RU2368870C1 - Method for detection of length and corrosion condition of grounding device vertical components - Google Patents

Abstract

FIELD: instrument making.

SUBSTANCE: invention is related to inspection technology and may be used to detect length and corrosion condition of grounding device vertical elements in power supply objects and traction substations of railway transport. Detector is shifted along track of grounding circuit horizontal elements, magnetic field of interference is measured on territory of electric installation, lowest value of interference magnetic field vertical component is fixed on track. Soil is opened down to end part of vertical element. Ultrasonic converter of low-frequency ultrasonic flaw detector is installed on previously cleaned end surface of vertical element. Length of vertical element is identified by flaw detector scan according to ratio: L=C*t/2, where t is time of ultrasound pulse passage through vertical element in both directions, C is speed of ultrasound in medium of vertical element. Corrosion condition is assessed by availability and value of additional peaks in scan. Value of corrosion defect is qualitatively detected by amplitude of echo-signal, defect coordinates are detected by the following ratio: r=C*td/2, where td is time of ultrasound pulse passage to defect area in both directions.

EFFECT: reduced labour intensiveness and time expenditures.

1 dwg

Description

The invention relates to instrumentation and can be used to determine the length and corrosion state of the vertical elements of the grounding device of power supply facilities and traction substations of railway transport.

A known visual method for monitoring the grounding devices of electrical installations. For this, soil digging and instrumental assessment of the condition of grounding conductors and assessment of the degree of corrosion of contact joints are carried out [1, 2].

A known method for determining the corrosion state of the elements of the grounding device located in the ground, according to which local corrosion damage to the grounding conductors are detected during inspection (mainly with the opening of the soil). A quantitative assessment of the degree of corrosion wear is made selectively for areas of the controlled element of the grounding device by measuring the characteristic dimensions, depending on the type of corrosion [3].

The disadvantages of the known methods are the high complexity and significant time costs, given that the vertical elements of the grounding device are usually at a depth of from 0.7 to 1.5 m, and their average length is from 3 to 5 m or more.

Closest to the proposed one is a method for determining the presence of vertical elements of the ground loop, including moving the sensor along the path of horizontal ground loop elements, measuring the magnetic field of the interference in the electrical installation area, fixing the smallest vertical component of the magnetic field of the noise corresponding to the real location on the track of horizontal ground loop elements vertical element of the ground loop [4].

The disadvantage of this method is the inability to determine the length and corrosion state of the vertical elements.

The purpose of the invention is to reduce the complexity and time spent in determining the length and corrosion state of the vertical elements of the grounding device by reducing the amount of earthwork.

To achieve this goal, in the proposed method for determining the length and corrosion state of the vertical element of the grounding device, including moving the sensor along the path of the horizontal elements of the ground loop, measuring on the territory of the electrical installation of the magnetic field of interference, fixing on the track of the horizontal elements of the ground loop the smallest value of the vertical component of the interference magnetic field, excavation to the end of the vertical element, installation on a pre-cleaned end surface of the vertical element of ultrasonic transducer direct the low-frequency ultrasonic flaw detector operating on the principle of pulse-echo method, the determination of the flaw detector sweep (so-called A-scans) the time between excitation pulse and a bottom pulse, the vertical length of the element is determined by the ratio

L = C · t / 2,

where t is the transit time of the ultrasound pulse through the vertical element in both directions (the time interval between the peak of the probe pulse and the peak of the bottom signal reflected from the bottom of the test object, determined by the scan of the flaw detector);

With - the speed of propagation of ultrasound in the environment of a vertical element depends on the properties of the material.

The corrosion state of the vertical element is estimated by the presence and size of additional peaks in the scan of the ultrasonic signal reflected from the opposite end of the vertical element during its longitudinal sounding. Moreover, the value of corrosion damage (defect) is qualitatively determined by the amplitude of the echo signal characterizing the reflectivity of the defect and proportional to its equivalent area, the coordinates of the defect (distance from the upper end of the vertical element) are determined by the ratio:

r = C td / 2,

where td is the transit time of the ultrasound pulse to the defect in both directions (determined by the scan of the flaw detector the time interval between the peak of the probe pulse and the peak corresponding to the echo signal from the defect);

With - the speed of propagation of ultrasound in the environment of a vertical element depends on the properties of the material.

The drawing shows a functional diagram of a device that implements measurements of length and corrosion state by this method.

The device operates as follows.

