Power distribution network breakage fault diagnosis method and device based on distributed power source response feature identification, storage medium, terminal and electronic equipment

Abstract

The application relates to the technical field of power distribution network automation, and is a power distribution network broken line fault diagnosis method and device based on distributed power source response feature identification, a storage medium, a terminal and electronic equipment; the device comprises a data acquisition unit, a current judgment unit, a first response unit, a voltage judgment unit, a second response unit, a sudden change judgment unit, a third response unit and a broken line judgment unit; the application can adapt to intelligent diagnosis of a power distribution network broken line fault in a high-proportion distributed power source access scene, abandon traditional criteria which depend on single current disappearance, and instead comprehensively utilize rich response features of distributed power sources which are accessed to the power distribution network under broken line fault disturbance; the application solves the technical bottleneck that traditional broken line protection methods are invalid due to distributed power source access, significantly improves the accuracy, reliability and adaptability of active power distribution network broken line fault diagnosis, and effectively guarantees the safe, stable and efficient operation of an intelligent power distribution network.

Description

Technical Field

[0001] This invention relates to the field of distribution network automation technology, and in particular to a method, device, storage medium, terminal and electronic equipment for diagnosing distribution network disconnection faults based on distributed power source response characteristic identification. Background Technology

[0002] Distribution network outage detection is a core component of modern power system safety operation and maintenance, playing a crucial role in ensuring power supply reliability, maintaining public safety, and improving energy efficiency. As the "last mile" of power transmission, the distribution network directly connects to end users. Outages can cause localized power outages, impacting residents' lives, industrial production, and socio-economic activities. They can also trigger secondary disasters such as electric shocks and fires, seriously threatening the lives and property of the public. Through rapid and accurate fault detection technology, maintenance personnel can quickly locate the fault point, promptly isolate the faulty section, and initiate power restoration measures, significantly shortening outage time and reducing economic losses.

[0003] Traditional distribution networks, lacking distributed generation, are "passive" distribution networks, making line breakage faults easily identifiable. Specifically, the presence of a line breakage can be determined by checking for current in a particular phase of the distribution line, or by checking for current in a particular phase at multiple monitoring points along the line. This also allows for pinpointing the location of the fault. However, with the rapid development of new energy sources and distributed generation technologies, the penetration rate of distributed generation in distribution networks is gradually increasing, and traditional distribution networks are transforming into active distribution networks. In active distribution networks, because distributed generation is connected to the lines, it can continue to supply power to downstream lines, altering the characteristics of line breakage faults in traditional distribution networks. This means that current can still flow in the phase where the line breakage is located at the monitoring point, rendering traditional line breakage fault diagnosis methods ineffective. Summary of the Invention

[0004] This invention provides a method, device, storage medium, terminal, and electronic equipment for diagnosing distribution network open circuit faults based on distributed power source response characteristic identification. It overcomes the shortcomings of the prior art and can effectively solve the problem that existing methods that determine the open circuit fault by judging whether there is current on a certain phase of the distribution network line cannot accurately determine the open circuit fault.

[0005] To address the above problems, one of the technical solutions of this invention is implemented through the following method: a method for diagnosing distribution network line disconnection faults based on distributed generation response characteristics, comprising the following steps:

[0006] Real-time data collection of distribution network data at multiple distribution transformer monitoring points, including three-phase voltage, three-phase current, instantaneous active power, and instantaneous reactive power at the monitoring points;

[0007] A current-start criterion is constructed to determine whether the three-phase current at the monitoring point meets the current-start criterion. The current-start criterion includes the Yy current-start criterion and the Dy current-start criterion.

[0008] Therefore, flag bit variables for each monitoring point are constructed accordingly for multiple distribution transformer monitoring points;

[0009] A voltage response criterion is constructed to determine whether the three-phase voltage at the monitoring point meets the voltage response criterion. The voltage response criterion includes the Yy voltage response criterion and the Dy voltage response criterion.

[0010] In response, it is determined that the distribution transformer and the monitoring point are located downstream of the open circuit fault, and the value of the flag bit variable corresponding to the monitoring point is changed to 1;

[0011] Construct a sudden change criterion, that is, calculate the sudden change coefficient and determine whether the sudden change coefficient is greater than the set sudden change threshold;

[0012] In response, it is determined that the distribution transformer and the monitoring point are located downstream of the open circuit fault, and the value of the flag bit variable corresponding to the monitoring point is changed to 1;

[0013] Calculate the line break location variable for each monitoring point and determine whether the line break location variable is equal to 1;

[0014] Therefore, it is determined that the disconnection fault is located between the monitoring point where the disconnection location variable is equal to 1 and the monitoring point before that monitoring point.

[0015] The aforementioned power distribution network transformer monitoring points include:

[0016] The distribution transformers connected to the 10kV distribution network are numbered sequentially according to their distance from the beginning of the 10kV line: Distribution Transformer 1, Distribution Transformer 2, Distribution Transformer 3, ..., Distribution Transformer m ;in, m This represents the total number of distribution transformers on this line.

[0017] Signal monitoring points are configured on the low-voltage side of these distribution transformers, and are sequentially numbered as Monitoring Point 1, Monitoring Point 2, Monitoring Point 3, ..., Monitoring Point m .

[0018] The above-mentioned Yy current-initiated criteria and Dy current-initiated criteria include:

[0019] The Yy current-initiated criterion is shown in the following formula:

[0020] ,

[0021] The current-driven start-up criterion for Dy is shown in the following formula:

[0022] ,

[0023] In the formula, I A , I B , I C These are the effective values ​​of the currents in phases A, B, and C measured at the monitoring point at the current moment, respectively. I pA , I pB , I pC These are the effective values ​​of the currents in phases A, B, and C measured at the monitoring point 0.04 seconds before the current time; I N This refers to the rated current of the distribution transformer; The first error threshold; This is the second error threshold; This is an operation to find the minimum value of the data within the parentheses; This is an operation to find the maximum value of the data within the parentheses.

