Distribution line wave velocity measurement and calibration method based on distribution automation master station

Abstract

According to the distribution line wave velocity measurement and calibration method based on the distribution automation master station, the master station sends and uploads an instruction of last wave recording to all traveling wave distance measurement devices of a line where a switch is located after operation of the remote control switch; after receiving the instruction, the traveling wave distance measuring device uploads the last cached recorded wave, namely the recorded wave data started by the switch operation wave, and the main station calculates and updates the wave speed after receiving the recorded wave uploaded by the device. The invention provides the active and easy-to-operate distribution line wave velocity measurement and calibration method, the line wave velocity can be actually measured and calibrated without relying on faults and without a large amount of data statistics, the problem of large distribution line fault positioning error caused by inaccurate wave velocity can be solved, the fault positioning precision is improved, and the fault positioning accuracy is improved. Therefore, the fault processing speed of the distribution line is greatly accelerated, and property loss, personal safety risk and power supply reliability loss caused by the fault are greatly reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of traveling wave ranging, and in particular to a distribution line wave velocity measurement and calibration method based on a distribution automation master station. Background Art

[0002] Traveling wave ranging technology has been maturely applied in transmission networks, but it has not been put into use on a large scale in distribution networks due to technical and cost limitations. With the improvement of the national economic and living standards, the requirements for the operation level of distribution networks are also increasing. The country has also increased its investment in distribution network construction and maintenance. At the same time, breakthroughs in high-frequency sensing technology, high-precision GPS timing technology, high-speed 4G / 5G communication technology and high-frequency synchronous sampling technology have also promoted the realization of distribution network traveling wave ranging technology. In addition, the trend of integration of primary and secondary equipment has also greatly reduced the investment in the installation of traveling wave acquisition devices. Therefore, my country's distribution network has the conditions for applying traveling wave ranging technology. However, unlike transmission lines, distribution lines have a large number of cable lines in addition to overhead lines. Overhead lines are also divided into insulated overhead lines and bare lines. Different line types, line models and complex distribution network line surrounding environments will affect the value of the traveling wave velocity, and thus affect the accuracy of traveling wave ranging.

[0003] The principle of dual-terminal ranging is shown in formula (1):

[0004]

[0005] Where T1 and T2 are the times when the initial fault wave reaches measurement points 1 and 2, respectively, v is the wave velocity, L is the line length between measurement points 1 and 2, and D1 is the distance from the fault point to measurement point 1. As can be seen from formula (1), the accuracy of the wave velocity v directly affects the distance measurement accuracy. At the same time, due to the historical problems of the distribution line ledger, the line length is inaccurate, and it is even more necessary to measure an equivalent wave velocity.

[0006] Therefore, how to obtain accurate traveling wave velocity is an important part of the traveling wave ranging technology of distribution network. Currently, there are four main methods for obtaining wave velocity:

[0007] 1) Calculate theoretical wave velocity using line design parameters. Although this method is the simplest to implement, the phase-to-phase capacitance per unit length and the ground capacitance per unit length required for wave velocity calculation are affected by many factors such as line height, line corridor, and insulating medium, making it difficult to estimate accurately. At the same time, this method does not take into account the error in line length, which will lead to large errors in the final calculated distance measurement results. In severe cases, the calculated fault point will not be in the actual fault section.

[0008] 2) Use the distance measurement results of the out-of-area fault to calibrate the wave speed. If the fault occurs outside the area, the result calculated by formula (1) should be the total length of the line L, so it can be used to calibrate the wave speed. This method has three disadvantages: first, the wave speed still needs to be given according to the design parameters before calibration; second, the calibration depends on the fault event, which must be an out-of-area fault event, and the conditions are harsh; third, the first fault interval can only be measured according to the design wave speed, the error is large, and the wave speed cannot be calibrated automatically. The wave speed can only be calibrated after confirming the actual location of the fault point through inspection.

[0009] 3) Use a large amount of historical statistical data to establish a standard wave velocity library that corresponds to the line model. This method regards the wave velocity as the only parameter corresponding to the line model, and does not consider the concept of equivalent wave velocity when the line length is inaccurate. In addition, it takes a long time to establish the standard wave velocity library, and its practical value is not high.

[0010] 4) The traveling wave ranging device uploads all recorded waves, and the master station identifies the traveling waves generated by the switch operation and uses the ranging results of the operation waves to calibrate the wave speed. The principle of this method is similar to the second method, except that the switch operation waves are used for calibration instead of the out-of-zone fault traveling waves. Although the shortcomings of method 2 are overcome, it will also cause great communication pressure on the master station, and the master station needs to implement an identification algorithm for the operation waves and the real fault traveling waves.

