A method for selecting a small current grounding line for power supply in a hydropower station

Abstract

The invention discloses a small current grounding line selection method for power plant use in a hydropower station, and relates to the technical field of grounding line selection, including: obtaining a line fault direction based on a detection result of a signal sensor; obtaining an environmental interference point; obtaining an environmental impact voltage in the line fault direction and a line selection fault line, and detecting the voltage of a grounding point of the line selection fault line; and obtaining a most preferred line circuit in a non-fault line based on an analysis result. The invention is used to solve the problem in the existing method for small current grounding line selection that when a line exposed to the environment is selected for fault line selection, the fault area is greatly affected by the weather, and only by staggering arc extinguishing coils to compensate for residual current, the small current grounding line selection will still be misjudged, thereby causing the problem of misselection and missed selection.

Description

Technical Field

[0001] The invention relates to the technical field of grounding line selection, and in particular to a small current grounding line selection method for power supply of a hydropower station. Background Art

[0002] The full name of small current line selection is small current grounding line selection device, referred to as small current. It is a protection device used in the power industry; the device is suitable for single-phase grounding line selection in 3KV-66KV neutral point ungrounded or neutral point grounded through resistors and arc suppression coils. It is used in power substations, power plants, hydropower stations and power supply systems of large factories and mines such as chemical, oil production, metallurgy, coal and railways in the power system. It can indicate the line where a single-phase grounding fault occurs; small current grounding line selection is a method to reduce ground current. By directly grounding the power supply or grounding it through a small resistance grounding wire, avoid selecting lines with large conduction current when selecting lines, thereby reducing ground current.

[0003] Existing methods for small current grounding line selection usually add voltage relays and time relays, connect the voltage relay coil to the open triangle voltage signal output end of the bus voltage transformer, and connect the normally open contact of the time relay in series between the signal input end of the small current grounding line selection device and the open triangle voltage signal output end of the bus voltage transformer, so as to perform fault line selection after the arc suppression coil compensation residual current is stable, thereby improving the correctness of the operation of the small current grounding line selection device. Although this method can stagger the arc suppression coil compensation residual current and prevent misjudgment caused by the influence of the arc suppression coil compensation residual current, there are weather influences when performing fault line selection. For example, there are lines exposed to the environment when hydropower plants use electricity and supply electricity, and when performing fault line selection, the fault area is greatly affected by the weather. Only by staggering the arc suppression coil compensation residual current, it will still lead to misjudgment of small current grounding line selection. The small current grounding line selection protection system of the power grid neutral point ungrounded system is disclosed in the patent application with the publication number CN106329509A. The scheme is to stagger the dynamic compensation process of the adjustable arc extinguishing coil and the process of capturing the grounding fault by the small current grounding line selection, so that the small current grounding line selection device can select the fault line after the residual current of the arc extinguishing coil compensation is stable, thereby improving the correctness of the operation of the small current grounding line selection device. Other improvements for small current fault line selection are usually to increase the line selection line to improve the reliability of the line selection. However, this improvement method still cannot solve the problem that when the fault area is greatly affected by the weather during fault line selection, the small current grounding line selection will be misjudged, thereby causing the problem of misselection and missed selection. In view of this, it is necessary to improve the existing method for small current grounding line selection. Summary of the invention

[0004] The present invention aims to solve at least one of the technical problems in the prior art to a certain extent. By proposing a small current grounding line selection method for hydropower station power plant, it is used to solve the problem that when fault line selection is performed on lines exposed to the environment, the fault area is greatly affected by the weather. Only by staggering the arc suppression coils to compensate for the residual current, the small current grounding line selection will still be misjudged, thereby causing the problem of misselection and missed selection.

[0005] To achieve the above objectives, in a first aspect, the present application provides a low-current grounding line selection method for power supply of a hydropower station, comprising the following steps:

[0006] A signal sensor is set in the grounding line of the line. When a grounding fault occurs in the line, the line fault direction is obtained based on the detection result of the signal sensor; the environment in the line fault direction is obtained based on the map, and the environment is analyzed to obtain the environmental interference point; the environmental impact voltage in the line fault direction is obtained based on the environmental interference point;

[0007] Based on the environmental impact voltage, the line in the line fault direction is analyzed and the selected fault line is obtained, the voltage of the grounding point of the selected fault line is detected, and the detection result is recorded as the fault voltage;

[0008] The fault voltage is analyzed, and based on the analysis result, the fault circuit and the non-fault circuit in the selected fault line are obtained, the non-fault circuit is screened, and based on the screening result, the most preferred line circuit in the non-fault line is obtained.

