Estimation of the Technical Condition of Overhead Transmission Lines After 30 Years of Operation

Results of an inspection of 220-kV overhead transmission lines (OTL) in the Cherepovets network of the Vologdaénergo Company performed with the use of specially developed Methodological recommendations for estimation of the technical condition of 35 – 750-kV OTL after long-term operation are discussed. The reliability margin of poles and footings is determined by calculation of actual loads on unified structures. Conductor sizes are evaluated in all spans and the distribution of out-of-size places over the OTL route is determined without resorting to expensive geodetic surveys. Two ways for solving the problem of further safe operation of the studied OTL are suggested, namely, traditional (restoration of appropriate clearances to earth by heaving the conductor or erecting new poles) and alternative (determination of the latent margin contained in the Rules for design of electric installations, allowance for the actual current load on the line and the true size of farm equipment used over the route, etc.) ones. It is recommended to find individual solutions to problems arising in OTL after long-term service.     

Percolation and Dispersion of Mass Transport in Saturated Fracture Networks

Dispersion and transport of mass in a fracture network is a percolation process. Macro-scale dispersion is related to travel time, distance, mass distribution and fracture geometry. This article presents a stochastic, discrete fracture model in conjunction with percolation theory to investigate the dispersion phenomenon and the power law relationship between mean square travel paths displacement r2 and particle travel time t. For imposed boundary conditions, particle dispersion is simulated to observe percolation thresholds and dispersion trends in different network structures. Simulation results demonstrate that the critical exponent values of t in the percolated networks are extremely close to the theoretical value of 1.27 and occur at certain percolation factors. Below these percolation factors, the exponents of t increase with decreasing percolation factors, above these percolation factors, exponents decrease with increasing percolation factors. In our simulated cases, the proportionality between r2 and time t is given by t raised to a power between 1.27 and 1.66, depending on the fracture pattern. The coefficient of anisotropic dispersion tensor increases with increasing distance. The percolation process is related to travel time and distance, and cannot be interpreted as a Fickian diffusive process.     

Evaluation of Performance Efficiency of Vibration Damper on a Conductor

The method suggested makes it possible to determine maximum amplitudes of standing vibration waves, slopes of the conductor with respect to horizontal, bending moments, and cutting forces in any cross section of the conductor and of the flexible element of the vibration damper with the help of SVT — Conductor with Vibration Damper software for any grade of conductor, earth wire, or vibration damper (GPG). Comparative evaluation of parameters at the places of exit of the conductor from the supporting clamp and from the clamp of the vibration damper is performed.     

Determining Hydraulic Characteristics of Production Wells using Genetic Algorithm

Proper well management requires the determination of characteristic hydraulic parameters of production wells such as well loss coefficient (C) and aquifer loss coefficient (B), which are conventionally determined by the graphical analysis ofstep-drawdowntest data. However, in the present study, the efficacy of a non-conventional optimization technique called Genetic Algorithm (GA), which ensures near-optimal or optimal solutions, is assessedin determining well parameters from step-drawdown test data. Computer programs were developed to optimize the well parametersby GA technique for two cases: (i) optimization of B and C only, and (ii) optimization of B, C and p (exponent) as well as to evaluate the well condition. The reliability and robustness of the developed computer programs were tested usingnine sets of published and unpublished step-drawdown data from varying hydrogeologic conditions. The well parameters obtained by the GA technique were compared with those obtained by the conventional graphical method in terms of root mean square error(RMSE) and visual inspection. It was revealed that the GA technique yielded more reliable well parameters with significantlylow values of RMSE for almost all the datasets, especially in caseof three-variable optimization. The optimal values of the parametersB, C and p for the nine datasets were found to range from 0.382 to 2.292 min m^-2, 0.091 to 3.262, and 1.8 to 3.6, respectively. Because of a wide variation of p, the GA techniqueresulted in considerably different but dependable and robust well parameters as well as well specific capacity and well efficiency compared to the graphical method. The condition of three wells was found to be good, one well bad and that of the remaining five wells satisfactory. The performance evaluation of the developed GA code indicated that a proper selection of generation number and population size is essential to ensure efficient optimization. Furthermore,a sensitivity analysis of the obtained optimal parameters demonstrated that the GA technique resulted in a unique set ofthe parameters for all the nine datasets. It is concluded thatthe GA technique is an effective and reliable numerical tool for determining the characteristic hydraulic parameters of production wells.     

Optimization of the water chemistry of the primary coolant at nuclear power plants with VVÉR

Results of the use of automatic hydrogen-content meter for controlling the parameter of hydrogen in the primary coolant circuit of the Kola nuclear power plant are presented. It is shown that the correlation between the hydrogen parameter in the coolant and the hydrazine parameter in the makeup water can be used for controlling the water chemistry of the primary coolant system, which should make it possible to optimize the water chemistry at different power levelsTranslated from Élektricheskie Stantsii, No. 12, December 2004, pp. 31 – 33.     

