Fault analysis method and system for direct current converter valve

Abstract

The invention provides a fault analysis method and system for a direct current converter valve, and the method comprises the steps: applying a test voltage to the direct current converter valve through a voltage generator, and collecting the voltage of each potential sampling point in the direct current converter valve; and performing fault analysis on the direct current converter valve based on the voltage of each potential sampling point. According to the method, the potential distribution testing electrical model of each type of testing voltage is established, a potential distribution theoretical calculation method and potential distribution abnormity reason analysis are provided, and targeted testing and analysis are realized, the correctness of converter valve design is checked, and the circuit abnormity reason is analyzed.

Description

Technical Field

[0001] The present invention relates to the field of power transmission technology, and in particular to a fault analysis method and system for a DC converter valve. Background Art

[0002] The converter valve is the core equipment for realizing AC / DC power conversion in DC power transmission projects. It plays an important role in the power transmission and transformation process. It is suitable for long-distance power transmission scenarios and can realize asynchronous power grid interconnection. Usually, the converter valve ensures its insulation reliability in high-altitude areas by increasing the number of series connections, but a large number of series connections will increase the degree of uneven potential distribution inside the converter valve. With the increasing application of converter valves in high-altitude areas, the problem of single potential distribution measurement implementation method and insufficient intelligent analysis and processing of measurement data has gradually become prominent. Summary of the invention

[0003] In order to solve the problems in the prior art that the potential measurement implementation method of a DC converter valve is single and the analysis and processing of measurement data is not intelligent enough, the present invention provides a fault analysis method and system for a DC converter valve.

[0004] The technical solution provided by the present invention is:

[0005] A voltage generator is used to apply a test voltage to the DC converter valve, and the voltage of each potential sampling point in the DC converter valve is collected;

[0006] Performing fault analysis on the DC converter valve based on the voltages at each potential sampling point;

[0007] The potential sampling point is any one level of thyristor in the valve module of the DC converter valve, and the test voltage is a DC voltage, an AC voltage or an impulse voltage.

[0008] Preferably, when the test voltage is a DC voltage, the fault analysis of the DC converter valve based on the voltage data of each potential sampling point includes:

[0009] If the waveform ripple coefficients of the test voltage and the voltages at each potential sampling point are the same, the DC converter valve is in a normal state; otherwise, the DC converter valve is in an abnormal state.

[0010] Preferably, when the test voltage is a DC voltage, the fault analysis of the DC converter valve based on the voltage data of each potential sampling point includes:

[0011] When the sampling voltage at the potential sampling point i is 0 and the difference between the sampling voltages at the other potential sampling points and their corresponding theoretical sampling voltages does not exceed the threshold, the thyristor at the potential sampling point i has a short circuit fault;

[0012] When the difference between the sampling voltage at the potential sampling point i and its corresponding theoretical sampling voltage exceeds the threshold and the differences between the sampling voltages at the remaining potential sampling points and their corresponding theoretical sampling voltages do not exceed the threshold, the voltage-equalizing circuit element corresponding to the thyristor at the potential sampling point i is faulty;

[0013] When the differences between the sampling voltages of all potential sampling points in the valve module to which the potential sampling point i belongs and their corresponding theoretical sampling voltages exceed the threshold, there is a water circuit installation or internal cooling medium failure in the valve module to which the potential sampling point i belongs.

[0014] Preferably, the theoretical voltage at the voltage collection point i is determined by the following formula:

[0015] U i =U×(N i ×R dc / / R w-i ) / {(∑N j ×R dc / / R wj )×N i}

[0016] Among them, U i is the theoretical voltage at the voltage collection point i, U is the test voltage, n is the total number of thyristors in series in the test converter valve, i,j∈[1,m], m is the number of valve modules in the converter valve, ∑N j =n,N i is the number of thyristors in the valve module to which the voltage acquisition point i belongs, N j is the number of thyristors in the valve module to which the voltage acquisition point j belongs, R dc is the resistance value of the voltage-equalizing loop, R wj is the equivalent water circuit resistance value of the valve module in parallel to the voltage collection point j, R w-i is the equivalent loop resistance connected in parallel with the valve module at the potential sampling point i.

[0017] Preferably, when the test voltage is an AC voltage, the fault analysis of the DC converter valve based on the voltage data of each potential sampling point includes:

[0018] If the output waveforms of the test voltage and the voltages at each potential sampling point are consistent and the amplitude difference between the test voltage and the voltages at each potential sampling point does not exceed a threshold, the DC converter valve is in a normal state; otherwise, the DC converter valve is in an abnormal state.

[0019] Preferably, when the test voltage is an AC voltage, the fault analysis of the DC converter valve based on the voltage data of each potential sampling point includes:

[0020] When the sampling voltage at the potential sampling point i is 0 and the difference between the sampling voltages at the other potential sampling points and their corresponding theoretical sampling voltages does not exceed the threshold, the thyristor at the potential sampling point i has a short circuit fault;

[0021] When the difference between the sampling voltage at the potential sampling point i and the corresponding theoretical sampling voltage exceeds the threshold or when the waveform phase deviation between the sampling voltage at the potential sampling point i and the corresponding theoretical sampling voltage exceeds the threshold, the damping circuit element corresponding to the thyristor at the potential sampling point i is faulty;

[0022] When the sampling voltages of all potential sampling points in the valve module to which the potential sampling point i belongs are higher than their corresponding theoretical sampling voltages and the difference between them exceeds the threshold, there is a multi-stage thyristor short circuit or wiring fault in the valve module to which the potential sampling point belongs.

