


Том 52, № 3 (2018)
- Жылы: 2018
- Мақалалар: 21
- URL: https://journals.rcsi.science/1570-145X/issue/view/15327
Hydrotechnical Construction
Special Operations to Stabilize the Powerhouse of the Zagorsk PSPP-2
Аннотация
A work package for filling the voids under the pumped-storage powerhouse and pressure grouting to strengthen the foundation soil is described. The compositions of the injectable grouts and specially designed composite material are presented. The results are analyzed.



Article
Analysis of the Resonance Phenomena in the Operation of the Lower Bureya HPP During an Earthquake
Аннотация
To justify that hydroelectric power plants operating in seismic areas are safe, it is necessary to analyze the resonance phenomena in the generating unit. The analysis was performed using a finite-element model of the powerhouse-foundation-equipment system of the Lower Bureya HPP. The resonance phenomena occurring when the disturbance frequency at the elevation of the stator supports is close to the first natural frequency and speed of the water turbine were studied.



Influence of Irregularities of Water Vapor Field in Surface Layer of the Atmosphere on the Results of Satellite Monitoring of Hydropower Structures in Region of Reservoirs
Аннотация
Results are presented for the modeling of coordinate errors in the projected GNSS system of monitoring the Zagorsk GAES-2 that are caused by local atmospheric irregularities in the surface layer. It has been established that for mean meteorological conditions, these errors can reach 0.8 mm for elevation and 0.1 mm for horizontal position. It is noted that actual instantaneous irregularities exceed mean values by an order of magnitude and can thus cause larger errors in coordinates.



Radar Remote Method of High-Precision Monitoring of the Geodetic Alignment and Natural Oscillations of Dams
Аннотация
The article examines problems of real-time remote monitoring of the geometric form of the upper alignment and natural frequencies of oscillations of a dam using a radiogeodetic method with accuracy to ± 1 mm from a distance up to 1000 m. At the foundation of the method is the use of active radar and miniature switched re-radiators in the form of slot antennas located in a linear row along the top edge of a dam. By contrast with the method of telemetry that uses high-precision optical devices — tachometers, levelers, etc. — the radiogeodetic method can be executed in real time with minimum effect from weather conditions.



Filtrating Outlet Works for Rockfill Dams
Аннотация
A brief history is provided of the application of filtrating outlet works in Russia. Primary attention is given to the discharge rate of filtrating outlet works on rockfill dams with ferro-concrete and asphaltic-concrete upstream membranes. A formula is given for determining the discharge rate of filtrating outlet works and recommendations are given for accounting for the effect of the filtration stream on the design of rockfill dams.



Some Lessons Learned from On-Site Observations on High Concrete Dams
Аннотация
Some results of generalizing and analyzing long-term on-site observations of the construction and operation of high-head concrete dams with consideration of geodynamic effect and imperfection of the designs of dams in tectonically unstable regions are briefly presented.



Improvement of Cascade Regulation of River Flow of Reservoirs
Аннотация
The article is devoted to the problem of imperfect regulation of river flow in a cascade of reservoirs exemplified by the Kama and Votkinsk hydroelectric power complexes. The reservoir filling and emptying storage-outflow curve makes it possible to increase the regulating capacity of the hydro complexes for solving problems of downstream navigation.



Use of Sprayed Concrete in the Construction of Tunnels
Аннотация
Experience gained from sprayed concrete operations in the construction of several tunnels around Sochi and reconstruction of the Kurort Prospekt in the city as well as devices for sprayed concrete reinforcement of open slopes along automobile roadways is described. The compositions of different types of sprayed concrete are given and the strength indicators in the initial periods of hardening are indicated. Certain parts of the production process are demonstrated and practical recommendations presented.



Quality Control of the Stacking of Coarse Fragmental Soil in Test Pits of Reduced Size in the Construction of Dams
Аннотация
The requirements of regulatory documents imposed on the selection of control samples of coarse fragmental material often hamper the rate of erection of earth and rockfill dams and complicate operational assessment of work quality. Through the evaluation of the possibility of quality control of the stacking of coarse fragmental material in pits of reduced size by controlling the density of all the soil material relative to the density of fractions 200 mm, similar to the determination of the entire soil density relative to the density of fine material (5 mm), it becomes possible to optimize these types of operations without worsening their quality.



