Conversion of the steam-supply system of 800-MW supercritical-pressure units to lower steam temperature upon introduction of a sliding startup process

Results of testing a novel process of startup of 800-MW supercritical-pressure units at sliding pressure in the entire conduit of the once-through boiler with the temperature of extraneous steam in the station-service header supplying the turbine-feeding pump reduced to ∼250°C and intermediate transfer of its feed to its own steam through the available station-service starting-shedding device are given. It is shown that the use of this process makes it possible to fully pass to steam supply of the unit from the colder second extraction of the turbine. A variant of updating the steam feeding circuit is suggested. __________ Translated from élektricheskie Stantsii, No. 11, November 2006, pp. 9–13.     

Modernization of standard and rapid pressure-reducing and cooling units with injection of high pressure water

Operating experience with different standard (ROU) and rapid (BROU) pressure-reducing and cooling units is examined. A scheme for updating standard ROU and BROU steam desuperheaters is proposed which avoids formation of stress concentrations and erosion washout of the parts by eliminating the rigid connection between the feeder element and the injector device: modernization of commercial steam inlet nozzles and injector regulator valves with multistep throttling of the working medium which ensures reliable, long duration operation with water feed from an electrical feed pump. For the modernized version it is proposed that the worm swirler be replaced by a bushing with a tangential fluid feed. Modernization can be done in the repair shops of operating power plants, as well as at the manufacturers' plants. Translated from élektricheskie stantsii, No. 5, May 2008, pp. 9–16.     

Transport of Contaminants with Boiler Water Steam

A method for determining coefficients of distribution of contaminants between boiler water and steam generated in boilers and steam generators of nuclear power plants, which is based on standard thermodynamic dissociation constants, is presented. Appropriate analytical dependences are given for hydroxides of metals used in the power industry for pressures of 40, 87.5, and 155 kgf/cm² (3.9, 8.6, and 15.2 MPa). __________ Translated from Elektricheskie Stantsii, No. 7, July 2005, pp. 38 – 39.     

Ways of solving nitrogen oxide emission problems at thermal electric power plants in Russia

The more than 2000 steam boilers operating at the thermal power stations of Russia can be divided into three groups, taking into account their operating lifetimes and steam parameters, which determine the efficiency with which they produce electrical energy. Given the expected rise in penalties for harmful discharges into the atmosphere, it is proposed that a way of reducing the nitrogen oxide emissions be chosen for each group that will minimize the expenditure for the owners of thermal electric power plants. Translated from élektricheskie Stantsii, No. 11, November 2008, pp. 9–12.     

On the water-chemical regime in steam generators at NPP

The effect of the water-chemical regime (WCR) on damage sustained by heating surfaces of steam generators at NPP is analyzed. It is indicated that phosphate treatment with minimal excesses of phosphates in the steamgenerator water is the most optimal method of managing the WCR regime of horizontal steam generators. __________ Translated from élektricheskie Stantsii, No. 5, pp. 15–21, May, 2006. In order of discussion (The editor).     

Modernizing the boiler installation for unit no. 3 at the Kashirskaya GRÉS to reduce nitrogen oxide emissions

The purpose of modernizing the Pp-1050-25-545 KGZh (P-50R) boiler is to reduce the emissions of nitrogen oxides (NO_x) to levels consistent with modern requirements. The following engineering steps were taken, with liquid slag removal from the boiler, to attain NO_x levels of 700–750 mg/m³ for operation with coal and 125 mg/m³ for operation with natural gas — three-stage combustion with natural gas as the reducing fuel (∼15% thermal) burning in the recirculating gases; and — use of low-emission coal-dust burners with dust feed at high concentrations, overflow burners, and tertiary draft nozzles to lower the amount of excess air in the active combustion zone. The NO_x level was further reduced to 570 g/m³ (just for operation with coal) by using a selective noncatalytic nitrogen oxide reduction system with injection of ammonia (NH₃) vapor into the boiler in a zone with temperatures of 950°C. __________ Translated from élektricheskie Stantsii, No. 1, pp. 2–8 (2008).     

