SU1239657A1 - Device for determining distance to location of fault in electric power line or communication line - Google Patents

Abstract

The invention relates to electrical measuring technology. The purpose of the invention is to improve the accuracy of determining the distance to the damage. The device contains 1 clock pulse generator, control unit 2, linearly varying voltage generator 3, switch 4, probe pulse generator 5, comparator 6, measuring pulse generator 7, pulse modulator 8, expander amplifier 9. Introduction to the device analog-digital converter 10, digital-to-analog converter 17, register P of signal and interference mix, register 12 interferences, multiplexer 13, subtractor 14, decoder 15, indicator board 16, elements 18 and 19 of coincidence, and the formation of new connections forward device elements allows to dispose of the full-error determining distance resulting mixture nonidentity channels passing signal - noise ratio in one cycle of the device and interference in another cycle, i.e. tune away from asynchronous interference. 2 Il. § cl tc ro co od od

Description

one

The invention relates to electrical engineering.

The purpose of the invention is to improve the accuracy of determining the distance to the damage site due to detuning from asynchronous interference.

FIG. 1 shows a block diagram of the device; in fig. 2 - time diagrams of his work.

The device contains a generator of 1 pulses, the output of which is connected to the input of control unit 2, a generator 3 of linearly varying voltage, the input of which is connected to the second control unit 2 of the control, and its first output to the first input of switch 4. The output of the latter is connected to input Generator 5 probe pulses, the output of which is connected to a controlled

lines; The second output of the generator 3 with a linearly varying voltage is connected to the first input of the comparator 6, the output of which is connected to the input of the generator 7 of measuring pulses. The first output of the generator 3 linearly varying voltage is connected to the second input of the switch 4. The generator code 7 of the measuring pulses is connected to the second input of the pulse modulator 8, the output of which is connected through the expander 9 to the first input of the analog-digital converter 10, and the first input pulse modulator 8 is connected to the controlled line. The information input of the register I 1 of the signal and interference mix is connected to the first output of the analog-digital converter 10 and the information input of the disturbance register 12, the output of which is connected to the second inputs of the multiplexer 13 and the reader 14. The first inputs of the latter are connected to the output of the register 11 of the signal mix and noise and the output of the reader 14 is connected to the first input of the decoder 15, the output of which is connected to the indicator. on the display panel 16. The output of the multiplexer 13 through a digital-to-analog converter 17 is connected to the output of the measuring pulse generator 7 and the second input of the pulse modulator 8. The second input of the decoder 15 is connected to the second output of the analog-to-digital converter 10 and to the first inputs of the first element 1 B coincidence and the second element 19 jointly 396572

fall. The second —Input / i of the first match element 18, is connected to the third output of control unit 2 and the third input of multiplexer 13, and the first

5 output - to the gate input of the register 1 1 smya: and si1: nal and disturbances. The output of the second match element 19 is connected to the gate input of the disturbance register 12.

5 The device operates as follows.

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The output rectangular pulses (Fig. 2 Ct) of the generator 1 are fed to the input of the control unit 2. This unit 2 forms on the first and third outputs of the meanders with a frequency that is half the clock, phase-shifted; relatively, each other at IBo (Fig. 2 S, b), and unipolar rectangular pulses at the second output. The latter start a generator of linearly varying voltage, producing short outputs at the first output.

, negative pulses, I go through the switch 4 to start the generator 5 probe 1 1 pulses. At the second input of the comparator 6, the operator making the measurements sets this or that voltage level with a potentiometer. Since at the output of the comparator 6 a pulse is formed at the moment of equality of the voltage at its inputs, the time interval between the sending of the probe pulse and the output

5 by the pulse of the comparator 6 about the portion of the voltage at the second input voltage. This time interval is directly proportional to the distance to the point of the line viewed by the operator. Therefore, the potentiometer is calibrated in units of length.

The output pulses of the comparator 6 start the generator 7 of measuring pulses, the output pulses of which are fed to the second input of the pulse modulator 8..

The voltage from the monitored line, which contains every odd clock cycle from the probe and reflected pulses, together with the noise (switch 4 is closed) and every even clock only from noise (switch 4 is open), is fed to the first input of the pulse modulator 8, from the output of which im0

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the pulses enter the expander 9, where they expand along the core. Extended pulses arrive at the first input of an analog-specific converter 10, triggered by pulses

(Fig. 2 With () generator 1.

