In order to exactly evaluate wind load on a photovoltaic array and determine the actuator axial force of tracking systems, a new wind load distribution model of photovoltaic array was proposed on the basis of the comparison between Japanese code and Chinese code, combined with the results of wind tunnel experiments. In detail, the wind pressures on the photovoltaic array had inhomogeneity, but roughly in trapezoidal distribution. The proposed model could provid a reference for the fine design of the photovoltaic structure as well as determination of the actuator axial force.
In recent years, the wind power installed capacity grows rapidly in China, but the wind power production restriction problems gradually emerge. According to the plan, the future main form of the wind power is large scale development in China, which continues to present the fast growth momentum. In order to guarantee the effective consumption of wind power, the consumption market and strategy of wind power was studied combining the national conditions of our country. The characteristics of domestic and foreign wind power consumption were compared, and focused on the differences and applicability of consumption strategies, according to China’s wind power development and planning. Finally, this paper researched consumption market and demand of wind power in China with the method of cycling loading balance, and proposed some related suggestions.
This paper introduced the definition of digital design in substations，as well as its importance and necessity. And the application of digital design in Lhasa ±400 kV converter station was described in details. We improved the efficiency and quality of design by digital design, as well as preliminarily implemented the flow design and corporation between different majors during the engineering digital design process based on the digital design platform. The effect of digital design was showed through the numerical handover in Lhasa converter station project.
As a new voltage class in China, the ground clearances and crossing clearance of the ±1 100 kV transmission line have significant impacts on project cost, which is one of the key technical principles in transmission line design. Based on the design and operation experience of ±800 kV UHVDC transmission line, the determining principle was suggested for the ground clearance and crossing clearance of conductors in ±1 100 kV UHVDC transmission line. The electric field effects were calculated and analyzed at different section of conductors with different split number, split spacing, electrode spacing and ground clearance. In the end, combined with the design and operation experiences of ±800 kV HVDC transmission line, this paper presented the crossing clearance and corridor width of conductors in ±1 100 kV UHVDC transmission line, which could provide reference for further engineering design.
Based on the development goal of smart grid, the function and system structure of smart substation was introduced. The smart substation system was divided into process layer, spacer layer, station control layer and grid-province production management system. Some key technologies for the construction of smart substation was proposed, including primary equipment intelligence, information network and on-line monitoring. Finally, based on the concept of free distribution function of IEC 61850, this paper analyzed and consolidated all sorts of functions of the substation, combined the process layer and the spacer layer of smart substation into the equipment layer, and put forward a intelligent substation system structure which could face the future and adapt to the requirements of smart grid.
The compound foundaiton with short pile and anchor is a new type tower foundaiton that is applied in the rock foundation covered shallow soil layer. Based on a 500 kV transmission linge project, the new type foundaiton was designed, and 6 kinds of numerical simulation model were studied with FLAC3D finite element program for this foundation. The results show that the compound foundaiton with short pile and anchor can meet the load requirements of transmission line tower foundation, the short pier using anchor at bottom can significantly improve the foundation’s uplift bearing capacity, but the improvement of anti-overturning capacity in not obvious. In view of this situation, it can improve the anti-overturning capacity of compound foundation by enlarging the upright diameter and increasing the buried depth depth that is much more effective.
In tradition, expanding head in certain size was set at the bottom of dredged foundation in undisturbed soil in order to increase the foundation’s uplift bearing capacity. For the transmission line tower with large load, uplift stability analysis was no longer a key factor for foundation design. However, expanding head was made huge to satisfy the shearing requirement of concrete, so that it was uneconomic and unsafe in the design process. In view of the above engineering problems, The column foundation without expanding head in undisturbed soil on loess was taken as a research object in this study, and two test sites along 750 kV Lanzhou-Tianshui-Baoji transmission line were selected to carry out the static load test of undisturbed soil column foundation under uplift combined with horizontal loads. This paper studied the variation of load-displacement and the failure mode of foundation soil, obtained the bearing capacity of each test foundation, and calculated the value of side friction.
According to the load characteristics of transmission line, this paper analyzed the current transmission-line codes between domestic and overseas, compared the tension calculation under main working conditions combined with examples. The results indicate that the tension loads derived from GB 50545—2010, which are treated as independent variables in calculation and loads combination, are larger than others derived from the other codes: the earth wire tension increases by 16%~26% and the conductors tension increases by 12%~16%.
This paper established a three-dimensional (3D) precise calibration model for the phase distance of approach span. Based on the oblique parabola theory and 3D coordinate conversion technology, the implementation method of the 3D-CAD interactive software was suggested. Finally, the feasibility and the reliability of this method were verified by a project example.
The feasibility of application of wind-photovoltaic-energy storage (W-PV-ES) hybrid power generation technology in the station power system at 500 kV substation was analyzed and different schemes were designed. At present, the W-PV-ES hybrid technology is not suitable for the backup power system but can be used in the emergency power system. The W-PV-ES emergency power system can make full use of the nature energy source, improve the reliability of station power system, as well as supply power to the key equipments when all other power is lost.
The reasonable selection of circulating pump configuration and the optimization of operation mode are the key technology of circulation water system in thermal power unit, and the important step of energy saving and consumption reduction. This paper suggested that the optimal operation with multiple load cases of meteorological conditions and load change should be considered at the election stage of circulating pump configuration, in order to achieve the comprehensive optimization of initial investment and operation economy. Taking a 1 000 MW thermal power unit for example, the technical economy was compared between various configuration modes of circulating pumps, and proposed a recommended scheme, based on the optimization results of energy saving in monthly operation.