[0011] The present invention provides an active wave velocity measurement calibration method utilizing switch remote control operation, which does not require passive reliance on fault occurrence, does not require long-term data statistics, and has less pressure on master station communication. Summary of the invention

[0012] The present invention proposes a distribution line wave velocity measurement and calibration method, device and storage medium based on a distribution automation master station, which can solve at least one of the technical problems in the background technology.

[0013] To achieve the above object, the present invention adopts the following technical solutions:

[0014] A distribution line wave velocity measurement and calibration method based on a distribution automation master station comprises the following steps:

[0015] Step 1: When the remote control switch is operated, the master station determines whether it is necessary to measure or calibrate the line wave velocity, and if necessary, proceeds to the next step;

[0016] Step 2: The master station sends a switch operation remote control signal;

[0017] Step 3: Confirm that the switch operation is successful. After receiving the remote signal of the switch position change, the master station sends a call for the latest wave recording instruction to all the traveling wave ranging devices on the line where the switch is located;

[0018] Step 4: After receiving the instruction, the traveling wave ranging device generates a recording file with the data of the most recent startup cache, and reports the recording completion SOE to the main station;

[0019] Step 5: The master station receives the recording of the traveling wave ranging device and calls the recording file after completing the SOE;

[0020] Step 6: After receiving the wave recording file uploaded by the traveling wave ranging device, the master station calculates the line mode wave velocity v1 and the zero mode wave velocity v0 of each traveling wave ranging interval according to the uploaded wave recording;

[0021] v1 and v0 represent the wave velocities of the line mode component and the zero mode component in the traveling wave respectively; the line mode and zero mode components are obtained by Karenbauer transformation, as shown in formula (2):

[0022]

[0023] where i α 、i β is the line mode component, i0 is the zero mode component, i A 、i B 、i C is the three-phase current traveling wave, which is obtained from the recording file; the line mode component obtained by formula (2) is used to obtain the initial traveling wave arrival time T1 through the waveform distortion point detection algorithm, and then the recording file of the opposite device is also processed accordingly to obtain the initial traveling wave arrival time T2, and then the line mode wave speed is calculated according to formula (1) under the condition that the distance measurement result, that is, the switch position, is known;

[0024]

[0025] Where T1 and T2 are the times when the initial fault traveling wave reaches measurement points 1 and 2, respectively, v is the wave velocity, L is the line length between measurement points 1 and 2, and D1 is the distance from the fault point to measurement point 1;

[0026] Step 7: Compare with the existing wave speed. If the relative error is greater than the set threshold, update the wave speed.

[0027] Furthermore, the corresponding relationship between the switch position and the distance measurement result is divided into three cases:

[0028] 4) The switch is outside the section. In this case, the distance measurement result corresponding to the switch operation is the total length of the line between devices A and B.

[0029] 5) The switch is on the main line within the section. At this time, the distance measurement result corresponding to the switch operation is the actual position of switch 2, that is, the line distance from switch 2 to devices A and B;

[0030] 6) The switch is on the branch line within the section. At this time, the distance measurement result corresponding to the switch operation is the actual position of the T contact of the branch line, that is, the line distance from the T contact to devices A and B.

[0031] Furthermore, the waveform distortion point detection algorithm includes wavelet transform and Hilbert-Huang transform.

[0032] Furthermore, in step 4, the traveling wave ranging device implements a fault traveling wave screening algorithm, and only uploads the recording completion SOE to the master station when the recording is confirmed to be a fault traveling wave, so that the master station can call for the recording;

[0033] When the traveling wave ranging device is started due to non-fault reasons, it only caches the data. If it receives the "upload the most recent recording" command from the main station, it will form a recording file with the most recently cached recording data and upload the recording completion SOE to the main station.

[0034] Furthermore, the relative error threshold in step seven is set to 1%;

[0035] The relative error is calculated as: (newly measured wave speed - existing wave speed) / existing wave speed.

[0036] On the other hand, the present invention further discloses a computer-readable storage medium storing a computer program, wherein when the computer program is executed by a processor, the processor executes the steps of the above method.

[0037] On the other hand, the present invention further discloses a computer device, including a memory and a processor, wherein the memory stores a computer program, and when the computer program is executed by the processor, the processor executes the steps of the above method.

