Vol 51, No 4 (2017)

The developed technology of producing cements with biocidal properties and the results of investigating the physico-mechanical properties of the developed cements, cement pastes, and hardened composites are given. Data on the biostability of composites modified with sodium sulfate, sodium fluoride, and polyhexamethylene stearate are presented. Recommended biocidal binder compositions for manufacturing concretes and other cement composites are given.

The article presents the results of investigating the composition, properties, and possibility of using the ash-slag mixture from the combined central heating and power plant No. 9 of the JSC Irkutskenergo as a siliceous component for the production of autoclaved aerated concrete. The composition of density grade D500 aerated concrete is selected. The developed composition and technology of producing aerated concrete were introduced at one of the enterprises in the city of Angarsk.

The dynamic behavior of the thermal-cryogenic regime of the hydrosystem of the Vilyui Hydroelectric Power Plant, which was the first to be constructed in a continuous space of permafrost rock, is presented. Features of the evolution of the thermal-moisture regime of the hydrosystem and the role of rockfill in thermal and mass transfer (crogenic) processes in the artificially created combined natural and engineered system are considered. It is established that, despite more than a 50-period of service, the thermal regime of the hydrosystem is in a fixed state and far from the steady state. Thawing of the shoreline abutments of the dam and in the reservoir floor is observed, and it is noted that the thermocryogenic processes seen in the lower rockfill retaining prism and at the base of the dam are both cyclic. The stability indicators of the hydrosystem are within the standards defined by Russian legislative documents.

Atechnique is proposed that makes it possible to solve the problem of determining the filtration coefficient of a rock mass used as the base of hydroconstructions. The basic data for calculation are the parameters of a network of cracks in the mass and the filtration coefficient of the crack filler. In view of the anisotropy created by the network of cracks, the main characteristic of water penetration is the permeability tensor. The authors’ technique is applicable for evaluating slightly wet rock masses and is in a class by itself in determining water penetration of permafrost rock masses.

The effect of restricting the rate of change of water level in a reservoir on the main energy and financial indicators of a hydroelectric power plant (HEPP) is examined, using the example of PJSC Krasnoyarsk HEPP. These restrictions were introduced depending on the temperature state of the hydraulic structure for the previous period. The calculations that are presented reflect the relative parameters of decreasing the main readings of the HEPP. A quantitative assessment of the decreasing revenue of the company is performed.

Results of mathematical modeling of the burner torch of the furnaces of steam boilers with radiating cylindrical gas volumes are presented. As a result of modeling it is established that with a short torch tongue, the heat flows to the burner device can be significant and the service life of the burners reduced. By means of calculations it is established that with a 1.5 – 2-fold increase in the length of the torch tongue at constant power, heat flow decreases 2 – 3-fold in the burner device and the useful life of the latter increases to 10 years and more.

The results of studying design causes of malfunctions of the thermal-expansion system (TES) in steam turbines are presented. Simulation is performed to show the effect of the clearances in the keyed joints on the probability of bearing seizure in the longitudinal keys. Possible contacts between the longitudinal key and the groove in the bearing are considered. It is proved that the increase in the clearances in transverse keyed joints during turbine operation increases the probability of seizure. For reliable operation of the TES, it is necessary to restore the clearances during each overhaul.

This examines the issue of operability of PLC channels organized on 110 – 750 kV OHLs on which protective devices (PD) against lightning strikes are used in the form of overvoltage limiters and/or discharge devices. It is shown that the operation of PDs can under certain circumstances cause excessive disconnect of the line by phase-differential protection or directed protection during a short circuit on adjacent overhead lines (OHL), or passing an RP and/or EA command transferred on the PLC channel’s DTESC. A conclusion is drawn regarding the necessity of setting up special work for more detailed consideration of the specified issue.

The results of studying the effect of saturation of class P current transformers (CT) in transient modes for actuating the impedance relay of the first stages of remote protection against single-phase short circuits are presented. Various connection configurations of the CT to the resistance relay are examined. Methods of increasing the selectivity and speed of action of the specified protections in the modes under study are substantiated.