy of power station coal consumption management, this paper mainly analyze the factors that affect the accuracy of belt scale of the furnace-entering coal based on the coal handling system employed in one power plant. The method used to process the measurement data is presented and based on that a method for determining the accuracy of belt scale through calculation employing field data is proposed.

Abstract:Offshore wind farm is seen as the future development of wind power utilization trend and attracts more and more attention for its superiority such as abundant, stable, less interference and so on. Three grid connected program of offshore wind farm, HVAC, LCC-HVDC, and HVDC-Flexible are analyzed and compared with each other. Specific programs of HVDC flexible and AC-DC converter station topology for offshore wind farm are discussed.