CN108303367A - The test device and method of the accelerated corrosion of metallic ground material and cathodic protection - Google Patents

Abstract

The invention provides a testing device and method for studying accelerated corrosion and cathodic protection of metal grounding materials by using a soil simulation solution. The device includes: a DC power supply, a main control module, a DC power supply controller and a corrosion test box. Corrosion test chambers include soil simulation solution corrosion test chamber, No. 1 soil corrosion test chamber and No. 2 soil corrosion test chamber. The methods include: 1. electrolytic accelerated corrosion and 2. cathodic protection. The present invention can study the acceleration of soil simulation solution, the mechanism and acceleration ratio of soil acceleration and soil non-acceleration, and then study the relationship between the energized voltage, current and time of soil simulation solution acceleration and the acceleration ratio of soil non-acceleration, and find the most Optimum power-on voltage, current and time, through the detection device provided by this application, the operation and maintenance cost is low, the detection result is reasonable, and the user experience is good.

Description

Test device and method for accelerated corrosion and cathodic protection of metal grounding materials

technical field

The invention relates to the technical field of grounding electrode corrosion detection of power transmission lines, in particular to a test device and method for accelerated corrosion and cathodic protection of metal grounding materials.

Background technique

The grounding grid for long-distance and large-capacity power transmission is an inevitable trend in the development of my country's future power grid. The grounding grid is directly related to the safe and stable operation of the grid equipment. In the power system, the grounding electrode is the main component of the grounding device and is buried in the soil. To ensure the safe and stable operation of the power grid and electrical equipment. Grounding electrodes are usually made of metal materials, and corrosion will inevitably occur due to the long-term underground dark and humid environment. The corrosion of metal materials in the soil will directly affect the service life and effect of the grounding grid, and when the working current or voltage of the grounding grid flows through the earth through the DC grounding electrode, the corrosion of the grounding electrode will be intensified. If the ground electrode of the tower is severely corroded, resulting in unsmooth flow, increased ground resistance, and thermal stability requirements cannot be met during operation. When a short circuit fault or lightning strike occurs in the power system, the ground potential rises, and high voltage enters the secondary circuit. It will cause more accidents.

At present, the main methods for corrosion detection of grounding electrodes include the analysis method based on network theory and the analysis method based on electromagnetic field theory. The former regards the grounding electrode as a pure resistance, uses the basic principles of circuit theory, establishes a grounding electrode corrosion detection project through certain measurement methods and calculation methods, and obtains the actual resistance value or resistance value change rate of each branch conductor by solving the diagnostic equation , and then judge the corrosion status; the latter mainly injects a certain frequency current into the grounding electrode, and measures the magnetic field strength of the grounding pole surface, and finally detects the degree of corrosion according to the distribution of the magnetic field.

However, in the actual operation and maintenance work of power companies, the judgment of grounding metal electrode corrosion cannot rely solely on analysis and guesswork, because the geographical environment of metal grounding materials is different, which will have an impact on the final result. In order to avoid this problem, most power companies have to adopt regular excavation methods, which is time-consuming, labor-intensive, blind, greatly affected by site operating conditions, and the overall operation and maintenance costs are high.

Therefore, the prior art urgently needs to provide a detection method and device for metal grounding materials under various environmental conditions such as accelerated corrosion and cathodic protection, so as to help provide a theoretical basis for achieving the best economic indicators for grounding engineering cathodic protection technology.

Contents of the invention

In order to solve the above technical problems, the present invention provides a test device and method for accelerated corrosion and cathodic protection of metal grounding materials. The research method provided by the present invention has comparability and operability, and can study soil simulation solution acceleration, soil acceleration and the mechanism and acceleration ratio of soil non-acceleration, and then study the relationship between the energized voltage, current, and time of soil simulation solution acceleration and the acceleration ratio of soil non-acceleration. Through the detection device provided by this application, the operation and maintenance cost is low, and the detection results Reasonable, good user experience.

In view of this, the present invention proposes a test device for accelerated corrosion and cathodic protection of metal grounding materials, the test device at least includes a DC power supply, a main control module, a DC power controller and a corrosion test chamber;

The DC power supply is connected to one end of the main control module, and is used to output a preset mode of DC power under the control of the main control module;

The other end of the main control module is connected to the input terminal of the DC power controller, so as to provide the DC power outputted by the DC power source to the DC power controller;

The output terminal of the DC power controller is connected to the corrosion test chamber, and is used to adjust the power parameters of the DC power supply to meet the test requirements of accelerated corrosion and cathodic protection of the metal grounding material to be tested;

The corrosion test chamber is used to construct at least one simulated soil corrosion test condition, and the metal grounding material to be tested is placed in the corrosion test chamber for accelerated corrosion and cathodic protection tests.

