According to the demand on live-wire operation for Ningdong-Shandong ±660 kV DC transmission project, simulative calculation for human-body under live-wire operation is carried out. Therefore, the safety protection requirement and the main parameters of screening clothing are suggested. The research results could provide technical support for future live-sire operation on ±660 kV DC transmission line.
The composite foundation of belled pier and rock anchor is a new type tower foundation in transmission line engineering. The uplift test was carried out and the load-displacement characteristic was monitored. Based on the test data, the foundation uplift load bearing characteristic and failure pattern were analyzed. The calculation methodology on ultimate uplift capacity of composite foundation was proposed and was also verified by the field test results. The research result could give reference to future similar design and application.
The installed wind power capacity in China reaches to 44.733 GW at the end of 2010. Some potential wind power problems occur with the fast development of wind power. In 2011, wind farms consequently disconnected from the local power grid and severely impact the security of power grid. This paper investigates the large-scale wind farm disconnection accidents which happened recently in northwest China. The reasons that cause the accidents are analyzed. The characteristics of wind turbine generator made in China are compared with those made in other countries. The advices of developing wind power are proposed in this paper.
In recent years, micro-power wireless ad-hoc network technology is a kind of bidirectional wireless communications technology for automatic and wireless control. It has features of close quarters, low power consumption, low data rate, low complexity, low cost, and of great capacity, short delay, safety and reliability of the network. The paper introduces the principles and key technologies of micro-power wireless AMR(automatic meter reading) system. A wireless AMR system based on micro-power wireless technology and RS 485 communication standard is designed, of which the corresponding software is programmed to realize the wireless transmission and automatic meter reading. The system designed has low cost, high networking speed, high reliability and good extensibility. Application shows the system designed is successful and effective.
The information management system for flue gas emission in North China Grid mainly gathers and analyzes the data on pollutants of power plants within jurisdiction. Therefore, the substations of data acquisition system should be constructed for the power plants. For meeting the demand of secondary development, a multifunctional communication platform with wide application prospects is designed, which supports the external communications with other substations, and is independent on hardware environment of power plants. In addition, the platform is convenient to integrate the third party applications, simultaneously communicates with the third party nodes, and is advantageous in remote technical support and management service with different place by building and optimizing the support network for communication. Furthermore, the self-developed software installed ensures stable operation of the platform, and modular design guarantees good expansibility and easy portability. The platform developed is highly reliable and can work in harsh environment for a long time.
According to the centralized access of electrified railway to 220 kV substation of power grid in Turpan of Xinjiang, the access point voltage fluctuation is simulated when electric locomotive enters, of which the countermeasures are simulated and verified, providing references for the power departments to solve similar problems.
In this paper, the state equation of horizontal double bundle flexible conductor during short-circuit is deduced through analyzing the whole span of the conductor. Furthermore, the short-circuit tension and deformation of the conductor are calculated by solving the state equation. Finally, examples are given to verify that the method presented in this paper is more reasonable than the conventional ones.
Based on smart grid, the information flow of distribution network and the intelligent information technology are analysed. Based on the multi-agent, information hierarchies of distribution network are unified and various sub-resources of distribution network are integrated relying on the network technical architecture of Web Services. The architecture of a multi-centre information system of distribution network is established and the functions of the centres are introduced. The intelligent information system provides a workable solution to the building of distribution network.
A “two steps measures” for series power quality regulator(SPQR) in its limitation voltage is proposed based on the analysis of the pre-sag voltage compensation strategy’s optimal compensation aim. The proposed measures can make the equipment realize the optimal compensation aim with its fullest ability. The analysis formula and influence curves of optimal compensation aim show that the equipment’s optimal aim is influenced by three factors which include the limitation value of the compensation voltage, magnitude and phase of the source voltage. In addition, the source voltage variation scope which can realize the optimal compensation aim in limitation voltage is given. The analysis results will be useful to compensation strategy design and engineering practice.
