Auxiliary decision-making method and system for single-phase earth fault transformer substation switching-off method

Abstract

The invention relates to an auxiliary decision-making method and system for a single-phase earth fault transformer substation switching-off method. The system comprises a pull-out auxiliary decision-making data cloud; the fault short message notification receiving module is used for sending the first fault information to the pull-out auxiliary decision data cloud; and the fault in-situ studying and judging modules are installed at the intervals of the feeder line and the outgoing line of the transformer substation and / or the intervals of the low-voltage side of the main transformer in a distributed mode and send second fault information and / or third fault information corresponding to the installation position to the circuit pulling auxiliary decision data cloud when it is monitored that a single-phase earth fault occurs below the fault in-situ studying and judging modules. The method comprises the following steps: forming a line number fault set by first fault information according to an Lx distribution line to obtain an out-of-station Lx distribution line fault set B; and determining an information result of the second fault information, and carrying out probability calculation on the information result and the out-of-station Lx distribution line fault set B by adopting different mathematical weights so as to calculate the Lx distribution line single-phase earth fault comprehensive occurrence probability through a fault occurrence probability calculation method.

Description

Technical Field

[0001] The present invention relates to the technical field of single-phase grounding fault handling in distribution networks, and particularly to an auxiliary decision-making method and system for the substation switching-off method for single-phase grounding faults. Background Art

[0002] In many current city-level power supply companies' substations with voltages of 110 kV and below, when a single-phase grounding fault occurs in a distribution line (usually 6 - 35 kV, typically 10 kV) and fault removal is required, the dispatching department (local dispatching) of the city-level power supply company will use the switching-off method to find the fault based on the fault information reported by the substation dispatching telemetry, tele-signaling, and small-current grounding line selection devices. However, the small-current grounding line selection devices often have inaccurate line selection. The operation and management personnel of the local dispatching mainly rely on the switching-off method (the method of switching off one by one) to confirm the fault until the fault disappears. Therefore, there is often a long time for finding single-phase grounding faults. And switching off non-faulty lines will cause short-term power outages. Moreover, it is very likely that only because a single-phase grounding fault occurs in the busbar (such as busbar grounding caused by damaged lightning arresters), the switching-off method cannot eliminate the fault. At the same time, all the up-feed outgoing lines of the entire substation will experience the adverse effects of a short-term power outage and then power restoration, seriously reducing the power supply reliability of the distribution lines of the power supply company and bringing adverse effects to the user's power consumption experience, and being easily complained about.

[0003] CN102788933A discloses a method for finding small-current single-phase grounding faults in a power grid using an automatic switching-off controller. The specific steps of this invention are as follows: (1) Compile and import a switching-off sequence list; (2) Determine whether a small-current single-phase grounding fault has occurred; (3) When a small-current single-phase grounding fault occurs, the automatic switching-off controller performs a trial switching-off.

[0004] With the continuous increase in the coverage rate of various distribution terminals installed in the distribution automation system, after a single-phase grounding fault occurs on the distribution line, the operation and maintenance personnel of the power supply company will receive a single-phase grounding fault text message sent by the distribution automation system on their mobile phones. When the substation needs to perform a fault switching-off operation, the operation and management personnel of the local dispatching can, through telephone communication with the operation and maintenance personnel and based on the fault information reported by users, combined with the conventional telemetry and tele-signaling data of the substation, perform the fault switching-off operation. However, there are still uncertain factors such as messy, missing, or delayed reported text message information, resulting in the operation and management personnel of the local dispatching still needing to make comprehensive information judgments based on past experience. Often, they still finally find and confirm the fault according to the inherent switching-off method, and do not fundamentally solve the problem of accurately switching off and determining the faulty line. With the continuous improvement of the industry's requirements for power supply reliability and the formulation and promulgation of relatively stricter standards, there is an urgent need in this field for an auxiliary decision-making method and system for the substation switching-off method for single-phase grounding faults to more effectively assist the operation and management personnel of the local dispatching in dealing with single-phase grounding faults.

[0005] In addition, on the one hand, there are differences in the understanding of those skilled in the art; on the other hand, when the applicant made this invention, a large number of documents and patents were studied, 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 arts. On the contrary, the present invention already possesses all the features of the prior arts, and the applicant reserves the right to add relevant prior arts in the background art. Summary of the Invention

[0006] Aiming at the deficiencies of the prior art, the present invention provides a single-phase grounding fault substation switching-off method and system for auxiliary decision-making, in particular, a single-phase grounding fault substation switching-off method and system for auxiliary decision-making for a small current grounding system (hereinafter referred to as the switching-off auxiliary decision-making method and the switching-off auxiliary decision-making system). When the local dispatching operation and management personnel find that a single-phase grounding fault alarm message occurs in a certain substation monitored by the dispatching and need to perform the switching-off operation for the single-phase grounding fault of the substation feeder (distribution line), the switching-off auxiliary decision-making system can provide the following auxiliary decision-making information: If the single-phase grounding fault occurs on the substation feeder distribution line, according to the calculated comprehensive occurrence probability of the single-phase grounding fault of each distribution line, a prompt for the high or low fault probability is provided to quickly and accurately locate the faulty distribution line, perform one or a small number of switching-off operations, complete the rapid removal of the fault, and at the same time avoid the short-time power outage and restoration phenomenon of non-faulty distribution lines caused by multiple conventional blind switching-off or switching-off in the inherent mode; If the single-phase grounding fault occurs on the busbar in the substation, it can directly judge that a single-phase grounding fault has occurred on the busbar, without any switching-off operation, completely avoiding the power supply interruption of the substation distribution line users due to switching-off for trial, and directly reporting the single-phase grounding fault of the substation busbar for repair.

