Vol 53, No 2 (2019)

A technology for geodetic monitoring of the displacements of hydropower structures during compensation grouting has been developed. Recommendations are provided for optimal composition, configuration, and functional structure of automated geodetic monitoring systems based on robotized tachymeters. The process of handling and analyzing data is shown using the example of the system of monitoring the uplift of structures of the experimental ground of Zagorsk GAÉS-2. Separate attention is given to visualization of monitoring results.

Resistance in sheet piling joints during pile driving affects the quality of performance of the work. The probable resistance forces in of the “cam in iron ring” joint type were studied on the basis of analysis of the operating set of documentation and of tests.

A FEM method for and the results of solving the coupled static and seepage problems for a concrete gravity dam on a block rock foundation are presented. The change in the permeability of the foundation due to the opening of cracks and joints and subdrainage is taken into account.

The state of the art in the protection of the bottom near and the foundations of hydraulic structures from scour caused by marine propulsors is analyzed. The need to formulate recommendations on determining the parameters of the scouring action and engineering measures to protect the bottom against scour is identified.

The feasibility of assembling and maintaining complex and expensive automatic equipment for navigation locks is considered. The hydraulic structures, including the hydraulic component of the locks, represent a stable system designed to function reliably for many decades. From the point of view of the present authors, a prediction of their state may be carried out by professional hydraulic engineers without the use of automatic equipment

Examples are given about the protective and rescue measures being taken for wildlife during creation of a water object. Tests of various methods of minimizing the impact on wildlife carried out during filling of the Lower Bureya HPP reservoir in the Amur Oblast are described.

Technology is provided for restoring erosion damaged rotor blades of the last stages of steam turbine low-pressure cylinders (LPC) using laser-powder surfacing and application of an erosion-resistant coating. For this method there is typically low heat input into the blade basic metal, which improves its restoration reliability. Results are obtained for comprehensive experimental studies on specimens and blades, confirming the high quality of welded joints obtained by laser surfacing of nickel alloy proposed for restoring the blade profile of blade steels ÉI961-Sh and 15Kh11MF-Sh, and application of a stellite-6 erosion-resistant coating. The possibility is concluded of using the laser-powder surfacing method during refurbishment of steam turbine LPC rotor blades.

In accordance with the Federal Grid Company (FGC) standard STO 56947007-29.240.55.143-2013, the allowable current in the wires of the overhead power transmission lines shall be determined by considering the intensity of heat transfer between the wire and air. The heat transfer intensity is determined by the Newton – Richman formula and depends on the heat transfer coefficient, which is the main quantitative characteristic of the heat transfer process. This coefficient should become one of the characteristics of the new generation of wires, and especially, high-temperature wires. The paper describes how this coefficient is calculated using one of the new generation wires as an example.

An analysis of the influence of changes in the power industry of Russia as well as throughout the world on the risk of out-of-step conditions accompanied by a qualitative assessment of their negative consequences is presented. The problem of preventing and eliminating out-of-step conditions is greatly complicated today because of large-scale construction and commissioning of distributed electrical generation plants along with the use of modern small-scale generating plants and the development of large industrial plants with their own internal sources of electrical energy. Features in the use of automated devices for eliminating out-of-step conditions under these new conditions are considered. The feasibility of creating an innovative adaptive complex to protect against out-of-step conditions at power engineering plants is evaluated. The basic principles in the construction of an automatic engine for adaptive out-of-step protection with the use of synchronized vector measurement algorithms are presented. The structural and functional designs of an adaptive out-of-step protection complex are presented. Recommendations for the use of an adaptive automatic complex for protection against out-of-step conditions to increase the operating reliability of power plants are presented.

Outages of three-phase motors owing to voltage asymmetries produced by the operation of distant distorted loads are examined. Several ways of solving this problem are examined, including with a phase-controlled static thyristor compensator (STC). A method is proposed for choosing the power of the STC needed for guaranteed compensation of the reverse (negative) sequence voltage taking into account the permissible operating time for three-phase motors with a given reverse sequence voltage level. Algorithms for phase control of STC are proposed and their efficiencies are compared on a test-bed. It is shown that the use of a special algorithm with priority suppression of the negative sequence voltage makes it possible to enhance the efficiency with which the installed STC power is used and to reduce the number of outages of motors caused by protections that are sensitive to the negative sequence voltage.

An assessment of the survivability time was performed for the following two parts made of 10Kh9MFB-Sh steel at 600°C and maximum allowable metal stresses: a pipe measuring 630 mm in diameter and having a wall thickness of 25 mm, and a pipe billet produced by electroslag remelting (ESR) technique. The specific feature of the proposed procedure consists in testing samples containing an extra deep and sharp notch. To determine the time to breaking, the notch opening rate was registered at an increased frequency of 0.003 h. It is shown that metal of the billet produced by the ESR technique has an advantage of longer service life in comparison with the hot-worked pipe. A simplified version of the procedure featuring fixed parameters of the breaking conditions is proposed for the base and weld metal.

The parameters of signals from high-frequency power-line communication equipment and location monitoring equipment transmitted via high-voltage power lines are compared. The results of experiments on the mutual influence of this equipment performed on existing power lines are presented. It is shown that the location monitoring equipment generating pulses that are shorter by three orders of magnitude than those of the high-frequency communication equipment and are of comparable amplitude do not affect the operation of this equipment. The location pulses are reliably discriminated from the high-frequency communication signals using the averaging and spectral analysis methods. The results obtained are confirmed by the stable parallel operation of location monitoring equipment and high-frequency communication equipment for 10 years.