A method and device for detecting an electrode scale layer of a converter valve

Abstract

The present application belongs to the technical field of cooling control of converter valve, and particularly relates to a method and device for detecting scale layer of voltage-sharing electrode of converter valve. The scale layer resistance threshold is set as the scale layer resistance reaching the maximum allowable leakage current between the metal pipeline and the deionized water, the voltage-sharing electrodes symmetrically arranged in the converter valve tower are selected, when there is only one voltage-sharing electrode arranged in the same section of the water pipe of the converter valve tower, one of the voltage-sharing electrodes is a measuring electrode, and the other is a reference electrode; the loop resistance of the measuring electrode and the loop resistance of the reference electrode are respectively tested, the jumpers corresponding to the voltage-sharing electrodes are respectively removed during the test, the difference between the loop resistance of the measuring electrode and the loop resistance of the reference electrode is calculated, the difference is taken as the scale layer resistance, and the scale layer resistance is compared with the scale layer resistance threshold to determine the scale condition of the voltage-sharing electrode of the converter valve. The voltage-sharing electrode does not need to be disassembled, the structure of the voltage-sharing electrode is not damaged, and the obtained scale layer condition is more accurate.

Description

Technical Field

[0001] This invention belongs to the field of converter valve cooling control technology, specifically relating to a method and device for detecting scale on the equalizing electrode of a converter valve. Background Technology

[0002] Converter valves are critical components in high-voltage direct current (HVDC) transmission systems. During operation, these components generate significant heat, necessitating a valve cooling system. This system uses circulating cooling water to remove heat from the converter valve assembly. Heat is then exchanged within the aluminum alloy radiator and discharged to the environment, ensuring the valve's proper functioning. Deionized water, typically with a conductivity of 0.1 μS / cm–0.5 μS / cm, is generally used for cooling. Because the cooling water flows through metal components at different potentials (including pipes, radiators, and other metal parts), leakage currents can occur due to the high voltage and complex electromagnetic field environment between these components, leading to electrolytic corrosion. To address this, existing technologies typically incorporate equalizing electrodes in the converter valve cooling system's water circuit. These electrodes transfer leakage current from the metal to the inert electrodes, ensuring that the metal components have the same potential through the equipotential lines, thus preventing corrosion.

[0003] During operation, the equalizing electrode continuously accumulates scale. Scale shedding can cause electrode failure, leading to corrosion of metal water pipes and potential blockage of internal cooling water pipes, ultimately damaging valve tower equipment. Therefore, it is crucial to monitor the scale buildup on the equalizing electrode and remove it promptly. Current technology involves periodically inspecting the equalizing electrode by disassembling it after draining water, measuring its thickness, and using mechanical methods to remove scale. However, disassembling the equalizing electrode is cumbersome, and relying solely on thickness measurement for scale buildup is inaccurate. Repeated disassembly can loosen sealing gaskets, resulting in inefficient scale inspection and potential damage to the equalizing electrode. Summary of the Invention

[0004] The purpose of this invention is to provide a method and apparatus for detecting scale on the equalizing electrode of a converter valve, so as to solve the problems of low detection efficiency, low accuracy and easy damage to the equalizing electrode when the equalizing electrode is disassembled and the scale is detected according to the thickness of the equalizing electrode.

[0005] This invention provides a method for detecting scale buildup on the equalizing electrode of a converter valve to solve the aforementioned technical problems. The method includes: selecting equalizing electrodes symmetrically arranged in the water pipe of the converter valve tower; when only one equalizing electrode is arranged on the same cross-section of the water pipe, one equalizing electrode is a measuring electrode, and the other is a reference electrode; testing the loop resistance of the measuring electrode and the loop resistance of the reference electrode respectively, removing the jumper wires of the corresponding equalizing electrodes during testing; wherein one end of the loop is the corresponding equalizing electrode, and the other end is the metal component closest to the water path; calculating the difference between the loop resistance of the measuring electrode and the loop resistance of the reference electrode, using this difference as the scale resistance and comparing it with a scale resistance threshold to determine the scaling condition of the equalizing electrode of the converter valve; the scale resistance threshold is the scale resistance that causes the leakage current between the metal pipe and the deionized water to reach the maximum allowable leakage current value.

[0006] Furthermore, the scale resistance threshold is calculated according to the following formula:

[0007]

[0008] Where R0 is the scale resistance threshold, I0 is the maximum allowable leakage current, R1 is the water resistance between the equalizing electrode and the metal pipe, and I 总 R1 is the total current, U is the voltage difference between the symmetrically arranged equalizing electrodes, and R2 is the water resistance between the symmetrically arranged equalizing electrodes.

[0009] Furthermore, if the equalizing electrode is installed in the S-shaped water pipe or the interlayer water pipe, the nearest metal component along the water path is a metal flange; if the equalizing electrode is installed in the water pipe inside the valve layer of the valve tower, the nearest metal component along the water path is a metal radiator.

[0010] Furthermore, the method also includes restoring the jumper of the corresponding equalizing electrode after the loop resistance of the measuring electrode and the loop resistance of the reference electrode have been tested.

