DE374713C - Device to prevent strong earth currents in the event of double-pole earth faults in AC systems with a lightning cable - Google Patents

Description

In AC systems, a lightning rope is often attached to the masts of the high-voltage lines laid, which is earthed via the mast, or a rope is also put directly into the Earth laid. The charging currents of the lines also find their way back in such a rope, it also absorbs part of the earth current in the event of earth faults. The size of this part is in inverse proportion to ohmic

ίο and inductive resistance of the rope.

About the reaction of the currents running in the earth on nearby ones To reduce low current lines or the dangers of stepping on the ground in the To reduce the proximity of the lines in case of earth current, it is desirable that the lightning rope carries as large a part of the earth current as possible.

According to the invention this is achieved in that the phase lines and the lightning cable are connected at certain intervals by transformers whose windings are dimensioned and connected so that the Lightning rope absorbs a large part of the earth fault current.

Fig. Ι shows the arrangement of a three-phase network with a lightning cable, a, b, c are the phase lines, d the lightning cable, which is grounded by the masts or other earth lines at points e; f, g and h are the transformer windings in the train of the phase lines, i the transformer winding in the train of the lightning rope. In the event of a ground fault in the lightning cable, the winding i creates an additional electromotive force in the sense that the lightning cable absorbs a very strong current and thereby relieves the earth of the current.

Instead of using a common transformer for all phase lines, one can also arrange three single-phase transformer windings, as shown in Fig. 2. In the phase lines a, b, c are the windings f, g, h of the individual transformers, whose secondary windings i _a , ΰ, i _{c are} in the train of the lightning cable.

It is advantageous in the arrangement described that the lightning cable to the zero point of the main transformer can be connected, so that a favorable grounding of the zero point is achieved.

Claims (2)

P ATENT claims: 1. Device to prevent strong earth currents in the event of double-pole earth faults in alternating current systems which are provided with a lightning cable, characterized in that the phase lines and the lightning cable are connected at certain intervals by common transformers whose Windings are dimensioned and connected so that the lightning cable absorbs a large part of the earth fault current. 2. Modification according to claim 1, characterized in that special for each phase Single-phase transformers are used, which bring about the coupling with the lightning cable. For this purpose ι sheet of drawings.