[0038] It can be seen from the above technical scheme that the distribution line wave velocity measurement and calibration method based on the distribution automation master station of the present invention belongs to the field of traveling wave ranging technology. The present invention utilizes the property that the traveling wave ranging device will be activated due to the operation wave generated by the switch operation. After the distribution automation master station performs the remote control switch operation, it sends an "upload the most recent wave recording" instruction to the traveling wave ranging device on the line where the switch is located. After receiving the instruction, the traveling wave ranging device uploads the cached most recent wave recording to the master station. The master station uses the collected wave recording to call the traveling wave ranging algorithm to calculate the initial traveling wave time difference of each section. If the switch is located outside the section, the ranging result should be the full length of the section. If the switch is located inside the section, the distance to the actual switch location should be based on the ranging result. According to the double-end traveling wave ranging formula (1), the line wave velocity is reversed to perform wave velocity measurement or calibration, as shown in the following formula.

[0039]

[0040] Specifically, the present invention provides a distribution line wave velocity measurement and calibration method based on a distribution automation master station. After the remote control switch is operated, the master station sends an instruction to upload the most recent wave recording to all traveling wave ranging devices on the line where the switch is located. After receiving the instruction, the traveling wave ranging device uploads the most recently cached wave recording data (i.e., the wave recording initiated by the switch operation wave). After receiving the wave recording uploaded by the device, the master station calculates the wave velocity and updates it.

[0041] In summary, the present invention provides an active and easy-to-operate distribution line wave velocity measurement and calibration method, which can measure and calibrate the line wave velocity without relying on faults or requiring a large amount of data statistics. It can solve the problem of large errors in fault location of distribution lines caused by inaccurate wave velocity, improve the fault location accuracy, and thus greatly speed up the distribution line fault processing speed, greatly reducing property losses, personal safety risks and power supply reliability losses caused by faults. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 It is a schematic diagram of the overall process of the present invention;

[0043] Figure 2 It is a schematic diagram of the switch position and the topology of the traveling wave ranging device;

[0044] Figure 3 The figure is a schematic diagram of the line topology and installation position of the traveling wave ranging device according to an embodiment of the present invention. DETAILED DESCRIPTION

[0045] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings 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.

[0046] like Figure 1 As shown, the distribution line wave velocity measurement and calibration method based on the distribution automation master station described in this embodiment includes the following steps:

[0047] Step 1: When the distribution automation master station operates the remote control switch, it determines whether it is necessary to measure or calibrate the line wave velocity, and if necessary, proceeds to the next step;

[0048] Step 2: After the master station confirms all the traveling wave ranging devices within the switch operation influence range according to the line topology, it sends a switch operation remote control signal to the switch;

[0049] Step 3: After the master station confirms that the switch operation is successful and receives the remote signal of the switch position change, it sends a call for the latest wave recording instruction to all the traveling wave ranging devices within the affected range. At this time, the traveling wave ranging devices have been started due to the switch operation wave and cached the wave recording data;

[0050] Step 4: After receiving the "upload the most recent wave recording" instruction, the traveling wave ranging device generates a wave recording file with the most recently cached data, and reports the recording completion SOE to the main station via wireless communication;

[0051] Step 5: After receiving the SOE of the wave recording of the traveling wave ranging device, the master station sends a "wave recording call" command to the device to call the wave recording file. After receiving the "wave recording call" command, the traveling wave ranging device uploads the newly generated wave recording to the master station via wireless communication;

[0052] Step 6: After the master station receives the recording file uploaded by the traveling wave ranging device, it calls the traveling wave ranging algorithm according to the uploaded recording to calculate the line mode wave velocity v1 and zero mode wave velocity v1 of each traveling wave ranging interval. 0。

[0053] v1 and v0 represent the wave velocities of the line mode component and zero mode component in the traveling wave, respectively. The line mode and zero mode components are obtained through Karenbauer transformation, as shown in formula (2):

[0054]

[0055] where i α 、i β is the line mode component, i0 is the zero mode component, i A 、i B 、i C is the three-phase current traveling wave, obtained from the recording file. The line mode component obtained by formula (2) is obtained through the waveform distortion point detection algorithm (such as wavelet transform, Hilbert-Huang transform, etc.) to obtain the initial traveling wave arrival time T1, and then the recording file of the opposite device is also processed accordingly to obtain the initial traveling wave arrival time T2, and then the line mode wave velocity is calculated according to formula (1) under the condition of known ranging results (i.e. switch position). The processing of zero mode wave velocity is similar to this and will not be repeated.

