The external flow filed of the air-cooled island is numerically simulated by CFD for a 2×600 MW direct air-cooled unit. For the wind speed higher than 7 m/s, the combination of hot air recirculation and downdraught of the air cooled condenser results in the reduction of heat exchange efficiency. Therefore, fixing lower windbreak with curved surface upon direct air-cooled condenser is considered. Furthermore, the effects of lower windbreak height on average heat exchange efficiency and flow capacity of fans are discussed. It is shown that the optimum height of the windbreak is 85 m, where the fan flow and heat exchange reach to the maximum. Especially the average heat exchange efficiency of the first two lines of fans increases 1703% than that without the lower windbreak. It provides theoretical evidence for the structural design and optimization of the air-cooled island.
Vibration characteristics of fan bridge are determined by the structure. Based on ANSYS software, the stiffness and vibration bands of two types of ACC fan bridge structures are analyzed by modal analysis. Furthermore, the frequency response curves under three different vibration loads are calculated separately by harmonic response method, which of the two fan bridges are contrasted. It is demonstrated that the vibration characteristics of fan bridge are improved by structural optimization.
It is difficult to access to the grid planning because of intermittent, distance, mass, and other characteristics of wind power ,and significant impact on the construction, production operations, security and stability. In this paper, the nominal power plant is proposed to solve problems that large-scale wind farms grid in the existing real-time scheduling mode of power system. The equivalent of the wind turbine and the conventional water, thermal power and other energy storage devices of a region is achieved to control power grid.The feasibility is proved base on a virtual power plant data model and data validation using the actual network operation data of a million kilowatts of wind power .
Both m method and p-y method are used to study the lateral bearing capacity of pile foundations. The comparisons between two methods are performed combined with the engineering practice. Based on Zhoushan-Mainland large-crossing project, the effects on lateral bearing capacity and distortation of pile foundations are analyzed. To optimize the thickness of pile cap, pile cap and pile group interaction is considered.
The layout of electric apparatus, electric connections and fittings design is the key factor to ensure safe electric clearance, effective control of corona and electric field intensity, reliable and safe operation in valve hall of HVDC converter station. In ±500 kV Baoji converter station, which is the first one completely utilizing domestically manufacturing equipment in China, the electric equipment selection and design features of valve hall are analyzed. On the basis of the above analysis, the design feature and characteristics of the fittings are introduced in detail according to the special requirements of electric connections in valve hall. Finally, the management experience and electric design of valve hall are summarized.
Base on quasi-steady theory and Davenport spectrum, wind vibration coefficients of 1 000 kV three-span trussed frame are calculated, which is compared with that calculated by the standard method. It is shown that the wind vibration coefficient of 1 000 kV three-span trussed frame are higher than that of single tower, which calculated by standard method are conservative for edge tower and dangerous for middle tower. The results obtained in the paper need to be given attention to in engineering design.
The grounding resistance measurement instrument fails in high soil resistivity because the grounding resistance is too high of auxiliary grounding detection rod from the theoretical analysis. In order to improve the sensitivity of measurement instrument, it is proposed to increase the length and diameter of auxiliary grounding detection rod, enhance the water content of soil and apply salt for decreasing resistance. The correctness and reasonability of the proposed method are validated by field experiment.
The grounding performances and technical economy of common ground electrode are different from those of regular ground electrode, of which the comparisons between regular electrodes and common electrodes can help engineers optimizedly design electrodes. According to the major modes of multiple convert stations operating in synchronism, the grounding current, ground resistance, and economy etc are analyzed and compared for regular ground electrode, one common electrode and two common electrodes of multi-stations. It is shown that common electrode is better than regular electrode from both environmental influence and economy aspects, where the electrode site is exigent for one common electrode of multi-stations. If better electrode site is available, one common electrode has smaller electromagnetic influence range of step voltage than that of two common electrodes, of which both are on the same levels in the construction investments.
By the calculation and analysis of intensity of power frequency electrical field for typical transmission line over buildings, the electric field with height limit is investigated based on the technical code for designing 110~500 kV overhead transmission line. Furthermore, the height of the tower and intensity of the power frequency electric field are optimizedly calculated, providing references for the design and construction of new power transmission lines.
The site resource of nuclear power is very rich in Shandong Peninsula, where is suitable for constructing large-scale nuclear power base. By the analysis of the power transmission scope and direction of nuclear power base, the optional transmission plan of Haiyang, Shidaowan, Rushan and the fouth nuclear power plant is proposed. The transmission plan is recommended by technical and economic comparison, providing references for construction of large-scale nuclear power base and power grid planning.
Combined with the features of HG-1165/1745-YM1 boiler in a power plant, the tests for burning bituminous coal mixed with lignite is preformed. For mixing lignite, the optimal transformation is proposed, the technical problems occurring in the engineering practice discussed, and the corresponding economics analyzed.
Based on the local non-uniform section steel column of the conventional island in Taishan nuclear power plant, experiments of three specimen columns with 1 to 5 proportion subjected to eccentric load are carried out to study the failure mode, strain, deformation and bearing capacity. It is shown that the large slope or abrupt change of section has detrimental effects on the eccentric compression performance, leading to the reduction of the yield load and increase of the deformation. Furthermore, local strengthening has little impact on improving mechanical behavior. It could provide a reference for the design of similar structural components.
