, PJSC “ROSSETI” Chief Engineer




Interview with



1502 MPEI lyceum principal









, D.Sc., Professor, CJSC “MC CEU”



IDGC of North-West, PJSC







0.38 kV power networks are operated in the unbalanced state, where power losses in the net- works are double and even higher than in the balanced state. For the purpose of power losses reduction, it is recommended to use load-balancing filter device containing three capacitor banks and a transductor amplifier. The operating winding of transductor amplifier is connected between neutral conductor of the network and capacitor banks neutral point. This operating winding and three capacitor banks are connected in series and configured to voltage resonance. As such, electric circuit has a small active resistance and provides load shunting. Due to a low zero sequence resistance of load-balancing filter device, it will shunt zero-sequence currents in the network, reducing line and transformer power losses and improving power quality. Some results concerning experimental investigation of load-balancing filter device are given. The investigation was executed on 0.38 kV three-phase network physical model at the Power Engineering and Electric Equipment Department of SPb SAU. Transmission line and transformer power losses research were carried out through criterion of power losses caused by current unbalance. The criterion was developed at the department of SPb SAU. According to research, in the most heavy loaded unbalanced state transformer power losses criterion is about 8 times less when connecting load-balancing filter device to the load bus (in the case of the network is close to nominal condition). Under the same conditions transmission line power losses criterion is about 3.5 times less.


three-phase power network, power losses, power quality, load-balancing filter device, power losses reduction, power losses criterion, experimental investigations


Smolenskenergo, IDGC of Centre, PJSC division


Yakshina N.V.




“Tetravizhn”, LLC


Smolentsev M.V.






Electric current flow in the energized transmission line conductors generates an alternating magnetic field. In its turn, the magnetic field can produce electromotive force (EMF) when crossing conductors of transmission line under construction or repair. The induced voltage hence occupational safety depend on strength of current in the energized transmission line, distance between conductors of energized and repaired lines, as well as the length of wires and their relative position.

This article presents a method for induced voltages calculation in the wires of deenergized overhead lines which are located close to 110 kV and above overhead lines in operation. The method is based on the air core transformer theory (air core transformer is a transformer without ferromagnetic core). The method assumes that primary winding of transformer is a wire of an energized line and secondary winding is a wire of a parallel deenergized line.

Keywords: induced voltage, air core transformer, EMF of mutual induction, Carson’s formula



Dmitriev M.V.


Russia has already accumulated experience in the design, construction, and operation of XLPE cable lines. Apart from an application of this cable type to typical power supply schemes, group of engineers began to consider the possibility of using XLPE cables for more ambitious tasks as long AC cable lines construction. The article represents the possibility of long AC cable lines development.

Keywords: cable line, XLPE cable, power transmission, active power, reactive power, long transmission lines


Poleshchuk S.I.


The article analyzes thermotechnical calculations of cables in existing regulatory documents. The mistakes made when translating these documents into Russian are shown. The formula for underground cables permissible current load used in regulatory documents is analyzed when partial drying of the soil. The inconsistency of this formula to the physical processes of heat dissipation in cables is shown. A formula for permissible current loads for three single-core cables laid in ground cable trays is proposed.


electric cables, current rating, thermal resistance, ambient temperature


Expert opinion





Voloshin A.A., Voloshin E.A., Blagorazumov D.O., Gracheva N.P., Tyapkin N.V., Charugina A.V.


Optimal structure of Local Area Network (LAN) synthesis algorithm and its software implementation with Python programming language have been developed in order to form LAN structure for process bus. Taking into consideration conducted investigations, the conclusions on suitability of different architectural options application for digital substation relay protection and automation have been made.


relay protection and automation, IEC 61850, local area network, digital substation, technical and economic assessment


Zhukov A.V.



Interview with Dolgov A.S., JSC “UNECO” Head of relay protection and automation department


“ElektroKontsept”, LLC



“Izolyator” Company






“Elektropribor”, JSC


Interview with Cherenkov I.V., director general of “RTK-ELEKTRO-M” plant


“Rokstek RU”, LLC








Elpidiforov V.Yu.




Gvozdetskiy V.L.