91 results about "Minimum cut set" patented technology

The invention provides a power grid topology based power system reliability calculation method. The method includes the following steps: determining input data of power grid topology; forming a minimal path set matrix of the power grid topology; outputting a minimum cut set of the power grid topology; and calculating reliability of a power system via the minimum cut set. The power grid topology based power system reliability calculation method has the advantages that in consideration of expanded faults caused by component faults of a disconnector, a busbar and the like, automatic search is performed to form an expanded fault failure table; multiple situations of source/sink, parallel branches and source and sink coincidence can be processed; programs can be configured according to practical situations, and a branch cut set, a node cut set and a branch and node hybrid cut set of the system are solved; and impact on the system due to expanded fault branches can be processed.

The invention provides a fault tree-based coal mine underground combination switch fault diagnosis method, which is implemented by a combination switch control system, wherein the combination switch control system comprises a central controller, a loop comprehensive protector and a man-machine interface. The fault tree-based coal mine underground combination switch fault diagnosis method comprisesthe steps of: establishing a fault tree rule; determining top events, middle events and bottom events according to rules and according to expert experience, case summary and combination switch principle analysis, and establishing a fault tree; triggering a diagnosis mechanism by the central controller according to an occurred fault phenomenon, and quickly obtaining a minimum cut set of the faulttree by utilizing a mutual exclusion rule of process nodes at the same layer; solving the importance of each bottom event in the minimum cut set, and outputting diagnosis results according to the order of the importance; and determining a fault reason according to the bottom event corresponding to the diagnosis result, and adding one to the accumulated times of the bottom event corresponding to the fault reason for calculating a dynamic correction score of the bottom event next time. Through adoption of the fault tree-based coal mine underground combination switch fault diagnosis method, the fault position of the combination switch can be rapidly judged, and the fault can be conveniently and rapidly eliminated.

The invention discloses an incompatible failure safety analysis system and method for an airplane motor, and belongs to the technical field of special risk analysis and evaluation of an airplane. The incompatible failure safety analysis system of the airplane motor comprises a demand information processing module, a parameter setting module, and an analog simulation and result output module. The incompatible failure safety analysis method for the airplane motor comprises the following steps: determining position parameters and size parameters of fragments of an airplane motor rotor relative to a digital mock-up of the airplane; detecting airplane models which have a possibility of having failures caused by the fragments of the airplane motor rotor with a region division and hierarchical bounding bolumes within a failure fragment reachable region, and distinguishing Catastrophic function risks and rationally providing analysis results of the incompatible failure safety of the rotors by carrying out the Boolean operation on a simulation result matrix and minimum cut sets. The incompatible failure safety analysis system and method disclosed by the invention can rapidly and accurately distinguish the potential risks of the incompatible failures of the rotor in an airplane design section, and provides the technical support for the safety design and the configuration design of an airplane system.

The invention relates to a fault tree diagnosis method for a typical fault of a reciprocating compressor coupled to a triangular fuzzy number. The method comprises the steps of (1) classifying variousfault types with each key component as a research object according to an operating mechanism of the reciprocating compressor, and establishing a fault tree of the reciprocating compressor typical fault, (2) establishing a minimum cut set of top-level events according to the logic relationship of upper and lower events of the fault tree, (3) determining the probability of occurrence of fault treetop-level events and each node layer event by combining the triangular fuzzy number, and (4) judging the location of a key component of a compressor fault according to measured data of characteristicparameters and according to the logic relationship and outputting a fault mode. According to the method, the probability that a triangular fuzzy function expresses a fault event is integrated into a fault tree diagnosis method, a multi-factor feature causing the fault is reflected, and probability assignment is allowed to have a certain degree of error. The method has the advantages of convenientapplication, high diagnostic accuracy and high reliability.