[0023] Preferably, the theoretical voltage at the voltage collection point i is determined by the following formula:

[0024] U i =U / n;

[0025] Among them, U i is the theoretical voltage at the voltage collection point i, U is the test voltage, and n is the total number of thyristors in series for the test converter valve.

[0026] Preferably, when the test voltage is an impulse voltage, the fault analysis of the DC converter valve based on the voltage data of each potential sampling point includes:

[0027] If the time difference between the wave head and the wave tail of the voltage waveform at each potential sampling point does not exceed the threshold and satisfies U i ×x+U 电抗器i =U j ×y+U 电抗器j , the DC converter valve is in a normal state, otherwise, the DC converter valve is in an abnormal state;

[0028] Among them, U i is the theoretical voltage at the voltage collection point i, U j is the theoretical voltage at voltage collection point j, U 电抗器i is the voltage of the valve module reactor at the potential sampling point i, U 电抗器j is the voltage of the inductor of the valve module at the potential sampling point j, x is the number of thyristors in series of the valve module at the potential sampling point i, and y is the number of thyristors in series of the valve module at the potential sampling point j.

[0029] Preferably, when the test voltage is an impulse voltage, the fault analysis of the DC converter valve based on the voltage data of each potential sampling point includes:

[0030] When the sampling voltage at the potential sampling point i is 0, there is a short-circuit fault in the thyristor at the potential sampling point i;

[0031] When the sampling voltage at the potential sampling point i is the same as the corresponding theoretical sampling voltage waveform parameter, the negative deviation of the voltage of the reactor of the valve module at the potential sampling point i exceeds the threshold, and the product of the voltage of the reactor of the valve module at the potential sampling point i plus the number of series thyristors of the valve module at the potential sampling point i and the sampling voltage at the potential sampling point i is equal to the set fraction of the test voltage, the reactor in the valve module at the potential sampling point i is faulty;

[0032] When the sampling voltage at the potential sampling point i is the same as the corresponding theoretical sampling voltage waveform parameter, and the reactor voltage of the valve module to which the potential sampling point i belongs is greater than the set fraction of the test voltage, the thyristor at the non-potential sampling point i of the valve module to which the potential sampling point i belongs is faulty;

[0033] When the waveform parameters of the sampled voltage at the potential acquisition point i differ from the waveform parameters of the test voltage by more than a threshold, the converter valve structure or the test circuit equipment layout fails;

[0034] The waveform parameters include wave head time and wave tail time.

[0035] Based on the same inventive concept, the present invention also provides a fault analysis system for a DC converter valve, comprising: a collection module and a fault analysis module;

[0036] The acquisition module is used to apply a test voltage to the DC converter valve using a voltage generator, and to collect voltages at various potential sampling points in the DC converter valve;

[0037] The fault analysis module is used to perform fault analysis on the DC converter valve based on the voltages at each potential sampling point;

[0038] The potential sampling point is any one level of thyristor in the valve module of the DC converter valve, and the test voltage is a DC voltage, an AC voltage or an impulse voltage.

[0039] Preferably, when the test voltage is a DC voltage, the fault analysis module is used to:

[0040] If the waveform ripple coefficients of the test voltage and the voltages at each potential sampling point are the same, the DC converter valve is in a normal state; otherwise, the DC converter valve is in an abnormal state.

[0041] Preferably, when the test voltage is a DC voltage, the fault analysis module is used to:

[0042] When the sampling voltage at the potential sampling point i is 0 and the difference between the sampling voltages at the other potential sampling points and their corresponding theoretical sampling voltages does not exceed the threshold, the thyristor at the potential sampling point i has a short circuit fault;

[0043] When the difference between the sampling voltage at the potential sampling point i and its corresponding theoretical sampling voltage exceeds the threshold and the differences between the sampling voltages at the remaining potential sampling points and their corresponding theoretical sampling voltages do not exceed the threshold, the voltage-equalizing circuit element corresponding to the thyristor at the potential sampling point i is faulty;

[0044] When the differences between the sampling voltages of all potential sampling points in the valve module to which the potential sampling point i belongs and their corresponding theoretical sampling voltages exceed the threshold, there is a water circuit installation or internal cooling medium failure in the valve module to which the potential sampling point i belongs.

[0045] Preferably, when the test voltage is a DC voltage, the theoretical voltage at the voltage collection point i in the fault analysis module is determined by the following formula:

[0046] U i =U×(N i ×R dc / / R w-i ) / {(∑N j ×R dc / / R wj )×N i}

[0047] Among them, U i is the theoretical voltage at the voltage collection point i, U is the test voltage, n is the total number of thyristors in series in the test converter valve, i,j∈[1,m], m is the number of valve modules in the converter valve, ∑N j =n,N i is the number of thyristors in the valve module to which the voltage acquisition point i belongs, N j is the number of thyristors in the valve module to which the voltage acquisition point j belongs, R dc is the resistance value of the voltage-equalizing loop, R wj is the equivalent water circuit resistance value of the valve module in parallel to the voltage collection point j, R w-i is the equivalent loop resistance connected in parallel with the valve module at the potential sampling point i.

[0048] Preferably, when the test voltage is an AC voltage, the fault analysis module is used to:

[0049] If the output waveforms of the test voltage and the voltages at each potential sampling point are consistent and the amplitude difference between the test voltage and the voltages at each potential sampling point does not exceed a threshold, the DC converter valve is in a normal state; otherwise, the DC converter valve is in an abnormal state.

