With the gradual increase of peak-valley difference of grid load, many types of equipment of power generation, transmission and distribution should be added or retrofitted to meet the peak load demand for electricity. While the low loading rate of grid may lead to a lower asset utilization ratio of power equipment, which makes power planning and construction less economic. Energy storage technology can solve the problem of increase of peak-valley difference and low asset utilization ratio, however, the high cost of the energy storage system limits its large-scale applications at present. Considering the charge-discharge balance constraints and cycle life of energy storage system, the control strategy of energy storage technologies for grid peak load shifting is studied, and the mathematical model is established for the economic evaluation of investment in the energy storage system. Taking actual load data as examples, the capacity demands of energy storage system under different peaking degrees are simulated and analyzed. The economic issues of energy storage system investment are studied from the view of social benefits and investors respectively. Finally, the economic conditions of large-scale applications of energy storage system are proposed.
There are many uncertainties in the power system, which have profound significance on the evaluation of lines’ priority. With the application of fuzzy set theory, the fuzzy calculation method of power flow after line returned is proposed, by taking generator output and load uncertainties into account. The generator output, generator availability and load uncertainties are described by the trapezoidal fuzzy numbers. Combined with the sensitivity-based approach of the existing fast algorithm, the possible flow distribution after the line returned is obtained. Then the necessity of considering the uncertainties in the analysis of the system state when line returned and the value of the approach introduced in this paper are verified. Finally, the calculation result of IEEE-30 bus system is provided.
In order to propose an anti-typhoon design method suitable for China’s national conditions, this paper firstly introduces the basic characteristics of typhoon such as strong extreme wind speed, prominent non-stationary, quick change in wind direction and synchronization with huge waves. Then common failure modes of offshore wind turbines under typhoon are analyzed, including overall overturning, tower failure and blade damage. Based on this，the design concepts of anti-typhoon are explored, which suggested that the subversive failures should be prevented and the anti-typhoon design based on reliability should be adopted. Furthermore, some anti-typhoon measures are proposed, such as vibration control technology and concrete wind turbine tower, which provide references for the anti-typhoon design of offshore wind turbine in China.
According to the characteristics of power distribution network, the evaluation contents of the evaluation system for power distribution network are proposed. According to differentiation principle, evaluation standards of different indices are determined. Then, the practical calculation method for the scores of evaluation indices is given through the classification on evaluation indices based on its properties. Finally, with the application of evaluation process described in this paper, present situation of distribution network in a region is evaluated, which could verify the validity of the method.
High-voltage electric equipment in substation has high vulnerability during earthquakes. In order to investigate the applicability of isolation technology in UHV electric equipments, two finite element models of 1 000 kV arrester with and without isolation layer are established by ANSYS. And the dynamic time-history analysis using these two models are carried out by inputting earthquake waves. The results show that the arrester with base isolation has lower frequency. And its top displacement response, acceleration response, bending stress of porcelain bushings all have different degrees of reduction compared to those of arrester without base isolation. These conclusions have verified the effectiveness of the isolation system, and have provided a basis for the practical application of isolation technology in UHV electric equipments.
The 1 000 kV structural gantry is a high and heavy load steel latticed structure, which is of vital importance in the 1 000 kV electric substation. The 1 000 kV structural gantry is a tall and slender structure and of high natural vibration period, therefore, its dynamic response under the action of wind load is very significant. This paper describes the simulation of the fluctuating wind speed in atmospheric boundary layer in Matlab by adapting the Davenport spectrum. The 1 000 kV structural gantry’s wind-induced response is analyzed in Ansys software on the premise that the wind is loaded on the structure. Then the wind-induced vibration coefficient is calculated on each subsection of the 1 000 kV structural gantry and compared with the design value based on the related regulations. The calculation results show that the wind-induced response of the 1 000 kV structural gantry in x direction is not exactly the same as that in y direction. The wind-induced vibration coefficient, which is obtained from the theoretical calculation, is not proportional to the height. The x direction wind-induced vibration coefficient mutated at the cross beam position. The member force calculation indicates that it is feasible to use a unified wind-induced vibration coefficient along the latticed section’s full height in the design of 1 000 kV structural gantry. The result is not different from the member force calculation based on the actual wind-induced vibration coefficient on each subsection.
