Using commercial computation fluid dynanics （CFD）software fluent, and based on the k-ε equations and the renomalization group model, the flow field of the centrifugal induced draft fan was numerically simulated. Using the Lagrangian particle trajectory model, the running track of the solid particles in the fan was obtained; and the feasibility of reducing particle deposition with numerical simulation was verified by adding blowing air.
The planning and the optimization of biomass thermal power are directly related to the economic operation, biomass resource utilization and environmental protection. On the basis of establishing an index system for the evaluation of site selection for biomass thermal power plants, the rough set method was applied to obtain the index weights based on potential information of the system. Through decision-making of experts, the quantitative and qualitative information was integrated, and then the priority of the alternative locations was obtained. The multi-objective optimal model for the planning and optimization of the biomass thermal power plant was built up to balance the economical efficiency and the average comprehensive efficiency. In consideration of decision-maker’s predilection and heat load demand, the goals of cost minimization and average comprehensive efficiency maximization were achieved at the same time, and the plant scale and heating scheduling optimization scheme were obtained. The numeric example indicated that the method for the planning and optimization of the biomass thermal power plant is scientific and practical.
Based on an analysis on conductor selection and the current-carrying capacity calculation of overhead transmission lines, this paper presents the factors which determine the transmission capability, proposes the recommended values of the ultimate thermotolerant current-carrying capacity of common conductors for 220 kV and 500 kV overhead transmission lines and offers some proposals on improving the transmission capabilities of the Jiangsu grid.
Traditional transmission line imbalance tension calculation algorithm is studied and factors which affect traditional algorithm’s convergence are analyzed.A new imbalance tension calculation algorithm with mending steps is studied.And the methods of initial value selected and step mended are studied and the flow chart of the program is presented.Every span’s tension in one section segment under 11 kinds of operating conditions are calculated.The same result is obtained using 2 algorithm.But the efficiency of mending steps algorithm is improved greatly.
The glass fibre reinforced plastic(GFRP) gantry in the earth electrode of Jingmen converter station apply GFRP composite materials to gantry of switchyard first in our country. To understand laoding characters of GFRP gantry, and considering joint connection rationality. GFRP gantry is designed to perform mechanical property under preliminary load，design load，over loading ,and measure corresponding gantry displacements。Test results show that it is practicality、rationalty and safety to apply GFRP composite materials to gantry，and through optimizing cross-section size and length of GFRP pipe，which weight is reduce 33% than steel gantry。Test results offer the basis of theory and practice for the extended application of GFRP gantry.
One of most important things before the structural analysis is choosing the right calculation model. In order to find out the behavior of the transmission tower in different wind conditions, an angle steel tower and tube tower were analyzed with truss model, beam-truss model and rigid model. The results showed that using truss model can meet design specification in angle steel tower. However, the results indicated that it’s much more reasonable to use beam model than the truss model in tube tower.
ABSTRACT：Compared to the angle-steel tower, the steel tube tower is much larger in load, height and span. The node design is the key link to ensure the structural safety of steel tube towers. Based on a case study of the large steel tube tower for 1 000 kV UHV(ultra high voltage) lines, a finite element model of the typical K-Joint is established and the mechanical behavior, stress distribution and the elastoplastic failure process of the joint have been studied respectively, which can be referred for design of K-Joints of steel tube towers.
Abstract: The Gangneung and ± 500kV DC divider Longquan Converter Station external insulation flashover is analyzed. That the occurrence of flashover voltage divider reasons: First, hydrophobic composite casing completely lost; Second, the composite casing sheds less characteristic shape parameters; Third, the mean composite casing grading ring structure is irrational. Flashover occurs mainly due to hydrophobic composite casing completely lost, followed by grading ring structure is irrational. On this basis, for the voltage divider of the structure and nature of the incident,Propose a fundamental solution to the problem of thought is required by this article shall be electrical, mechanical and hydrophobic properties in the selection of composite insulation material casing; by down grading ring center distance and diameter of both grading ring composite casing ensures creepage distance and the effectiveness of dry-arc distance and the design value close to the main principles to re-design of grading ring ; the proposed umbrella out of composite casing greater than or equal 70mm, 70mm at least to re-pitch the umbrella design umbrella. Also suggests that the casing can be taken outside the insulation in the composite surface coating to enhance RTV-Ⅱ antifouling coating to increase the flash intensity of treatment measures of external insulation.
