Converter short-circuit fault positioning method and device based on valve conduction state, and medium

Abstract

The invention discloses a converter short-circuit fault positioning method and device based on a valve conduction state and a medium, and relates to the technical field of direct-current power grid control and protection. The method determines that a fault occurs in an alternating current side area, a valve body area or a direct current side area of the converter according to action conditions of valve short circuit protection and thyristor protection at different fault positions and three-phase current characteristics of the alternating current side of the converter, and determines whether the fault occurs or not according to a fault occurrence moment and a protection action moment. According to the method, the conduction state of the converter valve at the fault occurrence moment is determined, and the short-circuit fault of each converter valve in the converter valve body area is accurately positioned according to the conduction state of the converter valve at the fault occurrence moment, so that the positioning precision and the positioning feasibility of the short-circuit fault of the converter are improved based on the existing hardware.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of direct current power grid control and protection, in particular to a converter short-circuit fault positioning method and device based on valve conduction state and a medium. BACKGROUND

[0002] As the core equipment of high-voltage direct current transmission system, the converter plays an important role in the AC-DC conversion of the power grid. In order to prevent converter short-circuit faults, valve short-circuit protection and thyristor monitoring protection are usually configured.

[0003] In the prior art, when positioning the short-circuit fault of the converter, the change characteristics of the monitored fault electrical quantity are analyzed to determine the fault, or a detection point is additionally added to each bridge arm of the converter to position the faulty converter valve in the valve body area.

[0004] However, the method of analyzing the change characteristics of the monitored fault electrical quantity can only determine that the fault occurs in the valve body area, but cannot specifically locate the faulty converter valve, and the positioning accuracy is low. The method of additionally adding a detection point to each bridge arm of the converter has high cost and poor feasibility. Therefore, the prior art has the defects of low fault positioning accuracy and poor feasibility when positioning the short-circuit fault of the converter. SUMMARY

[0005] The present application relates to the technical field of direct current power grid control and protection, in particular to a converter short-circuit fault positioning method and device based on valve conduction state and a medium.

[0006] The present application relates to the technical field of direct current power grid control and protection, in particular to a converter short-circuit fault positioning method and device based on valve conduction state and a medium. In a first aspect, the present application provides a converter short-circuit fault positioning method based on valve conduction state, comprising: obtaining a protection action time of valve short-circuit protection action; in the continuously recorded fault recording data, obtaining a characteristic quantity waveform at the time of valve short-circuit, and identifying a mutation time of the characteristic quantity waveform as a fault occurrence time; obtaining conduction identification bits and reference area identification bits of each converter valve in the converter according to the fault occurrence time, wherein the conduction identification bits are used to indicate the converter valve in the conduction state at the fault occurrence time, and the reference area identification bits are used to indicate the area of the valve short-circuit protection action at the protection action time; establishing a target time period according to the fault occurrence time and the protection action time; In the target time period, three-phase current characteristic information of the AC side of the converter is calculated, wherein the three-phase current characteristic information comprises integral and maximum value of each three-phase current; According to the conduction identification bit, the three-phase current characteristic information and the reference region identification bit, a target short-circuit fault position is determined.

[0007] In a possible design, the conduction identification bit and the reference region identification bit of each converter valve in the converter at the fault occurrence time are obtained according to the following steps: A first measurement time period is established according to a difference between the fault occurrence time and a first preset value and a sum of the fault occurrence time and a second preset value, wherein the first preset value is smaller than the second preset value; In the fault recording data, A-phase current data of the AC side of the converter in the first measurement time period is retrieved, wherein the A-phase current data comprises A-phase current values at multiple different times; According to the fault occurrence time, a preset number of A-phase current values that are continuously and sequentially increased from zero are obtained, and a time corresponding to a current value of zero is marked as a candidate occurrence time, so as to obtain multiple candidate occurrence times; In the multiple candidate occurrence times, a candidate occurrence time closest to the fault occurrence time is taken as a reference occurrence time; A first intermediate difference between the fault occurrence time and the reference occurrence time is obtained, the first intermediate difference is compared with a preset reference time to obtain a first comparison result, and the conduction identification bit is obtained according to the first comparison result; A second intermediate difference between the protection action time and the reference occurrence time is obtained, the second intermediate difference is compared with the preset reference time to obtain a second comparison result, and the reference region identification bit is obtained according to the second comparison result; wherein the preset reference time comprises a first preset time and a second preset time, and the first preset time is smaller than the second preset time.

[0008] In a possible design, the conduction identification bit is obtained according to the first comparison result, including: If the first comparison result indicates that the first intermediate difference is smaller than the first preset time, the conduction identification bit is a first conduction identification number, and the first conduction identification number indicates that, at the fault occurrence time, a fifth converter valve and a sixth converter valve are in a conduction state; If the first intermediate difference is greater than or equal to the first preset time and smaller than a sum of the first preset time and the second preset time, the conduction identification bit is a second conduction identification number, and the second conduction identification number indicates that, at the fault occurrence time, a first converter valve and the sixth converter valve are in a conduction state. if the first intermediate difference value is greater than or equal to a sum of the first preset time and twice the second preset time, and less than a sum of the first preset time and three times the second preset time, the conduction identification bit is a fourth conduction identification number, the fourth conduction identification number indicates that at the fault occurrence moment, the second converter valve and the third converter valve are in a conduction state; if the first intermediate difference value is greater than or equal to a sum of the first preset time and twice the second preset time, and less than a sum of the first preset time and three times the second preset time, the conduction identification bit is a fourth conduction identification number, the fourth conduction identification number indicates that at the fault occurrence moment, the second converter valve and the third converter valve are in a conduction state; if the first intermediate difference value is greater than or equal to a sum of the first preset time and three times the second preset time, and less than a sum of the first preset time and four times the second preset time, the conduction identification bit is a fifth conduction identification number, the fifth conduction identification number indicates that at the fault occurrence moment, the third converter valve and the fourth converter valve are in a conduction state; if the first intermediate difference value is greater than or equal to a sum of the first preset time and four times the second preset time, and less than a sum of the first preset time and five times the second preset time, the conduction identification bit is a sixth conduction identification number, the sixth conduction identification number indicates that at the fault occurrence moment, the fourth converter valve and the fifth converter valve are in a conduction state; if the first intermediate difference value is greater than or equal to a sum of the first preset time and five times the second preset time, and less than a sum of the first preset time and six times the second preset time, the conduction identification bit is a first conduction identification number, the first conduction identification number indicates that at the fault occurrence moment, the fifth converter valve and the sixth converter valve are in a conduction state.