[0050] Preferably, when the test voltage is an AC voltage, the fault analysis module is used to:

[0051] When the sampling voltage at the potential sampling point i is 0 and the difference between the sampling voltages at the other potential sampling points and their corresponding theoretical sampling voltages does not exceed the threshold, the thyristor at the potential sampling point i has a short circuit fault;

[0052] When the difference between the sampling voltage at the potential sampling point i and the corresponding theoretical sampling voltage exceeds the threshold or when the waveform phase deviation between the sampling voltage at the potential sampling point i and the corresponding theoretical sampling voltage exceeds the threshold, the damping circuit element corresponding to the thyristor at the potential sampling point i is faulty;

[0053] When the sampling voltages of all potential sampling points in the valve module to which the potential sampling point i belongs are higher than their corresponding theoretical sampling voltages and the difference between them exceeds the threshold, there is a multi-stage thyristor short circuit or wiring fault in the valve module to which the potential sampling point belongs.

[0054] Preferably, when the test voltage is an AC voltage, the theoretical voltage at the voltage collection point i in the fault analysis module is determined by the following formula:

[0055] U i =U / n;

[0056] Among them, U i is the theoretical voltage at the voltage collection point i, U is the test voltage, and n is the total number of thyristors in series for the test converter valve.

[0057] Preferably, when the test voltage is an impulse voltage, the fault analysis module is used to:

[0058] If the time difference between the wave head and the wave tail of the voltage waveform at each potential sampling point does not exceed the threshold and satisfies U i ×x+U 电抗器i =U j ×y+U 电抗器j , the DC converter valve is in a normal state, otherwise, the DC converter valve is in an abnormal state;

[0059] Among them, U i is the theoretical voltage at the voltage collection point i, U j is the theoretical voltage at voltage collection point j, U 电抗器i is the voltage of the valve module reactor at the potential sampling point i, U 电抗器j is the voltage of the inductor of the valve module at the potential sampling point j, x is the number of thyristors in series of the valve module at the potential sampling point i, and y is the number of thyristors in series of the valve module at the potential sampling point j.

[0060] Preferably, when the test voltage is an impulse voltage, the fault analysis module is used to:

[0061] When the sampling voltage at the potential sampling point i is 0, there is a short-circuit fault in the thyristor at the potential sampling point i;

[0062] When the sampling voltage at the potential sampling point i is the same as the corresponding theoretical sampling voltage waveform parameter, the negative deviation of the voltage of the reactor of the valve module at the potential sampling point i exceeds the threshold, and the product of the voltage of the reactor of the valve module at the potential sampling point i plus the number of series thyristors of the valve module at the potential sampling point i and the sampling voltage at the potential sampling point i is equal to the set fraction of the test voltage, the reactor in the valve module at the potential sampling point i is faulty;

[0063] When the sampling voltage at the potential sampling point i is the same as the corresponding theoretical sampling voltage waveform parameter, and the reactor voltage of the valve module to which the potential sampling point i belongs is greater than the set fraction of the test voltage, the thyristor at the non-potential sampling point i of the valve module to which the potential sampling point i belongs is faulty;

[0064] When the waveform parameters of the sampled voltage at the potential acquisition point i differ from the waveform parameters of the test voltage by more than a threshold, the converter valve structure or the test circuit equipment layout fails;

[0065] The waveform parameters include wave head time and wave tail time.

[0066] Compared with the prior art, the present invention has the following beneficial effects:

[0067] The present invention provides a fault analysis method and system for a DC converter valve, which uses a voltage generator to apply a test voltage to the DC converter valve, and collects the voltages of each potential sampling point in the DC converter valve; based on the voltages of each potential sampling point, the DC converter valve is subjected to fault analysis. The present invention realizes targeted analysis of DC converter valve faults under different voltage modes by dividing different test modes according to voltage. BRIEF DESCRIPTION OF THE DRAWINGS

[0068] Figure 1 A flow chart of a fault analysis method for a DC converter valve according to the present invention;

[0069] Figure 2 It is a structural schematic diagram of a fault analysis system of a DC converter valve according to the present invention;

[0070] Figure 3 A schematic diagram of a fault analysis system for a DC converter valve according to the present invention;

[0071] Figure 4 A typical structural schematic diagram of a valve module of a fault analysis system for a DC converter valve according to the present invention;

[0072] Figure 5 An electrical diagram of an equivalent valve module in a DC potential distribution measurement mode of a DC converter valve fault analysis system of the present invention;

[0073] Figure 6 An electrical diagram of an equivalent valve module in an AC potential distribution measurement mode of a fault analysis system for a DC converter valve of the present invention;

[0074] Figure 7 This is an electrical diagram of an equivalent valve module of an impulse potential distribution measurement mode of a fault analysis system for a DC converter valve of the present invention. DETAILED DESCRIPTION

[0075] The specific implementation modes of the present invention are further described in detail below with reference to the accompanying drawings.

[0076] Example 1

[0077] The present invention provides a fault analysis method for a DC converter valve, the flow chart of which is as follows: Figure 1 As shown, Figure 2 The structural diagram of the fault analysis system is shown in Figure 1. SR represents the saturated reactor and Thy represents the thyristor, including:

[0078] S1. Apply a test voltage to the DC converter valve using a voltage generator, and collect voltages at each potential sampling point in the DC converter valve;

[0079] S2. Fault analysis of the DC converter valve based on the voltage at each potential sampling point;

[0080] The potential sampling point is any one level of thyristor in the valve module of the DC converter valve, and the test voltage is a DC voltage, an AC voltage or an impulse voltage.

