Vol 51, No 6 (2018)

The authors have collected publications devoted to field observations of dams, and compared the results with field data of the Nurek HEPP in order to assess the quality of dam construction in comparison with other dams built in the USSR and abroad.

Results of hydraulic studies of a Venturi flume are presented. A method is proposed for calculation of the flume flow rate, with error less than 1%. The proposed method of calculation is compared to the method according to the regulations of the State Standard of the Russian Federation MI 2406–97.

The conditions of power control of the hydraulic generating units of pumped-storage hydroelectric power stations with the use of the capabilities of asynchronized synchronous motor generators are considered. Characteristics that relate the size of the permissible surge in load in emergency control with limitations on the permissible deviation of the rotational speed of the hydroelectric generating units are obtained.

The results of combined geotechnical and geophysical studies of compacted rubble-clayey soil conducted on an experimental embankment for the purpose of developing a seismoacoustic method of quality control of the placement of this soil in a dam body are presented. Recommendations on determining the soil parameters being inspected are given.

A new approach to evaluating the strength of ice in plane stress state is presented. The analytical solution and its graphical interpretation are obtained.

An improved turning apparatus for channels with rapid flow is proposed. A description of a laboratory flume and model of the turning apparatus are presented. Graphical relations of the depths of the flow behind a bend in five transverse sections along four verticals are constructed as a result of hydraulic studies of the model of the turning apparatus. Results of investigations of the velocity structure of the flow in the apparatus are presented. Graphs of the variation of the relative velocities vav/v0 of the flow beyond the apparatus are constructed. The results of the investigations confirm the effectiveness of the improved turning apparatus for channels with rapid flow.

The present article is the first of a series of articles concerned with computational studies on optimization of the process of combustion of a fuel air mixture with temperatures of the gases at the exit from the combustion chamber of around 1600°C where the emission requirements are satisfied. Results of calculations of the combustion of an ideally mixed fuel air mixture in a combustion chamber of typical design possessing several flame stabilization zones formed by swirling of the flows of two swirl nozzles and sudden expansion of the flow in the space of a flue tube are presented. The influence of the position and form of the flame, the concentration and the different variants in which the fuel air mixture is fed into the combustion chamber, the input temperature, preheating in the combustion chamber, swirling of the flow, occupation time, and the pressure and mass of the recirculated flow on the formation of nitric oxides and the completeness of combustion is investigated. Dependences of NO_x emission on different influencing factors are obtained. Using the results obtained we are able to estimate the minimally possible level of nitric oxide emissions attainable with a standard optimized design of single-zone combustion of an ideally mixed fuel air mixture. A further decrease in NO_x emissions is possible through the creation of two or more sequential zones of fuel afterburning in a depleted oxygen-based oxidant. The form and position of the front of the flame and the completeness and length of combustion of the fuel as a function of the above factors, enabled by varying the design of the combustion chamber while maintaining stable and complete combustion of the fuel, are investigated.

Fundamental solutions for improvement of the hydraulic section of the control system for the PJSC “Turboatom” K-300-240 turbine, which is equipped with a standard electronic part of the control system from JSC “Interavtomatika.” Results from tests and normal operation are presented.

Specifics of the distributed networks with auxiliary low-power generating facilities consist in electrical proximity of the generating units (GU) and consumer electrical receivers, which, therefore, share the transient processes, while the parameters of such processes heavily depend on both GU and load parameters. This paper provides the results of analysis of the challenging technical issues associated with the GU integration into such networks with respect to selection of the relay protection and automatic equipment.

An assessment of sensitivity of the measuring elements of relay protection was performed. Based on simple examples of the generator-transformer unit protection from symmetrical short circuits, it was shown that the sensitivity factor is not a sufficiently objective measure of sensitivity of the relay protection. It was suggested to use a more objective measure, which is a characteristic of sensitivity to transient resistance at the fault location (dependence of the transient resistance, at which the protection stops tripping, on the fault location).

The main advantages and disadvantages of single- and twin-shaft CCPPs are analyzed, taking into account various configurations and thermal efficiency and controllability. Single-shaft configurations with and without freewheeling clutch between the electric generator and the steam turbine are considered. Single-shaft 370 – 420 MW CCPPs operated in Russia are compared with twin-shaft units of the same capacity.

The electrical consumption schedules and the structure of the installed power of the Unified Power System (EES) of Russia are examined. The operating costs of nuclear power plants compared to combined cycle (steam-gas) plants as a function of the depth of nighttime unloading at different times in the fuel campaign of nuclear power plants are calculated. It is shown that running nuclear power plants with variable loading is economically unfavorable compared to unloading of combined cycle plants; in addition, at the end of a campaign, the unloading of a nuclear power plant is limited and requires deeper unloading of the unit all the way to stoppage, which leads to greater system costs.