The strength of grid structure and the constant process of smart grid technology both provide the basis for large-scale power flow. This paper analyzed and summarized the status and trend of power flow development in USA, EU, Russia and Brazil, and got the main influencing factors of power flow. According to the actual situation in China, an enlightenment from development of power flow overseas was suggested for the electric power industry in China.
This paper study the problem of our country’s electrical energy flow optimization. Two optimization model, whose objective functions are minimization transmission costs and maximum electricity price competitiveness respectively. The the parameters needed for the problem and optimization algorithms are also introduced in the paper. Furthermore, by using our country actual data , the paper give the optimization results of two model. Finally, based on the results of two optimization model, one resonable electrical energy flow suggestion of our country in the future is given in the paper.
According to the power system planning problem of power flow and scale optimization, this paper designed and implemented a specific software solution. The solution can not only decouple the interface with the algorithm, but also introduce the concept of general algebraic modeling system to the construction of optimization model, which can realize the decoupling between the optimization model and data. The design idea makes the system has a high scalability, and suitable for the programming problems that are still in the development and improvement process, such as power flow and scale optimization problems.
Analytic mechanics-based modeling, multibody system dynamics-based modeling and finite element method-based modeling are three common structural modeling approaches for wind turbines. The three modeling approaches were discussed based on their historical development and logical relations, common characteristics and development prospects. Furthermore, the three modeling approaches were comprehensively compared, which could provid a reference for the wind turbine system structural modeling.
After large-scale wind power and photovoltaic power is connected with the grid, the inherent intermittent and volatility of wind power and photovoltaic power may have adversely affects on the security and stability of power grid. With the rapid development of wind power and photovoltaic power generation, this problem is increasingly outstanding. So it is very important to development the technology research of large-scale battery energy storage system (BESS). The article respectively carried out comparative analysis on the converter and the filter, which were the components of power conversion system (PCS) as an important component of BESS. Based on the existing battery technology, the results show that the converter only containing DC/AC link and the converter containing Z-source network and DC/AC link both have the characteristics of higher energy conversion efficiency and simple control, compared with traditional converter which contains DC/DC link and DC/AC link. Compared with the traditional L filter and LC filter, the LCL filter can restrain high harmonics better, effectively reduce the inductance value, improve the dynamic performance of the system, and be less affected by the grid. Combined with analysis conclusion, the article put forward two new topological structures of PCS.
This paper put forward a control system of static synchronous compensator (STATCOM) based on the EtherCAT bus technology, which had the characteristics of flexible expandability, Flexible information allocation function, high transfer rate, very short data exchange time, and accurate synchronized clock. The control system used two EtherCAT bus nets: main control net and module net. The main control net adopted series communication mode, and had data sample slave, data input and data output slave, regulation and protection slave, and transient fault record slave in the main control net. The module net adopts stelliform communication mode, and all slaves are derived from the couples. There are regulation protection slave, transient fault record slave, and all module slaves in the module net. The regulation protection slave and the transient fault record slave belonged to two EtherCAT bus nets. Digital signals processor (DSP) was used in the regulation protection slave, the transient fault record slave and the module slaves, which could improved signal transmission and control speed, and meet the requirements of real-time control. The experiment results show that the control system can significantly increase the device expandability, allocation function and transfer rate, achieve precise synchronization. The control system can be applied in the chain STATCOM and other flexible AC transmission systems (FACTS) used chain converter, which has the characteristics of clear control purposes, easy to implement and stable control effect.
As the base of united planning system application, power grid planning research platform (PGPRP) is the first integrated platform system for transmission grid planning in China, which completes a large number of design research and technology reserves. Based on the review of PGPRP construction process, this paper summarized the construction experience of planning platform, proposed the principles that should be analyzed in the total design process, analyzed the key points of construction, forecasted the future development trend of PGPRP, and suggested recommendations for next step.
According to the demand of efficiency and operation safety in power system, it is extremely important to implement the risk evaluation of lightning disturbance for high voltage overhead transmission lines. However, there is no determined model and standard for the risk evaluation of lightning disturbance in transmission lines at home and abroad. Based on the improved analytic hierarchy process (AHP) and comprehensively considering the related factors of lightning disturbance risk, this article suggested a simplified model of lightning disturbance risk assessment, and carried out the example analysis. The results show that this model is effective and it could meet the requirements of the project application.
According to the fact that 220 kV outgoing lines were overhead in most of 500 kV substation, some improvement measures were implemented for the 220 kV hybrid gas insulated switchgear (HGIS) distribution device in 500 kV intelligent substation, such as the configuration integration for interval equipment, the optimization design for layout and framework. The layout optimization scheme included: the configuration integration and optimization for interval equipment, the design of large span bus beam and united framework, partial double outgoing line within single bay, and so on. Compared with the 500-B-4 universal design, this optimization scheme has advantages of saving 34.1% occupied area and 28.6% structure steel consumption with same equipment investment.