[0009] In a possible design, the reference region identification bit is obtained according to the second comparison result, including: if the second comparison result indicates that the second intermediate difference value is less than the first preset time, the reference region identification bit is a first region identification bit, the first region identification bit indicates that at the protection action moment, a region where the protection action is located is a first reference region; if the second intermediate difference value is greater than or equal to the first preset time, and less than a sum of the first preset time and the second preset time, the reference region identification bit is a second region identification bit, the second region identification bit indicates that at the protection action moment, a region where the protection action is located is a second reference region; If the second intermediate difference value is greater than or equal to a sum of the first preset time and the second preset time and less than a sum of twice the first preset time and the second preset time, the reference region identifier is a third region identifier, and the third region identifier indicates that the region where the protection action is located at the protection action time is a third reference region. If the second intermediate difference value is greater than or equal to a sum of the first preset time and twice the second preset time and less than a sum of the first preset time and thrice the second preset time, the reference region identifier is a fourth region identifier, and the fourth region identifier indicates that the region where the protection action is located at the protection action time is a fourth reference region. If the second intermediate difference value is greater than or equal to a sum of the first preset time and thrice the second preset time and less than a sum of the first preset time and quadruple the second preset time, the reference region identifier is a fifth region identifier, and the fifth region identifier indicates that the region where the protection action is located at the protection action time is a fifth reference region. If the second intermediate difference value is greater than or equal to a sum of the first preset time and quadruple the second preset time and less than a sum of the first preset time and quintuple the second preset time, the reference region identifier is a sixth region identifier, and the sixth region identifier indicates that the region where the protection action is located at the protection action time is a sixth reference region. If the second intermediate difference value is greater than or equal to a sum of the first preset time and quintuple the second preset time and less than a sum of the first preset time and sextuple the second preset time, the reference region identifier is a first region identifier, and the first region identifier indicates that the region where the protection action is located at the protection action time is a first reference region.

[0010] In a possible design, the calculation of the three-phase current characteristic information of the AC side of the converter in the target time period includes the following steps. The first instantaneous current data of the A-phase current, the B-phase current, and the C-phase current in the target time period is obtained, where the first instantaneous current data includes current instantaneous values at multiple time points. The integral of the instantaneous current data of each phase current in the target time period is calculated to obtain the A-phase current integral, the B-phase current integral, and the C-phase current integral. The second measurement time period is established according to the protection action time, and the maximum current value is calculated in the second measurement time period.

[0011] In a possible design, a second measurement time period is established according to the protection action time, and the current maximum value is calculated by obtaining, in the second measurement time period, second instantaneous current data of A-phase current, B-phase current and C-phase current in the three-phase current, the second instantaneous current data including current instantaneous values at multiple time points, and taking the current instantaneous value with the largest absolute value in the second instantaneous current data as the current maximum value. The second measurement time period is established according to a sum of the protection action time and a third preset value, and a sum of the protection action time and a fourth preset value, wherein the third preset value is smaller than the fourth preset value, the third preset value is greater than the first preset value, and the third preset value is smaller than the second preset value. The A-phase current, the B-phase current and the C-phase current in the three-phase current are obtained, second instantaneous current data in the second measurement time period is obtained, the second instantaneous current data including current instantaneous values at multiple time points, and the current instantaneous value with the largest absolute value in the second instantaneous current data is taken as the current maximum value.

[0012] In a possible design, the target short-circuit fault position is determined according to the conduction identification bit, the three-phase current characteristic information and the reference region identification bit. If the current maximum value is greater than or equal to the current threshold value, the target short-circuit fault position is the AC side of the converter. If the current maximum value is smaller than the preset current threshold value, it is detected whether the thyristor monitoring protection is in action. If not, the target short-circuit fault position is the DC side of the converter. If yes, the target short-circuit fault position is determined according to the conduction identification bit and the integral of each three-phase current.

[0013] In a possible design, the target short-circuit fault position is determined according to the conduction identification bit and the integral of each three-phase current. In a fault criterion database, a corresponding fault criterion is obtained according to the conduction identification bit, as a target fault criterion, and the target fault criterion is implemented based on the integral of each three-phase current, to obtain the target short-circuit fault position. The fault criterion database pre-stores a plurality of groups of different conduction identification bits and fault criteria, the fault criterion includes a judgment logic chain about the integral of each three-phase current and the reference region identification bit, and the judgment logic chain points to a corresponding converter valve at the end, as the short-circuit fault position.

[0014] In a second aspect, the present application provides a converter short-circuit fault positioning device based on valve conduction state, including: The acquisition module is configured to acquire a protection action time of valve short-circuit protection action, acquire a characteristic quantity waveform at the time of valve short-circuit in the continuously recorded fault recording data, and identify a mutation time of the characteristic quantity waveform as a fault occurrence time. The first processing module is used for acquiring the conduction identification bit and the reference area identification bit of each valve in the converter according to the fault occurrence time, wherein the conduction identification bit is used for indicating the valve in the conduction state at the fault occurrence time, and the reference area identification bit is used for indicating the area of the valve short-circuit protection action at the protection action time. The second processing module is used for establishing a target time period according to the fault occurrence time and the protection action time, and calculating the three-phase current characteristic information of the AC side of the converter in the target time period, wherein the three-phase current characteristic information includes the integral and the maximum value of each three-phase current. The positioning module is used for determining the target short-circuit fault position according to the conduction identification bit, the three-phase current characteristic information and the reference area identification bit.

[0015] In a third aspect, the present application provides a computer readable storage medium, wherein the computer readable storage medium stores computer execution instructions, and the computer execution instructions are used for realizing the valve conduction state-based converter short-circuit fault positioning method when executed by a processor.

[0016] Compared with the prior art, the present application has the following advantages and beneficial effects: The present application determines that the fault occurs in the AC side area, the valve body area or the DC side area of the converter by the action of the valve short-circuit protection and the thyristor protection at different fault positions and the three-phase current characteristics of the AC side of the converter, determines the conduction state of the valve at the fault occurrence time according to the judgment of the fault occurrence time and the protection action time, and further realizes the accurate positioning of the short-circuit fault of each valve in the valve body area of the converter according to the conduction state of the valve at the fault occurrence time, thereby improving the positioning accuracy and the positioning feasibility of the converter short-circuit fault based on the existing hardware. BRIEF DESCRIPTION OF DRAWINGS

[0017] In order to more clearly illustrate the technical solutions of the example embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiments. It should be understood that the following drawings only show some embodiments of the present application, and therefore should not be considered as a limitation to the scope. For those skilled in the art, other related drawings can also be obtained without creative labor. In the drawings: Figure 1 It is a schematic diagram of the fault position of the converter; Figure 2 It is a valve conduction state-based converter short-circuit fault positioning method flowchart provided by the present application Figure 1 ; Figure 3 It is a valve conduction state-based converter short-circuit fault positioning method flowchart provided by the present application Figure 2; Figure 4 Schematic diagram of the process of fault judgment provided in the embodiment of this application Figure 1 ; Figure 5 Schematic diagram of the process of fault judgment provided in the embodiment of this application Figure 2 ; Figure 6 The short circuit simulation results provided in this embodiment are shown as follows Figure 1 ; Figure 7 The short circuit simulation results provided in this embodiment are shown as follows Figure 2 ; Figure 8 A schematic structural diagram of a converter short-circuit fault locating device based on valve conduction state provided in an embodiment of the present application. DETAILED DESCRIPTION

[0018] The exemplary embodiments will be described in detail herein, examples of which are shown in the accompanying drawings. When the following description refers to the drawings, the same numbers in different drawings represent the same or similar elements, unless otherwise indicated. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present application. On the contrary, they are merely examples of devices and methods consistent with some aspects of the present application as detailed in the appended claims, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0019] The converter short-circuit fault locations include three types: converter AC side phase short-circuit fault, converter valve short-circuit fault and converter DC side short-circuit fault.