[0009] Furthermore, when a ground fault occurs in the line, obtaining the line fault direction based on the detection result of the signal sensor includes:

[0010] Step S101: Record multiple grounding lines as current grounding lines JD1 to JD n ; placing a signal sensor in each current grounding line JD, wherein the signal sensor is used to monitor the current in the current grounding line JD;

[0011] Establish a plane rectangular coordinate system, recorded as the stable monitoring coordinate system, where the unit of the X-axis of the stable monitoring coordinate system is time, and the unit of the Y-axis is current; for any current grounding line JD n1 , based on the current grounding line JD n1 The signal sensor in the ground line obtains the current JD in the last day n1 The current in the stable monitoring coordinate system is plotted, and the corresponding curve is recorded as the rated current curve EQn1;

[0012] Get the rated current curve EQ corresponding to all current grounding lines JD.

[0013] Furthermore, when a ground fault occurs in the line, obtaining the line fault direction based on the detection result of the signal sensor also includes:

[0014] For any current grounding line JD n1 , based on the signal sensor to obtain the current grounding line JD n1 The current in the recent k days without faults is plotted, and the rated current curve EQ corresponding to each day is drawn in the stable monitoring coordinate system, which are recorded as fitting current curves NH1 to NH k ; In the stable monitoring coordinate system, the fitting current curve NH1 is changed to the fitting current curve NH k Fitted into a curve and recorded as the rated reference curve EC n1 ;

[0015] For any point α(x0, y0) in the rated reference curve ECn1, the point with the horizontal coordinate x0 in the rated current curve EQn1 is recorded as β(x0, y1); the absolute value of the difference between y1 and y0 is recorded as the rated difference; the rated differences of all points in the rated reference curve ECn1 are obtained, and the maximum value of all rated differences is recorded as the fault reference difference.

[0016] Furthermore, when a ground fault occurs in the line, the line fault direction is obtained based on the detection result of the signal sensor, the environment is analyzed to obtain the environmental interference point, and the environmental impact voltage of the line fault direction is obtained based on the environmental interference point, which also includes:

[0017] Get the fault reference difference corresponding to all current grounding lines JD; for any current grounding line JD n1 , based on the signal sensor to obtain the current grounding line JD in real time n1 The current in the stable monitoring coordinate system is marked in real time as the real-time current point; the horizontal coordinate of the real-time current point is marked as x1. When |y2-y3| is greater than the current grounding line JD at any time n1 When the fault reference value is reached, the circuit grounding line JD n1 The direction is recorded as the line fault direction, where y2 is the ordinate of the real-time current point, and y3 is the ordinate of the point with the abscissa x1 in the rated current curve EQn1;

[0018] When a line fault direction appears, all circuits in the line fault direction are recorded as fault lines; the areas affected by all fault lines are recorded as fault areas in the map;

[0019] The weather in the fault area is recorded as environmental impact weather. Based on the distribution data of the fault line in the fault area, the potential difference analysis method is used to obtain the environmental interference points and environmental impact voltage in the fault line after the environmental impact weather affects the fault line, wherein the distribution data includes the distribution position of the line in the fault area and the exposure condition of the fault line.

[0020] Furthermore, the potential difference analysis method includes: recording the length of the line as the total length of the line, recording the length of the line exposed to the air as the total exposed length, and recording (total exposed length\total line length)×100% as the exposed ratio; obtaining the total length of the line and the total exposed length of the fault area based on the distribution data of the fault line, respectively recording them as the total length of the fault line and the total length of the fault exposed, and recording the exposed ratio obtained from the total length of the fault line and the total length of the fault exposed as the fault exposed ratio; simulating the impact of the environment on the weather in a meteorological environment simulation laboratory, and placing a line with a length of the total length of the line in the meteorological environment simulation laboratory, recorded as a simulated circuit; obtaining the voltage between all positions in the simulated circuit and the grounding point of the simulated circuit when the exposure ratio is 0 to 100%, and recording the recorded data as environmental simulation data.

