Power distribution network fault detection and rapid fixed point system

Abstract

The invention discloses a power distribution network fault detection and rapid fixed point system, and the system comprises a fault recording device which is used for detecting the waveform and data of a power grid before, when and after a fault occurs, and providing a basis for fault analysis; the signal generating device is used for detecting the signal intensity; when the signal intensity between the signal generation device and the supervision operation platform is higher than a set threshold value, the fault recording equipment transmits detection data to the supervision operation platform through the signal generation device, and the supervision operation platform judges the fault type according to the data and estimates the fault occurrence distance by adopting a corresponding algorithm according to the fault type; when the signal intensity between the signal generation device and the supervision operation platform is lower than a set threshold value, the signal generation device transmits data to a data processing module, the fault type is judged through the handheld operation terminal according to the read data, and the fault occurrence distance is estimated by adopting a corresponding algorithm according to the fault type; therefore, the detection and troubleshooting workload of maintenance personnel is reduced.

Description

Technical Field

[0001] The present invention belongs to the technical field of distribution network detection; in particular, it relates to a distribution network fault detection and rapid positioning system. Background Art

[0002] In the power system of the distribution network, once a fault occurs, it is necessary to quickly determine the cause and location of the fault, and promptly repair the power supply to reduce the power outage time downstream of the fault point in the power system and reduce the power outage loss; in the traditional technology, detection devices are arranged in the power grid. After a fault occurs, a signal is sent to the total control cloud for prompt. This method can only roughly judge the faulty line, cannot detect the fault type to reduce the troubleshooting scope, and the determination of the fault location is not accurate enough. Moreover, when the signal is interfered, the data transmission may be interrupted frequently or packet loss may occur. If some data fails to be transmitted successfully during this process, it will lead to an incomplete file, resulting in incomplete transmission of fault information. After the workers arrive at the scene, they can only conduct manual troubleshooting. Summary of the Invention

[0003] The technical problem to be solved by the present invention is: to provide a distribution network fault detection and rapid positioning system to solve the technical problems in the prior art that the distribution network fault detection can only roughly judge the faulty line, cannot detect the fault type to reduce the troubleshooting scope, the determination of the fault location is not accurate enough, and when the signal is interfered, the data transmission may be interrupted frequently or packet loss may occur, resulting in an incomplete file, incomplete transmission of fault information, and the workers can only conduct manual troubleshooting after arriving at the scene.

[0004] The technical solution of the present invention:

[0005] A distribution network fault detection and rapid positioning system, the system includes:

[0006] Fault recording equipment: used to detect the waveforms and data of the power grid before, during, and after the fault occurs, providing a basis for fault analysis;

[0007] Signal generating device: connected to the supervision operation platform, detecting the signal intensity;

[0008] When the signal intensity between the signal generating device and the supervision operation platform is higher than the set threshold, the fault recording equipment transmits the detected data to the supervision operation platform through the signal generating device. The supervision operation platform judges the fault type according to the data and estimates the fault occurrence distance by using the corresponding algorithm according to the fault type;

[0009] When the signal strength between the signal generating device and the supervision computing platform is lower than the set threshold, the signal generating device transmits data to the data processing module, and the data processing module integrates and conveys the data to be stored in the data memory; when the worker arrives at the scene, a wired data connection is established between the handheld computing terminal and the data memory, the data in the data memory is read, the fault type is judged based on the read data through the handheld computing terminal, and the fault occurrence distance is estimated using the corresponding algorithm according to the fault type.

[0010] The data processing module and the supervision computing platform integrate a hierarchical transmission algorithm. When the signal strength between the signal generating device and the supervision computing platform is lower than the set threshold, the data integrated into the data memory is processed and then transmitted to the supervision computing platform through the signal generating device.

[0011] The fault types include single-phase grounding fault, two-phase short-circuit fault, two-phase short-circuit grounding fault, and three-phase short-circuit fault.

[0012] After judging as a single-phase grounding fault, the following formula is used to calculate the fault distance:

[0013]

[0014] After judging as a two-phase short-circuit fault, the following formula is used to calculate the fault distance:

[0015]

[0016] After judging as a two-phase short-circuit grounding fault, the following formula is used to calculate the fault distance:

[0017]

[0018] After judging as a three-phase short-circuit fault, the following formula is used to calculate the fault distance:

[0019]

[0020] Where: d is the fault distance; Z line is the wave impedance of the line; is the system frequency; is the voltage at the fault point; U1 is the positive-sequence voltage; I1 is the positive-sequence current; is the negative-sequence voltage between two phases after the fault; U2 is the steady-state negative-sequence voltage before the fault; Z1, Z2, and Z0 are the positive-sequence, negative-sequence, and zero-sequence impedances of the fault point respectively.

