SU928524A1 - Device for overvoltage protection of communication line with remote power supply - Google Patents

Description

The circuit can be shorted by a high-voltage fault for a long time (up to 500-800 ms). If such a malfunction is still permissible in the circuits intended for the transmission of electrical energy, then in the circuits of communication sealed with 4-channel equipment, this can lead to a remote power supply that automatically shuts off after 4D, ms, t. e. to emergency consequences m.

The aim of the invention is to reduce the time for switching off the arrester after performing protective functions.

This goal is achieved by the fact that the device for protection against overvoltages of communication lines with remote power supply, containing a gaiter connected via the breaker contact of the executive relay between the protected line and ground, the transistor, the zener diode and resistors, additionally contain an intermediate relay, two outputs, three a capacitor and a current transformer, the primary winding of which is connected to the arrester circuit, and two secondary transformers are connected to the rectifier inputs, in parallel with the output of one of which a capacitor is connected, with tablithron and through a resistor, the base-emitter junction of the transistor, and a capacitor are connected in parallel with the output of another processor and a coil of the intermediate relay, the collector-emitter junction of the transistor between the base and the collector of which is connected to a resistor, and a series-connected resistor and a capacitor are connected between the source line and the ground in parallel with which through the closing contact of the intermediate relay is connected the winding of the executive relay.

The drawing shows the layout of the device.

The device contains an arrester 1, connected via disconnection contact 2 of the executive relay 3 between the protected line 4 and the ground. A current transformer 5 is connected to the circuit of the arrester 1, the secondary windings of which are connected to the inputs of the rectifiers 6 and 7, in parallel to the output of the rectifier b are connected a capacitor 8, the Zener diode 9 and through the resistor 10, the base-emitter junction of the transistor 11, and parallel to the output of the rectifier 7 are connected. the capacitor 12 and the coil-emitter junction of the transistor 11 between the base and the collector of the transistor 11 are connected through the coil 13 of the intermediate relay 11. A resistor 15 and a capacitor 16 are connected in series between the protected line 4 and the earth, which are connected in parallel via the bushing contact 17

Intermediate relay connected winding 3 Executive relay.

The device works as follows.

When the discharger 1 triggers, a current pulse passes through the contact of relay 2 and the transformer 5 winding, and induces an emf in the secondary windings, which is rectified with rectifier 6 and 7. The arcing voltage charges the capacitor 8 and serves as a locking the voltage in the transistor 11 circuit, after the current wave in the primary winding of the transformer is terminated, the 5-accumulated charge on the capacitor 8 is discharged through the emitter base junction resistance of the transistor 11 and the resistor 10. The zener diode 9 is designed to limit the voltage, Deployed between the emitter and the base, the alternating voltage of the other, secondary winding of the transformer 5 charges the capacitor 12, which is in the charged state as long as the blocking voltage is applied to the base of the transistor 11. After reducing the suppressing voltage, coming from the capacitor 8, the transistor 1 opens and the charging voltage of the capacitor 12 is applied to the winding of the relay 13 of the momentary relay, pin 17 of which connects the winding 3 of the operating relay to the capacitor 16. Accumulated by the capacitor 16 C The ard is discharged through the winding 3 and the executive relay is triggered, - a contact 2 in the circuit of the surge generator 1. The capacitors 16 charge circuit of the capacitor 16 from the voltage of the remote supply of such a wound so that when the executive relay winding is connected, the current flowing through the resistor 15 not sufficient to hold the relay core, so after discharge of the capacitor 16, the relay is reset. For the simultaneous shutdown of a large number of browsers connected to the cores of the protected line, only one device is used. The response time of the device can be adjusted by selecting the capacitance of the capacitor 8 and the resistor 10, which eliminates the emergency operation of the remote power protection devices. The time of setting the device to the working (on-duty) state is determined by the constant charge of condenser 16. After the charge of the capacitor 16 has finished charging, the current flowing through the charge circuit 15-16 is determined by the leakage current of the capacitor 16 and does not exceed 0.1 µA. Taking into account the significant amount of resistance 15 (more than 100 kSM), the charging circuit of capacity 16 does not introduce asymmetry into the working circuit.

The device improves the reliability of operation of communication lines with remote powering, by eliminating unjustified power cuts to the line when a discharged trigger fails.

Claims (2)

1. Mikhailov M.I. and others. The protection of communication structures against onacHtix and influences. References 1978, p. 98 2. The patent of Germany 2405671, cl. H 02 H 9/04, 1976 (prototype).