[0021] Furthermore, the potential difference analysis method also includes:

[0022] Obtain data in which the exposed ratio is the fault exposed ratio in the environmental simulation data, and record it as the fault simulation data; obtain the voltage between all positions in the fault line and the grounding point of the fault line, and record it as the actual fault voltage. When the actual fault voltage at any position is not equal to the voltage at the same position in the fault simulation data, record the position as the environmental interference point, and record the voltage between the environmental interference point and the grounding point of the fault circuit as the environmental influence voltage;

[0023] Obtain all environmental interference points and environmental impact voltages in the fault line.

[0024] Further, based on the environmental impact voltage, the line in the line fault direction is analyzed and the selected fault line is obtained, the voltage of the grounding point of the selected fault line is detected, and the detection result is recorded as the fault voltage, including:

[0025] For any environmental interference point, all lines from the environmental interference point to the grounding point of the fault line are recorded as branch lines of the environmental interference point, the current in each branch line is obtained respectively, and the branch line with a current less than the rated current is recorded as the selected fault line;

[0026] The selected fault lines corresponding to all environmental interference points are obtained, and the voltage in the selected fault line is recorded as the fault voltage.

[0027] Further, analyzing the fault voltage, and obtaining the fault circuit and the non-fault circuit in the selected fault line based on the analysis result, screening the non-fault circuit, and obtaining the most preferred line circuit in the non-fault line based on the screening result includes:

[0028] For any selected fault line, all circuits in the selected fault line are recorded as circuits to be analyzed DL1 to circuits to be analyzed DL q , use the current proportion algorithm to obtain the current proportion corresponding to each circuit DL to be analyzed, and the current proportion algorithm includes: Where G is the current ratio, I e is the rated current of the circuit DL to be analyzed, I s is the actual current of the circuit DL to be analyzed, I sum It is the rated current of the selected fault line where the circuit to be analyzed is located.

[0029] Further, the fault voltage is analyzed, and based on the analysis result, the fault circuit and the non-fault circuit in the selected fault line are obtained, and the non-fault circuit is screened, which further includes:

[0030] The circuit DL to be analyzed with the largest current ratio among all the circuits to be analyzed DL is recorded as a fault circuit, and the circuits to be analyzed other than the fault circuit are recorded as non-fault circuits;

[0031] For any non-fault circuit, a plane rectangular coordinate system is established, which is recorded as the position screening coordinate system, wherein the units of the X-axis and the Y-axis of the position screening coordinate system are both in meters; based on the positional relationship between the non-fault circuit and the faulty circuit in the map, the non-fault circuit and the faulty circuit are drawn in the position screening coordinate system, and the maximum and minimum values ​​of the distance between the non-fault circuit and the faulty circuit are obtained, which are recorded as the maximum line selection distance and the minimum line selection distance, respectively; the value of the maximum line selection distance minus the minimum line selection distance is recorded as the distance difference; the distance differences corresponding to all non-fault circuits are obtained, and the non-fault circuit corresponding to the minimum distance difference is recorded as the optimal line selection circuit.

[0032] Further, obtaining the most preferred line circuit in the non-fault line based on the screening result includes:

[0033] The maximum current that can flow into the most preferred line circuit is recorded as the selected line maximum current; the current supply to the selected line fault line is cut off, and the circuit supply of the most preferred line circuit is increased until the current in the most preferred line circuit is the selected line maximum current.

[0034] Beneficial effects of the present invention: the present invention first sets a signal sensor in the grounding line of the line. When a grounding fault occurs in the line, the line fault direction is obtained based on the detection result of the signal sensor; the environment in the line fault direction is obtained based on the map, and the environment is analyzed to obtain the environmental interference point; the environmental impact voltage in the line fault direction is obtained based on the environmental interference point. The advantage of this is that by obtaining the environmental interference point based on the environment in the line fault direction, the point where the fault still exists under the influence of environmental factors in the line with the fault can be obtained, thereby preventing the misjudgment problem caused by the greater influence of the weather in the fault area during the grounding line selection process, thereby improving the accuracy and success rate of line selection;

[0035] The present invention also analyzes the line in the direction of the line fault based on the environmental impact voltage and obtains the line selection fault line, and detects the voltage of the grounding point of the line selection fault line; analyzes the fault voltage, and obtains the fault circuit and the non-fault circuit in the line selection fault line based on the analysis result and obtains the most preferred line circuit in the non-fault line. The advantage of this is that by detecting the voltage of the grounding point of the line selection fault line and analyzing the fault voltage, the circuit with fault in the fault line can be obtained, thereby further improving the circuit cut off during grounding line selection as the circuit with fault. At the same time, by selecting the most preferred line circuit in the non-fault line, the circuit most suitable for replacing the fault circuit can be effectively obtained, thereby reducing the impact of the fault circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 is a flow chart of the steps of the method of the present invention;

[0037] Figure 2 is a schematic diagram of a rated current curve EQ of the present invention;

[0038] Figure 3 It is a schematic diagram of the position of the real-time current point of the present invention;

[0039] Figure 4 It is a schematic structural diagram of the electronic device of the present invention. DETAILED DESCRIPTION

[0040] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the 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.

