SU117721A2 - Saturated current transformer for differential with braking protection of power transformers - Google Patents

Description

Basically auth. St. L 95211 describes a saturable current transformer for differential braking protection of power multiwinding transformers. This current transformer contains a single window core, in the terminals of which there are additional oxides for accommodating current windings, and a protection relay is connected to the winding that covers the entire rod.

A distinctive feature of the proposed transformer is that short-circuited windings are mounted on the internal bridges of its rods. Such an embodiment of the transformer simplifies protection, since it does not require the summation of the secondary currents of all the windings of the power transformer and allows current equalization to be performed directly on the windings of the current transformer.

The drawing shows a schematic diagram of the proposed transformer.

The saturation transformer has a single window core /, in the rods of which there are additional windows 2 dividing each rod into two magnetic jumpers. The current windings 5 are superimposed on the external jumpers 4 rods and are adventurous to the current transformers 5 in the power transformer circuit 6. The short-circuited windings 7, which regulate the degree of braking, cover the internal jumpers 8 of these rods. The output protection relay 9 is adapted to the winding 10, covering one of the transformer rods.

In case of internal damage, the magnetizing forces (ns) of all the windings are directed in one direction, as a result of which a large working note is created and a protective relay 9 is triggered.