SU843077A1 - Device for current protection of attachment - Google Patents

Description

(54) DEVICE FOR CURRENT PROTECTION OF CONNECTION

The invention relates to the field of power supply to consumers, in particular, to relay protection devices. A device for disconnecting a defective part of the electric power supply line is known, comprising a magnetic amplifier, positive feedback and bias coils, capacitors, a time relay unit, an output unit Tlj. The drawback of the device is the insufficient speed and complexity of the device. A device for isolating a damaged area is known, containing the connected coils of the main current relay and the primary winding of the transformer connected to the secondary windings of current transformers, the primary windings of which are connected to the protected power line, to which the rectifier bridge is connected; connected through zamknayuschy contact of the main current relay connected in series the first resistor and the first capacitor, the control element l of the protected line with NbiKaiooHM and once contacts, connected in series the second resistor and the second capacitor, between the common connection point and diagonal of the rectifying bridge are connected in series the disconnecting contact of the control element of the protected line and the output execution unit connected in series to the third resistor and memory element, one output of which is connected to the diagonal of the rectifying bridge G2. The drawback of the device is the presence of a large number of contacts and the use of a polarized relay, which complicates the device. The purpose of the invention is to simplify the device. The goal is achieved by the fact that a device for current protection of the connection containing serially connected windings of the main current relay and the primary winding of the transformer connected to the secondary windings of current transformers, the primary windings of which are included in the protected power line of the specified transformer is included in the secondary winding of the transformer included the bridge, to the output of which is connected through the contactors of the contact of the main current relay, the series-connected first resistor and the capacitor / control unit of the protected line state with the closing and disconnecting terminals are connected in series, the second resistor and the second capacitor are connected between the common connection point and the diagonal of the rectifier bridge and the disconnected contact of the control unit of the protected line state and the output an executive unit connected in series to a third resistor and a memory element, one output of which is connected to the diagonal of the rectifying bridge, is additionally introduced The fourth and fifth resistors shunt the second capacitor and the memory element respectively, the second output of the latter is connected to the common connection point of the first resistor and the first capacitor through the third chopper and the disconnecting contact of the main current relay and one of the terminals of the fifth resistor is connected via a closing contact of the control element of the state of the protected line to one of the terminals of the second resistor, and the element pgatti is made in the form of a third capacitor, and the control element of the operating State of the line is in the form of a winding of an additional current relay connected in series with the winding of the main current relay. FIG. 1 shows a circuit diagram of a device for overcurrent protection of the connection; in fig. 2 shows an example of using this device in a network with a large number of connections. The device for current protection of the connection contains current transformers 1 and 2, the primary windings of which are included in the circuit of the protected power line, the secondary windings are connected in series with the main current relay 3 and the primary winding of the transformer 4, to which the secondary winding of the rectifier bridge 5, to the output of which is connected via a closing contact b of the main current relay 3, series-connected resistor 7 and capacitor 8, element 9 of the control of the state of the SPARED line with the wet contact 10 and the disconnecting contact 11, series-connected resistor 12 and capacitor 13, between the common connection point and diagonal of the rectifying bridge 5 are connected successively connected disconnections of the contact 11 of the working condition control element 9 and the output executive unit 14, The resistor 15 and the memory element 16 are jointly connected, one output of which is connected to the diagonal of the rectifying bridge 5, the resistors 17 and 18 shunting the capacitor 13 and the memory element 16, respectively, Naturally, the second output of the last i through the resistor 15 and the disconnecting contact 19 of the main current relay 3 is connected to the common connection point of the resistor 7 and capacitor 8, the common connection point of the second output of the memory element 16 and one of the terminals of the resistor 18, through the closing contact 10 of the element 9 monitoring the operating state of the protected line is connected to one of the terminals of the resistor 12, the memory element 16 being designed as a capacitor, and the operating condition monitoring element 9 being in the form of an additional current relay winding. When using this device in a network with a large number of connections, it is installed on each connection. The device 20 for current protection of the connection is connected to the current transformers 1 and 2 of the connection and acts to disconnect the low-responsible consumer 21 through a linear switch 22. The protected connection is connected to the main power line 23 supplying the responsible consumer 24. Power line 23 is connected to the substation switchgear 25 through the main switch 26 and current transformers 27 and 28. To the secondary circuits of current transformers 27 and 28, overcurrent protection is connected to you time delay 29, act to turn off the main switch 26. Turning on the switch 26 is affected by the device 30 two-time automatic reclosing (AR). Device for current protection connection works as follows. In the normal mode of operation, the network from switchgear buses 25 through the main switch 26 and power line 23 supplies power to the responsible consumer 24, and through the linear switch 22 to the low-responsible consumer 21. In the secondary circuits of current transformers 1 and 2 current flows through the windings 3 and 9 current relays, contact 6 of the main current relay 3 is open, and the contact 19 is closed, contact 10 of the additional current relay 9 is closed, and contact 11 is open. The output of the execution unit 14 is in the initial state. If a short circuit occurs at the connection at the point K |

the current in the secondary circuits of current transformers 1.2 and 27.28 increases. Triggering overcurrent protection 29 starts counting the time delay. At the same time, device 20 for current protection of the connection is started up. The main 3 and additional 9 current relays, through the closing contact 6 of the main. the current relay 3 and the resistor 7 charge the capacitor 8, the full charge time of which is equal to the time delay of the maximum current protection 29. When the maximum current protection 29 is activated, the main switch 26 is disconnected, which leads to de-energization of the line 23, the responsible consumer 24 and a low-responsible consumer 21. In this case, the windings of the main 3 and additional 9 current relays of the device 20 for connection overcurrent protection are de-energized. Through the opening contact 19 of the main current relay 3 and the resistor 15, the capacitor 8 is discharged to the capacitor 16 on which the voltage is set, i.e., half the voltage on the capacitor 8. At the same time, the automatic reclosing unit 30 is started.

During the time of the dead time: the short circuit on the connection self-destructs, the AR unit 30 turns on the main switch 26. At the same time, the device 20 for current protection of the connection returns to its original state and capacitor 8 and 16 are discharged through the trip contact 19 of the main current relay 3 resistor 18.

In the case of a stable short circuit, the AR unit 30 turns on the main switch 26. This triggers the main 3 and additional 9 current relays. The capacitor 8 is charged to full voltage through the closing contact 6 and the resistor 7. The capacitor 16 through the closing contact 10 of the additional current relay 9 and the resistor 12 discharges to the capacitor 13. The capacitor 13 is set to a voltage equal to half the voltage on the capacitor 18.

After a time delay, the maximum current is triggered by the ion 29 and turns off the main switch 26.

The windings of the additional 9 and main 3 current relays are de-energized and the capacitors 8 and 16 are discharged to the resistor 18. The capacitor 13 raer is fired through the soaking contact 11 to the executive unit 14, which strikes the switch and, therefore, the damaged connection. : The proposed Device allows to simplify the device for overcurrent protection of the connection.

Claims (2)

1. The patent of Japan 52-18383, cl. H 02 H 7/26, 1977. 2. Electric stations, 1977, 11, p. 68-69. 44 " Jd ig go -