A method and system for auxiliary decision-making in single-phase ground fault substations using the circuit-based approach.

Abstract

This invention relates to a method and system for auxiliary decision-making in substations with single-phase grounding faults using the pull-loop method. The system includes: a pull-loop auxiliary decision-making data cloud; a fault SMS notification receiving module for sending first fault information to the pull-loop auxiliary decision-making data cloud; and a fault local analysis module, distributedly installed at the feeder distribution line bays and / or the low-voltage side bays of the main transformer, which, upon detecting a single-phase grounding fault below, sends second and / or third fault information corresponding to the installation location to the pull-loop auxiliary decision-making data cloud. The method includes: constructing a fault set based on the Lx distribution line according to the first fault information to obtain an external-Lx distribution line fault set B; determining the information result of the second fault information; and performing probability calculations on the information result and the external-Lx distribution line fault set B using different mathematical weights to calculate the comprehensive probability of a single-phase grounding fault in the Lx distribution line using a fault occurrence probability calculation method.

Description

Technical Field

[0001] This invention relates to the field of single-phase grounding fault handling technology in power distribution networks, and in particular to a circuit-based auxiliary decision-making method and system for single-phase grounding fault substations. Background Technology

[0002] Currently, in many municipal power companies' 110kV and below substations, when a single-phase ground fault occurs on a distribution line (usually 6-35kV, typically 10kV) requiring fault clearing, the municipal power company's dispatch department (local dispatch) uses a circuit-pulling method to locate the fault based on fault information reported by the substation's telemetry, remote signaling, and low-current ground fault location devices. However, the low-current ground fault location devices often have inaccurate fault selection, and the local dispatch operation and management personnel mainly rely on the circuit-pulling method (the method of sequentially pulling circuits) to confirm the fault until it disappears. Therefore, the time required to locate a single-phase ground fault is often long. Plugging non-faulty lines will cause a short-term power outage, and it is very likely that the circuit-pulling method will fail to clear the fault simply because a single-phase ground fault occurs on the busbar (such as a busbar grounding caused by a damaged surge arrester). At the same time, the entire substation's feeder lines will experience a short-term power outage and restoration, which seriously reduces the power supply reliability of the power company's distribution lines, adversely affects the user's power experience, and is prone to complaints.

[0003] CN102788933A discloses a method for locating small-current single-phase ground faults in a power grid using an automatic circuit breaker controller. The specific steps of this invention are as follows: (1) compiling and importing a circuit breaker sequence list; (2) determining whether a small-current single-phase ground fault has occurred; (3) when a small-current single-phase ground fault occurs, the automatic circuit breaker controller performs a trial circuit breaker.

[0004] With the increasing coverage of various distribution terminals installed on distribution automation systems, power company maintenance personnel will receive SMS notifications from the distribution automation system when a single-phase grounding fault occurs on a distribution line. When a substation needs to perform fault-blocking operations, dispatching and management personnel can perform these operations by communicating with maintenance personnel by phone and based on fault information reported by users, combined with routine telemetry and telecontrol data from the substation. However, uncertainties remain due to factors such as disorganized, missing, or delayed SMS information, forcing dispatching and management personnel to rely on past experience for comprehensive information judgment. Often, they still rely on the conventional fault-blocking method to locate and confirm the fault, failing to fundamentally solve the problem of accurately blocking and pinpointing the faulty line. With the industry's increasing demands for power supply reliability and the formulation and promulgation of stricter standards, there is an urgent need in this field for a fault-blocking method and system to assist dispatching and management personnel in responding to single-phase grounding faults in substations.

[0005] Furthermore, on the one hand, there are differences in understanding among those skilled in the art; on the other hand, the applicant studied a large number of documents and patents when making this invention, but due to space limitations, not all details and contents were listed in detail. However, this does not mean that the present invention does not possess the features of these prior art. On the contrary, the present invention already possesses all the features of the prior art, and the applicant reserves the right to add relevant prior art to the background art. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention provides a method and system for auxiliary decision-making in single-phase ground fault substations using the disconnection method, particularly a method and system for auxiliary decision-making in single-phase ground fault substations with low-current grounding systems (hereinafter referred to as the disconnection auxiliary decision-making method and system). This allows local dispatching and operation management personnel to receive auxiliary decision-making information when a single-phase ground fault alarm is detected at a substation under their monitoring, necessitating a disconnection operation on the substation's feeder (distribution line). The system provides the following auxiliary decision-making information: if the single-phase ground fault occurs... On the feeder distribution lines of the substation, the probability of a single-phase grounding fault is calculated based on the overall probability of occurrence of each distribution line, providing a high or low probability indication of the fault. This allows for quick and accurate location of the faulty distribution line, enabling one or a few circuit breakers to quickly isolate the fault. Simultaneously, it avoids the short-term power outages and restorations of non-faulty distribution lines caused by repeated blind circuit breakers or conventional circuit breakers. If a single-phase grounding fault occurs on the busbar within the substation, it can be directly identified as a single-phase grounding fault on the busbar without any circuit breakers. This completely avoids power outages caused by circuit breakers for users of the substation distribution lines, allowing them to directly report substation busbar grounding faults.

[0007] This invention discloses a circuit-based auxiliary decision-making system for substations with single-phase grounding faults, comprising: a fault SMS notification receiving module, used to receive various fault information reported by various distribution terminals installed on the distribution lines, filter and extract the received "single-phase grounding fault SMS" information into first fault information, and then send the first fault information to the circuit-based auxiliary decision-making data cloud; a fault local analysis module, distributedly installed at the feeder distribution line bays and / or the low-voltage side bays of the main transformer in the substation, and when a single-phase grounding fault is detected below, sends the corresponding second fault information and / or third fault information at the installation location to the circuit-based auxiliary decision-making data cloud; and the circuit-based auxiliary decision-making data cloud. Furthermore, the road-assisted decision-making data cloud is configured as follows: the first fault information identified by the fault SMS notification receiving module is used to form a fault set of line number according to the Lx distribution line to obtain the fault set B of the off-site-Lx distribution line; the information result of the second fault information identified by the fault on-site judgment module is determined, and the information result and the fault set B of the off-site-Lx distribution line are used to perform probability calculation with different mathematical weights to calculate the comprehensive probability of single-phase grounding fault of Lx distribution line through the built-in fault occurrence probability calculation method.