[0024] The above-mentioned Yy voltage response criteria and Dy voltage response criteria include:

[0025] The voltage response criterion for Yy is shown in the following equation:

[0026] ,

[0027] In the formula, U A , U B , U C These are the effective values ​​of the voltages of phase A, phase B, and phase C measured at the monitoring point at the current moment; These represent the phases of the A-phase, B-phase, and C-phase voltages measured at the monitoring point at the current moment; These are the phases of the A-phase, B-phase, and C-phase voltages measured at the monitoring point 0.04 seconds before the current time; U N This refers to the rated voltage of the distribution transformer.

[0028] The voltage response criterion for Dy is shown in the following equation:

[0029] ,

[0030] In the formula, U pA , UpB , U pC These are the effective values ​​of the voltages of phase A, phase B, and phase C measured at the monitoring point 0.04 seconds before the current time.

[0031] The above calculation of the sudden change coefficients includes:

[0032] Calculate the standard deviation of instantaneous active power before the line break fault. and the standard deviation of instantaneous reactive power before the line breakage fault. The calculation formula is as follows:

[0033] ,

[0034] In the formula, t 0 represents the time when the disconnection fault occurred. The time interval for the monitoring point to sample the signal. d This represents the total number of times the monitoring point samples the signal within one power frequency cycle. i To accumulate the sequence number; for The sum of the instantaneous active power of the three phases A, B, and C at the monitoring point at all times; for The sum of the instantaneous reactive power of the three phases A, B, and C at each monitoring point; This represents the average instantaneous active power before the line breakage fault; This represents the average instantaneous reactive power before the line breakage fault.

[0035] in, and The calculation formula is as follows:

[0036] ,

[0037] Calculate the standard deviation of instantaneous active power after a line break fault. and the standard deviation of instantaneous reactive power after a line break fault. The calculation method is as follows:

[0038] ,

[0039] In the formula, for The sum of the instantaneous active power of the three phases A, B, and C at the monitoring point at all times; for The sum of the instantaneous reactive power of the three phases A, B, and C at each monitoring point; This represents the average instantaneous active power after a line breakage fault; This represents the average instantaneous reactive power after a line breakage fault;

[0040] in, and The calculation formula is as follows:

[0041] ,

[0042] sudden change coefficient The calculation formula is as follows:

[0043] .

[0044] The above calculation of the line break location variables for each monitoring point includes:

[0045] The line break location variables for each monitoring point are calculated using the following formula. W 1. W 2. W 3. ... W k …、 W m :

[0046] ,

[0047] In the formula, k This is a serial number variable, and its value corresponds to the number of the monitoring point. G k and G k-1 monitoring points k and monitoring points k -1 is a flag variable.

[0048] The second technical solution of the present invention is achieved through the following means: a distribution network open-circuit fault diagnosis device based on distributed source response characteristic identification, wherein the device uses a distribution network open-circuit fault diagnosis method based on distributed source response characteristic identification, comprising:

[0049] The data acquisition unit collects distribution network data in real time from multiple distribution transformer monitoring points. The distribution network data includes three-phase voltage, three-phase current, instantaneous active power, and instantaneous reactive power at the monitoring points.

[0050] The current judgment unit constructs the current start criterion and determines whether the three-phase current at the monitoring point meets the current start criterion. The current start criterion includes the Yy current start criterion and the Dy current start criterion.

[0051] The first response unit, in response to this, then constructs the flag bit variables for each monitoring point of the multiple distribution transformer monitoring points accordingly;

[0052] The voltage judgment unit constructs voltage response criteria to determine whether the three-phase voltage at the monitoring point meets the voltage response criteria. The voltage response criteria include the Yy voltage response criteria and the Dy voltage response criteria.

[0053] The second response unit then determines that the distribution transformer and the monitoring point are located downstream of the open circuit fault and changes the value of the flag bit variable corresponding to the monitoring point to 1.

[0054] The sudden change judgment unit constructs the sudden change criterion, that is, it calculates the sudden change coefficient and judges whether the sudden change coefficient is greater than the set sudden change threshold.

[0055] The third response unit then determines that the distribution transformer and the monitoring point are located downstream of the open circuit fault and changes the value of the flag bit variable corresponding to the monitoring point to 1.

[0056] The disconnection judgment unit calculates the disconnection location variable for each monitoring point and determines whether the disconnection location variable is equal to 1.

[0057] The fourth response unit then determines that the disconnection fault is located between the monitoring point where the disconnection location variable is equal to 1 and the monitoring point before that monitoring point.

[0058] The third technical solution of the present invention is achieved by the following means: a storage medium storing a computer program that can be read by a computer, the computer program being configured to execute a method for diagnosing distribution network disconnection faults based on distributed power source response characteristics during runtime.

[0059] The fourth technical solution of the present invention is implemented in the following way: a terminal, including a processor, a memory, a communication interface, and one or more programs, wherein the one or more programs are stored in the memory and configured to be executed by the processor, and the programs include instructions for performing steps in the method for diagnosing distribution network disconnection faults based on distributed power source response characteristics.

[0060] The fifth technical solution of the present invention is achieved in the following way: an electronic device, including a processor and a memory, wherein the memory stores a computer program, and the computer program is loaded and executed by the processor to realize a method for diagnosing distribution network disconnection faults based on distributed power source response characteristics.