[0011] To address the aforementioned technical problems, this invention also provides a scale detection device for the equalizing electrode of a converter valve, comprising a data acquisition module and a judgment module. The data acquisition module is used to acquire the loop resistance of the measuring electrode and the loop resistance of the reference electrode. The measuring electrode and the reference electrode are two equalizing electrodes symmetrically arranged in the water pipe of the converter valve tower when only one equalizing electrode is arranged in the same cross section. During testing, the jumpers of the corresponding equalizing electrodes are removed, one end of the data acquisition module is connected to the corresponding equalizing electrode, and the other end is connected to the metal component closest to the water path. The judgment module is used to calculate the difference between the loop resistance of the measuring electrode and the loop resistance of the reference electrode, and uses this difference as the scale resistance, comparing it with the scale resistance threshold to determine the scaling condition of the equalizing electrode of the converter valve. The scale resistance threshold is the scale resistance that causes the leakage current between the metal pipe and the deionized water to reach the maximum allowable leakage current.

[0012] Furthermore, the scale resistance threshold is calculated according to the following formula:

[0013]

[0014] Where R0 is the scale resistance threshold, I0 is the maximum allowable leakage current, R1 is the water resistance between the equalizing electrode and the metal pipe, and I 总 R1 is the total current, U is the voltage difference between the symmetrically arranged equalizing electrodes, and R2 is the water resistance between the symmetrically arranged equalizing electrodes.

[0015] The beneficial effects of the above technical solution are as follows: This invention is a pioneering invention. The arrangement of the equalizing electrodes in the converter valve tower is symmetrical. Through statistical analysis of historical inspection data, a specific rule has been obtained that "symmetrically arranged equalizing electrodes will always have scale buildup at one end and not at the other." Therefore, when only one equalizing electrode is arranged on the same cross-section of the converter valve tower water pipe, two symmetrically arranged equalizing electrodes in the converter valve tower are selected for testing. One is used as the measuring electrode, and the other as the reference electrode. Since the water circuit resistance of the measuring electrode and the reference electrode is the same, the wire resistance can be ignored. By designing a measuring circuit with one end connected to the equalizing electrode and the other end connected to the metal component closest to the water circuit, the equalizing electrode in the measuring circuit... The ionized water and metal components form a conductive circuit. The excess scale resistance is determined by measuring the difference in resistance between the circuit containing the measuring electrode and the reference electrode. The scale resistance that causes the leakage current between the metal pipe and the deionized water to reach the maximum allowable leakage current is used as the standard to evaluate the calculated scale resistance, thereby determining the scaling condition and failure status of the equalizing electrode. The measurement principle is more consistent with the function of the equalizing electrode itself. Compared with measuring thickness, the scale condition obtained by this invention is more accurate, and it does not require disassembly of the equalizing electrode, thus not damaging the structure of the equalizing electrode. This greatly improves the inspection efficiency of on-site maintenance personnel, thereby ensuring the safe operation of the converter valve. It has high application value in the fields of electrical testing and converter valve maintenance.

[0016] To address the aforementioned technical problems, this invention also provides a method for detecting scale buildup on equalizing electrodes in a converter valve. The method includes: when three equalizing electrodes are arranged on the same cross-section of the converter valve tower water pipe, the symmetrically arranged equalizing electrodes are respectively scale-forming electrodes and non-scale-forming electrodes, wherein the three scale-forming electrodes are on one cross-section, and the three non-scale-forming electrodes are on another cross-section; the three equalizing electrodes on each cross-section form a measurement loop in pairs, and the loop resistance between scale-forming electrodes and between non-scale-forming electrodes are tested respectively. During testing, the jumpers of the corresponding equalizing electrodes are removed. The loop resistance between scale-forming electrodes includes the scale resistance and water circuit resistance of the two scale-forming electrodes, and the loop resistance between non-scale-forming electrodes includes the water circuit resistance between the two non-scale-forming electrodes. Based on the loop resistance between scale-forming electrodes and the loop resistance between non-scale-forming electrodes, the scale resistance of the three scale-forming electrodes is calculated and compared with a scale resistance threshold to determine the scaling condition of the corresponding scale-forming electrodes. The scale resistance threshold is the scale resistance that causes the leakage current between the metal pipe and deionized water to reach the maximum allowable leakage current value.

[0017] Furthermore, the scale resistance is calculated according to the following formula:

[0018]

[0019] Among them, R 垢1 R is the scale resistance of the first scaling electrode. 垢2 R is the scale resistance of the second scaling electrode. 垢3 R is the scale resistance of the third scaling electrode. 结垢A R is the loop resistance between the first and second scaling electrodes. 结垢B R is the circuit resistance between the second and third scaling electrodes. 结垢C R is the loop resistance between the first and third scaling electrodes. 不结垢A R is the loop resistance between the first non-scaling electrode and the second non-scaling and scaling electrode. 不结垢B R is the loop resistance between the second and third non-scaling electrodes. 不结垢C The circuit resistance is between the first non-scaling electrode and the third non-scaling and scaling electrode.