[0007] The present invention discloses an auxiliary decision-making system for the switching-off method of a single-phase grounding fault substation, which includes: a fault SMS notification receiving module, configured to receive various fault information reported by various distribution terminals installed on the distribution line, filter, extract and organize the received "single-phase grounding fault SMS" information into first fault information, and then send the first fault information to the switching-off auxiliary decision-making data cloud; a fault local judgment module, distributed at the distribution line interval of the substation outgoing line and / or the low-voltage side interval of the main transformer, and when a single-phase grounding fault occurs below, send the corresponding second fault information and / or third fault information at the installation location to the switching-off auxiliary decision-making data cloud; a switching-off auxiliary decision-making data cloud. Further, the switching-off auxiliary decision-making data cloud is configured to: form a line number fault set of the first fault information recognized by the fault SMS notification receiving module according to the Lx distribution line to obtain an off-site - Lx distribution line fault set B; determine the information result of the second fault information recognized by the fault local judgment module, and perform probability calculation on the information result and the off-site - Lx distribution line fault set B using different mathematical weights, so as to calculate the comprehensive occurrence probability of the single-phase grounding fault of the Lx distribution line through the built-in fault occurrence probability calculation method.

[0008] The present invention also discloses an auxiliary decision-making system for the switching-off method of a single-phase grounding fault substation, and the configured switching-off auxiliary decision-making data cloud can form a line number fault set of the first fault information according to the Lx distribution line to obtain an off-site - Lx distribution line fault set B; and can determine the information result of the second fault information, and perform probability calculation on the information result and the off-site - Lx distribution line fault set B using different mathematical weights, so as to calculate the comprehensive occurrence probability of the single-phase grounding fault of the Lx distribution line through the fault occurrence probability calculation method.

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

[0010] According to a preferred embodiment, the fault occurrence probability calculation method built in the switching-off auxiliary decision-making data cloud calculates the fault probability of the off-station distribution line through the single-phase grounding fault information of the distribution line sent by the off-station distribution terminal, and combines the judgment information generated by the fault local judgment module for monitoring the distributed single-phase grounding fault at the head end of the in-station distribution line, and comprehensively calculates the comprehensive occurrence probability of the single-phase grounding fault of the entire Lx distribution line.

[0011] According to a preferred embodiment, the switching-off auxiliary decision-making system further includes a switching-off auxiliary decision-making display module, which is used to dynamically display the results calculated by the switching-off auxiliary decision-making data cloud, so as to provide clear and definite switching-off auxiliary decision-making information for the operation and management personnel of the local dispatching center.

[0012] The present invention also discloses a method for assisting decision-making in the switching-off of a substation with single-phase grounding faults, which includes the following steps:

[0013] Group the first fault information into a fault set according to the line numbers of the Lx distribution line to obtain the off-station - Lx distribution line fault set B;

[0014] Determine the information result of the second fault information, and calculate the probability of the second fault information and the off-station - Lx distribution line fault set B using different mathematical weights, so as to calculate the comprehensive occurrence probability of the single-phase grounding fault of the Lx distribution line through the fault occurrence probability calculation method.

[0015] According to a preferred embodiment, the fault occurrence probability calculation method used in the present invention calculates the fault probability of the off-station distribution line through the single-phase grounding fault information of the distribution line sent by the off-station distribution terminal, and combines the judgment information generated by the fault local judgment module for monitoring the distributed single-phase grounding fault at the head end of the in-station distribution line, and comprehensively calculates the comprehensive occurrence probability of the single-phase grounding fault of the entire distribution line.

[0016] The beneficial technical effects of the present invention include:

[0017] (1) The present invention provides an independent power cut-off auxiliary decision-making system. The system collects the SMS information actively reported by the distribution automation system through the fault SMS notification receiving module, and calculates the occurrence probability of single-phase grounding faults on the off-station Lx distribution line through the power cut-off auxiliary decision-making data cloud computing. At the same time, combining the information of single-phase grounding faults on the in-station Lx distribution line, the comprehensive occurrence probability of single-phase grounding faults on the entire Lx distribution line is calculated by using the comprehensive weighting method. The present invention makes full use of the single-phase grounding fault information inside and outside the substation, provides more scientific decision-making support for the dispatching operation management personnel of the city company, and provides a clear basis for the power cut-off operation. The power cut-off operation is carried out according to the sorting of the comprehensive occurrence probabilities of single-phase grounding faults on each distribution line of the substation, which improves the accuracy of the power cut-off and realizes the rapid removal of the faulty line with one or a small number of power cut-off operations. In addition, for non-faulty distribution lines, unnecessary power outage and power restoration operations are reduced, and the power supply reliability is improved.

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

[0019] (3) The calculation method of the comprehensive occurrence probability of (single-phase grounding of distribution lines) faults provided by the present invention has clear logic, small calculation amount, and strong fault tolerance ability. Even if there are false alarms or missed reports at the terminals on the distribution line, it can still calculate relatively accurate results (that is, the probability of the faulty line is still very high). At the same time, through the calculation method of dynamically adjusting the weight, the accuracy of the calculation result of the comprehensive occurrence probability of faults can be continuously optimized.

[0020] (4) The present invention adopts the power cut-off auxiliary decision-making data cloud, which can not only conveniently integrate the calculation method of the comprehensive occurrence probability of single-phase grounding faults on the distribution line, but also provides a basic platform for continuously upgrading and improving this calculation method in the future. The data cloud can be deployed as a public cloud or a private cloud, laying a foundation for deploying a private cloud locally in the city company to ensure the data security of the "power cut-off auxiliary decision-making system" after large-scale promotion and application in the power system in the future.