This paper compared and analyzed the difference between calculation methods of design wind speed recommended in《Minimum design loads for buildings and other structures》(ASCE/SEI 7-05 2006), 《Design criteria of overhead transmission lines》(IEC 60826 2003) and Chinese standard by statistical experiments. The research results can provide a reference for the survey and design of future international power engineering.
The extension of digital substation is different with the conventional, where the generic object oriented substation event (GOOSE) information of the entire intelligent electronic device (IED) is exchanged through switch, and the debugging device may access to same switch with other operating device. So it must eliminate the impact of the new equipment to operating GOOSE network and ensure the integrity of the secondary experiment for new devices, in the expansion process. Taking the interval extension of Xin’an I line in Zhiyan 500 kV substation for an example, this paper discussed the safety measures of new equipment and the implementation of debugging program in substation extension process.
《Guidelines for electrical transmission line structural loading》(ASCE 74—2009) is widely applied and used for reference in many countries over the world, which is very important to the electric power construction in our country and foreign projects. Wind load is the control load for transmission tower. So it is necessary to master the differences of wind load computation methods between Chinese code and ASCE 74—2009. This paper introduced the wind load computation formula for transmission tower by Chinese code and ASCE 74—2009, and detailedly compared the differences of basic wind speed, height variation factor of wind pressure, shape factor, wind load factor, topographic factor, icing load factor, yawed wind load computation method and so on. The results can be used as a reference for the technicians of transmission line engineering.
The project of 500 kV four-circuit on one large crossing transmission tower in Xijiang was introduced. This paper analyzed and compared the dynamic characteristics of single tower and tower-line system. Both in the single tower and tower-line system, the first modal is x-axis bending vibration, the second modal is y-axis bending vibration, and the third modal is z-axis torsional vibration. The y-axis bending vibration frequency and z-axis torsional vibration frequency of the single tower are smaller than those of the tower-line system. The results show that the structural system layout of large crossing transmission tower is reasonable and the wire can improve the bending stiffness of y-axis and the torsional stiffness of z-axis.
The relationship between bearing vibration and foundation vibration in 600 MW units was studied from the view of the linear velocity’s root-mean-square (RMS) value and linear displacement of control point’s vibration, based on the summary of the related standards and the experimental data, and the evaluation standards for the turbo generator units was also compared. Moreover, this paper investigated the composition of vibration energy at bearing chock and interference point, in order to provide reference for the further research of the relationship between units and foundations.
The general layout plays a pivotal role for coal-fired power plants, whose investment accounts for 10%~15% of the whole project static investment. And the layout optimization has a great influence on the operation management costs. Huaneng Haimen Power Plant made more attempt on general layout than other power plants in coastal areas, such as the coal handling gallery through the chimney, drainage taking by open channel in a maximum extent, and so on, which could provide reference for related projects.
In order to reduce the fault tripping times of thermal power control system caused by logic design, access mode of protection signal, installation, commissioning, repair, maintenance, and so on, this paper investigated the hidden troubleshooting for the thermal control system and the prevention measures for the system reliability, based on the fault’s cause analysis, treatment experience and lessons for the thermal power control system, and the specification requirements of ‘the Reliability Deployment and Accident Prevention of Thermal Power Control System’. The prevention measures were suggested form the view of lightning protection, anti-interference, turbine supervisory instrumentation, logic reliability optimization, wiring and piping, technology and supervision management.
Along with the steam turbine-driven IDF gradually applied in 1 000 MW turbine generator units, the related runback (RB) test has received more and more attention. Based on the analysis and summary of the debugging and RB test problems in a 1 000 MW turbine generator unit using steam turbine-driven IDF, this paper suggested the optimization strategy for the control logic of FDF and IDF. The RB test result proves the feasibility of the optimization strategy, which can provide reference for other units that use the steam turbine-driven IDF.
According to the national policy of energy saving and emission reduction, the gas bypass in desulfurization facilities should be dismantled in power plants. This paper introduced the successful application experience of seawater desulfurization technology in the ultra-supercritical coal-fired units in Huaneng Haimen power plant, and analyzed the problems caused by bypass diverter dismantled. The transformation for desulfurization facilities should control the flue gas temperature at absorber inlet, as well as avoid gas-gas heater (GGH) and absorber blockage, in order to ensure the qualified emissions index and safe operation, based on which a series of prevention measures and optimization technologies were suggested.
In order to reduce auxiliary power consumption and improve unit efficiency, frequency conversion transformation was implemented for the condensate pump in Huaneng Yuhuan power plant. The solution was suggested for the restrictive factors of depth frequency conversion of condensate pump which were the seal water of steam feed pump and the desuperheating water of low-pressure bypass in turbine. The operation tests were carried out for the condensate pump after depth frequency conversion, which included opening experiment of water-feeding main valve in deaerator, regulator parameter tuning of main pipe pressure in the condensate with frequency conversion control, switch test between variable frequency pump and general pump for condensate pump, frequency conversion adjustment test for condensate pump with condensate system fault occurred, and so on. The economic benefit analysis show that the depth frequency conversion for condensate pump can decrease the throttling loss to a minimum, and further reduce the condensate pump’s current and speed, when deaerator’s main valve is fully open, which can reach the effective energy saving.
