SU1224752A1 - Apparatus for determining range to cable power line damage - Google Patents

Abstract

This invention relates to electrical measuring technology. The purpose of the invention is to increase the noise immunity of the device. The shaper 5 receives impulses of the reference and envelope frequencies from divider 4 of the chaytot and forms a packet of probe pulses of the reference frequency sent to the cable line under study and simultaneously forms a pulse starting at the falling front and entering the measurement unit 2. The locking unit 3, after sending the last of the probe pulse bundle, produces a pulse of the useful signal. When the impulses receive interference, the counter 6, after their passage, is reset to zero and the stop impulse is not formed. The introduction of a frequency divider and probe pulse shaper into the device allows one to fill the interval of the probe pulse with f 30 kHz frequency pulses. This reduces the probability of the occurrence of interference pulses, eliminates the loss of pulses reflected from the site of damage, and increases the stability of the parameters of the pulses reflected from the site of damage. 2 Il. in g 1C th 4: vj ate yu

Description

The invention relates to electrical measuring equipment and can be used in determining the distance to a fault in cable lines of electricity transmission.

The purpose of the invention is to reduce the noise immunity of the device by sending probing pulses of f 30 kHz frequency pulses to the cable line, thereby reducing the likelihood of interference in reflected pulses.

Figure 1 shows the functional diagram of the device; 2 (ak) —time diagrams of the operation of the device units J (a is the generator output, b is the second divider output, c is the first divider output g is the first driver output, the second driver output, e is the clamping device input, f - impulse impulse, 3 - output of the fixing device, and - output of the counter, k - output of the measuring unit).

The device contains a generator of 1 probe pulses, a measurement unit 2, a fixing unit 3, a divider 4 frequencies, a shaper pulse generator 5, a pulse counter 6, a terminal 7 for connection to the test object.

The output of the probe pulse generator 1 is connected to the input of the frequency divider 4 and the counting input of the measurement unit 2. The first output of the splitter 4 frequency is connected to the first input of the driver 5 probe pulses. The second output of the 4 frequency divider is connected to the second input of the shaper pulse generator 5, the first output of which is connected to terminal 7 for connecting to the control object and the input of the fixing unit 3. The second output of the shunting pulse shaper 5 is connected to the first control input of the measurement unit 2. The output of the fixing unit 3 is connected to the input of the counter 6, the output of which is connected to the second control input of the measuring unit 2.

The device works in a manner.

The probe pulses formed by the generator 1 are fed to the input of the 4 frequency divider, from the first output of which Pulses of the reference frequency are removed (Fig. 2c), which is selected from the condition of f 930 kHz, and

from the second output of the divider 4 frequency, pulses of the envelope frequency are removed (Fig. 2b), which makes it possible to obtain h pulses. When done

these conditions, the rectangular pulses have small losses and are practically not distorted by

The impulses of the reference and bending frequencies of it come to the corresponding

inputs of the pulse generator 5, which forms a bundle of sounding pulses of the reference frequency, sent to the cable line under study (Fig. 2e) 5 simultaneously the pulse driver 5 generates a pulse on the falling edge of the first control input of the unit. 2 measurements (fig. 2d), i.e. After sending the last cable from the probe pulse to the cable line being examined, the counting input of the measurement unit 2 starts to receive pulses from the probe pulse generator 1.

For the time of sending the probing pulses into the test leg line, the input of the fixing unit 3 is in the closed state only after the last of the

Bundle of the probe pulse, the input FIR1) of the scanning unit 3 is ready to receive reflected pulses from the damage site (Fig. 2e).

The locking unit 3 produces a selection of pulses useful signal

la, t „e. fixes them

pulses reflected from the place of damage in amplitude. The value of the amplitude of the first incoming pulse is memorized for a time equal to the period of the probe pulses, and the amplitudes of the subsequent incoming pulses are compared with the memorized value; In equal amplitudes with fixing unit

3, a pulse arrives at counter 6, which counts the pulses of the useful signal coming from the fixed output;) of block 3, and on the leading edge of the last reflected pulse from the damage site generates a stop pulse arriving at the second (control input of measurement unit 2).

When a noise is received on the fixing block 3 of the pulses of the counter 6 after their passage, it is reset to zero and the stop pulse is not generated from the output of the counter 6.

Introducing the frequency divider 2 and the probe pulse imaging unit 5 allows filling the interval of the pulse pulse probe with f 30 kHz frequency pulses, reducing the likelihood of interference impulses, eliminating the loss of impulses reflected from the damage site, and increasing the stability of the parameters of the impulses reflected from damage sites, while the fixing unit 3 responds only to the pulses of the useful signal and the counter 6 performs their counting and, on the arrival of the latter, stops the measurement process, t. . In measurement block 2, a time interval proportional to the distance to the damage site is measured.

Thus, the proposed device has a sufficiently high noise immunity and resolution, which improves the accuracy of measuring the distance to the damage in cable lines.

Claims (1)

Invention Formula A device for determining the distance to the fault cable1224752 0 five 0 power lines; comprising a probe pulse generator, a measurement unit, a clamping block, characterized in that, in order to improve noise immunity, a frequency divider, a probe pulse shaper, a pulse number counter are inputted, the probe pulse generator output is connected to the frequency divider input and the counting input of the block measurement, the first output of the frequency divider is connected to the first input of the probe pulse generator, the second output of the frequency divider is connected to the second input of the probe pulse generator, the first psod which is connected to a terminal for connection to a control object and the input of the locking unit, the second output of the sounding pulse is coupled to a first control input of the measuring unit, the locking unit output is connected to the counter input, which is connected to vpsod vtorsh control input of the measuring unit.