Further, the preset modes of the DC power supply include one or more of the following: municipal AC-DC power supply mode, photovoltaic-DC power supply mode, and photovoltaic-battery DC power supply mode.

Further, when the DC power supply outputs DC power in the municipal AC-DC power supply mode, the current loop composed of municipal AC power and a rectifier connected in series with the municipal AC power included in the DC power supply is connected;

When the DC power supply outputs DC power in the photovoltaic-DC power supply mode, the current loop connected in series by the solar photovoltaic panel, photovoltaic controller, inverter and rectifier included in the DC power supply is turned on;

When the DC power supply outputs DC power in the photovoltaic-battery DC power supply mode, the current loop included in the DC power supply, which is connected in series by the solar photovoltaic panel, the photovoltaic controller and the battery, is turned on.

Further, the corrosion test chamber includes three sub-test chambers of a soil simulation solution corrosion test chamber, a first soil corrosion test chamber, and a second soil corrosion test chamber; The soil simulation solution configured by the physical and chemical properties of the soil, the soil raw material sampled in the field is all configured in the first soil corrosion test box and the second soil corrosion test box;

The output end of the DC power controller is used to extend into the soil simulation solution corrosion test box and the second soil corrosion test box, to verify whether the soil simulation solution and the soil sampled in the field have a similar Test results; the first soil corrosion test chamber is used for data comparison under the non-electrolytic accelerated state with the other two test chambers.

Further, the DC power controller includes No. 1 DC power controller and No. 2 DC power controller, the No. 1 DC power controller extends into the soil simulation solution corrosion test chamber, and the No. 2 DC power controller The instrument is extended into the second soil corrosion test chamber.

Further, the testing device also includes an electrochemical workstation for connecting the output terminal of the DC power controller and the metal grounding material to be tested placed in the corrosion test chamber, and the metal grounding material to be tested includes research electrode and auxiliary electrode; the electrochemical workstation is used to collect the corrosion potential and corrosion current of the research electrode.

Further, a temperature measuring module and a temperature control module are also provided on the inner wall of the corrosion test chamber, and a heating module is also provided at the bottom of the corrosion test chamber, and the heating module is used to heat the corrosion test chamber , the temperature measurement module is used to detect the temperature in the corrosion test chamber, the temperature control module is electrically connected to the heating module and the temperature measurement module respectively, after the corrosion test chamber exceeds the preset temperature range , the temperature control module controls the heating module to stop heating or start heating, so that the test temperature of the corrosion test chamber remains within a preset temperature range.

Further, the material of the research electrode is Q235 type steel, the working area of the research electrode is 1 square centimeter, the back of the research electrode is connected to the electrochemical workstation through welding wires, and the non-working area of the research electrode is The surfaces are sealed with epoxy resin.

In the second aspect, the present application also provides a test method for accelerated corrosion of metal grounding materials based on the test device described above, the method comprising:

The main control module determines the power supply mode of the DC power supply;

The DC power source outputs the DC power in the power supply mode to the DC power controller;

Adjusting the power parameters of the DC power supply through the DC power controller, and performing an accelerated corrosion test on the metal grounding material to be tested placed in the corrosion test chamber;

Based on the experimental parameters recorded during the accelerated corrosion test, the degree of corrosion of the metal grounding material is determined.

In the third aspect, the present application also provides a test method for increasing cathodic protection of metal grounding materials in the process of accelerated corrosion based on the above-mentioned test device, the method comprising:

The main control module determines the power supply mode of the DC power supply;

The DC power source outputs the DC power in the power supply mode to the DC power controller;

The power supply parameters of the DC power supply are adjusted by the DC power supply controller, and during the accelerated corrosion test of the metal grounding material to be tested in the corrosion test chamber, record switching is provided to the metal grounding material to be tested. The comparison data obtained after the positive and negative poles of the power supply;

Based on the comparison data, the corrosion degree of the metal grounding material is determined, and the cathodic protection effect of the metal grounding material to be tested in the corrosion test chamber is verified.

