Method and system for evaluating service life of voltage-sharing electrode of converter valve

Abstract

The application provides a converter valve equalizing electrode service life evaluation method and system, and the method comprises the following steps: according to the actual voltage level of a converter station where the converter valve is located, the water pipe waterway cross section diameter, the length between two adjacent equalizing electrodes, the water pipe flow and the maximum allowable water temperature of the cooling water when the converter valve is running, an equivalent test platform of the equalizing electrode of the valve cooling system of the converter valve is built; the equivalent test platform is set with test current and test time, and the simulation running test of the equalizing electrode of the converter valve is carried out; the corrosion amount of the equalizing electrode is obtained by comparing the weight change amount of the equalizing electrode before and after the test; the test current and / or the test time of the equivalent test platform are changed, and the daily average corrosion amount of the equalizing electrode is obtained; the daily average corrosion amount is compared with the rated daily average corrosion amount, and the service life of the equalizing electrode after running is evaluated; the equalizing electrode can be effectively detected quickly before being put into operation to ensure that the equalizing electrode meets the requirements, so that the safe and reliable operation of the converter valve is ensured.

Description

Technical Field

[0001] This invention belongs to the field of flexible DC transmission technology, and more specifically, it relates to a method and system for evaluating the service life of equalizing electrodes for converter valves. Background Technology

[0002] The establishment of the Energy Internet has promoted the innovative development of flexible DC transmission technology. The core equipment of flexible DC transmission is the converter valve, and the cooling system is used to cool the main power components of the converter valve. In engineering, cooling water circuits are commonly used to dissipate heat and reduce the temperature of high-heat-generating components. To reduce the leakage current on the surface of the metal parts of the converter valve and thus inhibit corrosion, a certain number of equalizing electrodes are installed at specific locations in the water cooling system inside the converter valve.

[0003] Existing technologies mostly focus on software simulation calculations and electrolytic scaling deposition model analysis. Complex characterization methods have little practical engineering significance, and related simulation tests have long time cycles. There is a lack of effective means for building test platforms and evaluating the service life of equalizing electrodes for converter valves. Summary of the Invention

[0004] In view of this, the purpose of the present invention is to provide a method and system for evaluating the service life of the equalizing electrode of a converter valve, which is used to analyze and predict the aging and corrosion of the equalizing electrode through an equivalent test platform, evaluate the service life of the equalizing electrode, predict the failure time, thereby ensuring the safe and reliable operation of the converter valve, and thus avoiding the shutdown of the converter station caused by water leakage, blockage, and scale shedding due to the aging and corrosion of the equalizing electrode.

[0005] The first aspect of this application discloses a method for evaluating the service life of a pressure equalization electrode in a converter valve, comprising:

[0006] Based on the actual voltage level of the converter station where the converter valve is located, the cross-sectional diameter of the interlayer water pipe, the length between two adjacent equalizing electrodes, the water pipe flow rate, and the maximum allowable cooling water temperature during the operation of the converter valve, an equivalent test platform for the equalizing electrodes of the converter valve cooling system is built.

[0007] The equivalent test platform for the equalizing electrode of the converter valve cooling system was set with test current and test time to conduct a simulated operation test of the equalizing electrode of the converter valve; and the corrosion amount of the equalizing electrode was obtained by comparing the weight change of the equalizing electrode before and after the test.

[0008] By changing the test current and / or test time of the equivalent experimental platform for the equalizing electrode of the converter valve cooling system, the daily average corrosion amount of the equalizing electrode is obtained.

[0009] The daily average corrosion rate is compared with the rated daily average corrosion rate to evaluate the service life of the equalizing electrode of the converter valve after operation.

[0010] Optionally, in the above-mentioned method for evaluating the service life of the equalizing electrode of the converter valve, before setting the test current and test time on the equivalent test platform for the equalizing electrode of the converter valve cooling system, conducting a simulated operation test of the equalizing electrode of the converter valve, and obtaining the corrosion amount of the equalizing electrode by comparing the weight change of the equalizing electrode before and after the test, the method further includes:

[0011] Based on the arrangement of the equalizing electrodes of the converter valve, the maximum leakage current of the equalizing electrodes is determined.