[0081] Step S1 specifically includes: the data acquisition module in step S1 mainly includes three parts: a high-precision active or passive voltage sensor, an optical fiber transmission loop, and a waveform acquisition storage device. The test voltage generator is a voltage generator.

[0082] The acquisition module has two main functions: (1) Acquiring test voltage waveform data as input for subsequent potential distribution calculation and data analysis. (2) Acquiring the potential of devices at different locations inside the converter valve as input for actual measurement of potential distribution and data analysis.

[0083] The fault analysis in step S2 specifically includes: 1. Comparison and analysis between the output waveform of the voltage generator and the actual waveform collected by the high-potential voltage acquisition module, and calculation of the measurement deviation caused by the signal transmission link; 2. Comparison and analysis between the median value of the potential distribution and the voltage of each measuring point, and the unevenness of the tested potential distribution is given; 3. Comparison and analysis between the measured value of the potential distribution and the theoretical value, to determine whether the design of the converter valve is reasonable, and whether the device is installed incorrectly or damaged.

[0084] Figure 3 The following is a typical structural diagram of the valve module. Usually, the thyristor level circuit includes three parts: thyristor, voltage equalization circuit, and damping circuit. The valve module also includes a saturated reactor and a voltage equalization capacitor. The thyristor exhibits a high resistance in the blocking state, usually more than tens of MΩ; the voltage equalization circuit is connected in parallel at both ends of the thyristor, usually with a resistance of about 80 to 100 kΩ, making the voltage of each thyristor level basically the same under low frequency and DC voltage; the RC circuit includes a damping capacitor and a damping resistor. The damping capacitor capacitance is usually below 2 μF, and the damping resistor is usually 30 Ω to 50 Ω. It plays a dynamic voltage equalization role under power frequency and high-frequency impulse voltage to ensure that the voltage of each thyristor level remains balanced. Due to the heat loss generated during the operation of the converter valve, the temperature of the thyristor rises. A cooling medium is required to ensure that the thyristor temperature is within the tolerance range of the device. The equivalent resistance of the cooling medium is related to the conductivity of the medium, the length of the water path, and the diameter of the pipe. Its equivalent resistance is obtained by calculation. Usually, the equivalent resistance of the water path is more than tens of MΩ.

[0085] Before the test, select the corresponding potential distribution measurement mode according to the test voltage type. The measurement modes are divided into AC voltage potential distribution measurement mode, DC voltage potential distribution measurement mode, and impulse voltage distribution measurement mode. The measurement mode selection module contains equivalent parameter models of various types of voltage converter valves. By using different potential distribution test electrical models under different test types, the key parameters affecting the potential distribution are determined. The corresponding key parameter settings can be provided according to the type of measurement mode. The operator can input the converter valve parameters according to the prompts to complete the matching of the test mode with the actual test voltage.

[0086] The basic test process is as follows: before the experiment, high-potential voltage collectors are arranged according to the number of converter valve modules, and at the same time, high-potential voltage collectors are arranged at the measuring end of the test voltage generator to collect voltage waveforms for subsequent waveform comparison; according to the test voltage type, the corresponding test mode is selected, and the system displays the converter valve parameters that need to be entered. After the operator enters the parameters according to the prompts, the test machine data is collected and transmitted to the calculation and analysis module; the calculation and analysis module gives the potential distribution data according to the algorithm based on the potential distribution test data, and gives the cause analysis for the points where the distribution data obviously deviates from the normal range.

[0087] In the DC potential distribution measurement mode, under the action of DC voltage, the damping circuit is in an open circuit state due to the presence of capacitors and has no effect on the potential distribution; under the action of DC voltage, the saturated reactor exhibits resistance characteristics. Since its DC resistance is at the mΩ level, its effect on the potential distribution can be ignored compared to the DC equalizing resistor and the water circuit equivalent resistance. Since the resistance value of the equalizing circuit is about 100kΩ, after multiple stages are connected in series, the magnitude is close to the equivalent resistance of the cooling circuit. Therefore, the simplified DC potential distribution measurement equivalent valve module model is as follows: Figure 4 Parameter setting interface: the equivalent water circuit resistance value of each valve module, the specific series number of each valve module, and the resistance value of a single-stage equalizing circuit.

[0088] In the AC potential distribution measurement mode, under the action of AC voltage, the parallel impedance of the thyristor stage inside the valve module mainly depends on the damping capacitor parameters in the RC voltage-equalizing circuit. The voltage-equalizing resistor may have a certain impact on the result. The equivalent power frequency inductance of the saturated reactor in series is less than 1mH, and the inductive reactance value is less than 1Ω, which has no effect on the potential distribution. According to the capacitor impedance calculation formula: X c =1 / 2pifC, when the capacitance is 2μF, the capacitive reactance is basically around 1.5kΩ, and the thyristor-level parallel impedance approaches the damping circuit capacitive reactance. Taking the valve module as a unit, since the equivalent resistance of the water path is more than tens of MΩ, after being connected in parallel at both ends of the valve module, the overall impedance of the module approaches the series impedance of all the thyristor-level RC circuits and voltage-equalizing circuits in the module. Similarly, the capacitance of the voltage-equalizing capacitor is usually in the nF level, and after being connected in parallel at both ends of the valve module, the impact on the overall impedance can be basically ignored.