In this technical solution, by adopting the test device and test method constructed in the embodiment of the present application, on the one hand, electrolytic accelerated corrosion can be used to accelerate the corrosion of the soil simulation solution and the research electrodes in the soil. The degree of corrosion can be judged by methods such as surface appearance, and the relationship between the accelerated voltage, current, and time of soil simulated solution and the acceleration ratio of non-accelerated soil is studied. At the same time, the cathodic protection verification test is carried out on the soil simulated solution and the research electrode in the soil, and the cathodic protection effect is judged by means of electrochemical polarization, impedance, weight loss, corrosion morphology, etc., and the soil simulated solution cathodic protection, soil cathodic protection and soil are studied. The unprotected mechanism and protection effect can finally effectively provide a theoretical basis for the realization of the best technical and economic indicators for the grounding engineering cathodic protection technology.

Description of drawings

FIG. 1 is a schematic structural view of a detection device described in an embodiment of the present invention;

Fig. 2 is the structural representation of the corrosion test box described in the embodiment of the present invention;

Among them, 1 is the solar photovoltaic panel, 2 is the photovoltaic controller, 3 is the inverter, 4 is the storage battery, 5 is the rectifier, 6 is the municipal AC power, 7 is the main control module, 8 is the No. 1 DC power controller, and 9 is the No. 2 DC power supply controller, 10 is the corrosion test chamber, 11 is the soil simulation solution corrosion test chamber, 12 is the No. 1 soil corrosion test chamber, 13 is the No. 2 soil corrosion test chamber, 14 is the temperature measurement module, and 15 is the heating module , 16 is a platinum electrode, 17 is a reference electrode, 18 is a research electrode, 19 is an auxiliary electrode, 20 is an electrochemical workstation, 21 is a temperature control module, 111 is a DC power supply, and 222 is a DC power controller.

Detailed ways

In order to understand the above-mentioned purpose, features and advantages of the present invention more clearly, the present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

In the following description, many specific details are set forth in order to fully understand the present invention, but the present invention can also be implemented in other ways different from those described here, therefore, the present invention is not limited to the specific embodiments disclosed below limit.

The present application provides a test device for accelerated corrosion and cathodic protection of metal grounding materials. As shown in FIG. Module 7, DC power supply controller 222 (shown in the dotted line frame of reference number 222 in the figure) and corrosion test chamber 10;

The DC power supply 111 is connected to one end of the main control module 7, and is used to output a preset mode of DC power under the control of the main control module 7;

One end of the main control module 7 is connected to the DC power supply, and the other end is connected to the input end of the DC power controller 222, so as to provide the DC power outputted by the DC power supply 111 to the DC power controller 222 ;

The output end of the DC power supply controller 222 is connected to the corrosion test chamber 10, and is used to adjust the power parameters of the DC power supply to control the accelerated corrosion of the metal grounding material to be tested and the test requirements for cathodic protection; wherein , the power supply parameters may include but not limited to voltage parameters, current parameters, and power supply parameters.

The corrosion test chamber 10 is used to construct at least one simulated soil corrosion test condition, and the metal grounding material to be tested is placed in the corrosion test chamber 10 for accelerated corrosion and cathodic protection tests. .

The grounding grid is directly related to the safe and stable operation of power grid equipment. The corrosion of metal materials in the soil directly affects the service life and effect of the grounding grid. It is of practical and long-term significance to study the accelerated corrosion of metal grounding materials and cathodic protection.

Further, the preset modes of the DC power supply 111 include one or more of the following: municipal AC-DC power supply mode, photovoltaic-DC power supply mode, and photovoltaic-battery DC power supply mode;

When the DC power supply outputs DC power in the municipal AC-DC power supply mode, the DC power supply includes a current loop composed of municipal AC power and a rectifier connected in series with the municipal AC power, and is connected;

When the DC power supply outputs DC power in the photovoltaic-DC power supply mode, the current loop in the DC power supply including the series connection of solar photovoltaic panels, photovoltaic controllers, inverters and rectifiers is turned on;

When the DC power supply outputs DC power in a photovoltaic-battery DC power supply mode, the DC power supply includes a current loop connected in series by a solar photovoltaic panel, a photovoltaic controller, and a battery.

As an example, refer to the circuit system of a DC power supply shown in Figure 1, that is, the DC power supply 111 is composed of three power supply systems: municipal AC-DC power supply system, photovoltaic-DC power supply system, photovoltaic-battery battery DC system.

