195 results about "Transmission line protection" patented technology

The invention discloses an ultra high-voltage alternating current transmission line protection method based on an all-component differential coefficient matrix, comprising the following steps that the fundamental frequency electric amount on both ends of an ultra high-voltage alternating current transmission line is measured; the positive, negative and zero sequence current amount on the other end is calculated from that on one end of the line with a long line equation; the fundamental frequency current amount on the other end is calculated through a symmetrical component method; and then a differential coefficient matrix is calculated. A fault type is judged according to the values of all elements of the differential coefficient matrix, and a fault phase is enabled to be correctly tripped. The method is applicable to protecting the whole fault process of the ultra high-voltage alternating current transmission line; and particularly when the ultra high-voltage alternating current transmission line has a single-phase high-resistance grounding short-circuit fault, the method can accurately identify and correctly trip the fault phase, and circuit breakers on both ends of other two normal phase lines are reliable without working.

The invention discloses a UHV DC transmission line protection method utilizing current abrupt change characteristics based on a distributed parameter model. The UHV DC transmission line protection method comprises the steps of processing voltage and current signals measured by transformers at both ends of a DC line by means of an intelligent electronic device (IED), and identifying internal and external faults according to polarities of current abrupt variables. The UHV DC transmission line protection method adopts a distributed parameter model for carrying out distributed capacitive current compensation, eliminates the influence of asynchronization of the distributed capacitive current and data. A protection criterion selects components with the frequency band of [0,100] Hz in current information, avoids the electromagnetic coupling between DC side characteristic harmonics and a bipolar DC line and the influence of lightning interference. The polarities of current abrupt variables at both ends of the line are Boolean quantities, and the communication traffic of longitudinal channels is small. The UHV DC transmission line protection method utilizing the current abrupt change characteristics based on the distributed parameter model only utilizes polarities of the current abrupt variables for identifying the internal and external faults, is simple in principle and small in communication traffic, and is stable and reliable.

The invention discloses a method for analyzing ultra-high voltage direct current system lockout caused by a lightning stroke of an electric transmission line. The method comprises the first step of summarizing electric quantity characteristics and direct current circuit protection action characteristics in the lightning stroke lockout process, the second step of establishing an ultra-high voltage direct current system lightning stroke simulation model, the third step of establishing a converter station measuring system simulation model, the fourth step of establishing a control system and circuit protection simulation model, the fifth step of combining the three simulation models to form a closed loop real-time simulation system, and the sixth step of studying the ultra-high voltage direct current lockout situation caused by the lightning stroke by utilizing the simulation system. A lightning stroke simulation modeling method of an ultra-high voltage direct current power transmission system in a circuit with the length reaching to thousands of kilometers is put forward, the coupling real-time simulation of the lightning stroke simulation model and the circuit protection simulation model is achieved, and an effective means is provided for studying the ultra-high voltage direct current system lightning stroke lockout mechanism and optimizing the direct current transmission line protection definite value.

The invention provides a method and apparatus for detecting communication channel delay asymmetry between transmission line protection devices. The method comprises: calculating, repeatedly, clock disparity between clocks of the protection devices and communication delays at different paths of the communication channel; comparing the latest calculated clock disparity and communication delays with previously calculated clock disparities and communication delays, respectively; determining a channel switching has happened if a change of the calculated clock disparity exceeds a first threshold, or a change of the calculated communication delays for any path exceeds a second threshold; and determining the channel delays as asymmetrical if a difference between the calculated communication delays of the different paths after the channel switching exceeds a third threshold.

