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     

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.     

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.     

Improvements in the computation of balances and localization of commercial losses of electric energy in 0.38-kV networks

An example of four 0.38-kV overhead distribution lines fed from a 10/0.4-kV transformer substation of the Grodno Electrical Networks (Belarus’) and supplying electricity to a cottage area is used for analyzing energy balances and commercial losses in the networks. It is shown that the reliability of such analysis can be ensured by the use of modern software and electronic energy meters recording a retrospective of half-hourly intervals of active and reactive electric energy. __________ Translated from élektricheskie Stantsii, No. 9, September 2006, pp. 51–61.     

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.     

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.     

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.     

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.     

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.     

Dedicated land disposal of wastewater sludge in south africa: leaching of trace elements and nutrients.

Most of the wastewater treatment facilities in South Africa (80%) dispose of their sewage sludge on dedicated land disposal (DLD) sites. The impact of this practice on the environment is believed to be negative, but very little research has been carried out to determine the extent of the damage to the soil and water resources. Forty wastewater treatment facilities using DLD, with different soil properties, application techniques, metal concentrations and period of sludge application, were studied. Soil and groundwater samples were collected at each of the selected facilities. Three extraction methods (aqua regia, NH4EDTA and NH4NO3) were used and samples were analysed for total N, P and K, pH, organic carbon and their metal content (Cr, Co, Ni, Cu, Zn, Cd, and Pb). Some degree of leaching of the heavy metals (especially Co and Ni) occurred at some of the sampling sites and the average depth of leaching was 100-200 mm. Deeper than 300 mm, the metal concentrations in most soil samples reached background concentrations. Seven of the nine groundwater samples that could be obtained had high NO3 concentrations (> 6 mg L(-1)). Statistical analyses of the data indicate no significant differences between sludge type (wet or dry) and leaching, or age of the disposal sites and leaching. Taking into account the age of the disposal sites, the frequency of sludge application and the metal load of the sludge, the depth of leaching is surprisingly shallow in most soils, in spite of the low soil pH(H2O) and clay content.     

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.     

Vitaliyi Cheslavovich Dorogostaisky: A Pioneer Investigator of the Flora and Fauna of Lake Baikal

V. Ch. Dorogostaisky was born in Irkutsk Province, and devoted much of his professional work to the study of Lake Baikal, Siberia, and its surrounding region. His studies spanned the first third of the 20th Century, beginning at the time when only isolated investigations of the lake were made. He organized and contributed to the shift toward systematic, sustained studies conducted by groups of specialists. His own contributions included both basic and applied efforts. Although he collected algae and vascular plants and described new species, Dorogostaisky devoted his principal attention in limnology to invertebrates and fish. He appears to have grasped the fundamentals of fish management and fur farming well ahead of the development of the technology. His most noteworthy contribution to basic science was his realization that the ecological speciation among the gammarids and fish of Baikal was a recent phenomenon. At a time when the very origin and antiquity of the lake itself was not known, he essentially documented adaptive radiation. Dorogostaisky's evidence impressed Cockrell (1927) to parallel Baikal's faunistic evolution with that of the Hawaiian Islands.     

混凝土徐变与损伤的耦合试验研究

本文重点研究了混凝土材料损伤对徐变变形的影响,以及混凝土非线性徐变过程中的损伤大小。本文将长期荷载下混凝土的性能作为研究对象,从混凝土徐变以及损伤两方面出发,运用超声波检测的方法测量混凝土内部损伤的演化规律,分析高持荷水平下混凝土材料发生徐变破坏的时间及对应的徐变变形,分析了徐变对混凝土材料损伤的影响规律,得出了高持续荷载下混凝土材料徐变与损伤相互影响的规律。     

Number of lightning discharges causing damage to lightning arrester cables for aerial transmission lines in power systems

Damage by lightning discharges to lightning arrester cables for 110–175 kV aerial transmission lines is analyzed using data from power systems on incidents with aerial transmission lines over a ten year operating period (1997–2006). It is found that failures of lightning arrester cables occur when a tensile force acts on a cable heated to the melting point by a lightning current. The lightning currents required to heat a cable to this extent are greater for larger cable cross sections. The probability that a lightning discharge will develop decreases as the amplitude of the lightning current increases, which greatly reduces the number of lightning discharges which damage TK-70 cables compared to TK-50 cables. In order to increase the reliability of lightning arrester cables for 110 kV aerial transmission lines, TK-70 cables should be used in place of TK-50 cables. The number of lightning discharges per year which damage lightning arrester cables is lowered when the density of aerial transmission lines is reduced within the territory of electrical power systems. An approximate relationship between these two parameters is obtained.     

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).     

Error of the Method of Determination of the Place of Damage of Overhead Lines Due to Ignored Phase Differences in Its Parameters

The effect of neglecting the influence of the phase asymmetry of parameters of overhead lines (OL) of different voltage classes on the accuracy of determination of the place of damage is discussed. The effect of phase transposition on the error of determination of the place of damage of a transmission line is evaluated by the methods of one-sided and two-sided measurement of the parameters of emergency operation. A method and software is suggested for substantial reduction of the error of the method of determination of the place of damage of overhead lines.     

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.     

Extending the time-to-overhaul of T-250/300-240 turbines built by the ural turbomotor plant and managed by Mosénergo

The paper discusses the condition of 19 turbines operated by the publicly owned joint-stock company Mosénergo, which have exhausted their time to overhaul (220,000 hours, 600 starts). An extension in the time-to-overhaul of all 19 turbines to 300,000 hours or 900 start ups with the condition that a number of mandatory measures be taken is an acknowledged possibility, based on calculations performed and analysis of damage sustained. A number measures, which have themselves been positively recommended for certain turbines, are examined, and a procedure is presented for evaluating the effectiveness of their implementation. __________ Translated from élektricheskie Stantsii, No. 6, pp. 4–8 (2006).     

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.