Municipal AC-DC power supply system includes municipal AC 6 and rectifier 5;

The photovoltaic-DC power supply system includes a solar photovoltaic panel 1, a photovoltaic controller 2, an inverter 3 and a rectifier 5;

The photovoltaic-battery DC system includes a solar photovoltaic panel 1 , a photovoltaic controller 2 and a battery 4 .

Based on the three sets of DC power supply modes provided by the DC power supply source 111, different power supply modes can be used in different environmental conditions. For example, in a sunny environment, the photovoltaic-DC power supply mode can be selected preferentially. Under the environment, the municipal AC-DC power supply mode can be preferred, while the photovoltaic-battery mode can be used as an alternative in special environments to prevent the other two power supply systems from being unable to provide sufficient power.

Further, the corrosion test box 10 includes three sub-test boxes consisting of a soil simulation solution corrosion test box 11, a first soil corrosion test box 12, and a second soil corrosion test box 13; the soil simulation solution corrosion test box 11 The soil simulation solution configured based on the physical and chemical properties of the actual soil is configured in the chamber, and the soil materials sampled in the field are configured in the first 12 soil corrosion test chambers and the second soil corrosion test chamber 13 . To sum up, among the three corrosion test chambers, one is equipped with soil simulation solution, and the other two are equipped with real soil (one is non-accelerated and the other is accelerated).

The output end of the DC power controller 222 is used to extend into the soil simulation solution corrosion test box and the second soil corrosion test box, to verify whether the soil simulation solution and the soil sampled in the field have a similar The test results; the first soil corrosion test chamber is used for data comparison under the non-electrolytic accelerated state with the other two test chambers.

The soil simulated solution method is based on the physical and chemical properties of the actual soil, and the simulated corrosion test of the test piece is carried out. The ion concentration in the corrosion medium can be controlled, and the test environment is relatively stable, so the influence of ion concentration on the corrosion process can be studied. In order to accelerate the corrosion process, the corrosion rate can also be increased by increasing the ion concentration and other methods.

The purpose of this application is to use soil simulation solution as a corrosion medium to study accelerated corrosion and cathodic protection of metal grounding materials. Because the soil is taken from the site, the operation is troublesome, time-consuming and laborious. By configuring the soil simulation solution corrosion test chamber, we use the solution configured in the laboratory to replace the soil, so that the results obtained are true and reliable. At the same time, in order to speed up the experimental results, it is necessary to add the intermediate link of comparing soil acceleration and non-acceleration.

The DC power controller 222 includes No. 1 DC power controller 8 and No. 2 DC power controller 9, the No. 1 DC power controller 8 is used to adjust the power parameters of the soil simulation solution corrosion test chamber 11, The No. 2 DC power controller 9 is used to adjust the power parameters of the second soil corrosion test chamber 13; the No. 1 DC power controller 8 extends into the soil simulation solution corrosion test chamber 11, and the 2 No. DC power supply controller 9 extends into the second soil corrosion test chamber 13.

Among them, the principle of accelerated corrosion is to use electrochemical workstation, weight loss, corrosion morphology and other means to determine the degree of corrosion. This accelerated corrosion method can study the mechanism and acceleration ratio of soil simulated solution acceleration, soil acceleration and soil non-acceleration. It is mainly to study the accelerated and non-accelerated corrosion mechanism of soil simulated solution (means: XRD, scanning electron microscope), and the acceleration ratio (electrochemical workstation: polarization curve, impedance spectrum, corrosion).

The principle of cathodic protection is to use electrochemical workstation, weight loss, corrosion morphology and other means to determine the cathodic protection effect in soil simulation solution, and determine the optimal protection current and protection voltage after the required protection effect is achieved. The values of the optimum protection current and protection voltage, and the optimum protection current and protection voltage corresponding to different soils (the configured soil simulation solutions are also different). That is to say, different soils (different soil simulation solutions) have different protective voltages and protective currents.

Further, as shown in Figure 2, the detection device also includes an electrochemical workstation 20 for connecting the output end of the DC power controller and the metal grounding material to be tested placed in the corrosion test chamber, the The metal grounding material to be tested includes a research electrode 18 and an auxiliary electrode 19 ; the electrochemical workstation 20 is used to collect the corrosion potential and corrosion current of the research electrode 18 .

In the field of electrochemical technology, all electrochemical systems must contain at least two electrodes immersed in the electrolyte solution or closely attached to the electrolyte, that is, a two-electrode system, which includes the research electrode 18 and the auxiliary electrode 19 .

