CN104947118B - Flexible anode breakpoint detection method - Google Patents

Abstract

The invention discloses a flexible anode breakpoint detection method, which is used to detect the breakpoint of the flexible anode of the cathodic protection system. The detection method adopts a detection device, and the device includes: a potentiostat; an anode cable electrically connected to the Described potentiostat and described flexible anode; Copper sulfate reference electrode; Measuring lead wire; Digital multimeter, the black test lead of described digital multimeter is electrically connected with described copper sulfate reference electrode through described measuring lead wire; Test stake, through The test cable in the test pile is electrically connected to the buried metal pipeline; the method includes: opening the potentiostat, so that the potentiostat is periodically turned on/off; the copper sulfate reference electrode is sequentially Placed at different measurement points, the side measurement point is located on the ground surface directly above the buried metal pipeline; read the power-on potential and power-off potential of different side measurement points displayed on the digital multimeter; according to different measurement points The breakpoint position of the flexible anode is obtained between the breakpoint potential distributions.

Description

A flexible anode breakpoint detection method

technical field

The invention relates to the technical field of pipelines for transporting oil and gas, in particular to a flexible anode breakpoint detection method.

Background technique

my country's long-distance oil and gas pipeline stations and urban gas pipeline network-intensive areas all use regional cathodic protection systems to implement cathodic protection for buried metal pipelines to slow down or inhibit the corrosion of the outer wall of buried metal pipelines. The composition of the cathodic protection system is mainly composed of four parts: DC power supply, anode bed, protected pipeline and auxiliary equipment, among which the anode bed is the core part of the system circuit. However, due to the complex structure of the protected object, the limited installation area, and the large current demand of the regional cathodic protection system, the design and construction of the anode bed are limited by the area and safety distance, and are affected by the shielding of the grounding system, and its application effect is quite different. .

The development and update of regional cathodic protection technology can be attributed to the evolution and development of the anode form used. Nearly 30 years of regional cathodic protection experience in China has proved that the form and location of the anode bed are crucial to the successful application of the cathodic protection system in the station area. The emergence of flexible anodes overcomes the problems of interference shielding and uneven distribution of protection current. Meanwhile, the flexible anode is a soft, cable-shaped auxiliary anode with a diameter of only a few centimeters. Lay in the same ditch as the pipeline during construction, with a distance of 20-30cm, not limited by the area. At present, flexible anodes have been widely used in regional cathodic protection systems for buried pipelines in domestic and foreign stations. In the United States, flexible anodes are widely used in the protection of petroleum metal facilities, the protection of underground metal piping and structures in power plants, and the protection of ship docks. In EU regulations, flexible anodes are also recommended for regional cathodic protection. At present, MMO flexible anodes with high drainage density and long life are widely used in the world.

In the field application in recent years, the application effect of the flexible anode is better, but it is prone to open circuit. There is no current on the anode after the breakpoint, and the corresponding protected pipe section cannot be effectively protected. Since the grounding effect of the flexible anode is better, if the breakpoint occurs more than 100 meters away, it is impossible to judge whether there is a breakpoint only by testing the grounding resistance value of the anode. Only the protection potential of the pipeline can reflect whether the anode is broken. For the search of breakpoints, some engineers have used RD-PCM pipeline positioning detection equipment to search, and found that the detection current signal loaded by the transmitter decays rapidly after 50 meters, and the current signal on the anode after that is very weak. has been undetectable.

Contents of the invention

The present application provides a flexible anode breakpoint detection method, which solves the technical problem that the flexible anode breakpoint cannot be located in the prior art.

The application provides a flexible anode breakpoint detection method, which is used to detect the breakpoint of the flexible anode of the cathodic protection system. The detection method uses a detection device, and the device includes: a potentiostat; an anode cable, electrically connected The potentiostat and the flexible anode; copper sulfate reference electrode; measurement lead; digital multimeter, the black test lead of the digital multimeter is electrically connected to the copper sulfate reference electrode through the measurement lead; test pile, The test cable in the test pile is electrically connected to the buried metal pipeline, and the test cable measurement point of the test pile is electrically connected to the red test lead of the digital multimeter; the method includes: opening the potentiostat , so that the realization of the potentiostat is periodically turned on/off; the copper sulfate reference electrode is placed at different measurement points in turn, and the side measurement point is located on the ground surface directly above the buried metal pipeline; read The power-on potential and power-off potential of different measurement points displayed on the digital multimeter; the breakpoint position of the flexible anode is obtained according to the power-off potential distribution between different measurement points.

