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.     

Use of a magnetization effect for monitoring thermal inhomogeneities in steam superheaters made of 12Kh18N12T steel

Coils of 12Kh18N12T steel become magnetized during operation because the surface layer of the metal at the scale boundary is depleted in chromium and enriched in ferromagnetic nickel. A large-scale study of the relationship between the thickness of the altered layer and the operating temperature and individual service life is underway at Mosénergo’s TéTs-26 heating and electric power plant. Ferritometry and selective replacement have made it possible to reduce the amount of strain-induced and embrittlement damage and to extend the service life of steam superheaters. This could not be done by traditional methods, in particular ultrasonic monitoring of the wall thickness. The data obtained here can serve as a basis for creating a new technique for monitoring thermal inhomogeneity in steam superheaters made of austenitic steels. The advantages of ferritometric monitoring include the following: special preparation (cleaning) of coils is not required, the measurements are convenient, and segments with the highest temperature can be detected. __________ Translated from élektricheskie stantsii, No. 12, December 2007, pp. 22–25.     

The switching life of short-circuit contact breakers in power systems

Integral distributions of the actual values of short-circuit currents in the 100–500 kV networks, obtained by processing oscillograms of the transients in electrical transmission lines, are presented. It is shown that in the majority of newly established modern gas-filled contact breakers with spring-loaded drive mechanisms the switching and mechanical lives will not be exhausted after their useful life. Hence, planned repairs of such contact breakers can be predicted starting from their actual state and not from the fixed inter-repair periods. * JSC “Otdelenie Dal'nikh Peredach,” Russia. ** Electric Main Line Network Center (MéS Tsentra), Russia. *** IVTs Mosénergo, Moscow, Russia. **** Moscow Power Institute – Technical University, Moscow, Russia. ***** JSC “énergoservisproekt,” Russia. Translated from élektricheskie Stantsii, No. 10, October 2008, pp. 59–62.     

Use of heat-resistant chromium-aluminum steel for tube spacers in superheaters of boiler units

Results of investigations and industrial testing of heat-resistant chromium-aluminum steel 03Kh18Yu3BT are presented; from these results, this steel can be recommended for the fabrication of spacers, mounting hardware for the heating surfaces of the superheaters of boiler units, and other lightly loaded articles operating at high temperatures during the burning of all types of fuels used in the firing of thermoelectric power plants. __________ Translated from élektricheskie Stantsii, No. 9, September 2007, pp. 34–37.     

Assessing groundwater quality using GIS

Assessing the quality of groundwater is important to ensure sustainable safe use of these resources. However, describing the overall water quality condition is difficult due to the spatial variability of multiple contaminants and the wide range of indicators (chemical, physical and biological) that could be measured. This contribution proposes a GIS-based groundwater quality index (GQI) which synthesizes different available water quality data (e.g., Cl⁻, Na⁺, Ca²⁺) by indexing them numerically relative to the World Health Organization (WHO) standards. Also, introduces an objective procedure to select the optimum parameters to compute the GQI, incorporates the aspect of temporal variation to address the degree of water use sustainability and tests the sensitivity of the proposed model. The GQI indicated that the groundwater quality in the Nasuno basin, Tochigi Prefecture, Japan, is generally high (GQI <90). It has also displayed the natural (depth to groundwater table, geomorphologic structures) and/or anthropogenic (land-use and population density) controls over the spatial variability of groundwater quality in the basin. Temporally, groundwater quality is more variable in the upper and lower parts of the basin (variation, V, 15–30%) compared to the middle part (V, <15%) probably attributed to the seasonality of precipitation and irrigation of rice. In the lower southeastern part of the Nasuno basin and the vicinity of the Naka and Houki rivers the sustainable use of groundwater is constrained by the relatively low and variable groundwater quality. The model sensitivity analysis indicated that parameters which reflect relatively lower water quality (high mean rank value) and those of significant spatial variability imply larger impacts on the GQI and must be carefully and accurately mapped. Optimum index factor technique allows the selection of the best combination of parameters dictating the variability of groundwater quality and enables an objective and fair representation of the overall groundwater quality.     