[0020] Figure 1 is a schematic diagram of the converter fault location, as shown in Figure 1 As shown, the interphase short circuit fault location of the converter AC side includes AB, AC and BC interphase short circuits. For example, the AB interphase short circuit fault is f 1; The converter valve short circuit fault location includes the first converter valve V1 short circuit, that is, f 21 , the second converter valve V2 is short-circuited, that is, f 22 , the third converter valve V3 is short-circuited, that is, f 23 , the fourth converter valve V4 is short-circuited, that is, f 24 , the fifth converter valve V5 is short-circuited, that is, f 25 , the sixth converter valve V6 is short-circuited, that is, f 26; the direct current side short circuit fault is a pulsating converter bridge direct current outlet short circuit fault f 3. Since all the short circuit faults in the above positions will trigger valve short circuit protection action, the valve short circuit protection has a one-to-many relationship with the fault position, and the fault positioning of the converter cannot be realized through the protection action result.

[0021] The prior art uses the integral result of the fault electrical quantity to construct a fault criterion by analyzing the change characteristics of the fault electrical quantity when the ground fault and the short circuit fault occur in the converter area, so as to realize the determination of the converter area AC side ground\short circuit fault, the converter valve short circuit fault and the DC side ground\short circuit fault, but this scheme cannot specifically locate the short circuit fault converter valve and can only determine that the fault occurs in the valve body area, and the positioning accuracy is low.

[0022] The prior art also realizes the positioning of the valve body area fault converter valve by additionally installing a measuring point on each bridge arm of the converter and integrating the three-phase currents of the converter AC side and the currents of each bridge arm, and uses the relationship of the current integral result, but this scheme needs to increase the installation cost and is not conducive to implementation, that is, the feasibility is poor, so the prior art has the defects of low fault positioning accuracy and poor feasibility.

[0023] Therefore, the present application provides a converter short circuit fault positioning method based on valve conduction state, by obtaining the protection action time indicating the valve short circuit protection action and the fault occurrence time when the valve short circuit occurs, obtaining the conduction identification bit and the reference area identification bit of each converter valve in the converter, according to the fault occurrence time and the protection action time, establishing a target time period, in the target time period, calculating the three-phase current characteristic information of the AC side of the converter, wherein the three-phase current characteristic information includes the integral and the maximum value of each three-phase current, determining the target short circuit fault position of each converter valve according to the conduction identification bit, the three-phase current characteristic information and the reference area identification bit, thereby improving the fault positioning accuracy and the feasibility.

[0024] The technical solutions of the present application and how the technical solutions of the present application solve the above technical problems will be described in detail below with specific embodiments. The following specific embodiments can be combined with each other, and the same or similar concepts or processes can not be described again in some embodiments. The embodiments of the present application will be described below with reference to the accompanying drawings.

[0025] Embodiment one Figure 2 The converter short circuit fault positioning method based on valve conduction state provided by the embodiment of the present application Figure 1 As shown in the method, the method comprises the following steps. Figure 2 S101, obtaining the protection action time of the valve short circuit protection action.

[0026] ​Specifically, the action of the valve short-circuit protection in the converter station of the high-voltage direct current transmission system is monitored, and if it is monitored that the valve short-circuit protection performs a protection action, the time point of the valve short-circuit protection action at this time is marked as a protection action time point t on .

[0027] S102, in the continuously recorded fault recording data, a characteristic quantity waveform at the time of valve short-circuit is obtained, and a mutation time of the characteristic quantity waveform is identified as a fault occurrence time.

[0028] Specifically, after it is monitored that the protection action time point t on is obtained, in the fault recording data, a valve short-circuit protection characteristic quantity waveform i diff is called. i diff The normal value of the characteristic quantity waveform i diff under the normal operating condition is zero, and when it is identified that the characteristic quantity waveform i diff exceeds zero, the mutation time at this time is taken as the fault occurrence time t f .

[0029] S103, according to the fault occurrence time, a conduction identification bit and a reference area identification bit of each valve in the converter are obtained.

[0030] Specifically, after the protection action time point t on and the fault occurrence time t f are obtained, a first measurement time period is established according to the fault occurrence time t f , in the fault recording data, three-phase current data in the first measurement time is called, and according to the three-phase current data in the first measurement time, a conduction identification bit of a conduction state of the valve at the fault occurrence time t f is determined, and according to the protection action time point t on , a reference area identification bit indicating the area where the valve short-circuit protection action is located is obtained.

[0031] Wherein, the conduction identification bit is used to indicate the valve in the conduction state at the fault occurrence time t f , and the reference area identification bit is used to indicate the area where the valve short-circuit protection action is located at the protection action time point.

[0032] S104, according to the fault occurrence time and the protection action time point, a target time period is established.

[0033] Specifically, after the conduction identification bit and the reference area identification bit are obtained, the fault occurrence time t f is taken as a starting time point, and the protection action time point t onAs the end time, to achieve the establishment of the target time period (t f , t on ).

[0034] S105, in the target time period, calculate the three-phase current characteristic information of the converter AC side, wherein the three-phase current characteristic information includes the integral and current maximum of each three-phase current.

[0035] S106, according to the conduction identification bit, the three-phase current characteristic information and the reference area identification bit to determine the target short circuit fault position.

[0036] Specifically, after obtaining the three-phase current characteristic information including the integral and current maximum of each three-phase current, according to the current maximum and the thyristor monitoring protection action, the fault position is determined as the converter AC side, the converter DC side or the converter valve area, if the fault position is determined as the short circuit in the converter valve area, according to the conduction identification bit, the reference area identification bit and the integral of each three-phase current, the specific short circuit fault position of the converter valve in the converter is further determined, so as to realize the accurate positioning of the short circuit fault in the valve area.

[0037] The embodiment of the application provides a kind of based on valve conduction state's converter short circuit fault positioning method, by the protection action time indicating valve short circuit protection action obtained, and the fault occurrence time when valve short circuit, after obtaining the conduction identification bit and reference area identification bit of each converter valve in the converter, according to the fault occurrence time and protection action time, establish target time period, in target time period, calculate the three-phase current characteristic information of the converter AC side, wherein the three-phase current characteristic information includes the integral and current maximum of each three-phase current, according to the conduction identification bit, three-phase current characteristic information and reference area identification bit determine the target short circuit fault position of each converter valve, to improve the fault positioning precision and feasibility.

[0038] Embodiment two Figure 3 The valve conduction state based converter short circuit fault positioning method provided in the embodiment of the application is shown in the flow chart Figure 2 . As Figure 3 shown, the method comprises: S201, obtain protection action time and fault occurrence time.

[0039] Specifically, the content of this step is same as the content of step S101 and step 102, which will not be repeated here.

[0040] S202, according to the difference between the fault occurrence time and the first preset value, and the sum of the fault occurrence time and the second preset value, establish the first measurement time period.