To improve the capability of abrasion-resistance of the grinding roller, the NiCr-Cr3C2-Ti-C compound welding surface is prepared and taken NiCr foil, Cr3C2 powder Ti powder and C powder as raw materials based on TIG method. The phase structure, microscopic organization, component distribution and the hardness are studied by SEM, EDS and XRD. It is shown that the welding tissue is composed by Ni-based sosolid, TiC and Cr23C6 etc, and its highest hardness is between 1800 and 2000 HV. By wearing test, the abrasion of NiCr-Cr3C2-Ti-C compound welding surface and the other materials are compared. It is shown that the NiCr-Cr3C2-Ti-C compound welding surface has better abrasion-resistance than the other materials, and can be used to improve the capability of abrasion-resistance of the grinding roller.
According to the design of feed-water system process and arrangement of one nuclear power plant project of CPR1000, a universal model from deaerator outlet to steam generator inlet is built for steady and transient analysis with the result of piping resistance calculation by using Flowmaster computer package. The transient analysis indicates that the decrement of steam generator feed-water is allowable during the process of tripping one pump and starting-up the standby pump. The standard model and analysis are demonstrated with a certainty commonality.
In the present retrofit of DCS(distribute control system) in Fengcheng power plant, the soft measurement method is applied, and the analogue quantity feedback of the actual position is accurately obtained by using the opening, closing and stopping signals of motor drived valve of main feedwater. As a result, the production and labour cost are reduced, as well as some intuitionistic and reliable data are provided to operators. Furthermore, the BIR(boiler input rate) dynamic feed-forward control idea which is adopted in the FTCCS(furnace-turbine coordinated control system) of 600 MW supercritical unit, is applied in 300 MW units successfully so that load response ability is raised and control quality improved. The successful application of the control strategies not only has great significance to the production management of the company, but also provides useful reference for the optimization design of similar project.
The fuel for gas turbine is normally natural gas or heavy oil, which used in the IGCC(integration generation combined cycle) is syngas with main compositions of H2 and CO. The variations of composition and heating value of fuel will lead to the requirement of some modifications for gas turbine, and the reset of operating condition points. In the paper, the characteristics of gas turbine for firing syngas are firstly analyzed, and then some measures to improve the performance of gas turbine introduced.
The chemistry check-up is made in the first maintenance of the supercritical once-through boiler 600 MW units in Henan Province. It is shown that the deposit rates are high on the water-cooled wall, coal economizer, and the turbine blade. The formation of salt deposition is complicated in the turbine blade. According to the operational status, the reasons are analyzed and the suggestions provided.
By summarizing the pollution emission of thermal power in China, the technological and economic analysis are carried out based on exchange value of pollution emission, environmental protection technology and equipment demand etc. By valuing the producing pollution emission, the demand of reducing emission and thermal power environmental protection industry for the next 20 years, it can be seen that the space of environmental protection industry of thermal power in China has wide development prospects. But at the same time, there are a series of problems such as inadequate investment, cost difficult to release, lack of laws and regulations, that need to take measures in the financing channels, recovery mechanism, the regulations system, etc.
Fiber reinforced polymer(FRP) is one of the most ideal materials for building transmission tower. The elastic and inflective theory about FRP axial compression component is introduced firstly. The equivalent initial bending rate is obtained based on the tested value of ultimate bearing capacity so that the effects of initial bending, residual stress, bushing at the ends and etc are considered. Furthermore, the critical stress and stability coefficient are derived, on which the effects of diameter-thickness ratio and ageing are studied.
The self-excitation power supply is a self-power supply technology for electronic transformers at high voltage side. In this article, the design principles and configuration methods are introduced of adopting complete self-excitation power supply in high-voltage substation. A technical improvement process and actual operation effect are illustrated of 110 kV substation in Mianyang. It is shown that the application of complete self-excitation power supply transformers simplifies system structure, exempts from periodic maintenance requirements for power supply equipment, improves the stability of the operation. The expected service life increases from 1~3 years to 15~20 years. Therefore, it is worthwhile popularizing the power supply technology to a large scale.
According to the construction features of overhead transmission line crossing high speed railway, the structural characteristics of different crossing frames and protection nets are summarized, of which the applicable conditions and advantages are analyzed and compared. In addition, safe distance for crossing is investigated and verified, providing references for similar construction design of overhead transmission line crossing high speed railway.
In pedestal construction of steam turbine nowadays, split heads is used as the prevailing rebar strengthening method for which the welding workload, time required, and rebar wastage are considerable. Based on the shortcomings of the traditional method, a triangle stay bearing replacing split head for pedestal rebar strengthening is introduced, where the construction time may be shortened, rebar be saved, and hence economical benefit is enhanced.By using triangle stay bearing, duration can be shortened, rebar can be saved hence more economizing.
Volute casing is the major component of CRF pump in united water pump house of nuclear power station, whose shape looks like a hodmadod. It is placed at the top of the water channel in PX pump house, connecting with the recycled water corridor. Taking Ningde Nuclear Power Station for example, the installation technology of volute casing formwork is introduced from the lifting and positioning of pre-cast concrete pieces of volute, grouting in the bottom and seam crossing of volute, the installation and reinforcement of the formwork of water corridor, and the installation of piezometer tubes in the outlet of circulating water and other aspects, for providing references to similar projects.
