Design of twin-circuit towers for 500-kV OTL on inhabited localities

The experience of the “Otdelenie dal’nikh peredach” (ODP) Company on the design of multi-circuit overhead transmission lines (OTL), including towers for 500-kV lines, is described. It is suggested that specifications should be developed to supplement the “Rules for Construction of Electric Installations” as a first step for conversion of twin-circuit 500-kV OTL. __________ Translated from élektricheskie Stantsii, No. 11, November 2006, pp. 65–67.     

Power losses in electrical networks depending on weather conditions

Specific power losses to corona and to leakage currents over overhead insulators are presented for 110 – 750-kV transmission lines with different phase design and pole types for different weather conditions. Consumption of electric energy for ice melting on conductors of various cross sections is evaluated. Meteorological data of 1372 weather stations in Russia are processed for a period of 10 years. The territory of the country is divided into 7 regions with approximately homogeneous weather conditions. Specific power losses to corona and leakage currents over overhead insulators are presented for every region.Translated from Élektricheskie Stantsii, No. 11, November 2004, pp. 42 – 48.     

General characteristic of electric field intensity of 500-kV outdoor switchgears

Evaluation of the risk of damage to the health of personnel servicing 500-kV electrical installations due to the action of commercial-frequency electric field is described. Using the results of a study performed at several objects of the Trunk Electrical Networks (TEW) of Ural Region, the authors suggest measures for lowering the effect of the field on the personnel. __________ Translated from élektricheskie Stantsii, No. 1, January 2006, pp. 45–48.     

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     

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.     

Reliability of 330- and 500-kV Transmission Lines of the United Power System of Northern Caucasia

The necessity for employing nonparametric methods for evaluating statistical data on failures of transmission lines is substantiated. A method for evaluating the reliability of transmission lines based of the life characteristic of the object is suggested. The reliability of 330- and 500-kV transmission lines of Northern Caucasia is evaluated with the help of the methods suggested. __________ Translated from Elektricheskie Stantsii, No. 7, July 2005, pp. 58 – 64.     

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.     

A method of increasing the operating reliability of high-frequency protection

The breakdown of the PDE 2003 type directed and differential-phase high-frequency protection based on integrated microcircuits for a single-phase short circuit on a 330-kV line when the protection is operating in the directed mode is considered. It is shown that separation of the exposure time in the disconnection channel into two parts increases the operating reliability of the protection for disconnection in intensive high-frequency interference. The establishment of maximum (apparatus) sensitivity of the high-frequency receiver is only possible in icy regions. Translated from élektricheskie Stantsii, No. 12, December 2008, pp. 58–61.     

Experience with Siberian Centralized Dispatch Regulation regarding location determination of damages sustained by intersystem high-voltage transmission lines

A set of measures that can be implemented by the Relay-Protection and Automated-Equipment Service for Centralized Dispatch Regulation (CDR) in Siberia to determine the location of damage sustained by inter-system 550-and 220-kV transmission lines maintained by the United Power System (UPS) of Siberia, and the methodology and technology of damage-location determination (DLD) are described. The damage sustained by the 500-kV high-voltage lines (HL), and the accuracy of DLD relative to zero-sequence emergency parameters are analyzed statically. __________ Translated from élektricheskie Stantsii, No. 5, pp. 59–62, May, 2006.     

Installation of molten-metal seals in steam-turbine valves

Gaps in valves between the stems and boxes are a source of rather large steam and heat losses in power-generating steam turbines. A unique development of specialists employed by the Vserossiiskii Teplotekhnicheskii Institut — superairtight seals (SAS) with composite materials, which permit reliable sealing of valves with minimal friction within the system—is presented. Investigations conducted have indicated that the proposed type of SAS is capable of sealing gaps in valves with steam parameters of 29.75 MPa (300 kgf/cm²) and 600°C. __________ Translated from élektricheskie Stantsii, No. 1, January, 2007, pp. 35–37.     

Computational and experimental test of self starting regimes for the in-house needs of the PGU-450 steam-gas unit at the Kaliningrad TÉTs-2 Heating and Power Plant during supply disruptions

The major stages of a computational test of the self starting regimes for the in-house needs of unit No. 1 of the 450 MW steam-gas unit at the Kaliningrad TéTs-2 Heating and Electric Power Plant during supply disruptions are described. The results of an experimental test of five regimes are described and compared with the computational data. The results are analyzed. Recommendations are made for changes in the automatic reserve switching algorithms for the 6-kV sections, which, when realized, will ensure easier self startup for the mechanisms providing for in-house needs during supply disruptions. __________ Translated from élektricheskie Stantsii, No. 4, April 2008, pp. 46–55.     

