DE1076844B - Arrangement to achieve even power distribution in the secondary pipelines of single-phase furnace transformers - Google Patents

Description

GERMAN

It is common practice to feed large arc furnaces with three single-phase transformers for reasons of operational safety; a fourth transformer is kept in reserve to assist in the event of an incoming. Fault in one of the transformers to enable a quick replacement. In these single-phase transformers with secondary currents of up to 250,000 amperes and more, the secondary winding consists of a single turn in the form of a wide copper sheet, at the two ends of which vertically superposed pipe connections are provided for the power take-off (FIG. 1). In the individual parallel pipelines, as a result of the interlinking of the alternating fields, inductive resistances of different heights and, as a result, considerably different current loads arise. This phenomenon is undesirable in several respects and leads to difficulties, e.g. B. in the cooling of the pipe ladder. There are therefore various solutions that have become known for achieving uniform power distribution in high-current line systems of the aforementioned type. B. for three-phase transformers that adjacent individual conductors are magnetically coupled in pairs in such a way that all individual conductors or conductor groups of each pair are passed through an iron core in mutually opposite directions.

A magnetic chain formed in this way requires repeated cranking of the lines that is practically only feasible when using cable lines. But even then there are still considerable ones Difficulties, since the achievable radius of curvature depends on the conductor cross-section, see above that one is forced to use a large number instead of a few ladders.

The invention relates to an arrangement for achieving uniform current distributions in the Secondary pipelines of Emphasen furnace transformers, which differ from the previously known solutions characterized by particular simplicity. This is especially true with regard to normal use of easily coolable pipelines; here comes the progress made by the invention the known. Solutions is achieved in particular in appearance. The solution according to the invention assumes that there are four outgoing and four return lines vertically one above the other and the associated outward and return lines are each arranged horizontally next to one another. It is characterized by the Use of a magnetic chain with a pair of outward and return lines that belong together is passed through a recess of a laminated iron body and behind each one of these Lines to an adjacent line are higher

Arrangement to achieve
uniform power distribution

in the secondary pipelines
of single-phase furnace transformers

Applicant:

Siemens-Schuckertwerke

Corporation,

Berlin and Erlangen,

Erlangen, Werner-von-Siemens-Str. 50

Dipl.-Ing. Josef Scherber, Erlangen,
has been named as the inventor

or lower current levels and is continued with the latter as a new pair. The concept of the current level in the present sense is explained below. Run the associated outward and return lines different Partial currents, the differential current is caused by passing through the iron body Self-induction almost balanced. The relatively small residual current induces in both conductors an equally high inductive resistance, which in one conductor leads to an increase in potential and thus to a current reduction and in the other conductor to a potential reduction and thus to an increase in current leads. The end result is practically the same current distribution in all sub-conductors.

An embodiment of the arrangement according to the invention is particularly simple through its use a common iron body for all supply and return lines with four - ■ preferably on the side offset against each other - recesses. By shifting the recesses to the side, one achieves that the level change of the sub-ladder is carried out without crossing and without insulation of the pipe ladder can be.

To further explain the invention, reference is made to the drawing; it shows

1 shows the connection of the pipelines to the secondary winding of a single-phase furnace transformer, as mentioned above,

Fig. 2 is a schematic representation of the arrangement according to the invention.

In Fig. 1, a part of the secondary winding consisting of a wide copper sheet is shown with 1, the tube

909758/419

line connections are denoted by 2. Two pipelines are combined in terms of cooling flow.

In Fig. 2, the secondary winding of a single-phase furnace transformer is made of a wide sheet of copper denoted by 11; four vertically 5 superposed connection points for the Outward and return lines are indicated at 12-15 and 16-19. At 20 is a laminated iron body shown. It has four recesses that are laterally offset from one another and one above the other are arranged. Assume that without the measures according to the invention in the of the connection points 12 and 15 as well as 16 and 19 outgoing lines 35% and in the remaining lines 15% the total current load occur - the feed and return lines arranged vertically one above the other lie, ie at different "current levels" - according to the teaching of the invention, that of the connection point 12 outgoing line behind the iron body 20 in the 15% current level below continued. Accordingly, the outgoing from the connection point 13 and in one 15% current level lying line behind the iron body 20 in the overlying 35% current level continued. The two associated lines 16 and 17 are after the iron body continued at the same current level. The same procedure is followed for lines 14 and 15 or 18 and 19.

The required dimensioning of the iron body depends on the size of the deviations Partial flows. When it comes down to it, the iron expenditure for the iron body is as low as possible it is advisable to attach the iron body roughly in the middle between the transformer and the furnace, because in this case the effect of the iron body is over favored.

Depending on the local conditions, the iron body can also be placed directly on the furnace transformer or attached directly to the furnace. The arrangement directly on the furnace transformer enables a constructive combination with the transformer. The arrangement of the iron body directly on the furnace has the advantage that the connecting cables as outward and return lines through the Recesses of the iron body passed through and thus the dimensions, the recesses and thus the iron body can be chosen correspondingly smaller; in this case the connection is made Pipelines to the cable feeds seen from the furnace only behind the iron body.

The arrangement can also be designed so that the secondary winding of the furnace transformer is attached to the copper sheet two or more of the above four-fold conductor groups connected vertically one above the other and to each of the teachings of the invention are applied. When dimensioning the vertical Distance between the individual groups must be taken into account that none are used for power distribution disadvantageous mutual inductive influence of the conductor groups occurs.

Claims (2)

Patent claims: 1. Arrangement to achieve uniform power distribution in the secondary pipelines of single-phase furnace transformers with four outgoing and four return lines vertically one above the other and the associated outgoing and return lines are each arranged horizontally next to one another, characterized by the use of a magnetic chain, each with a related chain Pair of outward and return lines each led through a recess in a laminated iron body and behind it one of these lines to an adjacent line higher or lower Current levels and is continued with the latter as a new pair. 2. Arrangement according to claim 1, characterized by the use of a common iron body for all outgoing and return lines with four - preferably laterally offset from one another - Recesses. Considered publications:
German interpretative document No. 1 015 156. 1 sheet of drawings © 90Ϊ758Μ19 2.60