RU2782679C1 - Apparatus for non-contact indication of pipeline current - Google Patents

Abstract

FIELD: petroleum industry.

SUBSTANCE: invention relates to the petroleum and gas industry and can be used, in particular, for controlling the effectiveness of electrochemical protection of an underground pipeline from corrosion without affecting the metal of the pipes. Substance: apparatus comprises a reference electrode and at least one non-contact current indicator secured at the welding point on the pipe with a strap made of electrotechnical steel enveloping the pipe. The electrodes and the non-contact current sensor are linked with a measuring instrument unit configured to connect to the cathodic protection means.

EFFECT: higher accuracy of measurement and expanded range of technical means providing indication of the pipeline current without removing the insulating coating of the pipelines.

2 cl, 2 dwg

Description

The invention relates to the oil and gas industry and can be used, in particular, to control the effectiveness of electrochemical protection against corrosion of an underground pipeline without affecting the metal of the pipes, which makes it possible not to remove the insulating coating at the installation sites and to provide the possibility of automated data transmission to corrosion monitoring systems.

The proposed device is designed to measure the direction and strength of the current in the pipeline, and when used in complex corrosion monitoring systems, the indicator makes it possible to detect zones of stray currents near the protected pipeline, determine the anode zones on the pipeline, analyze the current distribution in the cathodic protection section and determine the pipeline insulation damage zones.

A device for non-contact measurement of the current of cathodic protection [RU2379673, C1, G01N 27/72, 20.01.2010], containing a ferroprobe with the first compensation winding, an analog converter that includes a measuring amplifier, the input of which is connected to the output of the fluxgate, and the output to the first selective amplifier, a phase detector and a low-frequency filter connected in series, the first voltage-to-current converter, the output of which is connected to the first compensation winding, an analog-to-digital converter, the digital output of which is connected to the first input of the controller, and the analog input is connected to the output of the low-frequency filter, the generator excitation, the outputs of which are connected to the fluxgate input and the first input of the phase detector, respectively, the second compensation winding, while the analog converter additionally contains an output device, a device for forming time intervals, an indicator, a keyboard, a second selective amplifier and a voltage converter voltage-to-current converter, a digital-to-analog converter and a controlled switch, the first input of which is connected to the first output of the controller, the second output of which is connected to the input of the output device, the input of the first voltage-to-current converter is connected through the first normally closed and normally open contacts of the controlled switch to the output of the low-pass filter and the output of the digital-to-analog converter, respectively, the input of which is connected to the third output of the controller, the fourth and fifth outputs of which are connected, respectively, to the inputs of the indicator and the keyboard, and the second input of the controller is connected to the output of the device for forming time intervals, the input of which is connected to the output of the low-pass filter and through the third normally open contact of the controlled switch with the input of the second voltage-to-current converter, the output of which is connected to the second compensation winding, the second input of the phase detector is connected through the second normally closed and normally open th contacts of the controlled switch with the outputs of the first and second selective amplifiers, respectively, the input of the last of which is connected to the output of the measuring amplifier.

The disadvantage of this technical solution is the relatively high complexity.

The closest in technical essence to the proposed one is a non-contact leakage current monitoring device [RU2379673, C1, G01N 27/72, 01/20/2010], containing a signal generation unit from two sensors, with a selective filter, rectifiers and amplifiers, a correction unit, a leakage current indicator and a residual current device, moreover, the differential sensors are placed on the power supply conductors of the electrical equipment in a non-contact manner, so that the transformer of the sensor of the variable component of the power current wraps around one of the supply conductors of the power supply, and the transformer of the other differential current sensor wraps around both supply conductors of the power current.

The disadvantage of the closest technical solution is the relatively high complexity due to the need to use transformers, as well as the relatively narrow scope due to the ability to measure only relatively high leakage currents of electrified devices.

The task that will be solved in the proposed device is aimed at creating a non-contact current indicator used without affecting the pipe metal, which allows not to remove the insulating coating at the installation sites and provide the possibility of automated data transmission to corrosion monitoring systems.

The required technical result is to increase the accuracy of measurements with a simultaneous expansion of the arsenal of technical means that provide an indication of the current of the pipeline without removing the insulating coating of the pipelines.

The problem is solved, and the required technical result is achieved by the fact that, according to the invention, an auxiliary electrode connected to the measuring instrument unit, a reference electrode and, at least one non-contact current indicator fixed at the welding point on the pipe with an electrical steel fastening tape covering it.

In addition, the required technical result is achieved by the fact that the device for non-contact indication of the pipeline current contains two non-contact current indicators fixed at the welding point on the pipe with a fixing tape made of electrical steel covering it, at a distance from each other equal to 1 meter.

The drawing shows:

in fig. 1 - device for non-contact indication of pipeline current for the case of using one non-contact current indicator fixed on a pipe with an electrical steel fastening tape covering the pipe;

in fig. 2 - device for non-contact indication of pipeline current for the case of using two non-contact current indicators mounted on a pipe with fixing bands made of electrical steel around the pipe.

The device for non-contact indication of the pipeline current contains a block 1 of measuring instruments, located in the rack of the control and measuring point and made with the possibility of connection with means of cathodic protection and connected to the block of measuring devices, an auxiliary electrode 2 and a reference electrode 3.

In addition, the device for non-contact indication of the pipeline current contains at least one non-contact current indicator 4 fixed on the pipe 5 with a fixing tape 6 made of electrical steel covering the pipe (Fig. 1).

In a particular case, the device for non-contact indication of the pipeline current may contain two non-contact current indicators 4 with electrical steel fastening bands covering the pipe, fixed on the pipe 5 at a distance from each other equal to at least 1.5 m (Fig. 2). In a particular case, this distance is preferably 1 m.

A device for non-contact indication of pipeline current is used as follows.

The presented device is designed to measure the direction and strength of the current in the pipeline.

In addition, with complex use in corrosion monitoring systems, the device allows solving the following tasks:

- detection of stray current zones near the protected pipeline;

- determination of anode zones on the pipeline;

- analysis of current distribution in the area of cathodic protection;

- determination of pipeline insulation damage zones.

The principle of operation of the device is based on the Hall effect and for the most accurate measurement, the use of a non-contact current indicator 4 is provided, which is mounted on top of a pipe with a fastening tape 6 made of electrical steel without damaging the insulation. After power-up, the device performs continuous measurements of the direction and strength of the current and transfers the measured values via the interface communication line RS 485. Data transfer protocol Modbus RTU (Slave).

Thus, due to the use of an auxiliary electrode, a reference electrode and at least one non-contact current indicator fixed at the welding point on a pipe with a fixing tape made of electrical steel covering it, the required technical result is achieved, which consists in increasing the accuracy of measurements with simultaneous expansion an arsenal of technical means that provide indication of the current of the pipeline without removing the insulating coating of pipelines and automated transmission of data to corrosion monitoring systems.

Claims (2)

1. A device for non-contact indication of pipeline current, containing a block of measuring instruments, made with the possibility of connection with means of cathodic protection, characterized in that an auxiliary electrode connected to the block of measuring instruments, a reference electrode and at least one non-contact current indicator fixed in welding point on a pipe with a fixing tape made of electrical steel covering it. 2. The device according to claim 1, characterized in that the device for non-contact indication of the pipeline current contains two non-contact current indicators fixed at the welding point on the pipe with an electrical steel fastening tape covering it, at a distance from each other equal to 1 m.

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