[0008] This invention also discloses a circuit-based auxiliary decision-making system for single-phase ground fault substations. The configured circuit-based auxiliary decision-making data cloud can construct a fault set based on the Lx distribution line according to the first fault information to obtain the external-Lx distribution line fault set B; and can determine the information result of the second fault information. The information result and the external-Lx distribution line fault set B are used to perform probability calculations with different mathematical weights to calculate the comprehensive occurrence probability of single-phase ground faults in Lx distribution lines through the fault occurrence probability calculation method.

[0009] This invention also discloses a single-phase grounding fault substation pull-line method auxiliary decision-making system, which includes: a fault SMS notification receiving module, used to filter, extract and organize "single-phase grounding fault SMS" information into first fault information; a fault local analysis module, used to obtain the second fault information corresponding to the installation location when a single-phase grounding fault is detected below; and a pull-line auxiliary decision-making data cloud, which is configured to: receive the fault information sent by the fault SMS notification receiving module and the fault local analysis module, and perform probability calculations using different mathematical weights, so as to calculate the comprehensive occurrence probability of a single-phase grounding fault in the Lx distribution line through a built-in fault occurrence probability calculation method.

[0010] According to a preferred embodiment, the fault occurrence probability calculation method built into the road auxiliary decision data cloud calculates the fault probability of the external power distribution line by using the single-phase grounding fault information of the power distribution line sent by the external power distribution terminal. Combined with the judgment information generated by the fault on-site judgment module that monitors the distributed single-phase grounding fault at the head end of the internal power distribution line, the overall single-phase grounding fault occurrence probability of the entire Lx power distribution line is calculated.

[0011] According to a preferred embodiment, the road-laying auxiliary decision-making system further includes a road-laying auxiliary decision-making display module, which is used to dynamically display the results calculated by the road-laying auxiliary decision-making data cloud, thereby providing clear and explicit road-laying auxiliary decision-making information to the dispatching and management personnel.

[0012] This invention also discloses a circuit-assisted decision-making method for single-phase ground fault substations, which includes the following steps:

[0013] The first fault information is used to form a fault set by line number according to the Lx distribution line to obtain the fault set B of the off-site-Lx distribution line;

[0014] The information result of the second fault is determined, and the information result and the fault set B of the Lx distribution line outside the station are used to perform probability calculation with different mathematical weights, so as to calculate the comprehensive probability of single-phase grounding fault of Lx distribution line through the fault occurrence probability calculation method.

[0015] According to a preferred embodiment, the fault occurrence probability calculation method used in this invention is to calculate the fault probability of the external power distribution line by means of the single-phase grounding fault information of the power distribution line sent by the external power distribution terminal, and to combine the judgment information generated by the fault local judgment module for monitoring the distributed single-phase grounding fault at the head end of the internal power distribution line, and to comprehensively calculate the overall occurrence probability of the single-phase grounding fault of the entire power distribution line.

[0016] The beneficial technical effects of this invention include:

[0017] (1) This invention provides an independent circuit-blocking auxiliary decision-making system. It collects SMS messages proactively reported by the distribution automation system via a fault SMS notification receiving module and calculates the probability of single-phase grounding faults on external Lx distribution lines using circuit-blocking auxiliary decision-making data computing. Simultaneously, it combines information on single-phase grounding faults on internal Lx distribution lines and calculates the overall probability of single-phase grounding faults on the entire Lx distribution line using a comprehensive weighted method. This invention fully utilizes internal and external single-phase grounding fault information, providing more scientific decision support for dispatching and operation management personnel of municipal companies and providing a clear basis for circuit-blocking operations. Circuit-blocking operations are performed according to the ranking of the overall probability of single-phase grounding faults on each distribution line of the substation, improving the accuracy of circuit-blocking and enabling rapid disconnection of faulty lines with only one or a few circuit-blocking operations. Furthermore, for non-faulty distribution lines, it reduces unnecessary power outages and restoration operations, improving power supply reliability.

[0018] (2) The fault SMS notification receiving module proposed in this invention completely replaces the manual work of receiving and viewing SMS messages, avoids the uncertainty caused by manual analysis and identification of SMS information, and greatly shortens the scheduling fault handling time.

[0019] (3) The method for calculating the comprehensive occurrence probability of a single-phase grounding fault in a power distribution line provided by this invention has clear logic, low computational load, and strong fault tolerance. Even if there are false alarms or missed alarms at terminals on the power distribution line, it can still calculate a relatively accurate result (i.e., the probability of the faulty line is still very high). At the same time, by dynamically adjusting the weights, the accuracy of the comprehensive occurrence probability calculation result can be continuously optimized.

[0020] (4) This invention employs a road-assisted decision-making data cloud, which not only facilitates the integration of the calculation method for the comprehensive probability of single-phase grounding faults in distribution lines, but also provides a basic platform for the continuous upgrading and improvement of this calculation method. The data cloud can be deployed in a public cloud or a private cloud, laying the foundation for deploying a private cloud locally in the local city company to ensure the data security of the "road-assisted decision-making system" after its large-scale application in the power system in the future.