[0061] Compared with the prior art, the present invention has the following advantages:

[0062] This invention constructs a multi-level, adaptive, and highly reliable identification criterion system by real-time acquisition of voltage, current, and power information from low-voltage side monitoring points of each distribution transformer along a power line. The method first rapidly detects fault occurrence by analyzing the initiation criterion based on current surge characteristics. Then, based on the different connection groups of the distribution transformers (Yy or Dy), precise voltage response criterions are designed to identify the unique voltage amplitude and phase change patterns at downstream monitoring points. Furthermore, to address the special scenario where downstream of the fault involves grid-type distributed power sources and insignificant voltage changes, this invention also introduces an auxiliary criterion based on the power surge coefficient, identifying the downstream fault region by analyzing the significant difference in the standard deviation of active and reactive power before and after the fault. Finally, by comprehensively considering the status indicators of each monitoring point, the section where the line break fault is located can be accurately determined.

[0063] This invention enables intelligent diagnosis of distribution network line breakage faults in scenarios with a high proportion of distributed power sources. It abandons the traditional criterion of relying on the disappearance of a single current and instead comprehensively utilizes the rich response characteristics exhibited by distributed power sources connected to the distribution network under line breakage disturbances. This invention solves the technical bottleneck of the failure of traditional line breakage protection methods caused by the access of distributed power sources, significantly improves the accuracy, reliability and adaptability of fault diagnosis of line breakage faults in active distribution networks, and effectively ensures the safe, stable and efficient operation of smart distribution networks. Attached Figure Description

[0064] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings.

[0065] Figure 1 This is a flowchart of the method in Embodiment 1 of the present invention.

[0066] Figure 2 This is the voltage phasor diagram of the low-voltage side of the distribution transformer in the Yy connection method of Embodiment 2 of the present invention.

[0067] Figure 3 This is the voltage phasor diagram of the low-voltage side of the distribution transformer in the Dy connection method of Embodiment 2 of the present invention.

[0068] Figure 4 This is a block diagram of the device structure in Embodiment 3 of the present invention.

[0069] Figure 5 This is a histogram of the interruption line location variables in Embodiment 4 of the present invention. Detailed Implementation

[0070] The present invention is not limited to the following embodiments, and the specific implementation can be determined according to the technical solution of the present invention and the actual situation.

[0071] Example 1: As Figure 1As shown in the figure, this invention discloses a method for diagnosing distribution network line breakage faults based on distributed generation response characteristics, including the following steps:

[0072] Step S101: Real-time acquisition of distribution network data at multiple distribution transformer monitoring points, including three-phase voltage, three-phase current, instantaneous active power and instantaneous reactive power at the monitoring points;

[0073] Step S102: Construct current start criteria to determine whether the three-phase current at the monitoring point meets the current start criteria. The current start criteria include Yy current start criteria and Dy current start criteria.

[0074] In step S103, in response, flag bit variables for each monitoring point are constructed accordingly for multiple distribution transformer monitoring points;

[0075] Step S104: Construct voltage response criteria to determine whether the three-phase voltage at the monitoring point meets the voltage response criteria. The voltage response criteria include the Yy voltage response criteria and the Dy voltage response criteria.

[0076] In step S105, the response is that the distribution transformer and the monitoring point are located downstream of the open circuit fault, and the value of the flag bit variable corresponding to the monitoring point is changed to 1.

[0077] Step S106: Construct a sudden change criterion, that is, calculate the sudden change coefficient and determine whether the sudden change coefficient is greater than the set sudden change threshold.

[0078] In step S107, the response is that the distribution transformer and the monitoring point are located downstream of the open circuit fault, and the value of the flag bit variable corresponding to the monitoring point is changed to 1.

[0079] Step S108: Calculate the disconnection location variable for each monitoring point and determine whether the disconnection location variable is equal to 1;

[0080] In step S109, the response is that the disconnection fault is located between the monitoring point where the disconnection location variable is equal to 1 and the monitoring point before the monitoring point.

[0081] In step S101 above, the monitoring points for distribution network transformers include:

[0082] The distribution transformers connected to the 10kV distribution network are numbered sequentially according to their distance from the beginning of the 10kV line: Distribution Transformer 1, Distribution Transformer 2, Distribution Transformer 3, ..., Distribution Transformer m ;in, m This represents the total number of distribution transformers on this line.

[0083] Signal monitoring points are configured on the low-voltage side of these distribution transformers, and are sequentially numbered as Monitoring Point 1, Monitoring Point 2, Monitoring Point 3, ..., Monitoring Point m .

[0084] In step S102 above, the Yy current initiation criterion and the Dy current initiation criterion include:

[0085] The Yy current-initiated criterion is shown in the following formula:

[0086] ,

[0087] The current-driven start-up criterion for Dy is shown in the following formula:

[0088] ,

[0089] In the formula, I A , I B , I C These are the effective values ​​of the currents in phases A, B, and C measured at the monitoring point at the current moment, respectively. I pA , I pB , I pC These are the effective values ​​of the currents in phases A, B, and C measured at the monitoring point 0.04 seconds before the current time; I N This refers to the rated current of the distribution transformer; The first error threshold; This is the second error threshold; This is an operation to find the minimum value of the data within the parentheses; This is an operation to find the maximum value of the data within the parentheses.

[0090] In step S102 above, a current start criterion is constructed to determine whether the three-phase current at the monitoring point meets the current start criterion. The current start criterion includes the Yy current start criterion and the Dy current start criterion. If no, it is determined that there is no open circuit fault, and the process returns to step S101.

