SU1638679A1 - Device for measuring distance from failure in feeder cable - Google Patents

Description

one

(21) 4612191/21

(22) 01 J2.88

(46) 30 „03о91. Bul, № 12

(72) N.S.Nikolaev and V.N.Kistenev

(53) 621.317-2889 (088.8)

(56) Reflectometer P5-5. Technical description, 1981, s023o

Arisshenkov I.L., Supakov NIA The High Frequency Path of the Short-Wave Receiving Radio Center. J .: Svyaz, 1975.

(54) DEVICE FOR DETERMINATION OF DISTANCE TO THE TROUBLE OF FAILURES IN FIDER LINES

(57) The invention relates to the field of electrical measurements and can be used to verify the health of feeder lines at the receiving and transmitting

 communication centers, as well as there,

where there are air or cable feeder lines. The purpose of the invention is to improve the accuracy of determining the distance to the fault site. The device contains a probe pulse generator 1 connected in series, a power amplifier 2 and a measuring unit comprising a serially connected electronic switch 3, first delay line 4, pulse shaper 5, pulse counters 6, 9 forming trigger 7 and element 8 as well as a decoder 10, an electronic scoreboard I, Strobe pulses are received from the generator 13 strobe pulses, the start input of which through a delay line I2 is connected to the input of the generator 1 of probing pulses I Zo P. f-ly, 2 il.

at 8

WITH

The invention relates to electrical measurements and can be used to check the health of feeder lines at receiving and transmitting telecommunication centers, as well as where there are overhead or cable feeder lines.

The aim of the invention is to improve the measurement accuracy.

The structural diagram of the device is presented in figure 1; figure 2 - timing diagrams.

The device contains a generator of 1 probe pulses, power amplifier 2, first electronic switch 3, first delay line 4, pulse generator 5, first pulse counter 6, forming trigger 7, element 8, second pulse counter 9, decoder 10, scoreboard P, a second delay line 12, a strobe pulse generator 13, a second 14 and a third 15 electronic keys, the output of each of which is connected via a LED to a common busbar

The output of the probe pulse generator 1, the first control input of which is connected to the Start terminal through the power amplifier 2, is connected to the input for the tested feeder line and to the serially connected & CO 00

ee j

the first electronic key 3, the first delay line 4, the pulse shaper 5, the first pulse counter 6 forming the trigger 7, the AND 8 element, the second pulse counter 9 of the pulse. In addition, the generator 1 output is connected to the control input of the first electronic key pulses are also connected to the second control input of generator 1, and the output of the first counter of 6 pulses is additionally connected to the third control input of generator 1. The second input of the AND 8 sub-keys to the output of the generator 13 strobes them The first control input of which is connected to the first control input of the generator through the second delay line 12 and the second control input to the output of the first counter 6 pulses. The parallel outputs of the second counter 9 pulses are connected to the corresponding inputs of the decoder 10, and the outputs of the decoder 10 are connected to the corresponding inputs of the electronic board 11 “The output of the first electronic key 3 is also connected to the inputs of the second 14 and third 15 electronic keys, to the output of each of which one LED is connected, s contacts are combined and connected to a common shinoyu Installation inputs of the first 6 and second 9 meters and forming trigger pulses 7 are connected to a first control input of oscillator 1.

The device works as follows.

At the first moment of time, a Start command pulse is sent to the first control input of the generator 1 of probe pulses from external circuits, through which a positive probe pulse is generated to the generator (fit 2a). At the same time, the Start command pulse is initialized to the zero state of the first 6 and second 9 pulse counters and the forming trigger 7 is tilted. At the output of the trigger 7, a potential appears, opening element AND 8 at the first input (the beginning of the equivalent measurement interval is formed) .

The probing pulse from the output of the generator 1 is fed through the amplifier 2 of the power to the feeder under test and simultaneously to the control input of the primary

five

about 5 l

five

electronic key 3, closing it for the time of passage of a powerful pulse from the output of amplifier 2 power and thus preventing the driver 4 of the pulses and electronic keys 14 and 15 from failing.

Reflected from the heterogeneity in the place of damage to the feeder pulse through the open first electronic key 3 is fed to the inputs of the first delay line 4 and the second and third electronic keys 14 and 15 (Fig 102).

