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

Abstract

The present invention provides a distribution line wave velocity measurement and calibration method based on a distribution automation master station. Following a remote control switch operation, the master station sends a command to all traveling wave ranging devices on the switch's line to upload their most recent wave recording. Upon receiving the command, the traveling wave ranging devices upload their most recently cached wave recording, i.e., the wave recording data initiated by the switch operation. After receiving the uploaded wave recording, the master station calculates and updates the wave velocity. This invention provides an active and easy-to-use distribution line wave velocity measurement and calibration method. This method measures and calibrates line wave velocity without relying on faults or requiring extensive data statistics. This method addresses the large errors in distribution line fault location caused by inaccurate wave velocity, improves fault location accuracy, and significantly accelerates distribution line fault handling, significantly reducing property losses, personal safety risks, and power supply reliability losses caused by faults.

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 yet to be widely implemented in distribution networks due to technical and cost limitations. With the improvement of national economic and living standards, the requirements for the operational performance of distribution networks are also increasing. The country has also increased investment in distribution network construction and maintenance. 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 facilitated the implementation of traveling wave ranging technology in distribution networks. Furthermore, the trend of integrating primary and secondary equipment has significantly reduced the installation cost of traveling wave acquisition devices. Therefore, my country's distribution network is ready for the application of traveling wave ranging technology. However, unlike transmission lines, distribution lines include a large number of cable lines in addition to overhead lines. Overhead lines are also divided into insulated overhead lines and bare wires. Different line types and models, as well as the complex surrounding environment of distribution lines, can affect the traveling wave velocity value and, in turn, 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 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. 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 historical issues in 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 to obtain the wave velocity:

[0007] 1) Calculate theoretical wave velocity using line design parameters. While 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 multiple factors, such as line height, line corridor, and insulation medium, making accurate estimation difficult. Furthermore, this method does not account for errors in line length, resulting in significant errors in the final distance measurement. In severe cases, the calculated fault point may not be in the actual fault zone.

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

[0009] 3) Utilize a large amount of historical statistical data to establish a standard wave velocity library that corresponds to each line model. This method considers 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. Furthermore, establishing a standard wave velocity library takes a long time and has low practical value.

[0010] 4) The traveling wave ranging device uploads all recorded waves. The master station identifies the traveling waves generated by the switch operation and uses the ranging results of the operating waves to calibrate the wave velocity. This method is similar in principle to the second method, differing in that it uses the switch operating waves for calibration rather than the traveling waves of the out-of-zone fault. While this overcomes the shortcomings of method 2, it also places significant communication pressure on the master station and requires the master station to implement an algorithm to distinguish between operating waves and true fault traveling waves.

[0011] The present invention provides an active wave velocity measurement calibration method using 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 includes the following steps:

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

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

[0017] Step 3: After confirming that the switch operation is successful and receiving the remote signal of the switch position change, the master station sends a call for the latest recording instruction to all 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 master station;

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

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

[0021] 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 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 velocity is calculated according to formula (1) under the condition that the ranging 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 velocity. If the relative error is greater than the set threshold, update the wave velocity.

[0027] Furthermore, the correspondence 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 full length of the line between devices A and B.

[0029] 5) The switch is on the main line within the section. In this case, 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 a branch line within the section. 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 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] In another aspect, 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, comprising 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 solution 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 by the operating 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 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 recording to the master station. The master station uses the collected recording to call the traveling wave ranging algorithm to calculate the initial traveling wave time difference of each section. If the switch is outside the section, the ranging result should be the full length of the section. If the switch is inside the section, the distance to the actual switch location should be based on the ranging result. The line wave velocity is inferred according to the double-end traveling wave ranging formula (1) 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 distribution line fault location errors caused by inaccurate wave velocity, improve fault location accuracy, and thus greatly speed up the distribution line fault processing speed, significantly 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 Schematic diagram of switch position and traveling wave ranging device topology;

[0044] Figure 3 This 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 operating the remote control switch, the distribution automation master station determines whether it is necessary to measure or calibrate the line wave velocity, and if so, proceeds to the next step;

[0048] Step 2: After the master station confirms all traveling wave ranging devices within the range affected by the switch operation based on 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 recording instruction to all 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 recording data;

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

[0051] Step 5: After the master station receives the SOE of the recording of the traveling wave ranging device, it sends a "recording call" command to the device to call the recording file. After receiving the "recording call" command, the traveling wave ranging device uploads the newly generated recording file 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 based on 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 from Equation (2) is applied to a waveform distortion point detection algorithm (such as wavelet transform or Hilbert-Huang transform) to obtain the initial traveling wave arrival time T1. The recording file of the peer device is then processed accordingly to obtain the initial traveling wave arrival time T2. The line mode wave velocity is then calculated according to Equation (1) given the known ranging result (i.e., the switch position). The processing for the zero mode wave velocity is similar and will not be repeated here.