[0091] The preferred first error threshold described above The value is taken as 3 times the maximum relative measurement error of the monitoring point; the second error threshold. The value is 0.15.

[0092] The distribution transformers are connected in two ways: Yy (star connection) and Dy (delta connection). A Yy current initiation criterion is constructed for the Yy connection and a Dy current initiation criterion is constructed for the Dy connection. Both the Yy and Dy current initiation criteria are constructed based on the effective values ​​of the three-phase currents measured at the current time and 0.04 seconds before the current time at the monitoring point, and their ratio. Once the three-phase current at any monitoring point meets the Yy or Dy current initiation criterion, it is determined that a line break fault has occurred, and the time of the line break fault is recorded.

[0093] This invention constructs Yy current initiation criteria and Dy current initiation criteria. When a wire breakage fault occurs, the current at the monitoring point will change abruptly. This invention constructs Yy current initiation criteria and Dy current initiation criteria by capturing the relationship of the current change. Thus, assuming that a wire breakage fault has occurred, the current moment belongs to the time after the wire breakage fault occurred, and the time 0.04 seconds before the current moment belongs to the time before the wire breakage fault occurred.

[0094] Furthermore, for monitoring points corresponding to distribution transformers with Yy connection, the current in the disconnected phase rapidly decays to near zero. Since the specific disconnected phase is unknown beforehand, the Yy current initiation criterion is affected. This indicates that the current in the non-disconnected phase is affected by the voltage distribution of the distribution transformer windings. The phase voltage change of the non-disconnected phase is half of the line voltage. Correspondingly, after a disconnection fault occurs, the current decays to half of the current before the fault. Multiples; combining the current of the disconnected phase and the current of the non-disconnected phase, the Yy current starting criterion is based on... Indicates setting the first error threshold. The purpose is to eliminate error interference; at the same time, in order to eliminate the interference of no-load conditions on the algorithm, the Yy current start-up criterion is set. If the three-phase current at any monitoring point meets the Yy current start criterion, then the line is determined to have a broken line fault.

[0095] For monitoring points corresponding to distribution transformers with Dy connection, the following exists: a line break fault has a very slight impact on one phase of the current at the monitoring point, but a significant impact on the other two phases; for the phase with a very slight impact from the line break fault, since it is not known in advance which phase it is (because the phase with the broken wire is unknown), the Dy current initiation criterion is based on... This indicates that for the two phases most significantly affected by the open-circuit fault, the current in the non-open-circuit phases is affected by the voltage distribution of the distribution transformer windings, and analysis reveals that the current signal exists. Set a second error threshold. The purpose is to eliminate error interference; at the same time, in order to eliminate the interference of no-load conditions on the algorithm, the Dy current start criterion is set. If the three-phase current at any monitoring point meets the Dy current start criterion, then the line is determined to have a broken line fault.

[0096] In step S103 above, the flag variable is constructed as follows: for monitoring point 1, monitoring point 2, monitoring point 3, ..., monitoring point m Accordingly, flag variables for each monitoring point are constructed. G 1. G 2. G 3, ... G m The initial values ​​of these flag variables are all 0.

[0097] In step S104 above, the Yy voltage response criteria and the Dy voltage response criteria include:

[0098] The voltage response criterion for Yy is shown in the following equation:

[0099] ,

[0100] In the formula, U A , U B , U C These are the effective values ​​of the voltages of phase A, phase B, and phase C measured at the monitoring point at the current moment; These represent the phases of the A-phase, B-phase, and C-phase voltages measured at the monitoring point at the current moment; These are the phases of the A-phase, B-phase, and C-phase voltages measured at the monitoring point 0.04 seconds before the current time; U N This refers to the rated voltage of the distribution transformer.

[0101] The voltage response criterion for Dy is shown in the following equation:

[0102] ,

[0103] In the formula, U pA , U pB , U pC These are the effective values ​​of the voltages of phase A, phase B, and phase C measured at the monitoring point 0.04 seconds before the current time.

[0104] For any monitoring point, the effective value and phase of the three-phase voltage measured at the current time and the phase of the three-phase voltage measured 0.04 seconds before the current time are collected. It is then determined whether the Yy voltage response criterion or Dy voltage response criterion is met. If the Yy voltage response criterion or Dy voltage response criterion is met, it is determined that the distribution transformer and the monitoring point are located downstream of the open circuit fault, and the value of the flag bit variable corresponding to the monitoring point is changed to 1. Otherwise, in step S104, if the response is negative, the value of the flag bit variable corresponding to the monitoring point is not changed.

[0105] In step S106 above, the sudden change coefficient is calculated, including:

[0106] Calculate the standard deviation of instantaneous active power before the line break fault. and the standard deviation of instantaneous reactive power before the line breakage fault. The calculation formula is as follows:

[0107] ,

[0108] In the formula, t 0 represents the time when the disconnection fault occurred. The time interval for the monitoring point to sample the signal. d This represents the total number of times the monitoring point samples the signal within one power frequency cycle. i To accumulate the sequence number; for The sum of the instantaneous active power of the three phases A, B, and C at the monitoring point at all times; for The sum of the instantaneous reactive power of the three phases A, B, and C at each monitoring point; This represents the average instantaneous active power before the line breakage fault; This represents the average instantaneous reactive power before the line breakage fault.