[0021] (5) The fault-based decision-making system of the present invention provides clear fault information when a single-phase ground fault occurs on the busbar by distributing fault-based judgment modules on the low-voltage side of the main transformer and at the head end of each feeder of the busbar. This completely solves the problem of fault failure that may be caused by conventional fault-based methods. Attached Figure Description

[0022] Figure 1 This is a hardware connection diagram of the road-pulling auxiliary decision-making system provided by the present invention;

[0023] Figure 2This is a schematic diagram of the working mode of the road-pulling auxiliary decision-making system provided by the present invention when a single-phase grounding fault occurs in the Lx distribution line of a substation;

[0024] Figure 3 This is a schematic diagram of the working mode of the road-pulling auxiliary decision-making system provided by the present invention when a single-phase ground fault occurs on the Mx bus of a substation;

[0025] Figure 4 This is a schematic diagram illustrating the definition of independent pathways under different circumstances provided by the present invention;

[0026] Figure 5 This is a schematic diagram of a single-phase grounding fault occurring below terminal 8 of the L1 power distribution line in a preferred embodiment of the present invention, where the terminal does not report a false alarm.

[0027] Figure 6 This is a schematic diagram of a single-phase grounding fault occurring below terminal 8 of L1 power distribution line and a false alarm occurring at the terminal in a preferred embodiment of the present invention.

[0028] Figure 7 This is a schematic diagram of a single-phase grounding fault occurring below terminal 8 of L1 power distribution line in a preferred embodiment of the present invention, where the terminal has false alarms and missed alarms.

[0029] Figure 8 This is a schematic diagram of a single-phase grounding fault occurring below terminal 8 of the L1 power distribution line in another preferred embodiment of the present invention, where the terminal has false alarms and missed alarms.

[0030] Figure 9 This is a schematic diagram of a situation where, in a preferred embodiment of the present invention, when the L1 power distribution line fails, the terminals in other power distribution lines receive false alarms.

[0031] Figure 10 This is a schematic diagram of a bus fault tripping auxiliary decision-making system provided by the present invention in a preferred embodiment;

[0032] Figure 11 This is a schematic diagram of a power distribution line fault tripping auxiliary decision-making system provided by the present invention in a preferred embodiment. Detailed Implementation

[0033] The following is a detailed explanation with reference to the accompanying drawings.

[0034] When the dispatch and operation management personnel of the municipal company discover a single-phase grounding fault in a substation and need to perform a single-phase grounding fault disconnection operation, they can follow the single-phase grounding fault information (i.e., the comprehensive occurrence probability information of single-phase grounding faults in Lx distribution lines within the substation or the single-phase grounding fault information of the busbar) provided by the disconnection auxiliary decision system of this invention to perform the disconnection operation of the distribution lines in descending order of the probability of the fault occurrence, so as to achieve rapid disconnection of the faulty line with only one or a few disconnection operations.

[0035] This invention discloses a single-phase ground fault substation pull-line method auxiliary decision-making system (hereinafter referred to as the pull-line auxiliary decision-making system), which may include the following sub-modules: a fault SMS notification receiving module, a fault on-site analysis module, a pull-line auxiliary decision-making data cloud, and a pull-line auxiliary decision-making display module. The deployment diagram of the above sub-modules is shown below. Figure 1 As shown.

[0036] Preferably, the fault SMS notification receiving module is used to receive various fault (SMS) information reported by various distribution terminals (such as pole-mounted circuit breakers FTU, fault indicators, etc.) that have been installed on the distribution lines of the designated substations by the "power supply company distribution automation system", and to filter, extract and organize the received "single-phase grounding fault SMS" information into the first fault information, and then send the first fault information to the road auxiliary decision data cloud. The first fault information can be "single-phase grounding fault at XX location on the Lx distribution line outside the station" information, where "XX location" refers to "a certain location" where the fault occurred.

[0037] Preferably, the fault SMS notification receiving module has powerful SMS parsing capabilities, enabling it to filter, extract, and organize various received fault (SMS) information. In particular, it should identify and convert "single-phase grounding fault SMS" information into primary fault information. It should also be able to organize this information according to a preset format for subsequent data analysis and processing. Preferably, the fault SMS notification receiving module can be equipped with a reliable wireless communication module, such as a 4G module, to ensure timely and accurate reception of fault SMS notifications from the power distribution automation system. Furthermore, considering the possibility of short-term communication interruptions, the fault SMS notification receiving module can also have a certain data storage capacity to ensure that data is not lost.

[0038] Preferably, the on-site fault assessment module can be distributed and installed at the feeder distribution line bays / low-voltage side bays of the main transformer in the substation. Once the on-site fault assessment module detects a single-phase grounding fault below it, it can send the corresponding second fault information and / or third fault information to the auxiliary decision-making data cloud. Preferably, the second fault information can be "single-phase grounding fault of Lx distribution line within the substation," and the third fault information can be "single-phase grounding fault of Mx busbar and below within the substation." Furthermore, the on-site fault assessment module can be directly deployed on the corresponding substation.

[0039] Preferably, the on-site fault diagnosis module has real-time monitoring and analysis capabilities, enabling it to monitor in real time whether a single-phase grounding fault has occurred below its installation location and generate corresponding second or third fault information. To improve the accuracy of single-phase grounding fault diagnosis and reduce false alarm and false negative rates, the module employs high-precision fault location technology. Preferably, the on-site fault diagnosis module should be installed at the feeder distribution line bay of the substation or at the low-voltage side bay of the main transformer. The equipment should possess good anti-interference capabilities and stability, and should also be equipped with necessary sensors and detection devices to accurately capture changes in electrical parameters, thereby accurately determining whether a single-phase grounding fault exists.

[0040] Preferably, the line-assisted decision-making data cloud can be used to receive the first fault information, the second fault information, and the third fault information sent by the fault SMS notification receiving module. Further, the line-assisted decision-making data cloud stores in advance the topological connections of various distribution terminals on each distribution line outside the designated substation, wherein this topological connection can be used to calculate the "comprehensive probability of single-phase grounding fault occurrence in Lx distribution line".

