30results about How to "Solve the problem of fault location" patented technology

The invention relates to a single-phase earth fault location system for a distribution network of a power system and a method thereof. The single-phase earth fault location system comprises a pulse signal generator, which is arranged between the neutral point of a main substation transformer and the ground, and the initial end of each outlet branch is provided with a current sensor; and a main station is also mounted in a substation, and is communicated with the current sensors. The method installs the thyristor-based short-circuit current generator at a corresponding position in the substation, thyristors are controlled to instantaneously conduct in order to generate and inject short-circuit current into a faulty line, the sensors mounted on the initial ends of the outlet branches detectthe short-circuit current, each sensor detecting the short-circuit current informs a host positioned in the substation of own state information via communication, and according to calculated fault impedance coupled with the locations of the sensors detecting the short-circuit current, the host determines the location where a single-phase earth fault occurs.

The method includes following steps: collecting data in order to obtain signals of voltage and current at multiple ends of tested wires; recording and exchanging electrical data before and after fault in order to obtain needed data to locate position of fault; localization of fault obtaining accuracy position of fault point. Basic reason for the method is as follows: criterion of branch, where fault occurred, is derived for transmission lines in T type connection through theoretical analysis; based on Kirchoff law, differential equation relation of electrical data at three ends of T type connection is obtained; issue of localization of fault for transmission lines in T type connection is translated to issue of localization of fault for double ends system. Thus, using method for localization of fault for double ends system existed or recommended in the invention locates fault point so as to solve issue of localization of fault for transmission lines in T type connection.

The invention provides a multi-sensor fusion type fault locating method for a gearbox of a wind turbine generator. The multi-sensor fusion type fault locating method for the gearbox of the wind turbine generator comprises the seven steps that firstly, application conditions of a fault locating model are determined according to the inner structure of the gearbox and the positions and the number of vibration sensors; secondly, collected vibration signals are analyzed according to an existing fault diagnosis technology, and corresponding fault characteristic values are extracted; thirdly, a relation between a faulty component and a characteristic value set is established according to the parsimonious covering theory; fourthly, the position, the type and the degree of the fault of the gearbox are determined according to a gearbox endoscopy result; fifthly, the influences of different faulty components on vibration signals of multiple detecting points are analyzed, and a vibration attenuation coefficient is obtained; sixthly, fault diagnosis is conducted on obtained data according to the difference between the fault characteristic values and the BP neural network algorithm, and the fault is located to the component of a certain type; seventhly, the attenuation coefficient beta' k of the vibration signals are obtained and analyzed, and the position of the faulty component is determined by working out the smallest error delta with a comparison method, wherein delta=beta' k-beta k.

The invention discloses an undercurrent grounding system fault positioning method suitable for monitoring a branch line, belongs to the field of fault detection of a power distribution network, and brings forward a positioning method for determining a search path and finding out a fault section step by step through integrated utilization of a similarity and polarity relation between transient zero-mold currents of each monitoring point of the upstream and downstream of each section, for solving the problem of positioning a single-phase grounding fault in an undercurrent grounding mode distribution system for monitoring a branch line through a terminal. According to a fault line selection result, first of all, a first section of a fault line outlet is selected as an undetermined section, a correlation coefficient between the transient zero-mold currents of each monitoring point of the upstream and downstream of the undetermined section is calculated, and whether the undetermined section is a fault section is determined according to the correlation coefficient and a polarity feature; and if the undetermined section is a sound section, a next undetermined section is determined according to the amplitude size of the transient currents until the fault section is found. According to the invention, in actual application, the power distribution network has too many branches. The method provided by the invention solves the positioning problem in the distribution system for monitoring the branch line through the terminal and has a wide actual application value.

The invention relates to an overhead power distribution line single-phase grounding fault positioning method based on space magnetic field waveform characteristics, and belongs to the technical field of faults of an electric power system. The method includes arranging fault indicators and positioning faults by a time-difference-of-arrival method through a mobile measurement device. When a power distribution line is in heavy-current (>/=7A) fault, the fault indicators act to realize positioning of faults correctly; and when the power distribution line is in low-current (<7A) fault, the fault indicators do no actions, fault branches are cut off from branch points, and single-peak pulse signals are injected into a transformer substation. The method has high accuracy and can be used for solving the problem about positioning of overhead power distribution line single-phase grounding faults, and has important application in the technical field of fault detection of the electric power system.

The invention discloses a fault positioning method used for a power distribution network and comprising multiple T-connection inversion distributive power sources. The method includes steps of electrifying a relay protection device; initiating circuit parameters; acquiring power of the distributive power sources; acquiring voltage phasor and current phasor on two sides of a feed line; calculating output current of the distributive power sources; calculating the magnitudes of comparison voltage on two sides of the feed line; if the comparison voltage is greater than a setting value, determining faults within a feed line zone and starting a fault positioning algorithm; if the faults occur in a specific section, calculating a measurement distance percentage, and determining the faults within the section if the measurement distance percentage is smaller than 100%. By adopting the method, problems in relay protection and fault positioning when the multiple distributive power sources are in T-connection with the circuit can be solved effectively. Besides, the method is insusceptible to influence by connection number and connection position of the distributive power sources, fault types and transition resistors, and is high in adaptability and engineering practicality.