[0021] (5) The power cut-off auxiliary decision-making system of the present invention distributes and deploys the fault local judgment module at the low-voltage side of the main transformer and the head ends of each feeder on the bus, so that when a single-phase grounding fault occurs on the bus, clear fault information can be provided, thus completely solving the problem of power cut-off failure that may be caused by the conventional power cut-off method. Description of the Drawings

[0022] Figure 1 is a schematic diagram of the hardware connection of the power cut-off auxiliary decision-making system provided by the present invention;

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

[0024] Figure 3 It is a schematic diagram of the operation mode of the switching-off auxiliary decision-making system provided by the present invention when a single-phase grounding fault occurs on the Mx busbar of the substation;

[0025] Figure 4 It is a schematic diagram of the definition of independent paths under different conditions provided by the present invention;

[0026] Figure 5 It is a schematic diagram of the situation where a single-phase grounding fault occurs below the terminal 8 of the L1 distribution line and there is no false alarm at the terminal in a preferred embodiment provided by the present invention;

[0027] Figure 6 It is a schematic diagram of the situation where a single-phase grounding fault occurs below the terminal 8 of the L1 distribution line and there is a false alarm at the terminal in a preferred embodiment provided by the present invention;

[0028] Figure 7 It is a schematic diagram of the situation where a single-phase grounding fault occurs below the terminal 8 of the L1 distribution line and there are false alarms and missed alarms at the terminal in a preferred embodiment provided by the present invention;

[0029] Figure 8 It is a schematic diagram of the situation where a single-phase grounding fault occurs below the terminal 8 of the L1 distribution line and there are false alarms and missed alarms at the terminal in another preferred embodiment provided by the present invention;

[0030] Figure 9 It is a schematic diagram of the situation where there is a false alarm at the terminal in other distribution lines when the L1 distribution line fails in a preferred embodiment provided by the present invention;

[0031] Figure 10 It is a schematic diagram of the display of the switching-off auxiliary decision-making system when a busbar fault occurs in a preferred embodiment provided by the present invention;

[0032] Figure 11 It is a schematic diagram of the display of the switching-off auxiliary decision-making system when a distribution line fails in a preferred embodiment provided by the present invention. Detailed implementation manners

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

[0034] When the operation management personnel of the local dispatching of the prefecture-level power company need to perform the single-phase grounding fault disconnection operation to cut off the fault after discovering a single-phase grounding fault in the substation, they can follow the single-phase grounding fault information provided by the disconnection auxiliary decision-making system of the present invention (i.e., the comprehensive occurrence probability information of the single-phase grounding fault of the Lx distribution line in the substation or the single-phase grounding fault information of the bus), and perform the disconnection operation of the distribution line in sequence according to the probability of the distribution line fault occurrence from high to low, so as to complete the rapid cutting off of the fault line with 1 or a small number of disconnection operations.

[0035] A single-phase grounding fault substation disconnection method auxiliary decision-making system (which can be abbreviated as the disconnection auxiliary decision-making system) disclosed by the present invention may include the following sub-modules: a fault SMS notification receiving module, a fault local judgment module, a disconnection auxiliary decision-making data cloud, and a disconnection auxiliary decision-making display module. The deployment schematic diagram of the above sub-modules is as Figure 1 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.) installed on the distribution line of the designated substation by the "power supply company distribution automation system", and filter, extract and sort out the "single-phase grounding fault SMS" information received therein into the first fault information, and then send the first fault information to the disconnection auxiliary decision-making data cloud. Among them, the first fault information may be the information of "single-phase grounding fault at XX place on the out-of-station Lx distribution line", and the above "XX place" refers to the "somewhere" where the fault occurs.

[0037] Preferably, the fault SMS notification receiving module has a powerful SMS parsing function, which can filter, extract and sort out various fault (SMS) information received, especially identify and convert the "single-phase grounding fault SMS" information into the first fault information, and at the same time, it also needs to have the ability to sort out these information in 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 that the fault SMS notification from the distribution automation system can be received in a timely and accurate manner. In addition, considering the possible short-term communication interruption situation, the fault SMS notification receiving module can also have a certain data storage capacity to ensure that the data will not be lost.

[0038] Preferably, the on-site fault judgment module can be distributedly installed at the distribution line interval of the substation feeder or at the low-voltage side interval of the main transformer. Once the on-site fault judgment module detects a single-phase grounding fault occurring below, it can send the corresponding second fault information and / or third fault information of the installation location to the switching assistance decision-making data cloud. Preferably, the second fault information can be the information of "single-phase grounding fault on the Lx distribution line in the substation", and the third fault information can be the information of "single-phase grounding fault on the Mx busbar and below in the substation". Further, the on-site fault judgment module can be directly deployed on the corresponding substation.

[0039] Preferably, the on-site fault judgment module has the ability of real-time monitoring and analysis, can monitor in real time whether a single-phase grounding fault has occurred below the installation position, and generate the corresponding second fault information or third fault information. In order to improve the judgment accuracy of single-phase grounding faults, reduce the false alarm rate and missed alarm rate, this module adopts high-precision fault location technology. Preferably, the on-site fault judgment module should be installed at the distribution line interval of the substation feeder or at the low-voltage side interval of the main transformer, and the equipment is required to have good anti-interference ability and stability. At the same time, necessary sensors and detection devices also need to be configured to accurately capture the changes of electrical parameters, so as to accurately judge whether there is a single-phase grounding fault.

[0040] Preferably, the switching assistance decision-making data cloud can be used to receive the first fault information, second fault information and third fault information sent by the fault SMS notification receiving module. Further, in the switching assistance decision-making data cloud, the topological up and down connection relationships of various distribution terminals on each distribution line outside the specified substation are stored in advance, and the topological relationship can be applied to the calculation of the "comprehensive occurrence probability of single-phase grounding fault on the Lx distribution line".