[0021] The hierarchical transmission algorithm includes:

[0022] S1. File splitting and numbering: Let the file be F with a size of S; determine the data block size B; the number of data blocks For the i-th data block Fi in file F i (0 ≤ i < N), its size is B i ; when i < N - 1, B i = B; when i = N - 1, B i = S - (N - 1)B; Assign a unique identifier ID i and priority P i to each data block. The priority can be determined according to the position of the data block in the file and the importance of the content;

[0023] S2. Checksum calculation: Calculate the checksum value of the data block using multiple checksum algorithms. Suppose there are m checksum algorithms used, which are C j (F i ), where j = 1, 2,..., m; Define the comprehensive checksum where w j is the weight of each checksum algorithm, satisfying

[0024] S3. Transmission strategy: Determine the transmission order according to the data block priority and the current network condition. Suppose the network condition evaluation index is Q, which can be determined by measuring network bandwidth, latency, and packet loss rate; Define the transmission priority function where is a function adjusted according to the network condition; Sort the data blocks in descending order of the transmission priority TP i for transmission;

[0025] S4. Feedback mechanism: After the receiving end receives the data block, calculate the comprehensive checksum C' total (F i ); If C' total (F i ) = C total (F i ), then send an acknowledgment message ACK to the sending end and feedback the current network condition parameters; If they are not equal, send a request for retransmission message NACK; The sending end adjusts the transmission strategy according to the network condition feedback by the receiving end;

[0026] S5. File recombination: The receiving end stores the received data blocks in the temporary storage area in order according to the identifier ID i ; After receiving all the data blocks, recombine the data blocks into the original file F in the order of the identifiers; Suppose the recombined file is F', then where ∪ represents the merge operation.

[0027] The handheld computing terminal includes a processor module, a battery module and a display screen. The battery module is used to power the processor module and the display screen. When the handheld computing terminal establishes a wired data connection with the data storage device, the processor module can read the data in the data storage device, determine the fault type and use the corresponding algorithm based on the fault type to estimate the distance to the fault, and then display it on the handheld computing terminal through the display screen.

[0028] Beneficial effects of the present invention:

[0029] The distribution network fault detection and rapid location system of the present invention can determine the fault type based on the waveforms detected by the fault recording equipment before and after the fault occurs, and calculate the distance to the fault point at the same time, thereby reducing the detection and troubleshooting workload of maintenance personnel.

[0030] The present invention cooperates with structures such as a data storage device, a data processing module and a handheld computing terminal. When the signal strength between the signal generating device and the monitoring computing platform is poor, the file data can be stored in the data storage device. After the worker arrives at the site, wired reading is performed through the handheld computing terminal, which can avoid file defects caused by forced transmission under poor signal conditions. At the same time, local calculations are performed through the handheld computing terminal, which can also shorten the troubleshooting time of maintenance personnel.

[0031] The present invention processes data before uploading through the set hierarchical transmission algorithm, which can split large files and determine the transmission order according to network conditions and data block importance through data block priority and dynamic adjustment mechanism. When the signal strength between the signal generating device and the supervision operation platform is poor, the completeness and stability of data transmission can be guaranteed.

[0032] The invention solves the technical problems that the existing distribution network fault detection technology can only roughly determine the fault line, cannot detect the fault type and reduce the investigation scope, and is not accurate enough in determining the fault location. In addition, when the signal is interfered with, data transmission may be frequently interrupted or packet loss may occur, resulting in incomplete files and incomplete transmission of fault information. Workers can only manually investigate after arriving at the site. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 This is a system block diagram of the present invention.

[0034] Figure 2 This is a typical recording diagram of a single-phase grounding fault in the present invention.

[0035] Figure 3 This is a typical waveform recording of a two-phase short-circuit fault in the present invention.

[0036] Figure 4 This is a typical waveform recording of a two-phase short-circuit grounding fault in the present invention.