[0041] Specifically, after obtaining the protection action time ton and the fault occurrence time t f Afterwards, according to the fault occurrence time t f and the difference between the first preset value such as m1=20ms and the fault occurrence time t f and the difference between the second preset value such as n1=40ms, a first measurement time period (t f -m1, t f +n1) is established, wherein the first preset value m1 is smaller than the second preset value n1.

[0042] S203, in the fault recording data, the A-phase current data of the converter AC side within the first measurement time period is called, and the A-phase current data includes A-phase current values at multiple different times.

[0043] Specifically, in the fault recording data, the three-phase current data of the converter AC side within the first measurement time period (t f -m1, t f +n1) is called, that is, the A-phase current data i A , B-phase current data i B and C-phase current data i C , wherein each phase current data includes multiple current values at different times.

[0044] S204, based on the fault occurrence time, a reference occurrence time is obtained.

[0045] Specifically, after the A-phase current data i A is obtained, the A-phase current data i A is found from the time closest to the fault occurrence time t f , and the time from which the A-phase current data i A increases continuously by a preset number such as five measurement values in sequence is found, and after the time at which the A-phase current data f is zero is marked as a candidate occurrence time, multiple candidate occurrence times are obtained, and among the multiple candidate occurrence times, the candidate occurrence time closest to the fault occurrence time is taken as the reference occurrence time t0.

[0046] S205, a first intermediate difference value between the fault occurrence time and the reference occurrence time is obtained.

[0047] Specifically, after the reference occurrence time t0 is obtained, the difference between the fault occurrence time t f and the reference occurrence time t0, that is, the first intermediate difference value a=t f -t0, is obtained.

[0048] S206, compare the first intermediate difference value with a preset reference time to obtain a first comparison result, and obtain the conduction identification bit according to the first comparison result.

[0049] Specifically, after obtaining the first intermediate difference value a, the first intermediate difference value a is compared with a first preset time t1 and a second preset time t2 in the preset reference time, wherein the first preset time t1 is less than the second preset time t2, such as 1 ms and 3.3 ms.

[0050] Further, if the first comparison result indicates that the first intermediate difference value a is less than the first preset time t1, that is, when t0 f -t0 f , the fifth converter valve V5 and the sixth converter valve V6 are in the conduction state.

[0051] Further, if the first intermediate difference value a is greater than or equal to the first preset time t1 and less than the sum of the first preset time t1 and the second preset time t2, that is, when t1 f -t0 f , the first converter valve V1 and the sixth converter valve V6 are in the conduction state.

[0052] Further, if the first intermediate difference value a is greater than or equal to the sum of the first preset time t1 and the second preset time t2 and less than the sum of the first preset time t1 and twice the second preset time t2, that is, t1 f -t0 f , the first converter valve V1 and the second converter valve V2 are in the conduction state.

[0053] Further, if the first intermediate difference value a is greater than or equal to the sum of the first preset time t1 and twice the second preset time t2 and less than the sum of the first preset time t1 and thrice the second preset time t2, that is, t1 f -t0 f , the second converter valve V2 and the third converter valve V3 are in the conduction state.

[0054] Further, if the first intermediate difference value a is greater than or equal to a sum of the first preset time t1 and three times of the second preset time t2, and less than a sum of the first preset time t1 and four times of the second preset time t2, i.e., t1+3t2≤t f -t0<t1+4t2, the on identification bit S is a fifth on identification number such as 5, and the fifth on identification number indicates that at the fault occurrence time t f , the third converter valve V3 and the fourth converter valve V4 are in the on state.

[0055] Further, if the first intermediate difference value a is greater than or equal to a sum of the first preset time t1 and four times of the second preset time t2, and less than a sum of the first preset time t1 and five times of the second preset time t2, i.e., t1+4t2≤t f -t0<t1+5t2, the on identification bit S is a sixth on identification number such as 6, and the sixth on identification number indicates that at the fault occurrence time t f , the fourth converter valve V4 and the fifth converter valve V5 are in the on state.

[0056] Further, if the first intermediate difference value a is greater than or equal to a sum of the first preset time t1 and five times of the second preset time t2, and less than a sum of the first preset time t1 and six times of the second preset time t2, i.e., t1+5t2≤t f -t0<t1+6t2, the on identification bit S is a first on identification number 1, and the first on identification number indicates that at the fault occurrence time t f , the fifth converter valve V5 and the sixth converter valve V6 are in the on state.

[0057] S207, obtaining a second intermediate difference value of the protection action time and the reference occurrence time.

[0058] Specifically, after the reference occurrence time t0 is obtained, a difference between the protection action time t on and the reference occurrence time t0 is taken as the second intermediate difference value b=t on -t0.

[0059] S208, comparing the second intermediate difference value with the preset reference time to obtain a second comparison result, and obtaining the reference region identification bit according to the second comparison result.

[0060] Specifically, if the second comparison result indicates that the second intermediate difference value b is less than the first preset time t1, i.e., t on -t0<t1, the reference region identification bit T is a first region identification bit such as 1, and the first region identification bit indicates that at the protection action time t on , the region of the protection action is a first reference region.

[0061] Further, if the second intermediate difference b is greater than or equal to the first preset time t1 and less than the sum of the first preset time t1 and the second preset time t2, i.e. t1≤t on -t0

[0062] Further, if the second intermediate difference b is greater than or equal to the sum of the first preset time t1 and the second preset time t2 and less than the sum of twice the first preset time t1 and the second preset time t2, i.e. t1+t2≤t on -t0

[0063] Further, if the second intermediate difference b is greater than or equal to the sum of twice the first preset time t1 and the second preset time t2 and less than the sum of thrice the first preset time t1 and the second preset time t2, i.e. t1+2t2≤t on -t0

[0064] Further, if the second intermediate difference b is greater than or equal to the sum of thrice the first preset time t1 and the second preset time t2 and less than the sum of quadruple the first preset time t1 and the second preset time t2, i.e. t1+3t2≤t on -t0

[0065] Further, if the second intermediate difference b is greater than or equal to the sum of quadruple the first preset time t1 and the second preset time t2 and less than the sum of quintuple the first preset time t1 and the second preset time t2, i.e. t1+4t2≤t on -t0

[0066] Further, if the second intermediate difference b is greater than or equal to the sum of quintuple the first preset time t1 and the second preset time t2 and less than the sum of sextuple the first preset time t1 and the second preset time t2, i.e. t1+5t2≤t onWhen t0 < t1 + 6t2, the reference region identification bit T is the first region identification bit 1, and the first region identification bit indicates that the region where the protection action is located is the first reference region at the protection action moment.

[0067] S209, the integral of the instantaneous current data of each phase current in the target time period is calculated.

[0068] Specifically, according to the fault occurrence moment t f and the protection action moment t on , a target time period (t f , t on ) is established, the first instantaneous current data of the A-phase current, the B-phase current and the C-phase current in the target time period are obtained, the first instantaneous current data includes current instantaneous values at multiple moments, the instantaneous current data of each phase current is integrated to obtain the A-phase current integral S a , the B-phase current integral S b and the C-phase current integral S c , which are obtained by the following formula (1): (1); Wherein, i x ( t ) is the instantaneous value of each phase current such as i A ( t ), i B ( t ), i C ( t ) are the instantaneous values of the A-phase current, the B-phase current and the C-phase current on the AC side of the converter respectively.