[0041] Example 1, first aspect, please refer to Figure 1As shown, the present application provides a low-current grounding line selection method for power supply of a hydropower station, comprising the following steps:

[0042] Step S1, setting a signal sensor in the grounding line of the line, when a grounding fault occurs in the line, obtaining the line fault direction based on the detection result of the signal sensor; obtaining the environment in the line fault direction based on a map, and analyzing the environment to obtain the environmental interference point; obtaining the environmental impact voltage in the line fault direction based on the environmental interference point;

[0043] Step S1 includes the following sub-steps: Step S101, multiple grounding lines are recorded as current grounding lines JD1 to JD2 respectively. n ; A signal sensor is placed in each current grounding line JD, wherein the signal sensor is used to monitor the current in the current grounding line JD; in a specific real-time process, the distinction of the current grounding line JD can be determined according to the distribution of the lines in actual conditions, such as according to the extension direction of the lines, multiple grounding lines can be recorded as current grounding lines JD1 to current grounding lines JD4 in the east, south, west and north directions;

[0044] Step S102, establish a plane rectangular coordinate system, recorded as a stable monitoring coordinate system, wherein the unit of the X-axis of the stable monitoring coordinate system is time, and the unit of the Y-axis is current; for any current grounding line JD n1 , based on the current grounding line JD n1 The signal sensor in the ground line obtains the current JD in the last day n1 The current in the stable monitoring coordinate system is plotted, and the corresponding curve is recorded as the rated current curve EQ n1 ; In the specific implementation process, the stable monitoring coordinate system can be used to obtain the current in the current grounding line JD when no fault occurs, so as to effectively detect the subsequent faults and improve the accuracy of the detection; for example, in a data processing process, the stable monitoring coordinate system obtained can be found in Figure 2 As shown, wherein the curve EQ is the rated current curve EQ;

[0045] Obtain the rated current curve EQ corresponding to all current grounding circuits JD;

[0046] Step S103: for any current grounding line JD n1 , based on the signal sensor to obtain the current grounding line JD n1 The current in the recent k days without faults is plotted, and the rated current curve EQ corresponding to each day is drawn in the stable monitoring coordinate system, which are recorded as fitting current curves NH1 to NH k ; In the stable monitoring coordinate system, the fitting current curve NH1 is changed to the fitting current curve NHk Fitted into a curve and recorded as the rated reference curve EC n1 In the specific implementation process, the value of k can be set according to the current data that can be actually obtained, such as only storing the current grounding line JD in the past ten days in the database n1 If the current data is obtained, the value of k can be set to any positive integer less than or equal to 10; by obtaining the rated reference curve EC, the approximate data of the current in each current grounding line JD in one day can be obtained, and by subsequently analyzing the rated reference curve EC and the rated current curve EQ, the fault reference difference for fault judgment during fault detection can be obtained, thereby ensuring that subsequent fault detection is more accurate;

[0047] Step S104: for the rated reference curve EC n1 For any point α(x0, y0) in the n1 The point with the inner horizontal coordinate x0 is recorded as β(x0, y1); the absolute value of the difference between y1 and y0 is recorded as the rated difference; the rated differences of all points in the rated reference curve ECn1 are obtained, and the maximum value of all the rated differences is recorded as the fault reference difference; in the specific implementation process, for example, when the interval formed by the rated differences of all points obtained in one data processing is [1A, 3A], the fault reference difference is 3A;