The electrochemical system realizes the input or output of electrical energy by means of electrodes, and the electrodes are the places where the electrode reactions are carried out.

In the test device and method provided in this application, if in the process of verifying the effect of accelerated corrosion and cathodic protection of the grounded metal material, no large current is applied to the grounded metal material, that is, when there is no current or a weak current passes through the electrochemical system , the potential of the research electrode 18 can be directly and accurately measured by the counter electrode, so a two-electrode system can be used.

Preferably, in order to achieve a more accurate test effect, a three-electrode system can be used. Referring to Fig. 2, one or two reference electrodes or platinum electrodes are added on the basis of the current electrodes, and the corresponding three electrodes are the research electrode 18, the reference electrode 17, the platinum electrode 16 and the auxiliary electrode 19.

Its working principle is that when a current passes through the electrochemical system, a voltage drop and polarization to the electrode are generated, so the potential of the research electrode 18 is difficult to accurately measure, thus introducing a reference electrode 17 and a platinum electrode 16, the reference electrode 17 and the platinum electrode 16 have a very stable potential, and the current does not cause polarization without passing through the reference electrode 17 and the platinum electrode 16, so the potential of the research electrode 18 can be obtained by the reference electrode, and the current is assisted by the research electrode 18- The circuit formed by the electrodes 19 is obtained.

By adopting the three-electrode system, the potential and current of the research electrode 18 can be measured conveniently and accurately.

Since the three-electrode system is a common test method in the field of electrochemical testing, its principle will not be described in detail here.

Further, a temperature measurement module 14 and a temperature control module 21 are also provided on the inner sidewall of the corrosion test chamber 10, and a heating module 15 is also provided at the bottom of the corrosion test chamber 10, and the heating module 15 is used to control the temperature of the corrosion test chamber 10. The corrosion test chamber 10 is heated, and the temperature measurement module 14 is used to detect the temperature in the corrosion test chamber 10. The temperature control module 21 is electrically connected with the heating module 15 and the temperature measurement module 14 respectively. After the corrosion test chamber 10 exceeds the preset temperature range, the heating module 15 is stopped or started to heat through the temperature control module 21, so that the test temperature of the corrosion test chamber 10 remains within the preset temperature range.

Further, the material of the research electrode 18 is Q235 type steel, the working area of the research electrode 18 is 1 square centimeter, the back side of the research electrode 18 is connected with the electrochemical workstation 20 by welding wires, the research electrode The non-working surface of 18 is sealed by epoxy resin.

On the basis of the test device provided by the present application, the present invention also provides a test method for accelerated corrosion of metal grounding materials, said method comprising:

Step 100, the main control module determines the power supply mode of the DC power supply;

Step 101, the DC power supply source outputs the DC power in the power supply mode to the DC power controller;

Step 102, adjusting the power parameters of the DC power supply through the DC power supply controller, and performing an accelerated corrosion test on the metal grounding material to be tested placed in the corrosion test chamber;

Step 103, based on the experimental parameters recorded during the accelerated corrosion test, determine the corrosion degree of the metal grounding material.

On the basis of the test device provided by the present application, the present application also provides a test method for increasing cathodic protection of metal grounding materials during accelerated corrosion, the method comprising:

Step S200, the main control module determines the power supply mode of the DC power supply;

Step S201, the DC power supply source outputs the DC power in the power supply mode to the DC power controller;

Step S202, adjusting the power parameters of the DC power supply through the DC power supply controller, and during the accelerated corrosion test of the metal grounding material to be tested in the corrosion test chamber, recording switching is provided to the metal to be tested The comparative data obtained after the positive and negative poles of the power supply of the grounding material;

Step S203, based on the comparison data, determine the corrosion degree of the metal grounding material, and verify the cathodic protection effect of the metal grounding material to be tested in the corrosion test chamber.

For the accelerated corrosion process of grounded metal materials, when the external power supply is connected to the protective electrode, the essential principle is to make the protected electrode continuously lose electrons and be corroded at an accelerated rate, so as to achieve the purpose of the experiment as soon as possible.

It is known from the principle of cathodic protection that applying cathodic current to the protected metal structure from an external DC power source can cause cathodic polarization to reduce or even completely inhibit metal corrosion. Its essential principle is to make the protected electrode continuously donate electrons to compensate for the corrosion process.

