SU1608771A1 - Communication line overvoltage protection device - Google Patents

Abstract

The invention relates to telecommunications. The goal is to increase the reliability of the device by ensuring its operability in the absence of local power supply. The device contains a broadcast signal source 1, control signal sensors 2 and 9, threshold elements 3 and 17 with an S-shaped volt-ampere characteristic, executive unit 4, controlled generator 5, ring switch 6, transformer 7, disconnection unit 8, diodes 10, 11, 12, 18, 19, resistors 13, 14, 15, capacitors 16, 20. When an external voltage appears at the output of the sensor 2, the rectified voltage corresponding to the external voltage in the line at which the threshold is reached tripping threshold element 3 and passing This input voltage and output power. This signal controls the switching on of the controlled oscillator 5, the signals from the output of which are fed to the input of the ring switch 6, which carries out galvanic isolation from the common buses. 1 il.

Description

The invention relates to telecommunications and can be used to protect radio transmission equipment.

The purpose of the invention is to improve the reliability of the device by ensuring its operability in the absence of local power supply.

The drawing shows the structural electrical circuit of the overvoltage protection device of the communication lines.

The device contains a broadcasting signal source 1, a first control signal sensor 2, a first threshold element 3 with an S-shaped volt-ampere characteristic, an executive unit 4, a controlled oscillator 5, a ring switch 6, a transformer 7, a shutdown unit 8, a second control signal sensor 9, first 10, second 11 and third 12 diodes, first 13, second 14 and third 15 resistors, first capacitor 16, second threshold element 17c S-shaped current-voltage characteristic, fourth 18th and fifth fifth 19 diodes the second capacitor 20.

The device works as follows. . If at time Ti the broadcast signal on common buses has a negative polarity at point A and positive at point B, then the current from point B to point A will flow through the circuit: source 1 of the broadcast signal, point B, resistor 14, diode 10, point A, source 1 broadcast signal.

If at the time moment the polarity of the broadcast signal changes (at point A, the polarity is positive and at point B is negative), the current from point A to point B will flow through the circuit: source 1 of the broadcast signal, point A, resistor 13, diode 11, point B, source 1 broadcast signal.

Thus, in the absence of extraneous voltage, the voltage on the plates of the capacitor 16 is zero.

When the appearance of extraneous voltage 4 between one of the wires of the communication lines and the ground, the device operates as follows

If, at time Ti, the extraneous voltage at point A is positive polarity and the ground is negative, then the current from the source of extraneous voltage flows through the circuit: source E is external voltage, wire of communication line, ring switch 6, common busbars, point A, resistor 13, diode 12, resistor 15, earth, source E, external voltage. The current flowing through the load resistor 15 creates a voltage drop across it, to the level of which the capacitor 16 is charged.

When the polarity of the external voltage is changed, the capacitor 16 is discharged through the load resistor 15. Thus, at the output of the first sensor 2, a rectified voltage appears corresponding to the appearance of the external voltage on the communication lines.

When this voltage reaches the threshold of the first threshold element 3, the latter breaks through and transmits the specified input voltage and power to the output with almost no loss. This voltage is the power supply voltage of the units 4.6 and 8 of the device.

five

The output signal of the first threshold element 3 controls the switching on of the controlled generator 5 through the executive unit 4. The signals from the output of the controlled generator 5 are fed to the input of the ring switch 6. When the input signal arrives, the ring switch 6 turns off each line of communication from the common lines and connects it to common tires

5 through transformer 7, i.e. conducts galvanic isolation from common tires.

When connecting a communication line, on which there is no extraneous voltage, there is also no signal at the output of the second sensor 9

0 and broadcast on this line continues.

When a Damaged line is connected, a signal appears at the output of sensor 9, which, acting on the executive unit 4, turns off the controlled generator 5.

five

When the output signal of the sensor 9 of the control signal is detected, the second threshold element 17 operates similarly to the first threshold element 3, provided by.

0 VA power supply units of the device. In this case, the diodes 18 and 19 and the capacitor 20 provide a guaranteed voltage for the power supply units of the device at all stages of its operation when a foreign voltage is applied to the communication line. When power is applied, unit 8 disconnects the damaged line from the source 1 of the broadcast signal.

The threshold elements 3 and 17 due to the 5-about 0 of different volt-ampere characteristics 1 dwell high input resistance, which reduces leakage of currents of broadcast signals to the ground. If measures are not taken to reduce this harmful leakage, then if one of the wires of the common busbars of the transformer substation is fixed (that is quite possible in real conditions), the source of useful signals will be additionally loaded even in the absence of an external voltage on the communication line. .

Claims (1)

Invention Formula An overvoltage protection device that contains a transformer, the primary winding of which is connected to the first and second outputs of the source of the rotary signal, the first and second inputs of the first sensor control signal and the first and second inputs of the ring switch, and the secondary winding of the transformer is connected to the first and the second inputs of the shutdown unit, the first and second outputs of which are connected respectively to the first and second inputs of the second control signal sensor and the third and fourth inputs About the switch, the output of the second sensor of the control signal is connected to the control input of the actuating unit, the output of which is connected to the input of the controlled generator, the output of which is connected to the control input of the ring switch, each sensor of the control signal consists of the first and second counter diodes whose cathodes are connected to the first terminals of the first and second resistors, respectively, and are respectively the first and second inputs of the control signal sensor, and the second terminals of the first second resistors are combined and connected to anodes first and second diodes, and also with an anode the third diode whose cathode is control sensor output and connected to the first plate of the first capacitor and the first terminal of the third resistor, the other terminal of which, as well as the second plate of the first capacitor, is connected to the common wire, characterized in that, in order to increase the reliability of the device by ensuring its operability in the absence of local power supply, the first and second threshold elements with S-shaped volt-ampere characteristic, the fourth and fifth diodes and the second capacitor, with the output of the first sensor control signal connected to the input of the first threshold element, the output of which is connected to the signal input of the executive unit and the anode of the fourth diode whose cathode is connected to the cathode p the same diode and with the power inputs of the controlled oscillator, ring switch and disconnecting unit, and with the first plate of the second the capacitor, the second plate of which is connected to the common wire, the anode of the fifth diode is connected to the output of the second threshold element, the input of which is connected to the output of the second sensor of the control signal.