[0109] in, and The calculation formula is as follows:

[0110] ;

[0111] Calculate the standard deviation of instantaneous active power after a line break fault. and the standard deviation of instantaneous reactive power after a line break fault. The calculation method is as follows:

[0112] ,

[0113] In the formula, for The sum of the instantaneous active power of the three phases A, B, and C at the monitoring point at all times; for The sum of the instantaneous reactive power of the three phases A, B, and C at each monitoring point; This represents the average instantaneous active power after a line breakage fault; This represents the average instantaneous reactive power after a line breakage fault;

[0114] in, and The calculation formula is as follows:

[0115] ,

[0116] sudden change coefficient The calculation formula is as follows:

[0117] .

[0118] For any given monitoring point, the instantaneous active power and instantaneous reactive power flowing through the monitoring point are collected. The standard deviations of the instantaneous active power and instantaneous reactive power before and after the line break fault are calculated. The sudden change coefficient is obtained based on the ratio between the calculated standard deviations. The obtained sudden change coefficient is then judged. Does it meet the following requirements: , The set sudden change threshold; if the calculated sudden change coefficient satisfies If the fault is found, the distribution transformer and the monitoring point are determined to be downstream of the open circuit fault, and the value of the flag bit variable corresponding to the monitoring point is changed to 1; otherwise, in step S106, if the response is no, the value of the flag bit variable corresponding to the monitoring point is not changed.

[0119] In step S108 above, it is determined whether the disconnection location variable is equal to 1. If the response is no, it indicates that there is no disconnection fault between the monitoring point and the monitoring point before the monitoring point.

[0120] In step S108 above, the disconnection location variables for each monitoring point are calculated, including:

[0121] The line break location variables for each monitoring point are calculated using the following formula. W 1. W 2. W 3. ... W k …、 W m :

[0122] ,

[0123] In the formula, k This is a serial number variable, and its value corresponds to the number of the monitoring point. G k and G k-1monitoring points k and monitoring points k -1 is a flag variable.

[0124] After calculating the disconnection location variables for each monitoring point, the current situation is checked. W 1. W 2. W 3, ... W m The value; if W If 1 equals 1, then the open circuit fault can be determined to be located between monitoring point 1 and the beginning of the line; for variables s Its value can be 2 to m any integer between, W s for W 1. W 2. W 3, ... W m The first in s A broken line location variable; if W s If the value is 1, then the fault can be determined to be located at the monitoring point. s and monitoring points s Between -1 and 1.

[0125] In summary, this invention constructs a multi-level, adaptive, and highly reliable identification criterion system by real-time acquisition of voltage, current, and power information from low-voltage side monitoring points of each distribution transformer on the line. The method first rapidly detects fault occurrence by analyzing the initiation criterion of current mutation characteristics. Then, based on the different connection groups of the distribution transformers (Yy or Dy), precise voltage response criteria are designed to identify the unique voltage amplitude and phase change patterns of downstream monitoring points. Furthermore, to address the special scenario where downstream of the fault involves grid-type distributed power sources and insignificant voltage changes, this invention also introduces an auxiliary criterion based on the power surge coefficient, identifying the downstream fault region by analyzing the significant difference in the standard deviation of active and reactive power before and after the fault. Finally, by comprehensively considering the status indicators of each monitoring point, the section where the line break fault is located can be accurately determined.

[0126] Therefore, this invention can adapt to the intelligent diagnosis of distribution network line breakage faults in scenarios with a high proportion of distributed power sources connected to the network. It abandons the traditional criterion of relying on the disappearance of a single current and instead comprehensively utilizes the rich response characteristics exhibited by distributed power sources connected to the distribution network under the disturbance of line breakage faults. This invention solves the technical bottleneck of the failure of traditional line breakage protection methods caused by the connection of distributed power sources, significantly improves the accuracy, reliability and adaptability of fault diagnosis of line breakage faults in active distribution networks, and effectively ensures the safe, stable and efficient operation of smart distribution networks.

[0127] Example 2: This embodiment of the invention discloses the analysis process using a broken phase A of a line as an example:

[0128] For lines, distribution transformers, and monitoring points upstream of the fault point, the impact of the fault is minimal. However, for lines, distribution transformers, and monitoring points downstream of the fault point, the impact is significant, specifically in terms of voltage, current, and power response. This impact depends on whether there are grid-type distributed power sources or distribution transformer connections downstream of the fault point. A detailed analysis follows:

[0129] When there is no grid-type distributed power source downstream of the line break fault point, the low-voltage side voltage phasor diagram of the distribution transformer with Yy connection downstream of the line break fault point is as follows: Figure 2 As shown in the figure; These are the phase A, phase B, and phase C voltage phasors measured at the monitoring point at the current moment, respectively. These are the voltage phasors of phases A, B, and C measured at the monitoring point 0.04 seconds before the current time; at this time, the following exists:

[0130] ,

[0131] This leads to the conclusion that

[0132] ,

[0133] Considering certain measurement errors and margins, there exists

[0134] ,

[0135] Therefore, the Yy voltage response criterion is satisfied.

[0136] When there is no grid-type distributed power source downstream of the line break fault point, the low-voltage side voltage phasor diagram of the distribution transformer with Dy connection downstream of the line break fault point is as follows: Figure 3 As shown, at this time:

[0137] ,

[0138] In the formula, The calculation is to determine the active power of the two phasors in parentheses;

[0139] Expanding the left side of the equation, we get:

[0140] ,

[0141] Therefore, we get:

[0142] ,

[0143] Therefore, it can be deduced that:

[0144] ,

[0145] Considering certain measurement errors and margins, there exists

[0146] ,

[0147] Therefore, the Dy voltage response criterion is satisfied.

[0148] When phase B or phase C of the line is disconnected, the Yy voltage response criterion and the Dy voltage response criterion can still be satisfied, which will not be elaborated here.