The invention discloses a method for determining the reconfigurability of a satellite control system. The method comprises the following steps of: (1) constructing a satellite control system function tree and connecting the different levels of the function tree by means of AND Gate or OR Gate according to the function implementation mode of the satellite control system; (2) according to the AND/OR relationship between different levels of the function tree, determining the cut-set family C of the function tree by using the descending method or the ascending method, wherein the elements of the cut-set family are cut-sets and the cut-sets are component sets for implementing the functions of the satellite control system; (3) performing absorption treatment on the cut-set family C determined in the step (2) to obtain the minimum cut-set family Cmin of the function tree, wherein the elements of the minimum cut-set family Cmin are minimum cut-sets cmin and the minimum cut-sets cmini are the sets of least components required for implementing the functions of the satellite control system; (4) performing failure mode effect analysis (FMEA) on the satellite control system to determine the failure mode, failure occurrence probability and failure severity of the satellite control system; (5) determining the reconfigurable degree (Gamma-i) of the failure mode i; and (6) determining the reconfigurable rate of the satellite control system.

The invention discloses a track circuit red-light strip default diagnosis method based on the FTA and a multilevel fuzzy-neural sub-network. The establishment of a default diagnosis module mainly comprises flowing steps of (1) FTA qualitative analysis for determining a default tree module according to default investigation and analysis and using the descending method to search the minimum cutset; (2) FTA quantitative analysis for solving probability of occurrence of an intermediate event and a top event according to probability of occurrence of a bottom event obtained according to the investigation and analysis and applying the Fussell method to analyze the importance degree of the minimum cuset; (3) extracting default diagnosis rules by analyzing knowledge contained in the default tree; (4) designing a diagnosis system structure and constructing a multilevel fuzzy-neural sub-network module according to the FTA analysis results; (5) setting fuzzy subordinating degree function parameter according to a to-be-diagnosed object, and adjusting network weights via sample learning and training so as to determine a default diagnosis module; and (6) inputting the measured data into the default diagnosis module in the actual running so as to obtain default diagnosis results via calculation. The track circuit red-light strip default diagnosis method can be used for automatically positioning a default point rapidly during a ZPW-2000 non-insulated frequency shift track circuit red-light strip default.

The invention discloses an accident tree graph digital analysis method and an accident tree graph digital analysis tool both applied to coal mine safety evaluation. The method includes the following steps: building an accident tree graph, particularly, creating a graph element library, building an accident tree graph and digitalizing the accident tree graph; analyzing and simplifying the accident tree graph, particularly, analyzing the accident tree graph and simplifying the same; building an accident tree parameter calculating model, particularly, building a minimum cut set calculating model, building a minimum radius set calculating model, building a top event occurrence probability calculating model and building a three importance degree coefficient calculating model. The tool includes an accident tree graph building module, an accident tree graph analyzing and simplifying module and an accident tree graph parameter calculating model building module. The accident tree graph digital analysis method and the accident tree graph digital analysis tool both applied to coal mine safety evaluation have the advantages that by the method, defects of low efficiency and high error rate caused by manual drawing of the accident tree graph, manual building of a structure function and manual building of calculating models are overcome, so that calculating results are more accurate and convenience is brought to taking more effective measures; the tool provides a guarantee for implementation of the method.

The invention discloses a turnout fault early warning method. The method comprises the following steps that S1, basic events of faults in a turnout system are determined according to abnormal information of equipment in the turnout system; S2, turnout fault expression is used as a top event, a fault tree of the top event is built according to the basic events, and minimum cut sets of the fault tree is acquired through Boolean calculation; S3, the fault tree is traversed based on status information uploaded by the turnout system, whether some status information corresponds to the minimum cut sets of the fault tree or not is determined, and a bottom event of the minimum cut sets corresponding to the status information is used as early warning information and is provided for a user. According to the turnout fault early warning method, the faults of the turnout equipment in rail transit facilities are analyzed through the fault tree, all possible fault modes are determined, fault sources and fault causes are indicated, and accordingly the faults of the turnout equipment can be detected in an on-line mode, the user can be warned and maintenance suggestions can be provided for the user.

The invention relates to a data-driven fault-tree analysis method, a data-driven fault-tree analysis device and data-driven fault-tree analysis equipment. The data-driven fault-tree analysis method can include the steps of: generating a fault tree, which corresponds to a fault top event, according to historical fault data of the fault top event, wherein the fault tree includes multiple layer bottom events; quantitatively processing the fault tree to obtain fault probability corresponding to each layer bottom event and a Fussell-Vesely importance degree of each minimum cut set, wherein the minimum cut sets are cut sets which are obtained by qualitatively processing the fault tree and correspond to the fault top event; and generating state evaluation data of to-be-analyzed equipment according to each fault probability and each Fussell-Vesely importance degree. By adopting the method, fault management efficiency is improved, and reliability of equipment fault management is also improved.