[0020] To address the aforementioned technical problems, this invention also provides a scale detection device for equalizing electrodes in a converter valve, comprising a data acquisition module and a judgment module. The data acquisition module is used to acquire the loop resistance between scaled electrodes and the loop resistance between non-scaled electrodes. The loop resistance between scaled electrodes includes the scale resistance and water circuit resistance of the two scaled electrodes, and the loop resistance between non-scaled electrodes includes the water circuit resistance between the two non-scaled electrodes. Scaled electrodes and non-scaled electrodes refer to equalizing electrodes symmetrically arranged in the converter valve tower. During testing, the jumpers of the corresponding equalizing electrodes are removed. When three equalizing electrodes are arranged on the same cross-section of the converter valve tower water pipe, the three scaled electrodes are on one cross-section, and the three non-scaled electrodes are on another cross-section. The three equalizing electrodes on each cross-section form a measurement loop in pairs, and the data acquisition module is connected to each measurement loop. The judgment module is used to calculate the scale resistance of the three scaled electrodes based on the loop resistance between scaled electrodes and the loop resistance between non-scaled electrodes, and compare it with the scale resistance threshold to determine the scaling status of the corresponding scaled electrodes. The scale resistance threshold is the scale resistance that causes the leakage current between the metal pipe and deionized water to reach the maximum allowable leakage current.

[0021] Furthermore, the scale resistance is calculated according to the following formula:

[0022]

[0023] Among them, R 垢1 R is the scale resistance of the first scaling electrode. 垢2 R is the scale resistance of the second scaling electrode. 垢3 R is the scale resistance of the third scaling electrode. 结垢A R is the loop resistance between the first and second scaling electrodes. 结垢B R is the circuit resistance between the second and third scaling electrodes. 结垢C R is the loop resistance between the first and third scaling electrodes. 不结垢A R is the loop resistance between the first non-scaling electrode and the second non-scaling and scaling electrode. 不结垢B R is the loop resistance between the second and third non-scaling electrodes. 不结垢C The circuit resistance is between the first non-scaling electrode and the third non-scaling and scaling electrode.

[0024] The beneficial effects of the above technical solution are as follows: This invention is a pioneering invention. The arrangement of the equalizing electrodes in the converter valve tower is symmetrical. Through statistical analysis of historical inspection data, the specific rule is obtained that "symmetrically arranged equalizing electrodes will always have scale buildup at one end and no scale buildup at the other end". Therefore, equalizing electrodes arranged in one cross section of the water pipe will have scale buildup, while equalizing electrodes arranged in another cross section will not have scale buildup. For the case of three equalizing electrodes arranged in one cross section, every two equalizing electrodes form a measurement circuit. Since the circuit resistance between scaled electrodes includes the scale resistance and water circuit resistance of the two scaled electrodes, and the circuit resistance between non-scaled electrodes includes the water circuit resistance between the two non-scaled electrodes, the circuit resistance between scaled electrodes includes the water circuit resistance between the two non-scaled electrodes. Therefore, by simply testing the resistance of each loop, the scale resistance of the three scaling electrodes can be calculated. The scale resistance that causes the leakage current between the metal pipe and the deionized water to reach the maximum allowable leakage current is used as the standard to evaluate the calculated scale resistance, determine the scaling condition of the equalizing electrode and whether it has failed. The measurement principle is more in line with the function of the equalizing electrode itself. Compared with measuring the thickness, the scale condition obtained by this invention is more accurate, and there is no need to disassemble the equalizing electrode, so as not to damage the structure of the equalizing electrode. This greatly improves the inspection efficiency of on-site maintenance personnel, thereby ensuring the safe operation of the converter valve. It has high application value in the fields of electrical testing and converter valve maintenance. Attached Figure Description

[0025] Figure 1 This is a flowchart of the scale layer detection process for the equalizing electrode of the converter valve in Embodiment 1 of the present invention.

[0026] Figure 2 This is a model diagram of the leakage current absorption by the equalizing electrode in Embodiment 1 of the method of the present invention;

[0027] Figure 3 This is the wiring diagram of the equalizing electrode-metal water pipe flange test circuit in Embodiment 1 of the method of the present invention;

[0028] Figure 4 This is the wiring diagram of the equalizing electrode-heat sink test circuit in Embodiment 1 of the method of the present invention;

[0029] Figure 5 This is the wiring diagram of the equalizing electrode test circuit in Embodiment 2 of the present invention. Detailed Implementation

[0030] To make the objectives, technical solutions, and advantages of the present invention clearer, the specific embodiments of the present invention will be further described below with reference to the accompanying drawings.

[0031] This invention utilizes the symmetrical arrangement of pressure equalizing electrodes in the valve tower and obtains the rule that "symmetrically arranged pressure equalizing electrodes will have scale buildup at one end and no scale buildup at the other end" through statistical analysis of historical inspection data. The symmetrically arranged pressure equalizing electrodes in the converter valve tower are then inspected, and the scale resistance of the scaled electrode is determined using the difference method. Based on the scale resistance, the scale condition of the pressure equalizing electrode is determined.