[0149] If there is a grid-type distributed power source downstream of the line break fault point, the phase voltage change at the monitoring point of the downstream distribution transformer may be slight due to the influence of the grid-type distributed power source, making it impossible to detect the line break fault through steps S102 and S104. In this case, the line break fault can be detected through step S106 by utilizing the response of instantaneous active power and instantaneous reactive power to the line break fault under the action of the grid-type distributed power source.

[0150] Specifically, downstream of a line break fault, the instantaneous active and reactive power changes relatively little before the fault occurs, and their standard deviations are also small. However, after the fault occurs, the instantaneous active and reactive power change significantly, and their standard deviations are large, as indicated by the sudden change coefficient. The sudden change coefficient calculated using the formula is very large. However, for the upstream of the line break fault, the instantaneous active and reactive power change little before and after the fault, and the difference in standard deviation before and after the fault is not significant, resulting in a small sudden change coefficient. Therefore, the sudden change coefficient criterion can be used to determine whether the distribution transformer and the monitoring point are located downstream of the line break fault.

[0151] Example 3: As Figure 4 As shown, this invention discloses a distribution network open-circuit fault diagnosis device based on distributed source response feature identification. The device uses a distribution network open-circuit fault diagnosis method based on distributed source response feature identification, characterized by comprising:

[0152] The data acquisition unit collects distribution network data in real time from multiple distribution transformer monitoring points. The distribution network data includes three-phase voltage, three-phase current, instantaneous active power, and instantaneous reactive power at the monitoring points.

[0153] The current judgment unit constructs the current start criterion and determines whether the three-phase current at the monitoring point meets the current start criterion. The current start criterion includes the Yy current start criterion and the Dy current start criterion.

[0154] The first response unit, in response to this, then constructs the flag bit variables for each monitoring point of the multiple distribution transformer monitoring points accordingly;

[0155] The voltage judgment unit constructs voltage response criteria to determine whether the three-phase voltage at the monitoring point meets the voltage response criteria. The voltage response criteria include the Yy voltage response criteria and the Dy voltage response criteria.

[0156] The second response unit then determines that the distribution transformer and the monitoring point are located downstream of the open circuit fault and changes the value of the flag bit variable corresponding to the monitoring point to 1.

[0157] The sudden change judgment unit constructs the sudden change criterion, that is, it calculates the sudden change coefficient and judges whether the sudden change coefficient is greater than the set sudden change threshold.

[0158] The third response unit then determines that the distribution transformer and the monitoring point are located downstream of the open circuit fault and changes the value of the flag bit variable corresponding to the monitoring point to 1.

[0159] The disconnection judgment unit calculates the disconnection location variable for each monitoring point and determines whether the disconnection location variable is equal to 1.

[0160] The fourth response unit then determines that the disconnection fault is located between the monitoring point where the disconnection location variable is equal to 1 and the monitoring point before that monitoring point.

[0161] Example 4: To verify the effectiveness and reliability of the present invention, a line break fault simulation model was built. The line break fault simulation model includes 5 monitoring points; the distribution transformers corresponding to the first three monitoring points adopt a Yy connection method, and the others adopt a Dy connection method; an A-phase break fault is set between the second and third monitoring points. Simulation signals and data were obtained after the simulation was implemented. The specific implementation process is as follows:

[0162] Step 1: Number the distribution transformers and monitoring points connected to the 10kV distribution network; for each monitoring point, number them sequentially as Monitoring Point 1, Monitoring Point 2, Monitoring Point 3, Monitoring Point 4, and Monitoring Point 5; collect the A, B, and C three-phase voltages and A, B, and C three-phase currents, as well as the instantaneous active power and instantaneous reactive power at these monitoring points in real time;

[0163] Step 2: Based on the effective values ​​of the three-phase currents measured at the current time and 0.04 seconds before the current time at the monitoring points, and their ratios, construct the Yy current initiation criterion and the Dy current initiation criterion for distribution transformers with Yy connection and Dy connection, respectively. The three-phase current at monitoring point 3 meets the Yy current initiation criterion; the three-phase currents at monitoring points 4 and 5 meet the Dy current initiation criterion. It can be determined that a line break fault has occurred, and the time of the line break fault is recorded.

[0164] Step 3: For monitoring points 1, 2, 3, 4, and 5, construct the corresponding flag variables for each monitoring point. G 1. G 2. G 3. G 4. G 5; The initial values ​​of these flag variables are all 0;

[0165] Step 4: Further, for any monitoring point, collect the effective value and phase of the three-phase voltage measured at the current time of the monitoring point, and the phase of the three-phase voltage measured 0.04 seconds before the current time, and determine whether it meets the Yy voltage response criterion.

[0166] In the simulation of a distributed power source without a network downstream of a line break fault, the monitoring point 3 satisfies the Yy voltage response criterion, indicating that the distribution transformer and the monitoring point are located downstream of the line break fault, and the value of the flag bit variable corresponding to the monitoring point is changed to 1.

[0167] Step 5: Further, for any monitoring point, collect the effective value and phase of the three-phase voltage measured at the current time and the effective value and phase of the three-phase voltage measured 0.04 seconds before the current time, and determine whether it meets the Dy voltage response criterion;

[0168] In the simulation of a distributed power source without a network downstream of a line break fault, monitoring points 4 and 5 meet the Dy voltage response criterion, indicating that the distribution transformer and the monitoring point are located downstream of the line break fault, and the value of the flag bit variable corresponding to the monitoring point is changed to 1.