This determines the three components of the impressed current cathodic protection system: DC power supply, auxiliary anode and protected cathode. In the impressed current cathodic protection system, a stable and reliable DC power supply is required to supply the current for protection.

The requirements for the DC power supply are as follows:

(1) It can adapt to the on-site working environment (temperature, humidity, sunshine, wind and sand), and can work safely and reliably during long-term operation;

(2) Ensure that there is a large enough output current, and it can be adjusted in a wide range;

(3) There is a high enough output voltage to overcome the resistance in the system, and the output impedance should match the loop resistance;

(4) Easy to install, easy to operate, no need for frequent maintenance.

In the impressed current cathodic protection system, the electrode connected to the positive pole of the DC power supply is called the auxiliary anode. Its function is to enable the external cathode current to flow from the anode to the protected body through the medium, forming a current loop.

The basic principle of the electrolytic accelerated corrosion test is to apply an external voltage between the research electrode and the auxiliary electrode to form an electrolytic cell. The positive electrode of the power supply is connected to the research electrode, and its negative electrode is connected to the auxiliary electrode to form a voltage in the same direction as the electromotive force in the electrolytic cell. Decrease; the oxidizing ions with high electrode potential are discharged and reduced at the cathode, while the more active metals with low electrode potential in the anode area (relative to the elements in the anode area) lose electrons and are oxidized, becoming cations and detaching from the surface of the material, forming anode corrosion.

Electrochemical testing is mainly to study the measurement methods of material corrosion degree, corrosion rate and corrosion characteristics in accelerated corrosion test, mainly including the following four methods:

① Potential-time curve method, by monitoring the change of the self-corrosion potential of the metal with time, the corrosion of the metal can be understood.

②Polarization curve method, the relationship curve between polarization potential and polarization current is called polarization curve, and the polarization measurement near the corrosion potential can quickly obtain the corrosion rate and obtain the main parameters of electrochemical protection.

③Electrochemical Impedance Spectroscopy, using a small-amplitude AC signal to disturb the electrode, measuring how the system follows the disturbance in a steady state, and obtaining the electrochemical impedance spectrum of the electrode, so as to calculate the electrochemical parameters of the electrode.

④ Electrochemical noise method, which analyzes the noise spectrum of a random spontaneous fluctuation of potential or current that appears on the surface of the corroded electrode, and gives the corrosion process and characteristics of the material.

The device provided by the invention has the advantages of automatic temperature control, simple structure, simple operation, and integration of acceleration and cathodic protection.

The research method provided by the present invention is electrolytic accelerated corrosion. According to the test platform of the test device, the corresponding soil simulation solution is prepared according to the physical and chemical properties of the actual soil. The positive pole of the power supply is connected to the research electrode, and the negative pole is connected to the auxiliary electrode. After the system is stable, adjust the No. 1 DC power controller and No. 2 DC power controller to accelerate the corrosion of the research electrodes in the soil simulation solution and in the soil, and determine the degree of corrosion by means of electrochemical, weight loss, and corrosion morphology.

The invention provides a cathodic protection method for researching metal grounding materials. According to the test device, the test platform is built, and the corresponding soil simulation solution is prepared according to the actual physical and chemical properties of the soil. The positive pole of the power supply is connected to the auxiliary electrode, and the negative pole is connected to the research electrode. After each system is stable, adjust the No. 1 DC power controller and No. 2 DC power controller to carry out cathodic protection on the soil simulation solution and the research electrodes in the soil, and use the electrochemical workstation, weight loss, corrosion morphology and other means to determine the cathodic protection. Effect.

The research cathodic protection method provided by the invention can study the mechanism and protection effect of soil simulated solution cathodic protection, soil cathodic protection and soil unprotected.

Monitor and study the voltage and current required for the best protection effect of the electrode, monitor the power supply of the three power supply systems, and make reasonable adjustments to provide a theoretical basis for the grounding engineering cathodic protection technology to achieve the best technical and economic indicators.

In order to further illustrate the present invention, a kind of device that utilizes soil simulation solution to study the accelerated corrosion of metal grounding material and cathodic protection that the present invention provides is described in detail below in conjunction with embodiment, but they can not be interpreted as the limitation of protection scope of the present invention.

Example 1:

According to the physical and chemical properties of a substation soil and other characteristics, the corresponding soil simulation solution was prepared, and the composition is shown in Table 1.