A new neutral point operation method was proposed with respect to the problem of compensation degree of arc-suppressing coils in 35 kV power grids of mountainous areas and the problem of unbalanced three-phase voltages. This method can not only maintain a balanced three-phase voltage, but also improve the arc-suppressing ability. A lot of calculations of the static process were conducted, and results proved that the operation method proposed in this paper is effective and feasible to improve operation ability of 35 kV power grids in mountainous areas and reduce lightning tripping rate.
Under the new situation of power grid development and new requirements of With the development of power dispatching automation systems of smart grid, it is necessary to build an unified city and county dispatching automation system featured as being pragmatic and technologically advanced. Based on the analysis on management and construction mode of several city and county dispatching automation systems, and combined with the actual situation of power grid system in Jiangsu province, a scientific, reasonable and effective construction scheme for city & county integration dispatching automation system was proposed, which contributed to the reform of city & county dispatching management system.
The telecommunication system is one of the most important parts of the high voltage direct current(HVDC) transmission system，since its operation status directly affects the control and protection systems. In this paper，the protection components which would be affected by faults of the telecommunication system were introduced first; then based on operation examples，the defects of using the equipment status of another station as the opening or locking conditions of some protection systems were analyzed，and some useful suggestions were discussed. At last, it was explained that attention should be paid to the backup protection when the HVDC system was shut down under telecommunication fault conditions.
In the first UHV AC testing demonstration project of China, 1000kV Jindongnan Substation adopts 1100kV gas-insulated metal-enclosed switchgear (hereinafter abbreviated as GIS), which is the first UHV AC GIS operating commercially in the world. Because of high voltage and large capacity, the design of the earthing system for this equipment possesses new characteristics, and concerning the actual construction conditions we proposed the concept of setting auxiliary ground grid. By analyzing and calculating the configuration of GIS, number of earthing point, power-frequency short-circuit current and lightning impulse current probably through, quantity of ultra-high frequency current, finally, we confirmed the size of the auxiliary grid. This article shows the earthing current value through each position of GIS and which is verified by current-resolution.
According to SDJ 226 "Crimping technology regulation for overhead transmission line and the grounding wire", when 1000mm2 conductor is crimped, there is serious phenomenon of untwisted strand, combined with the characteristics of 1000mm2 cross-section conductor, make some measures to remedy untwisted strands, these measures are proved effective and feasible by experiments, it plays an active role in improving construction equality of large cross-section conductor.
In 2008, the icing disaster in south China caused extensive damages to the transmission towers. Based on a study of damaged towers, a close wire-pulling tower-strengthening method was proposed. The pulling wire starts from the hanging point, passes through the supporting frame, and is finally fixed at the tower leg. The close pulling wire strengthens towers by utilizing the sufficient anti-pulling force of the tower legs.
Abstract This paper introduced the test running process of dingzhou power plant’s third unit after WFGD bypass blocked out.The effection caused by bypass blocked out and the corresponding resolvents are sxpatiated.Some of this paper’s emphases are those factors which affect the reliability of this unit.
The main material used in the cooling circulation water pipe for nuclear power is Q345, large diameter, thick plate, a plurality of weld seam, short space distance between reinforcement ring, and big constraint. Heat treatment shall be conducted as a whole in the furnace after the completion of welding operation in order to eliminate the stress. The heat treatment procedure is that the temperature of 600 ℃ shall be reached by heating and keep it for 2h then cool it in the furnace naturally .
Many low-voltage converters are adopted in direct air-cooled auxiliary power systems, and a lot of harmonics are produced on the inlet and outlet sides of converters. In this paper, harmonics of direct air-cooled auxiliary power systems were calculated based on a 2×600 MW direct air-cooled power plant; the field measured data validated the calculation results; and harmonic control measures were put forward. KEYWORDS: direct air-cooled；auxiliary power；converter； harmonic analysis；harmonic control measure
Based on the tilting bearing pad burnout occurred during the initial rotation of the turbine, Unit #1, Huanen Haimen Power Plant, we analyzed the cause of the bearing pad burnout and the solution, summarized the main factors which cause titling bearing pad abnormal temperature and vibration during the initial rotation, commissioning, running of the 1000MW ultra -super-critical parameter unit, offers the effect for reference for installing, commissioning and running of the turbine of the same type afterwards.
