DE1057227B - Method and device for insulation monitoring of single or multi-phase alternating current networks by means of direct current superposition - Google Patents

Description

JULK

For insulation monitoring for single or multi-phase alternating current networks by means of direct current superimposition if only one single device is connected to the network, the measuring DC voltage is connected to the Imprints or imprints the network. Any other similar device would namely display the former strongly affect. Now, however, there is often a desire to also measure the overall insulation to be able to make distant points. Additional display instruments were used for this purpose, which are connected to the mother device via special measuring lines. The laying of this However, measuring lines are perceived as a disadvantage.

The invention is based on the object of simultaneous insulation monitoring by means of direct current superimposition in two or more distant places without laying additional To enable measuring lines between the individual measuring points. This task is according to the invention has been solved in that the direct current superimposition is applied simultaneously to each of the one another remote points of the network are carried out by DC voltage generators with associated devices that measure the insulation value and that the individual monitoring devices with regard to the level of DC voltage, internal resistance or Relay sensitivity in accordance with the branching of the in the event of an insulation fault via the fault location flowing measuring direct current measured on the measuring points located at a distance and with common Operation can be adjusted to the same display or to the desired response values. Man at the same time receives the lower sensitivity compared to the individual devices, which is advantageous for certain networks. The prerequisite for the proper function of the devices is that they are always on at the same time the network work and that, if one for the purpose of testing or the like is switched off, an equivalent in its place Phantom kicks. For this purpose, if one of the devices is disconnected from earth or from the network, a for the other devices operate in the same way as the otherwise disconnected device be switched on.

To carry out the method according to the invention, two or more are expediently with regard to Superimposed DC voltage and internal resistance used approximately the same devices that are calibrated together.

Since it is cumbersome with regard to superimposed DC voltage and internal resistance of the To achieve perfect equality between different monitoring devices, it is advantageous to use the Mefi path each device to switch an additional valve, which is only permeable in the direction of the measuring current, but Procedure and establishment

for insulation monitoring

of single or multi-phase

AC networks
by means of direct current superimposition

Applicant:

Dipl.-Ing. Walther Bender,
Grünberg (Obhess.), Frankfurter Str. 28

Dipl.-Ing. Walther Bender, Grünberg (Obhess.),
has been named as the inventor

a current flow in the opposite direction, the z. B. by voltage differences of the individual devices can be caused, locks off. This avoids equalizing currents, especially with a healthy network flow through the instruments that could cause a misleading rash.

The invention will be explained in more detail using two different exemplary embodiments.

1 shows a two-pole contact line system which is monitored by two insulation monitoring devices operating with an applied direct voltage. Two single-phase transformers 1 each work via a circuit breaker 2, which has a shunt release 3, on the contact lines 4, 5 of a mine railway. An insulation monitoring device is connected to each transformer 1 by means of an applied direct voltage, which generates a direct voltage via the transformer 6 in the rectifier 7, which is stabilized with the aid of the stabilizer 8 and which is connected to the network with one pole via the resistors 9, 10 which are the same among themselves, while the other pole is connected to earth via the display instrument 11, the relay 12 and one pole of the test switch 13. The test switch 13 allows the measuring branch to be disconnected from earth and the function of each device to be checked via the test resistors 14 and 15, respectively. One likes to use two P ruf positions, one of which simulates a relatively high-resistance insulation fault

909 510/216

Claims (1)