[0012] Optionally, in the above-mentioned method for evaluating the service life of the equalizing electrode of the converter valve, the test current is less than or equal to the maximum leakage current.

[0013] Optionally, in the above-mentioned method for evaluating the service life of the equalizing electrode of the converter valve, determining the maximum leakage current of the equalizing electrode according to the arrangement scheme of the equalizing electrode of the converter valve includes:

[0014] Based on the arrangement scheme of the equalizing electrodes of the converter valve, the cold water circuit in the valve layer of the converter valve is transformed into an equivalent circuit model, and the maximum leakage current of the equalizing electrodes is calculated according to the maximum conductivity.

[0015] Optionally, in the above-mentioned method for evaluating the service life of the equalizing electrode of the converter valve, the cooling water circuit within the valve layer of the converter valve is transformed into an equivalent circuit model, including:

[0016] The equalizing electrode, the adjacent water pipe flange joint, the two adjacent flange joints on the main water pipe, and the water in the branch water pipe are equivalent to segments of small resistance.

[0017] Optionally, in the above-mentioned method for evaluating the service life of the equalizing electrode of the converter valve, the cooling water circuit within the valve layer of the converter valve is transformed into an equivalent circuit model, including:

[0018] Calculate the resistance of each section of the waterway;

[0019] Based on the resistance of each waterway section, calculate the voltage amplitude borne by each valve layer of the converter station valve tower.

[0020] Optionally, in the above-mentioned method for evaluating the service life of the equalizing electrode of the converter valve, the conductivity of the cooling water circuit during safe operation of the converter valve is 0.03-0.05 μs / cm, and the maximum allowable conductivity is 0.5 μs / cm.

[0021] Optionally, in the above-mentioned method for evaluating the service life of the equalizing electrode of the converter valve, the allowable temperature of the cooling water circuit during safe operation of the converter valve is 25-42℃, and the maximum allowable temperature is 50℃.

[0022] The second aspect of this application discloses a system for evaluating the service life of a pressure equalization electrode for a converter valve, comprising:

[0023] The unit is used to build an equivalent test platform for the equalizing electrodes of the converter valve cooling system based on the actual voltage level of the converter station where the converter valve is located, the cross-sectional diameter of the interlayer water pipe, the length between two adjacent equalizing electrodes, the water pipe flow rate, and the maximum allowable cooling water temperature when the converter valve is running.

[0024] The parameter setting unit is used to set the test current and test time for the equivalent test platform of the equalizing electrode of the converter valve cooling system, and to conduct a simulated operation test of the equalizing electrode of the converter valve; and to obtain the corrosion amount of the equalizing electrode by comparing the weight change of the equalizing electrode before and after the test; and to obtain the daily average corrosion amount of the equalizing electrode by changing the test current and / or test time of the equivalent test platform of the equalizing electrode of the converter valve cooling system.

[0025] The evaluation unit is used to compare the daily average corrosion amount with the rated daily average corrosion amount to evaluate the service life of the equalizing electrode of the converter valve after operation.

[0026] Optionally, the above-mentioned converter valve equalization electrode lifespan assessment system also includes:

[0027] The maximum value unit is used to determine the maximum leakage current of the equalizing electrode according to the arrangement scheme of the equalizing electrode of the converter valve.