The invention belongs to the technical field of hidden trouble prediction and management for trees in the channel of an overhead transmission line and specifically relates to a tree obstacle hidden trouble automatic pre-warning system for an overhead transmission line and a pre-warning method for the above system. The method comprises the steps of carrying out the field survey to conduct the data statistics on the hidden troubles of trees in an overhead transmission line protection zone and construct a hidden trouble database for trees in the channel of an overhead transmission line; conducting the traversing treatment on all trees in the tree hidden trouble database at regular intervals; for any tree with a hidden trouble, calculating the current distance between the tree and a corresponding conductive wire, judging the type of the tree hidden trouble, automatically pre-warning, dynamically evaluating the risk of the hidden trouble according to provisions on the safe operation of the overhead transmission line, and dynamically updating the hidden trouble data of the tree in real time. According to the invention, the problem that existing tree obstacle hidden trouble-shooting methods are time-consuming, labor-consuming and easily cause the artificial misjudgment can be solved. Meanwhile, the pre-warning information is provided timely. The damage to both the personal safety and properties, due to the occurrence of tree obstacle hidden hazards, can be prevented.

The invention disclose a high-voltage DC transmission line protection method based on the waveform similarity of traveling waves, and relates to the field of high-voltage DC transmission line fault detection. The similarity between the waveform of a rectification side linear-mode forward traveling wave and the waveform of an inversion side linear-mode backward traveling wave of a DC transmission line is high when a fault occurs outside the area, and the similarity is low when a fault occurs inside the area. The voltage and current of the rectification side and the inversion side are respectively collected, and the rectification side linear-mode forward traveling wave and the inversion side linear-mode backward traveling wave are obtained by calculation; the start of protection is detectedby using the voltage gradient; after the protection is started, the linear-mode forward traveling wave is transmitted to the inversion side at the rectification side, and the liner-mode backward traveling wave is transmitted to the rectification side at the inversion side; the improved DTW distance between the rectification side linear-mode forward traveling wave and the inversion side linear-modebackward traveling wave is calculated respectively at the rectification side and the inversion side, and a fault criterion of the DC transmission line is established. The method can accurately identify various faults of the DC transmission line, and has good synchronous resistance, strong transition resistance and certain noise and abnormal data resistance.

The invention discloses a single-end distance measurement method for an electric transmission line single-phase earth fault. The method comprises the following steps: calculating equivalent resistance by using fault phase electric quantity in the electric transmission line protection installing place, multiplying the equivalent resistance by fault phase negative sequence current to acquire the single-phase earth fault point voltage, calculating a real part of a ratio between single-phase earth fault point voltage and electric transmission line voltage drop per unit length to acquire an additional fault distance caused by transition resistance, and using the real part of the ratio to subtract the additional fault distance so as to acquire a fault distance from the electric transmission line protection installing place to the single-phase earth fault point. According to the method, the problem about the effect of transition resistance on single-end fault distance measurement accuracy is solved, higher distance measurement accuracy is achieved in case of electric transmission line single phase high resistance ground fault, the distance measurement principle is simple, the process is easy to realize, the fault distance is directly calculated without adopting the search algorithm, the distance measurement speed is high, and the instantaneity is high.

The invention provides a transmission line protection method and a transmission line protection device. The transmission line protection method comprises the steps that three voltage equivalent travelling waves of three voltage fault transient traveling wave phasors on one end of a transmission line are constructed, and three current equivalent travelling waves of three current fault transient traveling wave phasors on one end of the transmission line are constructed; the polarity of three voltage equivalent travelling waves and the polarity of three current equivalent travelling waves are acquired; according to the polarity of three voltage equivalent travelling waves and the polarity of three current equivalent travelling waves, whether one end of the transmission line has a forward fault is determined; if the fact that one end of the transmission line has the forward fault is determined, whether the other end of the transmission line has a forward fault is determined; if the determining result is yes, the transmission line is cut off to protect the transmission line. According to the technical scheme of the invention, whether the transmission line has a line fault can be quickly detected, and appropriate measures are taken to effectively improve the protection reliability of the transmission line.

A method for determining transient errors in an unsynchronized, digital current differential transmission line protection system includes receiving a first current phasor measurement at a time, t, and receiving a second current phasor measurement at time t. The second current phasor is adjusted so as to account for a determined offset between a first sampling clock associated with the first current phasor measurement and a second sampling clock associated with the second current phasor measurement, thereby resulting in a rotated second current phasor measurement. A residual transient error is then obtained from the rotated second current phasor measurement and the first current phasor measurement.