Graphical-and-Analytical Method for Designing Reinforced-Concrete Scroll Casings of Water Turbines Based on Laws of Variation in Cross-Section Average Tangential Velocities
Аннотация
A new graphical-and-analytical method for design of reinforced-concrete scroll casings with trapezoidal cross-sections of water turbines is proposed. This method generalizes the methods currently used to determine the trapezoidal cross-section dimensions of scroll casings, given the dimensions of their inlet cross-section. This method allows considering different laws of variation in the cross-section average tangential velocity along the scroll length: the velocity can increase, be constant, decrease, or vary differently within different sections of the scroll. The necessary formulas are derived by an analytical method. The design procedure is described by way of examples.



Numerical Modeling Study of the Operation of a Dynamic Dust Separator
Аннотация
The development and testing of a computational model for a dynamic dust separator based on the ANSYS-Fluent program package are discussed. The numerical simulations are in good agreement with experimental data obtained on a commercial separator. The operation of the dynamic separator with bituminous coal is studied numerically over a wide range of parameters. The hydrodynamic features of the apparatus and the effect of its design on the fuel separation process are clarified.



Analysis of the Efficiency of Using the Heat of Natural Gas Combustion Products to Preheat Forced Air Supplied to the Boiler
Аннотация
Preheating of forced air in a surface-type heat exchanger prior to supplying it to the air heater of the boiler by using flue gases while cooling them below the dew point is proposed. Athermal calculation of the condensing heat exchanger installed downstream of the boiler (model BKZ-420-140 NGM) was performed to determine the thermal capacity of the heat exchanger, flow rate of flue gases required to preheat forced air supplied to the boiler while cooling them below the dew point, flow rate of the water vapor condensate obtained from the gaseous fuel combustion products, temperature of flue gases at the outlet of the boiler unit, and fuel utilization factor of the boiler resulting from the use of the condensing heat exchanger. The water vapor condensate obtained from flue gases in the surface heat exchanger can be used as make-up water for the heat network. It was established that depending on the ambient air temperature, the percentage of flue gases directed to the heat exchanger for preheating forced air of the BKZ-420-140 NGM boiler assuming their cooldown below the dew point constitutes 3.9 to 20.7 and 7.6 to 24.4% of their total amount, when heating air to 20 and 30°C, respectively. The economic effect in the monetary terms due to installation of the condensing heat exchanger downstream of the BKZ-420-140 NGM boiler amounts to 12, 691.7 and 17,242.2 thousand RUB/year, when heating forced air to 20 and 30°C, respectively. Considering five power-plant boilers installed at the Samara CHP operated by “Samarsky” branch of the PJSC “T Plus,” the amount of savings should reach 63.5 and 86.2 million RUB/year, respectively.



Justifying the Vibration Resistance of Pipelines of NPPS
Аннотация
The NP-096-15 regulations require the design documentation for NPP pipelines to justify life characteristics and life evaluation criteria and to provide monitoring of such characteristics of pipelines during their entire service life. A review of strength design regulations regarding the justification of the vibration resistance of NPP pipelines shows that the evaluation of their damage is based on a limited spectrum of dynamic stress amplitudes, which affects the accuracy of the evaluation of cyclic strength. Amethodological approach to the justification of the vibration resistance of pipelines is developed and tested in industrial conditions. The approach is based on a stress-based failure criterion and a mathematical model describing the vibrations of pipelines with allowance made for the effect of the flow on the wall based on the local isotropic theory of turbulence.



Development and Study of the Start-Up Sequence for E-240-13.8-560 Solid-Fuel-Fired Boiler by the Zio Company
Аннотация
The results of the development and study of the start-up sequence for an E-240-13.8-560KT steam boiler are presented. Criteria of reliable operation of boiler components during start-up are proposed. The change in the main operating conditions of the boiler during start-up is described. The use of emergency start-up injection is justified. The effect of the wall thickness of the drum on the start-up of the boiler is analyzed.



Evaluation of the Long-Term Operating Life of Chromium-Molybdenum-Vanadium Steel Components with Respect to Micro-Damage
Аннотация
Stress-rupture strength tests are performed and metal micro-damage is studied in an electron microscope for a body made of chromium-molybdenum-vanadium steel 15Kh1M1FL with a long (331,000 h) running time. Dependences are found for metal endurance on relative integrity, and images are given for different scale points of micro-damage. On the basis of conformity of damaging effects on the life of fixed values of integrity and micro-damage scale points residual life factoors are determined for the main points of the scale.