[0028] As can be seen from the above technical solution, the method for evaluating the service life of the equalizing electrode of a converter valve provided by the present invention includes: constructing an equivalent test platform for the equalizing electrode of the converter valve cooling system based on the actual voltage level of the converter station where the converter valve is located, the cross-sectional diameter of the interlayer water pipe, the length between two adjacent equalizing electrodes, the water pipe flow rate, and the maximum allowable cooling water temperature during the operation of the converter valve; setting the test current and test time for the equivalent test platform for the equalizing electrode of the converter valve cooling system to conduct a simulated operation test of the equalizing electrode of the converter valve; obtaining the corrosion amount of the equalizing electrode by comparing the weight change of the equalizing electrode before and after the test; changing the test current and / or test time of the equivalent test platform for the equalizing electrode of the converter valve cooling system to obtain the daily average corrosion amount of the equalizing electrode; comparing the daily average corrosion amount with the rated daily average corrosion amount to evaluate the service life of the equalizing electrode of the converter valve after operation; thereby realizing the construction of an equivalent test platform for aging corrosion of the equalizing electrode of the converter valve, analyzing and predicting the aging corrosion of the equalizing electrode, effectively ensuring that the equalizing electrode meets the requirements before commissioning, thereby ensuring the safe and reliable operation of the converter valve. Attached Figure Description

[0029] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0030] Figure 1 This is a flowchart of a method for evaluating the service life of a pressure equalization electrode for a converter valve, provided in an embodiment of the present invention.

[0031] Figure 2 This is a schematic diagram of an equivalent test platform for equalizing electrodes of a converter valve cooling system provided in an embodiment of the present invention;

[0032] Figure 3 This is a flowchart of another method for evaluating the service life of the equalizing electrode of a converter valve provided in an embodiment of the present invention;

[0033] Figure 4 This is a schematic diagram of an equivalent circuit model of the cooling water path inside the valve layer of a converter valve provided in an embodiment of the present invention;

[0034] Figure 5 This is a flowchart of another method for evaluating the service life of the equalizing electrode of a converter valve provided in an embodiment of the present invention;

[0035] Figure 6 This is a schematic diagram of a converter valve equalization electrode life evaluation system provided in an embodiment of the present invention. Detailed Implementation

[0036] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0037] In this application, the terms "comprising," "including," or any other variations thereof are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0038] This application provides a method for evaluating the service life of the equalizing electrode of a converter valve, which addresses the problems in the prior art, such as the limited practical significance of complex characterization methods in software simulation calculations and electrolytic scaling deposition model analysis, the long time cycle of related simulation tests, and the lack of effective means for building a test platform and evaluating the service life of the equalizing electrode of a converter valve.

[0039] See Figure 1 The method for evaluating the service life of the equalizing electrode of the converter valve includes:

[0040] S101. Based on the actual voltage level of the converter station where the converter valve is located, the cross-sectional diameter of the interlayer water pipe, the length between two adjacent equalizing electrodes, the water pipe flow rate, and the maximum allowable cooling water temperature during the operation of the converter valve, build an equivalent test platform for the equalizing electrodes of the converter valve cooling system.

[0041] It should be noted that the framework of the equivalent test platform for the equalizing electrode of the converter valve cooling system can be pre-built; the parameters required for the equivalent test platform for the equalizing electrode of the converter valve cooling system, such as the actual voltage level of the converter station, the cross-sectional diameter of the interlayer water pipe, the length between two adjacent equalizing electrodes, the water pipe flow rate, and the maximum allowable cooling water temperature during the operation of the converter valve, are dynamically adjusted according to the actual situation. When prediction is needed, these parameters should be provided to dynamically adjust the construction of the equivalent test platform for the equalizing electrode of the converter valve cooling system.

[0042] In other words, parameters such as the actual voltage level of the converter station, the cross-sectional diameter of the interlayer water pipe, the length between two adjacent equalizing electrodes, the water pipe flow rate, and the maximum allowable cooling water temperature during the operation of the converter valve are input into the framework of the equivalent test platform for the equalizing electrodes of the converter valve cooling system, thereby realizing the dynamic adjustment of the equivalent test platform for the equalizing electrodes of the converter valve cooling system.

[0043] In addition, the parameters required for the equivalent test platform of the equalizing electrode of the converter valve cooling system may include other parameters, which will not be elaborated here. They can be determined according to the actual situation and are all within the protection scope of this application.

[0044] The methods for obtaining parameters such as the actual voltage level of the converter station, the cross-sectional diameter of the interlayer water pipe, the length between two adjacent equalizing electrodes, the water pipe flow rate, and the maximum allowable cooling water temperature during converter valve operation will not be elaborated here, but can be determined according to the actual situation, and are all within the scope of protection of this application.