Preferably, when there are multiple potentiostats and there is no "power-off test" function, the detection device further includes a synchronous current interrupter arranged on the anode cable.

Preferably, the measurement point is located on the surface directly above the buried metal pipeline, and the distance between two adjacent measurement points is 1 meter.

Preferably, the measuring point covers up to the end position of the flexible anode.

Preferably, the obtaining the breakpoint position of the flexible anode according to the power-off potential distribution between different measurement points specifically includes:

Generate a potential data-measuring point curve according to the power-off potential between different measuring points;

Obtain the attenuation starting point of the power-off potential according to the potential data-measurement point curve;

judging whether the power-off potential continues to decay from the starting point to the end of the flexible anode;

If yes, then 1 to 2 meters in front of the side measurement point corresponding to the starting point is the breakpoint position of the flexible anode.

The technical solution of the present application has at least the following beneficial effects:

In the flexible anode breakpoint detection method provided by the present application, the potentiostat is turned on, so that the potentiostat is periodically turned on/off, the copper sulfate reference electrode is placed at different measuring points in sequence, and the reading The power-on potential and power-off potential of different measuring points displayed on the digital multimeter can obtain the breakpoint position of the flexible anode according to the power-off potential distribution between different measurement points, which improves the inability to locate in the prior art Technical issues of flexible anode breakpoints.

Description of drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the accompanying drawings that need to be used in the description of the embodiments. Obviously, the accompanying drawings in the following description are only of the present invention. some examples.

Fig. 1 is a flow chart of a flexible anode breakpoint detection method in a preferred embodiment of the present application;

Fig. 2 is the structural representation of the detection device that the flexible anode breakpoint detection method in Fig. 1 adopts;

Fig. 3 is a potential data-measuring point curve diagram detected by the flexible anode breakpoint detection device in Fig. 1 .

Wherein 1—potentiostat 2—anode cable

3—cathode cable 4—zero connection negative wire

5—Long-term reference electrode wire 6—Long-term reference electrode

7—Flexible anode 8—Buried metal pipe

9—Test pile 10—Digital multimeter

11—Copper sulfate reference electrode 12—Measurement lead

13—Synchronizing Current Interrupter 14—Measuring Point

15—Flexible Anode Terminal

detailed description

The embodiment of the present application solves the technical problem that the flexible anode breakpoint cannot be located in the prior art by providing a flexible anode breakpoint detection method.

The technical solution in the embodiment of the present application is to solve the above-mentioned technical problems, and the general idea is as follows:

In the flexible anode breakpoint detection method provided by the present application, the potentiostat is turned on, so that the potentiostat is periodically turned on/off, the copper sulfate reference electrode is placed at different measuring points in sequence, and the reading The power-on potential and power-off potential of different measuring points displayed on the digital multimeter can obtain the breakpoint position of the flexible anode according to the power-off potential distribution between different measurement points, which improves the inability to locate in the prior art Technical issues of flexible anode breakpoints.

In order to better understand the above-mentioned technical solution, the above-mentioned technical solution will be described in detail below in conjunction with the accompanying drawings and specific implementation methods.

The present application provides a flexible anode breakpoint detection method for detecting the breakpoint of the flexible anode 7 . The detection method uses a detection device. As shown in FIG. 2, the device includes a potentiostat 1, an anode cable 2, a copper sulfate reference electrode 11, a digital multimeter 10, and a test pile 9.

The anode cable 2 is electrically connected to the potentiostat 1 and the flexible anode 7 . The cathode cable 3 is electrically connected to the potentiostat 1 and the buried metal pipeline 8 . The negative connection wire 4 at zero position is electrically connected to the potentiostat 1 and the buried metal pipeline 8 . The long-term reference electrode wire 5 is electrically connected to the potentiostat 1 and the long-term reference electrode 6 . The copper sulfate reference electrode 11 is placed at the measurement point directly above the pipeline, the side measurement point is located on the ground surface directly above the buried metal pipeline, and the measurement point covers to the terminal position of the flexible anode. In this embodiment, the copper sulfate reference electrode 11 can be placed at different measurement points 14 to perform potential measurement on multiple measurement points.