[0056] The corresponding relationship between the operating switch position and the distance measurement result can be divided into three cases: Figure 2 For example, device A and device B are traveling wave ranging devices, switch 1 is an out-of-area switch, switch 2 is an in-area switch, and switch 3 is an in-area branch line switch. Different switch operations correspond to different ranging results, as described below:

[0057] 7) The switch is outside the section, such as Figure 2 The position of switch 1 is shown in the figure. The distance measurement result corresponding to the switch operation at this time is the total length of the line between devices A and B;

[0058] 8) The switch is on the main line within the section, such as Figure 1 The distance measurement result corresponding to the switch operation is the actual position of switch 2, that is, the line distance from switch 2 to devices A and B;

[0059] 9) The switch is on the branch line within the section, such as Figure 1 The distance measurement result corresponding to the switch operation is the actual position of the branch line T contact, that is, the line distance from the T contact to devices A and B, as shown in Figure 2 shown.

[0060] Step 7: Compare with the existing wave speed. If the relative error is greater than the set threshold, update the wave speed.

[0061] Preferably, in step 4, the traveling wave ranging device implements a fault traveling wave screening algorithm, and only uploads the recording completion SOE to the master station when the recording is confirmed to be a fault traveling wave, so that the master station can call for recording. When the traveling wave ranging device is started due to non-fault reasons, it only caches the data. If it receives the "upload the most recent recording" command from the master station, it forms a recording file with the most recently cached recording data, and uploads the recording completion SOE to the master station.

[0062] Preferably, the relative error threshold is set to 1% in step 7. The relative error is calculated as: (newly measured wave speed - existing wave speed) / existing wave speed.

[0063] The following are examples:

[0064] Figure 3 This is a schematic diagram of an actual distribution network cable power supply line, in which traveling wave ranging devices are installed at switches K101, K107, K204 and K201. Now the branch line ring main unit outgoing line needs to be powered on and closed. The closing switch position is as follows Figure 3 As shown, the line wave velocity measurement and calibration are performed using this switch closing operation.

[0065] Step 1: When the master station has a remote control closing requirement, it is determined that the wave speed of the line where the switch is located needs to be calibrated;

[0066] Step 2: Master station remotely closes the circuit breaker;

[0067] Step 3: After receiving the switch position change remote signal confirming the successful closing, the master station sends the "upload the latest wave recording" command to all the traveling wave ranging devices on the line;

[0068] Step 4: After receiving the instruction, the traveling wave ranging device generates a recording file with the cached latest recording data and sends the recording to the master station to complete the SOE;

[0069] Step 5: After receiving the recording completion SOE sent by the traveling wave ranging device, the master station sends a "recording call" command to the traveling wave ranging device;

[0070] Step 6: After the traveling wave ranging devices at K101, K107, K204 and K201 receive the "recording call" command from the main station, they upload the newly generated recording file to the main station via wireless communication;

[0071] Step 7. The master station calculates the line mode and zero mode components at each device based on the received recording file, and calibrates the line mode and zero mode wave velocities based on the ranging results corresponding to the switch positions. The ranging results corresponding to the K101 and K107 traveling wave ranging devices are the branch line T contact positions, which are 1660m away from the K101 switch and 5730m away from the K107 switch. The ranging results of K107 and K204 are 8890m in total length of their section lines. The total length of their section lines for K204 and K201 is 12800m. By calling the traveling wave ranging algorithm to obtain the time when the wave head arrives at each device, the line mode and zero mode wave velocities can be calculated using formula (3).

[0072] In summary, the present invention provides an active and easy-to-operate distribution line wave velocity measurement and calibration method, which can measure and calibrate the line wave velocity without relying on faults or requiring a large amount of data statistics. It can solve the problem of large errors in fault location of distribution lines caused by inaccurate wave velocity, improve the fault location accuracy, and thus greatly speed up the distribution line fault processing speed, greatly reducing property losses, personal safety risks and power supply reliability losses caused by faults.

[0073] On the other hand, the present invention further discloses a computer-readable storage medium storing a computer program, wherein when the computer program is executed by a processor, the processor executes the steps of the above method.

[0074] On the other hand, the present invention further discloses a computer device, including a memory and a processor, wherein the memory stores a computer program, and when the computer program is executed by the processor, the processor executes the steps of the above method.

[0075] In another embodiment provided in the present application, a computer program product comprising instructions is also provided, which, when executed on a computer, enables the computer to execute any of the distribution line wave velocity measurement and calibration methods based on a distribution automation master station in the above embodiments.

[0076] It is understandable that the system, device and storage medium provided in the embodiments of the present invention correspond to the method provided in the embodiments of the present invention, and the explanation, examples and beneficial effects of the relevant contents can refer to the corresponding parts in the above methods.

