SU1330672A1 - Zero phase-sequence current transformer - Google Patents

Abstract

The invention relates to electrical engineering and is intended for use in three-phase networks with high load currents in single-phase earth fault protection devices. The purpose of the invention is to reduce the error V V, which increases the range of operating currents. The device comprises an annular core 1, a secondary winding 2 covering the core 1, the primary winding in the form of conductors 3 of a three-phase network, a ferromagnetic hollow cylinder 4 located in the core window and the covered short-circuit coil 5 of the brush. The magnetic circuit can be shielded using an armored shield 6. When a leakage current appears in the core, a magnetic flux is generated and, accordingly, the EMF in the secondary winding is proportional to this current, since the total current flowing through the conductors of the network 3 and in the short-circuited loop 5 does not include unbalances due to the asymmetry of the device. 1 il. 1C (L with OO o O)

Description

one

The invention relates to electrical engineering and is intended to be used in single-phase fault protection devices on three-phase networks with high load currents.

The purpose of the invention is to reduce errors, which allows to increase the range of operating currents.

The drawing shows the device, a general view. The device comprises an annular core 1, a secondary winding 2 enclosing the core, a primary winding in the form of conductors 3 of a three-phase network, a ferromagnetic hollow dilil 4 located in the core window and covered by a short-circuited coil 5 of high electric

water material. The magnetic core can be shielded by

armored screen 6.

A reduction in the filter errors is achieved by the fact that the short-circuit coil 5 provides demagnetization of the ferromagnetic cylinder 4, maintaining its high magnetic permeability (preventing saturation) and shielding skinny properties. Ferromagnet cylinder 4 shields the core from the fields due to the 1Symmetric placement of the phase

Editor M. Kelemesh

Compiled by V.Gerih Tekred M. Khodanych

 / e/. Circulation 698 Subscription

VNIIPI USSR State Committee

for inventions and discoveries 3035, Moscow, Zh-35, Raushsk nab., 4/5

Production and printing company, Uzhgorod, Projecto st., 4

five

30672

the power lines of the network with respect to the central axis of symmetry of the core, the unevenness of laying the turns of the secondary winding around the perimeter of the core, etc.

When a leakage current (zero-sequence current) appears in the core, magnetic flux is generated and, accordingly, the EMF in the secondary winding is proportional to this current, since the total current flowing through the conductors of the network 3 and in the short-circuited loop 5 and through the loop It does not include unbalances due to asymmetry of the device.

ten

15

Fore

at l and

the invention

The current transformer of zero succession of the aptice containing a ring core on which its secondary winding is installed, a ferromagnetic hollow cylinder placed in the core window, through

KOTopbiii passes the conductors of the three-phase network conductors, characterized in that, in order to reduce the error, the current transformer is equipped with

solid short-circuited coil of high-conducting material, covering the ferromagnetic zero cy.chpndr.

Corrector S.Cherni

Claims (1)

Claim A zero-sequence current transformer containing a ring core on which a secondary winding covering it is mounted, a ferromagnetic hollow cylinder paved in a core window through which phase conductors of a three-phase network pass, characterized in that, in order to reduce errors, the current transformer is equipped with 30 solid a short-circuited coil of highly conductive material covering a ferromagnetic hollow cylinder.