[0045] It should be noted that the test platform uses the same type of equalizing electrodes and the same type of PVDF water pipes inside the valve tower. The diameter of the water pipes and the arrangement of the equalizing electrodes are consistent with those on the engineering site. A DC voltage is generated by a voltage source and applied between the electrodes at both ends of the water pipe channel in the valve tower. A current probe is connected to the low-voltage side to measure the current flowing through the electrodes.

[0046] For the specific structure of the equivalent test platform for the equalizing electrode of the converter valve cooling system, please refer to [link / reference]. Figure 2 As shown, 1-cooling water system, 2-voltage source, 3-current measurement, 4-equalizing electrode.

[0047] S102. Set the test current and test time for the equivalent test platform of the equalizing electrode of the converter valve cooling system, and conduct a simulated operation test of the equalizing electrode of the converter valve; and obtain the corrosion amount of the equalizing electrode by comparing the weight change of the equalizing electrode before and after the test.

[0048] It should be noted that the main function of the equalizing electrode is to release leakage current in the water, transferring it from the metal (aluminum, copper, stainless steel) of the electrical equipment to the inert (platinum) equalizing electrode, thus reducing corrosion of the electrical equipment. However, in actual operation, it has been found that after the leakage current is transferred to the surface of the equalizing electrode, it leads to aging, corrosion, scaling, and cracking of the electrode plating, seriously affecting the function and lifespan of the equalizing electrode. With the increasing number of DC transmission converter stations and the aging of equipment in early-operated converter stations, failures of key equipment in converter stations are becoming more frequent, with consequences ranging from converter valve tripping and emergency shutdowns to fires. Among the failures surveyed, problems caused by the valve internal water cooling system accounted for about 70% of all failures, all of which affected the operation of the converter valves to varying degrees. More than 25% of the failures in the valve internal water cooling circuit system were related to the aging, corrosion, and scaling of the equalizing electrode.

[0049] The test current is a value of the leakage current, that is, a current value of the test platform. The test platform generates a DC voltage through a voltage source, and the voltage is applied between the electrodes at both ends of the valve tower water pipe channel. The current probe is connected to the low-voltage side to measure the current flowing through the electrodes.

[0050] According to Faraday's law, the amount of corrosion is directly proportional to the leakage current; furthermore, it is also directly proportional to time. Additionally, the leakage current Imax of the equalizing electrode is the largest under conditions of maximum conductivity, resulting in the greatest corrosion. In actual engineering operations, conductivity remains within the normal range. This prediction platform calculates the maximum corrosion based on the most stringent (maximum) conductivity. In actual engineering operations, the corrosion amount will be less than or equal to the prediction value of this platform, increasing the reliability of the prediction.

[0051] It should be noted that Faraday's law describes the relationship between the amount of electricity passing through the electrode and the mass of the reactants at the electrode; it is also known as the law of electrolysis, as shown in the following formula:

[0052]

[0053] Wherein, W—mass of electrode reactants, in g; Q—total charge, in C; A—molar mass of the substance, in g / mol; F—Faraday constant, 9.65*10-4, in C / mol; n—valence of the metal; k—decomposition coefficient of the metal.

[0054] In the above formula, A, F, and n are all quantitative values, and k is the decomposition coefficient of the metal. Therefore, it can be concluded that the corrosion amount (mass of electrode reactants) W is directly proportional to Q, that is, directly proportional to the electrode current.

[0055] After accelerated aging tests are conducted on the equivalent test platform for the equalizing electrode of the converter valve cooling system, the mass of the equalizing electrode before and after the test can be compared using a high-precision electronic scale.

[0056] S103. Change the test current and / or test time of the equivalent test platform of the equalizing electrode of the converter valve cooling system to obtain the daily average corrosion amount of the equalizing electrode.