[0041] Preferably, the switching assistance decision-making data cloud not only includes the algorithm logic specifically used to calculate the occurrence probability of single-phase grounding faults, but also covers a database management system. This system stores important data such as the topological up and down connection relationships of various distribution terminals on each distribution line outside the specified substation and the historical action success rate, providing a solid data basis for accurately calculating the comprehensive occurrence probability of faults. In addition, the switching assistance decision-making data cloud also has a dynamic adjustment mechanism, which can optimize the PA and PB weight values based on the total number of historical judgment times and the correct times monitored at the head of the distribution line in the substation, so as to continuously improve the calculation result of the fault occurrence probability. Preferably, the switching assistance decision-making data cloud can adopt either a public cloud deployment method or a private cloud deployment plan. Among them, the private cloud server can be directly placed in the power supply company's computer room, while the public cloud uses the existing large-scale Internet of Things data cloud resources, ensuring the flexibility and scalability of the system. In order to ensure the real-time and accurate data interaction, a stable network connection needs to be configured, and high-efficiency data transmission is realized through a 4G module or other wireless communication technologies.

[0042] Preferably, the fault information received by the switching-off auxiliary decision data cloud can calculate the probability of fault occurrence according to specified rules in the cloud, calculate the comprehensive probability of single-phase grounding fault of the Lx distribution line or the single-phase grounding fault of the Mx bus, and the calculation result can be pushed to the switching-off auxiliary decision display module. Further, the above-mentioned specified rules can be the fault occurrence probability calculation method provided by the present invention (for single-phase grounding fault of distribution lines). Preferably, the switching-off auxiliary decision data cloud can be deployed using a public cloud or a private cloud. Among them, the private cloud server can be directly deployed in the power supply company's computer room, and the public cloud server can use the existing large-scale Internet of Things data cloud.

[0043] Preferably, the switching-off auxiliary decision display module can be used to dynamically display the results calculated by the switching-off auxiliary decision data cloud through various physical media (such as a PC, a tablet computer, or a mobile phone interface, etc.), so as to provide clear and definite switching-off auxiliary decision information for the operation and management personnel of the local dispatching. Preferably, the switching-off auxiliary decision display module can be directly deployed in the dispatching room of the operation and management personnel of the local dispatching of the power supply company, and is typically deployed on the desktop of the dispatching room.

[0044] Preferably, wireless communication methods can be used for data interaction between the above-mentioned fault SMS notification receiving module, the on-site fault judgment module, the switching-off auxiliary decision data cloud, and the switching-off auxiliary decision display module. For example, a 4G module can be used to achieve data interaction.

[0045] Preferably, there can be various specified rules for calculating the probability of fault occurrence built into the switching-off auxiliary decision data cloud. For the comprehensive probability of single-phase grounding fault of the Lx distribution line, the fault occurrence probability calculation method provided by the present invention (for single-phase grounding fault of distribution lines) calculates the fault probability of the off-station distribution line through the single-phase grounding fault information of the distribution line sent by the off-station distribution terminal according to the corresponding rules, and combines the judgment information generated by the on-site fault judgment module for monitoring the single-phase grounding fault at the head end of the in-station distribution line to comprehensively calculate the comprehensive probability of single-phase grounding fault of the entire distribution line.

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

[0047] Preferably, the switching-off auxiliary decision-making method of the present invention may include:

[0048] (1) The first fault information identified by the fault SMS notification receiving module is formed into a line number fault set according to the Lx distribution line, and its set name is "off-station - Lx distribution line single-phase grounding fault set B (hereinafter can be simply referred to as off-station - Lx distribution line fault set B);

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

[0050] Preferably, the (single-phase grounding fault of the distribution line) fault occurrence probability calculation method of the present invention can calculate the comprehensive occurrence probability A of the single-phase grounding fault of the Lx distribution line through 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 is the probability weight assigned to the on-site fault judgment module, A takes a value of 1 (corresponding to the information result of "fault") or 0 (corresponding to the information result of "non-fault"), P B is the probability weight assigned to the fault SMS notification receiving module, P A , P B can be allocated as needed, but it needs to satisfy the above formula (2), and cal(B) is the probability calculation for the "off-site - Lx distribution line fault set B".

[0054] Preferably, the physical meaning of A x is: the data fusion of the fault judgment result at the head end of the in-station distribution line and the fault judgment results of each distribution terminal installed on the off-site distribution line. Moreover, the on-site fault judgment modules installed at the head ends of each feeder line in the substation itself have high accurate performance in judging single-phase grounding faults. In the final calculation of A x , it can achieve overall control of the entire distribution line and the physical meaning of mutual verification. In actual application, the weight values of P A , P B can be dynamically adjusted as needed to achieve performance adjustment based on different weights.

[0055] Preferably, the P A , P BThey are the weights assigned to the on-site fault judgment module and the fault SMS notification receiving module respectively. In fact, they are the weight distributions of in-station device judgment and off-station probability judgment. Among them, a fixed distribution method or a dynamic distribution method can be used to determine P A , P B .

[0056] Furthermore, when the fixed distribution method is adopted, for example, the in-station weight P A = 50%, and the off-station weight P B = 50% can be set fixedly.

[0057] Furthermore, when the dynamic distribution method is adopted, first, the system can be initially set according to the above fixed distribution method (such as the in-station weight P A = 50%, and the off-station weight P B = 50%). Then, based on the calculation result of the historical action success rate of the on-site fault judgment module for monitoring the in-station first-end distribution line, dynamic adjustment is carried out. Among them, 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 of the on-site fault judgment module for monitoring the in-station first-end distribution line, m represents the total number of correct historical judgments of the on-site fault judgment module for monitoring the in-station first-end distribution line, k is a coefficient used to adjust the calculation result, which can be preset according to historical data, and P Amax is the upper limit of the setting of P A , which is used to prevent the weight of P A from being too large and resulting in the weight of P B being too small.