Turbine bearing-pad temperature and shaft vibration have significant diversities on different nozzle-steam distribution, through modeling analysis of rotor-load; get the rotor-load characteristic on different nozzle-steam distribution. Aimed at the Diagnostics of bearing-pad temperature and shaft vibration change on nozzle-steam distribution of CLNZK660 turbine of HTC, verify the theoretical analysis, and summarized the laws of different nozzle-steam distribution’s influence on bearing-pad temperature and shaft vibration qualitatively, then given the reasonable selection method and experience of nozzle-steam distribution, to provide the engineering application value to get the turbine to achieve the sequence valves adjustment.
This paper introduced the specified value of composite insulator’s design safety factor in the design code for overhead transmission line, and compared the force condition of suspension string and tension string in different conditions, such as ice, strong wind and annual average temperature. According to the comparison of meteorological data in several typical areas, this paper pointed out that the design must be different between tension string and suspension string, due to the operational condition of tension string was worse than that of suspension string, and the creep in operation life period of tension string was more serious. Finally, the value of design safety factor was suggested for composite insulator tension string.
The ultra supercritical unit with the high temperature parameters and the large capacity has been developed in order to achieve the high efficiency of thermal power units and the clean energy use. However, the steam temperature and pressure of thermal power units have been further increased, which present more stringent requirements for the material performance. This paper summarized the selection approach of heat resistant steel for the different parts in ultra supercritical units, as well as the existing problems in the using process of heat resistant steels. Furthermore, the development tendency and the material requirements were reviewed for 700 ℃ultra supercritical units.
Through the operation experience and statistical analysis, the state variables of detection can be got without cutting power, which can effectively reflect the condition of power transformer. Based on the morphological theory, this paper presented a hybrid filter for on-line monitoring dates which was combined with the open-closing filter and close-opening filter. The evaluation function was established by eighteen state variables which were got without cutting power, such as partial discharge, oil chromatography, casing leakage current, casing dielectric loss factor and so on. A multilevel evaluation model was also proposed based on the evaluation of state variables, parts and the whole of transformers, which could be used to evaluate the condition of working transformer.
In the context of climate change, China's power industry undertakes the important task of reducing emissions. Distributed energy has been an important reduction option for power industry. In this paper, based on the review of important literatures, important factors affecting renewable energy generation (such as cost, technical maturity) are analyzed. Combined with factors such as resource potential, economic development and environmental constraints, China renewable energy optimization model, CREOP, is constructed. The model predicts the potential of renewable energy generation in 2020; explores the development characteristics of various power generation technologies and their trends of unit investment cost. The results have a strong reference for long-term energy planning in China.
According to the scheme selection of 220 kV double-circuit transmission lines undercrossing 500 kV transmission lines, this paper analyzed the restricting factors of undercrossing scheme. Some measures were suggested such as changing suspension form of ground wire, arrangement mode of conductors and insulator string type of jumper wires. Finally, this paper designed and optimized the undercrossing tower, and proposed a double-circuit tension tower with olecranon-butterfly type. The engineering practical application proves that this tension tower has a good promotion prospect, and can provide a feasible solution for 220 kV double-circuit transmission lines undercrossing 500 kV transmission lines.
The average elevation of ±400 kV DC Golmud-Lhasa transmission line project is 4 650 m. Based on this project, according to the characteristics and difficulties of foundation construction in plateau frozen soil district in Tibetan, this paper studied the key technologies of tower foundation construction, and suggested some foundation construction schemes, which could provide references for other transmission line constructions in plateau frozen soil district in China.
The extra strong aluminum conductor steel supported (ACSS) was applied in Lihui-Zhanwang 220 kV double circuit transmission project. Based on this project, this paper studied the construction technology of fabricated stringing in continuous strained section. The theory and method of line length calculation and fixed length manufacturing was investigated for fabricated stringing projects. Finally, this paper introduced new strain clamp technology for fabricated stringing projects, as well as suggested the solution for line length error.
Based on the harm of NOx and the national environmental protection policy, the selective catalytic reduction (SCR) de-NOx reconstruction project was implemented in Huaneng Fuzhou Power Plant. This paper introduced the difficulties and characteristics of the project’s design and construction, such as the engineering steel structure, the SCR denitration device, the storage and preparation system for reducing agent, the injection and mixing system of ammonia/gas, and so on. Moreover, the design and construction problems were analyzed, and some suggestions were put forward, which could provide an important reference for other de-NOx reconstruction project in coal-fired power plants.
This paper introduced the structure characteristics of HD1080A half-speed steam turbine that was produced by DFSTW using the French Alstom technology, and studied the installation technology and procedure of the turbine, especially the key technologies of the adjustment for radial through-flow gap in high, intermediate and low pressure cylinder, the rotor center finding and the vibration isolator release. The Installation experience could be a reference for similar projects.
Currently, the environmental protection department and power generation companies pay more and more attentions to the anticorrosion problems on wet-method desulfurization chimney. Under this background, this paper discussed the construction scheme of chimney inner pad anticorrosion project for Guangxi Heshan Power Plant, as well as the construction methods for the key positions, such as the construction joints, the tube wall split bolt holes, the embedded reinforced head roots, the construction connection joints with new-old pouring material, the pouring material surface and so on. These practical and reliable construction methods that focus on details can be the reference for the similar projects.