The present invention is a minimum cut set calculation system for calculating minimum cut sets of a fault tree with binary decision diagram (BDD), comprising: subtracting means for, from one of two sub-BDDs of an input BDD, removing redundant paths included in the other sub-BDD using a recursive function comprised of a recursive case and a base case, wherein said subtracting means comprises equivalence removing means for, when said two sub-BDDs are equivalent, outputting a terminal node 0 in said base case.

The invention provides a fault rate statistical method and system for a wind turbine generator. The method comprises the following steps: according to a pre-established fault tree model of a wind turbine generator, carrying out qualitative analysis on faults of the wind turbine generator to obtain a minimum cut set of a fault tree; Acquiring fault time sequence information of the wind turbine generator; according to the fault time sequence information, establishing a fault distribution function model by referring to a minimum cut set of a fault tree model; and calculating the top event probability, the probability importance degree, the structure importance degree and the key importance degree of the wind turbine generator fault according to the fault distribution function model of the wind turbine generator. According to the fault rate statistical method and system for the wind turbine generator, an effective means for quantitative analysis is provided for the fault rate of the wind turbine generator, and effective technical support is provided for improving the fault handling capacity of on-site maintenance personnel.

The invention provides a method for determining importance degree of components of a satellite control system. The method includes: (1) a satellite control system function tree is established, and different levels of the function tree are connected through a conjunction gate or a disjunction gate according to function realization ways of the satellite control system; (2) a cut set family C of the function tree is determined by adopting a descending method or an ascending method according to the conjunction or disjunction relationship among the different levels of the function tree, elements in the cut set family are cut sets, and the cut sets are sets of components for achieving functions of the satellite control system; (3) absorption processing is performed on the cut set family C determined in the step (2), a minimum cut set family (Cmin) of the function tree is obtained, elements in the minimum cut set family (Cmin) are minimum cut sets cmin, and the minimum cut sets cmin are sets of minimum components required for achieving the functions of the satellite control system; and (4) the importance degree of each component in the function tree is determined. The method overcomes the defect that a failure mode and effects analysis (FMEA) technique can only show single point failure and can provide a basis for design of reliability and reconfigurability of a satellite.

The invention provides a frequency spectrum resource distribution method based on topology control in a cognitive radio network. The method comprises a static state distribution method with a relatively long execution period and a dynamic distribution algorithm with a relatively short execution period, the static state distribution method comprises steps of finding an approximation algorithm of a minimum spanning tree of a maximum node degree, distributing frequency bands to links in the network according to the spanning tree, distributing distribution algorithms of additional frequency bands to a minimum cut set related with a node; the dynamic distribution algorithm comprises steps of acquiring a present network flow distribution situation, changing a frequency band distribution structure according to the present network flow distribution situation to meet present communication requirements. The method can improve robustness and capacity of a secondary user network, has relatively low calculation complex degree and optimizes performance of the cognitive radio secondary user network.

The invention relates to a method for quickly solving minimum cut sets of micro-grids on the basis of breadth first search. The method includes establishing structural topological diagrams of the micro-grids so as to obtain network node diagrams; grading various nodes by the aid of Breadth First Search and creating grade matrixes; creating root-leaf matrixes and separating the directly connected nodes according to different grads and root-leaf relations; creating selected matrixes and storing all possible cut sets. Each cut set is represented by a row vector.

The invention provides a microgrid fault prediction method and device and electronic equipment. The method comprises the steps: obtaining a fault tree model of a microgrid; calculating a minimum cut set and a minimum path set of the fault tree model; calculating the importance degree of the occurrence of a top event according to the calculated minimum cut set and minimum path set when each basic event happens; performing the ordering of all basic events based on the importance degree of the occurrence of the top event when each basic event happens to obtain an ordering result; sequentially detecting all basic devices in the microgrid according to an ordering result, thereby achieving the prioritized detection of the basic devices with the higher importance degrees, achieving the quick locating of fault equipment, and saving time and labor.