The invention relates to a half-wavelength transmission line protection method based on transient energy, belonging to the technical field of power system relay protection. If a fault is detected, thevoltage and current abrupt change are calculated by transient electrical quantities detected at the first and last terminals, , through the product of transient voltage and the current abrupt changes, the instantaneous power is calculated, and the transient energy is obtained by integrating the instantaneous power. Based on the polarity of the transient energy, the fault criterion is constructedin and outside the region, no matter where the fault point is located on the line, the method can reliably realize the fault identification in and outside the region. In addition, the polarity of transient energy is not affected by the fault angle and the transient resistance changes. Therefore, the transient energy protection method is suitable for half-wavelength transmission lines.

The invention discloses a single-ended traveling wave ultra-high-speed protection system and method for a flexible direct-current transmission line, and the method comprises the steps: measuring the current and voltage of a protection installation part of a direct-current transmission line, and determining a zero-mode fault current first traveling wave; calibrating the arrival time of the first traveling wave of the zero-mode fault current by utilizing wavelet transform, and starting protection; measuring zero-mode fault current after protection is started, performing reflected wave identification by using wavelet transform, and adaptively changing the length of a data window of protection calculation; constructing a basic fitting function according to the zero-mode fault current first traveling wave expression form, and fitting the obtained zero-mode fault current first traveling wave by using a Levenberg-Marquardt optimization algorithm to obtain a fitting coefficient b; and judgingwhether the obtained b value meets a protection criterion or not to realize protection under different fault conditions. Parameters reflecting fault positions are obtained through fitting, and the method has high-speed mobility, high reliability and high sensitivity.

The invention discloses a line single-phase earth fault relay protection method implemented by the aid of distributed parameters. The line single-phase earth fault relay protection method includes measuring fault-phase voltages, fault-phase currents, fault-phase negative-sequence currents and a zero-sequence current at a power transmission line protection mounting position and using the fault-phase voltages, the fault-phase currents, the fault-phase negative-sequence currents and the zero-sequence current as input variables; computing voltage drop from a single-phase earth fault point to a power transmission line protection setting range position by the aid of a distributed parameter model, computing voltage drop from the power transmission line protection mounting position to the transmission line protection setting range position by the aid of the distributed parameter model, and then judging whether a leading angle between the voltage drop from the power transmission line protection mounting position to the power transmission line protection setting range position and the voltage drop from the single-phase earth fault point to the power transmission line protection setting range position is within the range between -90 degrees and 90 degrees or not. The line single-phase earth fault relay protection method has the advantages that the action performance is unaffected by distributed capacitance currents or transition resistance or load currents, actions can be correctly and reliably performed by the method when a power transmission line single-phase high-impedance earth fault occurs, and the method has high practical value.

The invention provides a method for processing the fault traveling wave of a flexible DC transmission line. The method comprises a step of obtaining the pole mode current and pole mode voltage fault transient traveling wave of the flexible DC transmission line, a step of obtaining a pole mode reverse voltage fault transient traveling wave, a step of obtaining the modulus maximum of the pole mode reverse voltage fault transient traveling wave, and obtaining the equivalent pole mode inverse voltage travelling wave of the pole mode reverse voltage fault transient traveling wave. According to the technical scheme of the invention, the difference between the fault traveling wave and high-frequency transient interference can be effectively displayed, thus the overall characteristic of a flexible DC transmission line fault is more simple and intuitive, the influences of direct current and low frequency signal in the pole mode reverse voltage fault transient traveling wave can be eliminated, the high frequency characteristic of a traveling wave process is highlighted, the analysis difficulty of a flexible DC system downgoing wave process is reduced, and the ultra high speed flexible DC transmission line protection is possible.