[0061] According to the above calculation, the weight distribution of the in-station on-site fault judgment module P A can be dynamically adjusted according to the actual action success rate, and then the value of 1 - P A is assigned to P B . Setting P A , P B according to the dynamic distribution method can continuously optimize the probability calculation result of the entire line-switching auxiliary decision-making system.

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

[0063]

[0064] In the above formula, N is the number of independent paths of the terminals that have reported single-phase grounding fault information existing in the "off-site - Lx distribution line fault set B"; m represents the total number of levels on a certain independent path; p j represents the weight corresponding to different levels in the independent path. On an independent path, j represents the j-th level on the independent path. From the first terminal to the last terminal that reports single-phase grounding fault information in the independent path on the radial topology diagram, the total number of terminals included is the total number of levels. The first one in the independent path on the radial topology diagram is the first level, and so on. The last one is the last level, with a total of m levels; a ji represents the result (fault or non-fault) reported by the distribution terminal at the j-th level on the i-th independent path. Among them, on the independent path, the terminal may have missed reports (i.e., "non-fault").

[0065] Furthermore, the above "independent path" refers to: in the topology diagram of each distribution line fed out by the substation, according to the radial topology principle, the terminals on the same ray are considered to belong to 1 independent path. Calculate the total number of independent paths existing in the "off-site - Lx distribution line fault set B" in this way.

[0066] Figure 4 shows schematic diagrams of the definition of independent paths in different cases, Figure 4 each of which contains 6 distribution terminals. Among them, the solid circles represent the terminals that send single-phase grounding fault information, and the hollow circles represent the terminals that do not send single-phase grounding fault information. In Figure 4 (a), there are a total of N = 4 independent path numbers, which are: independent path ① composed of terminal 1, terminal 4, and terminal 5, which contains 3 levels; independent path ② composed of terminal 1, terminal 4, and terminal 6, which contains 3 levels; independent path ③ composed of terminal 1 and terminal 2, which contains 2 levels; independent path ④ composed of terminal 1 and terminal 3, which contains 2 levels. In Figure 4 (b), there are a total of N = 2 independent path numbers, which are: independent path ① composed of terminal 1, terminal 4, and terminal 5, containing 3 levels; independent path ④ composed of terminal 1 and terminal 3, which contains 2 levels. In Figure 4 (c), there is a total of N = 1 independent path number, independent path ② composed of terminal 1, terminal 4, and terminal 6, containing 3 levels. In Figure 4 (d), there is a total of N = 1 independent path number, independent path ③ composed of terminal 1 and terminal 2, containing 2 levels.

[0067] Preferably, for cal(B) of the present invention, the failure probability of each independent path is calculated separately, and then among multiple independent paths, the maximum failure probability is selected as the final failure probability result. Its physical meaning is as follows: Considering the influence of each terminal on each independent path on the finally calculated failure occurrence probability, that is, the more the number of reported faulty terminals on each independent path, the larger the value. At the same time, the actual most effective (without false alarms and missed alarms) independent path is obtained as the main factor for judging the failure probability. For the calculation results on the independent paths caused by false alarms, they will be directly ignored after being calculated based on weights. Therefore, it has strong fault tolerance.

[0068] Based on this, the larger the value of cal(B) calculated for the entire off-station power distribution line finally, the greater the probability of failure of the entire power distribution line.

[0069] Preferably, p j The initial state (or called the initial weight coefficient) can be set first, and then dynamic adjustment is carried out.

[0070] Furthermore, when setting the initial state of p j , p j can be evenly distributed. Its physical meaning can be considered that the terminals at each level have the same accurate performance in failure judgment. Among them, the initial weight coefficient of p j can be expressed by the following mathematical formula:

[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 the local dispatching operation and management personnel accurately select and disconnect the faulty power distribution line (i.e., pull the switch) according to the fault information, the maintenance personnel going to the site for emergency repair can actually verify the fault section of the final power distribution line, so as to count the situations of correct alarms, false alarms, or missed alarms of each terminal reported. Therefore, the cumulative correct action times of each terminal can be counted according to a certain time period (such as monthly or after each fault), and then the statistical result is dynamically imported into this system for dynamic update of the weight coefficient.

[0075] Preferably, according to the actual action times of each terminal after the event regularly, the comprehensive correct action rate of each terminal can be calculated. The specific calculation method is as follows:

[0076] (1) When a ground fault occurs below the terminal, the correct alarm rate P fault_ok is calculated as follows:

[0077]

[0078] In the above formula, N fault represents the number of faults occurring below, and m fault represents the number of correct alarm faults of the terminal.

[0079] (2) When there is no ground fault below the terminal, the non-false alarm rate P no_fault_ok is calculated as follows:

[0080]

[0081] In the above formula, N no_fault represents the number of times no fault occurs below, and m no_fault represents the number of times the terminal does not send a fault.

[0082] (3) Calculate the average value of the above two parameters and use it as the comprehensive correct action rate P check_ok of the terminal, and its calculation formula is as follows:

[0083]

[0084] In the above formula, P check_ok objectively expresses the actual action accuracy of the terminal.

[0085] Through this dynamic adjustment method, the present invention increases the corresponding weight of the terminal with accurate historical alarms in the next fault calculation, and reduces the corresponding weight of the terminal with historical false alarms and missed alarms in the next fault calculation, so as to continuously optimize the probability calculation result.