The separate suspension angle tower applies the suspension insulator string instead of the strain insulator string. When the angle is bigger, the composition of the front and behind wire strain of tower along the internal angle direction pulls the insulator to enough angle, for meeting the electric clearance. The tower hangs the wire through separate tower, cancels the conductor cross-arm, improves the pulled condition of the tower, and reduces the tower torque of vertical load from the conductor and the overhead ground wire. Meanwhile, the tower removes the jumper insulator, reduces the number of the insulator, and simplifies the tower head clearance, convenient for the construction and maintenance. The separate suspension angle tower is a new type one, and can’t completely replace the strain angle tower due to lacking construction and operation experience, so that it is suggested to alternatively use the new tower and the strain angle tower, in order to extend the section length and save the project cost, as well as gain experience for the future application.
According to the first application of guyed V tower in 750 kV transmission lines, the selection, designs, construction and economic analysis of the tower are introduced in this paper. It is shown that the practical application of the tower can reduce investment, facilitate construction, reduce the environment influence, so that the economic and environmental effectiveness is significant.
The main electrical connection is very important for the design of substations. Several special problems are analyzed and discussed in designing the 3/2 breakers connection and high voltage shunt reactor circuits. These problems include the installation of disconnectors when two complete serials are formed, the retaining of key transmission channels when two buses are cut in the 3/2 breakers connection, and the disconnector and grounding switches in high voltage shunt reactor circuits. Some suggestions with certain reference value for substation designers are proposed.
Water Resources and Hydropower Research，Beijing 100038, China） In the cold district of north China， plume usually appears around the outlet of mechanical-draft cooling tower, which would impact on surrounding environment. In this paper we study the formation mechanism and the prevention method of the plume around mechanical-draft cooling tower. It was found that the using of dry-wet joint cooling towers is one of the effective measures to eliminate the plume.
According to the features of 660 MW ultra super-critical units and the manufacturing situation of domestic feedwater pump, the advantages, disadvantages and the problems of three schemes are analyzed for 100% or 2x50% capacity turbine-driven and 100% capacity main steam turbine driven feedwater pump. By analyzing the technical and economic factors of three schemes, it is found that the scheme of 100% capacity host-driven pump is optimal, providing references for similar units design.
The experimental study is carried out for the flow channel of a large-scale circulation pump, the flow pattern, water velocity and flow rotating strength is focused on. It is found that there exists a strong vortex in the lower part of the absorbing well and a spiral flow in the suction pipe, which could be the primary cause to affect the inlet of pump. The safety and reliability measures for the pump is thereafter suggested, the breast wall is used in the water-absorbing room, the elevation of the breast wall is optimized and given.
The primary sensitive factor that the thermal power units consider in four pipes design is the resistance by using bend or elbow. The divergence existing in resistance calculation of bend and elbow is clarified according to the U.S.Crane Co. manual which is the source of disputation and perplexity. It is demonstrated by comparisons that energy saving and resistance reducing are very obvious and the project cost is reduced by replacing elbow with bend, worthy of popularization in four pipes design. It is also shown from the access rules of resistance coefficient based on the Crane regulations that energy saving and resistance reducing exist theoretically in designing four pipes.
Coal breaker room, the largest and most complicated transfer station, is the difficulty for the design and layout of coal handling system in thermal power plant. However, the layout schemes of roller screen and coal breaker are the key point in designing the structure of coal breaker room, for avoiding the waste of space and increase of investment costs. According to the building area, storey height design and investment costs of coal breaker room, the parallel and stagger layout of roller screen and coal breaker are compared. It is found that the stagger layout is optimal.
The simulative calculation of a transient stability is performed by an electrical transient analysis program(ETAP) for a 2×660 MW coal fired power plant. Several conditions including fault and operation which may cause a big influence on the auxiliary power system of power plant are studied. The transient process is shown clearly by simulated waveform. The results give a strong support to the electrical system design of power plant.
Combined with the design rules of Indian CEA and Chinese design standards, a 300 MW power station in India is taken as an example, to compare the main steam-water system and lectotype design of key equipments in Indian and Chinese thermal power engineering. The design features and design basis are summarized of Indian thermal power engineering, providing references for similar contract negotiation and detailed units design of Indian thermal power engineering.
