Physics of auroral phenomena : proceedings of the 40th annual seminar, Apatity, 13-17 March, 2017 / [ed. board: N. V. Semenova, A. G. Yahnin]. - Апатиты : Издательство Кольского научного центра РАН, 2017. - 143 с. : ил., табл.

“Physics o f Auroral Phenomena", Proc. XL Annual Seminar, Apatity, pp. 34-37, 2017 © Polar Geophysical Institute, 2017 Polar Geophysical Institute THE MAGNETIC FIELD VARIABILITY AND GEOMAGNETICALLY INDUCED CURRENTS IN ELECTRIC POWER LINES DURING MAGNETIC STORM MARCH 17, 2003 V.A. Pilipenko1, V.B. Belakhovsky2, Ya.A. Sakharov3, V.N. Selivanov4 1 Space Research Institute, Moscow 2Institute o f Physics o f the Earth, Moscow iPolar Geophysical Institute, Apatity 4Center o f Physical and Technical Problems o f the North Energetic, Murmansk Abstract. The data of registration system of geomagnetically induced current (GIC) o f the Polar Geophysical Institute and Kola Scientific Center in power lines of Kola Peninsula and Karelia, data o f IMAGE magnetometers was used for the investigation the characteristics of the geomagnetic field variability. The technique of the vector representation of the geomagnetic field variations shows the great variability of the dB/dt according to ЛВ for the magnetic storm 17 March 2013. The quantity estimation with using the so named RB parameter confirm that the geomagnetic field variation occur as in value as in direction. These results can’t be explained the simple model o f the prolonged ionosphere current and show the importance of the accounting of the small-scale currents structures for the GIC calculation. The ionosphere currents fluctuate not only in E-W direction but also in N-S direction. So the GIC are dangerous also for the technological systems extended in N-S direction. 1. Introduction. One of the most significant factors of space weather for terrestrial technological systems are elcctric geomagnetically induced currents (GIC) in the surface layers of the Earth causcd by abrupt changes o f the geomagnetic field. GIC are dangerous for extended high-voltage power lines, railway equipment, marine and ground communications cables, telephone and telegraph lines [Pirjola et al., 2005]. The most intense currents (up to hundreds of amperes) and fields (more 10 V/m) are excited at auroral latitudes during magnetic storms and substorms [Lanzerotti, 2001]. Induced currents cause saturation, overheating and even damage of the high-voltage transformers. Geomagnetic variations with dB/dt>l nT/s were found to be sufficient to induce GIC in Finnish power lines about several A and higher, and variations with dB/dt>40 nT/s caused failures in the operation of Scandinavian power lines [Viljanen, 1997]. In this paper we examine the contribution of geomagnetic disturbances during two moderate geomagnetic storms into enhancements o f GIC recorded by the GlC-recording system and IMAGE array o fmagnetometers. Predominantly geomagnetic field disturbances are supposed to be oriented in the N-S direction, and produced by the E-W ionospheric currents. Thus, such disturbances seemingly would not induce any significant GIC in a latitudinally-oriented system. However, during magnetic storms GIC in power systems were quite significant. 2. GIC and magnetic field recording systems. The system to monitor the impact o f GIC on power lines has been deployed in 2010 at Kola Peninsula and Karelia by the Polar Geophysical Institute and Center for Physical and Technical Problems o f North's Energetic [Sakharov et al., 2009]. The system consists of 4 stations at "Kolenergo" company power line 330 kV and a station at power line 110 kV. Each station records a quasi-DC current in dead- grounded neutral of autotransformer in power line. Information about GIC is important not from practical point of view only, but from a fundamental scientific view, revealing a fine structure of fast geomagnetic variations during storms and substorms. To characterize the geomagnetic field variations we use data from IMAGE magnetometers located in the vicinity of GIC recording stations. 3. Characteristics of the geomagnetic field variability. To characterize the geomagnetic field variability in magnitude and direction the following characteristics have been applied. Vector diagram. The vector diagram technique presents in a concise form a time evolution o f the meridional profile of horizontal magnetic disturbances vector. For that, vectors of geomagnetic disturbances AB={AX,AY} for each station are plotted on the same plot as time sequence of vectors. This technique was used in [Fries-Christensen et al., 1988] for the analysis of travelling convection vortices. The same diagram can be constructed for the equivalent ionospheric current J and vector derivatives dB/dt={otX,5tY}. The current J is related to AB as follows АВ=(2я/с)[1хп], where n is the normal to the ground surface. RB parameter. This parameter shows docs a vector field experience fluctuations in magnitude or in direction? For the 2D case B(t)={AX,AY} the parameter RB for a time series of N samples is determined as follows [Du et al., 2005]: 34