[0041] Preferably, the line-assisted decision-making data cloud not only includes algorithmic logic specifically for calculating the probability of single-phase grounding faults, but also encompasses a database management system. This system stores crucial data such as the topological connections of various distribution terminals on each distribution line outside the designated substation and their historical success rates, providing a solid data foundation for accurately calculating the overall probability of fault occurrence. Furthermore, the line-assisted decision-making data cloud also possesses a dynamic adjustment mechanism, capable of optimizing the PA and PB weight values ​​based on the total number and correct counts of historical judgments from the monitoring of the first-end distribution lines within the substation, thereby continuously improving the calculation results of the fault probability. Preferably, the line-assisted decision-making data cloud can be deployed using either a public cloud or a private cloud solution. The private cloud server can be directly housed in the power company's computer room, while the public cloud utilizes existing large-scale IoT data cloud resources, ensuring the system's flexibility and scalability. To guarantee the real-time performance and accuracy of data interaction, a stable network connection is required, and efficient data transmission must be achieved through 4G modules or other wireless communication technologies.

[0042] Preferably, the fault information received by the power supply line auxiliary decision-making data cloud can be used to calculate the probability of fault occurrence in the cloud according to specified rules, calculating the comprehensive probability of single-phase grounding fault in the Lx distribution line or the probability of single-phase grounding fault in the Mx busbar. The calculation results can be pushed to the power supply line auxiliary decision-making display module. Further, the specified rules can be the (single-phase grounding) fault occurrence probability calculation method provided by this invention. Preferably, the power supply line auxiliary decision-making data cloud can be deployed using a public cloud or a private cloud. The private cloud server can be directly deployed in the power supply company's computer room, while the public cloud server can utilize an existing large-scale IoT data cloud.

[0043] Preferably, the roadwork auxiliary decision display module can be used to dynamically display the results calculated from the roadwork auxiliary decision data cloud through various physical media (such as PCs, tablets, or mobile phone interfaces), thereby providing clear and concise roadwork auxiliary decision information to the dispatching and management personnel. Preferably, the roadwork auxiliary decision display module can be directly deployed in the dispatching room of the power supply company's dispatching and management personnel, typically on the desktop of the dispatching room.

[0044] Preferably, the fault SMS notification receiving module, the fault on-site analysis module, the road assist decision data cloud, and the road assist decision display module can all interact with each other via wireless communication. For example, a 4G module can be used to achieve data interaction.

[0045] Preferably, the road auxiliary decision-making data cloud can have built-in multiple specified rules for calculating the probability of fault occurrence. Regarding the comprehensive probability of a single-phase grounding fault in the Lx distribution line, the fault probability calculation method provided by this invention calculates the fault probability of the external distribution line using the single-phase grounding fault information transmitted from the external distribution terminal through corresponding rules. Combined with the judgment information generated by the fault on-site judgment module for monitoring distributed single-phase grounding faults at the head end of the internal distribution line, the comprehensive probability of a single-phase grounding fault in the entire distribution line is calculated.

[0046] The present invention also discloses a pull-line auxiliary decision-making method for single-phase ground fault substations (which can be referred to as the pull-line auxiliary decision-making method), which can calculate the probability of single-phase ground fault occurrence in distribution lines and can use the pull-line auxiliary decision-making system to provide accurate auxiliary decision-making information when a specific fault occurs.

[0047] Preferably, the road-assisted decision-making method of the present invention may include:

[0048] (1) The first fault information identified by the fault SMS notification receiving module is used to form a line number fault set according to the Lx power distribution line. The set name is "Single-phase grounding fault set B of the off-site-Lx power distribution line (hereinafter referred to as the off-site-Lx power distribution line fault set B)".

[0049] (2) For the second fault information identified by the fault local judgment module, determine its information result (the information result includes "fault" and "non-fault"). Then, use different mathematical weights to calculate the probability of the above information result and the fault set B of the Lx distribution line outside the station, so as to calculate the comprehensive probability of the single-phase grounding fault of the Lx distribution line through the built-in (single-phase grounding of the distribution line) fault occurrence probability calculation method.

[0050] Preferably, the method for calculating the probability of a single-phase grounding fault in a power distribution line according to the present invention can calculate the comprehensive probability A of a single-phase grounding fault in a power distribution line using the following formula: x :

[0051] A x =P A *A+P B *cal(B) (1)

[0052] P A +P B =100% (2),

[0053] In the above formula, P A To assign probability weights to the fault local assessment module, A takes a value of 1 (corresponding to the "fault" information result) or 0 (corresponding to the "non-fault" information result), P B P is the probability weight assigned to the fault SMS notification receiving module. A P B It can be allocated as needed, but it must satisfy the above formula (2), where cal(B) is the probability calculation for the "outside-Lx distribution line fault set B".

[0054] Preferably, A x The physical meaning is: data fusion of the fault assessment results at the beginning of the distribution lines within the substation and the fault assessment results of each distribution terminal installed on the distribution lines outside the substation. Furthermore, the local fault assessment modules installed on the distribution lines at the beginning of each feeder in the substation possess high accuracy in assessing single-phase grounding faults. x In the final calculation, it enables overall control of the entire power distribution line, achieving mutual verification of physical meaning. In practical applications, P can be dynamically adjusted as needed. A P B The weight values ​​are used to adjust performance based on different weights.

[0055] Preferably, the P described in this invention A P BThe weights assigned to the on-site fault assessment module and the fault SMS notification receiving module are, in effect, the weight allocation for in-station device assessment and off-site probability assessment. P can be determined using either a fixed allocation method or a dynamic allocation method. A P B The weight value.

[0056] Furthermore, when using a fixed allocation method, it can be done, for example, according to the site's internal weight P. A =50%, External weight P B =50% is fixed.