In tension stringing of overhead transmission line, stringing by helicopter will be feasible and much less expensive rather than traditional ways for some special terrain with high mountain and valley. Therefore, the helicopter tackle for tension stringing is developed, of which the innovative technologies include the design of leading string guide arm, eccentric rotary gate, centring valve, walking beam of anti-skidding truck and etc.
Fracture of primary materials in transmission tower is analyzed, main conclusions of material failure are drawn and suggestions for improvement is put forward by analyzing bearing capacity, chemical properties, low-temperature tensile properties, fracture part of main material and microstructure of the main fracture material. The results show that main reason for material failure is low-temperature brittle fracture which is mainly caused by cracks in the process of punching.
Based on analyzing the deformation characteristics of hot forming pipe fittings with A335P92 steel, the hot forming process of A335P92 steel is proposed, which is proved to be feasible by tests and inspection of products. It is shown for the hot forming process of A335P92 steel by tests that the heating temperature is 950~1 100 ℃, the heating preservation time is 1~2 h. In addition, some defects such as flaws will not occur after hot forming between 650 ℃ and 1 100 ℃ even though by water quench, and free cooling is permitted.
At the initial stage of electric power engineering construction, quick and accurate establishment of measurement area control system matching with national coordinate system is the chief task of electric power engineering measurement. The advanced precise point positioning(PPP) of global positioning system(GPS) is proposed, of which the positioning principles are analyzed. The technical and economic comparisons are carried out with other positioning methods. The reliability of PPP is proved by test analysis and the application method is presented. It is shown that PPP has the advantages of flexibility of traditional point positioning method and high precision of relative positioning one. In addition, it can easily solve the initial coordinate problem of first stage control in electric power engineering measurement. Thus, the hard work to find national level control points can be avoided. Particularly under such special conditions of post-disaster reconstruction, the advantage of PPP is prominent.
For the convenience of understanding and performing the codes, the technical background for canceling carbides and creep voids check of alloy steel, and for unenforced creep strain check of steam pipe at high temperature are emphatically introduced. The technical basis for control the hardness of 9%~12%Cr steel used in high temperature assemblies is analyzed. Furthermore, the revise of some important technical terms is demonstrated.
For single-phase grounding on the load side of 380 V PC bus in a 1 000 MW unit of power plant, burnout accident of potential transformer(PT) occurs. It is found after a detailed analysis of the accident that the grounding ways of LV auxiliary power system are different for 1 000 MW, and 600 MW or 300 MW unit, where the former applies small current grounding system via resistance grounding, while the latter generally adopts large current system via direct grounding. Therefore, the PT burnout accident is caused by improper selection of equipment, and equipment selection of large capacity unit should depend on actual situation.
In the expansion project of the UHV AC demonstration project, the installation of flexible busbar has great difficulty, which has the characteristics of large span, many spanned objects and big wire section. Therefore, two kinds of construction schemes are provided, including single-wire stringing and four-wire simultaneous stringing. According to technical argumentation, four-wire simultaneous stringing is optimal, of which the site operation is safety and successful.
According to the topographical condition of Yangtze River large-crossing at Heiyanzi, two tension stringing styles of anti-twisting steel wire ropes with □15mm are adopted to cross Yangzi River by reasonably arranging tension field and pulling field. Pulling ropes are connected flexibly at strain tower according to the demands, and loop string of ropes in pulley wheels is applied to reduce transportation between tension field and pulling field, which are different from traditional ways and could raise working efficiency.
Pipe explosion and leakage often occur in the heating surfaces of boiler in 1 000 MW unit. Taking the second phase project of Xinmi power plant in Henan as an example, the dependence of installation elevation error of the tower boiler on the installation quality of heating surface is analyzed. Based on the characteristics of boiler installation and the reasons resulting in elevation error, control measures of the installation elevation of the heating surface are proposed, which is proved well by practical application.