Experience in the Prevention of Frost Heave of Pile Foundations of Transmission Towers under Northern Conditions

Experience in the protection of pole foundations of transmission line objects from frost heave on the north of the Tyumen Region with the help of local cryosystems is described. A method for controlling the main factor determining the stability and reliability of operation of pole foundations of structures under unfavorable natural and climatic conditions is considered. Steady optimum temperature conditions of foundation soils are maintained for the entire period of existence of the object. A system for on-line control of the temperature conditions of soils of pile foundations of transmission towers and substation equipment and for their protection from frost heave with the help of seasonally functioning cooling devices (SCD) and thermal stabilizers (TS) is developed. Recommendations are given on effective use of the developed method. Data on commissioning of local cryosystems at objects served by Northern Electric Networks of the Tyumen'énergo Company are presented. The works were performed in cooperation with the department of cryology of Moscow State University and VNIIgaz.     

再生粗骨料和矿物掺合料对再生混凝土抗冻性影响的研究

试验研究了不同再生粗骨料取代率对再生混凝土抗冻性的影响,并且以再生粗骨料取代率为100%的再生混凝土作为基准混凝土,分别研究单掺钢渣粉、硅灰以及复掺钢渣粉、硅灰对再生混凝土抗冻性的影响。试验分别从表观特征、质量损失率、相对动弹性模量和抗压强度来分析。试验结果表明:随着钢渣掺量的增多再生混凝土的抗冻性降低;硅灰明显的提高再生混凝土的抗冻性,掺量5%为宜;复掺钢渣和硅灰不同的比例对再生混凝土的抗冻性影响不同,得到复掺硅灰5%+钢渣15%再生混凝土的抗冻性优于基准混凝土。     

Efficient steam turbines produced by the “Ural Turbine Plant” company

Design features and efficiency of some steam turbines produced at present by a plant formed as a result of division of the Turbine Motor Plant Company into several enterprises are presented.Translated from Élektricheskie Stantsii, No. 11, November 2004, pp. 27 – 32.     

Experience with and the effectiveness of automatic systems for control of loading-hauling operations during construction of the dam for Nurek hydroelectric plant

Conclusions Experience with use of the Karat automatic control system during construction of the dam for the Nurek hydroelectric plant demonstrated its high cost effectiveness and the expediency of using similar systems in similar projects, and, in particular, in the construction of the dam for the Rogun hydroelectric plant.Translated from Gidrotekhnicheskoe Stroitel'stvo, No. 11, pp. 6–9, November, 1980.     

Information Structure and Software for Processing and Storing Data on Operating Environment and Parameters

A structure and software for processing data on operating environment and parameters of power objects and pools are presented. A information model employing object and temporal approaches is suggested. The model permits classification of equipment and objects and storage of operating states of equipment with binding the measured parameters to them. The model is used as a base for developing Energostat software for processing data at some power enterprises in Russia.     

Development and application of a real-time flood forecasting system in the Veneto region of Italy

The paper describes three flood forecasting models used in the framework of the integrated hydrological forecasting system of the Veneto Region. The three models are based on the unit hydrograph theory, even though the computation of the effective rainfall and the real-time correction procedure are carried out in different ways. A comparison of the model performances is also made.     

Spectral Reflectance,Growth and Chlorophyll Relationships for Rice Crop in a Semi-Arid Region of India

Relations among spectral reflectance, chlorophyll a, and growth of rice plants grown on irrigated light textured soil in a semi arid region are presented here. There was a linear relation between spectral reflectance and rice plant height (r = 0.97), for band 1 (0.45–0.52 m) reflectance values. On the other hand, in bands 2 (0.52–0.60 m) and 3 (0.63–0.69 m), reflectance values decreased until 70 days after planting (DAP) and then increased during the reproductive phase of the crop. The near infrared band 4 (0.76–0.90 m) showed a maximum reflectance at 59 DAP (panicle initiation stage) and a decline in reflectance thereafter through maturity. The peak value of IR/R ratio was 16.39 at 62 DAP during the early reproductive phase; thereafter, it declines gradually with the maturity of the crop. Chlorophyll a concentration was high during early growth (vegetative and early reproductive stages) and decreased during the flowering and maturity stages. The rice plant canopy show a high chlorophyll a concentration at 64 and 59 DAP for sites A and B, respectively. Chlorophyll a concentration is higher in site A plant canopies than it is in site B during the entire crop cycle. A good inverse correlation (r = 0.91) has been found between chlorophyll a and band 1, while the IR/R ratio and the normalised difference vegetation index (NDVI) showed a relationship (r = 0.78) with the chlorophyll a concentration during the crop cycle. Band 2, 3 and 4 radiance values show a biphasic linear relationship with chlorophyll a concentrations, negative for early growth and positive for flowering and maturity stages. Results indicate that the period between 66 to 70 DAP is most suitable for the assessment of rice crop yield, based on chlorophyll a concentration.     