[0057] Furthermore, when using a dynamic allocation method, the above-mentioned fixed allocation method can be followed first (such as the site weight P). A =50%, External weight P B =50%) for initial system design, and then dynamically adjusted based on the historical success rate calculation results of the fault local judgment module monitored by the first-end distribution line in the station. The calculation formula is as follows:

[0058]

[0059] P A ≤P Amax (4),

[0060] In the above formula, N represents the total number of historical judgments made by the fault localization module monitoring the first-end distribution line within the station, m represents the total number of historical correct judgments made by the fault localization module monitoring the first-end distribution line within the station, k is a coefficient used to adjust the calculation results, which can be preset based on historical data, and P Amax For P A Setting an upper limit is used to prevent P A Excessive weighting leads to P B The weight is too small.

[0061] Based on the above formula, the on-site fault assessment module P can be dynamically adjusted according to the actual success rate of the actions. A The weights are assigned, and then 1-P A The value assigned to P B P is set according to the dynamic allocation method. A P B The probability calculation results of the entire road-assisted decision-making system can be continuously optimized.

[0062] Preferably, the probability of "the fault set B of the off-site-Lx distribution line" can be calculated using the following formula:

[0063]

[0064] In the above formula, N represents the number of independent paths in the "outside-Lx distribution line fault set B" that have reported single-phase grounding fault information terminals; m represents the total number of levels on a certain independent path; p j This represents the weights corresponding to different levels in an independent path. In an independent path, j represents the j-th level. The total number of terminals in an independent path from the first terminal to the last terminal reporting a single-phase ground fault in that path, as shown in the radial topology diagram, is the total number of levels. The first terminal in the independent path of the radial topology diagram is the first level, and so on, with the last terminal being the last level, for a total of m levels; a ji This represents the result (fault or non-fault) reported by the distribution terminal at level j on the i-th independent path. Among them, on the independent path, the terminal may miss the report (i.e., "non-fault").

[0065] Furthermore, the aforementioned "independent path" refers to the fact that, according to the principle of radial topology, in the topology diagram of the distribution lines fed out by each substation, the terminals on the same radial line belong to one independent path. The total number of independent paths in the "outside-Lx distribution line fault set B" is calculated in this way.

[0066] Figure 4 The diagram illustrates the definition of independent pathways under different conditions. Figure 4 Each terminal contains six distribution terminals. Solid circles indicate terminals that have issued single-phase ground fault information, while hollow circles indicate terminals that have not issued such information. Figure 4 In (a), there are N = 4 independent pathways, which are as follows: independent pathway ① consisting of terminal 1, terminal 4, and terminal 5, containing 3 levels; independent pathway ② consisting of terminal 1, terminal 4, and terminal 6, containing 3 levels; independent pathway ③ consisting of terminal 1 and terminal 2, containing 2 levels; and independent pathway ④ consisting of terminal 1 and terminal 3, containing 2 levels. Figure 4 In (b), there are N = 2 independent pathways, which are as follows: independent pathway ① consisting of terminal 1, terminal 4, and terminal 5, containing 3 levels; and independent pathway ④ consisting of terminal 1 and terminal 3, containing 2 levels. Figure 4 In (c), there are N=1 independent pathways, including independent pathway ② consisting of terminal 1, terminal 4, and terminal 6, which contains 3 levels. Figure 4 In (d), there are a total of N=1 independent paths, including independent path ③ consisting of terminal 1 and terminal 2, which contains 2 levels.

[0067] Preferably, the cal(B) of the present invention calculates the fault probability on each independent path separately, and then selects the path with the highest fault probability as the final fault probability result among multiple independent paths. Its physical meaning is: considering the influence of each terminal on each independent path on the final calculated fault probability, that is, the more fault-reporting terminals on each independent path, the larger the value. Simultaneously, the most effective (no false alarms, no missed alarms) independent path is obtained as the main factor for fault probability judgment. The calculation results on independent paths with false alarms are directly ignored after weighted calculation, thus exhibiting strong fault tolerance.

[0068] Therefore, the larger the calculated value of cal(B) for the entire external power distribution line, the greater the probability of a fault occurring in the entire power distribution line.

[0069] Preferably, p j You can first set the initial state (or initial weight coefficient) and then make dynamic adjustments.

[0070] Furthermore, in setting p j In the initial state, p can be j The average allocation means that all terminals at each level have the same fault diagnosis accuracy, where p j The initial weighting coefficients can be expressed mathematically as follows:

[0071]

[0072] In the above formula, m represents the total number of levels on a certain independent path.

[0073] Specifically, when m=1, p1=100%; when m=2, p1=p2=1 / 2=50%; when m=3, p1=p2=p3=1 / 3=33.3%; when m=4, p1=p2=p3=p4=1 / 4=25%, and so on.

[0074] Furthermore, after local dispatch and operation management personnel accurately select and disconnect the faulty power distribution line (i.e., disconnect it) based on the fault information, the maintenance personnel who go to the site for emergency repairs can actually verify the faulty section of the power distribution line, thereby statistically analyzing the correct alarms, false alarms, or missed alarms reported by each terminal. Therefore, the cumulative number of correct actions of each terminal can be counted according to a certain time period (such as monthly or after each fault), and then the statistical results can be dynamically imported into this system for dynamic updating of weighting coefficients.

[0075] Preferably, the overall correct action rate of each terminal can be calculated periodically based on the actual number of actions performed by each terminal afterward. The specific calculation method is as follows:

[0076] (1) When there is a grounding fault below the terminal, the correct alarm rate P fault_ok The calculation formula is as follows:

[0077]

[0078] In the above formula, N fault Indicates the number of failures below, m fault This indicates the number of times the terminal correctly triggered an alarm for a fault.