The sign of the reflected pulse can determine the nature of the fault in the feeder. If the reflected pulse does not change its sign with respect to the probe, then there is an open line in the line, and if the sign is reversed, then the second 14 and third 15 electronic keys short circuit is intended to detect the sign of the reflected pulse. If the reflected pulse is positive, the third electronic key 15 opens and the LED indicating the Open circuit lights up, and if the reflected pulse is negative, the second electronic key 14 opens and the lit LED indicates a Short circuit.

The first 4 delay line is necessary to increase the interval between the probe and reflected pulses by a certain DTg. This delay is introduced in order to increase the resolution of the device at short distances to the place of the feeder failure from its beginning. In such cases, the duration of the interval between the probe and reflected pulses is a few or fractions of a few nanoseconds, and the problem arises

with the measurement of this interval.

I

From the output of the first delay line 4 (Fig. 2b), the reflected and delayed pulses go to the pulse shaper 5, where a positive pulse is generated from a positive or negative pulse, which triggers the probe pulse generator at the second control input and simultaneously records 6 pulses to the first counter. In this case, the first measurement cycle is formed. The probe pulse generator 1 produces a second probe pulse (), and the described process repeats until M is formed.

5 16

after which a pulse appears at the end of the measurement, the first counter of pulses 6, which stops the operation of the probe pulses generator 1 (Fig. 2g). At the same time, with this pulse, the forming trigger 7 is transferred to the state closing the element AND 8 through the first input at the second input (the formation of the equivalent measurement interval

& T - ,,,). In addition, the same impulse 1

som stops generator 1

probe pulses, which was triggered by a pulse (FIG. 2 and) of the Start command via the second delay line 10 at the initial measurement moment.

The delay time of the pulse in the second delay line 10 is selected from the condition of compensation for the delay in the first line of the back of 4 for M measurement cycles, i.e. AT.2 M Dt. At the same time, the equivalent measurement interval A T 9 is added up from D T j / z and - counting interval & TSC, the duration of which must be measured to measure the distance to the fault location, the period of the gating pulses corresponding to the specified measurement accuracy, and their number (figure 2k) to the distance to the meta fault in the feeder. The number of pulses, reflecting the distance to the fault from the pulses parallel to the second counter 9 pulses, is recorded in the Binary Decoder 10 and indicated on the electronic digital display board 11, since the device must work with different types of feeders (air and cable), then, to ensure the same measurement accuracy, the first pulse counter 6 must be performed with a variable counting factor, and the second delay line 12 with a variable delay time

Primer p. The necessary ratios can be calculated for ICs with cut-off frequencies up to 10-15 MHz. Let the required accuracy be 0.1 m. Then, for air feeders, the following frequency (increase in the period) of gating pulses should be reduced by 51 times and for cables - by 34 times (if the frequency of the following gating pulses is 14 MHz).

Q

five

0 5 0 d

five

0

0

5 Delay time DT, for example, select 0.8 μs so that 1 gate pulse is placed on this interval. At the same time, AT-) is 1 40.8 μs, and for the cable 27.2 μs.

Claims (2)

1. A device for determining the distance to the fault in the feeder lines, containing a generator of probe pulses, the first control input of which is connected to the Start terminal, an input for connecting a controlled feeder line, characterized in that, in order to improve the measurement accuracy A power amplifier is inputted, the input of which is connected to the output of the probe pulse generator, and the output is connected to the input for connecting a controlled feeder line, the first electronic switch connected in series, the first delay line ki, pulse generator, first pulse counter, forming trigger, element I, second pulse counter, the control input of the first electronic key connected to the output of the probe generator, the output of the pulse former connected to the second control input of the probe pulse generator connected to the third control input of the generator of probe pulses, the second input of the element I is connected to the output of the generator of gating pulses, the first control input of which go through the second line. The delay is connected to the first control input of the probe pulse generator, the second control input of the gate pulse generator is connected to the output of the first pulse counter, the outputs of the second pulse counter are connected to the corresponding inputs of the decoder, the outputs of which are connected to the output of the first electronic key the inputs of the second and third electronic keys, the outputs of each of which are connected via a LED to the common bus of the device, the installation inputs of the first and second o, counters and pulse forming trigger connected to the first control input of the sounding pulse generator. 2. The device according to claim 1, characterized in that the first pulse counter is made with variable Start Feeder counting factor, and the second delay line is made with a variable delay time.