For the specific situation of Inner Mongolia, use of small isolated power generating system of wind power-led to provide electric energy, can ensure reliability, saving diesel fuel and protect the local ecological environment. In this paper the small isolated power systems was described as Wind / diesel / storage power generating system. This Article use sequential Monte-Carlo simulation method to evaluate the system reliability. According to the historical data of wind farm, establish the wind speed time series model, than calculate the output of WTG. Considering the units random failure, use generator and load models to obtain the battery time series model. To a sample system, quantitatively assessment a number of factors that affect the system reliability, such as the simulation sample size, the battery capacity, the battery charging and discharging rate and the WTG rated power and so on. The simulation results can provide basis for the wind / diesel / storage system reliable operation, and for the government and the power sector to promote wind / diesel / storage co-generation system to remote areas.
It is shown from the investigation of earthquake damages that the porcelain high-voltage electrical equipment in the power grids engineering is seriously damaged after the earthquake. Based on an investigation of the power grid damages in an earthquake, shaking table tests and finite element analysis (FEA) are conducted of the porcelain high-voltage electrical equipment in order to assess the applicability of the existing aseismatic design standards for electric power establishment. On the precondition of technical and economic rationality, some applicable aseismatic measures are proposed for better guiding engineering design. In addition, some suggestions are also proposed on improving the aseismatic capabilities for porcelain high-voltage electrical equipment.
The Ningdong-Shandong ±660 kV HVDC transmission project is the first worldwide DC power transmission project in ±660 kV voltage grade, where the single 12-pulse converter bridge is used resulting in the highest single valve volage and the largest number of series-connected thyristors. Based on the H400 valve developed by China Electric Power Research Institute (CEPRI) together with AREVA company of France, the valves applied in the project are optimized by introducing valve section capacitor and equipping with new shielding case verified through type test. Furthermore, the electrical design achievements of the thyristor valve in the project is reviewed.
The structure features and design approach for the converter valve of Ningdong-Shandong ±660 kV HVDC transmission project are introduced in detail. Considering the basic structure of the converter valve, the composition, structure design feature and functions are illustrated. Especially the structure design for valve tower and valve module are described in detail, including design for the shield structure of valve tower, suspension and support structure, valve framework, connection structure and etc. Furthermore, the seismic design and fire protection design of the converter valve are introduced.
As the core equipment for HVDC transmission system, valve control system is mainly responsible for triggering, monitoring and protecting the converter valve. In Ningdong-Shandong ± 660 kV DC transmission project, the working principle and design features of the valve control system are presented. In addition, the on-site operation is introduced, with focus on the problems of valve base electronics(VBE) occurring in the commmissioning and trial operation. Finally, effective measures and improvement suggestions are proposed.
Based on the control and protection scheme of H400 converter valve, the design and realization of interface between DC control & protection system and the control & protection of converter valve are illustrated in detail. The type and function of signals between converter control and protection (CCP) and valve vase electronics (VBE) are demonstrated, including optical control signals, electrical I/O signals and so on. The effectiveness and reliability of the control & protection interface technology of converter valve are proved by the application in the Ningdong-Shandong HVDC transmission project.
Valve base electronics, connecting thyristor valve and DC control & protection equipment, is of importance to control and protect the thyristor valve. In the ±660 kV HVDC power transmission project, the thyristor valve and the control & protection system are supplied by different providers. In order to verify functions and performance of the interface between thyristor valve and control & protection equipment, the real-time close-loop simulation tests are carried out, where the overall situation is presented, the key technical problems and countermeasures are discussed, and the verification results are proposed. Close-loop tests of thyristor valve base electronics and control & protection system lay down solid foundation for on-site commissioning and successfully putting into operation of the project.
The Ningdong-Shandong ±660 kV HVDC transmission project is the first worldwide DC power transmission project in 660 kV voltage grade, where the single 12-pulse converter bridge is used resulting in the highest single valve volage and the largest valve tower dimension. Therefore, it is difficult for valve testing. In this paper, the items and parameters for the insulation test of valves are introduced, and the difficulties encountered during the test as well as the coutermeasures employed are illustrated.
Thyristor valve is one of the most important devices within high voltage direct current(HVDC) transmission system, therefore as the foundation and precondition for the research and development as well as engineering application of the valves, complete type test should be carried out to ensure the safe, reliable and stable operation. The items and parameters of the valve operational test for Ningdong-Shandong ±660 kV HVDC transmission project are introduced in detail. Furthermore, the synthetic test method employed and test waveforms are illustrated. It is shown from the test results that the valve design for the project is appropriate and can meet the specified test requirements.
