RU84129U1 - DEVICE FOR DIAGNOSING THE GROUNDING DEVICE - Google Patents

Abstract

A device for diagnosing a grounding device, comprising a master oscillator, a recorder, an indicator, a current electrode, potential electrodes and a voltage meter inserted into the recorder, a magnetic field strength sensor, characterized in that an electric field strength sensor is added.

Description

The utility model relates to the field of electrical measurements and can be used to assess the state of the grounding devices of electrical installations.

A known device for determining the quality of the grounding device, based on the measurement of the electrical characteristics of the ground loop, in particular, resistance to spreading from grounding devices by the method of ammeter-voltmeter [1]. The device contains an alternating current generator, ammeter, current and potential remote electrodes. Current and potential electrodes are located at a certain distance from the grounding device. In this case, the potential electrode is located at the point of zero potential. One of the poles of the generator and one of the terminals of the voltmeter are connected to the grounding conductor of electrical equipment. The second output of the generator is connected to the current electrode, and the second output of the voltmeter to the potential electrode.

During the measurement, the current from the alternator passes through the circuit formed by the ground loop, an auxiliary current electrode, an ammeter and connecting wires. In this case, part of the current passes directly through the grounding device, and part branches into a potential circuit and passes through a voltmeter to the potential electrode. In the earth, these components of currents are summed up and through the current

the electrode returns to the current source. The measured current in the circuit "grounding device - current electrode" and the voltage of the circuit "ground electrode - potential electrode" calculates the resistance to dissection of current from the ground electrode. Based on the calculated value of the spreading resistance, a conclusion is made about the serviceability of the ground loop. For electrical installations above 1000 V with high earth fault currents, the spreading resistance from the ground loop is regulated by a value of 0.5 Ohm [2]. If the calculated value of this resistance is less, then the ground loop is working. With a larger value of the regulated value of the spreading resistance, measures are taken to reduce the value of this resistance.

A disadvantage of the known device is that with its help you can only indirectly assess the technical condition of the grounding device, the general condition of its elements as a whole.

The closest in technical essence is a device for diagnosing underground conductive objects, containing a master oscillator, a recorder, a sensor in the form of an induction transducer and a current electrode, potential electrodes and a voltage meter, while the voltage meter is inserted into the recorder [3].

When an alternating current is passed through the ground loop from the master oscillator, an alternating magnetic field created by this current is generated around the elements of the ground loop (horizontal stripes and grounding slopes). The registrar determines the magnitude of the intensity of this alternating magnetic field above the earth’s surface along the construction path when the electromotive force (EMF) is induced in it. The change in the induced EMF value is proportional to the change in the magnetic field. When moving the sensor parallel to the surface of the earth by changing the magnetic field, a conclusion is drawn about the path of the elements of the grounding device and its connections with electrical equipment.

The device allows you to determine the location of the elements of the ground loop (horizontal stripes and grounding slopes) and the area of possible damage to grounding slopes.

A disadvantage of the known device is that in the presence of a significant external electromagnetic field (for example, under the conditions of the AC traction substation), the accuracy of determining the location of the elements of the grounding device decreases, and in some cases, the location of the elements of the grounding device becomes impossible.

To eliminate this drawback, a known device containing a master oscillator, a recorder, an indicator, a current electrode, potential electrodes and a voltage meter introduced into the recorder, a magnetic field strength sensor, an electric field strength sensor is added.

When electric current passes from the element of the grounding device to the earth, an electric potential arises on the surface of the earth, the value of which is maximally directly above the element of the grounding device. With a significant increment of the potential per unit length, a more informative parameter is the electric field strength E = gradφ.

Since the influence of an external electromagnetic field on the potential of the earth’s surface is much smaller than on the magnetic field above the earth’s surface, the possibility of increasing the accuracy of determining the location of the elements of the grounding device in the case of a significant external electromagnetic field (for example, under the conditions of an AC traction substation).

In FIG. shows a diagram of the proposed device.

The device comprises a master alternating current generator 1, a remote current electrode 2, a recorder 3, a tension sensor

magnetic field 4, electric field strength sensor 5, indicator 6, voltage meter 7, potential electrode 8.

When connecting the driving alternator 1 with one output to the grounding device 9, and the other to the remote current electrode 2, the current from the generator passes through the circuit formed by the element of the grounding device 9 and the remote current electrode 2. An alternating magnetic field is formed around the elements of the grounding device. created by this current. The magnetic field strength sensor 4 determines the value of the intensity of an alternating magnetic field above the earth’s surface along the construction route, its value is displayed on indicator 6. When moving the sensor parallel to the earth’s surface, a change is made in the magnetic field strength and the connection between the elements of the grounding device and its electrical equipment. By currents flowing from the elements of the grounding device, a potential is created on the earth's surface, the value of which is maximum over the elements of the grounding device. A significant increase in potential leads to a jump in the electric field strength. The magnitude of the electric field of the earth's surface is determined by the sensor 5, its value is displayed on the indicator 6. A voltage meter 7 and a potential electrode 8, as well as a generator 1 and a current electrode 2 make it possible to determine the spreading resistance of the grounding device by the method of an ammeter-voltmeter.

Thus, the proposed device allows you to save the opportunity and improve the accuracy of determining the location of the elements of the grounding device in the case of a significant external electromagnetic field (for example, under the conditions of the traction substation of alternating current).

Information sources:

1. Kostruba S.I. Measurement of electrical parameters of earth and grounding

devices / S.I. Kostruba. - M .: Energoatomizdat, 1983. - 137 p.

2. Rules for the installation of electrical installations: PUE-7: as of May 1, 2005, 2005. Novosibirsk: Siberian University Publishing House. 511 p.

3. Pat. 50316 RF, IPC ⁷ G01R 31/00, H01R 4/66. Device for diagnosing underground conductive objects / Borisov R.K., Koliushko G.M.

Claims (1)

A device for diagnosing a grounding device, comprising a master oscillator, a recorder, an indicator, a current electrode, potential electrodes and a voltage meter inserted into the recorder, a magnetic field strength sensor, characterized in that an electric field strength sensor is added.