A Study of Electromagnetic Radiation of Corona Discharge Near 500-Kv Electric Installations

Data on the spectral composition and intensity of electromagnetic radiation of corona discharge are obtained in an experimental study performed on the outdoor switchgear of the Shagol 500-kV substation of the Chelyabinsk Enterprise of Trunk Transmission Grids and under a 500-kV Shagol – Kozyrevo overhead transmission line. The electromagnetic environment on the territory of the 500-kV outdoor switchgear is shown to be determined by narrow-band radiations (harmonics of the frequency of electric supply) and wide-band radiations due to corona discharges of high-voltage sources. This means that the personnel experience the action of a commercial-frequency electric field and electromagnetic radiation of a quite wide range, which is not allowed for by the existing guidelines. It is recommended to continue the study in cooperation with medical institutions in order to create guidelines that would allow for the joint action of commercial-frequency electric field and electromagnetic radiation and for the voltage in the line, the current load, the meteorological situation, and other factors.     

Prediction of Hydropower Energy Using ANN for the Feasibility of Hydropower Plant Installation to an Existing Irrigation Dam

Recently, artificial neural networks (ANNs) have been used successfully for many engineering problems. This paper presents a practical way of predicting the hydropower energy potential using ANNs for the feasibility of adding a hydropower plant unit to an existing irrigation dam. Because the cost of energy has risen considerably in recent decades, addition of a suitable capacity hydropower plant (HPP) to the end of the pressure conduit of an existing irrigation dam may become economically feasible. First, a computer program to realistically calculate all local, frictional, and total head losses (THL) throughout any pressure conduit in detail is coded, whose end-product enables determination of the C coefficient of the highly significant model for total losses as: THL = C·Q ². Next, a computer program to determine the hydroelectric energies produced at monthly periods, the present worth (PW) of their monetary gains, and the annual average energy by a HPP is coded, which utilizes this simple but precise model for quantification of total energy losses from the inlet to the turbine. Inflows series, irrigation water requirements, evaporation rates, turbine running time ratios, and the C coefficient are the input data of this program. This model is applied to randomly chosen 10 irrigation dams in Turkey, and the selected input variables are gross head and reservoir capacity of the dams, recorded monthly inflows and irrigation releases for the prediction of hydropower energy. A single hidden-layered feed forward neural network using Levenberg–Marquardt algorithm is developed with a detailed analysis of model design of those factors affecting successful implementation of the model, which provides for a realistic prediction of the annual average hydroelectric energy from an irrigation dam in a quick-cut manner without the excessive operation studies needed conventionally. Estimation of the average annual energy with the help of this model should be useful for reconnaissance studies.     

Increasing the efficiency of the power stations of JSC “Mosénergo”

The work of the JSC“All-Russian Institute of Thermal Technology (JSC “VTI”) on electrical power stations of the “Mosénergo” power system is described. Two vital questions have arisen in the course of this work: ensuring the functionality and reliable operation of equipment which has outlived its design lifetime and refitting the power stations to enhance their performance, reduce their environmental impact, and improve their operational characteristics in accord with the demands of the 21^st century. __________ Translated from élektricheskie Stantsii, No. 11, November 2007, pp. 73–78.     

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.     

Efficiency of production of additional condensation power at dual-purpose turbine plants

Results of detailed computations (performed with the use of mathematical models of dual-purpose turbine plants) of the effect of the main operating factors on the energy and economic efficiency of the production of additional condensation power in the periods of power generation (at partially loaded heating extractions and flow of live steam below the rated value) are presented as applied to actual conditions of operation of turbines of different types. The results obtained show that the additional power can be quite competitive in the power market (at least in peak demand periods of the day) and that it is expedient to use dual-purpose turbines for managing electric demand. __________ Translated from élektricheskie Stantsii, No. 10, October 2006, pp. 26–32.     

Use of Static Compensators for Voltage Control at 330- and 500-kV Substations

A scheme for compensating the reactive power and controlling the voltage of high-voltage, intermediate-voltage, and low-voltage buses of 330 – 500-kV substations, which consist of static thyristor compensators (STC) on low-voltage autotransformers and controlled shunting reactors on high-voltage lines, is presented. It is shown that the STC can be created step-by-step beginning with the reactive part on substations with low-loaded lines. Results of installation of reactor groups of STC stepwise-controlled by vacuum switches at 330- and 500-kV substations are presented. Tests of the reactor groups have proved their high efficiency.     

Long-Range Backup of Protection and Breaker Failures in 0.4-kV Grids

The algorithm of a digital device for solving the problem of long-range backup of protection and breaker failures in 0.4-kV grids and simultaneous reduction of the setting for actuation of the protection of the transformers and generators feeding the grids is considered. Recommendations are given for choosing the actuation settings. The device has been tested under conditions close to field ones. The economic effect consists in prevention of fires due to fault-initiated protection failures and durable disabling of substations for repair works.     

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.     

The effect of the current of the melting ice cover in the lightning-protection cable on the relay protection of an electric power line

The reasons for the excessive operation of the zero-sequence current protection of an overhead electric power line when there is melting ice cover on the lightning protection cable in circuits using the ground as the return conductor are explained. Translated from élektricheskie Stantsii, No. 12, December 2008, pp. 55–57.