[0037] Figure 5 This is the typical oscillogram of the three-phase short-circuit fault of the present invention. Specific embodiments

[0038] Please refer to Figures 1 to 5 , the present invention provides a technical solution: a distribution network fault detection and rapid location system, including a fault recording device, a signal generating device, a supervision operation platform, a data memory, a data processing module and a handheld operation terminal. The fault recording device usually continuously monitors the electrical quantities in the power system. When it detects that the electrical quantities change suddenly or exceed the set threshold, the device determines that a fault may have occurred in the system and immediately starts the recording function. It digitally collects various electrical quantities at a high sampling frequency. The fault recording device detects the waveforms and data of the power grid before, during and after the fault occurs, providing a basis for fault analysis. The supervision operation platform includes a signal transceiver module, a processing operation system, a display interaction system, etc. The signal generating device has a signal intensity detection function. The signal generating device is equipped with a built-in signal intensity monitoring module, which can monitor the intensity indicators of the signal in real time, such as amplitude, power, etc.;

[0039] When the signal intensity between the signal generating device and the supervision operation platform is higher than the set threshold, the fault recording device transmits the detection data to the supervision operation platform through the signal generating device. The supervision operation platform judges the fault type according to the data and estimates the fault occurrence distance by using the corresponding algorithm according to the fault type; the setting of the signal intensity threshold is judged according to the stability of data transmission under the current signal intensity, and it is necessary to ensure that after the signal intensity threshold is exceeded, there are no problems of data transmission interruption and packet loss;

[0040] When the signal intensity between the signal generating device and the supervision operation platform is lower than the set threshold, the signal generating device transmits the data to the data processing module, and the data processing module integrates and conveys the data to the data memory for storage; when the worker arrives at the scene, a wired data connection is established between the handheld operation terminal and the data memory to read the data in the data memory. The handheld operation terminal is a small mobile device that the worker can carry with him. A data connection line is set on the handheld operation terminal, and a corresponding data socket is set on the data memory. The data is read by corresponding plugging of the data connection line and the data socket.

[0041] The handheld operation terminal determines the fault type based on the read data, and estimates the fault occurrence distance using the corresponding algorithm according to the fault type; the handheld operation terminal includes a processor module, a battery module, and a display screen. The processor module ensures the core processor and its additional cooperating circuits, and by programming the algorithm, it determines the fault type according to the waveform after reading the data, and calculates the fault distance according to the corresponding fault type through the built-in algorithm. The battery module is used to supply power to the processor module and the display screen. The battery module uses a traditional rechargeable battery. When the handheld operation terminal establishes a wired data connection with the data memory, the processor module can read the data in the data memory, determine the fault type, estimate the fault occurrence distance using the corresponding algorithm, and then display it on the handheld operation terminal through the display screen.

[0042] The hierarchical transmission algorithm is integrated in the data processing module and the supervision operation platform. When the signal strength between the signal generating device and the supervision operation platform is lower than the set threshold, the hierarchical transmission algorithm can process the data integrated into the data memory and then transmit it to the supervision operation platform through the signal generating device. That is, when the signal strength between the signal generating device and the supervision operation platform is lower than the set threshold, first integrate the data into the data memory for storage, then process the data through the hierarchical transmission algorithm, and transmit it to the supervision operation platform through the signal generating device. The hierarchical transmission algorithm can optimize the segmentation of large data files, determine the transmission order according to the network condition and the importance of data blocks, and can ensure the integrity and stability of data transmission when the signal strength between the signal generating device and the supervision operation platform is poor.

[0043] In a large current grounding system, the main power system faults include single-phase grounding fault, two-phase short circuit fault, two-phase short circuit grounding fault, and three-phase short circuit fault. Among them, the single-phase grounding short circuit fault is relatively common, accounting for more than 75% of the distribution line faults, while the three-phase short circuit fault is relatively rare.

[0044] Judge the fault type according to the following fault characteristics:

[0045] The typical oscillogram of a single-phase grounding fault is as Figure 2 shown. Its characteristics are that the voltage of the faulty phase decreases significantly, the current of the faulty phase increases significantly, and at the same time, zero-sequence current and zero-sequence voltage are generated; the current and voltage of the non-faulty phases remain unchanged; the zero-sequence current is in the same direction as the faulty-phase current, leading the zero-sequence voltage system impedance angle by about 100°; the zero-sequence voltage is in the opposite direction to the faulty-phase voltage, and the faulty-phase current lags the faulty-phase voltage system impedance angle by about 80°.