The invention relates to a method for protecting a high-voltage DC three-pole power transmission line. The method is used for detecting the ground fault of a DC line and extinguishing fault currents through protection actions. The high-voltage DC three-pole power transmission line comprises a rectifier station, an inverter station, a first pole line, a second pole line and a second pole line, wherein the first pole line, the second pole line and the third pole line are all connected between the rectifier station and the inverter station. The method comprises traveling-wave protection, differential undervoltage protection, line longitudinal differential protection and DC line restarting. The protection of the first pole line, the second pole line and the third pole line is divided into the two steps that (1) the DC voltage variation and the DC voltage variation rate of the first pole line and the second pole line are detected, whether the DC voltage variation and the DC voltage variation rate of the first pole line and the second pole line both meet a setting values or not is judged, and if yes, protecting action is conducted; (2) the DC voltage variation rate of the third pole line is detected, whether the DC voltage rate of the third pole line meets a setting value or not is judged, and if yes, the protection action is protected. Compared with the prior art, the method for protecting the high-voltage DC three-pole power transmission line has the advantage of improving the system safety.

A transmission line protection system comprising at least one signal carrying line buried adjacent the transmission line to be protected, means transmitting a signal through said signal carrying line, and means responsive to damage or severance of said signal carrying line to indicate that said signal carrying line has been damaged or severed and the location of the damage or severance.

The invention discloses a transmission line fault location module, which belongs to the technical field of transmission lines. The transmission line fault location module comprises a data maintenance module, a fault location module, and an operation abstraction module. The operation abstraction module maps transmission line data imported by the data maintenance module to an electronic map to form an electronic map at least including high-speed rails, highways and important transmission channels. The fault location module calculates out the line length from a transmission line fault point to a substation based on transmission line recording data. The operation abstraction module displays the location of the fault point and the environment around the fault point on the electronic map containing the transmission line data according to the calculation result of the fault location module to help a dispatcher to learn about the environment around the fault point quickly and issue a dispatch instruction in time.

The invention discloses a single-phase ground fault type diagnosis method for an ultra-high voltage alternating current transmission line. The method includes the steps: firstly, modeling by a lumped parameter model and calculating a fault distance according to the linear relation between voltage drop and the fault distance from an ultra-high voltage alternating current transmission line protection mounting position to a single-phase ground fault point; secondly, accurately describing physical characteristics of voltage and current transmission of the ultra-high voltage alternating current transmission line by a long line equation and calculating compensation current of the transmission line according to the calculated fault distance; and thirdly, accurately diagnosing single-phase ground fault types of the ultra-high voltage alternating current transmission line according to single-phase ground fault type diagnosis criteria of the ultra-high voltage alternating current transmission line. The method is applicable to single-phase low, medium and high resistance ground fault type diagnosis in the whole fault process of the ultra-high voltage alternating current transmission line, and diagnosis performances are not affected by factors such as transition resistance, load current and system operation modes.

The invention relates to the technical field of electric transmission line protection, in particular to an intelligent bird repellent device for an electric transmission line tower. The intelligent bird repellent device comprises a control module, an intelligent adjustable sound module, a power module and a detection module. The control module is connected with the intelligent adjustable sound module, the power module and the detection module separately; the control module can receive signals detected by the detection module, can analyze and judge whether birds enter the detection range or notand can control the intelligent adjustable sound module to send out a bird repellent sound; the power module supplies electric energy to the whole bird repellent device; the detection module comprises a passive infrared detector and a noise sensor, and the detection module can transmit signals of the passive infrared detector and the noise sensor to the control module; the power consumption of the passive infrared detector and the noise sensor is small, and the monitoring accuracy can be improved by adopting the passive infrared detector and the noise sensor for joint monitoring.

The invention provides a direct-current transmission line protection method and system based on pure current characteristics. The method is characterized in that a current difference value and a current break variable of a line are determined by collecting the current of a direct-current transmission line, and whether a preset protection criterion is established or not is determined according to the current difference value and the current break variable of the line, so that whether the direct-current protection action is outputted or not is determined. The method is advantaged in that the action speed of metallic fault protection can be further increased, the action speed of high-resistance fault protection is greatly improved, protection is reliable and does not act when lightning strokeor abnormal large number occurs, the protection of a non-fault pole line is reliable and does not malfunction under a single-pole grounding fault working condition, and protection performance of thedirect-current transmission line is comprehensively improved.