Hydrodynamic investigation of undershot discharge of radial gate

Conclusions The hydrodynamic theory for the undershot discharge of a straight radial gate in a conduit, in conjunction with modern computation methods and facilities, makes it possible to find the coefficients of contraction, pressure distribution, and total hydrodynamic force acting on the gate.The results of the present investigation will lead to agreement between the experimental data where there is a maximum possible fulfillment of the requirements presented at the start of this article in regard to the flow (flow should be close to two-dimensional, the Froude number Fr = v ² /gH sufficiently high, etc.).Translated from Gidrotekhnicheskoe Stroitel'stvo, No. 1, pp. 36–39, January, 1981.     

Hydrogeothermal theory of earthquakes — Basis of prediction,warning systems,and counteractions

Conclusions The developed theory of the hydrogeothermal origin of earthquakes should be considered sufficiently well-founded and having universal application both to technogenic and to ordinary earthquakes. It has great prospects for developing automatic earthquake warning and counteraction systems.Translated from Gidrotekhnicheskoe Stroitel'stvo, No. 2, pp. 58–61, February, 1990.     

粉煤灰掺量对泵送混凝土碳化及抗冻性的影响

为了研究不同水胶比、不同粉煤灰掺量对泵送混凝土的碳化及抗冻性能的影响,进行了相关试验。试验结果表明:泵送混凝土的碳化深度随粉煤灰掺量、水胶比、龄期的增长而增长;相比常态混凝土,粉煤灰对泵送混凝土抗碳化性能较为有利;掺SP-8N泵送混凝土的抗碳化及抗冻性能略高于掺JM-2混凝土;粉煤灰掺量为30%,水胶比从0.30变化至0.50时,泵送混凝土均具有较好的抗冻性能;水胶比是影响泵送混凝土碳化及抗冻性能的主要因素。     

水工混凝土耐久性研究的新进展

国家“九五”攻关“混凝土抗冻性研究”和“耐化学腐蚀及高耐蚀材料的研究”两个专题中,包括了高抗冻超抗冻混凝土的开发及应用、高强混凝土的抗冻性、混凝土抗冻性的定量化设计、荷载和高浓度硫酸盐侵蚀的研究,以及压力水下混凝土渗漏溶蚀的研究等子题。研究成果已通过国家科技部的鉴定,并在三峡大坝等工程中得到了应用,取得了良好的效果。     

Operational performance of canal control systems

Three canal control systems (manual upstream control, automatic upstream control and automatic downstream control) were studied for the main canal of the Shoeibieh irrigation project in Iran. The canal and the selected control systems were modelled in a hydrodynamic modelling package. The operational performances of the canal control systems were investigated and quantified for two water delivery schedules, one with small, but frequent adjustments and the other one with big, but infrequent adjustments. Based on the results of the study, automatic upstream control with a small step delivery schedule has been selected for the project.Paper presented at the European Conference Advances in Water Resources Technology, Athens, 20–23 March 1991.     

Automated model of an engineering-natural object

Conclusions When developing a Natural conditions CAD it is expedient to take a model of the engineering-natural object as its basis. It is a general-purpose automated information system consisting of differently organized and combined modules.The universality of the model enables its use not only during designing but also for solving practical problems during construction works.Management of earthworks during construction of the dam of the upper reservoir and taking slide-control measures at the Zagorsk PSS are examples of such use.Translated from Gidrotekhnicheskoe Stroitel'stvo, No. 3, pp. 40–42, March, 1993.     

Pre-posterior analysis as a tool for data evaluation: Application to aquifer contamination

This paper deals with the frequently encountered problem of pre-posterior data evaluation, i.e., assessment of the value of data before they become available. The role of data is to reduced the risk associated with decisions taken under conditions of uncertainty. However, while the inclusion of relevant data reduces risk, data acquisition involves cost, and there is thus an optimal level beyond which any addition of data has a negative net benefit. The Bayesian approach is applied to construct a method for updating decisions and evaluating the anticipated reduction in risk following consideration of additional data. The methodology is demonstrated on a problem of management of an aquifer under threat of contamination.Notation L matrix of losses for all combinations of states and decisions - l, m, h possible salinity levels from the proposed borehole - N, M, F possible decisions - P(·) vector of prior probabilities of states - P(.|l), P(.|m), P(.|h) conditional (updated) probability vectors of the different states given the salinity levels - P(.|), P(.|), P(.|) probability vectors of the different salinity levels given the true states (likelihood function) - P(l), P(m), P(h) probabilities of the salinity levels, irrespective of the true state - R(.|l), R(.|m), R(.|h) posterior risk vectors of the different decisions given the salinity levels - R(N), R(M), R(F) prior risk associated with different decisions - , , possible true states     

Analytical method of calculating slope stability

Conclusion Methods of calculating slope stability in which the equilibrium conditions are not fulfilled can be used only for preliminary calculations if there are no considerable horizontal loads. In this case, it is recommended to use Terzaghi's method, introducing our proposed correction factor to the frictional forces on the failure surface.In critical calculations it is necessary to use methods in which the equilibrium conditions are fulfilled. They give practically the same results.The proposed analytical method makes it possible to calculate stability without dividing the failure mass into vertical elements (columns). It seems to us the most simple and accessible of the rigorous methods.Translated from Gidrotekhnicheskoe Stroitel'stvo, No. 12, pp. 9–14, December, 1989.