[0046] The typical oscillogram of a two-phase short circuit fault is as Figure 3As shown, it is characterized by a sharp increase in the current of the two short - circuited phases and a sharp decrease in the voltage of the two short - circuited phases; no zero - sequence voltage and zero - sequence current appear; the current directions of the two faulty phases are opposite; the phase - to - phase voltage of the two faulty phases leads the phase - to - phase current of the two faulty phases by about 75° of the system impedance angle.

[0047] The typical oscillogram of a two - phase short - circuit grounding fault is as shown in Figure 4 As shown, it is characterized by a large increase in the current of the two faulty phases and a decrease in the voltage of the two faulty phases; zero - sequence current and zero - sequence voltage are generated; the phase - to - phase voltage of the two faulty phases leads the phase - to - phase current of the two faulty phases by about 75° of the system impedance angle; the generated zero - sequence current leads the zero - sequence voltage by about 100° of the system impedance angle.

[0048] The typical oscillogram of a three - phase short - circuit fault is as shown in Figure 5 As shown, it is characterized by the fact that the three phases are still symmetrical during the fault, the three - phase voltages decrease simultaneously, the three - phase currents increase simultaneously, and the fault characteristics are obvious; there are no zero - sequence voltage and current components; the phase voltage leads the phase current by about 75° of the system impedance angle.

[0049] After judging as a single - phase grounding fault, the following formula is used to calculate the fault distance:

[0050]

[0051] After judging as a two - phase short - circuit fault, the following formula is used to calculate the fault distance:

[0052]

[0053] After judging as a two - phase short - circuit grounding fault, the following formula is used to calculate the fault distance:

[0054]

[0055] After judging as a three - phase short - circuit fault, the following formula is used to calculate the fault distance:

[0056]

[0057] Where: d is the fault distance; Z line is the wave impedance of the line; is the system frequency; is the voltage at the fault point; U1 is the positive - sequence voltage; I1 is the positive - sequence current; is the negative - sequence voltage between two phases after the fault; U2 is the steady - state negative - sequence voltage before the fault; Z1, Z2, and Z0 are the positive - sequence, negative - sequence, and zero - sequence impedances of the fault point respectively.

[0058] The hierarchical transmission algorithm is as follows:

[0059] S1. File splitting and numbering: Let the file be F, and its size be S; determine the data - block size B; the number of data blocks For the i-th data block Fi in file F i (0 ≤ i < N), its size is B i ; when i < N - 1, B i = B; when i = N - 1, B i = S - (N - 1)B; Assign a unique identifier ID i and priority P i to each data block. The priority can be determined according to the position of the data block in the file and the importance of the content;

[0060] S2. Checksum calculation: Calculate the checksum value of the data block using multiple checksum algorithms. Suppose there are m checksum algorithms used, which are C j (F i ), where j = 1, 2,..., m; Define the comprehensive checksum where w j is the weight of each checksum algorithm, satisfying

[0061] S3. Transmission strategy: Determine the transmission order according to the data block priority and the current network condition. Suppose the network condition evaluation index is Q, which can be determined by measuring network bandwidth, latency, and packet loss rate; Define the transmission priority function where is a function adjusted according to the network condition; Sort the data blocks in descending order of transmission priority TP i for transmission;

[0062] S4. Feedback mechanism: After the receiving end receives the data block, calculate the comprehensive checksum C' total (F i ); If C' total (F i ) = C total (F i ), then send an acknowledgment message ACK to the sending end and feedback the current network condition parameters; If they are not equal, send a request for retransmission message NACK; The sending end adjusts the transmission strategy according to the network condition feedback from the receiving end;

[0063] S5. File recombination: The receiving end stores the received data blocks in the temporary storage area in order according to the identifier ID i ; After receiving all the data blocks, recombine the data blocks into the original file F in the order of the identifiers; Suppose the recombined file is F', then where ∪ represents the merge operation.

[0064] The above file reorganization is carried out in the supervision operation platform. After the file reorganization is completed in the supervision operation platform, it can ensure the accuracy of receiving data under the condition of strong signal interference. At this time, the fault type and distance can be displayed and judged in the supervision operation platform.