[0032] Method Implementation Method 1

[0033] The present invention provides a method for detecting scale buildup on the equalizing electrode of a converter valve, such as... Figure 1 As shown, it includes the following steps:

[0034] 1. Establish an evaluation index R0 for the scale resistance of the equalizing electrode.

[0035] The purpose of averaging electrodes is to suppress leakage current flowing through different metal components in the water circuit. Therefore, this invention uses the scale resistance that causes the leakage current between the metal pipe and deionized water to reach the maximum allowable leakage current as the scale resistance threshold. The scale resistance threshold R0 is used as an evaluation index to evaluate the scale resistance of the averaging electrodes obtained from the test, in order to determine whether the averaging electrodes have failed.

[0036] The model of leakage current absorption by the equalizing electrode is as follows: Figure 2 As shown, the maximum leakage current flowing through the metal water pipe joint (i.e., the leakage current between the metal pipe and deionized water, and the current flowing through the water circuit resistance between the equalizing electrode and the metal pipe in the model) depends on the scale resistance and the water circuit resistance. The water circuit resistance includes the water circuit resistance R1 between the equalizing electrode and the metal pipe, and the water circuit resistance R2 between the symmetrically arranged equalizing electrodes. The maximum allowable leakage current in the converter valve manufacturer's design is I0. Taking the equalizing electrode installed on the distribution and collection pipes to suppress the leakage current flowing through the metal water pipe joint in the water circuit as an example, I0 is the maximum allowable leakage current flowing through the flange in the converter valve manufacturer's design; the current flowing through the metal flange should be less than I0. Based on the leakage current absorption model of the equalizing electrode, the scale resistance threshold is calculated using the following formula:

[0037]

[0038] Among them, I 总 U is the total current, and U is the voltage difference between the symmetrically arranged equalizing electrodes.

[0039] The water resistance R1 between the equalizing electrode and the metal pipe, and the water resistance R2 between the equalizing electrodes, are calculated using the following formulas:

[0040]

[0041] Where R is the calculated water circuit resistance (the water circuit resistance between the equalizing electrode and the metal pipe, or the water circuit resistance between the equalizing electrodes), l is the length of the water pipe, s is the cross-sectional area of ​​the water circuit, ρ is the resistivity of deionized water, and σ is the conductivity of deionized water, which is generally taken as 0.5 μS / cm.

[0042] 2. Select the measurement circuit corresponding to the equalizing electrode.

[0043] During measurement, symmetrically arranged equalizing electrodes are selected in the water pipes of the converter valve tower. When only one equalizing electrode is arranged on the same cross-section of the water pipe, one equalizing electrode is the measuring electrode, and the other equalizing electrode is the reference electrode. A conductive loop must be formed when measuring the scale resistance of the equalizing electrodes. One end of the loop is the corresponding equalizing electrode, and the other end is the nearest metal component along the water path.

[0044] like Figure 3 As shown, if the equalizing electrode is installed in the S-shaped water pipe or the interlayer water pipe, the nearest metal component along the waterway is the metal flange. For example... Figure 4 As shown, if the equalizing electrode is installed in the water pipe inside the valve layer of the valve tower, the metal component closest to it along the water path is a metal radiator (such as an aluminum alloy radiator).

[0045] 3. Determine the measuring electrode and the reference electrode.

[0046] Based on years of maintenance statistics, the structural pattern of the equalizing electrode is that "scale will form on the electrode surface where leakage current flows from the equalizing electrode to the deionized water, and vice versa." Therefore, according to this pattern, the electrode where leakage current flows from the equalizing electrode to the deionized water is designated as the measuring electrode, i.e., the measuring electrode is the scaling electrode, and the reference electrode is the non-scaling electrode. The corresponding positions of the measuring electrode and the reference electrode in the converter valve tower are shown in Table 1.

[0047] Table 1

[0048] Serial Number Measuring electrode position Reference electrode position 1 2-S pipe - valve hall ceiling side Shielded side of pole 2-S tube-valve tower top 2 Pole 1-S pipe-valve tower top shield side Pole 1-S pipe-valve hall ceiling side 3 Rectifier Station - Interlayer Water Pipe - Valve Module Cathode Rectifier Station - Interlayer Water Pipe - Valve Module Anode 4 Inverter station - interlayer water pipe - valve module anode Inverter station - interlayer water pipe - valve module cathode 5 Rectifier Station - In-Layer Water Pipes - Valve Module Cathode Rectifier Station - In-Layer Water Pipes - Valve Module Anode 6 Inverter station - In-layer water pipe - Valve module anode Inverter station - In-layer water pipe - Valve module cathode

[0049] 4. Test the loop resistance of the measuring electrode and the loop resistance of the reference electrode respectively.

[0050] During testing, the jumper wires of the corresponding equalizing electrodes need to be removed, and the tester connected to both ends of the circuit. After testing, the jumper wires must be restored, and a multimeter used to measure the continuity from the equalizing electrodes to the metal components (such as steel beams) connected by the jumper wires. An insulation resistance tester can be used; the range of the tester should be selected based on the resistance and current of the equalizing electrode circuit. For example, an insulation resistance tester with a 500V range can be used to measure the circuit resistance.