[0048] Step S104, obtaining the fault reference difference values ​​corresponding to all current grounding lines JD; for any current grounding line JD n1 , based on the signal sensor to obtain the current grounding line JD in real time n1 The current in the stable monitoring coordinate system is marked in real time as the real-time current point; the horizontal coordinate of the real-time current point is marked as x1. When |y2-y3| is greater than the current grounding line JD at any time n1 When the fault reference value is reached, the circuit grounding line JD n1 The direction is recorded as the line fault direction, where y2 is the ordinate of the real-time current point, and y3 is the rated current curve EQ n1 The ordinate of the point whose abscissa is x1; in a specific implementation process, for example, in a data processing process, the rated current curve EQ obtained is Figure 2 The curve EQ shown, the fault reference difference of the circuit grounding line JD is 3A, and the direction of the circuit grounding line JD is the north direction. The real-time current point obtained in real time is marked in the stable monitoring coordinate system. Figure 3As shown, point AA is the real-time current point, and the coordinate of point AA is (12:00, 6A). At this time, the horizontal coordinate of the curve EQ is 12:00, and the vertical coordinate of point BB is 2A. If |y2-y3| is greater than the fault reference value of the current grounding line JD, the north direction is recorded as the line fault direction;

[0049] Step S105, when a line fault direction appears, all circuits in the line fault direction are recorded as faulty lines; and the areas affected by all faulty lines are recorded as faulty areas in the map;

[0050] Step S106, recording the weather in the fault area as environmentally affected weather; using a potential difference analysis method based on the distribution data of the fault line in the fault area to obtain the environmental interference point and the environmentally affected voltage in the fault line after the environmentally affected weather affects the fault line, wherein the distribution data includes the distribution position of the line in the fault area and the exposure condition of the fault line;

[0051] Step S1061, the potential difference analysis method includes: recording the length of the line as the total length of the line, recording the length of the line exposed to the air as the total exposed length, and recording (total exposed length\total line length)×100% as the exposed ratio; obtaining the total length of the line and the total exposed length of the fault area based on the distribution data of the fault line, recording them as the total length of the fault line and the total exposed length of the fault, respectively, and recording the exposed ratio obtained from the total length of the fault line and the total exposed length of the fault as the fault exposed ratio; Step S1062, simulating the environmental impact of the weather in a meteorological environment simulation laboratory, and placing a line with a length of the total length of the line in the meteorological environment simulation laboratory, recorded as a simulated circuit; obtaining the voltage between all positions in the simulated circuit and the grounding point of the simulated circuit when the exposed ratio is 0 to 100%, and recording the recorded data as environmental simulation data; in the specific implementation process, for example, if the total length of the line is 1000m and the length of the line exposed to the air is 200m, the exposed ratio can be obtained by calculation as 20%;

[0052] Step S107, obtaining data of the exposed ratio being the fault exposed ratio in the environmental simulation data, and recording it as the fault simulation data; obtaining the voltage between all positions in the fault line and the grounding point of the fault line, and recording it as the actual fault voltage; when the actual fault voltage at any position is not equal to the voltage at the same position in the fault simulation data, the position is recorded as the environmental interference point, and the voltage between the environmental interference point and the grounding point of the fault circuit is recorded as the environmental influence voltage; in actual situations, the line exposed to the air may be affected by weather such as thunderstorms, strong winds and hail, resulting in the circuit data in the line being different from the conventional circuit data By obtaining the data of the exposed ratio as the fault exposed ratio in the environmental simulation data and obtaining the actual fault voltage, the voltage that should exist in the line under the influence of weather can be obtained. By recording the position where the actual fault voltage at any position is not equal to the voltage at the same position in the fault simulation data as the environmental interference point, it can be ensured that the environmental interference point is the point where the fault still exists under the influence of the environment, thereby improving the accuracy of fault screening, and preventing the misjudgment caused by the greater influence of weather in the fault area during the grounding line selection process, thereby improving the accuracy and success rate of line selection;

[0053] Step S108, obtaining all environmental interference points and environmental impact voltages in the fault line.

[0054] Step S2, analyzing the line in the line fault direction based on the environmental impact voltage and obtaining the selected fault line, detecting the voltage of the grounding point of the selected fault line, and recording the detection result as the fault voltage; Step S2 includes the following sub-steps:

[0055] Step S201: for any environmental interference point, all lines from the environmental interference point to the grounding point of the fault line are recorded as branch lines of the environmental interference point, the current in each branch line is obtained respectively, and the branch line with a current less than the rated current is recorded as a line selection fault line; in the specific implementation process, in this embodiment, the circuit amount in each line is assumed to be the rated current of the line. When the current in the actual line is not the rated current, the object to be compared with the current to screen out the line selection fault circuit can be adjusted;

[0056] Step S202, obtaining the selected fault lines corresponding to all environmental interference points, and recording the voltage in the selected fault line as the fault voltage.

