Arc-suppression coils are designed to compensate a ground fault current in the power grid and are installed in power substations between the neutral point of power transformer, in case the star of star connection, or neutral point of earthing transformer in case delta connection and the ground. The terminal 1U of operating winding must be connected to the neutral point terminal 1N of the power or earthing transformer, and terminal 1N of arc suppression coil – connect with the earth. The ends of the additional windings 500V are brought out and marked 2U – 2N. Additional winding is used to force the active current component for selective operation of protective devices. In the conditions of short-circuit between phase line and the earth the compensating current flows through the arc suppression coil. The current – voltage characteristics of coils is very close to stright line, this is very important in operation. On the reactor are let out dual-core current transformer terminals 1S1 – 1S2 (core for protection) and 2S1 – 2S2 (measuring core). The reactor has an additional winding 100V used to measure marked as 3U – 3N, and the additional winding 1000V used to synchronize marked as 4U – 4N. The arc suppression coil is equipped with a system which uses Automated system of coil tuning as to obtain the output current in the range of 10% to 100% of the maximum current. Infinitely adjustable allows precise setting of arc suppression coil by using the movable part of the magnetic circuit. Changing the shape of the magnetic circuit causes the smooth change impedance of arc suppression coil.

Reactor Cores

Made of cold-rolled transformer plates covered with inorganic insulating material.

Reactor Windings

Made of electrolytic copper. The windings are wounded by the wire with a round section in enamel or profiled isolation. Between windings are channels required to ensure adequate air circulation and cooling. To compress the windings screw clamps were used, which do not allow to vibrate windings during work. Mounting and design of the windings provide very good dielectric strength, high resistance of lightning and a very good short circuit strength. To avoid surges, scheme of grounding components for all reactors has been developed.


Reactor has an system which uses an automatic coil tuning as to obtain the matched current in the range of 10 to 100% of the maximum current.


Capacity: 100-2700 kVAr

Voltage levels: 1-24 kV