[0051] Specifically, when testing the loop resistance of the measuring electrode, remove the jumper wire of the measuring electrode and connect the tester to both ends of the measuring electrode loop. One end of the measuring electrode loop is the measuring electrode, and the other end is the metal component closest to the water path. When testing the loop resistance of the reference electrode, remove the jumper wire of the reference electrode and connect the tester to both ends of the reference electrode loop. One end of the reference electrode loop is the reference electrode, and the other end is the metal component closest to the water path.

[0052] 5. Calculate the difference between the loop resistance of the measuring electrode and the loop resistance of the reference electrode. Use this difference as the scale resistance of the equalizing electrode and compare it with the scale resistance threshold to determine the scaling condition of the equalizing electrode of the converter valve.

[0053] In a converter valve tower, the symmetrically arranged equalizing electrodes at both ends will inevitably have scale buildup at one end and remain scale-free at the other. The loop resistance of the scaled electrode includes scale resistance, water circuit resistance, and wire resistance. The loop resistance of the non-scaled electrode includes water circuit resistance and wire resistance, with the wire resistance being negligible. Since the water circuit resistances of both the scaled and non-scaled electrodes are the same, the equalizing electrode with the larger loop resistance is the scaled equalizing electrode. The difference between the loop resistance of the measuring electrode and the reference electrode is the scale resistance of the scaled equalizing electrode. When the measuring electrode refers to the electrode from which leakage current flows from the equalizing electrode to deionized water, scale will form on the surface of the measuring electrode, while the reference electrode will not. The loop resistance of the measuring electrode includes scale resistance, water circuit resistance, and wire resistance, while the loop resistance of the reference electrode includes water circuit resistance and wire resistance. The difference between the loop resistance of the measuring electrode and the loop resistance of the reference electrode is the scale resistance of the measuring electrode. In other words:

[0054]

[0055] Among them, R 结垢 To test the loop resistance of the obtained scaled electrode, R 不结垢 To test the loop resistance of the obtained non-scaling electrode, R 水 R is the resistance of the water circuit. 垢0 This refers to the scale resistance. If the scale resistance is greater than the scale resistance threshold, it indicates that the equalizing electrode has failed and needs to be descaled. If the scale resistance is greater than 0 and less than or equal to the scale resistance threshold, it indicates that the equalizing electrode has minimal scale buildup, and descaling can be determined based on requirements. If the scale resistance is 0, the surface equalizing electrode has no scale buildup.

[0056] Device Implementation Method 1

[0057] The present invention provides a device for detecting scale on the equalizing electrode of a converter valve, comprising a data acquisition module and a judgment module.

[0058] The data acquisition module is used to collect the loop resistance of the measuring electrode and the loop resistance of the reference electrode. The reference electrode and measuring electrode are two symmetrically arranged pressure-equalizing electrodes in the converter valve tower water pipe when only one pressure-equalizing electrode is arranged on the same cross-section. Through years of maintenance statistics, the structural pattern of the pressure-equalizing electrodes is that "scale will form on the electrode surface where leakage current flows from the pressure-equalizing electrode to the deionized water, and vice versa." Therefore, based on this pattern, the scaled electrode where leakage current flows from the pressure-equalizing electrode to the deionized water is used as the measuring electrode, and the corresponding non-scaling electrode is used as the reference electrode.

[0059] When collecting the loop resistance of the measuring electrode and the reference electrode, disconnect the jumper wires of the corresponding equalizing electrodes. Connect one end of the data acquisition module to the corresponding equalizing electrode and the other end to the nearest metal component along the water path. If the equalizing electrode is located in an S-shaped water pipe or an interlayer water pipe, the nearest metal component along the water path is a metal flange; if the equalizing electrode is located in a water pipe within the valve layer of the valve tower, the nearest metal component along the water path is a metal radiator.

[0060] The determination module calculates the difference between the loop resistance of the measuring electrode and the loop resistance of the reference electrode. This difference is used as the scale resistance and compared with the scale resistance threshold to determine the scale buildup on the pressure equalization electrode of the converter valve. The scale resistance threshold is the scale resistance required to achieve the maximum allowable leakage current between the metal pipe and the deionized water. The calculation formula is as follows:

[0061]

[0062] Where R0 is the scale resistance threshold, I0 is the maximum allowable leakage current, R1 is the water resistance between the equalizing electrode and the metal pipe, and I 总 Let U be the total current, U be the voltage difference between the symmetrically arranged equalizing electrodes, and R2 be the water resistance between the symmetrically arranged equalizing electrodes. The water resistance R1 between the equalizing electrodes and the metal pipe, and the water resistance R2 between the symmetrically arranged equalizing electrodes, are calculated using the following formulas:

[0063]

[0064] Where R is the calculated water circuit resistance, l is the length of the water pipe, s is the cross-sectional area of ​​the water circuit, ρ is the resistivity of deionized water, and σ is the conductivity of deionized water, which is generally taken as 0.5 μS / cm.

