For developing the optimized scheduling system of hydropower stations of provincial power networks,the object-oriented technology is applied.The optimized object-oriented scheduling system is designed and developed by constructing the model-method library,abstracting generality characteristics,and separating the optimization algorithm and operation flow using interface technology.
The compensation of cascade hydropower stations is discussed.The allocation model of power generation benefit in cascade hydropower stations is proposed under multiple power generation subjects.The compensation weights of each hydropower station are confirmed based on total generating capacity.According to the weighting coefficient,the increased power output and increased benefits of each station are re-allocated.As a result,the benefits of hydropower stations will be optimized because each station changes its goal from price competition to whole benefits improvement.Furthermore,time compensation is also discussed in order to make reasonable compensation.
In the paper,the development procedure of online monitoring of HV equipment is reviewed,of which the problems and bottleneck for further development are pointed out.Furthermore,the concept and goal of smart HV equipment is discussed in details,which is compared with the traditional online monitoring.Based on this,the suggestions of converting online monitoring to smart HV equipment are proposed aiming at present construction of smart grid.
As an important component of strong smart grid,smart power utilization is direct to society and customer.It is an important carrier for the community perceiving and experiencing the achievements of power grid construction.From the user perspective of view,the influence of smart grid on users and the impact system are analyzed based on the two-way interactive services,the intelligent management of distributed energy resource located in the user side,and the intelligent management of electric vehicles and energy storing devices.It is shown that smart grid can meet multiple and diverse needs of user power utilization,reduce electricity costs,improve the utilization efficiency of the power grid effectively,improve customer service levels,promote the development of distributed energy resource,electric vehicles and energy storing devices,increase the proportion of power in terminal energy,and reduce carbon emissions substantially.
In the framework of the modern smart grid technologies,the optimal distribution of voltage sag monitoring device is an important research field in the study of power quality monitoring terminal.The installation location and monitoring scope of the monitoring device are described respectively based on the position vector and monitoring area matrix of monitoring device.The mathematical model of the optimal distribution of monitoring device is constructed by considering the specific requirements for distribution of monitoring device,and a 0-1 integer programming is proposed corresponding to the optimal model.Finally,the proposed method is applied to an IEEE-30 network to determine the optimal distribution of voltage sag monitoring device in the whole network,of which the correctness and validity is further analyzed.
The calculation of line loss for complex distribution network with distributed generation has new features.However,the traditional method cannot meet the demand for future distributed generation systems.In this paper,the radial distribution network with distributed generation is investigated.The common distributed power nodes are divided into PQ,PI,PV and PQ (V) types.According to the characteristics of each node type,the improved algorithm of forward and backward for power flow calculation is put forward.The voltage line loss is calculated for taking the system with 33 nodes as an example.Compared with the traditional distribution network,the system voltage is reduced for the distributed generation using asynchronous generator as the interface,while other interface forms play supporting roles to system voltage.
Based on the project of application and investigation of double-pole-composite strain tower of 1 000 kV ultra high voltage,the electrical test program of flexible jumper system in double-pole-composite strain tower is introduced.By the analysis of test result,it is shown that the electrical properties of the flexible jumper system can meet the engineering requirements. KEYWORDS：ultra high voltage；double-pole-composite strain tower；flexible jumper；electrical test；corona； radio interference
The successive blocks of bipolar three valves manifold occur in Yunnan-Guangdong UHVDC system.In this paper,the process of the accident are analyzed and the electromagnetic interference of measuring system analyzed.It is proved that the electromagnetic interference exists in the secondary devices of Suidong convertor station and the improvement measures are suggested by the simulation and experimental results.
The electromagnetic environment of 750 kV compact power transmission lines is not friendly due to its high voltage,short phase distance and high altitude.Generally speaking,as a result of the interaction of sub-conductors,the electric-field distribution on surfaces of sub-conductors equally arranged at circumference is nonuniform.The heterogeneity increases the electric field intensity on maximum surface of phase conductor,so that the radio interference and audible noise of the transmission line are increased.Therefore,the electromagnetic environment is improved by changing the arrangement of sub-conductors.The influences of optimized sub-conductors arrangement on the electric parameters of the transmission line are also discussed.The results obtained will provide references to the construction of UHV compact power transmission lines in our country.
Considering that the space for line installation is not enough,DC transmission projects for mid-and short-distance (800~1 300 km) in China recently are designed to be contrusted by±500 kV double circuits on the same tower,and the transmission capacity of single circuit is rasied from 3 000 MW to 3 200 MW,which lead to the increased loss,and more difficulty in the converter valve design etc.Aiming at the DC transmission project from Xiluodu to Guangdong,the feasiblity of the voltage raised from ±500 kV to ±535 kV or ±550 kV is studied,and the effects of three voltages are analyized on main circuit parameters,insulation coordination,main equipments,DC line design,loss and investment.As a result,the optimized operating voltage is given by a comprehensively technological and economic comparison.