Claims

1. A distribution network fault detection and rapid positioning system, characterized in that: The system includes: A fault recording device: used to detect the waveforms and data of the power grid before, during, and after a fault occurs, providing a basis for fault analysis; A signal generating device: connected to the supervision computing platform to detect the signal strength; When the signal strength between the signal generating device and the supervision computing platform is higher than the set threshold, the fault recording device transmits the detected data to the supervision computing platform through the signal generating device. The supervision computing platform determines the fault type based on the data and estimates the fault occurrence distance using the corresponding algorithm according to the fault type; When the signal strength between the signal generating device and the supervision computing platform is lower than the set threshold, the signal generating device transmits the data to the data processing module. The data processing module integrates and conveys the data to be stored in the data memory; Workers arrive at the scene and establish a wired data connection with the data memory, read the data in the data memory, determine the fault type based on the read data, and estimate the fault occurrence distance using the corresponding algorithm according to the fault type; The data processing module and the supervision computing platform integrate a hierarchical transmission algorithm. When the signal strength between the signal generating device and the supervision computing platform is lower than the set threshold, the hierarchical transmission algorithm processes the data integrated into the data memory and then transmits it to the supervision computing platform through the signal generating device.

2. The fault detection and rapid location system for a distribution network according to claim 1, characterized in that: The fault types include single-phase grounding fault, two-phase short-circuit fault, two-phase short-circuit grounding fault, and three-phase short-circuit fault; When it is determined to be a single-phase grounding fault, the following formula is used to calculate the fault distance: When it is determined to be a two-phase short-circuit fault, the following formula is used to calculate the fault distance: When it is determined to be a two-phase short-circuit grounding fault, the following formula is used to calculate the fault distance: When it is determined to be a three-phase short-circuit fault, the following formula is used to calculate the fault distance: Where: d is the fault distance; Z line is the wave impedance of the line; is the system frequency; is the voltage at the fault point; U1 is the positive-sequence voltage; I1 is the positive-sequence current; is the negative-sequence voltage between two phases after the fault; U2 is the steady-state negative-sequence voltage before the fault; Z1, Z2, and Z0 are the positive-sequence, negative-sequence, and zero-sequence impedances of the fault point, respectively.

3. The fault detection and rapid location system for a distribution network according to claim 1, characterized in that: The hierarchical transmission algorithm includes: S1. File Splitting and Numbering: Assume the file is F with size S; determine the data block size B; the number of data blocks For the i-th data block Fi in file F i (0 ≤ i < N), its size is B i ; when i < N - 1, B i = B; when i = N - 1, B i = S - (N - 1)B; assign a unique identifier ID i and priority P i to each data block, where the priority can be determined based on the position of the data block in the file and the importance of its content; S2. Checksum calculation: Calculate the checksum value of the data block using multiple checksum algorithms. Suppose there are m checksum algorithms used, which are C j (F i ), where j = 1, 2,..., m; Define the comprehensive checksum where w j is the weight of each checksum algorithm, satisfying S3. Transmission strategy: Determine the transmission order according to the data block priority and the current network condition. Let the network condition evaluation index be Q, which can be determined by measuring network bandwidth, latency, and packet loss rate; Define the transmission priority function where is a function adjusted according to the network condition; Sort the data blocks in descending order of the transmission priority TP i and transmit them S4. Feedback mechanism: After receiving the data block, the receiving end calculates the comprehensive checksum C' of the received data block total (F i ); If C' total (F i ) = C total (F i ), the receiving end sends an acknowledgement message ACK to the sending end and feedbacks the current network status parameters; If they are not equal, a request for retransmission message NACK is sent; The sending end adjusts the transmission strategy according to the network status feedback by the receiving end; S5. File Reorganization: The receiving end stores the received data blocks in sequence in the temporary storage area according to the identifier ID i ; after receiving all the data blocks, the data blocks are reorganized into the original file F in the order of the identifiers. Let the reorganized file be F', then where ∪ represents the merge operation.

4. A distribution network fault detection and rapid location system according to claim 1, characterized in that: The handheld computing terminal includes a processor module, a battery module, and a display screen. The battery module is used to supply power to the processor module and the display screen. After the handheld computing terminal establishes a wired data connection with the data memory, the processor module can read the data in the data memory, determine the fault type, and estimate the fault occurrence distance using the corresponding algorithm according to the fault type, and then display it on the handheld computing terminal through the display screen.

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