[0057] It should be noted that the test current can be changed only, the test time can be changed only, or both the test time and the test current can be changed simultaneously; no specific limitation is made here, it depends on the actual situation, and all are within the scope of protection of this application.

[0058] To ensure reliability, multiple sampling and testing were conducted on the same type of equalizing electrode. Different corrosion amounts were obtained by changing the current and time parameters. The daily average corrosion amount of the electrode was then calculated by combining the total corrosion amount with the total time, thus eliminating test errors and increasing reliability.

[0059] S104. Compare the daily average corrosion amount with the rated daily average corrosion amount to evaluate the service life of the equalizing electrode of the converter valve after operation.

[0060] This application pertains to accelerated electrode aging testing. Because actual engineering leakage currents are small, electrode corrosion is a slow and continuous process (generally measured in years). Therefore, if the test parameters are exactly the same, the predicted test time would also be measured in years. Thus, it is necessary to calculate and proportionally change parameters such as current and time to achieve the same corrosion rate; hence, this platform is for accelerated aging corrosion electrode testing.

[0061] By establishing an equivalent circuit model, the maximum leakage current of the equalizing electrode was calculated, and the accelerated aging corrosion effect was obtained by changing the current and time parameters using an experimental platform.

[0062] A data table of aging corrosion of equalizing electrodes was constructed, and its relationship with standard values ​​was determined to evaluate the service life of equalizing electrodes.

[0063] Considering only the electro-corrosion caused by the current multiplication effect, the acceleration factor of the test can be calculated, which is equivalent to aging corrosion over days. Based on the test results, the daily average corrosion amount equivalent to the actual current is calculated to be mg / day. According to relevant regulations, when the effective volume (mass) of the electrode decreases by more than 20%, the electrode needs to be replaced. Based on the specified 40-year operating requirements, the specified daily average corrosion amount Wa can be calculated. By comparing Wb and Wa, the service life of the pressure equalization electrode of the converter valve after operation is evaluated.

[0064] In practical applications, an aging and corrosion data table of equalizing electrodes can be constructed, and its relationship with standard quantities can be determined to assess the service life of the equalizing electrodes. This can effectively ensure that the equalizing electrodes meet the requirements for rapid testing before commissioning, thereby ensuring the safe and reliable operation of the converter valve.

[0065] In this embodiment, an equivalent test platform for the equalizing electrodes of the converter valve cooling system is constructed based on the actual voltage level of the converter station where the converter valve is located, the cross-sectional diameter of the interlayer water pipe, the length between two adjacent equalizing electrodes, the water pipe flow rate, and the maximum allowable cooling water temperature during the operation of the converter valve. A test current and test time are set for the equivalent test platform to simulate the operation of the equalizing electrodes. The corrosion amount of the equalizing electrodes is obtained by comparing the weight change of the equalizing electrodes before and after the test. The daily average corrosion amount of the equalizing electrodes is obtained by changing the test current and / or test time of the equivalent test platform. The daily average corrosion amount is compared with the rated daily average corrosion amount to evaluate the service life of the equalizing electrodes after operation. This achieves the construction of an equivalent test platform for the aging corrosion of the equalizing electrodes, enabling analysis and prediction of the aging corrosion of the equalizing electrodes. This effectively ensures that the equalizing electrodes meet the requirements for rapid detection before commissioning, thereby ensuring the safe and reliable operation of the converter valve.

[0066] In practical applications, see Figure 3 Before step S102, which involves setting the test current and test time on the equivalent test platform for the equalizing electrode of the converter valve cooling system, and conducting a simulated operation test of the equalizing electrode of the converter valve; and obtaining the corrosion amount of the equalizing electrode by comparing the weight change of the equalizing electrode before and after the test, the following steps are also included:

[0067] S201. Determine the maximum leakage current of the equalizing electrodes according to the arrangement scheme of the equalizing electrodes of the converter valve.

[0068] In other words, the maximum leakage current of the equalizing electrode is related to the arrangement of the equalizing electrode.