Efficiency of operation of a T-250/300–240 turbine without moving blades of last stages of the low-pressure cylinder

The results of detailed computations performed for actual electric and heat loads, pressure in the condenser, and other operating parameters are used to consider the changes in the efficiency of operation of a T-250/300–240 turbine after the removal of moving blades of the last stages of the low-pressure cylinder. It is shown that the expediency of running the turbine with removed blades should be determined proceeding from the expected modes of operation of the cogeneration plant in question for the whole year. __________ Translated from élektricheskie Stantsii, No. 11, November 2005, pp. 47–52.     

Increasing the corrosion resistance of equipment due to the use of film-forming amines

Results of a study of tube specimens cut from hot-water boilers show that film-forming octadecyl amine (ODA) used in the process of preservation removes deposition from the surface of the metal. An ODA film is preserved on the surface after repeated washing of the latter with hot water. The concentration of chlorides at the surface of the metal after treatment with ODA is lower than before the treatment. __________ Translated from élektricheskie Stantsii, No. 11, November 2005, pp. 15–18.     

Main principles for construction of relay protection of 330–750-kV equipment with the use of microprocessor devices of series Shé2710

The basic principles for construction of relay protection of the equipment of 330–750-kV networks and substations with the use of microprocessor devices of series Shé2710 produced by the “éKRA” Research and Production Enterprise (Cheboksary) are considered. __________ Translated from élektricheskie Stantsii, No. 9, September 2005, pp. 42–45.     

A study of the high-temperature strength and crack resistance of the metal of the body of stop valve from high-chromium steel 15Kh11MFBL after long-term operation

The applicability of the rapid method for determining the ultimate long-term strength, endurance, and crack resistance of cylindrical specimens with three sharp notches, which has been developed by V. I. Gladshtein for pearlitic steels, to chromium steel 15Kh11MFBL is considered. It is shown that the results of evaluation of high-temperature strength by the standard method and with the use of notched specimens supplement each other. Prediction of the time before failure of smooth specimens from notched specimens makes it possible to perform the evaluation for 100,000–300,000 h, which is impossible by direct testing at operating temperatures. __________ Translated from élektricheskie Stantsii, No. 10, October 2005, pp. 78–80.     

Use of various methods for suppressing internal corrosion of the thermal network at the Novomoskovsk state regional electric power plant

The results of using several water-chemical regimes for the thermal network (pH = 8.3–9.0; pH greater than 10; pH = 8.6–8.9 in the presence of a corrosion inhibitor) are reported. The rates of internal corrosion under these regimes are estimated. The regime with pH = 8.6–8.9 and a corrosion inhibitor and the regime with pH greater than 10 are found to produce the same effect. Translated from élektricheskie Stantsii, No. 10, October 2008, pp. 36–38.     

Operating experience with and problems of lightning protection for the first domestic 220-kV overhead lines from the lower Svir’ HPP to the Lenénergo

Results of analysis of operating experience with automatic disconnection of the first domestic 220-kV overhead lines from the Lower Svir’ HPP to a substation in the settlement of Kolpino in the Leningradskaya Oblast’ (two Svir’ 220-kV overheads lines with a length of 247 km) over a period of 21 years (1982–2002) in total volume of 10,400 km · year are presented. Operating indicators are established with respect to specific number of disconnects and stream of failures per 100 km of overhead lines. Indicators of lightning-surge protection on the 220-kV Svir’ overhead lines passing through the same corridor primarily along a swath cut through a forest in periods when the stranded cables were protected by different schemes — stranded cable only on approaches to substations, incomplete and nonuniform protection along the route — are compared. Recommendations are given for optimal cable protection of the 220-kV Svir’ overhead lines. __________ Translated from élektricheskie Stantsii, No. 4, April 2007, pp. 49–59     

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.     

Hydrologic and Hydrogeologic Characterization of a Deltaic Aquifer System in Orissa, Eastern India