[0079] (2) When there is a grounding fault below the terminal, the false alarm rate P no_fault_ok The calculation formula is as follows:

[0080]

[0081] In the above formula, N no_fault Indicates the number of times no faults occurred below, m no_fault This indicates that the terminal does not send the number of faults.

[0082] (3) Calculate the average of the two parameters above and use it as the terminal's overall correct action rate P. check_ok The calculation formula is as follows:

[0083]

[0084] In the above formula, P check_ok It objectively reflects the accuracy of the terminal's actual actions.

[0085] This invention uses a dynamic adjustment method to increase the weight of terminals that have historically provided accurate alarms in the calculation of the next fault, while decreasing the weight of terminals that have historically provided false alarms or missed alarms in the calculation of the next fault, thereby continuously optimizing the probability calculation results.

[0086] Furthermore, assume there are m terminals on an independent path at level m, where the dynamically updated weight coefficient for the i-th terminal is P. check_ok The dynamic update weight coefficient P of terminal i (the i-th terminal) can be calculated using the following formula. i_updata :

[0087]

[0088] Therefore, the obtained dynamic update weight coefficient p can be used. j In the event of the next fault, the overall probability of a single-phase ground fault occurring in the Lx distribution line can be calculated more accurately.

[0089] Preferably, such as Figure 2 As shown, when a single-phase ground fault occurs in the Lx distribution line of the substation, the operation mode of the circuit breaker decision-making system is as follows:

[0090] (1) The local fault analysis module installed at the first end of the substation feeder detects a single-phase grounding fault on the Lx distribution line and sends the second fault information (i.e., "in-station-Lx distribution line single-phase grounding fault information") to the road auxiliary decision data cloud.

[0091] (2) The fault SMS notification receiving module receives SMS information at regular intervals, organizes it, and sends the first fault information reported by each line (i.e., "single-phase grounding fault at XX point of the Lx distribution line outside the station") to the road auxiliary decision data cloud.

[0092] (3) The road auxiliary decision data cloud will construct the fault set B of the off-site-Lx distribution line based on the first fault information, and calculate the comprehensive probability of single-phase grounding fault of Lx distribution line based on the fault set B of the off-site-Lx distribution line and the second fault information, and then send the result to the road auxiliary decision display module.

[0093] (4) The circuit-pulling auxiliary decision display module set on the user platform (such as tablet computer, PC or mobile phone) can dynamically display the distribution line number Lx and the corresponding single-phase grounding fault occurrence probability. The dispatch operation and management personnel can perform circuit-pulling operations as needed according to the distribution line number Lx and the corresponding single-phase grounding fault occurrence probability, from high to low probability, until the single-phase grounding fault disappears.

[0094] Preferably, such as Figure 3 As shown, when a single-phase ground fault occurs on the Mx busbar of the substation, the operation mode of the circuit auxiliary decision-making system is as follows:

[0095] (1) After the distributed installation fault local analysis module detects a single-phase grounding fault below the main transformer, it sends the third fault information (i.e., "single-phase grounding fault in the station-Mx bus and below") to the road auxiliary decision data cloud.

[0096] (2) If the fault SMS notification receiving module does not receive the first fault information sent by the feeder line of the substation (i.e., "single-phase grounding fault at XX point of the Lx distribution line outside the station"), it will not send the fault information.

[0097] (3) The road auxiliary decision data cloud can comprehensively judge that a single-phase grounding fault has occurred on the Mx bus of the substation based on the received third fault information and the situation where the first fault information is not received, and send the result to the road auxiliary decision display module;

[0098] (4) The circuit breaker decision display module set on the user platform can dynamically display the ground fault information of bus Mx, prompting the dispatching and operation management personnel to find the fault of bus Mx without performing circuit breaker operation.

[0099] Example 1

[0100] According to a preferred embodiment, such as Figure 5 As shown, a single-phase ground fault occurs below terminal 8 of distribution line L1. According to the transmitted data, it contains N=1 independent paths, consisting of terminals 1, 6, and 8. Calculate the overall probability A1 of the single-phase ground fault occurrence in distribution line L1 using typical example parameters:

[0101]

[0102] This embodiment demonstrates how to calculate the overall probability of a fault when all terminal reports are correct. In this embodiment, the overall probability of a single-phase grounding fault in the L1 distribution line is 100%.

[0103] Example 2

[0104] According to a preferred embodiment, such as Figure 6 As shown, a single-phase ground fault occurs below terminal 8 of distribution line L1. Terminal 5 reports a false alarm. According to the transmitted results, there are N=2 independent paths, namely: independent path 1 consisting of terminals 1, 6, and 8, and independent path 2 consisting of terminals 1, 2, 3, and 5. Calculate the overall probability A1 of the single-phase ground fault occurrence in distribution line L1 using typical example parameters:

[0105]

[0106] This embodiment demonstrates how to calculate the overall probability of a fault when the terminal reports a false alarm. In this embodiment, the overall probability of a single-phase ground fault in the L1 distribution line is 100%.

[0107] Example 3

[0108] According to a preferred embodiment, such as Figure 7 As shown, a single-phase ground fault occurs below terminal 8 of distribution line L1. Terminal 5 reports a false alarm, while terminal 6 fails to report one. According to the transmitted results, there are N=2 independent paths, namely: independent path 1 consisting of terminals 1, 6, and 8, and independent path 2 consisting of terminals 1, 2, 3, and 5. Calculate the overall probability A1 of the single-phase ground fault occurrence in distribution line L1 using typical example parameters:

[0109]

[0110] This embodiment demonstrates the calculation method for the overall probability of fault occurrence when the terminal has false alarms and missed alarms. In this embodiment, the overall probability of single-phase grounding fault occurrence in L1 distribution line is 83.3%.