[0086] Furthermore, assume that there are m terminals on the independent path of the mth level, and the dynamic update weight coefficient corresponding to the ith terminal among them is P check_ok i. The dynamic update weight coefficient P i_updata of this terminal (the ith terminal) can be calculated through the following formula:

[0087]

[0088] Therefore, the obtained dynamic update weight coefficient p j can be used to more accurately calculate the comprehensive occurrence probability of single-phase grounding faults on the Lx distribution line during the next fault.

[0089] Preferably, as Figure 2 shown, when a single-phase grounding fault occurs on the Lx distribution line of the substation, the working mode of the switching-off auxiliary decision-making system is as follows:

[0090] (1) The fault local judgment module installed distributively at the head end of the substation feeder line detects a single-phase grounding fault on the Lx distribution line and sends the second fault information (i.e., the information of "single-phase grounding fault on the Lx distribution line in the substation") to the switching-off auxiliary decision-making data cloud;

[0091] (2) The fault SMS notification receiving module regularly receives SMS information, and after sorting, sends the first fault information reported by each line (i.e., the information of "single-phase grounding fault at XX place on the Lx distribution line outside the substation") to the switching-off auxiliary decision-making data cloud;

[0092] (3) The switching-off auxiliary decision-making data cloud forms the fault set B of the Lx distribution line outside the substation with the first fault information, calculates the comprehensive occurrence probability of the single-phase grounding fault on the Lx distribution line based on the fault set B of the Lx distribution line outside the substation and the second fault information, and then sends the result to the switching-off auxiliary decision-making display module;

[0093] (4) The switching-off auxiliary decision-making display module set on the user platform (such as a tablet computer, a PC or a mobile phone, etc.) can dynamically display the distribution line number Lx where the single-phase grounding fault occurs and the corresponding single-phase grounding fault occurrence probability. The dispatching operation management personnel at the local dispatching can, according to the distribution line number Lx and the corresponding single-phase grounding fault occurrence probability, perform the switching-off operation in sequence as needed from high to low until the single-phase grounding fault disappears.

[0094] Preferably, as Figure 3 shown, when a single-phase grounding fault occurs on the Mx busbar of the substation, the working mode of the switching-off auxiliary decision-making system is as follows:

[0095] (1) After the fault local judgment module installed distributively detects a single-phase grounding fault under the main transformer, it sends the third fault information (i.e., the information of "single-phase grounding fault on the Mx busbar and below in the substation") to the switching-off auxiliary decision-making data cloud;

[0096] (2) If the fault SMS notification receiving module does not receive the first fault information (i.e., the information of "single-phase grounding fault at XX place on the Lx distribution line outside the substation") sent from the feeder line of the substation it belongs to, it does not send the fault information;

[0097] (3) The switching-off auxiliary decision-making data cloud can comprehensively judge that a single-phase grounding fault occurs on the Mx busbar of the substation based on the received third fault information and the situation of not receiving the first fault information, and send the result to the switching-off auxiliary decision-making display module;

[0098] (4) The switching-off auxiliary decision-making display module set on the user platform can dynamically display the grounding fault information of the busbar Mx, prompting the dispatching operation management personnel at the local dispatching to search for the fault of the busbar Mx, and there is no need to perform the switching-off operation.

[0099] Example 1

[0100] According to a preferred embodiment, as Figure 5 shown, a single-phase ground fault occurs below the terminal 8 of the distribution line L1. According to the uplink result, there is N = 1 independent path, which is composed of terminal 1, terminal 6, and terminal 8. Calculate the comprehensive occurrence probability A1 of the single-phase ground fault of the L1 distribution line according to the typical example parameters:

[0101]

[0102] This embodiment shows the calculation method of the comprehensive occurrence probability of the fault when all terminals report correctly. In this embodiment, the comprehensive occurrence probability of the single-phase ground fault of the L1 distribution line is 100%.

[0103] Example 2

[0104] According to a preferred embodiment, as Figure 6 shown, a single-phase ground fault occurs below the terminal 8 of the distribution line L1, and terminal 5 gives a false alarm. According to the uplink result, there are N = 2 independent paths, which are respectively: independent path 1 composed of terminal 1, terminal 6, and terminal 8, and independent path 2 composed of terminal 1, terminal 2, terminal 3, and terminal 5. Calculate the comprehensive occurrence probability A1 of the single-phase ground fault of the L1 distribution line according to the typical example parameters:

[0105]

[0106] This embodiment shows the calculation method of the comprehensive occurrence probability of the fault when there is a false alarm at the terminal. In this embodiment, the comprehensive occurrence probability of the single-phase ground fault of the L1 distribution line is 100%.

[0107] Example 3

[0108] According to a preferred embodiment, as Figure 7 shown, a single-phase ground fault occurs below the terminal 8 of the distribution line L1, terminal 5 gives a false alarm, and terminal 6 fails to report. According to the uplink result, there are N = 2 independent paths, which are respectively: independent path 1 composed of terminal 1, terminal 6, and terminal 8, and independent path 2 composed of terminal 1, terminal 2, terminal 3, and terminal 5. Calculate the comprehensive occurrence probability A1 of the single-phase ground fault of the L1 distribution line according to the typical example parameters:

[0109]

[0110] This embodiment shows the calculation method of the comprehensive occurrence probability of the fault when there are false alarms and missed reports at the terminal. In this embodiment, the comprehensive occurrence probability of the single-phase ground fault of the L1 distribution line is 83.3%.