[0069] The specific relationship between the maximum leakage current of the equalizing electrode and the arrangement scheme of the equalizing electrode will not be elaborated here. It can be determined according to the actual situation, and all of them are within the protection scope of this application.

[0070] In practical applications, the test current is less than or equal to the maximum leakage current, thus ensuring that the test current is within the normal range of the equalizing electrodes.

[0071] In practical applications, the maximum leakage current of the equalizing electrodes is determined based on the arrangement scheme of the equalizing electrodes in the converter valve, including:

[0072] Based on the arrangement scheme of the equalizing electrodes of the converter valve, the cold water circuit in the valve layer of the converter valve is transformed into an equivalent circuit model, and the maximum leakage current of the equalizing electrodes is calculated according to the maximum conductivity.

[0073] In other words, the maximum leakage current is calculated based on the equivalent circuit model. The specific calculation process will not be elaborated here, but will depend on the actual situation, and is within the scope of protection of this application.

[0074] For the specific structure of the equivalent circuit model of the cooling water circuit within the valve layer of the converter valve, please refer to [link / reference]. Figure 4 As shown, R1-R13 are the equivalent resistances of the water circuit, V1-V8 are the equivalent power supplies, and probes 1-13 are the equalizing electrodes of the water circuit.

[0075] In practical applications, the cooling water circuit within the valve layer of the converter valve is transformed into an equivalent circuit model, including:

[0076] The equalizing electrode, the adjacent water pipe flange joint, the two adjacent flange joints on the main water pipe, and the water in the branch water pipe are considered as small resistances.

[0077] In other words, the method of equating the cold water circuit inside the valve layer of the converter valve to a circuit model is to equate the equalizing electrode, the adjacent water pipe flange joint, the two adjacent flange joints on the main water pipe, and the water in the branch water pipe to a series of small resistors.

[0078] In practical applications, the cooling water circuit within the valve layer of the converter valve is transformed into an equivalent circuit model, including:

[0079] Calculate the resistance of each section of the waterway: Where R is the waterway resistance, in MΩ; L is the waterway length, in cm; S is the waterway cross-sectional area, in cm²; and σ is the waterway conductivity, in μs / cm.

[0080] Based on the resistance of each waterway section, calculate the voltage amplitude borne by each valve layer of the converter station valve tower.

[0081] In practical applications, the conductivity of the cooling water circuit during safe operation of the converter valve is 0.03-0.05 μs / cm, with a maximum allowable conductivity of 0.5 μs / cm.

[0082] That is, the conductivity of the cooling water circuit during safe operation of the converter valve is 0.03-0.05 μs / cm, the maximum allowable conductivity is 0.5 μs / cm, and considering the most severe water environment conditions, the test conductivity is taken as 0.5 μs / cm.

[0083] In practical applications, the allowable temperature of the cooling water circuit during safe operation of the converter valve is 25-42℃, and the maximum allowable temperature is 50℃.

[0084] That is, the water temperature of the cooling water circuit when the converter valve is operating safely is generally 25-42℃. Considering the most severe water environment conditions, the test water temperature is taken as 50℃.

[0085] Specifically, such as Figure 5 The following example illustrates the specific process of a method for evaluating the service life of a pressure equalization electrode in a converter valve:

[0086] 1) For a converter station of a certain voltage level, according to the arrangement scheme of the equalizing electrodes of the converter valve.

[0087] The cooling water circuit within the valve layer is transformed into an equivalent circuit model, and the maximum leakage current of the equalizing electrode is calculated as Imax (mA) based on the maximum conductivity.

[0088] 2) Based on the actual voltage level of the converter station, the cross-sectional diameter of the interlayer water pipe, the length between two adjacent electrodes, the water pipe flow rate, and the extreme maximum allowable water temperature of the cooling water during the operation of the converter valve, build an equivalent test platform for the equalizing electrode of the converter valve cooling system.

[0089] 3) According to Faraday's law, the amount of corrosion is directly proportional to the leakage current. The equivalent test platform is set with a test current of I1 (mA) and a test time of t1 (h) to conduct a simulated operation test of the equalizing electrode of the converter valve.