[0057] Step S3, analyzing the fault voltage, and obtaining the fault circuit and the non-fault circuit in the selected fault line based on the analysis result, screening the non-fault circuit, and obtaining the most selected line circuit in the non-fault line based on the screening result;

[0058] Step S301: for any selected faulty line, all circuits in the selected faulty line are recorded as circuits to be analyzed DL1 to DL q , use the current proportion algorithm to obtain the current proportion corresponding to each circuit DL to be analyzed, and the current proportion algorithm includes: Where G is the current ratio, I e is the rated current of the circuit DL to be analyzed, I s is the actual current of the circuit DL to be analyzed, I sum is the rated current of the selected fault line where the circuit to be analyzed is located; in the specific implementation process, for example, in one analysis, the rated current of the circuit to be analyzed DL is 5A, and the actual current of the circuit to be analyzed is 4A, I sum is 10A, then the current ratio can be calculated to be 0.625; by calculating the current ratio, the proportional relationship between the rated current and the actual current of each circuit DL to be analyzed can be obtained, and when the current ratio is large, it means that the actual current of the circuit DL to be analyzed is small, and there may be a circuit fault;

[0059] Step S302, the circuit DL to be analyzed with the largest current ratio among all the circuits DL to be analyzed is recorded as a fault circuit, and the circuits to be analyzed other than the fault circuit are recorded as non-fault circuits;

[0060] For any non-fault circuit, a plane rectangular coordinate system is established, which is recorded as the position screening coordinate system, wherein the units of the X-axis and the Y-axis of the position screening coordinate system are both in meters; based on the positional relationship between the non-fault circuit and the faulty circuit in the map, the non-fault circuit and the faulty circuit are drawn in the position screening coordinate system, and the maximum and minimum values ​​of the distance between the non-fault circuit and the faulty circuit are obtained, which are recorded as the maximum line selection distance and the minimum line selection distance respectively; the value of the maximum line selection distance minus the minimum line selection distance is recorded as the distance difference; the distance differences corresponding to all non-fault circuits are obtained, and the non-fault circuit corresponding to the smallest distance difference is recorded as the most preferred line circuit; in the specific implementation process, by recording the non-fault circuit corresponding to the smallest distance difference as the most preferred line circuit, it is possible to ensure that the efficiency of line replacement is improved when replacing the line, thereby reducing the loss caused by line failure;

[0061] Step S303, record the maximum current that can be passed through the most preferred line circuit as the selected line maximum current; cut off the current supply to the selected line fault line, and increase the circuit supply of the most preferred line circuit until the current in the most preferred line circuit is the selected line maximum current.

[0062] Example 2, please refer to Figure 4 As shown, Figure 4The structural schematic diagram of an electronic device is illustrated, and the electronic device may include: a processor, a communication interface, a memory and a communication bus, wherein the processor, the communication interface and the memory communicate with each other through the communication bus. The memory stores computer-readable instructions, and the processor may call the instructions in the memory. When the computer-readable instructions are executed by the processor, the steps in a method for selecting a small current grounding line for power supply of a hydropower station are executed to realize the following functions: firstly, a signal sensor is set in the grounding line of the line, and when a grounding fault occurs in the line, the line fault direction is obtained based on the detection result of the signal sensor; the environment in the line fault direction is obtained based on a map, and the environment is analyzed to obtain the environmental interference point; the environmental impact voltage in the line fault direction is obtained based on the environmental interference point, and then the line in the line fault direction is analyzed based on the environmental impact voltage and the line selection fault line is obtained, and the voltage of the grounding point of the line selection fault line is detected; finally, the fault voltage is analyzed, and the fault circuit and non-fault circuit in the line selection fault line are obtained based on the analysis result, and the optimal line circuit in the non-fault line is obtained.

[0063] In addition, the logic instructions in the above-mentioned memory can be implemented in the form of software functional units and can be stored in a computer-readable storage medium when sold or used as an independent product. Based on this understanding, the technical solution of the present application can be essentially or partly embodied in the form of a software product that contributes to the prior art, and the computer software product is stored in a storage medium, including several instructions to enable a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present application. The aforementioned storage medium includes: various media that can store program codes, such as a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a disk or an optical disk.