[0111] Example 4

[0112] According to a preferred embodiment, as Figure 8 shown, a single-phase grounding fault occurs below the terminal 8 of the distribution line L1. The terminal 5 gives a false alarm, and the terminal 1 fails to report. According to the uploaded results, there are N = 2 independent paths, which are respectively: the independent path 1 composed of the terminals 1, 6, and 8, and the independent path 2 composed of the terminals 1, 2, 3, and 5. Calculate the comprehensive occurrence probability A1 of the single-phase grounding fault of the L1 distribution line according to the typical example parameters:

[0113]

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

[0115] Embodiment 5

[0116] According to a preferred embodiment, as Figure 9 shown, when a fault occurs in the distribution line L1, for other distribution lines (such as the Lx distribution line), the terminal 5 gives a false alarm. According to the uploaded results, there is N = 1 independent path, which is composed of the terminals 1, 2, 3, and 5. Calculate the comprehensive occurrence probability A of the single-phase grounding fault of the Lx distribution line according to the typical example parameters X :

[0117]

[0118] This embodiment shows the calculation method of the comprehensive occurrence probability of a fault when there is a false alarm in the non-faulty line Lx. In this embodiment, the calculated comprehensive occurrence probability of the non-faulty distribution line is relatively low.

[0119] Embodiment 6

[0120] According to a preferred embodiment, as Figure 7 shown, a single-phase grounding fault occurs below the terminal 8 of the distribution line L1. The terminal 5 gives a false alarm, and the terminal 6 fails to report. According to the uploaded results, there are N = 2 independent paths, which are respectively: the independent path 1 composed of the terminals 1, 6, and 8, and the independent path 2 composed of the terminals 1, 2, 3, and 5.

[0121] Preferably, allocate the corresponding initial weight coefficient p to each terminal in the independent path in the way of evenly distributing the weight to determine the initial state. Specifically: for the independent path 1 with m = 3, then p1 = p2 = p3 = 1 / 3 = 33.3%; for the independent path 2 with m = 4, then p1 = p2 = p3 = p4 = 1 / 4 = 25%. j That is,

[0122] Furthermore, calculate the comprehensive occurrence probability A1 of single-phase grounding faults in the L1 distribution line according to the above typical example parameters:

[0123]

[0124] At this time, the comprehensive occurrence probability of single-phase grounding faults in the L1 distribution line is 83.33%.

[0125] Preferably, after fault statistics, regularly calculate the comprehensive correct action rate of each terminal according to the actual post-fault action times of the actual distribution terminals. For example, for Terminal 1: 90%, Terminal 6: 50%, Terminal 8: 80%, Terminal 2: 90%, Terminal 3: 90%, Terminal 5: 60%.

[0126] Furthermore, for the independent path 1 containing 3 terminals, calculate the dynamic update weight coefficients of its respective terminals as follows:

[0127]

[0128] In the above formula, P 1_updata is the dynamic update weight coefficient of Terminal 1, P 2_updata is the dynamic update weight coefficient of Terminal 6, P 3_updata is the dynamic update weight coefficient of Terminal 8.

[0129] Furthermore, for the independent path 2 containing 4 terminals, calculate the dynamic update weight coefficients of its respective terminals as follows:

[0130]

[0131] In the above formula, P 1_updata is the dynamic update weight coefficient of Terminal 1, P 2_updata is the dynamic update weight coefficient of Terminal 2, P 3_updata is the dynamic update weight coefficient of Terminal 3, P 4_updata is the dynamic update weight coefficient of Terminal 5.

[0132] Preferably, it can be seen from the above calculation results that for the independent path 1, the weight of Terminal 6 decreases; for the independent path 2, the weight of Terminal 5 decreases. Based on this, p j can be dynamically adjusted, and the comprehensive occurrence probability of single-phase grounding faults in the L1 distribution line can be recalculated based on the adjusted p j The specific calculation method is as follows:

[0133]

[0134] It can be seen from this that in this embodiment, by dynamically adjusting p j, the finally calculated comprehensive occurrence probability of single-phase grounding faults in the L1 distribution line (88.7%) has increased by 5.4% compared to the comprehensive occurrence probability (83.3%) calculated in the initial state. Therefore, when a new fault occurs next time, through the new p j The fault occurrence probability can be calculated more accurately.

[0135] Embodiment 7

[0136] According to a preferred embodiment, as Figure 10 shown, the fault local judgment module distributedly installed on the low-voltage side of the main transformer reports a fault, and at the same time, the fault local judgment modules distributedly installed on the low-voltage sides of each feeder line of the substation do not report a fault. At this time, it is directly reported that a grounding fault has occurred on the substation bus. The power-off auxiliary decision-making system of the present invention can display a power-off prompt interface as Figure 10 shown on the power-off auxiliary decision-making display module, providing bus grounding fault information to the operation management personnel of the local dispatching of the city company without power-off.

[0137] Embodiment 8

[0138] According to a preferred embodiment, a line fault as described in Embodiment 3 above occurs on the L1 distribution line. At this time, the comprehensive occurrence probability of single-phase grounding faults in the L1 distribution line is calculated to be 83.3%. At the same time, there is a false alarm at the off-site terminal on the distribution line L2. At this time, the comprehensive occurrence probability of single-phase grounding faults in the L2 distribution line is calculated to be 12.5%. The power-off auxiliary decision-making system of the present invention can display a power-off prompt interface as Figure 11 shown on the power-off auxiliary decision-making display module, providing power-off decision-making information for the L1 distribution line to the operation management personnel of the local dispatching of the city company.

[0139] It should be noted that the above specific embodiments are exemplary. Those skilled in the art can come up with various solutions inspired by the disclosed content of the present invention, and these solutions also fall within the scope of the disclosure of the present invention and within the protection scope of the present invention. Those skilled in the art should understand that the specification and drawings of the present invention are illustrative and do not constitute a limitation to the claims. The protection scope of the present invention is defined by the claims and their equivalents. The specification of the present invention contains multiple inventive concepts. For example, "preferably" or "according to a preferred embodiment" indicate that the corresponding paragraphs disclose an independent concept. The applicant reserves the right to file divisional applications according to each inventive concept. Throughout the text, the features guided by "preferably" are only an optional way and should not be understood as a must. Therefore, the applicant reserves the right to abandon or delete relevant preferred features at any time.

