Vízügyi Közlemények, 1963 (45. évfolyam)

4. füzet - VIII. Könyvismertetés

"(37) BRIEF PUBLICATIONS 1. I. Somody, Mech. Eng.: Pumped Storage (For the Hungarian text see pp. 215) The equalization of daily fluctuations in consumption presents ever increasing difficulties in interconnected power supply systems. In the majority of countries thermal power stations comprise the bulk of installed capacity (Table I), the operation of which must be uniform to be economical. Various attempts have been made so far for the equalization of the daily load diagram, ranging from preferential rates to scheduled operation. Economical storage of energy can be realized with hydroelectric power stations only. Pumped storage depends, naturally, on hydrological and topographical conditions, but oppurtunities for pumped storage are being developed at a high rate all over the World (Table II). In the German Federal Republic there are plans to increase the capacity installed at pumped storage plants from the I960 level of 740 MW, to 3300 MW by 1975. The overall efficiency of pumped storage revealed a steeply improving trend and is now about 70 per cent in contrast to the initial 40 per cent. Pump efficiencies have also improved considerable. E. g. at the Geesthacht plant an efficiency of 90.8 per cent was recorded instead of the guaranteed 89.6 per cent (Fig. 5). A peak overall efficiency has been guaranteed for the Vianden development (Fig. 6). The economical aspects of pumped storage are significantly improved thereby, especially in comparison with thermal power stations operating less than 2400 hours annually. This fact has been corroborated also by the economical analyses carried out in Great Britain. Pumped storage is, naturally, greatly affected by local conditions. Data of Böhler (4) on investment expenditures are reproduced in Fig. 7. Some of the numerous additional favourable features of pumped storage plantsare : the ability to attain peak power output in a very short time, to take care — thanks to its rapid reversibility — of extreme load fluctuations, and its suitability for acting as a phase alternator. Further opportunities are offered by the introduction of the new Deriaz pump-turbine units, the technical features of which are shown in Figs. 8 and 9. 2. Szilvássy Z. Eng. : Radioaetive soil density measurement. (For the Hungarian text see pp. 223) Besides the utilization of radioactive isotopes as tracers, the measurement, of radiation absorption offers the possibility for the field determination of soils and earth structures. The indirect methods developed so far rely in general on sampling, and are thus unable to yield representative results in spite of the lengthy procedure involved. Such investigations consist of two steps: the determination of the moist bulk density and the moisture content. From these data the degree of compaction can be calculated. The determination of the moist bulk density is made possible by the Compton effect. The mutual effect between the gamma-radiation of radioactive isotopes and the soil can be utilized by two basic types of arrangement, the first of which relies on the measurement of backscattered radiation (Fig. 1.), while the second on the damping of gamma-radiation by absorption (Fig. 3). Both arrangements are suitable for density measurements at the surface, or at greater depths. The moisture content can be measured by counting the slow neutrons, produced by the damping of fast ones through collision with hydrogen atoms present in the soil. The validity limits, accuracy and the instrument constants can be determined from the literature for various arrangements. A suitable method and instrument has been developed in Hungary by the Railway Research Institute.