[0065] Method Implementation Method Two

[0066] The present invention provides a method for detecting scale on the equalizing electrode of a converter valve, comprising the following steps:

[0067] S1: When three equalizing electrodes are arranged on the same cross section of the water pipe of the converter valve tower, the symmetrically arranged equalizing electrodes are scaling electrodes and non-scaling electrodes, with the three scaling electrodes on one cross section and the three non-scaling electrodes on another cross section.

[0068] Based on years of maintenance statistics, the structural pattern of the equalizing electrode is that "scale will form on the electrode surface where the leakage current flows from the equalizing electrode to the deionized water, and vice versa." Therefore, according to this pattern, the three electrodes on the cross section where the leakage current flows from the equalizing electrode to the deionized water are scale-forming electrodes, while the three equalizing electrodes on the other cross section that are symmetrically arranged are non-scale-forming electrodes.

[0069] During measurement, symmetrically arranged equalizing electrodes are selected in the converter valve tower. Since a conductive circuit must be formed when measuring the scale resistance of the equalizing electrodes, when three equalizing electrodes are arranged on the same cross section of the converter valve tower water pipe, the three equalizing electrodes on each cross section form a measurement circuit in pairs.

[0070] S2: Test the loop resistance between scaled electrodes and the loop resistance between non-scaled electrodes respectively. During the test, remove the jumper wires of the corresponding equalizing electrodes respectively. After the test is completed, restore the jumper wires of the corresponding equalizing electrodes.

[0071] The loop resistance between scaling electrodes includes the scale resistance of the two scaling electrodes and the water circuit resistance, while the loop resistance between non-scaling electrodes includes the water circuit resistance between the two non-scaling electrodes. For example... Figure 5 As shown, taking the cross-section where the scaling electrode is located as an example, the three scaling electrodes form three measurement loops in pairs: first scaling electrode-second scaling electrode, second scaling electrode-third scaling electrode, and first scaling electrode-third scaling electrode. The loop resistance between the scaling electrodes in each of the three measurement loops is measured using an insulation resistance meter. The loop resistance between the scaling electrodes satisfies the following formula:

[0072] R 结垢A =R 垢1 +R 垢2 +R 水1

[0073] R 结垢B =R 垢2 +R 垢3 +R 水2

[0074] R 结垢C =R 垢1 +R 垢3 +R 水2

[0075] Among them, R 垢1 R is the scale resistance of the first scaling electrode. 垢2 R is the scale resistance of the second scaling electrode. 垢3R is the scale resistance of the third scaling electrode. 结垢A R is the loop resistance between the first and second scaling electrodes. 结垢B R is the circuit resistance between the second and third scaling electrodes. 结垢C R is the loop resistance between the first and third scaling electrodes. 水1 R 水2 R 水3 These are the water circuit resistances between the first and second scaling electrodes, the water circuit resistances between the second and third scaling electrodes, and the water circuit resistances between the first and third scaling electrodes, respectively. The loop resistances between the three non-scaling electrodes are obtained using an insulation resistance meter. The loop resistances between the non-scaling electrodes satisfy the following formula:

[0076] R 不结垢A =R 水1

[0077] R 不结垢B =R 水2

[0078] R 不结垢C =R 水2

[0079] Among them, R 不结垢A R is the loop resistance between the first non-scaling electrode and the second non-scaling and scaling electrode. 不结垢B R is the loop resistance between the second and third non-scaling electrodes. 不结垢C The circuit resistance is between the first non-scaling electrode and the third non-scaling and scaling electrode. The first scaling resistor and the first non-scaling resistor are arranged symmetrically, the second scaling resistor and the second non-scaling resistor are arranged symmetrically, and the third scaling resistor and the third non-scaling resistor are arranged symmetrically.

[0080] S3: Calculate the scale resistance of the three scaled electrodes based on the loop resistance between scaled electrodes and the loop resistance between non-scaled electrodes, and compare it with the scale resistance threshold to determine the scaling status of the corresponding scaled electrodes.

[0081] The scale resistance is calculated using the following formula:

[0082]

[0083] The scale resistance threshold is the scale resistance required to cause the leakage current between the metal pipe and deionized water to reach the maximum allowable leakage current. The calculation method for the scale resistance threshold has been described in detail in one embodiment of the method, and will not be repeated here.

[0084] If the scale resistance is greater than the scale resistance threshold, it indicates that the equalizing electrode has failed and needs to be descaled. If the scale resistance is greater than 0 and less than or equal to the scale resistance threshold, it indicates that the equalizing electrode has minimal scale buildup, and descaling can be determined based on requirements. If the scale resistance is 0, the surface equalizing electrode has no scale buildup.