Analog-to-digital converter 10 converts the analog voltage from the first input to an N-bit binary digital code outputted to the first output. Upon completion, a conversion cycle at the second output of the analog-to-digital converter 10, a short rectangular pulse (Fig. 29) is generated, arriving at. The first inputs of the elements 18 and 19 coincidence, the second inputs of which receive square pulses (Fig. 2b, b), respectively, from the first and third outputs of the control unit 2, which are shifted by 180, i.e. appear through

 the operation cycle of the generator 1. Therefore, after the end of the conversion cycle, a pulse appears at the output of that coincidence element, at the input of which at this moment there is a pulse (Fig. 2 e., G) from control unit 2. Pulses from the outputs of elements 18 and 19 of the fall are received

: respectively, to the gate inputs of registers 11 and 12, gating the entry of the binary code from the first output of the analog-digital converter 10 to the information inputs of these registers. The digital codes recorded in registers 11 and 12 are stored until the next strobe pulse from the elements 18 and 19 of the match.

Thus, at each odd clock in register 11, a binary voltage code is written from a line consisting of probing, reflected pulses and interference, and each even clock frequency in register 12 is a binary code corresponding only to the interference voltage. The output codes of the registers 11 and 12 are subtracted in the subtractor 14 and the differential digital code that does not contain interference enters the first input of the decoder 15. The latter converts the binary code into the codes of seven-segment indicators received on the indicator board 16 consisting of lines of seven-segment indicators, on which the coefficient of reflection from the point of the line under investigation, which the operator has selected by the engine of the potentiometer at the second input of the comparator, is displayed

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torus 6. To prevent flicker of numbers on the scoreboard due to the change of codes — in registers 11 and 12, occurring in different measures, the blanking of the indicators was introduced at the time of the change of these codes. The damping is carried out by applying pulses END TRANSFORMATION from the second output of the analog-python converter 19 to the second input of the 10 encoder 15.

The frequency of the quenching pulses is equal to the clock frequency (5-10 Hz), therefore the luminescence of the scoreboard is perceived as constant.

15 To ensure stable and accurate operation, devices in a wide range of input signals have been entered into negative feedback, consisting of a multiplexer 13 and 20 digital-to-analog converter 17. Using multiplexer 13, a digital code is alternately inputted to a digital-to-analog converter 17 from one from registers (11 and 12). Digital-to-25 analog converter 17 converts a digital code into an analog signal, which is a feedback signal. This signal is fed to the second input of the modulator 8. The control of the multiplexer 13 is produced with a signal from the third output of the control unit 2.

Thus, on an odd clock, when the signal – signal and interference mixture comes to the first input of the modulator 8, a feedback voltage is applied to the second input of the modulator, corresponding to the amplitude of this mixture. Even when the first input is affected only by noise, a voltage corresponding to the amplitude of the noise is applied to the second input through the feedback circuit.

When the operator rotates the handle of the rto-tentiometer at the second input of the comparator 6, the indication of the indicator board 16 changes in accordance with the impulse voltage on the cable. The scale of the potentiometer, calibrated in units of length, shows

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distance to viewable point.

The proposed device makes it possible to completely eliminate the errors in determining the distance due to the nonidentity of the transmission channels, the mixture of the signal and interference in one cycle of its operation and the interference in another cycle.

Claims (1)

Formula inveni.ni A device for determining the distance to the damage of power lines and communication, containing generators of clock, probe, measuring pulses and linearly varying voltage, switch comparator, control unit, pulse modulator and amplifier-expander, clock pulse generator output connected to the input of the control unit, the first output of which is connected to the first input of the switch, and the second output to the input of the generator of a linearly varying voltage, the first output of which is connected to the second input of the mutator, and the second output - to the first input switch, output switch podklyuchenk entry of the sounding pulse. the output of which is connected to the terminals for connecting the test object and the first input of the pulse modulator; the second input of the comparator is connected to a potentiometer with a scale calibrated in units of distance; the output of the comparator is connected to the input of the measuring pulse generator, the output connected to the second input of the pulse modulator, the output of which is connected to the input of the amplifier - expander, characterized in that, in order to improve the accuracy of determining the distance to the place of damage, it is provided with an analog digital and digital-to-analogue converters, a signal and interference mix register and a disturbance register, a multi- plexer, a viitel and a decoder of binary codes, indicator board And two elements of a match, the first input of the analog-digital converter is connected to the output of the amplifier-expander, the second input - to the output of the clock generator, the first output - to the information inputs of the interference and signal mixes and interference registers, and the second to the first inputs of the coincidence elements and the second The decoder input, the output of the signal and interference register are connected to the first inputs of the multiplexer and the subtractor, the second inputs of which are connected to the output of the interference register, the gate input of which is connected to the output of the second coincidence element, the second input D which is connected to the first output of the control unit, the third output of the control unit is connected to the third input of the multiplexer and the second input of the first match element, the output of which is connected to the strobe input of the signal and interference mix register, the output of multiplexer 1 is connected to the input of the digital-analog converter, the output of which is connected to the second input of the pulse modulator, the output of the subtractor is connected to the first input of the decoder and the output of the device, the output of the decoder is connected to the indicator board.