Claims

1. A single-phase grounding fault substation switching-off method auxiliary decision-making system, characterized in that It includes: The pull-switching auxiliary decision-making data cloud; A fault SMS notification receiving module, which is used to receive various fault information reported by various distribution terminals installed on the distribution line, filter, extract and organize the received "single-phase grounding fault SMS" information into first fault information, and then send the first fault information to the pull-switching auxiliary decision-making data cloud; A fault local judgment module, which is distributed at the distribution line interval of the substation feeder line and / or the low-voltage side interval of the main transformer, and when a single-phase grounding fault occurs below is monitored, it sends the corresponding second fault information and / or third fault information of the installation location to the pull-switching auxiliary decision-making data cloud, where, The pull-switching auxiliary decision-making data cloud is configured as: Form a line number fault set for the first fault information recognized by the fault SMS notification receiving module according to the Lx distribution line to obtain the off-station - Lx distribution line fault set B; Determine the information result of the second fault information recognized by the fault local judgment module, and perform probability calculation on the information result and the off-station - Lx distribution line fault set B with different mathematical weights, so as to calculate the comprehensive occurrence probability of single-phase grounding fault of the Lx distribution line through the built-in fault occurrence probability calculation method.

2. The system according to claim 1, wherein The fault occurrence probability calculation method built in the pull-switching auxiliary decision-making data cloud calculates the off-station distribution line fault probability through the single-phase grounding fault information of the distribution line sent by the off-station distribution terminal, and combines the judgment information generated by the fault local judgment module for monitoring the single-phase grounding fault at the head end of the in-station distribution line, and comprehensively calculates the comprehensive occurrence probability of single-phase grounding fault of the Lx distribution line.

3. The system according to claim 2, wherein The pull-switch auxiliary decision-making data cloud can calculate the comprehensive occurrence probability A of single-phase grounding faults in the Lx distribution line by using the following formula x : A x = P A * A + P B * cal(B) (1) P A +P B = 100% (2) In the above formula, P A is the probability weight assigned to the on-site fault judgment module. A takes a value of 1 or 0. P B is the probability weight assigned to the fault SMS notification receiving module. cal(B) is the probability calculation for the "off-site - Lx distribution line fault set B".

4. The system according to claim 3, characterized in that, The pull-switching auxiliary decision-making data cloud can determine the weights of P A and P B in a fixed allocation method or a dynamic allocation method. When using the dynamic allocation method, the pull-switching auxiliary decision-making data cloud can first perform system initial settings according to the fixed allocation method, and then make dynamic adjustments based on the calculation results of the historical action success rates of the fault local judgment modules for monitoring the in-station first-end distribution lines. The calculation formula is as follows: P A ≤P Amax (4) In the above formula, N represents the total number of historical judgments of the fault local judgment module for monitoring the in-station first-end distribution line, m represents the total number of correct historical judgments of the fault local judgment module for monitoring the in-station first-end distribution line, k is a coefficient used to adjust the calculation result, and P Amax is P A 's upper limit setting.

5. The system according to claim 3, wherein The pull-switching auxiliary decision-making data cloud can perform probability calculation on the "off-station - Lx distribution line fault set B" through the following formula: In the above formula, N is the number of independent paths of the terminals that have reported single-phase grounding fault information existing in the "off-station - Lx distribution line fault set B"; m represents the total number of levels on a certain independent path; p j represents the weights corresponding to different levels in the independent path. On an independent path, j represents the j-th level on the independent path; a ji represents the result reported by the power distribution terminal at the j-th level on the i-th independent path.

6. The system according to claim 5, wherein The pull-switching auxiliary decision-making data cloud can first set the initial state of p j and then dynamically adjust it. Among them, the pull-switching auxiliary decision-making data cloud can set the initial weight coefficient of p j in an evenly distributed manner, and then regularly calculate the dynamically updated weight coefficient of each terminal according to the actual number of correct post-event actions of the actual power distribution terminals, so as to realize the dynamic adjustment of p j .

7. The system according to claim 1, characterized in that It also includes a pull-switching auxiliary decision-making display module, which is used to dynamically display the result calculated by the pull-switching auxiliary decision-making data cloud, so as to provide clear and definite pull-switching auxiliary decision-making information for the operation and management personnel of the local dispatching.

8. The system according to claim 7, wherein The pull-switching auxiliary decision-making 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 of not receiving the first fault information, and send the result to the pull-switching auxiliary decision-making display module, so as to dynamically display the grounding fault information of the bus Mx through the pull-switching auxiliary decision-making display module, prompting the operation and management personnel of the local dispatching to search for the fault of the bus Mx without performing the pull-switching operation.

9. An auxiliary decision-making method for the single-phase grounding fault substation's line-switching method, characterized in that, It includes the following steps: Form a line number fault set for the first fault information according to the Lx distribution line to obtain the off-station - Lx distribution line fault set B; Determine the information result of the second fault information, and perform probability calculation on the information result and the off-station - Lx distribution line fault set B with different mathematical weights, so as to calculate the comprehensive occurrence probability of single-phase grounding fault of the Lx distribution line through the fault occurrence probability calculation method.

10. The method according to claim 9, wherein The failure probability calculation method used is to calculate the failure probability of the off-station distribution line through the single-phase grounding fault information sent by the off-station distribution terminal, and combine the judgment information generated by the on-site fault judgment module for monitoring the single-phase grounding fault at the head end of the in-station distribution line to comprehensively calculate the comprehensive occurrence probability of the single-phase grounding fault of the entire Lx distribution line.

Images