[0111] Example 4

[0112] According to a preferred embodiment, such as Figure 8 As shown, a single-phase ground fault occurs below terminal 8 of distribution line L1. Terminal 5 reports a false alarm, while terminal 1 fails to report it. According to the transmitted results, there are N=2 independent paths, namely: independent path 1 consisting of terminals 1, 6, and 8, and independent path 2 consisting of terminals 1, 2, 3, and 5. Calculate the overall probability A1 of the single-phase ground fault occurrence in distribution line L1 using typical example parameters:

[0113]

[0114] This embodiment demonstrates the calculation method for the overall probability of fault occurrence when the terminal has false alarms and missed alarms. In this embodiment, the overall probability of single-phase grounding fault occurrence in L1 distribution line is 83.3%.

[0115] Example 5

[0116] According to a preferred embodiment, such as Figure 9 As shown, when a fault occurs in distribution line L1, terminal 5 will falsely report a fault in other distribution lines (such as Lx distribution line). According to the transmitted results, there are N=1 independent paths, consisting of terminals 1, 2, 3, and 5. Calculate the comprehensive probability A of a single-phase ground fault in distribution line Lx according to typical example parameters. X :

[0117]

[0118] This embodiment demonstrates the calculation method for the overall probability of fault occurrence when a non-faulty line Lx has a false alarm. In this embodiment, the calculated overall probability of fault occurrence for the non-faulty distribution line is relatively low.

[0119] Example 6

[0120] According to a preferred embodiment, such as Figure 7 As shown, a single-phase ground fault occurred below terminal 8 of power distribution line L1. Terminal 5 falsely reported the fault, while terminal 6 failed to report it. According to the transmitted results, there are N=2 independent paths, which are: independent path 1 consisting of terminal 1, terminal 6, and terminal 8, and independent path 2 consisting of terminal 1, terminal 2, terminal 3, and terminal 5.

[0121] Preferably, each terminal in the independent path is assigned a corresponding initial weight coefficient p according to the method of equally distributing weights. j To determine the initial state, specifically: for independent pathway 1, m=3, then p1=p2=p3=1 / 3=33.3%; for independent pathway 2, m=4, then p1=p2=p3=p4=1 / 4=25%.

[0122] Furthermore, the comprehensive probability A1 of a single-phase ground fault in the L1 distribution line is calculated based on the parameters of the above typical example:

[0123]

[0124] At this point, the overall probability of a single-phase ground fault occurring on the L1 distribution line is 83.33%.

[0125] Preferably, after fault statistics are compiled, the overall correct operation rate of each terminal is calculated periodically based on the actual number of subsequent operations of the actual power distribution terminals. For example, terminal 1: 90%, terminal 6: 50%, terminal 8: 80%, terminal 2: 90%, terminal 3: 90%, terminal 5: 60%.

[0126] Furthermore, for independent path 1 containing 3 terminals, the dynamic update weight coefficients for each terminal are calculated as follows:

[0127]

[0128] In the above formula, P 1_updata P is the dynamically updated weight coefficient for terminal 1. 2_updata For the dynamically updated weight coefficients of terminal 6, P 3_updata The weight coefficients for terminal 8 are dynamically updated.

[0129] Furthermore, for independent path 2 containing 4 terminals, the dynamic update weight coefficients for each terminal are calculated as follows:

[0130]

[0131] In the above formula, P 1_updata P is the dynamically updated weight coefficient for terminal 1. 2_updata For the dynamically updated weight coefficients of terminal 2, P 3_updata For the dynamically updated weight coefficients of terminal 3, P 4_updata The weight coefficients for terminal 5 are dynamically updated.

[0132] Preferably, the calculation results above show that for independent path 1, the weight of terminal 6 decreases; for independent path 2, the weight of terminal 5 decreases. Based on this, p can be adjusted. j Dynamic adjustments can be made, and adjustments can be made based on the adjusted p. j The overall probability of a single-phase ground fault occurring in the L1 power distribution line is recalculated, and the specific calculation method is as follows:

[0133]

[0134] Therefore, it can be seen that in this embodiment, by dynamically adjusting p jThe final calculated overall probability of a single-phase ground fault on the L1 distribution line (88.7%) is 5.4% higher than the initial calculated probability (83.3%). Therefore, in the next occurrence of a new fault, the probability can be increased by the new probability calculated using the new probability p. j It can more accurately calculate the probability of failure.

[0135] Example 7

[0136] According to a preferred embodiment, such as Figure 10 As shown, the local fault assessment module distributed on the low-voltage side of the main transformer reports a fault, while the local fault assessment modules distributed on the low-voltage side of each feeder in the substation do not report a fault. In this case, a ground fault is directly reported on the substation busbar. The circuit breaker auxiliary decision-making system of this invention can display the following on the circuit breaker auxiliary decision-making display module: Figure 10 The circuit breaker prompt interface shown provides bus grounding fault information to the local dispatch and operation management personnel of the municipal company, eliminating the need for circuit breaker installation.

[0137] Example 8

[0138] According to a preferred embodiment, if a line fault as described in Embodiment 3 occurs on distribution line L1, the overall probability of a single-phase ground fault on distribution line L1 is calculated to be 83.3%. Simultaneously, if a false alarm occurs at the off-site terminal on distribution line L2, the overall probability of a single-phase ground fault on distribution line L2 is calculated to be 12.5%. The road layout auxiliary decision-making system of this invention can display the following on the road layout auxiliary decision-making display module: Figure 11 The circuit breaker prompt interface shown provides the local dispatch and operation management personnel of the municipal company with decision-making information for circuit breaker of distribution line L1.