[0090] 4) The amount of corrosion W is calculated by comparing the weight change of the equalizing electrode before and after the test.

[0091] 5) Compare the daily average corrosion amount Wb of the equalizing electrode of the valve cooling system after changing the test current and time parameters with the rated daily average corrosion amount Wa to evaluate the service life of the equalizing electrode of the converter valve after operation.

[0092] It should be noted that the electrode corrosion rate is calculated under different test currents and test times, and then the daily average corrosion rate is calculated. The rated daily average corrosion rate Wa is a value specified in engineering standards, not a calculated value.

[0093] Another embodiment of this application provides a system for evaluating the service life of a pressure equalization electrode for a converter valve.

[0094] See Figure 6 The lifespan assessment system for the equalizing electrode of the converter valve includes:

[0095] Unit 101 is used to build an equivalent test platform for the equalizing electrodes of the converter valve cooling system based on the actual voltage level of the converter station where the converter valve is located, the cross-sectional diameter of the interlayer water pipe, the length between two adjacent equalizing electrodes, the water pipe flow rate, and the maximum allowable cooling water temperature when the converter valve is running.

[0096] The parameter setting unit 102 is used to set the test current and test time for the equivalent test platform of the equalizing electrode of the converter valve cooling system, and to conduct a simulated operation test of the equalizing electrode of the converter valve; and to obtain the corrosion amount of the equalizing electrode by comparing the weight change of the equalizing electrode before and after the test; and to obtain the daily average corrosion amount of the equalizing electrode by changing the test current and / or test time of the equivalent test platform of the equalizing electrode of the converter valve cooling system.

[0097] Evaluation unit 103 is used to compare the daily average corrosion amount with the rated daily average corrosion amount to evaluate the service life of the equalizing electrode of the converter valve after operation.

[0098] In practical applications, this converter valve equalization electrode lifespan assessment system also includes:

[0099] The maximum value unit is used to determine the maximum leakage current of the equalizing electrodes based on the arrangement scheme of the equalizing electrodes of the converter valve.

[0100] In this embodiment, the construction unit constructs an equivalent test platform for the equalizing electrodes of the converter valve cooling system based on the actual voltage level of the converter station where the converter valve is located, the cross-sectional diameter of the interlayer water pipe, the length between two adjacent equalizing electrodes, the water pipe flow rate, and the maximum allowable cooling water temperature during the operation of the converter valve. The parameter setting unit sets the test current and test time for the equivalent test platform for the equalizing electrodes of the converter valve cooling system to conduct a simulated operation test of the equalizing electrodes of the converter valve. By comparing the weight change of the equalizing electrodes before and after the test, the corrosion amount of the equalizing electrodes is obtained. The test current and / or test time of the equivalent test platform for the equalizing electrodes of the converter valve cooling system are changed to obtain the daily average corrosion amount of the equalizing electrodes. The evaluation unit compares the daily average corrosion amount with the rated daily average corrosion amount to evaluate the service life of the equalizing electrodes of the converter valve after operation. This realizes the construction of an equivalent test platform for the aging corrosion of the equalizing electrodes of the converter valve, analyzes and predicts the aging corrosion of the equalizing electrodes, and can effectively ensure that the equalizing electrodes meet the requirements before commissioning, thereby ensuring the safe and reliable operation of the converter valve.

[0101] The features described in the various embodiments of this specification can be substituted for or combined with each other. Similar or identical parts between embodiments can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. In particular, for system or system embodiments, since they are basically similar to method embodiments, the description is relatively simple; relevant parts can be referred to the descriptions in the method embodiments. The systems and system embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art can understand and implement this without creative effort.

[0102] Those skilled in the art will further recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of both. To clearly illustrate the interchangeability of hardware and software, the components and steps of the various examples have been generally described in terms of functionality in the foregoing description. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementations should not be considered beyond the scope of this invention.