The black test lead of the digital multimeter 10 is electrically connected with the copper sulfate reference electrode 11 . The test pile 9 is electrically connected to the buried metal pipe 8 through the test cable in the test pile, and the test cable measurement point of the test pile 9 is electrically connected to the red test pen of the digital multimeter 10 . Specifically, the test pile 9 is connected to the test cable measurement point and the red test lead of the digital multimeter 10 through the measurement lead 12, and the black test lead of the digital multimeter 10 is connected to the copper sulfate reference electrode 11, along the buried line shown in the cathodic protection design drawing. The parallel routing of the ground metal pipeline 8 and the flexible anode 7 tests the power-on potential and the power-off potential of the buried metal pipeline 8 at a distance of 1 meter, and the distance between two adjacent measurement points is 1 meter, and the copper sulfate reference The electrode 11 tests the potential directly above the pipeline along the layout of the measuring point 14 in FIG. If the flexible anode is not applied to the end of the pipe, the measurement shall continue to the end of the pipe.

During on-site testing, it is required to test the energization potential and the de-energization potential of the buried metal pipeline 8 . When the potentiostat 1 has the function of "power-off test", the "power-off test" mode can be directly turned on; when the potentiostat 1 does not have the function of "power-off test", or there are multiple To realize synchronous on-off, a synchronous current interrupter 13 needs to be installed on the anode cable to realize synchronous on-off of multiple potentiostats 1 .

As shown in Figure 1, the method includes the following steps:

Step S11, turning on the potentiostat, so that the potentiostat is periodically turned on/off;

Step S12, placing the copper sulfate reference electrode at different measurement points in sequence, and the side measurement points are located on the ground surface directly above the buried metal pipeline;

Step S13, reading the power-on potential and power-off potential of different measuring points displayed on the digital multimeter;

Step S14, obtaining the breakpoint position of the flexible anode according to the power-off potential distribution among different measurement points.

After the test is completed, the test data is plotted and analyzed. Specifically, the obtaining the breakpoint position of the flexible anode according to the power-off potential distribution between different measurement points specifically includes:

Generate a potential data-measuring point curve according to the power-off potential between different measuring points;

Obtain the attenuation starting point of the power-off potential according to the potential data-measurement point curve;

judging whether the power-off potential continues to decay from the starting point to the end of the flexible anode;

If yes, then 1 to 2 meters ahead of the side measurement point corresponding to the starting point is the breakpoint position of the flexible anode; if not, then determine the breakpoint position of the non-flexible anode where the starting point is densely distributed in buried metal structures .

As shown in Figure 3, the data of the power-on potential and the power-off potential tested along the pipeline are shown in the figure. The data of the power-off potential is relatively stable, in which the potential attenuation section 1 and the potential attenuation section 2 appear, and the attenuation of 2 meters occurs for the first time Afterwards, the power-off potential returned to the normal level. This section was judged to be caused by the shunt interference of the grounding material around the pipeline. Therefore, during the on-site test, the tester must test to the terminal position of the anode to prevent misjudgment. After the second attenuation in the figure, the potential no longer returns to the normal level, but continues to attenuate. At this time, it can be judged that the range of 1 to 2 meters in front of the starting point of the potential attenuation section 2 is the breakpoint or terminal of the flexible anode . If the drawing shows that this is not the terminal position of the anode, it can be judged as the breakpoint of the flexible anode.

The flexible anode breakpoint detection method provided by this application judges the breakpoint of the flexible anode according to the actual layout of the buried metal pipeline and the flexible anode, and according to the distribution of the pipeline protection potential under the action of cathodic protection, and analyzes the encryption test to obtain the pipeline energization potential and The breakpoint position of the flexible anode can be judged by the attenuation trend of the power-off potential, which solves the technical problem that the breakpoint of the flexible anode cannot be located in the prior art.

When the cathodic protection system is running, the application uses a digital multimeter with high precision and high sampling rate to encrypt (generally at a distance of 1 meter to 2 meters) to test the energization potential of the pipeline by turning on the "power-off test" mode directly above the target pipeline and power-off potential, and then after data processing, the breakpoint of the flexible anode is located. The off-voltage potential of the pipeline tested in this mode is the polarization potential of the pipeline. Due to the close distance between the flexible anode and the pipeline, the polarization potential distribution of the protected pipeline is uniform and the difference is small under normal operating conditions. By detecting the distribution of the polarization potential of the pipeline, it can be judged whether there is a breakpoint in the flexible anode, and then by encrypting the distribution of the polarization potential of the pipeline, the location of the breakpoint of the flexible anode can be located.