[0077] In the above embodiments, it can be implemented in whole or in part by software, hardware, firmware or any combination thereof. When implemented using software, it can be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, the process or function described in the embodiment of the present application is generated in whole or in part. The computer may be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions may be stored in a computer-readable storage medium, or transmitted from one computer-readable storage medium to another computer-readable storage medium, for example, the computer instructions may be transmitted from a website site, computer, server or data center by wired (e.g., coaxial cable, optical fiber, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) mode to another website site, computer, server or data center. The computer-readable storage medium may be any available medium that a computer can access or a data storage device such as a server or data center that includes one or more available media integration. The available medium may be a magnetic medium, (e.g., a floppy disk, a hard disk, a tape), an optical medium (e.g., a DVD), or a semiconductor medium (e.g., a solid-state drive Solid State Disk (SSD)), etc.

[0078] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.

[0079] Each embodiment in this specification is described in a related manner, and the same or similar parts between the embodiments can be referred to each other, and each embodiment focuses on the differences from other embodiments. In particular, for the system embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and the relevant parts can be referred to the partial description of the method embodiment.

[0080] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. 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 invention.

Claims

1. A distribution line wave velocity measurement and calibration method based on a distribution automation master station, characterized in that: The following steps are included: Step 1: When the remote control switch is operated, the master station determines whether it is necessary to measure or calibrate the line wave velocity, and if necessary, proceeds to the next step; Step 2: The master station sends a switch operation remote control signal; Step 3: Confirm that the switch operation is successful. After receiving the remote signal of the switch position change, the master station sends a call for the latest wave recording instruction to all the traveling wave ranging devices on the line where the switch is located; Step 4: After receiving the instruction, the traveling wave ranging device generates a recording file with the data of the most recent startup cache, and reports the recording completion SOE to the main station; Step 5: The master station receives the recording of the traveling wave ranging device and calls the recording file after completing the SOE; Step 6: After receiving the wave recording file uploaded by the traveling wave ranging device, the master station calculates the line mode wave velocity v1 and the zero mode wave velocity v0 of each traveling wave ranging interval according to the uploaded wave recording; v1 and v0 represent the wave velocities of the line mode component and the zero mode component in the traveling wave respectively; the line mode and zero mode components are obtained by Karenbauer transformation, as shown in formula (2): where i α 、i β is the line mode component, i0 is the zero mode component, i A 、i B 、i C is the three-phase current traveling wave, which is obtained from the recording file; the line mode component obtained by formula (2) is used to obtain the initial traveling wave arrival time T1 through the waveform distortion point detection algorithm, and then the recording file of the opposite device is also processed accordingly to obtain the initial traveling wave arrival time T2, and then the line mode wave speed is calculated according to formula (1) under the condition that the distance measurement result, that is, the switch position, is known; Where T1 and T2 are the times when the initial fault traveling wave reaches measurement points 1 and 2, respectively, v is the wave velocity, L is the line length between measurement points 1 and 2, and D1 is the distance from the fault point to measurement point 1; Step 7: Compare with the existing wave speed. If the relative error is greater than the set threshold, update the wave speed.

2. The distribution line wave velocity measurement and calibration method based on the distribution automation master station according to claim 1 is characterized in that: The corresponding relationship between the switch position and the distance measurement result can be divided into three cases: Device A and device B are traveling wave ranging devices, switch 1 is an out-of-area switch, switch 2 is an in-area switch, and switch 3 is a switch on the branch line in the area. Different switch operations correspond to different ranging results; 1) The switch is outside the section. In this case, the distance measurement result corresponding to the switch operation is the total length of the line between device A and device B; 2) The switch is on the main line in the section. At this time, the distance measurement result corresponding to the switch operation is the actual position of switch 2, that is, the line distance from switch 2 to device A and device B; 3) The switch is on the branch line within the section. At this time, the distance measurement result corresponding to the switch operation is the actual position of the T contact of the branch line, that is, the line distance from the T contact to device A and device B.

3. The distribution line wave velocity measurement and calibration method based on the distribution automation master station according to claim 2 is characterized in that: The waveform distortion point detection algorithms include wavelet transform and Hilbert-Huang transform.

4. The distribution line wave velocity measurement and calibration method based on the distribution automation master station according to claim 1 is characterized in that: In step 4, the traveling wave ranging device implements the fault traveling wave screening algorithm, and only uploads the recording SOE to the main station when the recording is confirmed to be a fault traveling wave, so that the main station can call for the recording; When the traveling wave ranging device is started due to non-fault reasons, it only caches the data. If it receives the "upload the most recent recording" command from the main station, it will form a recording file with the most recently cached recording data and upload the recording completion SOE to the main station.

5. The distribution line wave velocity measurement and calibration method based on the distribution automation master station according to claim 1 is characterized in that: In step 7, the relative error threshold is set to 1%; The relative error is calculated as: (newly measured wave speed - existing wave speed) / existing wave speed.

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