3 4 although the display instruments 14 and 11, respectively, remain in the same reactive conditions. In both but not the relays yet. In the other test embodiments, it is the test switch that resistance is chosen so low that also the relay _m j _th i _nem pole turns on the replacement member. One can 12 responds and the main switch is triggered. Of course, if necessary, others too, e.g. B. the im During the test positions of switch 13, 5 mains use existing circuit breakers to the other pole of the same a substitute connection via when disconnecting a power supply unit from one of the insulation the resistor 16 to earth, so that the lationsüberwachungsgeräte such a substitute element to switch on the same type lying in another transformer station. Insulation monitoring device no change in the two display instruments 11 in FIG. 1 learns of his ad. The normally open contact of the relay 10 and 2 can also have two different calibration divisions 12 is used to trip the shunt release 3 received, one of which is for working together in the event of a major insulation fault. So determined by two insulation monitoring devices If there is little difference between the two, the insulation is over and the other for the case that one device is alone monitoring devices do not work in opposite directions on a network. The Equalizing currents from one to the other instrument 15 trigger the relay 12 in a known manner can, the valve 17 is still made in the measuring path bar. Furthermore, the overbuilt. monitoring devices can also be designed so that they 2 also shows a two-pole contact line, optionally for use as the sole over-installation, which is also protected by two insulation monitoring devices or in conjunction with one or more devices, which, however, work with several other monitoring devices that can be changed over to measuring DC voltage. Again, two are working here. This is e.g. B. to carry out so that a device, single-phase transformers 1 is intended for cooperation with 0 to η other devices circuit breaker 2 with the shunt trip 3, η suitable replacement members (or on the overhead lines 4,5. DieIsolationsüberwachungs- replacement member with η different settings) Entgeräte work in such a way that 25 of the two holds. When working with χ similar hazard lines starting from the resistors 6, then in each device η-χ replacement members, the half-wave rectifiers 7, the relay 12 and the measuring path (or an equivalent set replacement insulation meter 11 formed via the member) are switched on. Both circuits can also lead one pole of the test switch 13 to earth. If there is no continuous display of the insulation resistance insulation faults in the network, a current flow occurs in the known state, that is to say without the display instruments 11, and is guided in the moving coil. You can also provide another relay instrument 11 for a measurement of the insulation fault, which allows when the insulation resistance drops. The relay 12 is dimensioned in such a way or a signal initially triggers a signal, which is then set so that in the event of insulation faults of certain relays 12 it only responds to the size and triggers the circuit breaker 2 when the fault is more advanced. switches off by means of the shunt release 3. Both also more than two insulation monitoring devices are combined in this way. If you ensure that they are calibrated, they are calibrated together on each side of the network and all of them simultaneously indicate the total insulation value against earth. The one lying on the net.
Test switch 13 in turn allows the measuring branch, 40 PiTFUTJuspnftcHR
which contains the relay 12 and the insulation meter 11, to be separated from the earth and a first method for insulation monitoring of the two test resistors 14 or 15 to a single or multi-phase alternating current network, to set the function of the device Check mine railway systems with double. During the test positions of the switch 13 45 contact line, by means of direct current superimposition, the right part of the latter establishes an equivalent measuring path over which the resistors 6a, the rectifier 7a and the remote points of the network insulation resistance 16 to earth are connected to two or more of each other at the same time, so that the display of the monitoring is carried out, characterized by other insulation monitoring devices unchanged that the direct current superimposition is maintained. 5 ° simultaneously at each of the apart The insulation monitoring devices are each lying down in the network by means of equal connected to the circuit breaker 2, so there are voltage generators with associated insulation Always both on the catenary, even if one of the devices measuring the value is carried out Circuit breaker is disconnected. and that the individual monitoring devices The invention is not limited to the illustrated example of the level of the DC voltage, internal games, rather various resistance or relay sensitivity according to dimensional modifications and other embodiments in the branch of the insulation framework of the invention are possible. As self-error over the fault location flowing Meßgleichverständlich can also be in multi-phase networks such current measured ⁶ ° to the measuring points remote from one another matched insulation monitoring and find devices with common operation application. The substitute element that is set for response values that are switched on for the same display or for the desired one of the devices when it is disconnected,
is, consists in the embodiment of FIG. 1. 2. The method according to claim 1, characterized only by a resistor 16, characterized in that when disconnecting one of the devices management example according to FIG one for the remaining resistor 16, the resistors 6a and the equal devices in the same way as the other downsizing 7 c. So you can see that there is a more or separate device working resistance replacement switch less complete replication of the actual device is switched on. Insulation monitoring device can be. Relevant 3rd facility for carrying out the is only that for the other device, if possible, the 7 ° drive according to claim 1 or 2, characterized