The fatigue performance of E-glass fiber/epoxy reinforced polymer in transmission tower bars was investigated. The fatigue limit load of the material is performed in Up-down method followed by the analysis of the fatigue limit load and the displacement of the specimens. The results show that the fatigue limit stress of specimens is 246.75 MPa under 105 times in cyclic loading, the displacement amplitude of specimens increasing with loading adding is between 3.8mm and 4.9mm, the fatigue damage of specimens occurs at the joint due to the strength of which is lower than that of the material. Therefore it should pay attention to the strength of connections to meet the practical requirements under the fatigue.
The application situations of diameter-extended conductor for UHVAC transmission line projects were presented. Based on 1 000 kV Ximeng-Nanjing UHVAC transmission line project, the electrical characteristics, mechanical performances and the economic features of diameter-extended conductor and conventional conductors were compared. The results show that the diameter-extended conductor not only meets the electromagnetic environment requirements, but also can effectively reduce the project investment for UHVAC transmission line projects, under the precondition of satisfying the transmission capacity, which has great practical significance for the construction of environmentally friendly and resource-saving UHVAC transmission lines.
Ropeway transportation is the most economical method for goods transport in power line project with large height difference. The whole system consists of work rope, scaffold, goods container, driving device and ground anchor, etc, and the driving device is the most crucial. Based on the research of the ropeway used in other construction units, a new driving device was developed. It is suitable for the construction in 500 kV Danba-Dagang power line project with 1 700 m height difference, which can provide the technical guarantee for the successful completion of the project.
As the economy developed area, there is an urgent need to develop clean energy in Jiangsu province, such as natural gas power generation. In order to promote the healthy and orderly development of gas power generation industry, this paper researched the production & operation situation of four 9F gas-steam combined cycle power plants in Jiangsu province, summarized the situation of generation cost from 2009 to 2011, and analyzed the impact factor of generation cost. The research results show that the gas price, utilization hours and unit operation mode have important influence on the generation cost. Finally, this paper suggests the methods for reducing generation cost, such as increasing the generating equipment availability and improving unit operation mode.
There are many production processes in thermal power plant, and the significance of energy saving and consumption reduction is important for every process, especially flue gas desulfurization system. This paper studied the impact of entrance negative pressure of booster fan on the total power consumption of induced draft fan and booster fan with the same boiler furnace negative pressure in the unit operation process. The results show that the total power consumption of induced draft fan and booster decreases with an increase in entrance negative pressure of booster fan. The research results can accumulate the experience of energy conservation and consumption reduction for thermal power plants, and adjustment the direction for the unit operation.
It is difficult to arrange traction-tension space when transmission line lies in the mountains. The corner block is needed for the steering arrangement, under the situation that cannot arrange traction space or tension space in the line stringing center. The setting of corner block is important to the quality and safety of stringing construction. This paper investigated the method to determine the corner block’s numbers, location, and the ground anchor’s direction, according to the guidelines and practical engineering experience.
This paper analyzed and improved pulley hanging method for domestic 900 mm2 conductors with six-split, which adopted the mode of ‘3-tractor with 1-guiding 2-wire’. The three rounds specially developed on cable pulley hanging rack could make the arrangement and suspension method of pulleys with every towers’ pole hanging 3 three-wheel lines. The synchronous installation and hanging of insulators and pulley could simplify installation steps, improve the construction efficiency of tension stringing, and ensure the good mechanical property of towers, which could provide a convenient for the subsequent tight lines’ construction and accessories’ installation operations.
In the stringing construction process, some conventional mechanical equipment was unable to meet the load demand with the use of traditional stringing technology, which needed the equipment modification or the purchase for new equipment. Therefore, a new tension stringing technology with ‘2-tractor with 1-guiding 3-wire’ was put forward to make the existing equipment basically meet the load demand, which could avoid a large purchase of new equipment, as well as achieve the purpose of saving money and improving construction efficiency.
The follow-up engineering construction of riprap protection for 500 kV Hainan interconnector project has some characteristics, such as great difficulty in construction, high degree automation in construction equipment, widely involving in technology field. This paper introduced the present situation investigation, the design argument, the experimental research of submarine cable in the early period of the project, as well as the preparation of rock material and the control management in the construction process of the project. The rockfall pipe technology and remote operated vehicles adopted in the project both represent the advanced development level of ocean engineering technology in the world, which has the reference significance to the development of ocean engineering technology and the research of engineering measurement equipment in China.