[0169] Step 6: Further, for any monitoring point, collect the instantaneous active power and instantaneous reactive power flowing through the monitoring point, calculate the standard deviation of the instantaneous active power and instantaneous reactive power before and after the line break fault, and obtain the sudden change coefficient based on the ratio between the obtained standard deviations.

[0170] In the simulation of a structured grid-type distributed power source downstream of a line break fault, the sudden change coefficients obtained at monitoring points 3, 4, and 5 satisfy the criterion for sudden change coefficients, indicating that the distribution transformer and the monitoring point are located downstream of the line break fault, and the value of the flag bit variable corresponding to the monitoring point is changed to 1.

[0171] Step 7: Calculate the line break location variables at each monitoring point. W 1. W 2. W 3. W 4. W 5: Flag variables and the obtained break location variables, such as Figure 5 As shown in the bar chart;

[0172] Step 8: Check at this time W 1. W 2. W 3, ... W m The value at this time; W If 3 equals 1, it can be determined that the disconnection fault is located between monitoring point 2 and monitoring point 3.

[0173] Therefore, this embodiment verifies the effectiveness and reliability of the technology of the present invention.

[0174] Example 5: This embodiment of the invention discloses a storage medium storing a computer program that can be read by a computer. The computer program is configured to execute a method for diagnosing distribution network disconnection faults based on distributed power source response characteristic identification when it runs.

[0175] The aforementioned storage media may include, but are not limited to, USB flash drives, read-only memory, portable hard drives, magnetic disks, optical disks, and other media capable of storing computer programs.

[0176] Example 6: This embodiment of the invention discloses a terminal, including a processor, a memory, a communication interface, and one or more programs. The one or more programs are stored in the memory and configured to be executed by the processor. The programs include instructions for performing steps in the method for diagnosing distribution network disconnection faults based on distributed power source response characteristics.

[0177] Example 7: This embodiment of the invention discloses an electronic device, including a processor and a memory. The memory stores a computer program, which is loaded and executed by the processor to implement a method for diagnosing power distribution network disconnection faults based on distributed power source response characteristics.

[0178] The aforementioned electronic device also includes transmission devices and input / output devices, wherein both the transmission devices and the input / output devices are connected to the processor.

[0179] The processor described above can be a central processing unit (CPU), a general-purpose processor, a digital signal processor (DSP), an ASIC, an FPGA, or other programmable logic devices, transistor logic devices, hardware components, or any combination thereof. It can implement or execute the various exemplary logic blocks, modules, and circuits described in conjunction with the disclosure of this application. It can also be a combination that implements computational functions, such as a combination of one or more microprocessors, a combination of a DSP and a microprocessor, etc. The memory can include, but is not limited to, various media capable of storing computer programs, such as USB flash drives, read-only memory, portable hard drives, magnetic disks, or optical disks.

[0180] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code. The solutions in the embodiments of this application can be implemented in various computer languages, such as the object-oriented programming language Java and the interpreted scripting language JavaScript.

[0181] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0182] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0183] This application also provides a computer program product, which includes a non-transitory computer-readable storage medium storing a computer program operable to cause a computer to perform some or all of the steps of any of the methods described in the above method embodiments. The computer program product may be a software installation package, and the computer may include an electronic device.

Claims

1. A method for diagnosing distribution network line break faults based on distributed generation response characteristics, characterized in that, Includes the following steps: Real-time data collection of distribution network data at multiple distribution transformer monitoring points, including three-phase voltage, three-phase current, instantaneous active power, and instantaneous reactive power at the monitoring points; A current-start criterion is constructed to determine whether the three-phase current at the monitoring point meets the current-start criterion. The current-start criterion includes the Yy current-start criterion and the Dy current-start criterion. Therefore, flag bit variables for each monitoring point are constructed accordingly for multiple distribution transformer monitoring points; A voltage response criterion is constructed to determine whether the three-phase voltage at the monitoring point meets the voltage response criterion. The voltage response criterion includes the Yy voltage response criterion and the Dy voltage response criterion. In response, it is determined that the distribution transformer and the monitoring point are located downstream of the open circuit fault, and the value of the flag bit variable corresponding to the monitoring point is changed to 1; Construct a sudden change criterion, that is, calculate the sudden change coefficient and determine whether the sudden change coefficient is greater than the set sudden change threshold; In response, it is determined that the distribution transformer and the monitoring point are located downstream of the open circuit fault, and the value of the flag bit variable corresponding to the monitoring point is changed to 1; Calculate the line break location variable for each monitoring point and determine whether the line break location variable is equal to 1; Therefore, it is determined that the disconnection fault is located between the monitoring point where the disconnection location variable is equal to 1 and the monitoring point before that monitoring point.

2. The method for diagnosing distribution network line breakage faults based on distributed source response characteristic identification according to claim 1, characterized in that, The real-time acquisition of distribution network data from multiple distribution transformer monitoring points includes: The distribution transformers connected to the 10kV distribution network are numbered sequentially according to their distance from the beginning of the 10kV line: Distribution Transformer 1, Distribution Transformer 2, Distribution Transformer 3, ..., Distribution Transformer m ;in, m This represents the total number of distribution transformers on this line. Signal monitoring points are configured on the low-voltage side of these distribution transformers, and are sequentially numbered as Monitoring Point 1, Monitoring Point 2, Monitoring Point 3, ..., Monitoring Point m .