The present study focuses on the in-depth hydrologic and hydrogeologic analyses of Kathajodi-Surua Inter-basin within the Mahanadi deltaic system of Orissa, eastern India to explore the possibility of enhanced and sustainable groundwater supply. The results of 6 years (2001–2006) streamflow analysis indicated that the river flow is highly seasonal and it reduces to almost no flow during summer seasons. Land use map of the study area for the monsoon (Kharif) and post-monsoon (Rabi) seasons was developed by remote sensing technique and runoff estimation was done by curve number method. The runoff estimated for the 20-year period (1990–2009) varied from a minimum of 10.2% of the total monsoon rainfall in 1995 to a maximum of 43.3% in 2003. The stratigraphy analysis indicated that a leaky confined aquifer comprising medium to coarse sand exists at depths of 15 to 50 m and has a thickness of 20 to 55 m. The analysis of pumping test data at 9 sites by Aquifer-Test software indicated that the aquifer hydraulic conductivity ranges from 11.3 to 96.8 m/day, suggesting significant aquifer heterogeneity. Overall groundwater flow is from north-west to south-east direction. There is a 5 to 6 m temporal variation and 3 to 4 m spatial variation of groundwater levels over the basin. The rainfall-groundwater dynamics and stream-aquifer interaction in the river basin were studied by correlation analysis of groundwater level with weekly rainfall and river stage. The correlation between the weekly rainfall and weekly groundwater level was found to vary from ‘poor’ to ‘fair’ (r = 0.333 to 0.659). In contrast, the weekly groundwater level was found to be strongly correlated with the weekly river stage (r = 0.686 to 0.891). The groundwater quality was found suitable for both irrigation and drinking purposes. It is recommended that a simulation-cum-optimization modeling following an integrated approach is essential for efficient utilization of groundwater resources in the study area.     

Nomograms for preliminary design of pressure tunnel linings

Conclusions By means of the proposed nomograms it is possible to select at preliminary stages of design the economically advantageous types and dimensions of linings of tunnels being driven in isotropic rocks. From an examination of the solutions obtained from the nomograms, we can draw the following conclusions, which have also been included in the “Instructions on the Designing of Hydraulic Tunnels,” namely: a) it is recommended to use concrete linings in tunnels with an inside diameter up to 6 m in rocks withf _st=2–10 at internal water pressure heads not exceeding 20–90 m, respectively; here it is recommended to take into account the economy of labor expenditures in comparison with other types of linings; b) reinforced-concrete linings should be used: in weak rocks (f _st=0.5–1.0) at internal water heads to 40 m and in stronger rocks (f _st≥2) for tunnels with D_i=5 and greater at heads to 50 m, and in strong rocks (f _st=15) to 140 m; c) two-layer linings with an inner reinforced-gunite ring up to 15 cm thick should be used at heads of 50 m and greater in rock of medium strength and higher (f _st≥3); d) two-layer linings with an inner steel shell should be used in granular and soft rocks (f _st=0.5–1.0) with D_i≥10 m, and also at neads of 40 m and greater for any tunnel sections in these rocks and in cases of the economic inexpediency or structural impossibility of using other types of linings. Translated from Gidrotekhnicheskoe Stroitel’stvo, No. 4, pp. 15–19, April, 1973.     

Behavior of phosphates in a high pressure drum boiler with frequent loading

The overall contamination of the baffle pipes in a high pressure drum boiler in the phosphate water-chemical regime is estimated based on the increase in the concentration of phosphates in the boiler water during unloading of the boiler to approximately 50% of nominal. Translated from élektricheskie stantsii, No. 6, June 2008, pp. 29–33.     

A Water Model for Water and Environmental Management at Mae Moh Mine Area in Thailand

It is revealed that the water quality in Mae Moh Reservoir, Thailand, has been deteriorated by lignite mine drainage and power station effluent. This study aims to manipulate water quantity and quality to reduce environmental impacts in Mae Moh area through a model for water management. The model was constructed on the basis of materials balance to predict water flow, which includes concentrations of TDS and SO ^2– ₄. Data collected during 1996–2000 were used. Model validation showed that the mean of predicted and actual values of TDS and SO ^2– ₄ load were significantly similar at 95% confidence limit. The test result is acceptable and the water model can be used as a tool for water system management in the area. In 2006, Mae Moh mine excess water will be discharged at 10.76 Mm³, with a pH of 7.3, TDS and SO ^2– ₄ concentrations of 2,547 and 1,803 mg/l, respectively. Mae Moh power station effluent will be 14.59 Mm³, with pH of 7.1, TDS and SO ^2– ₄ concentrations of 610 and 358 mg/l, respectively. Predicted results showed that the outflow of Mae Moh Reservoir will be 83.67 Mm³ and the concentrations of TDS and SO ^2– ₄ will be as high as 1,501 and 822 mg/l, respectively. Mine excess water management measures are recommended according to the following strategy. All mine excess water should be stored during dry season. During wet season, 50% of the excess water should be stored and the remaining treated at 90% of TDS removal before being discharged. The end result would be a significant improvement in water quality in the Mae Moh Reservoir over the 4-year period to 2010. Pollutants in terms of TDS would be reduced by 35% from 1,501 mg/l in the beginning of 2006 to 975 mg/l at the end of 2009.     