The malfunction and damage of transformer substations are reviewed by severe earthquakes at home and abroad in recent years. The main failure characteristics and causes of different power facilities, such as buildings, porcelain electrical equipments, transformers, bus and so on, are emphatically analyzed. In addition, the domestic and overseas research and development of aseismatic measures in transformer substations is introduced. At last, the prediction and expectation are proposed for aseismatic research of transformer substation．
According to the relationship between fiber strain and Bragg wavelength, the calculation methods of sags are obtained under the conditions of isoheight and non-isoheight suspension center of overhead transmission line. A real-time monitoring scheme of sags on power transmission lines based on fiber Bragg grating (FBG) strain sensors is proposed. As a result, the real-time sag values can be determined by the strain of the monitoring lines. It is shown from the simulation that the scheme is applicable to the real-time monitoring of sag variation more than 10m, and the accuracy of measurement reaches to 16 mm, which has excellent feasibility in the project application.
Large crossing of Luotou watercourse is the heart of transmission project connecting Zhoushan island and the mainland, of which the scale creates many records. However, the selection and manufacture of transmission wire is one of the core technical problems in the project. In this paper, the experiences are summarized of the design and manufacture for transmission wire, providing references for similar engineering practice in the future.
The towers for large-crossing transmission lines are usually high and located on the riverside or seashore, where the climate conditions are poor. As the operation requirement of the large-crossing towers is increasing, such requirements as comfort and convenience are also proposed for the tower-ascending facilities on the prerequisite for safety. The paper summarizes the functions and design method of various common tower-ascending facilities such as the shackles, ladders, elevators and tower-climbing machines, which can be used as a reference for designing auxiliary structures of large-crossing towers.
In order to provide references for the optimal design of radiator and operation of direct air-cooled condenser, the flow and heat transfer characteristics in fin channel are investigated by CFD simulation in this paper. The effects of face velocity and ambient temperature on heat transfer coefficient and pressure drop are discussed, of which the correlative expression are fitted. It is shown that both heat exchanger coefficient and pressure drop increase with the increase of the face velocity, and the ambient temperature has significant effect on heat dissipation capacity of the air-cooled cell. The results obtained are helpful for the design and operation of air-cooled system.
The formation mechanism and protection performance are introduced of the passive film formed by oxgenated treatment of boiler feedwater. A series of experiments about the protection performance of the passive film are conducted after oxygenated treatment of boiler feedwater is ceased in 1000 MW ultra-supercritical units. It is shown that the passive film is also protective for a long period. Furthermore, it is feasible for the boiler feedwater to be discontinuously oxygenated.
With the coal-fired units large-scale in China and for reducing auxiliary power rate, the draft fan and the booster fan for desulfurization are combined firstly in 1 000 MW unit and driven by the steam turbine. The operation mode, sequential control and automatic adjustment(including stationary blade control, speed control and RB control) change for the turbine-driven fan under various operation conditions of units. Therefore, from the engineering application point of view, the traditional control strategies must be modified by field tests, for achieving the above control and ensuring the safe and stable operation of the units. After repeated trials and optimizations, the auxiliary power rate is reduced 1.27%. The difficulties, key points, problems and solutions during the control are summarized, providing references for other units saving energy.
The direct firing pulverizing system is dominant in the coal pulverizing system of large-scale coal boiler. The performance of pulverizing system is discussed matching with 2×1 000 MW ultra-supercritical boilers of a power plant. The speed characteristics of the dynamic separator, the adjustment test for grinding roll loading pressure and mill capacity characteristics are analyzed. Furthermore, the effects of mill outlet temperature, ventilation rates and grinding bowl differential pressure on mill capacity are investigated. As a result, the economic operation parameters for the coal pulverizer are obtained, that could enhance the output, reduce the single consumption and improve the running economy of the units under proper coal fineness and uniform index.
The boiler steel frame tends to be larger in scale and more complicated in system. Traditional 2D drawings can hardly satisfy the requirement of structural constructions. This article focuses on the imperfections of 2D drawings in expressing 3D images, and a 3D parametric modeling method for boiler steel frame is proposed. Based on the secondary development of CATIA software, the 3D models is constructed with the information given by 2D drawings. Meanwhile, a management system for engineering assembly parts is designed according to statistical methods of engineering management, by which the 3D parametric modeling for boiler steel frame is realized, the overall situation of the engineering structure intuitively embodied, the statistical management for the parts acquired, and the lofting and pre-erection outfitting for the parts are avoided .