Experience of Using Steel DI59 for Manufacturing Boiler Superheaters
Аннотация
Favourable experience is summarized for manufacturing, welding, storage, and operation of superheaters made of heat-resistant chromium-manganese steel DI59, and a mechanism is described for overall corrosion breakdown and oxidation over pipe metal grain boundaries under action of active components fuel combustion products of V2O5 and sulfur compounds.



Selection of a Circuit of a Transversely Connected Active Filter with Compensation Function for Short-Term Voltage Interruptions
Аннотация
The article examines circuits of modular multilevel converters, which show promise for the creation of an active filter with the functions of compensation for a reactive load current, its balancing, filtration of the highest harmonic currents, and short-term power supply load in automatic reclosing (AR) dead time. Circuits for distributed and concentrated connection of an energy storage unit based on supercapacitors are compared. It is shown that a circuit with a concentrated storage system is preferable, due to the simpler method of increasing storage system capacitance and the lower power consumption of the storage systems.



Calculation of the Admissible Short Circuit Current for the Protected Wires of an OHL
Аннотация
Polymer materials used in protected wires are very sensitive to the temperature increase that occurs in the course of a short circuit (SC) current. Heating the insulation of the wire above the admissible temperature for it may make it necessary to replace the damaged wires. A methodology is proposed for calculating the admissible SC current for the protected wires of an OHL, taking into account the periodic and aperiodic components of the SC current. The materials of this article can be used in designing and using lines made with protected wires.



Thermal Stability of Overhead Power Transmission Lines Under Growing Short-Circuit Current Levels
Аннотация
Since early 2000s, an increase in the levels of short-circuit (SC) currents has been observed within the electric power systems of the Russian Federation, including 110 and 220 kV networks. This problem is especially important in the regions with high density of electric power plants and relatively short distances between network nodes. As the level of short-circuit currents increases, the issues of thermal and electrodynamic stability of the electrical equipment, and first of all, equipment which has completed its standard service life, become of primary importance. The paper discusses the issues of thermal stability of the overhead power transmission lines (OPTL), offers analysis of the calculation results related to wire heating by SC currents in more than 1000 OPTL operating at 35 – 220 kV of voltage, and provides recommendations for ensuring thermal stability of OPTL.



Thermal Power Plants
Application of the Technology of Combustion of Solid Fuels in a Circulating Fluidized Bed
Аннотация
It is shown that the basic variations in the energy market are related to increasing requirements designed to assure ecological cleanliness as well as increase efficiency, reliability, and maneuverability. The ability of the technology underlying the combustion of solid fuels in a circulating fluidized bed to respond to these variations is demonstrated using concrete examples. It is noted that the efficiency of the circulating fluidized bed technology is determined basically by the quality of the fuel and the capacity of the power station with specified constraints imposed on discharges of harmful substances. Attainment not only of the norms on harmful substances existing in the Russian Federation, but also of prospective norms without the use of desulfurization and denitrogenization devices, is an important condition for optimal use of the technology. Another major advantage is the diversification of fuel deliveries. The first boiler in Russia employing a circulating fluidized bed was built at Unit No. 9 of a condenser type electricity-only thermal power station (GRES) at Novocherkassk, Rostov oblast’. Delivery of the boiler was performed by the firm of JSC EMAl’yans Inzhiniring while delivery of certain critical parts and auxiliary equipment, by the firm of Amec Foster Wheeler (now Sumitomo Foster Wheeler, or SFW). The first results of the operation of a circulating fluidized bed boiler are presented and an analysis of trial data on the thermal balance of the heating surfaces is presented. In the case of similar values of the trial and design heat absorption of the boiler guard screens, the temperature of the gases in the boiler is substantially higher than the design temperatures. Certain difficulties associated with the technology of combustion are identified in the process of adjustment and early use of the circulating fluidized bed boiler in Unit No. 9 of the Novocherkassk GRES. The need for a more detailed study of the processes involved in production of additional measurements and of studies on operational development of the equipment and thermal circuit, and optimization of the operating conditions is demonstrated.



Power Systems and Electric Networks
Prevention of Overcurrent and Admissible Voltage Limit Violation in Electrical Network Nodes
Аннотация
In a centralized emergency control system (CECS) with a third-generation algorithm, emergency control actions (CA) are selected under conditions of preventing disruption of dynamic stability, providing the required margin of stability in post-emergency condition, as well as preventing overcurrent and restricting voltage in network nodes to admissible limits. A methodology for selecting CAs for these last two conditions is described.