[0089] The simplified AC potential distribution measurement equivalent valve module model is as follows: Figure 5 Parameter setting interface: Test the total number of converter valves in series.

[0090] In the impulse potential distribution measurement mode, the voltage-equalizing capacitor can equalize the voltage of each module under the impulse voltage. The impulse potential distribution is currently determined by measuring the peak value of the impulse voltage at each point. Under the action of the impulse voltage, the DC voltage-equalizing resistor and the equivalent resistance of the valve module cooling circuit do not change with the equivalent frequency of the impulse voltage wave head. The capacitive reactance of the RC circuit damping capacitor and the inductive reactance of the saturated reactor are closely related to the equivalent frequency of the impulse voltage wave head. Taking the operation impulse with the longest wave head time as an example, the typical operation impulse wave head time is 250μs, and the equivalent wave head frequency f=10 6 / 250=4000Hz. According to the capacitance impedance calculation formula: X C =1 / 2pifC, the equivalent capacitive reactance is in the mΩ level, which can be ignored compared to the damping resistor in the Ω level. According to the inductive reactance calculation formula: X L=2pifL, the equivalent inductive reactance of the saturated reactor is above Ω level. If the wave head time is shorter, the capacitive reactance value will be further reduced and the inductive reactance value will be further increased. The equivalent circuit of the impulse potential distribution measurement valve module is as follows Figure 6 Parameter setting interface: single valve series connection number, single stage damping resistance value, saturated reactor inductance median value, impulse voltage equivalent wave head time.

[0091] Due to the manufacturing process of saturated reactors and the characteristics of silicon steel sheets, the inductance of saturated reactors varies greatly, which has a great impact on the potential distribution measurement. Therefore, in the process of impulse potential measurement, the reactor potential measurement needs to be introduced separately.

[0092] 1. Waveform comparison and analysis function: compare the voltage waveform of the voltage generator output with the voltage waveform of each potential acquisition point. (1) For DC voltage, the voltage waveform of each measuring point in normal state and the ripple coefficient of the generator output voltage waveform. In abnormal state, the ripple coefficient of the voltage waveform of the abnormal measuring point is obviously higher or lower than the waveform output by the generator, or there is no voltage acquisition signal.

[0093] (2) For AC voltage, in normal state, the voltage waveform phase of each measuring point is consistent with the output waveform of the voltage generator, and the voltage amplitude of each measuring point does not exceed the device design deviation value; in abnormal state, the phase of the abnormal measuring point is different from other measuring points and the voltage generator, and the amplitude difference with other potential distribution measuring points exceeds the device design deviation value.

[0094] (3) For impulse voltage, under normal conditions, the oscillation frequency, wave head, and wave tail time of the voltage waveform at each measuring point are basically the same. The voltage amplitude at different module measuring points is related to the voltage division of the reactor of each module and the number of thyristors in the module. Assuming that module a where measuring point a is located contains p-class thyristors and module b where measuring point b is located contains q-class thyristors, and the two modules contain the same number of reactors, then U a ×p+U 电抗器a =U b ×q+U 电抗器b , abnormal state, does not meet any of the above conditions.

[0095] 2. Analysis of potential distribution unevenness:

[0096] The median value of the potential distribution is compared and analyzed with the voltage of each measuring point to give the unevenness of the tested potential distribution. The median value of the potential distribution is the sum of the voltage values ​​of each measuring point of the thyristor divided by the number of thyristor measuring points.

[0097] 3. Potential distribution calculation and diagnosis function:

[0098] This function includes calculating theoretical potential distribution and analyzing the causes of abnormal potential distribution. The proposed theoretical calculation method of potential distribution provides a basis for potential distribution measurement and fault analysis. The analysis of the causes of abnormal potential distribution gives the general reasons why various types of test voltages may cause abnormal potential distribution.

[0099] (1) DC voltage potential distribution. Assume that the output voltage of the voltage generator is U, the number of thyristors in series is n, the number of modules is 4, and the measurement point is any thyristor in each valve module a, b, c, d. The corresponding number of valve modules in series is N. a 、N b 、N c 、N d , and N a +N b +N c +N d =n, the resistance value of the thyristor-level voltage-equalizing circuit is R dc , the equivalent loop resistance in parallel with each valve module is R w-a , R w-b , R w-c , R w-d .

[0100] Taking the potential distribution at point a as an example, the theoretical potential distribution should be: U a =U×(N a ×R dc / / R w-a ) / {(N a ×R dc / / R w-a +N b ×R dc / / R w-b +N c ×R dc / / R w-c +N d ×R dc / / R w-a )×N a}, the measured value should be basically the same as the theoretical value, and the deviation should not exceed a% (production deviation of the equalizing resistor value).

[0101] Abnormal cause diagnosis criteria: 1) If the voltage at a certain measuring point is 0, and the test data at other measuring points are close to the theoretical value, then a short circuit fault occurs at the thyristor stage; 2) If the voltage at a certain measuring point deviates from the theoretical value by more than the production error, and the test data at other measuring points are close to the theoretical value, then the voltage equalization circuit component is faulty. 3) If the data at each measuring point deviates from the theoretical value, then there is a problem with the water circuit installation or the characteristics of the internal cooling medium.

[0102] (2) AC voltage potential distribution, assuming that the output voltage of the voltage generator is U, the number of thyristors in series is n, and the measurement point position is any thyristor in each valve module a, b, c, d, and the corresponding number of valve modules in series is N a 、N b 、N c 、N d , and N a +N b+N c +N d =n. It can be seen that in the case of no device damage, the theoretical potential distribution value U at any point is n Calculated as: U n = Utotal / n, assuming that the manufacturing tolerance of the damping capacitor is a%, the theoretical potential distribution value under AC voltage is U n (1±a%).