[0064] Embodiment 3, the present application also provides a computer-readable storage medium, the present application provides a storage medium, on which a computer program is stored, and when the computer program is executed by a processor, the steps in the above-mentioned small-current grounding line selection method for hydropower plant power are executed to achieve the following functions: first, a signal sensor is set in the grounding line of the line, and when a grounding fault occurs in the line, the line fault direction is obtained based on the detection result of the signal sensor; the environment in the line fault direction is obtained based on a map, and the environment is analyzed to obtain the environmental interference point; based on the environmental interference point, the environmental impact voltage in the line fault direction is obtained, and then based on the environmental impact voltage, the line in the line fault direction is analyzed and the line selection fault line is obtained, and the voltage of the grounding point of the line selection fault line is detected; finally, the fault voltage is analyzed, and based on the analysis result, the fault circuit and the non-fault circuit in the line selection fault line are obtained and the optimal line circuit in the non-fault line is obtained.

[0065] Through the description of the above implementation methods, the embodiments of the present invention can be provided as methods, systems or computer program products. Based on such an understanding, the above technical solutions can be essentially or partly contributed to the prior art in the form of software products, which can be stored in a computer-readable storage medium, such as ROM / RAM, a magnetic disk, an optical disk, etc., and include several instructions for enabling a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods described in each embodiment or some parts of the embodiments.

[0066] In the embodiments provided in the present application, it should be understood that the disclosed system or method can be implemented in other ways. The embodiments described above are merely schematic. For example, the division of modules or units is only a logical function division. There may be other division methods in actual implementation. For example, multiple modules or units can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some communication interfaces, and the indirect coupling or communication connection of systems, modules and units can be electrical, mechanical or other forms.

[0067] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit it. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A method for selecting a low-current grounding line for power supply in a hydropower station, characterized in that: The steps include: A signal sensor is set in the grounding line of the line. When a grounding fault occurs in the line, the line fault direction is obtained based on the detection result of the signal sensor; the environment in the line fault direction is obtained based on the map, and the environment is analyzed to obtain the environmental interference point; Obtain the environmental impact voltage in the line fault direction based on the environmental interference point; For any environmental interference point, all lines from the environmental interference point to the grounding point of the fault line are recorded as branch lines of the environmental interference point, the current in each branch line is obtained respectively, and the branch line with a current less than the rated current is recorded as the selected fault line; Obtain the selected fault lines corresponding to all environmental interference points, and record the voltage in the selected fault line as the fault voltage; For any selected fault line, all circuits in the selected fault line are recorded as circuits to be analyzed DL1 to circuits to be analyzed DL q , use the current proportion algorithm to obtain the current proportion corresponding to each circuit DL to be analyzed, and the current proportion algorithm includes: , where G is the current ratio, I e is the rated current of the circuit DL to be analyzed, I s is the actual current of the circuit DL to be analyzed, I sum is the rated current of the selected fault line where the circuit to be analyzed is located; The circuit DL to be analyzed with the largest current ratio among all the circuits to be analyzed DL is recorded as a fault circuit, and the circuits to be analyzed other than the fault circuit are recorded as non-fault circuits; For any non-fault circuit, a plane rectangular coordinate system is established, which is recorded as the position screening coordinate system, wherein the units of the X-axis and the Y-axis of the position screening coordinate system are both in meters; based on the positional relationship between the non-fault circuit and the faulty circuit in the map, the non-fault circuit and the faulty circuit are drawn in the position screening coordinate system, and the maximum and minimum values ​​of the distance between the non-fault circuit and the faulty circuit are obtained, which are recorded as the maximum line selection distance and the minimum line selection distance, respectively; the value of the maximum line selection distance minus the minimum line selection distance is recorded as the distance difference; the distance differences corresponding to all non-fault circuits are obtained, and the non-fault circuit corresponding to the minimum distance difference is recorded as the optimal line selection circuit.

2. A method for selecting a small current grounding line for power supply of a hydropower station according to claim 1, characterized in that: When a ground fault occurs in the line, the line fault direction is obtained based on the detection result of the signal sensor, including: Step S101: Record multiple grounding lines as current grounding lines JD1 to JD n ; placing a signal sensor in each current grounding line JD, wherein the signal sensor is used to monitor the current in the current grounding line JD; Establish a plane rectangular coordinate system, recorded as the stable monitoring coordinate system, where the unit of the X-axis of the stable monitoring coordinate system is time, and the unit of the Y-axis is current; for any current grounding line JD n1 , based on the current grounding line JD n1 The signal sensor in the ground line obtains the current JD in the last day n1 The current in the stable monitoring coordinate system is plotted, and the corresponding curve is recorded as the rated current curve EQn1; Get the rated current curve EQ corresponding to all current grounding lines JD.