[0069] S210, according to the protection action moment, a second measurement time period is established, and the maximum value of the current is calculated in the second measurement time period.

[0070] Specifically, according to the sum of the protection action moment t on and the third preset value m2 such as 25ms, and the sum of the protection action moment t on and the fourth preset value n2 such as 30ms, a second measurement time period (t on +m2, t on +n2) is established, wherein the third preset value such as 25ms is less than the fourth preset value such as 30ms, the third preset value such as 25ms is greater than the first preset value such as 20ms, and the third preset value such as 25ms is less than the second preset value such as 40ms.

[0071] Further, A-phase current, B-phase current and C-phase current in three-phase current are acquired as second instantaneous current data in a second measurement time period, the second instantaneous current data including current instantaneous values at multiple time points, and the current instantaneous value with the largest absolute value in the second instantaneous current data is taken as a current maximum value i ac , which is acquired by the following formula (2): (2); Wherein, i ac is the current maximum value, i A ( t ), i B ( t ), i C ( t ) are instantaneous values of A-phase current, B-phase current and C-phase current of the AC side of the converter respectively.

[0072] S211, if the current maximum value is less than a preset current threshold, it is detected whether the thyristor monitoring protection is in action.

[0073] Specifically, after acquiring the three-phase current characteristic information including the integral of each three-phase current and the current maximum value, it is detected whether the current maximum value i ac is less than a preset current threshold k set , such as 0.04pu, if not, that is, the current maximum value i ac is greater than or equal to the preset current threshold k se , it is confirmed that the target short-circuit fault position is the AC side of the converter.

[0074] Further, if yes, that is, the current maximum value i ac is less than the preset current threshold k se , it is further determined whether the thyristor monitoring protection is in action, and if the thyristor monitoring protection is not in action, it is confirmed that the target short-circuit fault position is the DC side of the converter.

[0075] S212, if yes, in the fault criterion database, the corresponding fault criterion is acquired according to the conduction identification bit as a target fault criterion, and the target fault criterion is realized based on the integral of each three-phase current to acquire the target short-circuit fault position.

[0076] Specifically, if the thyristor monitoring protection action is monitored, the target short-circuit fault position needs to be determined according to the on-state identification bit S and the integrals of the three-phase currents, that is, according to the on-state identification bit S, the same on-state identification bit is searched in the fault criterion database, the associated fault criterion is obtained according to the same on-state identification bit as the target fault criterion, and the judgment process of the target fault criterion is realized according to the integrals of the three-phase currents and the reference area identification bit obtained, so as to obtain the short-circuit fault of the converter valve as the target short-circuit fault position.

[0077] In the formula, the fault criterion database pre-stores a plurality of different on-state identification bits and fault criteria in association, the fault criterion includes a judgment logic chain about the integrals of the three-phase currents and the reference area identification bit, the judgment logic chain ends at the corresponding converter valve as the short-circuit fault position, and the fault criteria associated with different on-state identification bits are different.

[0078] The embodiment of the present application provides a converter short-circuit fault positioning method based on valve on-state, which obtains the on-state identification bit and the reference area identification bit of each converter valve in the converter through the protection action time indicating the valve short-circuit protection action and the fault occurrence time when the valve is short-circuited, establishes a target time period according to the fault occurrence time and the protection action time, calculates the three-phase current characteristic information of the alternating current side of the converter in the target time period, wherein the three-phase current characteristic information includes the integrals of the three-phase currents and the maximum value of the currents, and determines the target short-circuit fault position of each converter valve according to the on-state identification bit, the three-phase current characteristic information and the reference area identification bit, so as to improve the fault positioning accuracy and feasibility.

[0079] Embodiment 3 Further, the judgment process of the target fault criterion in the above S212 step is further illustrated, Figure 4 The flowchart of the fault criterion provided by the embodiment of the present application Figure 1 . Figure 5 The flowchart of the fault criterion provided by the embodiment of the present application Figure 2 .

[0080] In combination with Figure 4 As shown in the figure, when the on-state identification bit S is the fourth on-state identification number such as 4, the fourth on-state identification number indicates that at the fault occurrence time t f , the second converter valve V2 and the third converter valve V3 are in the on-state, the same on-state identification bit as the fourth on-state identification number is obtained in the fault criterion database, and the associated fault criterion is obtained according to the same on-state identification bit as the target fault criterion.

[0081] Further, based on the obtained target fault criterion, it is judged whether the A-phase current integral S a= 0; if yes, judge whether the on identification bit S = the reference area identification bit T is satisfied; if yes, the target short-circuit fault position is the converter valve V5, i.e. f 25 or the converter valve V6, i.e. f 26 ; if no, the target short-circuit fault position is the converter valve V5, i.e. f 25 .

[0082] Judge whether the A-phase current integral S a < 0 is satisfied; if no, the target short-circuit fault position is the converter valve V4, i.e. f 24 ; if yes, judge whether the C-phase current integral S c = 0 is satisfied; if yes, the target short-circuit fault position is the converter valve V1, i.e. f 21 ; if no, the target short-circuit fault position is the converter valve V6, i.e. f 26 .

[0083] As shown in Figure 5 , when the on identification bit S is the fifth on identification number such as 5, the fifth on identification number indicates that at the moment t f of the fault occurrence, the third converter valve V3 and the fourth converter valve V4 are in the on state, the on identification bit same as the fourth on identification number is acquired in the fault criterion database, and the associated fault criterion is acquired according to the same on identification bit as the target fault criterion.

[0084] Further, based on the acquired target fault criterion, judge whether the A-phase current integral S a < 0 is satisfied; if no, the target short-circuit fault position is the converter valve V5, i.e. f 25 ; if yes, judge whether the B-phase current integral S b = 0 is satisfied; if yes, the target short-circuit fault position is the converter valve V2, i.e. f 22 , if no, judge whether the C-phase current integral S c > 0 is satisfied; if yes, the target short-circuit fault position is the converter valve V1, i.e. f 21 , if no, judge whether the on identification bit S = the reference area identification bit T is satisfied; if no, the target short-circuit fault position is the converter valve V6, i.e. f 26 , if yes, the target short-circuit fault position is the converter valve V1, i.e. f 21 or the converter valve V6, i.e. f 26 .

[0085] The embodiment of the present application provides a method for locating a converter short-circuit fault based on the valve conduction state, which determines whether the fault occurs in the converter AC side area, valve body area or DC side area by the action of valve short-circuit protection and thyristor protection at different fault locations and the AC side three-phase current characteristics after the converter is locked, and determines the time when the fault occurs t f and protection action time t on The time interval with the starting time t0 determines the time when the fault occurs t f The conduction state of the converter valve and the time when the fault occurs t f The area S to which the moment belongs and the protection action time t on The time belongs to the area T, and whether the commutation process occurs is determined by judging whether S is equal to T. Further, according to the time when the fault occurs t f The conduction state of the converter valve at the current moment is calculated, and the three-phase current on the AC side of the converter is integrated to accurately locate the short-circuit fault of six thyristors of a six-pulse converter in the converter area, thereby improving the fault location accuracy and feasibility.