3. The method for diagnosing distribution network line breakage faults based on distributed source response characteristic identification according to claim 1, characterized in that, The Yy current-initiated criterion and the Dy current-initiated criterion include: The Yy current-initiated criterion is shown in the following formula: ， The current-driven start-up criterion for Dy is shown in the following formula: ， In the formula, I A , I B , I C These are the effective values ​​of the currents in phases A, B, and C measured at the monitoring point at the current moment, respectively. I pA , I pB , I pC These are the effective values ​​of the currents in phases A, B, and C measured at the monitoring point 0.04 seconds before the current time; I N This refers to the rated current of the distribution transformer; The first error threshold; This is the second error threshold; This is an operation to find the minimum value of the data within the parentheses; This is an operation to find the maximum value of the data within the parentheses.

4. The method for diagnosing distribution network line breakage faults based on distributed source response characteristic identification according to claim 1, characterized in that, The Yy voltage response criteria and Dy voltage response criteria include: The voltage response criterion for Yy is shown in the following equation: ， In the formula, U A , U B , U C These are the effective values ​​of the voltages of phase A, phase B, and phase C measured at the monitoring point at the current moment; These represent the phases of the A-phase, B-phase, and C-phase voltages measured at the monitoring point at the current moment; These are the phases of the A-phase, B-phase, and C-phase voltages measured at the monitoring point 0.04 seconds before the current time; U N This refers to the rated voltage of the distribution transformer. The voltage response criterion for Dy is shown in the following equation: ， In the formula, U pA , U pB , U pC These are the effective values ​​of the voltages of phase A, phase B, and phase C measured at the monitoring point 0.04 seconds before the current time.

5. The method for diagnosing distribution network line breakage faults based on distributed source response characteristic identification according to claim 1, characterized in that, The determination of the sudden change coefficient includes: Calculate the standard deviation of instantaneous active power before the line break fault. and the standard deviation of instantaneous reactive power before the line breakage fault. The calculation formula is as follows: ， In the formula, t 0 represents the time when the disconnection fault occurred. The time interval for the monitoring point to sample the signal. d This represents the total number of times the monitoring point samples the signal within one power frequency cycle. i To accumulate the sequence number; for The sum of the instantaneous active power of the three phases A, B, and C at the monitoring point at all times; for The sum of the instantaneous reactive power of the three phases A, B, and C at each monitoring point; This represents the average instantaneous active power before the line breakage fault; This represents the average instantaneous reactive power before the line breakage fault. in, and The calculation formula is as follows: ， Calculate the standard deviation of instantaneous active power after a line break fault. and the standard deviation of instantaneous reactive power after a line break fault. The calculation method is as follows: ， In the formula, for The sum of the instantaneous active power of the three phases A, B, and C at the monitoring point at all times; for The sum of the instantaneous reactive power of the three phases A, B, and C at each monitoring point; This represents the average instantaneous active power after a line breakage fault; This represents the average instantaneous reactive power after a line breakage fault; in, and The calculation formula is as follows: ， sudden change coefficient The calculation formula is as follows: 。 6. The method for diagnosing distribution network line breakage faults based on distributed source response characteristic identification according to claim 1, characterized in that, The calculation of the disconnection location variables for each monitoring point includes: The line break location variables for each monitoring point are calculated using the following formula. W 1. W 2. W 3. ... W k …、 W m : ， In the formula, k This is a serial number variable, and its value corresponds to the number of the monitoring point. G k and G k-1 monitoring points k and monitoring points k -1 is a flag variable.

7. A distribution network open-circuit fault diagnosis device based on distributed source response feature identification, wherein the device uses the distribution network open-circuit fault diagnosis method based on distributed source response feature identification as described in any one of claims 1 to 6, characterized in that, include: The data acquisition unit collects distribution network data in real time from multiple distribution transformer monitoring points. The distribution network data includes three-phase voltage, three-phase current, instantaneous active power, and instantaneous reactive power at the monitoring points. The current judgment unit constructs the current start criterion and determines whether the three-phase current at the monitoring point meets the current start criterion. The current start criterion includes the Yy current start criterion and the Dy current start criterion. The first response unit, in response to this, then constructs the flag bit variables for each monitoring point of the multiple distribution transformer monitoring points accordingly; The voltage judgment unit constructs voltage response criteria to determine whether the three-phase voltage at the monitoring point meets the voltage response criteria. The voltage response criteria include the Yy voltage response criteria and the Dy voltage response criteria. The second response unit then determines that the distribution transformer and the monitoring point are located downstream of the open circuit fault and changes the value of the flag bit variable corresponding to the monitoring point to 1. The sudden change judgment unit constructs the sudden change criterion, that is, it calculates the sudden change coefficient and judges whether the sudden change coefficient is greater than the set sudden change threshold. The third response unit then determines that the distribution transformer and the monitoring point are located downstream of the open circuit fault and changes the value of the flag bit variable corresponding to the monitoring point to 1. The disconnection judgment unit calculates the disconnection location variable for each monitoring point and determines whether the disconnection location variable is equal to 1. The fourth response unit then determines that the disconnection fault is located between the monitoring point where the disconnection location variable is equal to 1 and the monitoring point before that monitoring point.

8. A storage medium, characterized in that, The storage medium stores a computer program that can be read by a computer, and the computer program is configured to execute the method for diagnosing distribution network disconnection faults based on distributed power source response feature identification as described in any one of claims 1 to 6 when it runs.

9. A terminal, characterized in that, The system includes a processor, a memory, a communication interface, and one or more programs, which are stored in the memory and configured to be executed by the processor. The programs include instructions for performing the steps in the method for diagnosing distribution network disconnection faults based on distributed power source response characteristics as described in any one of claims 1 to 6.

10. An electronic device, characterized in that, It includes a processor and a memory, wherein the memory stores a computer program, which is loaded and executed by the processor to implement the method for diagnosing distribution network disconnection faults based on distributed power source response characteristic identification as described in any one of claims 1 to 6.

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