The invention discloses an automatic section search method based on a cut set search algorithm. The method is characterized in that the power transmission sections of a power grid are divided into initial sections, power transmission sections and key sections and includes: MATLAB reads basic data from PSASP and uses the read basic data to obtain the topological graph of the power grid, that is tosay, an adjacent matrix is obtained; the cut set search algorithm based on connectivity judgement is used to obtain the minimum cut set of the whole power grid, that is to say, the initial sections are obtained; screening the power transmission sections from the initial sections according to current directions and on-off distribution factor constraint conditions; calculating the safety margin of the power transmission sections, judging whether the safety margin of the power transmission sections is smaller than a threshold or not, and if so, the power transmission sections are selected as thekey sections; outputting all the key sections. By the method, missing of important sections can be avoided, and the time of operation staff can be saved.

The invention discloses an improved method for fault diagnosis of the red band of a track circuit. The method includes the following steps of: 1) qualitative analysis of FTA for establishing a fault tree model according to field failure analysis; 2) determining the diagnostic attribute of a diagnostic model by a minimum cut set and extracting a fault diagnosis rule by analyzing knowledge contained in the fault tree; 3) designing a diagnostic system structure and constructing an improved particle swarm optimization support vector machine (SVM) model according to a FTA analysis result; 4) setting up an improved particle swarm optimization algorithm parameter according to a diagnostic object, and establishing a fault diagnosis model through the SVM model improved by sample learning and training; and 5) inputting actual measured data in real operation into the fault diagnosis model and obtaining a fault diagnosis result by calculation. The method can be used for diagnosing the red band failure of a ZPW-2000 non-insulated frequency shift track circuit, and is high in fault diagnosis accuracy and high in fault sample utilization rate so as to provide a new technical means for the intelligent fault diagnosis of the track circuit.

The invention relates to a power system safety determination method, comprising: determining the type of each element included a power system and topological structure of the power system, and sorting reliability historical data; determining a minimum path set of the topological structure of the power system; determining a minimum cut set of the topological structure of the power system; determining, through the minimum cut set, a power system reliability index in connection with the reliability historical data; in connection with element reliability historical data, using calculated unavailability of elements with lowest reliability in the power system as a determination threshold, and comparing the power system reliability index with the determination threshold to determine whether power system safety is satisfactory or not; the technical scheme provided herein makes considerations for the influence of faults of various elements upon system safety, such as breakers, disconnectors, busbars, and circuitry, and the method is suitable for discovering weak links of a power system to improve safety and provide beneficial support for power grid planning decision.

An improved availability evaluation method for a nuclear power design phase comprises S1, screening out a system in which a fault may cause the reactor tripping and the turbine tripping of a unit; S2,performing FMEA analysis on the equipment in the system screened out in the step S1 to determine all single and dual failure modes that cause the reactor tripping and the turbine tripping of the unit; S3, taking an event that the system is unavailable and causes the unit to stop and reduce the power as a top event, and for each failure mode, determining the minimum cut set by fault tree modeling;S4, determining a failure rate and a mandatory unavailable time of each minimum cut set; S5, calculating an annual unplanned shutdown frequency of a nuclear power plant by using the failure rate of each minimum cut set and the annual number of times/annular time of the fault; and calculating the annual mandatory unavailable time of the nuclear power plant based on the failure rate and the mandatory unavailable time of each minimum cut set; and S6, determining the availability of the nuclear power plant based on the annual unplanned shutdown frequency and the annual mandatory unavailable time.The method can quantitatively predict the availability of the nuclear power plant.

The invention discloses a three-dimensional image segmentation system and a segmentation method thereof. The segmentation method comprises steps of: selecting an image with a frame so as to obtain a target image including a target object; according to the target image, establishing a foreground model and a background module; calculating undirected connected graphs and undirected weighted graphs of the foreground and the background; assigning weight value to the undirected connected graphs so as to obtain weighted undirected connected graphs; calculating a minimal cutest of the undirected weighted graphs; and segmenting the weighted undirected connected graphs according to the minimal cutest so as to obtain two unconnected sub graphs, thereby achieving segmentation of the foreground and the background of the target image. According to the invention, three-dimensional medial image data can be directly segmented; used time is short, segmentation precision is high, the robustness of the segmentation results is good and a cavity phenomenon will not be caused; and in addition, the visualization effect of the three-dimensional image segmentation system and the segmentation method thereof is good, image noise can be effectively eliminated and the edges of the segmented images are quite smooth.