[0086] Figure 6 The short circuit simulation results provided in this embodiment are shown as follows Figure 1 . Figure 7 The short circuit simulation results provided in this embodiment are shown as follows Figure 2 .

[0087] Combine Figure 6 As shown, a short-circuit fault simulation is performed on the first converter valve V1. t =0.971s, a short circuit fault occurs in the first converter valve V1, and the fault lasts for 2s. At this time, the second converter valve V2 and the third converter valve V3 are in the on state. The simulation results are as follows: Figure 6 As shown, from Figure 6 (a) shows that the protection criterion characteristic quantity i diff exist t =0.971s, it starts to increase gradually from zero. t =0.975s, the valve short-circuit protection is activated, and the valve short-circuit protection action makes the converter locked after completion i ac Waveform Figure 6 As shown in (b), it can be seen that in (t on +25,t on +30) time period i ac Almost zero, that is, less than 0.04pu, and because it is a valve short circuit fault, the thyristor monitoring protection will also be activated. At the same time, the three-phase current on the AC side of the converter is (t f ,t on ) The integral results within the time period are as followsFigure 6 (c), it can be seen that the integral of phase A current S a <0, B phase current integral S b >0, C phase current integral S c =0, which satisfies the short-circuit fault location criterion of the first converter valve V1.

[0088] Combine Figure 7 As shown, a short-circuit fault simulation is performed on the sixth converter valve V6. t =0.6725s, a short circuit fault occurs in the sixth converter valve V6, and the fault lasts for 2s. At this time, the second converter valve V2 and the third converter valve V3 are in the on state, the second converter valve V2 is about to be closed, and the fourth converter valve V4 is in the on state. The second converter valve V2 switches to the second converter valve V4. The simulation results are as follows: Figure 7 As shown, from Figure 7 (a) shows that the protection criterion characteristic quantity i diff exist t =0.6725s, it starts to increase gradually from zero. t =0.674s, the valve short-circuit protection is activated, and the valve short-circuit protection action makes the converter locked after completion i ac Waveform Figure 7 As shown in (b), it can be seen that in (t on +25, t on +30) time period i ac Almost zero, that is, less than 0.04pu, and because it is a valve short circuit fault, the thyristor monitoring protection will also be activated. At the same time, the three-phase current on the AC side of the converter is (t f ,t on ) The integral results within the time period are as follows Figure 7 (c), it can be seen that the integral of phase A current S a <0, B phase current integral S b >0, C phase current integral S c <0, meeting the criterion for locating the short-circuit fault of the converter valve V6.

[0089] Figure 8 A schematic diagram of the structure of a converter short-circuit fault location device based on valve conduction state provided in an embodiment of the present application is shown in FIG. Figure 8 As shown, the apparatus 800 includes: The acquisition module 801 is configured to acquire a protection action time of a valve short-circuit protection action, acquire a characteristic quantity waveform at the time of valve short-circuit in the continuously recorded fault recording data, and identify a mutation time of the characteristic quantity waveform as a fault occurrence time; The first processing module 802 is configured to acquire a conduction identification bit and a reference region identification bit of each valve in the converter according to the fault occurrence time, wherein the conduction identification bit is used to indicate a valve in a conduction state at the fault occurrence time, and the reference region identification bit is used to indicate a region of the valve short-circuit protection action at the protection action time. The second processing module 803 is configured to establish a target time period according to the fault occurrence time and the protection action time, and calculate and acquire three-phase current characteristic information of the AC side of the converter in the target time period, wherein the three-phase current characteristic information includes an integral and a maximum value of each three-phase current. The positioning module 804 is configured to determine a target short-circuit fault position according to the conduction identification bit, the three-phase current characteristic information and the reference region identification bit.

[0090] Further, the first processing module 802 is specifically configured to establish a first measurement time period according to a difference between the fault occurrence time and a first preset value and a sum of the fault occurrence time and a second preset value, wherein the first preset value is smaller than the second preset value. In the fault recording data, A-phase current data of the AC side of the converter in the first measurement time period is called, and the A-phase current data includes A-phase current values at multiple different times. Based on the fault occurrence time, a preset number of A-phase current values that are continuously and sequentially increased from zero are acquired, and a time corresponding to a current value of zero is marked as a candidate occurrence time, so as to acquire multiple candidate occurrence times. Among the multiple candidate occurrence times, a candidate occurrence time closest to the fault occurrence time is taken as a reference occurrence time. A first intermediate difference value between the fault occurrence time and the reference occurrence time is acquired, the first intermediate difference value is compared with a preset reference time to acquire a first comparison result, and the conduction identification bit is acquired according to the first comparison result. A second intermediate difference value between the protection action time and the reference occurrence time is acquired, the second intermediate difference value is compared with the preset reference time to acquire a second comparison result, and the reference region identification bit is acquired according to the second comparison result; wherein the preset reference time includes a first preset time and a second preset time, and the first preset time is smaller than the second preset time.

[0091] Further, the first processing module 802 is specifically configured to, if the first comparison result indicates that the first intermediate difference value is less than the first preset time, the conduction identification bit is a first conduction identification number, and the first conduction identification number indicates that the fifth converter valve and the sixth converter valve are in the conduction state at the fault occurrence moment. If the first intermediate difference value is greater than or equal to the first preset time and less than the sum of the first preset time and the second preset time, the conduction identification bit is a second conduction identification number, and the second conduction identification number indicates that the first converter valve and the sixth converter valve are in the conduction state at the fault occurrence moment. If the first intermediate difference value is greater than or equal to the sum of the first preset time and the second preset time and less than the sum of twice the first preset time and the second preset time, the conduction identification bit is a third conduction identification number, and the third conduction identification number indicates that the first converter valve and the second converter valve are in the conduction state at the fault occurrence moment. If the first intermediate difference value is greater than or equal to the sum of twice the first preset time and the second preset time and less than the sum of thrice the first preset time and the second preset time, the conduction identification bit is a fourth conduction identification number, and the fourth conduction identification number indicates that the second converter valve and the third converter valve are in the conduction state at the fault occurrence moment. If the first intermediate difference value is greater than or equal to the sum of thrice the first preset time and the second preset time and less than the sum of quadruple the first preset time and the second preset time, the conduction identification bit is a fifth conduction identification number, and the fifth conduction identification number indicates that the third converter valve and the fourth converter valve are in the conduction state at the fault occurrence moment. If the first intermediate difference value is greater than or equal to the sum of quadruple the first preset time and the second preset time and less than the sum of quintuple the first preset time and the second preset time, the conduction identification bit is a sixth conduction identification number, and the sixth conduction identification number indicates that the fourth converter valve and the fifth converter valve are in the conduction state at the fault occurrence moment. If the first intermediate difference value is greater than or equal to the sum of quintuple the first preset time and the second preset time and less than the sum of sextuple the first preset time and the second preset time, the conduction identification bit is the first conduction identification number, and the first conduction identification number indicates that the fifth converter valve and the sixth converter valve are in the conduction state at the fault occurrence moment.