[0103] Abnormal cause diagnosis criteria: 1) If the voltage at the measuring point is 0 and the test data at other measuring points are close to the theory, a short circuit fault occurs at the thyristor level; 2) If the voltage amplitude at a certain measuring point deviates from the theoretical value by more than the production error or the waveform phase is different from the voltage generator, the damping circuit element at the measuring point is faulty. 3) If the voltage at each measuring point is significantly higher than the theoretical value, there is a multi-stage thyristor short circuit or wiring problem in the test circuit.

[0104] (3) Impulse voltage potential distribution, assuming that the output voltage of the voltage generator is U, the wave head time is T, the number of thyristors in series is n, the number of modules is 4, the measuring point positions a, b, c, d are any level of thyristors in each valve module, and the corresponding measuring point positions e, f, g, h are the reactors in each module. The corresponding number of valve modules in series is N a 、N b 、N c 、N d , and N a +N b +N c +N d =n, the inductance of the reactor is L. Taking point a as an example, the theoretical value of potential distribution is: (U / 4-2piL / T) / N a However, due to the manufacturing process of the saturated reactor, the inductance value under the impulse voltage fluctuates in the range of -20% to 20%. Therefore, it is necessary to collect the reactor potential and calculate the thyristor level potential: (U / 4-U e ) / N a ,U e is the valve module reactor voltage.

[0105] Abnormal analysis: 1) If the voltage at the measuring point is 0, the thyristor level is short-circuited; 2) The waveform parameters of each measuring point are the same as the output waveform of the voltage generator, U e Negative deviation exceeds 20%, U e +N a ×U a实测值 =U / 4, the saturated reactor is faulty; 3) The waveform parameters of each measuring point are the same as the output waveform of the voltage generator, U e Positive deviation, U e +N a ×U a实测值>U / 4, the thyristor in the module is faulty at a non-measurement point. 4) The waveform parameters of each measurement point are significantly different from the output waveform of the voltage generator. There are problems with the converter valve structure or the layout of the test circuit equipment, which introduces additional interference sources.

[0106] Example 2

[0107] Based on the same inventive concept, Figure 7 ,The present invention also provides a fault analysis system for a DC converter valve, comprising: a collection module and a fault analysis module;

[0108] The acquisition module is used to apply a test voltage to the DC converter valve using a voltage generator, and to collect voltages at various potential sampling points in the DC converter valve;

[0109] The fault analysis module is used to perform fault analysis on the DC converter valve based on the voltages at each potential sampling point;

[0110] The potential sampling point is any one level of thyristor in the valve module of the DC converter valve, and the test voltage is a DC voltage, an AC voltage or an impulse voltage.

[0111] Preferably, when the test voltage is a DC voltage, the fault analysis module is used to:

[0112] If the waveform ripple coefficients of the test voltage and the voltages at each potential sampling point are the same, the DC converter valve is in a normal state; otherwise, the DC converter valve is in an abnormal state.

[0113] Preferably, when the test voltage is a DC voltage, the fault analysis module is used to:

[0114] When the sampling voltage at the potential sampling point i is 0 and the difference between the sampling voltages at the other potential sampling points and their corresponding theoretical sampling voltages does not exceed the threshold, the thyristor at the potential sampling point i has a short circuit fault;

[0115] When the difference between the sampling voltage at the potential sampling point i and its corresponding theoretical sampling voltage exceeds the threshold and the differences between the sampling voltages at the remaining potential sampling points and their corresponding theoretical sampling voltages do not exceed the threshold, the voltage-equalizing circuit element corresponding to the thyristor at the potential sampling point i is faulty;

[0116] When the differences between the sampling voltages of all potential sampling points in the valve module to which the potential sampling point i belongs and their corresponding theoretical sampling voltages exceed the threshold, there is a water circuit installation or internal cooling medium failure in the valve module to which the potential sampling point i belongs.

[0117] Preferably, when the test voltage is a DC voltage, the theoretical voltage at the voltage collection point i in the fault analysis module is determined by the following formula:

[0118] U i =U×(N i ×R dc / / R w-i ) / {(∑N j ×R dc / / R wj )×N i}

[0119] Among them, U i is the theoretical voltage at the voltage collection point i, U is the test voltage, n is the total number of thyristors in series in the test converter valve, i,j∈[1,m], m is the number of valve modules in the converter valve, ∑N j =n,N i is the number of thyristors in the valve module to which the voltage acquisition point i belongs, N j is the number of thyristors in the valve module to which the voltage acquisition point j belongs, R dc is the resistance value of the voltage-equalizing loop, R wj is the equivalent water circuit resistance value of the valve module in parallel to the voltage collection point j, R w-i is the equivalent loop resistance connected in parallel with the valve module at the potential sampling point i.

[0120] Preferably, when the test voltage is an AC voltage, the fault analysis module is used to:

[0121] If the output waveforms of the test voltage and the voltages at each potential sampling point are consistent and the amplitude difference between the test voltage and the voltages at each potential sampling point does not exceed a threshold, the DC converter valve is in a normal state; otherwise, the DC converter valve is in an abnormal state.