The invention discloses a direct-current transmission line protection configuration setting method with the electromagnetic coupling relationship taken into consideration. The method comprises the step one of line fault analysis and judgment, the step two of protection starting, the step three of pole logic selection, the step four of disturbance elimination and the step five of boundary determination. According to the method, the situation of possible occurrence of faults of a high-voltage direct-current transmission line is objectively and accurately taken into consideration, influence on normal poles from the faulty poles due to the electromagnetic coupling relationship among polar lines is also taken into consideration, the problem that existing protection is not comprehensive enough is solved, the logic is adjusted without replacing hardware of original line protection, the engineering availability is high, the disturbance-resisting capacity of high-voltage direct-current transmission line protection to false operation possibly occurring due to the electromagnetic coupling relationship is improved, the sensitivity and the effectiveness to the line faults are enhanced, and the unification of the technicality and the economy and the unification of the reliability and the sensitivity of high-voltage direct-current transmission line protection engineering are achieved.

The invention discloses a transmission line anti-contact and anti-external-force warning system which comprises a storage battery, an infrared monitoring module, a logic judging module, a warning loudspeaker and a warning lamp. Whether a foreign object invading the line safety distance exists in the transmission line protection area or not is monitored and judged by transmitting and receiving infrared rays at the high frequency. The installation position and height of the transmission line anti-contact and anti-external-force warning system are set according to the line safety distance, and warning is conducted before the foreign object enters the transmission line protection area. By means of the transmission line anti-contact and anti-external-force warning system, voice and light warning can be given before a large machine such as a crane or a controllable foreign object enters or gets close to the transmission line protection area, the problem that the safety distance of the transmission line is invaded is fundamentally solved, the phenomenon that vehicles and other machines flow frequently or the phenomenon that the contact accident occurs in the constructed transmission line protection area is avoided, the effect of protecting the transmission line against external force is improved, personal safety of personnel and safe and reliable running of the transmission line are better guaranteed.

The invention discloses a method for ranging a single-phase earth fault of a line by using single-end electric quantity. The method comprises the steps of measuring the fault phase voltage, the fault phase negative sequence current, the fault phase current and the zero sequence current in a transmission line protection mounting location; calculating an imaginary part of the ratio between the fault phase voltage and the fault phase negative sequence current; calculating an imaginary part of the ratio between potential drop per unit length of the transmission line and the fault phase negative sequence current; and dividing the imaginary part of the ratio between the fault phase voltage and the fault phase negative sequence current by the imaginary part of the ratio between the potential drop per unit length of the transmission line and the fault phase negative sequence current to obtain the fault distance from the transmission line protection mounting location to the single-phase earth fault point. The method uses the single-end electric quantity to achieve accurate measurement of the single-phase earth fault distance of the transmission line, overcomes the influence of transition resistance and load current on the fault distance measuring accuracy, the ranging principle is simple, the program is easy to achieve, and the method has the advantages of small calculation amount, high ranging speed and high real-time performance.

The invention discloses a direct current transmission line protection method based on mathematical morphological gradient and mathematical morphological entropy, which comprises the following steps: 1) acquiring a direct current line voltage signal and carrying out line-mode conversion on the voltage signal; 2) constructing an improved morphological filter, filtering out noise singular points in aline mode voltage signal, performing multi-scale morphological gradient processing, and constructing a fault starting criterion according to the processing result; 3) carrying out multi-scale mathematical morphological gradient processing on the fault signals, constructing mathematical morphological entropy, a fault criterion of an inner region and an outer region and a fault criterion of an anode and a cathode by utilizing mathematical morphological gradient processing results under different scales. The direct current transmission line protection method based on mathematical morphological gradient and mathematical morphological entropy can quickly filter out the noise singular points in the signal, and quickly and accurately achieve fault identification through multi-scale mathematicalmorphological gradient and morphological entropy.