[0139] It should be noted that the specific embodiments described above are exemplary. Those skilled in the art can devise various solutions inspired by the disclosure of this invention, and these solutions all fall within the scope of this invention and its protection. Those skilled in the art should understand that this specification and its accompanying drawings are illustrative and do not constitute a limitation on the claims. The scope of protection of this invention is defined by the claims and their equivalents. This specification contains multiple inventive concepts; phrases such as "preferred" or "according to a preferred embodiment" indicate that the corresponding paragraph discloses an independent concept. The applicant reserves the right to file divisional applications based on each inventive concept. Throughout the text, the feature introduced by "preferred" is only an optional mode and should not be construed as mandatory. Therefore, the applicant reserves the right to abandon or delete relevant preferred features at any time.

Claims

1. A single-phase ground fault substation power flow method aided decision system, characterized in that, It comprises: Lalu auxiliary decision data cloud; Fault short message notification receiving module, for receiving various fault information reported by various power distribution terminals installed on power distribution lines, and filtering, extracting and arranging the received "single-phase ground fault short message" information among them as first fault information, and then sending the first fault information to the Lalu auxiliary decision data cloud; Fault on-site research and judgment module, distributedly installed at the interval of the feeder line of the substation and / or the low-voltage side of the main transformer, and when a single-phase ground fault occurs below, the corresponding second fault information and third fault information at the installation site are sent to the Lalu auxiliary decision data cloud, wherein, The Lalu auxiliary decision data cloud is configured to: The first fault information identified by the fault short message notification receiving module is arranged according to the line number fault set of the Lx power distribution line to obtain the station-out-Lx power distribution line fault set B; The information result of the second fault information identified by the fault on-site research and judgment module is determined, and the information result and the station-out-Lx power distribution line fault set B are calculated with different mathematical weights to calculate the comprehensive single-phase ground fault probability of the Lx power distribution line through the built-in fault occurrence probability calculation method.

2. The system of claim 1, wherein, The built-in fault occurrence probability calculation method of the Lalu auxiliary decision data cloud calculates the station-out power distribution line fault probability through the single-phase ground fault information of the station-out power distribution terminal, combines the research and judgment information generated by the fault on-site research and judgment module for monitoring the distributed single-phase ground fault at the head of the station-in power distribution line, and comprehensively calculates the comprehensive single-phase ground fault probability of the Lx power distribution line.

3. The system of claim 2, wherein, The LAR auxiliary decision-making data cloud can calculate the Lx power distribution line single-phase grounding fault comprehensive occurrence probability A by using the following formula x : ， In the above formula, P A is the probability weight assigned to the fault on-site judgment module, A takes the value of 1 or 0, P B is the probability weight assigned to the fault short message notification receiving module, and cal(B) is the probability calculation for "the set B of off-site-Lx distribution line faults".

4. The system of claim 3, wherein, The pull road auxiliary decision data cloud can determine P A , the weight value of P B , wherein, when the dynamic allocation mode is adopted, the pull road auxiliary decision data cloud can first perform system initial setting according to the fixed allocation mode, and then perform dynamic adjustment based on the historical action success rate calculation result of the fault on-site research and judgment module of the station head distribution line monitoring, and the calculation formula is as follows: ， In the above formula, N represents the total number of historical judgments of the fault on-site research and judgment module for monitoring the first-end distribution line in the station, m represents the total number of historical correct judgments of the fault on-site research and judgment module for monitoring the first-end distribution line in the station, k is a coefficient for adjusting the calculation result, and P Amax is the upper limit of the setting. A is the upper limit of the setting.

5. The system of claim 3, wherein, The Lalu auxiliary decision data cloud can calculate the "station-out-Lx power distribution line fault set B" by the following formula: ， In the above formula, N is the number of independent paths of the single-phase ground fault information terminal that has been reported in the "station-out-Lx power distribution line fault set B"; m represents the total number of levels in a certain independent path; p j represents the weight corresponding to different levels in an independent path, in an independent path, j represents the jth level in the independent path; a ji represents the result reported by the power distribution terminal at the jth level in the ith independent path.

6. The system of claim 5, wherein, The pull auxiliary decision data cloud can first set p j of the initial state, and then dynamically adjust it, wherein the pull auxiliary decision data cloud can set the initial weight coefficient of p j in an average distribution manner, and then regularly calculate the dynamic update weight coefficient of each terminal according to the actual correct action times of the actual power distribution terminal, and further realize the dynamic adjustment of p j .

7. The system of claim 1, wherein, It further comprises a Lalu auxiliary decision display module for dynamically displaying the results calculated by the Lalu auxiliary decision data cloud, thereby providing clear and explicit Lalu auxiliary decision information for the operation and management personnel of the ground station.

8. The system of claim 7, wherein, The Lalu auxiliary decision data cloud can comprehensively research and judge that the Mx bus of the substation has a single-phase ground fault based on the received third fault information and the condition that no first fault information is received, and send the result to the Lalu auxiliary decision display module to dynamically display the ground fault information of the bus Mx through the Lalu auxiliary decision display module, prompting the operation and management personnel of the ground station to find the fault of the bus Mx without performing the Lalu operation.

9. A single-phase ground fault substation pilot protection method assisted by the system of any one of claims 1-8, characterized in that, It comprises the following steps: The first fault information is arranged according to the line number fault set of the Lx power distribution line to obtain the station-out-Lx power distribution line fault set B; The information result of the second fault information is determined, and the information result and the station-out-Lx power distribution line fault set B are calculated with different mathematical weights to calculate the comprehensive single-phase ground fault probability of the Lx power distribution line through the fault occurrence probability calculation method.

10. The method of claim 9, wherein, The fault occurrence probability calculation method used is to calculate the fault probability of the off-station distribution line by the single-phase ground fault information of the off-station distribution line uploaded on the off-station distribution terminal, and to comprehensively calculate the single-phase ground fault comprehensive occurrence probability of the whole Lx distribution line in combination with the judgment information generated by the fault on-site judgment module for monitoring the first-end distributed single-phase ground fault of the in-station distribution line.

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