[0122] Preferably, when the test voltage is an AC voltage, the fault analysis module is used to:

[0123] When the sampling voltage at the potential sampling point i is 0 and the difference between the sampling voltages at the other potential sampling points and their corresponding theoretical sampling voltages does not exceed the threshold, the thyristor at the potential sampling point i has a short circuit fault;

[0124] When the difference between the sampling voltage at the potential sampling point i and the corresponding theoretical sampling voltage exceeds the threshold or when the waveform phase deviation between the sampling voltage at the potential sampling point i and the corresponding theoretical sampling voltage exceeds the threshold, the damping circuit element corresponding to the thyristor at the potential sampling point i is faulty;

[0125] When the sampling voltages of all potential sampling points in the valve module to which the potential sampling point i belongs are higher than their corresponding theoretical sampling voltages and the difference between them exceeds the threshold, there is a multi-stage thyristor short circuit or wiring fault in the valve module to which the potential sampling point belongs.

[0126] Preferably, when the test voltage is an AC voltage, the theoretical voltage at the voltage collection point i in the fault analysis module is determined by the following formula:

[0127] U i =U / n;

[0128] Among them, U i is the theoretical voltage at the voltage collection point i, U is the test voltage, and n is the total number of thyristors in series for the test converter valve.

[0129] Preferably, when the test voltage is an impulse voltage, the fault analysis module is used to:

[0130] If the time difference between the wave head and the wave tail of the voltage waveform at each potential sampling point does not exceed the threshold and satisfies U i ×x+U 电抗器i =U j ×y+U 电抗器j , the DC converter valve is in a normal state, otherwise, the DC converter valve is in an abnormal state;

[0131] Among them, U i is the theoretical voltage at the voltage collection point i, U j is the theoretical voltage at voltage collection point j, U 电抗器i is the voltage of the valve module reactor at the potential sampling point i, U 电抗器j is the voltage of the inductor of the valve module at the potential sampling point j, x is the number of thyristors in series of the valve module at the potential sampling point i, and y is the number of thyristors in series of the valve module at the potential sampling point j.

[0132] Preferably, when the test voltage is an impulse voltage, the fault analysis module is used to:

[0133] When the sampling voltage at the potential sampling point i is 0, there is a short-circuit fault in the thyristor at the potential sampling point i;

[0134] When the sampling voltage at the potential sampling point i is the same as the corresponding theoretical sampling voltage waveform parameter, the negative deviation of the voltage of the reactor of the valve module at the potential sampling point i exceeds the threshold, and the product of the voltage of the reactor of the valve module at the potential sampling point i plus the number of series thyristors of the valve module at the potential sampling point i and the sampling voltage at the potential sampling point i is equal to the set fraction of the test voltage, the reactor in the valve module at the potential sampling point i is faulty;

[0135] When the sampling voltage at the potential sampling point i is the same as the corresponding theoretical sampling voltage waveform parameter, and the reactor voltage of the valve module to which the potential sampling point i belongs is greater than the set fraction of the test voltage, the thyristor at the non-potential sampling point i of the valve module to which the potential sampling point i belongs is faulty;

[0136] When the waveform parameters of the sampled voltage at the potential acquisition point i differ from the waveform parameters of the test voltage by more than a threshold, the converter valve structure or the test circuit equipment layout fails;

[0137] The waveform parameters include wave head time and wave tail time.

[0138] In summary, the present invention provides a method for measuring the potential distribution and analyzing data of a DC converter valve, including: applying a test voltage to the DC converter valve using a voltage generator, and collecting the voltages at each potential sampling point in the DC converter valve; and performing a fault analysis on the DC converter valve based on the voltages at each potential sampling point. The present invention establishes a potential distribution test electrical model for various types of test voltages, proposes a potential distribution theoretical calculation method and an analysis of the causes of potential distribution anomalies, thereby achieving targeted testing and analysis, verifying the correctness of the converter valve design, and analyzing the causes of circuit anomalies.

[0139] Obviously, the described embodiments are only some embodiments of the present invention, but not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0140] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems, or computer program products. Therefore, the present application may adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment in combination with software and hardware. Moreover, the present application may adopt the form of a computer program product implemented in one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) that include computer-usable program code.

[0141] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0142] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0143] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0144] The above are merely embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention are included in the scope of the claims of the present invention to be approved.

Claims

1. A fault analysis method for a DC converter valve, characterized in that: include: A voltage generator is used to apply a test voltage to the DC converter valve, and the voltage of each potential sampling point in the DC converter valve is collected; Performing fault analysis on the DC converter valve based on the voltages at each potential sampling point; The potential sampling point is any one level of thyristor in the valve module of the DC converter valve, and the test voltage is a DC voltage, an AC voltage or an impulse voltage.

2. The method according to claim 1, characterized in that When the test voltage is a DC voltage, the fault analysis of the DC converter valve based on the voltage data of each potential sampling point includes: If the waveform ripple coefficients of the test voltage and the voltages at each potential sampling point are the same, the DC converter valve is in a normal state; otherwise, the DC converter valve is in an abnormal state.

3. The method according to claim 1, characterized in that When the test voltage is a DC voltage, the fault analysis of the DC converter valve based on the voltage data of each potential sampling point includes: When the sampling voltage at the potential sampling point i is 0 and the difference between the sampling voltages at the other potential sampling points and their corresponding theoretical sampling voltages does not exceed the threshold, the thyristor at the potential sampling point i has a short circuit fault; When the difference between the sampling voltage at the potential sampling point i and its corresponding theoretical sampling voltage exceeds the threshold and the differences between the sampling voltages at the remaining potential sampling points and their corresponding theoretical sampling voltages do not exceed the threshold, the voltage-equalizing circuit element corresponding to the thyristor at the potential sampling point i is faulty; When the differences between the sampling voltages of all potential sampling points in the valve module to which the potential sampling point i belongs and their corresponding theoretical sampling voltages exceed the threshold, there is a water circuit installation or internal cooling medium failure in the valve module to which the potential sampling point i belongs.