[0085] Device Implementation Method 2

[0086] This invention discloses a scale detection device for equalizing electrodes in a converter valve, comprising a data acquisition module and a judgment module. The data acquisition module is used to collect the loop resistance between scaled electrodes and the loop resistance between non-scaled electrodes. The loop resistance between scaled electrodes includes the scale resistance and water circuit resistance of the two scaled electrodes, while the loop resistance between non-scaled electrodes includes the water circuit resistance between the two non-scaled electrodes. Scaled and non-scaled electrodes refer to equalizing electrodes symmetrically arranged in the converter valve tower. During testing, the jumpers of the corresponding equalizing electrodes are removed. When three equalizing electrodes are arranged on the same cross-section of the converter valve tower water pipe, the three scaled electrodes are on one cross-section, and the three non-scaled electrodes are on another cross-section. The three equalizing electrodes on each cross-section form a measurement loop in pairs. The data acquisition module is connected to each measurement loop to collect the loop resistance between each scaled electrode and the loop resistance between each non-scaled electrode.

[0087] The determination module is used to calculate the scale resistance of the three scaled electrodes based on the loop resistance between scaled electrodes and the loop resistance between non-scaled electrodes, and compare it with the scale resistance threshold to determine the scaling status of the corresponding scaled electrodes.

[0088] The calculation process for scale resistance has been detailed in Implementation Method 2 and will not be repeated here. If the scale resistance is greater than the scale resistance threshold, it indicates that the equalizing electrode has failed and needs to be descaled. If the scale resistance is greater than 0 and less than or equal to the scale resistance threshold, it indicates that the equalizing electrode has minimal scale buildup, and descaling can be determined based on requirements. If the scale resistance is 0, the surface equalizing electrode has no scale buildup. The scale resistance threshold is the scale resistance required to achieve the maximum allowable leakage current between the metal pipe and the deionized water.

[0089] This invention utilizes the symmetrical arrangement of equalizing electrodes in converter valve towers and, through statistical analysis of historical inspection data, establishes the rule that "symmetrically arranged equalizing electrodes will always have scale buildup at one end and remain scale-free at the other." By measuring the resistance of the circuit containing the symmetrically arranged equalizing electrodes in the converter valve tower, the circuit resistances of the scaled and non-scaled electrodes are obtained. Based on these circuit resistances, the scale resistance of the scaled electrode is calculated, eliminating the need to consider the influence of changes in the conductivity of deionized water on the measurement, thus improving the accuracy of scale resistance measurement. An evaluation index for scale resistance, based on a model of leakage current absorption by the equalizing electrode, is used to assess the actual scaling condition of the measured scale resistance. When the measured scale resistance exceeds the evaluation index, it indicates that the equalizing electrode has failed, which is more consistent with the working principle of the equalizing electrode, resulting in higher evaluation accuracy. Furthermore, it eliminates the need to disassemble the equalizing electrode, greatly accelerating the efficiency of on-site maintenance personnel in inspecting the scale layer on the equalizing electrode, thereby ensuring the safe operation of the converter valve. This invention has high application value in electrical testing and converter valve maintenance.

Claims

1. A method for detecting scale buildup on the equalizing electrode of a converter valve, characterized in that, include: A pressure equalization electrode is selected to be symmetrically arranged in the water pipe of the converter valve tower. When only one pressure equalization electrode is arranged in the same cross section of the water pipe of the converter valve tower, one pressure equalization electrode is the measuring electrode and the other pressure equalization electrode is the reference electrode. Test the loop resistance of the measuring electrode and the loop resistance of the reference electrode separately. During the test, remove the jumper wires of the corresponding equalizing electrodes. One end of the loop is the corresponding equalizing electrode, and the other end is the metal component closest to the water path. Calculate the difference between the loop resistance of the measuring electrode and the loop resistance of the reference electrode, use this difference as the scale resistance and compare it with the scale resistance threshold to determine the scaling status of the pressure equalization electrode of the converter valve; the scale resistance threshold is the scale resistance that makes the leakage current between the metal pipe and the deionized water reach the maximum allowable leakage current.

2. The method for detecting scale on the equalizing electrode of a converter valve according to claim 1, characterized in that, The scale resistance threshold is calculated according to the following formula: Where R0 is the scale resistance threshold, I0 is the maximum allowable leakage current, and R1 is the water resistance between the equalizing electrode and the metal pipe. R1 is the total current, U is the voltage difference between the symmetrically arranged equalizing electrodes, and R2 is the water resistance between the symmetrically arranged equalizing electrodes.

3. The method for detecting scale on the equalizing electrode of a converter valve according to claim 1 or 2, characterized in that, If the equalizing electrode is installed in the S-shaped water pipe or the interlayer water pipe, the nearest metal component along the water path is the metal flange; if the equalizing electrode is installed in the water pipe inside the valve layer of the valve tower, the nearest metal component along the water path is the metal radiator.

4. The method for detecting scale on the equalizing electrode of a converter valve according to claim 1 or 2, characterized in that, The method also includes restoring the jumper wires of the corresponding voltage equalization electrodes after the loop resistance of the measuring electrode and the loop resistance of the reference electrode have been tested.