Improvement of the process of fuel firing on BKZ-210-140F boilers

The existing flame processes of dual firing of gas and solid fuel are updated with reconstruction of the burners at the Chelyabinsk TéTs-2. This is connected with marked worsening of the quality of local coal supplied to the cogeneration plant. Comparative tests of boilers with burners subjected to different degrees of updating have shown that replacement of the now used swirled method of introduction of reagents into the furnace by a uniflow one lowers the heat flows to the metal structures and to the settling of the burner throats making them more reliable. The emission of nitrogen oxides is minimized in the mode of gas firing and the activity of slagging of the furnace and of the platens is reduced in the mode of coal firing, which makes it possible to raise the steam rate of the boiler. Ways for further improvement of burner design with respect to nitrogen oxide emissions in the polydisperse flame are outlined. __________ Translated from élektricheskie Stantsii, No. 11, November 2006, pp. 13–19.     

Operating and repair experience gained with closed hydraulic conduits of the No. 5 heating and power plant operated by the leningrad district administration of power facilities

Conclusions The method used at the No. 5 heating and power plant of the Leningrad District Administration of Power Facilities for repairing underground hydraulic conduits by guniting over a metal reinforcing grid merits application in other establishments with the guarantee of a 15–20 yr service life. Translated from Gidrotekhnicheskoe Stroitel'stvo, No. 4, pp. 43–44, April, 1977.     

Operational Reliability and Service Life of Station Steam Conduits of Active 800-MW Power-Generating Units

Problems of the safe and long-term operation of live steam and hot reheat conduits of 800-MW power-generating units are discussed. The condition of the metal of steam conduits of 800-MW units is analyzed using the data of nondestructive testing, studies of the properties of cutout specimens, and computations of the remaining life after various operating periods. It is shown that long-term service of metal in steam conduits, which have been produced by different methods from large-diameter pipes of steel 15Kh1M1F, at domestic and foreign plants softens the metal considerably. In some cases, impermissible defects in the form of cracks and other damage accelerate the failure. Computations made with allowance for the actual condition of the structure and properties of pipes show that the service life of live steam conduits from standard 465 × 75 mm pipes and hot reheat conduits from 920 × 32 mm pipes fabricated from steel 15Kh1M1F should be limited to 150.0 and 130.0 thousand hours, respectively, at design steam parameters.     

Adaptation to Climate Change in the Management of a Canadian Water-Resources System Exploited for Hydropower

The management adaptation potential of the Peribonka River water resource system (Quebec, Canada) is investigated in the context of the evolution of climate change. The objective of this study is to evaluate the impacts on hydropower, power plant efficiency, unproductive spills and reservoir reliability due to changes in the hydrological regimes. The climate change projections used here are from the Canadian regional climate model (CRCM) nested by the Canadian-coupled global climate model (CGCM3) forced with the SRES A2 greenhouse gas emission scenario. The hydrological regimes were simulated with the distributed hydrological model Hydrotel. They were incorporated into a dynamic and stochastic optimization model in order to adapt the operating rules of the water resource system annually, according to the evolution of the climate. The impacts were analyzed over the years 1961–2099, split into four periods for comparison purposes: control period (1961–1990), horizon 2020 (2010–2039), horizon 2050 (2040–2069) and horizon 2080 (2070–2099). The main results indicate that annual mean hydropower would decrease by 1.8% for the period 2010–2039 and then increase by 9.3% and 18.3% during the periods 2040–2069 and 2070–2099, respectively. The trend to increase is statistically significant starting from 2061 (Mann–Kendall with p = 5%). The change in the mean annual production is statistically significant for the 2040–2069 and 2070–2099 periods (t-test with p = 5%). Also, the change in the variance is significant for the periods 2010–2039, 2040–2069 and 2070–2099 (F-test). Annual mean unproductive spills would increase from 1961–2099, but the trend is not statistically significant. However, the changes in the variance of the annual mean spills are significant in the periods 2010–2039, 2040–2069 and 2070–2099. Overall, the reliability of a reservoir would decrease and the vulnerability increase as the climate changes.