4. The method according to claim 3, characterized in that The theoretical voltage at the voltage collection point i is determined by the following formula: U i =U×(N i ×R dc / / R w-i ) / {(∑N j ×R dc / / R wj )×N i } Among them, U i is the theoretical voltage at the voltage collection point i, U is the test voltage, n is the total number of thyristors in series in the test converter valve, i,j∈[1,m], m is the number of valve modules in the converter valve, ∑N j =n,N i is the number of thyristors in the valve module to which the voltage acquisition point i belongs, N j is the number of thyristors in the valve module to which the voltage acquisition point j belongs, R dc is the resistance value of the voltage-equalizing loop, R wj is the equivalent water circuit resistance value of the valve module in parallel to the voltage collection point j, R w-i is the equivalent loop resistance connected in parallel with the valve module at the potential sampling point i.

5. The method according to claim 1, characterized in that When the test voltage is an AC voltage, the fault analysis of the DC converter valve based on the voltage data of each potential sampling point includes: If the output waveforms of the test voltage and the voltages at each potential sampling point are consistent and the amplitude difference between the test voltage and the voltages at each potential sampling point does not exceed a threshold, the DC converter valve is in a normal state; otherwise, the DC converter valve is in an abnormal state.

6. The method according to claim 1, characterized in that When the test voltage is an AC voltage, the fault analysis of the DC converter valve based on the voltage data of each potential sampling point includes: When the sampling voltage at the potential sampling point i is 0 and the difference between the sampling voltages at the other potential sampling points and their corresponding theoretical sampling voltages does not exceed the threshold, the thyristor at the potential sampling point i has a short circuit fault; When the difference between the sampling voltage at the potential sampling point i and the corresponding theoretical sampling voltage exceeds the threshold or when the waveform phase deviation between the sampling voltage at the potential sampling point i and the corresponding theoretical sampling voltage exceeds the threshold, the damping circuit element corresponding to the thyristor at the potential sampling point i is faulty; When the sampling voltages of all potential sampling points in the valve module to which the potential sampling point i belongs are higher than their corresponding theoretical sampling voltages and the difference between them exceeds the threshold, there is a multi-stage thyristor short circuit or wiring fault in the valve module to which the potential sampling point belongs.

7. The method according to claim 6, characterized in that The theoretical voltage at the voltage collection point i is determined by the following formula: U i =U / n; Among them, U i is the theoretical voltage at the voltage collection point i, U is the test voltage, and n is the total number of thyristors in series for the test converter valve.

8. The method according to claim 1, characterized in that When the test voltage is an impulse voltage, the fault analysis of the DC converter valve based on the voltage data of each potential sampling point includes: If the time difference between the wave head and the wave tail of the voltage waveform at each potential sampling point does not exceed the threshold and satisfies U i ×x+U 电抗器i =U j ×y+U 电抗器j , the DC converter valve is in a normal state, otherwise, the DC converter valve is in an abnormal state; Among them, U i is the theoretical voltage at the voltage collection point i, U j is the theoretical voltage at voltage collection point j, U 电抗器i is the voltage of the valve module reactor at the potential sampling point i, U 电抗器j is the voltage of the reactor of the valve module at the potential sampling point j, x is the number of thyristors in series of the valve module at the potential sampling point i, and y is the number of thyristors in series of the valve module at the potential sampling point j.

9. The method according to claim 1, characterized in that When the test voltage is an impulse voltage, the fault analysis of the DC converter valve based on the voltage data of each potential sampling point includes: When the sampling voltage at the potential sampling point i is 0, there is a short-circuit fault in the thyristor at the potential sampling point i; When the sampling voltage at the potential sampling point i is the same as the corresponding theoretical sampling voltage waveform parameter, the negative deviation of the voltage of the reactor of the valve module at the potential sampling point i exceeds the threshold, and the product of the voltage of the reactor of the valve module at the potential sampling point i plus the number of series thyristors of the valve module at the potential sampling point i and the sampling voltage at the potential sampling point i is equal to the set fraction of the test voltage, the reactor in the valve module at the potential sampling point i is faulty; When the sampling voltage at the potential sampling point i is the same as the corresponding theoretical sampling voltage waveform parameter, and the reactor voltage of the valve module to which the potential sampling point i belongs is greater than the set fraction of the test voltage, the thyristor at the non-potential sampling point i of the valve module to which the potential sampling point i belongs is faulty; When the waveform parameters of the sampled voltage at the potential acquisition point i differ from the waveform parameters of the test voltage by more than a threshold, the converter valve structure or the test circuit equipment layout fails; The waveform parameters include wave head time and wave tail time.

10. A fault analysis system for a DC converter valve, characterized in that: include: Acquisition module and fault analysis module; The acquisition module is used to apply a test voltage to the DC converter valve using a voltage generator, and to collect voltages at various potential sampling points in the DC converter valve; The fault analysis module is used to perform fault analysis on the DC converter valve based on the voltages at each potential sampling point; The potential sampling point is any one level of thyristor in the valve module of the DC converter valve, and the test voltage is a DC voltage, an AC voltage or an impulse voltage.

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