The invention provides a data mining-based power distribution network fault precise localization method. Data mining is introduced into the power grid dispatching field; based on Fourier analysis on historical fault trips, a clustering algorithm is adopted to establish the vector cluster of fault trip locations; the location of a tripping switch on which a new fault occurs is judged through calculating the similarity between the fault frequency domain characteristic vector of the new fault and the characteristic vectors of each cluster; and a fault range is locked based on the location of the tripping switch. According to the method, the range of an actual fault is judged through the change of the electric quantity of a high-voltage level outgoing switch, and therefore, the problem of incomplete coverage of special data dispatching networks in China can be solved, especially, problems in fault localization of an urban distribution network and a rural power grid can be solved, accident processing time for the faults of the distribution network and the rural power grid can be shortened, and power outage time can be reduced.

The invention discloses a small current grounding fault line selection method based on generalized S transformation transient energy. The method comprises the steps that: according to a 10kV line topological graph of a power distribution network, an actual overhead line-cable series-parallel line model and a fixed-value resistance fault model of the power distribution network are built on a PSCADplatform, and single-phase earth fault simulation experiments under various simulation working conditions are carried out; and then generalized S transformation is performed on the acquired transientzero-sequence current at the bus outlet in 1/4 power frequency period after each feeder line fails, generalized S transformation transient energy in a characteristic frequency band is calculated, andthe transient energy of each feeder line is compared so as to adaptively select a faulty line. The method is not influenced by the working conditions such as the fault position, the fault resistance,the line structure and the neutral point grounding mode, the fault line can be accurately selected; and the method has the advantages of being high in practicability, high in accuracy and wide in applicability.

The invention provides a status monitoring method for a spark gap trigger circuit, which includes the steps: monitoring normality of a path of signal transmitted by a control protector; detecting the status of a trigger instruction output end of a programmable device logic circuit or the status of a trigger output end of a spark gap trigger device; subjecting the detected status signals to digital filtering; broadening narrow-pulse status signals obtained by filtering; and allowing a programmable device to transmit collected status marking signals to the control protector. By the method, the status of the gap trigger circuit can be determined timely and accurately; transient trigger pulse is detected at the trigger output end of the spark gap trigger device; transient status information is reliably transmitted to the control protector in milliseconds; and accordingly the problem of locating failure of the spark gap trigger circuit is well solved, and field debugging and maintenance of the spark gap circuit are facilitated greatly.

The invention discloses a power distribution network fault distance measurement method based on traveling wave signals generated during closing of a circuit breaker. The power distribution network fault distance measurement method comprises the steps of: analyzing the transmission characteristics of the traveling wave signals generated during closing power transmission after the circuit breaker is disconnected when a single-phase grounding fault occurs in a power distribution network, finding that traveling wave disturbance signals generated at the closing moment of the circuit breaker can serve as injection signals, and estimating the position of a fault point by using a traveling wave distance measurement method. The traveling wave signals have obvious characteristics and have relatively high accuracy when being used as measurement signals of a single-ended method. Meanwhile, the method does not need the investment of synchronous time synchronization equipment, and the distance measurement is carried out in the open-end operation of the circuit breaker when a conventional line fault occurs, and is not influenced by a neutral point grounding mode. The fault positioning problem of the power distribution network can be effectively solved, and the influence of transition resistance is small.

The invention discloses a diagnosis system and method for fault classification and positioning of a transformer winding. The system comprises a sweep generator, a transformer winding, a detection terminal, an inductor L1, a divider resistor R1, a divider resistor R2 and a capacitor C. The sweep generator outputs a sweep-frequency signal, the sweep-frequency signal is input to the transformer winding from a grounding point N through the inductor L1 and the divider resistor R1, flows through a high-voltage winding A in the transformer winding and is output, and after the sweep-frequency signal passes through a capacitor C and is divided by the divider resistor R2, sweep-frequency data is collected by the detection terminal; and the detection terminal diagnoses the fault type and position of the transformer winding through a constructed deep learning convolutional neural network model. According to the method, the fault positioning problem is solved on the basis of realizing high-precision fault type diagnosis, and the method has certain engineering significance. The method and the system have a good effect on a simulation sample constructed in the invention, the fault type diagnosis precision is up to 100%, and the fault positioning accuracy is up to 83.33%.

The invention discloses a fault positioning method under encrypted communication of a transformer substation. The technical scheme adopted by the invention is as follows: after a communication initiator and a communication receiver establish an encryption channel by adopting an authentication encryption technology, replacing an encryption key for communication periodically after data with a fixed length is transmitted; meanwhile, monitoring abnormal information in the communication process in real time in an application layer; when any communication exception occurs, accurately describing exception information and encoding the exception information into an exception notification message, and immediately sending the exception notification message which can be captured by network message collection equipment in a plaintext mode; and when any one of the communication sender and the communication receiver monitors the communication abnormality of the specific abnormality level, automatically triggering log recording of the abnormal information. According to the method, the fault positioning capability under the communication abnormal condition in the authentication and encryption communication environment in the transformer substation is improved, and the difficulty of operation and maintenance management of communication in the transformer substation is reduced.

The invention discloses a multi-source power distribution network fault positioning method based on an improved Jaya algorithm in the field of power distribution network fault positioning, and the method comprises the steps: S1, building a fault positioning model according to the characteristics that an active power distribution network contains a plurality of distributed power supplies, and setting a fault current information coding scheme; and establishing a switching function and forming a model evaluation function. S2, carrying out optimization processing on the Jaya algorithm, wherein the optimization processing comprises the steps of optimizing random number generation of variable position iteration based on a chaos theory; performing variable correction on individual codes; and S3, based on the model in the S1, solving calculation is carried out through the improved algorithm in the S2. According to the method provided by the invention, the fault positioning problem of single and multiple faults in different distributed energy distribution conditions can be realized, the fault positioning containing simple distortion information can be processed, the fault section positioning speed when the power distribution network has a fault can be improved, and the reliability of a power system can be improved.