DE3140866A1 - ARRANGEMENT FOR PREVENTING MISTAKE PULSES OF A TOTAL CURRENT TRANSFORMER - Google Patents

Description

SIEMENS AKTIENGESELLSCHAFT Our mark Berlin and Munich VPA 8f P 3 1 6 8 DE

Arrangement to avoid false pulses of a summation current transformer

The invention relates to an arrangement for avoiding false pulses of a summation current transformer its secondary winding in residual current circuit breakers by means of shields inside the transformer core.

In the case of residual current circuit breakers, summation current transformers are used which have a relatively small difference between two have to record large nominal currents. In many cases, a number of secondary turns in the summation current transformer is sufficient for this from a few turns. It is therefore generally not possible to keep the secondary winding uniform to be distributed over the entire circumference of the toroidal core for the summation current transformer. However, as the primary conductor generally not be retained in any particular location in the ring opening of the transducer thus an assignment of the primary conductor and the primary winding to the secondary winding, which is only made up of individual Turns, freely selectable. It thus happens in practice that stray fields of the primary windings, their Total current is zero per se, are partially concatenated with the secondary winding of the converter. this can now mean a false pulse or a trip of the residual current circuit breaker, although none There is a fault current on the primary side of the converter. Also occur with very high currents, e.g. the switch-on rush of transformers or motors as the only consumer behind the converter, uncontrollable Stray fields that also cause false shutdowns. To isolate such problems is one

La 2 Syr / 05.10.1981

3,0866

v ° a 81 P 3 1 6 8 DE

Arrangement of the type mentioned above is known in which between the primary winding and the secondary winding of the summation current transformer s a thin-walled, magnetically conductive shield is provided. This arrangement has a substantial improvement of the false shutdowns with brought himself; However, they could with regard to the asymmetrical arrangement of the conductors within the summation current transformer not sure enough to avoid it yet.

2er invention is therefore based on the object of a To create an arrangement with which the false shutdowns, especially with very high currents, can be avoided even more safely without doing a significant amount In an arrangement of the type mentioned above, this is achieved in a simple manner by having at least one conductor in the area of the converter core encompasses concentrically. In order to dispense with special connection means for the concentric conductors to be able to, it is advantageous if the hollow cylindrical conductor parts with longitudinally extending, tapered connection projections are provided. The hollow cylindrical ladder parts are advantageously made of copper. The hollow cylindrical Conductor parts can for example be cast inside the toroidal core and the Extensions can be provided with screw connections, so that a three-wire cable can be connected without difficulty can be.

An exemplary embodiment according to the invention is described with the aid of the drawing.

Show it:

Fig. 1 is a sectional view through the erfindungsc; proper arrangement and
Fig. 2 is a side view.

3U0866

- / - VPA 8t P3 168DE

The primary conductors 3, 4 and 5 through which current flows are through the opening 1 of the annular converter core 2 passed through and the secondary winding 6 wound through. The primary conductor 5 can be used as a normal round conductor be designed, whereas the remaining primary conductors 3 and 4 are concentric with the primary conductor 5 as hollow cylindrical conductor parts are arranged. Longitudinal running, tapering connection projections 7 are used to connect the actual cables, which can be done in the usual way via screw connections. After inserting the hollow cylinder-shaped ladder parts and the primary conductor 5, these can be cast in the converter core 2 in the usual way, so that additional mounting measures can be omitted.

2 claims
2 figures

Claims (2)

- * - VPA 81 F 3 1 δ 8 DE Claims (1,) Arrangement to avoid false pulses of a Summation current transformer on its secondary winding ■ 5 residual current circuit breakers by means of shielding inside the transformer core, characterized that at least one conductor (3, 4) surrounds the other (5) concentrically in the area of the converter core (2). 2. Arrangement according to claim 1, characterized that the hollow cylindrical conductor parts (3, 4) with extending in the longitudinal direction, tapering connection projections (7) are provided "