During the implementation of the flexible anode breakpoint detection method disclosed in this application, one should first understand the direction of the protected pipeline in the entire station or area, and investigate the anode laying situation in the design drawing of the cathodic protection system. If there are multiple circuits in the system, the anode laying route corresponding to each circuit shall be specified. When the cathodic protection system power supply equipment (generally a potentiostat) is normally turned on, turn on the "power-off test" mode of the equipment, the on-off cycle is adjustable, generally 12s on, 3s off, read within 100ms to 300ms after power off The potential of the pipeline to ground is the power-off potential, which is the polarization potential of the pipeline. If in a multi-circuit system, multiple power devices cannot be interrupted synchronously, it is necessary to install synchronous current interrupters on each circuit separately. When the power supply equipment is switched on and off synchronously, according to the route laid by the flexible anode in the drawing, use a high-precision digital multimeter to test the power-on potential and power-off potential of the pipeline at a distance of 1 meter until the terminal of the flexible anode is tested. The potential data is plotted and analyzed. In the position where the potential attenuation is obvious, and the potential of the subsequent pipe section cannot be restored to the normal protection level, it can be judged that the position at which the potential attenuation is obvious is the breakpoint of the flexible anode, and the positioning accuracy can reach 1 meter. When the potential of the subsequent pipe section returns to the normal protection level, it is generally caused by the influence of dense grounding materials. At this time, the potential position cannot be judged as the breakpoint position of the flexible anode.

The beneficial effect of the present invention is that it can quickly, effectively and accurately determine whether there is an open circuit in the flexible anode of the cathodic protection system, and at the same time, the breakpoint of the flexible anode can be located within the range of 1 to 2 meters after passing the encrypted test, without affecting the system The normal operation of the cathodic protection system provides technical support for the operation, maintenance and troubleshooting of the cathodic protection system.

While preferred embodiments of the invention have been described, additional changes and modifications to these embodiments can be made by those skilled in the art once the basic inventive concept is appreciated. Therefore, it is intended that the appended claims be construed to cover the preferred embodiment as well as all changes and modifications which fall within the scope of the invention.

Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalent technologies, the present invention also intends to include these modifications and variations.

Claims (4)

1. A kind of 1. flexible anode breaking point detection method, for detecting the breakpoint of cathodic protection system flexible anode, it is characterised in that The detection method uses a detection means, and described device includes：

   Potentiostat；

   Anode cable, it is electrically connected with the potentiostat and the flexible anode；

   Copper sulfate reference electrode；

   Measure lead；

   Digital multimeter, the black meter pen of the digital multimeter are electrical by the measurement lead and the copper sulfate reference electrode Connection；

   Test pile, it is electrically connected with by test cable in test pile and buried metal pipeline, and the test cable of the test pile The red test pencil of measurement point and the digital multimeter is electrically connected with；

   Methods described includes：

   Open the potentiostat so that the potentiostat periodicity on/off；

   The copper sulfate reference electrode is sequentially placed into different measurement points, the measurement point position is in the buried metal pipeline The earth's surface of surface；

   Read the energization current potential and switch-off potential of the different measurement points shown in the digital multimeter；

   The breakpoint location of the flexible anode is obtained according to the switch-off potential distribution between different measurement points；

   The switch-off potential distribution according between different measurement points obtains the breakpoint location of the flexible anode, specific bag Include：

   One potential data-measurement point curve is generated according to the switch-off potential between different measurement points；

   The decay starting point of the switch-off potential is obtained according to the potential data-measurement point curve；

   Judge the switch-off potential whether from the starting point continuous decrement to the terminal of the flexible anode；

   If so, then 1 ~ 2 meter of measurement point front corresponding to the starting point is the breakpoint location of flexible anode.
2. 2. detection method as claimed in claim 1, it is characterised in that when the number of the potentiostat is " disconnected for multiple and nothing During electrical testing " function, the detection means also includes the synchronizing current relay being arranged on the anode cable.
3. 3. detection method as claimed in claim 1, it is characterised in that the spacing between two adjacent measurement points is 1 Rice.
4. 4. detection method as claimed in claim 1, it is characterised in that the measurement point is covered to the terminal position of flexible anode Put.