The system specification description（SSD） is used to describe main wiring diagram and the matched logic node of substation. Based on the mapping relationship between the SSD model and the main wiring diagram of substation,the construction technology of the substation wiring diagram contained in SSD model is carried out by the scalable vector graphics（SVG） technology.
EPON（ethernet passive optical network）being the best choice for optical access network,has both advantages of PON(passive optical network) and ethernet,with high bandwidth,low cost,convenient operation and easy upgrade. Based on the composition,technical characteristic and network advantage of EPON,the feasibility and application scheme of EPON are analyzed in communication network of power distribution automation.
In HVDC converter station,the connection differential protection will be activated because of a trip of the last circuit breaker in AC Filter.In this paper,taking the UHVDC transmission project of Yunnan-Guangdong as an example,the software logic and related hardware circuit are analyzed of the last circuit breaker in AC Filter of the 6MD664 interval control unit,where the design defects and improvement are presented.
The parallel gap lightning protection device is beneficial to the existing lightning protection measures for overhead transmission line and has broad application prospects.The application investigation on parallel gap lightning protection device of composite insulators for the 110 kV overhead transmission line used in Dongguan Power Supply Bureau is presented in this article.A variety of parallel gap lightning protection devices are designed.The functions of its guiding lightning discharge,transferring frequency arc,homogenizing frequency electric field and protecting insulators and fittings are verified by tests.After optimization of the design to determine the electrical parameters and dimensions of the gap,the samples are developed and used in five 110 kV transmission lines.The operation situation of the parallel gap lightning protection of composite insulator for 110 kV line is introduced.
The planned hydro-power projects of Wudongde and Baihetan in the lower reach of Jinshajiang River are to be built soon after the pre-feasibility and feasibility study,where the single-machine capacity can reach to 1 000 MW.The new development for the feasibility research on design,manufacture and engineering application technology are summarized for 1 000 MW hydro-generator units,and the research emphases for the next stage presented.Based on the domestic technology,the studies show that it is feasible to design,manufacture and transport of 1 000 MW hydro-generator units in Wudongde and Baihetan,without big constraints existing.
The site selection of refuse incineration power plant has many influencing factor and is of severe social impact. In this paper,an optimizing algorithm for site selection of refuse incineration power plant is provided based on principal component analysis and back propagation (BP) neural network. The samples are selected by principal component analysis,as a result that a few samples can reflect as many sample characteristics as possible. The neural network is trained by Levenberg-Marquardt BP algorithm,and the training speed is improved.
The full-pouring busbar is adopted in 6 kV auxiliary power system in 330 MW units,which is applied at the first time in large power units of China.In order to guarantee the safe and reliable operation of the busbar,the methods of infrared thermograph,inter-segment contact resistance testing,insulation resistance testing and AC withstand voltage test are presented combining with the insulating structure of the full-pouring busbar.Furthermore,the dielectric power factor and capacitance are tested,and the BIM(betobar insulation mix)relative dielectric constant is estimated for further knowing the properties of the insulated materials.It is shown from the operation of the full-pouring busbar in recent years,that the on-line detection and off-line test are easy to implement,and the work load of maintenance and detection decrease substantially.
It is pointed out in the paper that the combined heat and power (CHP) enterprise should compete in the generation market.The coal consumption distribution method is introduced,and the revenue function for the CHP enterprise is presented for the first time.Based on the revenue function,the bidding strategy is made for the CHP enterprise to compete in the generation market.It is shown that the participants in the generation market should be classified into two parts including CHP enterprise and heat power plant.By considering the existence of two CHP enterprises and one heat power plant,the bidding process of CHP enterprise is discussed by the application of non-cooperative game theory under complete and incomplete information.It is concluded that the CHP enterprise should join in the competition of the generation market making the best of energy cascade utilization.
The feedwater flowrate is one of the important parameters in the thermaldynamic performance test of steam turbines.On the basis of the conventional heat balance,the matrix calculation model is constructed with the mapping relations between the feedwater flowrate and condensated water flowrate at the deaerator entrance .The model is strongly versatile and easy to be programmed.Furthermore,it effectively avoids the tedious iterative process in the recommendation methods by ASME PTC6 standard and is conveniently applied to the performance test calculation of steam turbines.