5. A method for detecting scale on the equalizing electrode of a converter valve, characterized in that, include: When three equalizing electrodes are arranged on the same cross section of the water pipe of the converter valve tower, the symmetrically arranged equalizing electrodes are respectively scaling electrodes and non-scaling electrodes. Among them, the three scaling electrodes are on one cross section, and the three non-scaling electrodes are on one cross section. The three equalizing electrodes of each section form a measurement circuit in pairs to test the circuit resistance between scaled electrodes and the circuit resistance between non-scaled electrodes. During the test, the jumper wires of the corresponding equalizing electrodes are removed. The circuit resistance between scaled electrodes includes the scale resistance and water circuit resistance of the two scaled electrodes, and the circuit resistance between non-scaled electrodes includes the water circuit resistance between the two non-scaled electrodes. The scale resistance of the three scaled electrodes is calculated based on the loop resistance between scaled electrodes and the loop resistance between non-scaled electrodes, and compared with the scale resistance threshold to determine the scaling status of the corresponding scaled electrodes; the scale resistance threshold is the scale resistance that makes the leakage current between the metal pipe and the deionized water reach the maximum allowable leakage current.

6. The method for detecting scale on the equalizing electrode of a converter valve according to claim 5, characterized in that, The resistance of the scale layer is calculated according to the following formula: in, The scale resistance of the first scaling electrode. The scale resistance of the second scaling electrode. The scale resistance of the third scaling electrode. The circuit resistance between the first and second scaling electrodes is [value missing]. The circuit resistance between the second and third scaling electrodes. The circuit resistance between the first and third scaling electrodes is [value missing]. The circuit resistance between the first and second non-scaling electrodes is [value missing]. The circuit resistance between the second and third non-scaling electrodes is [value missing]. The circuit resistance is between the first non-scaling electrode and the third non-scaling electrode.

7. A device for detecting scale buildup on a pressure equalization electrode of a converter valve, characterized in that, It includes a data acquisition module and a judgment module. The data acquisition module is used to collect the loop resistance of the measuring electrode and the loop resistance of the reference electrode. The measuring electrode and the reference electrode are two symmetrically arranged pressure equalizing electrodes in the water pipe of the converter valve tower when only one pressure equalizing electrode is arranged in the same cross section. During the test, the jumper wires of the corresponding pressure equalizing electrodes are removed, one end of the data acquisition module is connected to the corresponding pressure equalizing electrode, and the other end is connected to the metal component closest to the water path. The judgment module is used to calculate the difference between the loop resistance of the measuring electrode and the loop resistance of the reference electrode, and uses this difference as the scale resistance and compares it with the scale resistance threshold to determine the scaling status of the pressure equalizing electrode of the converter valve. The scale resistance threshold is the scale resistance that makes the leakage current between the metal pipe and the deionized water reach the maximum allowable leakage current.

8. The device for detecting scale on the equalizing electrode of a converter valve according to claim 7, characterized in that, The scale resistance threshold is calculated according to the following formula: Where R0 is the scale resistance threshold, I0 is the maximum allowable leakage current, and R1 is the water resistance between the equalizing electrode and the metal pipe. R1 is the total current, U is the voltage difference between the symmetrically arranged equalizing electrodes, and R2 is the water resistance between the symmetrically arranged equalizing electrodes.

9. A device for detecting scale layer on the equalizing electrode of a converter valve, characterized in that, The system includes a data acquisition module and a judgment module. The data acquisition module collects the loop resistance between scaling electrodes and the loop resistance between non-scaling electrodes. The loop resistance between scaling electrodes includes the scale resistance and water circuit resistance of the two scaling electrodes, while the loop resistance between non-scaling electrodes includes the water circuit resistance between the two non-scaling electrodes. Scaling electrodes and non-scaling electrodes refer to the symmetrically arranged pressure equalizing electrodes in the converter valve tower. During testing, the jumpers of the corresponding pressure equalizing electrodes are removed. When three pressure equalizing electrodes are arranged on the same cross section of the converter valve tower water pipe, the three scaling electrodes are on one cross section, and the three non-scaling electrodes are on another cross section. The three pressure equalizing electrodes on each cross section form a measurement loop in pairs, and the data acquisition module is connected to each measurement loop. The judgment module calculates the scale resistance of the three scaling electrodes based on the loop resistance between scaling electrodes and the loop resistance between non-scaling electrodes, and compares it with the scale resistance threshold to determine the scaling status of the corresponding scaling electrodes. The scale resistance threshold is the scale resistance that causes the leakage current between the metal pipe and the deionized water to reach the maximum allowable leakage current.

10. The device for detecting scale on the equalizing electrode of a converter valve according to claim 9, characterized in that, The resistance of the scale layer is calculated according to the following formula: in, The scale resistance of the first scaling electrode. The scale resistance of the second scaling electrode. The scale resistance of the third scaling electrode. The circuit resistance between the first and second scaling electrodes is [value missing]. The circuit resistance between the second and third scaling electrodes. The circuit resistance between the first and third scaling electrodes is [value missing]. The circuit resistance between the first and second non-scaling electrodes is [value missing]. The circuit resistance between the second and third non-scaling electrodes is [value missing]. The circuit resistance is between the first non-scaling electrode and the third non-scaling electrode.

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