[0092] Further, the second processing module 803 is specifically configured to, if the second comparison result indicates that the second intermediate difference value is less than the first preset time, the reference region identifier is a first region identifier, and the first region identifier indicates that the region where the protection action is located at the protection action moment is a first reference region. If the second intermediate difference value is greater than or equal to the sum of the first preset time and the second preset time, and less than the sum of the first preset time and twice the second preset time, the reference region identifier is a third region identifier, and the third region identifier indicates that the region where the protection action is located at the protection action moment is a third reference region. If the second intermediate difference value is greater than or equal to the sum of the first preset time and the second preset time, and less than the sum of the first preset time and twice the second preset time, the reference region identifier is a third region identifier, and the third region identifier indicates that the region where the protection action is located at the protection action moment is a third reference region. If the second intermediate difference value is greater than or equal to the sum of the first preset time and the second preset time, and less than the sum of the first preset time and twice the second preset time, the reference region identifier is a third region identifier, and the third region identifier indicates that the region where the protection action is located at the protection action moment is a third reference region. If the second intermediate difference value is greater than or equal to the sum of the first preset time and the second preset time, and less than the sum of the first preset time and twice the second preset time, the reference region identifier is a third region identifier, and the third region identifier indicates that the region where the protection action is located at the protection action moment is a third reference region. If the second intermediate difference value is greater than or equal to the sum of the first preset time and the second preset time, and less than the sum of the first preset time and twice the second preset time, the reference region identifier is a third region identifier, and the third region identifier indicates that the region where the protection action is located at the protection action moment is a third reference region. If the second intermediate difference value is greater than or equal to the sum of the first preset time and the second preset time, and less than the sum of the first preset time and twice the second preset time, the reference region identifier is a third region identifier, and the third region identifier indicates that the region where the protection action is located at the protection action moment is a third reference region.

[0093] Further, the second processing module 803 is specifically configured to acquire A-phase current, B-phase current and C-phase current in the three-phase current, and first instantaneous current data of the target time period, the first instantaneous current data including current instantaneous values at multiple moments. the target time period to obtain an A-phase current integral, a B-phase current integral, and a C-phase current integral; a second measurement time period is established according to the protection action time point, and the current maximum value is calculated in the second measurement time period.

[0094] Further, the positioning module 804 is specifically configured to: if the current maximum value is greater than or equal to the current threshold value, the target short-circuit fault position is the AC side of the converter; if the current maximum value is less than the preset current threshold value, it is detected whether the thyristor monitoring protection is in action; if not, the target short-circuit fault position is the DC side of the converter; if yes, the target short-circuit fault position is determined according to the conduction identification bit and the integrals of the three-phase currents.

[0095] Further, the positioning module 804 is specifically configured to: in a fault criterion database, a corresponding fault criterion is obtained according to the conduction identification bit as a target fault criterion, and the target fault criterion is implemented based on the integrals of the three-phase currents to obtain the target short-circuit fault position. The fault criterion database pre-stores a plurality of groups of different conduction identification bits and fault criteria, the fault criterion includes a judgment logic chain about the integrals of the three-phase currents and the reference region identification bit, and the judgment logic chain points to a corresponding converter valve at the end as the short-circuit fault position.

[0096] The application also provides a computer-readable storage medium, which stores computer execution instructions, and when a processor executes the computer execution instructions, the valve conduction state-based converter short-circuit fault positioning method is implemented.

[0097] The computer-readable storage medium described above can be implemented by any type of volatile or non-volatile storage device or a combination thereof, such as static random access memory (SRAM), electrically erasable programmable read-only memory (EEPROM), erasable programmable read-only memory (EPROM), programmable read-only memory (PROM), read-only memory (ROM), magnetic memory, flash memory, magnetic disk or optical disk. The readable storage medium can be any available medium that can be accessed by a general-purpose or special-purpose computer.

[0098] The above detailed description further describes the purpose, technical solutions and beneficial effects of the application, and it should be understood that the above description is only a specific embodiment of the application and is not used to limit the protection scope of the application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the application shall be included in the protection scope of the application.

Claims

1. A method for locating a converter short-circuit fault based on valve conduction status, characterized in that: include: Get the protection action time of the valve short circuit protection action; In the continuously recorded fault recording data, a characteristic waveform when the valve is short-circuited is obtained, and a sudden change time of the characteristic waveform is identified as the time of fault occurrence; acquiring a conduction flag and a reference area flag of each converter valve in the converter according to the moment of the fault occurrence, wherein the conduction flag is used to indicate the converter valve that is in the conduction state at the moment of the fault occurrence, and the reference area flag is used to indicate the area where the valve short-circuit protection is actuated at the moment of the protection action; Establishing a target time period according to the fault occurrence time and the protection action time; Within the target time period, calculating and obtaining three-phase current characteristic information on the AC side of the converter, wherein the three-phase current characteristic information includes the integral of each three-phase current and the current maximum value; A target short-circuit fault location is determined according to the conduction identification bit, the three-phase current characteristic information, and the reference area identification bit.

2. The method for locating a converter short-circuit fault based on valve conduction state according to claim 1, characterized in that: The obtaining of the conduction flag and the reference area flag of each converter valve in the converter according to the fault occurrence time includes: Establishing a first measurement time period according to a difference between the fault occurrence moment and a first preset value, and a sum of the fault occurrence moment and a second preset value, wherein the first preset value is less than the second preset value; Retrieving the A-phase current data of the AC side of the converter in the first measurement time period from the fault recording data, the A-phase current data including the A-phase current values ​​at multiple different moments; Based on the fault occurrence moment, obtaining a preset number of the A-phase current values ​​that increase successively starting from zero, and marking the moment corresponding to the current value being zero as the candidate occurrence moment, to obtain a plurality of the candidate occurrence moments; Among the multiple candidate occurrence moments, the candidate occurrence moment closest to the fault occurrence moment is used as a reference occurrence moment; Obtaining a first intermediate difference between the fault occurrence time and the reference occurrence time, comparing the first intermediate difference with a preset reference time to obtain a first comparison result, and obtaining the conduction flag according to the first comparison result; Obtaining a second intermediate difference between the protection action moment and the reference occurrence moment, comparing the second intermediate difference with the preset reference time to obtain a second comparison result, and obtaining the reference area identification bit according to the second comparison result; The preset reference time includes a first preset time and a second preset time, and the first preset time is smaller than the second preset time.

