RU2334991C1 - Soil resistivity meter - Google Patents

Abstract

FIELD: electrical engineering.

SUBSTANCE: invention relates to power production, particularly to construction of aerial power lines and allows measuring soil resistivity directly in excavation for towers. The soil resistivity meter incorporates current measuring electrodes connected to output contacts by appropriate conductors and a prop for electrodes. It is also furnished with a platform to be installed over the excavation for bearing purposes. The prop is lowered into the excavation along its central axis and attached to the platform bottom. The meter is furnished with horizontal dielectrical electrode guides, stops and a bearing plate. The electrodes and stops are arranged in the said guides to move horizontally and are provided with buffer springs. Both are pivoted to the levers attached to the movable hollow beam arranged in the said prop. The stops are attached to the vertical veering plate. The conductors connected to the electrodes are passed through the aforesaid hollow beam and, further on, connected to the meter terminals.

EFFECT: lower costs and higher measurement accuracy.

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Description

The invention relates to the electric power industry, and in particular to the construction of overhead power lines.

A device for measuring the resistivity of the soil by.with. SU No. 1312495, class G01R 27/20, published May 23, 1987, Bull. No. 19, containing vertical pin probes-electrodes placed coaxially relative to the central probe-electrode, containing in the middle part a measuring conductive zone and two security zones located symmetrically in height relative to this zone.

The disadvantage of this device is that for measurement it is necessary to immerse many auxiliary side probes-electrodes in the ground, the installation of which requires a lot of labor and increases the consumption of metal.

A device for measuring the electrical resistivity of the earth according to patent RU No. 2284531, class. G01R 27/08, published September 27, 2006, Bull. No. 27 (taken as a prototype). The device contains current measuring electrodes connected by independent conductors to the output contacts, and a rack for fixing the electrode.

The disadvantage of this device is the need to immerse it in the ground when preparing a sample of the earth for measurements, which causes significant difficulties when measuring at depths commensurate with the depth of the pits for installing the supports of power lines.

The technical solution to the problem is to reduce the material and financial costs of measurements, increase the accuracy of measurements of resistivity of the earth.

To solve the problem, a device for measuring the electrical resistivity of the earth, containing current measuring electrodes connected by conductors to the output contacts, and a rack for electrodes, is equipped with a platform mounted above the foundation pit for support, on which a rack lowered into the foundation pit is rigidly mounted its central axis, and has horizontal dielectric guides for the electrodes, stops and stop bar, and the electrodes and stops are placed in the guides with the possibility of per the rooms in the horizontal plane are equipped with buffer springs and pivotally connected to levers mounted on a movable hollow rod placed in the rack, and electric wires connected through the hollow rod to the clamps of the measuring devices are attached to the electrodes, and the stops are attached to the vertical stop bar.

The novelty of the device lies in the fact that it is installed on a foundation pit drilled in the ground for support, equipped with a rack lowered into the pit with guides for electrodes and allows them to be immersed in the pit walls. In this case, the measurement of the resistivity of the earth is made in its vertical section, or in layers, before installing the support in the pit. The device allows you to abandon the traditional methods of measurement on the surface of the earth, or from drilling the earth to obtain a sample, makes it possible to measure resistivity taking into account all local features and the topography of the earth, quickly take it into account when installing the grounding device of the support.

The drawing, in a state lowered into the pit, shows a device for measuring the electrical resistivity of the earth in pits for power transmission towers.

The device comprises a support platform 1 mounted above the pit 2, on which a rack 3 with guides 4 made of dielectric material is rigidly fixed from the side of the pit and has adjustment boxes 5. In the rack 3 there is a hollow movable rod 6 with handles 7 On the rails 4 there are installed measuring electrodes 8 and stops 9 connected to the stop bar 10. The electrodes 8 and stops 9 are connected to the rod 6 by means of hinges 11 and pushers (levers) 12 and are equipped with buffer springs 13. The electrodes 8 are attached dineny flexible electrical measuring conductor 14, output through the hollow rod 6 and the surface provided with terminals 15 for connection to a measuring instrument (not shown).

A device for measuring the resistivity of the earth works as follows.

At a picket indicating the exact location of the support on the ground, pit 2 is drilled to the depth specified in the project. The device is prepared for measurements, the length of the rack 3 using the adjustment boxes 5 is set to the depth of the pit. The rod 6 with the help of the arms 7 is lifted upward, while through the hinge joint 11 and the pushers (levers) 12, the measuring electrodes 8 and the stops 9 located on the guides 4 are set to the initial position for operation.

Immediately after drilling and cleaning the foundation pit 2 from the crumbling earth, the platform 1 with the stand 3 is installed over the foundation pit and the rod 6 is lowered using the arms 7. Through swivel joints 11 and pushers (levers) 12, the force is transmitted to the buffer springs 13, and through them to the movable measuring electrodes 8 and stops 9, which are movable on dielectric guides 4, while the electrodes 8 are immersed in the ground on the walls of the pit 2, and the stops 9 press the stop plate 10 against the diametrically opposite wall of the pit 2. Due to the different density of the layers of the earth in the pit, the electrodes 8 can immerse into the ground at different depths, and the stop plate 10 can be pressed with distortions, in such cases Uneven forces perceive buffer springs 13, compensating for uneven movement. The measuring wires 14 are connected to the electrodes 8, they are led outside the pit 2 and are connected to the measuring instruments using clamps 15.

Based on the measurement results, the actual resistivity and the coefficient of seasonal changes in the earth for each individual support are determined.

The positive effect of the proposed device is as follows:

- reduced labor and material costs for measuring the resistivity of the earth;

- improves the accuracy of measurements of resistivity of the earth;

- created the conditions and the possibility of choosing the design and dimensions of the grounding device of the support directly in the field at the place of work;

- reduced cases of overuse of labor and materials on the installation of grounding devices, as well as cases of exceeding the resistance of grounding devices to the requirements of state standards.

Claims (1)

A device for measuring the electrical resistivity of the earth, containing current measuring electrodes connected by conductors to the output contacts and a rack for electrodes, characterized in that it is equipped with a platform mounted above the foundation pit for support, on which a rack lowered into the foundation pit is rigidly mounted its central axis, and has horizontal dielectric guides for electrodes, stops and a stop bar, and the electrodes and stops are placed in guides, with the possibility of moving I in a horizontal plane, and fitted with buffer springs are hinged to levers fixed on the movable hollow rod placed in the rack, wherein the electrodes are attached to electrical cables extending through the hollow rod to the terminals of the measuring devices, and the stops are attached to the vertical abutment plate.