Table 1 Components of soil simulation solution

NaCl _CaCl2 MgSO ₄ 7H ₂ O NaHCO ₃ Na ₂ SO ₄ KNO ₃ pH 0.0352g/L 0.0249g/L 0.0249g/L 0.0117g/L 0.0134g/L 0.0257g/L 4.48

According to the test device structure diagram 1, the test device platform is built.

A number of Q235 steel research electrodes were prepared, the working area was 1cm ² , the wires were welded on the back, and the non-working surface was sealed with epoxy resin.

Install the Q235 steel research electrodes in the research electrode slots of the soil simulation solution corrosion test box, the first soil corrosion test box and the second soil corrosion test box respectively, and install the platinum electrode and the reference electrode in their respective card slots. At the groove, the research electrode, the platinum electrode and the reference electrode form a three-electrode system. Install the auxiliary electrode in the soil simulation solution corrosion test box and the auxiliary electrode slot in the soil corrosion test box.

Control the heating module and the temperature measuring module so that the temperature of the whole test is kept constant at 25°C±0.1°C.

After the electrode under study was naturally corroded for 24 hours, the whole system was stabilized, and parameters such as corrosion potential and corrosion current of the electrode were measured by electrochemical workstation.

After the test is completed, provide a corrosion current of 100mA/m ² to the research electrodes of the soil simulation solution corrosion test box and the second soil corrosion test box. According to the test requirements, determine the time to provide corrosion current, measure the "initial" potential value at the moment of power-off of the accelerated corrosion research electrode and the potential value after 3 hours, and use the Tafel polarization curve method to measure parameters such as corrosion current density.

Table 2 shows the corrosion current density of the research electrode for 24 hours of natural corrosion, and Table 3 shows the corrosion current density of the research electrode after 3 hours of power failure. From Table 2, it can be concluded that the corrosion rate of the Q235 steel research electrode in the soil simulation solution and soil is almost the same , which shows that the soil simulation solution can reflect the corrosion status of metals in soil. It can be concluded from Table 3 that the corrosion current density of the research electrode in the second soil corrosion test chamber and the soil simulation solution corrosion test chamber is roughly the same, which is about one time of the corrosion density of the research electrode in the first soil corrosion test chamber, indicating that in the soil The metal in the simulated solution undergoes galvanic corrosion, and its corrosion rate doubles.

Table 2 The corrosion current density of the electrode under natural corrosion for 24 hours

Table 3 Corrosion current density of research electrode after 3h power off

Example 2:

As in Example 1, only the accelerated corrosion time of the external power supply is changed, and the corrosion time of the external power supply is double that of Example 1. Table 4 shows the corrosion current density of the research electrode after 3 hours of power failure. It can be concluded from Table 4 that the corrosion current density of the grounding material in the soil simulated solution corrosion test box is roughly the same as that in the second soil corrosion test box, which is about the same as that of the first soil corrosion test box. 4 times the corrosion current density of the ground material in the corrosion test chamber.

It can be known from Example 1 and Example 2 that under the same circumstances, the longer the corrosion acceleration energization time, the greater the corrosion acceleration, which is a direct proportional relationship. To ensure its accuracy, a correction factor can be added.

Table 4 Corrosion current density of research electrode after 3h power off

Example 3:

As in Example 1, the positive and negative poles of the DC source applied to the research electrode and the auxiliary electrode are only changed by the No. 1 DC power controller and the No. 2 DC power controller. Table 5 shows the corrosion current density of the research electrode after 3h of power failure. It can be seen from Table 5 that the corrosion current density of the soil simulated solution corrosion test box and the second soil corrosion test box are almost the same, while the first soil corrosion test box is 1.5 times that of the two, so the life of the grounding material is that without cathodic protection 1.5 times the life of the grounding material. Implementing impressed current cathodic protection in soil simulated solution environment can verify the actual cathodic protection effect.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and changes. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims (10)