3. The method for locating a converter short-circuit fault based on valve conduction state according to claim 2, characterized in that: The acquiring the conduction flag according to the first comparison result includes: If the first comparison result indicates that the first intermediate difference is less than the first preset time, the conduction flag is a first conduction flag number, and the first conduction flag number indicates that the fifth converter valve and the sixth converter valve are in a conducting state at the time when the fault occurs; If the first intermediate difference is greater than or equal to the first preset time and less than the sum of the first preset time and the second preset time, the conduction flag is a second conduction flag number, and the second conduction flag number indicates that the first converter valve and the sixth converter valve are in a conducting state at the time when the fault occurs; If the first intermediate difference is greater than or equal to the sum of the first preset time and the second preset time, and less than the sum of the first preset time and twice the second preset time, the conduction flag is a third conduction flag number, and the third conduction flag number indicates that the first converter valve and the second converter valve are in a conducting state at the time when the fault occurs; If the first intermediate difference is greater than or equal to the sum of the first preset time and twice the second preset time, and less than the sum of the first preset time and three times the second preset time, the conduction flag is a fourth conduction flag number, and the fourth conduction flag number indicates that the second converter valve and the third converter valve are in a conducting state at the time when the fault occurs; If the first intermediate difference is greater than or equal to the sum of the first preset time and three times the second preset time, and less than the sum of the first preset time and four times the second preset time, the conduction flag is a fifth conduction flag number, and the fifth conduction flag number indicates that the third converter valve and the fourth converter valve are in a conducting state at the time when the fault occurs; If the first intermediate difference is greater than or equal to the sum of the first preset time and four times the second preset time, and less than the sum of the first preset time and five times the second preset time, the conduction flag is a sixth conduction flag number, and the sixth conduction flag number indicates that the fourth converter valve and the fifth converter valve are in a conducting state at the time of the fault occurrence; If the first intermediate difference is greater than or equal to the sum of five times the first preset time and the second preset time, and less than the sum of six times the first preset time and the second preset time, the conduction flag is a first conduction flag number, and the first conduction flag number indicates that at the moment the fault occurs, the fifth converter valve and the sixth converter valve are in the conduction state.

4. The method for locating a converter short-circuit fault based on valve conduction state according to claim 2, characterized in that: The obtaining the reference area identification bit according to the second comparison result includes: If the second comparison result indicates that the second intermediate difference is less than the first preset time, the reference area identification bit is the first area identification bit, and the first area identification bit indicates that at the protection action moment, the area where the protection action is located is the first reference area; If the second intermediate difference is greater than or equal to the first preset time and less than the sum of the first preset time and the second preset time, the reference area identification bit is the second area identification bit, and the second area identification bit indicates that at the protection action moment, the area where the protection action is located is the second reference area; If the second intermediate difference is greater than or equal to the sum of the first preset time and the second preset time, and less than the sum of the first preset time and twice the second preset time, the reference area identification bit is the third area identification bit, and the third area identification bit indicates that at the protection action moment, the area where the protection action is located is the third reference area; If the second intermediate difference is greater than or equal to the sum of the first preset time and twice the second preset time, and less than the sum of the first preset time and three times the second preset time, the reference area identification bit is the fourth area identification bit, and the fourth area identification bit indicates that at the protection action moment, the area where the protection action is located is the fourth reference area; If the second intermediate difference is greater than or equal to the sum of the first preset time and three times the second preset time, and less than the sum of the first preset time and four times the second preset time, the reference area identification bit is the fifth area identification bit, and the fifth area identification bit indicates that at the protection action moment, the area where the protection action is located is the fifth reference area; If the second intermediate difference is greater than or equal to the sum of the first preset time and four times the second preset time, and less than the sum of the first preset time and five times the second preset time, the reference area identification bit is the sixth area identification bit, and the sixth area identification bit indicates that at the protection action moment, the area where the protection action is located is the sixth reference area; If the second intermediate difference is greater than or equal to the sum of five times the first preset time and the second preset time, and less than the sum of six times the first preset time and the second preset time, the reference area identification bit is the first area identification bit, and the first area identification bit indicates that at the moment of the protection action, the area where the protection action is located is the first reference area.

5. The method for locating a converter short-circuit fault based on valve conduction state according to claim 1, characterized in that: The calculating and obtaining the three-phase current characteristic information on the AC side of the converter within the target time period includes: Acquire first instantaneous current data of phase A current, phase B current, and phase C current in the three-phase current within the target time period, wherein the first instantaneous current data includes instantaneous current values ​​at multiple moments; Calculate and obtain the integral of the instantaneous current data of each phase current within the target time period to obtain the A-phase current integral, the B-phase current integral, and the C-phase current integral; A second measurement time period is established according to the protection action moment, and the maximum current value is calculated and obtained within the second measurement time period.

6. The method for locating a converter short-circuit fault based on valve conduction state according to claim 5, characterized in that: The step of establishing a second measurement time period according to the protection action time, and calculating and obtaining the maximum current value within the second measurement time period, includes: establishing the second measurement time period according to the sum of the protection action time and a third preset value, and the sum of the protection action time and a fourth preset value, wherein the third preset value is less than the fourth preset value, the third preset value is greater than the first preset value, and the third preset value is less than the second preset value; Obtain the second instantaneous current data of phase A, phase B and phase C in the three-phase current in the second measurement time period, wherein the second instantaneous current data includes instantaneous current values ​​at multiple moments, and the instantaneous current value with the largest absolute value in the second instantaneous current data is used as the maximum current value.

7. The method for locating a converter short-circuit fault based on valve conduction state according to any one of claims 1 to 6, characterized in that: The determining of a target short-circuit fault location according to the conduction flag, the three-phase current characteristic information, and the reference area flag includes: If the maximum current is greater than or equal to the current threshold, the target short-circuit fault location is the AC side of the converter; If the maximum current is less than the preset current threshold, detecting whether the thyristor monitoring protection is actuated; If not, the target short-circuit fault location is the DC side of the converter; If so, the target short-circuit fault position is determined according to the conduction flag and the integral of the three-phase currents.

8. The method for locating a converter short-circuit fault based on valve conduction state according to claim 7, characterized in that: The determining the target short-circuit fault position according to the conduction flag and the integral of each three-phase current includes: In a fault criterion database, a corresponding fault criterion is obtained according to the conduction flag, and used as a target fault criterion. The target fault criterion is implemented based on the integration of the three-phase currents to obtain the target short-circuit fault location. Among them, the fault judgment database pre-associately stores multiple groups of different conduction identification bits and the fault judgment criteria, and the fault judgment criteria include a judgment logic chain about the integral of each three-phase current and the reference area identification bit, and the end of the judgment logic chain points to the corresponding converter valve as the short-circuit fault location.

9. A converter short-circuit fault location device based on valve conduction state, characterized in that: include: An acquisition module is used to obtain the protection action time of the valve short-circuit protection action, obtain the characteristic waveform when the valve is short-circuited from the continuously recorded fault recording data, and identify the sudden change time of the characteristic waveform as the fault occurrence time; a first processing module, configured to obtain, based on the moment of the fault occurrence, a conduction flag and a reference region flag of each converter valve in the converter, wherein the conduction flag indicates a converter valve that is in a conduction state at the moment of the fault occurrence, and the reference region flag indicates a region where valve short-circuit protection is actuated at the moment of the protection action; a second processing module, configured to establish a target time period according to the fault occurrence time and the protection action time, and calculate and obtain three-phase current characteristic information on the AC side of the converter within the target time period, wherein the three-phase current characteristic information includes the integral of each three-phase current and the current maximum value; A positioning module is used to determine a target short-circuit fault location based on the conduction identification bit, the three-phase current characteristic information and the reference area identification bit.

10. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by a processor, the method according to any one of claims 1 to 8 is implemented.

Images