3. A method for selecting a low-current grounding line for power supply in a hydropower station according to claim 2, characterized in that: When a ground fault occurs in the line, obtaining the line fault direction based on the detection result of the signal sensor also includes: For any current grounding line JD n1 , based on the signal sensor to obtain the current grounding line JD n1 The current in the recent k days without faults is plotted, and the rated current curve EQ corresponding to each day is drawn in the stable monitoring coordinate system, which are recorded as fitting current curves NH1 to NH k ; In the stable monitoring coordinate system, the fitting current curve NH1 is connected to the fitting current curve NH k Fitted into a curve and recorded as the rated reference curve EC n1 ; For the rated reference curve EC n1 Take any point α (x0, y0) in the rated current curve EQn1, and record the point with abscissa x0 in the rated current curve EQn1 as β (x0, y1); record the absolute value of the difference between y1 and y0 as the rated difference; obtain the rated reference curve EC n1 The rated differences of all points in the fault are calculated, and the maximum value of all rated differences is recorded as the fault reference difference.

4. A method for selecting a small current grounding line for power supply of a hydropower station according to claim 3, characterized in that: When a ground fault occurs in the line, the line fault direction is obtained based on the detection result of the signal sensor, the environment is analyzed to obtain the environmental interference point, and the environmental impact voltage of the line fault direction obtained based on the environmental interference point also includes: Get the fault reference difference corresponding to all current grounding lines JD; for any current grounding line JD n1 , based on the signal sensor to obtain the current grounding line JD in real time n1 The current in the stable monitoring coordinate system is marked in real time as the real-time current point; the horizontal coordinate of the real-time current point is marked as x1. When |y2-y3| is greater than the current grounding line JD at any time n1 When the fault reference value is reached, the circuit grounding line JD n1 The direction is recorded as the line fault direction, where y2 is the ordinate of the real-time current point, and y3 is the ordinate of the point with the abscissa x1 in the rated current curve EQn1; When a line fault direction appears, all circuits in the line fault direction are recorded as fault lines; the areas affected by all fault lines are recorded as fault areas in the map; The weather in the fault area is recorded as environmental impact weather. Based on the distribution data of the fault line in the fault area, the potential difference analysis method is used to obtain the environmental interference points and environmental impact voltage in the fault line after the environmental impact weather affects the fault line, wherein the distribution data includes the distribution position of the line in the fault area and the exposure condition of the fault line.

5. A method for selecting a low-current grounding line for power supply in a hydropower station according to claim 4, characterized in that: The potential difference analysis method includes: recording the length of the line as the total length of the line, recording the length of the line exposed to the air as the total exposed length, and recording (total exposed length\total line length)×100% as the exposed ratio; obtaining the total length of the line and the total exposed length of the fault area based on the distribution data of the fault line, recording them as the total length of the fault line and the total length of the fault exposure, respectively, and recording the exposed ratio obtained from the total length of the fault line and the total length of the fault exposure as the fault exposure ratio; simulating the impact of the environment on the weather in a meteorological environment simulation laboratory, and placing a line with a length of the total length of the line in the meteorological environment simulation laboratory, recorded as a simulated circuit; obtaining the voltage between all positions in the simulated circuit and the grounding point of the simulated circuit when the exposure ratio is 0 to 100%, and recording the recorded data as environmental simulation data.

6. A method for selecting a small current grounding line for power supply of a hydropower station according to claim 5, characterized in that: Potentiometric analysis also includes: Obtain data in which the exposed ratio is the fault exposed ratio in the environmental simulation data, and record it as the fault simulation data; obtain the voltage between all positions in the fault line and the grounding point of the fault line, and record it as the actual fault voltage. When the actual fault voltage at any position is not equal to the voltage at the same position in the fault simulation data, record the position as the environmental interference point, and record the voltage between the environmental interference point and the grounding point of the fault circuit as the environmental influence voltage; Obtain all environmental interference points and environmental impact voltages in the fault line.

7. A method for selecting a small current grounding line for power supply of a hydropower station according to claim 6, characterized in that: Also includes: The maximum current that can be passed through the optimal line selection circuit is recorded as the line selection maximum current; The current supply to the faulty circuit is cut off, and the current supply to the most preferred line circuit is increased until the current in the most preferred line circuit reaches the maximum current of the selected line.

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