The synchronizer 1 generates short electrical pulses at certain intervals. These pulses trigger the probe pulse generator 2 and the sweep generator 3. The probe pulse generator generates either radio or video pulses, which are transmitted to the transducer 4 and converted into elastic vibrations in it. These oscillations, propagating in the vertical element of the grounding device 5, form waves. Waves are reflected from obstacles in their path, such as local corrosion damage 6 and the bottom surface. The reflected pulses are returned to the converter and converted into electrical signals. The received signals after amplification and detection in the receiving-amplifying unit 7 are fed to the Y-deflecting plates of the cathode ray tube 8 or other indicator. Sweep generator 3 generates a voltage that depends on time according to a sawtooth law. This voltage is applied to the X-deflection plates of the cathode ray tube. On the screen of the cathode ray tube 8, a scan line (a horizontal line at the bottom of the screen) and one or more peaks are visible. The high peak in the left, initial part of the screen "Z" corresponds to the probe pulse. Peak “D” corresponds to the bottom signal reflected from the bottom of the control object. The “DEF” peak corresponds to an echo from a defect (for example, corrosion damage). The amplitude of the echo signal A characterizes the reflectivity of the defect, it is proportional to its equivalent area, the magnitude of the amplitude A can qualitatively determine the value of corrosion damage. The arrival time of the echo signal t2 allows you to calculate the length of the vertical element, t1 - the coordinates of the defect. The length of the vertical element is determined by the ratio

L = C · t2 / 2,

where t2 is the transit time of the ultrasound pulse through the vertical element in both directions (the time interval between the peak of the probe pulse "Z" and the peak "D" of the bottom signal reflected from the bottom of the test object, determined by the scan of the flaw detector);

With - the speed of propagation of ultrasound in the environment of a vertical element depends on the properties of the material.

The corrosion state of the vertical element is estimated by the presence and size of additional peaks in the scan of the ultrasonic signal reflected from the opposite end of the vertical element during its longitudinal sounding. Moreover, the value of corrosion damage (defect) is qualitatively determined by the amplitude of the echo signal A, which characterizes the reflectivity of the defect and is proportional to its equivalent area, the coordinates of the defect (distance from the upper end of the vertical element) are determined by the ratio

k = C · t1 / 2,

where t1 is the transit time of the ultrasound pulse to the defect in both directions (determined by the scan of the flaw detector the time interval between the peak of the probe pulse "Z" and the peak "DEF" corresponding to the echo signal from the defect);

With - the speed of propagation of ultrasound in the environment of a vertical element depends on the properties of the material.

In this method, the length and the corrosion state of the vertical elements of the grounding device are determined using an ultrasonic flaw detector, which reduces the amount of earthwork. Therefore, the complexity and time spent in determining the length and corrosion state of the vertical elements of the grounding device are reduced.

Information sources

1. Rules for the technical operation of electrical installations of consumers: approved. 01/13/03. - St. Petersburg: Dean, 2003, 301 p.

2. Instructions for grounding power supply devices on electrified railways CE-191 from 10.06.1993 - M .: Transport, 1993, 68 p.

3. RD-153-34.0-20.525-00. Guidelines for monitoring the state of the grounding devices of electrical installations. - M .: SPO ORGRES, 2000, 64 p.

4. Patent 2223510, Russia, IPC ⁷ G01R 27/20. A method for determining the presence of vertical elements of the ground loop / Kandaev V.A., Sveshnikova N.Yu., Kandaev A.V.

Claims (1)

The method of determining the length and corrosion state of the vertical element of the grounding device, including moving the sensor along the path of the horizontal elements of the ground loop, measuring on the territory of the electrical installation of the magnetic field of interference, fixing on the track of the horizontal elements of the ground loop the smallest value of the vertical component of the magnetic field of interference, characterized in that it is opened soil to the end of the vertical element, installation on a previously cleaned end surface the length of the vertical element of the direct ultrasonic transducer of the low-frequency ultrasonic flaw detector, operating according to the principle of the echo-pulse method, the determination by time of the flaw detector (the so-called A-scan) of the time between the probe pulse and the bottom pulse, the length of the vertical element is determined by the ratio:
L = C · t / 2,
where t is the transit time of the ultrasound pulse through the vertical element in both directions (the time interval between the peak of the probe pulse and the peak of the bottom signal reflected from the bottom of the test object, determined by the scan of the flaw detector);
C is the speed of propagation of ultrasound in the environment of a vertical element, depends on the properties of the material;
the corrosion state of the vertical element is estimated by the presence and magnitude of additional peaks in the scan of the ultrasonic signal reflected from the opposite end of the vertical element during its longitudinal sounding, and the value of the corrosion damage (defect) is qualitatively determined by the amplitude of the echo signal, which characterizes the reflectivity of the defect and is proportional to its equivalent area , the coordinates of the defect (distance from the upper end of the vertical element) is determined by the ratio:
r = C td / 2,
where td is the transit time of the ultrasound pulse to the defect in both directions (determined by the scan of the flaw detector the time interval between the peak of the probe pulse and the peak corresponding to the echo signal from the defect);
With - the speed of propagation of ultrasound in the environment of a vertical element, depends on the properties of the material.