[0056] The corresponding relationship between the operating switch position and the distance measurement result is 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 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 1. Figure 2 shown.

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

[0061] Preferably, in step 4, the traveling wave ranging device implements a fault traveling wave screening algorithm and uploads the recording completion SOE to the master station only when the recording is confirmed to be a faulty 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 data. Upon receiving 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 examples illustrate:

[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 outgoing line of the ring main unit needs to be energized and closed. The closing switch position is as follows Figure 3 As shown, this switch closing operation is used to measure and calibrate the line wave velocity.

[0065] Step 1: When the master station has a remote closing requirement, it is determined that the wave velocity 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 telesignal confirming the successful closing, the master station sends the "upload the latest wave recording" command to all 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 file 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 receiving the "wave recording call" command from the master station, the traveling wave ranging devices at K101, K107, K204 and K201 upload the newly generated wave recording file to the master 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 for the 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 distribution line fault location errors caused by inaccurate wave velocity, improve fault location accuracy, and thus greatly speed up the distribution line fault processing speed, significantly reducing property losses, personal safety risks and power supply reliability losses caused by faults.

[0073] In another aspect, 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, comprising 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 containing instructions is also provided. When the computer is run on the computer, the computer executes any of the distribution line wave velocity measurement and calibration methods based on the 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 of 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 software is used for implementation, 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 can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can 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 can be transmitted from a website, computer, server or data center to another website, computer, server or data center via a wired (e.g., coaxial cable, optical fiber, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) method. The computer-readable storage medium can 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 integrations. The available medium can 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 (SSD)).

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

[0079] Each embodiment in this specification is described in a related manner. Similar parts between the various embodiments can be referred to in conjunction with each other. Each embodiment focuses on the differences between the other embodiments. In particular, the system embodiment is generally similar to the method embodiment, so the description is relatively simple. For related parts, refer to the 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 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 various 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 operating the remote control switch, the master station determines whether it is necessary to measure or calibrate the line wave velocity, and if so, proceeds to the next step; Step 2: The master station sends a switch operation remote control signal; Step 3: After confirming that the switch operation is successful and receiving the remote signal of the switch position change, the master station sends a call for the latest recording instruction to all 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 master station; Step 5: The master station receives the recording data of the traveling wave ranging device and calls the recording file after completing the SOE. Step 6: After receiving the recording file uploaded by the traveling wave ranging device, the master station calculates the line mode wave velocity v1 and zero mode wave velocity v0 of each traveling wave ranging interval based on the uploaded recording file; v1 and v0 represent the wave velocities of the line mode component and zero mode component in the traveling wave, respectively. The line mode component and the zero mode component are obtained through Karen Bell transformation, as shown in formula (2): (2) in 、 is the line mode component, is the zero mode component, 、 、 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 through the waveform distortion point detection algorithm Then process the recording file of the other end device accordingly to obtain the initial traveling wave arrival time , then, under the condition of knowing the distance measurement result, i.e. the switch position, the line wave velocity is inversely calculated according to formula (1); (1) Where T1 and T2 are the times when the initial fault traveling wave reaches measurement points 1 and 2 respectively, v is the line 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 the newly measured line wave velocity with the existing wave velocity. If the relative error is greater than the set threshold, update the wave velocity.

2. The method for measuring and calibrating the wave velocity of a distribution line based on a distribution automation master station according to claim 1 is characterized in that: The corresponding relationship between the switch position and the distance measurement result is divided into three cases: Devices A and 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 a 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 full length of the line between device A and device B. 2) The switch is on the main line within the section. In this case, 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 a branch line within the section. In this case, 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 method for measuring and calibrating distribution line wave velocity based on a distribution automation master station according to claim 2, characterized in that: Waveform distortion point detection algorithms include wavelet transform and Hilbert-Huang transform.

4. The method for measuring and calibrating the wave velocity of a distribution line based on a 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 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; 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 will form a recording file with the most recently cached recording data and upload the recording completion SOE to the master station.

5. The method for measuring and calibrating distribution line wave velocity based on a distribution automation master station according to claim 1, 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.

Images