Aiming at the flow characteristics of DEH flow path retrofitting for No.3 and No.4 unit of Fengcheng Power Plant,the debugging technology is analyzed combined with the position feedback of linear variable differential transformer(LVDT) during the commissioning operation of units.Furthermore,the feasible solutions are proposed for the problems occurring in the locale construction.
During the startup and operation of SIEMENS V94.3A gas-steam combined cycle unit in Xiaoshan power plant, the unit frequently tripped due to drum water level protection. Based on the mechanism of drum water level fluctuation, the root causes for the trip are analyzed in thermal system design, such as water level control system, high & medium pressure bypass system, as well as selection of the feed water pump. As a result, the bypass control is optimized by controlling load speed, and setting the minimum pressure of the intermediate pressure bypass and attemperating function of the high pressure bypass. In addition, the feedwater control is also optimized for successfully control the drum water level. After the optimization, great effect has been achieved and operational reliability in the control system of drum water level is enhanced.
The basic principle of measuring water level of high-pressure(HP) heater and the method for finding measurment deviation of different instruments are introduced in 1 000 MW units of Huaneng Yuhuan Power Plant.The reasons of why the measurement deviation occuring of the magnetic-flap and pressure-difference water-level meter are analyzed.Furthermore,the problems of water-level measurement existed in barrel,installation and maintainance are pointed out.A new method for assistant determination of water-level measuring locations is presented,where the temperature gradient of barrel surface is measured by infrared thermometer and thermal mapper.The suggestions for treating measured deviation of the water level are discussed,providing references to the installation,trouble shooting,operation and maintenance of water-level measurement of HP heater in power plants.
The test for chemical composition,room temperature and 600 ℃ tensile test,impact property,fracture characteristics and hardness testing are implemented in the sampling P92 steel tube operating 16 000 h in ultra-supercritical units of Huaneng Yuhuan Thermal Power Plant.It is shown that the room temperature tensile strength and the specified non-proportionally tensile strength of the steel tube can reach to 703 MPa and 543 MPa respectively.The non-proportionally tensile strength at 600 ℃ high temperature can meet to the specified commands.The impact energy absorbed is more than 160 J and the impact toughness decreases little.The fracture of the impact sample macroscopically characterizes as tough fracture.The precipitated phase is mainly composed by M23C6 carbide,MX phase and Laves phase of Fe2W type.
This study aims to analyze the problems occurring in the operation of cooling water system in the No.3 units of Chaozhou Power Plant.The suggestions to optimize the system are proposed,including keeping the system rigorous,adopting the condensation water of high speed mixed bed outlet as supplement water during normal operation,and shutting down the sampling gate except for sampling in order to reduce water consumption and maintain the system stability.
In order to avoid the insulating oil overflowing from the segregator and condensator and damaging the vacuum pump,the ABB vacuum oil filter must be closed and the overflowed oil cleared when reaching to the highest point.Then the machine is re-started and put into work.It is bound to affect the efficiency of the oil disposal.Aiming at the problem,the ABB vacuum oil filter is improved by assembling a small drainage equipment below the segregator and condensator.When the oil is overflowed,it is discharged from the segregator and condensator by the drainage equipment,guaranteeing the vacuum oil filter working uninterruptedly.The feasibility and higher efficiency of the improvement is proved by the practice in Nanyang UHV switching station.
The transmission project between Zhoushan and mainland need to cross international navigational route,of which the stringing and construction should have no effect on the navigation.After putting through a primary leading rope,the leading ropes and pulling ropes remained need to be completed by stretch switching and aerial transfer technology.Therefore,the aerial transfer,methods,procedures and operational requirements are introduced for the leading and pulling ropes crossing the tower.
According to the features of large crossing of stain-tangent-strain style at Heiyanzi of the Yangzi River,the catenary control method is applied,by which sub-conductor sags are observed and the removed-length is calculated by ground marking.It is shown from the repetition measurement of assembled-conductor sags that the sag measurement and the secant calculation method are efficient for the conductor sag and sub-conductor errors meeting the demands of design requirements.
In the paper,the argon concentrations are measured by argon gas analyzer during the weldings of high alloy steel,such as stainless steel,martensite steel and etc,of which the effect on weld internal quality is discussed.It is shown from the experiments that the argon concentration in the pipes has significant effect on root protection of weld,which is critical to welding quality.
In the paper,the design of the temporary flushing pipes for 1 000 MW ultra super-critical unit boiler in Huaneng Shantou Haimen Power Plant is introduced.The impact factors considered for the design,such as thermal stress,performance compensation and thermal expansion etc.，are discussed,providing reference for similar design of coal or gas fired units.