With further promotion of energy saving, the induced draft fan merges with the desulfurization booster fan in No.3 and 4 units of a power plant, and the fan is driven by turbine instead of the electric motor. The control strategy of furnace draft, special plumbing configuration, parallel tests for fans and abnormal condition analysis are discussed in this paper, proving that the fan driven by turbine is innovative and controllable. It provides references and is worth while popularizing its application from the type selection, debugging, running and refomation of auxiliary engines in large-scale power plant.
The T2D750/22 gin pole with double rockers are investigated, aiming at the construction characteristics of two 370-meter high towers in the large-crossing transmission project between Zhoushan island and mainland. The innovative technologies of the gin pole include calculation of violent typhoon resistance at high attitude of island, hoisting and reeving system, anti-interference device of hoisting and luffing rope, bilateral moment control system, anti-collision device for the rocker, hoisting system for lifting mast section and SC60 frequency conversion construction hoist etc.
According to the demand of checking contact potential in substation, the material insulating properties of operating insulation ground floor are studied in this paper. The most suitable material and thickness of operating insulation ground floor is proposed by test and theoretical analysis. In addition, it is shown that not all the materials commonly used in substation meet the needs of safe operation in substations.
It is shown from the economic and technical analyses of aluminum and copper core cable, that the reliability of aluminum core cable is lower than that of copper core cable. However, aluminum core cable is competitive in reducing the costs of power grid construction because it is cheaper than copper core cable. Therefore, the domestic application of aluminum core cable is reviewed, and the obstructions to popularize application are analyzed. Some constructive suggestions of aluminum core cable applied in Jiangsu electric power grid are proposed.
Physical efficiency identification and quantization of power transmission and transformation project is of importance to the benefit analysis of economic evaluation and post evaluation. According to the features, position and role of the project in the power grid, the corresponding physical efficiency is identified. Combined with the networking power transmission and transformation project and based on the power grid, the quantization calculation methods for the physical efficiency are discussed, by using the balance analysis method for the power system.
The operation optimization tests of cold end system are conducted by double speed operation innovation of water circulation pump in two 1 036 MW steam turbine units of Huaneng Haimen power plant. According to the test data, the slight increasing curves of exhaust steam pressure and power are fitted, the correction formula of power is obtained, and the characteristics at variable operating conditions of condenser are calculated. Combined with the integrated coal and electrovalence comparison method, the operation mode for water circulation pump by double speed operation innovation is recommended. It is proved that the double speed operation of water circulation pump can reach the goal of energy saving and obtain the maximum economic benefits for the power plant.
The problems occur in converter transformer of ±500 kV Jingmen converter station are analyzed, including the change of insulators in tap changing switch, the oil leakage of and the false oil level during oiling. The corresponding solutions are further presented, which is proved to be feasible by the engineering practice, providing references to deal with similar problems in the future project.
Through the analysis of main difficulties of pits allocation for mountainous area transmission line, a new method for repetition measurement and pits allocation is proposed based on the global position system(GPS) and theodolite. It has been found that the method applied in the pits allocation for mountainous area transmission line is efficient, and of positive effect for lowering the construction cost, shortening the negotiation time for crop compensation, reducing external interference and dangers, and also protecting the environmental resources.
The technical problems, such as the traceability of the construction quality, anti-deformation of shared support, clean control inside the electro-polished tube, and applications of groove pipes, are discussed in this paper, which occur in the pipe construction of balance of nuclear power plant. Furthermore, the corresponding technical measures are established combining with the practical condition, which are proved to be simple and effective by the on-site inspection, providing references for the pipeline construction of balance of nuclear power plant in the future.
For the cooling tower, the distortion and breakage will occur due to constructional deficiency, concrete cracking and spalling, freeze-thaw rarefaction, deflation cracking, acid etching of air and rainfall, and temperature stress by muggy insolation and shrinkage etc. The internal causes, harm and influence for the breakage are analyzed combining the project practice. The maintenance and reinforcement techniques are introduced including gunite reinforcement, trap strengthening, and bind reinforcement etc. Aiming at various flaws and breakages, new maintenance techniques are proposed, providing references for the maintenance and reinforcement of cooling tower.