At present, allowable values of voltage in dangerous effect and longitudinal electromotive force in interference effect are practically uncertain in the anti-interference design of DC power transmission line for local telephone system. According to the interference principle, national and international standards and latest research results, standardized suggestions are promoted, which could provide the basis for compiling power industry standard DL/T5340: “Technical Code for the Design of Telecommunication Lines Against Danger Effects from DC Power Transmission Lines.”
The deficiency of current steady state data monitoring in electric power system is analyzed in this paper, and the integration system scheme based on network protection and the panoramic data platform scheme used in this system are introduced. The system was changed from the traditional four layers structure into three layers: process layer, equipment layer and control layer. According to different areas, a distributed real-time database is proposed in panoramic data platform, and a storage scheme is also suggested for mass data. Then, the new characteristics of steady state data in the new system is analyzed, as well as a new way of data organization and simplified operation process are presented based on the information characteristics of the same section steady-state data monitoring. Finally, through the application the new scheme is verified to have the quite big advantage in solving the current problems.
The smart substation changes the construction mode of traditional substation, in which the optical fiber cable becomes the main medium for communication because of its network. The existing connecting way of outdoor optical fiber cable has many disadvantages and can not satisfy the need of smart substation development. A solution based on prefab optical fiber cable for the outdoor network is proposed, which had been successfully applied to practical project and could efficiently improve the security, reliability and stability of network communication in substation. This solution has many advantages, such as simple structure, convenient construction, safety, durable use. It can greatly shorten the construction period and improve the fault resistance ability of smart substation, with increasing a little investment.
The key technology of sharing modeling between dispatch center and substation which is based on standards IEC 61850 and IEC 61970, contains two aspects: the pattern generation standard from substation to dispatch center, and the reduction of model and graphics for substation required by dispatch monitoring control center. Through the research of this key technology, the sharing modeling between dispatch centre and substation could become practical.
The development process and research status of micro grid are reviewed, and its characteristics are analyzed in this paper. Furthermore, some key technologies of micro grid construction in island are discussed based on the energy demand in islands. Finally, the guiding ideology of micro grid construction in remote islands, and the technological route of micro grid in islands which would be adapted to the practice situation of China are suggested, as well as the software for the design of micro grid and some suitable products are developed.
At present, there are several application examples of distributed energy system in China, which can provide flexible supply of energy, but have some shortcomings such as low operation efficiency, poor economic performance and so on. In order to improve the primary energy ratio of distributed energy system, a demonstration project of efficient combined cooling and power system using natural gas has been built, which relied on three buildings located at the Foshan Power Supply Bureau. According to the problems of low primary energy ratio and backpressure of gas turbine exhaust over the limit in demonstration project, the transformations were carried out for the main engine and coherent system. The results show that the annual primary energy ratio of distributed energy system depends on four aspects of factors: the efficiency of main equipment, the waste heat utilization of flue gas, the equipment load and the operation time per year.
Taking No.3 and No.4 units in Tianwan Nuclear Power Plant as examples, a simulation using ETAP software was performed on auxiliary power system, according to the four kinds of transient condition requirements proposed by Russian design institute. The simulation results show that the design of auxiliary power connection scheme can meet the requirements for power transient stability put forward by Russian party. The ETAP analysis report on transient stability has obtained a unanimous approval of the general designer and the owner. And the simulation results has filled the design gaps in electrical transient analysis for nuclear power plant in China, realizing a progress from static estimation to transient stability simulation.