[0103] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for evaluating the service life of a pressure equalization electrode in a converter valve, characterized in that, include: Based on the actual voltage level of the converter station where the converter valve is located, the cross-sectional diameter of the interlayer water pipe, the length between two adjacent equalizing electrodes, the water pipe flow rate, and the maximum allowable cooling water temperature during the operation of the converter valve, an equivalent test platform for the equalizing electrodes of the converter valve cooling system was built. Based on the arrangement scheme of the equalizing electrodes of the converter valve, determine the maximum leakage current of the equalizing electrodes; Test current and test time were set on the equivalent test platform for the equalizing electrode of the converter valve cooling system, and a simulated operation test of the equalizing electrode of the converter valve was carried out; the corrosion amount of the equalizing electrode was obtained by comparing the weight change of the equalizing electrode before and after the test. By changing the test current and / or test time of the equivalent experimental platform for the equalizing electrode of the converter valve cooling system, the daily average corrosion amount of the equalizing electrode is obtained. The daily average corrosion rate is compared with the rated daily average corrosion rate to evaluate the service life of the equalizing electrode of the converter valve after operation.

2. The method for evaluating the service life of the equalizing electrode of the converter valve according to claim 1, characterized in that, The test current is less than or equal to the maximum leakage current.

3. The method for evaluating the service life of the equalizing electrode of the converter valve according to claim 2, characterized in that, Based on the arrangement of the equalizing electrodes of the converter valve, the maximum leakage current of the equalizing electrodes is determined, including: Based on the arrangement scheme of the equalizing electrodes of the converter valve, the cold water circuit in the valve layer of the converter valve is transformed into an equivalent circuit model, and the maximum leakage current of the equalizing electrodes is calculated according to the maximum conductivity.

4. The method for evaluating the service life of the equalizing electrode of the converter valve according to claim 3, characterized in that, The process of converting the cold water path within the valve layer of the converter valve into an equivalent circuit model includes: The equalizing electrode, the adjacent water pipe flange joint, the two adjacent flange joints on the main water pipe, and the water in the branch water pipe are equivalent to segments of small resistance.

5. The method for evaluating the service life of the equalizing electrode of the converter valve according to claim 4, characterized in that, The process of converting the cold water path within the valve layer of the converter valve into an equivalent circuit model includes: Calculate the resistance of each section of the waterway; Based on the resistance of each waterway section, calculate the voltage amplitude borne by each valve layer of the converter station valve tower.

6. The method for evaluating the service life of the equalizing electrode of the converter valve according to claim 5, characterized in that, When the converter valve is operating safely, the conductivity of the cooling water circuit is 0.03-0.05 μs / cm, and the maximum allowable conductivity is 0.5 μs / cm.

7. The method for evaluating the service life of the equalizing electrode of the converter valve according to claim 5, characterized in that, The allowable temperature of the cooling water circuit during safe operation of the converter valve is 25-42℃, and the maximum allowable temperature is 50℃.

8. A system for evaluating the service life of equalizing electrodes in a converter valve, characterized in that, include: The unit is used to build an equivalent test platform for the equalizing electrodes of the converter valve cooling system based on the actual voltage level of the converter station where the converter valve is located, the cross-sectional diameter of the interlayer water pipe, the length between two adjacent equalizing electrodes, the water pipe flow rate, and the maximum allowable cooling water temperature when the converter valve is running. The maximum value unit is used to determine the maximum leakage current of the equalizing electrode according to the arrangement scheme of the equalizing electrode of the converter valve. The parameter setting unit is used to set the test current and test time for the equivalent test platform of the equalizing electrode of the converter valve cooling system, and to conduct a simulated operation test of the equalizing electrode of the converter valve; and to obtain the corrosion amount of the equalizing electrode by comparing the weight change of the equalizing electrode before and after the test; and to obtain the daily average corrosion amount of the equalizing electrode by changing the test current and / or test time of the equivalent test platform of the equalizing electrode of the converter valve cooling system. The evaluation unit is used to compare the daily average corrosion amount with the rated daily average corrosion amount to evaluate the service life of the equalizing electrode of the converter valve after operation.

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