SK380792A3 - Indicator lightning arrester defects - Google Patents

Abstract

It comprises two opposed electrodes (1, 2) united, on the one hand, in series by a low-voltage varistor (3) through which pass possible lightning waves and, on the other hand, in parallel via a resistor (7) which does not react during a lightning wave but rises in temperature during passing of the current generated by the grid in order to at least partly destroy a sleeve (11) surrounding the indicator.

Description

Lightning fault indicator

The present invention relates to a device that operates as an indicator of a fault or short circuit and is to provide lightning arresters mounted on high or medium voltage power lines.

Devices of this kind are known e.g. a device as described in FR-A-2603418 (FERRAZ) having a built-in visual signal to provide a perfectly visible indication of a possible lightning arrester to which the device is mounted.

Such a device is provided with an elastically deformable tape, one end of which is connected to the fuse being released as soon as there is a fault in the surge arrester associated with the device. The means for releasing the surge arrester depends on an electric filter consisting of two parallel windings, one of which is inductive and is designed to override the current caused by a high di / dt lightning discharge, the other winding being resistive and avoiding eventual short-circuit current. pass through the induction line in series with the safety wire, the melting of which then releases the indicator.

However, this indicator is less sensitive because it does not exceed 70 amps. In addition, the electric filter system requires a self-induction value that can be very difficult to realize on an industrial scale and at low cost. Finally, the principle of current selection on the basis of their time course exhibits the disadvantage that, in the event of a lightning discharge, important flux currents are not passed through the fuse wire. However, the duration of the lightning discharge is not sufficient to break the fuse wire; however, the metal may premature aging if the lightning discharge is frequently repeated.

The improvements object of the present invention are to eliminate these disadvantages and to enable the lightning arrester fault indicator to be implemented, which is actuated by the function of the intense current generated in the mains after a short circuit in the lightning arrester.

A defect indicator according to the invention is defined in claim 1.

This indicator has two opposing electrodes, which are connected to the gloom on the one hand by a device characterized by a non-linear voltage such as a spark gap or a low voltage varistor and through which lightning discharges pass, and on the other hand has a parallel resistor which does not the temperature of which rises when the current generated by the power line is passed and thus at least partially breaks the sheath surrounding the indicator in the event of an accidental short-circuit of the lightning arrester connected to the dimmer of the indicator.

According to a further variant of the invention, an increase in temperature from the pore can break this resistance and cause the elastic tape to be punched out, the ends of which are connected to said resistance.

With reference to the accompanying drawings, in which an exemplary embodiment of the invention is given, a better understanding of the invention and its features and advantages is provided by:

Fig. 1 is a longitudinal section through an indicator according to the invention

Fig. 2 is a cross-sectional view of the line II-II (Fig. 1)

Fig. 3 is an electrical diagram of a fault indicator according to the invention

Fig. 4 is a detailed perspective view of one embodiment of the invention

In Figure 1 and 2 show a first embodiment of an inventive fault indicator consisting essentially of two electrodes .1 and 2, preferably cylindrical, is provided between the varistor rter low voltage _3f linked by two spacers 4 maintain good contact between the electrodes and varistor. The three elements are assembled by means of an insulating pipe 5 with a vertical groove in such a way that an inverted letter C appears in the cross-section (FIG. 2). Tube 5 is connected to electrodes 1 and 2 by spacers 6.

It should be noted that instead of the varistor 3, spark gaps with circular electrodes or any other non-linear voltage device may be used.

The resistor 7 branches in two conductors 8 and 9 to the two wires 1 and 2 and is located in the tube 5a of the pipe 5. The whole of these elements is provided in a form which allows overlapping of the external sheath 10 made e.g. made of silicone elastomer. The resistor 7 touches one of the outer pumpkin sheaths 10 of the ducts of water, which we will explain below.

Around the sheath 10, a tubular elastomeric sleeve 11 is provided under tension, the placement of which is made possible by elastic extension. The sleeve 11 is preferably colored.

The electrode 1 is branched by all suitable means e.g. conductor 12 (FIG. 3) to the surge arrester 13, while the electrode is connected to ground by cable 14 (FIG. 3).

The function is as follows: in the event of a lightning discharge, an intense peak value is discharged into the earth by passing through the varistor 3, the current discharged to the resistor 7 does not cause a noticeable overheating of the resistance due to the short duration of the lightning discharge.

Conversely, if the lightning arrester 13 is damaged for some reason, the current generated by the mains is maintained until the mains protects. Thereafter, an overheating of the resistance is sufficient to melt the housing 11 relative to the proximity of the resistance and the housing. Thus, each operator can see that the fault indicator has worked (the housing 11 will be lost) in such a way that the respective lightning arrester is now out of service.

The variant of FIG. 4, the housing is in the form of a tape 11 'which does not occupy the entire circumference of the housing, and a space 15 is formed between its ends. Each end of the tape 11' is provided with a metal clamp 11a, 11b and a respective end attached thereto. resistor 7, which thus represents a means for holding the broken linen tape in place. The terminals 11a and 11b are connected to wires 8 and 9.

When the network emits a current corresponding to the respective defect indicator after the lightning arrester short-circuit, the current intensity leads to the expansion of the resistor 7, which thus releases the two ends of the tape 11 'which are to be. due to its elasticity it separates from the defect indicator. Thus, the operator can visually state that the tape is wrong and inferred that the lightning arrester is out of order.

Thus, a fault indicator has been developed which is particularly advantageous in accordance with practice requirements and which, in particular, allows virtually all leakage current from the surge arrester 13 to pass from the port 7 so that the varistor will not age in normal operation.

It should be noted that increasing the temperature of the resistor 7 can act on the signaling circuit remotely, which makes it easier to recognize that the fault indicator has been violated.

Claims (3)

1. A lightning arrester (13) fault indicator located on a high or medium voltage line electric traction line, characterized in that it consists of two electrodes (1,2) connected on one side to the shade by a device (3) characterized by a non-linear voltage such as varistor or spark. and, on the other hand, a resistor (7) which is not connected to the lightning discharge, but whose temperature rises as the current generated by the power line flows as a result of the discharge and guarantees the release of the visual signaling element (11, 11 ') surrounding the housing (10). equipment due to remelting. Indicator according to claim 1, characterized in that the resistance (7) retains both ends of the elastic strip (11 ') arranged around the housing (10). An indicator as claimed in either of claims 1 and 2, characterized in that the temperature increase of the resistor (7) acts on the signaling circuit remotely.