The smaller pulverized coal fineness is better for the ignition and burnout of coal. And the fineness of pulverized coal directly influences the content of combustible in fly ash and slag. In order to solve the operation problems in Shanxi Xingneng Power Plant, such as slag dropping form dry slag machine, high slag temperature, the outage of slag crusher, and so on, adjustment tests of pulverized coal fineness were carried out for the mill. For example, by adjusting the separator speed of mill to change the fineness of pulverized coal; through keeping the oxygen steady at the furnace outlet to study the influence of pulverized coal fineness on the content of combustible in fly ash and slag, as well as the thermal efficiency of boiler. All these tests could provide a basis for the adjustment of rotary separator in medium speed mill. The results show that when the coal finess controlled within 17% and the evenness index of pulverized coal reaches 1.20, the coarse particles in pulverized coal significantly decrease which is beneficial to coal burnout. After the adjustment of pulverized coal fineness, the amount and temperature of slag decrease, which has improved the safety and economy of units.
The voltage level and capacity of the temporary excitation power should be correctly choosed and the protection setting for the safe and smooth first-starting of units should be calculated. According to the starting test of No.1 unit in a power plant, in this paperthe selection of excitation power and the calculation of the protection setting for the self-shunt units are discussed, and the generation mechanism of magnetizing inrush current is analyzed in the case of non-full voltage impaction on excitation transformer. The results show that the magnetizing inrush current generated by non-full voltage impaction is far less than that by full voltage impaction, which is totally different from the magnetizing inrush current generated by the transformer no-load closing with nominal voltage, and is verified by the incident wave records. On that basis, combined with the incident instance, the conclusion that the large protection setting values for excitation temporary source could cause the protection failure under short circuit conditions of excitation transformer at the low voltage side is pointed out, and a correct protection setting value method for temporary relay is suggested, which could meet the requirements of starting test.
According to the geological characteristics of construction site, the treatment schemes for two types of cooling tower foundation are compared, and the reinforced concrete (RC) pile foundation is selected. Then, the technical and economic comparisons are implemented on several pile foundation schemes with different pile diameters (0.8 m and 1.2 m) and pile layout, by using TSH3SCOQ static calculation program (moment theory) for hyperbolic natural draft cooling tower. Finally, a reasonable and economic design scheme of pile foundation is determined, in which six bored piles whose diameters are 12 m are arranged under each pair of X pillar.
As a core of selective catalytic reduction (SCR) De-NOx device, catalysts play a key role in the operation of De-NOx device. The catalysts are easily blocked because of the high and unstable ash in flue gas in domestic coal-fired units. The harmful substance in flue gas, such as arsenic, alkaline, etc., could lead to the deactivation of catalysts due to the chemical poisoning. These problems could be well solved when plate-type catalysts were used due to their special structure (big opening ratio) and processing technology (using flexible stainless steel meshes as carrier and MoO3 as promoter). With catalyst performance stability as the standard, the advantages of plate-type catalysts in coal-fired units from the aspects of blocking, coverage, abrasion, and chemical poisoning are discussed in this paper.
According to the structure and erection method features of 500 kV triple circuit tower, a mixed suspension gin pole with rotatable-seating double-rocker and outside guy wire has been developed. If the hoisting of the lower part of triple circuit tower has the feature of big root distance, heavy weight and high requirement of hoisting operation, the gin pole can choose seating-type and double rockers; if the hoisting of the upper part of triple circuit tower has the feature of small root distance, relatively light weight and low requirement of hoisting operation, the gin pole can be changed to suspension type.
In order to effectively solve the problems of tension composite insulator applied in 750 kV transmission lines, some measures are proposed in this paper, such as the optimization of umbrella-type tension composite insulator, the protection of the mandrel against brittle fracture, and the protection of tension composite insulator in construction and operation. These measures could make 750 kV transmission lines avoid the tremendous impact of the pollution flashover and ensure the safe and stable operation of 750 kV transmission lines.
The industrialization management of project design for nuclear power plants is very mature at abroad, while this work in China has just started. Withintroducing the features of foreign design industrialization management in this paper, the industrialization management of pipeline design for nuclear power plants adapted to China is proposed, including the design stage division and design control. Through the analysis of the efficiency and cost of industrialization management for pipeline design, the labor cost with the management pattern of industrialized thinning division is much smaller than that using the normal management pattern.