Asynchronous nonsalient-pole compensators with total air cooling1

The fundamental parameters and construction of asynchronous compensators, soon to be produced by the “Silovye Mashiny” — “élektrosila” Joint Stock Company in 2008, are considered. The compensator has a massive nonsalient-pole rotor with two excitation windings, shifted by 90° (in electrical angles), supplied from controlled reversible power sources. The compensators provide delivery-consumption of reactive power in the ±100 Mvar range with the possibility of short-term double forcing of the power output and improved dynamic characteristics compared with synchronous compensators. ¹ This paper is based on material presented at the conference “Russia Power 2008” (Moscow, April 2008). Translated from élektricheskie Stantsii, No. 11, November 2008, pp. 62–65.     

Development of engineering solutions for creation of turbine plant for power unit with supercritical steam parameters

Problems arising in the transition to a new level of steam parameters of power units are considered. The dependence of the efficiency of the unit on the efficiencies of individual turbine stages and different layouts is considered. It is shown that using the experience of best domestic producers the efficiency of a unit can be brought to the level of the best foreign counterparts. __________ Translated from élektricheskie Stantsii, No. 10, October 2005, pp. 36–40.     

Analysis of the development of damage in a welded junction in the hot intermediate superheat steam duct of 800-MW generator units

Data from a metallographic study of a damaged weld junction in a hot intermediate superheat steam duct and a computational model for crack development (in the damaged zone) by a creep mechanism are described. Anumerical calculation confirms the possibility of crack development to the known final size over a time of approximately 15,000 h, which corresponds to the operating time for the steam duct from the last time it was inspected until the time of a through fault, under conditions such that a 2.5-mm-deep surface crack (with a length of ∼50 mm along the surface) had been overlooked during this last inspection. Translated from élektricheskie Stantsii, No. 10, October 2008, pp. 29–35.     

Possible use of feed water for boiler injectors

The operation of steam desuperheaters with injector devices with water supply from condensate equipment in boiler units is analyzed. An analysis is given of articles which demonstrate the feasibility of transferring the regulation of the steam temperature in desuperheaters by the condensate itself to regulation by injection of feed water. Schemes are proposed for supply of feed water with the possibility of using a regulator valve. Schemes involving the installation of hardware in the feed line that ensures the required leak tightness, pressure drop, throttling and flow rate, are examined, and a scheme is proposed for modernization of startup injection. Translated from élektricheskie Stantsii, No. 8, August 2008, pp. 17–24.     

Lowering the erosion wear of long blades of the last stages by optimum hanging

Problems of optimum hanging of long rotor blades of the last stages of steam turbines are considered. Causes of nonuniform erosion wear of the inlet edges connected with inaccurate location of holes for the external damper coupling on the chord of the profile are determined. Methods for optimizing the hanging of blades for raising the reliability of the last stages are suggested. Main results of hanging performed with the help of a specially developed “LIBRA” soft hardware are presented. __________ Translated from élektricheskie Stantsii, No. 11, November 2006, pp. 36–41.     

Calculating the thermally stressed state of the high and medium pressure rotors of a T-250/300-240 turbine in the labyrinth seal zone

The temperature and thermally stressed state of the high and medium pressure rotors of the T-250/300-240 district heating steam turbine are calculated, taking into account the concentration of stresses in the neighborhood of the thermal grooves in labyrinth seals. “Critical” zones in the turbine rotors, within which thermal stresses limit the rate of startup, are determined. Some practices for reducing the temperature stresses are suggested. __________ Translated from élektricheskie Stantsii, No. 1, pp. 32–37 (2008).     

Use of honeycomb seals in steam turbines

The appropriateness of using honeycomb seals in steam turbines is examined and the effective efficiency of using them is evaluated. It is shown that using honeycomb seals in the regulated stages and, in some cases, in the first unregulated stages, for the pressure in the high pressure cylinder, may be accompanied by losses of stability of the unit and the appearance of low frequency vibrations. Some examples of designs for seals in steam turbines with long lifetimes and enhanced antivibration properties proposed by leading foreign companies are discussed. Translated from élektricheskie Stantsii, No. 9, September 2008, pp. 40–44.     