1. A test device for accelerated corrosion of metal grounding materials and cathodic protection, characterized in that the test device at least includes a DC power supply, a main control module, a DC power controller and a corrosion test chamber; The DC power supply is connected to one end of the main control module, and is used to output a preset mode of DC power under the control of the main control module; The other end of the main control module is connected to the input terminal of the DC power controller, so as to provide the DC power outputted by the DC power source to the DC power controller; The output terminal of the DC power controller is connected to the corrosion test chamber, and is used to adjust the power parameters of the DC power supply to meet the test requirements of accelerated corrosion and cathodic protection of the metal grounding material to be tested; The corrosion test chamber is used to construct at least one simulated soil corrosion test condition, and the metal grounding material to be tested is placed in the corrosion test chamber for accelerated corrosion and cathodic protection tests. 2. The test device according to claim 1, wherein the preset modes of the DC power supply include one or more of the following: Municipal AC-DC power supply mode, photovoltaic-DC power supply mode, photovoltaic-battery DC power supply mode. 3. The test device according to claim 2, characterized in that, when the DC power supply outputs DC power in the municipal AC-DC power supply mode, the municipal AC power included in the DC power supply and the The rectifiers connected in series with alternating current form a current loop and are connected; When the DC power supply outputs DC power in the photovoltaic-DC power supply mode, the current loop connected in series by the solar photovoltaic panel, photovoltaic controller, inverter and rectifier included in the DC power supply is turned on; When the DC power supply outputs DC power in the photovoltaic-battery DC power supply mode, the current loop included in the DC power supply, which is connected in series by the solar photovoltaic panel, the photovoltaic controller and the battery, is turned on. 4. test device according to claim 1, is characterized in that, described corrosion test box comprises soil simulated solution corrosion test box, the first soil corrosion test box and three sub-test boxes of the second soil corrosion test box; The soil simulation solution corrosion test box is equipped with a soil simulation solution based on the physical and chemical properties of the soil sampled in the field, and the first soil corrosion test box and the second soil corrosion test box are equipped with soil raw materials sampled in the field; The output end of the DC power controller is used to extend into the soil simulation solution corrosion test box and the second soil corrosion test box, to verify whether the soil simulation solution and the soil sampled in the field have a similar Test results; the first soil corrosion test chamber is used for data comparison under the non-electrolytic accelerated state with the other two test chambers. 5. The test device according to claim 4, wherein the DC power controller includes No. 1 DC power controller and No. 2 DC power controller, and the No. 1 DC power controller extends into the soil To simulate a solution corrosion test chamber, the No. 2 DC power supply controller extends into the second soil corrosion test chamber. 6. test device according to claim 1, is characterized in that, described test device also comprises the output end that is used to connect described DC power controller and is placed in the metal grounding material to be tested in described corrosion test box An electrochemical workstation, the metal grounding material to be tested includes a research electrode and an auxiliary electrode; the electrochemical workstation is used to collect the corrosion potential and corrosion current of the research electrode. 7. The test device according to claim 1 or 4, characterized in that, a temperature measuring module and a temperature control module are also provided on the inner wall of the corrosion test chamber, and a heating module is also provided at the bottom of the corrosion test chamber , the heating module is used to heat the corrosion test chamber, the temperature measurement module is used to detect the temperature in the corrosion test chamber, the temperature control module is connected with the heating module and the temperature measurement module respectively Electrical connection, after the corrosion test chamber exceeds the preset temperature range, the temperature control module controls the heating module to stop heating or start heating, so that the test temperature of the corrosion test chamber remains within the preset temperature range . 8. test device according to claim 6, is characterized in that, the material of described research electrode is Q235 model steel, the working area of described research electrode is 1 square centimeter, the back side of described research electrode is connected with the described research electrode by welding wire. The electrochemical workstation is connected, and the non-working surface of the research electrode is sealed by epoxy resin. 9. A test method for accelerated corrosion of metal grounding materials based on the test device described in any one of claims 1 to 8, characterized in that the method comprises: The main control module determines the power supply mode of the DC power supply; The DC power source outputs the DC power in the power supply mode to the DC power controller; Adjusting the power parameters of the DC power supply through the DC power controller, and performing an accelerated corrosion test on the metal grounding material to be tested placed in the corrosion test chamber; Based on the experimental parameters recorded during the accelerated corrosion test, the degree of corrosion of the metal grounding material is determined. 10. A test method for adding cathodic protection to metal grounding materials during accelerated corrosion process based on the test device described in any one of rights 1 to 8, characterized in that the method comprises: The main control module determines the power supply mode of the DC power supply; The DC power source outputs the DC power in the power supply mode to the DC power controller; The power supply parameters of the DC power supply are adjusted by the DC power supply controller, and during the accelerated corrosion test of the metal grounding material to be tested in the corrosion test chamber, record switching is provided to the metal grounding material to be tested. The comparison data obtained after the positive and negative poles of the power supply; Based on the comparison data, the corrosion degree of the metal grounding material is determined, and the cathodic protection effect of the metal grounding material to be tested in the corrosion test chamber is verified.