Disconnecting Switch

disconnecting switch

[‚dis·kə′nek·tiŋ ‚swich]
A switch that isolates a circuit or piece of electrical apparatus after interruption of the current. Also known as disconnector.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.

Disconnecting Switch


a high-voltage switching device used to disconnect and switch individual sections of electrical networks when the sections are not carrying a current. It produces a directly visible break in the electrical network. In high-voltage bus-and-switch structures disconnecting switches are used primarily to ensure safety during maintenance and repair work on the disconnected sections. In some cases, moderate currents are interrupted by means of disconnecting switches—for example, the magnetizing currents of low-power transformers or the currents of short, unloaded lines. Disconnecting switches are also used for sectionalizing buses and switching electric lines from one bus system in a bus-and-switch structure to another.

A disconnecting switch consists of movable and stationary contacts mounted on insulators. A movable contact is actuated by using an insulator to connect it with a conductor. Disconnecting switches are classified according to the type of installation (indoor or outdoor), the number of poles (for example, single-pole or three-pole), and the method of control (manual or remote). In electrical networks having a voltage ≥ 110 kilovolts, the movable contacts of the disconnecting switches used are of the pantograph type, and the stationary contacts are mounted on the conductors (buses). To avoid erroneous operation, disconnecting switches are provided with mechanical, electrical, or combination interlocks that prevent the opening or closing of the disconnecting switch when the associated high-voltage switches are closed. Disconnecting switches must be capable of passing the rated load current for a long period. They must have excellent thermal and transient stability when passing short-circuit let-through currents.


Afanas’ev, V. V. Raz”ediniteli peremennogo toka vysokogo napriazheniia. Moscow-Leningrad, 1963.
Chunikhin, A. A. Elektricheskie apparaty. Moscow, 1975.


The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.
References in periodicals archive ?
Key ABB products to be supplied include power transformers, high-voltage switchgear rated at 230 kV (kilovolt), 138 kV and 69 kV, circuit breakers, disconnecting switches, instrument transformers, surge arrestors, as well as medium-voltage equipment and auxiliary systems.ABB will also install a substation automation system compliant with the global IEC 61850 communications standard, and equipped with the latest protection and control products.