Assessing the remaining life of bends of live steam conduits from steel 15Kh1M1F

It is shown that the remaining life of bends of steam conduits from steel 15Kh1M1F should be evaluated on the basis of results of estimation of microdamage of the metal performed on a representative sample with allowance for the operating factors. __________ Translated from élektricheskie Stantsii, No. 3, March 2006, pp. 29–32.     

Mathematical models for optimization of block diagrams and controller adjustment

The building of easily controlled production subassemblies is one of the urgent problems encountered in the development of heating systems for modern power plants. This paper describes a process by which a control system is built with subassemblies for the feed of basic condensate and steam to a deaerator by combined efforts of engineering and automation experts. __________ Translated from élektricheskie Stantsii, No. 8, August 2007, pp. 18–23.     

Problems of vulnerability of low-temperature rotors of cogeneration steam turbines to damage

Statistics of damage of steam turbine disks operating in the zone of phase transformation is analyzed and it is inferred that it is possible and expedient to determine group lives of rotor parts experiencing the action of permanent and objective negative factors. Statistics of damage in the form of circular cracks in low-temperature rotors of steam turbines of various types is presented. __________ Translated from élektricheskie Stantsii, No. 10, October 2006, pp. 36–41.     

Connecting the second exhaust-heat boiler to the operating first one under the conditions of flow circuits of combined-cycle plants with two gas-turbine units and one steam turbine

Problems arising with connecting the second exhaust-heat boiler to the first exhaust-heat boiler under load in the case of flow circuits of combined-cycle plants of type PGU-450 are considered. Similar problems exist for two-boiler single-turbine units of type PGU-325 and for two-boiler single-turbine units of traditional steampower plants with an output of 200–300 MW upon connection of the second furnace of a two-furnace boiler to the operating first furnace. Analysis of the temperature-induced stressed state and of the cyclic strength of thick-walled elements of the steam-water conduit of PGU-450 and of two-furnace boilers of two-boiler single-turbine units with an output of 200–300 MW (the check valve, the inlet header of the water economizer) is used for determining the steam temperature differences in the high-pressure conduits to the steam turbine and the order of connection of the second exhaust-heat boiler to the operating fist one. Modes of enabling a two-boiler single-turbine unit of a combined-cycle plant, which are most “rigid” from the standpoint of thermal strength, are determined. __________ Translated from élektricheskie Stantsii, No. 2, February 2006, pp. 11–17.     

Development,construction, and use of pneumometric tubes for measurement of steam flow in the steam lines of PVG-1000 at NPP

A system for the direct measurement of steam flow in steam lines after a steam generator, which utilizes a special design of pneumometric tubes and a computing unit that accounts for variation in steam pressure, has been developed to improve the quality of water-level regulation in the steam generators of VVéR-1000 power-generating units in the stationary and transitional modes. The advantage of the pneumometric tubes consists in their structural simplicity, high erosion resistance, and absence of irrevocable losses during measurement of steam flow. A similar measurement system is used at foreign NPP. The measurement system in question has been placed in experimental service at the No. 3 unit of the Balakovo NPP, and has demonstrated its worthiness. This measurement system can also be used to determine steam flow in the steam lines of NPP units with VVéR-1000 and VVéR-440 reactors, and PBMK-1000 power-generating units. __________ Translated from élektricheskie Stantsii, No. 3, March 2007, pp. 23–26.     

Geomechanical aspects of the effect of large reservoirs on rock masses

Conclusions  

An estimate of the errors when calculating the varying electric power losses in overhead lines due to neglecting weather conditions

An algorithm for calculating the resistance taking into account the air temperature, the working current and the wind speed is developed. A quantitative estimate is made of the effect of the load current, the conductor temperature and the wind speed on the resistance of overhead-line conductors. The ranges of the errors in calculating the annual variable electric power losses are obtained. 1 Electric Power Scientific-Research Institute (VNIIé)—subsidiary of JSC “NTTs élektroénergetiki,” Russia. Translated from élektricheskie Stantsii, No. 10, October 2008, pp. 42–49.