The invention discloses a line inter-phase fault distance measuring method based on a discrete sampling value. According to the method, effects of inter-phase short circuit fault point voltage instantaneous values on inter-phase fault distance measuring accuracy are considered in an algorithm model, differential discrete processing is performed on differential equations, and fault inter-phase electric quantity sampling values of three adjacent sampling moments are used for calculating fault distances from inter-phase short circuit fault points to electric transmission line protection mounting positions. The method is used for measuring fault distances of inter-phase distance protection, the data amount required to be calculated is small, the calculation speed is fast, the measuring result is not affected by fault positions, transition resistors, system operation modes and load currents, and the measuring accuracy is better than fault distance measuring accuracy of traditional inter-phase distance protection.

The invention discloses a line single-phase earthing fault single-end ranging method realized by utilizing voltage drop imaginary part characteristics. The method utilizes the fault phase negative sequence voltage and the transmission line positive sequence impedance per unit length to calculate the single-phase earthing fault point voltage phase angle, and further calculate an additional fault distance caused by a transition resistance, and the imaginary part of the ratio of the fault phase voltage to the zero sequence compensating current divides the imaginary part of the transmission line positive sequence impedance per unit length and then subtracts the additional fault distance to obtain a fault distance between the transmission line protection mounting part and the single-phase earthing fault point. The method provided by the invention overcomes the impact defects of the transition resistance and load current on single-end fault ranging precision, the ranging precision is high when the transmission line has a single-phase high resistance earthing fault, the ranging principle is simple, the program is easily realized, the fault distance is directly calculated without using a search algorithm, the ranging speed is quick, and the real-time is strong.

The invention relates to a power transmission line phase-to-phase distance protection section III protection method. The method comprises the steps that a fault phase-to-phase voltage, a fault phase-to-phase current and a fault phase-to-phase negative-sequence current at a power transmission line protective installation position are measured firstly, a phase-to-phase arc voltage at a phase-to-phase short-circuit fault point of the power transmission line is calculated, and then the amplitude of the phase-to-phase arc voltage and a rated voltage amplitude of the power transmission line are utilized to form a power transmission line phase-to-phase short-circuit fault relay protection criterion. According to the power transmission line phase-to-phase distance protection section III protection method, lumped parameters are adopted for modeling, the algorithm principle is simple, programs are implemented easily, the calculation amount is small, and protective action is high in speed. By means of the power transmission line phase-to-phase distance protection section III protection method, the power transmission line phase-to-phase short-circuit fault relay protection criterion is formed by utilizing the amplitude characteristics of the phase-to-phase arc voltage, motion performance is not affected by transition resistance and load current, large-area power outage of a power grid caused by great shift of power grid tidal current due to phase-to-phase distance protection III protection false operations under the condition of overload of the power transmission line is effectively prevented, and operation safety and stability of the power grid are reinforced.

The invention discloses a method for adding current traveling wave signal acquisition to a transmission line matching device. On the basis of the software and hardware of a conventional power transmission line support device, the external hardware interface of the device is maintained to be unchanged, a signal amplifying circuit is added to a current transformer secondary side in the device to realize traveling wave signal amplification, and the amplified traveling wave signal is outputted to a newly added traveling wave DSP plug-in through a device backplane to carry out traveling wave signal collection. The full ranges of a traveling wave signal amplification circuit and a traveling wave DSP plug-in collection circuit are designed according to a four-time overload capacity, and a signal which exceeds a full range is subjected to amplitude limiting. The method can be applied to a transmission line matching device of conventional sampling such as a transmission line protection device and a fault recording device, a traveling wave signal acquisition function can be conveniently, reliably and effectively added, and the signal noise ratio and resolution of the traveling wave signal can be effectively improved.

The invention discloses a transfer entropy-based multi-terminal DC transmission line protection method, which comprises the following steps of (S1) collecting positive and negative current of a multi-terminal DC transmission line on a DC circuit breaker of a fault point; (S2) calculating a transfer entropy drop of the positive and negative current; (S3) judging whether a fault appears or not according to the transfer entropy drop and a transfer entropy criterion; (S4) calculating zero-module current on the DC circuit breaker of the fault point by using current decoupling, and carrying out fault judgment according to the zero-module current and a fault pole selection criterion to obtain the fault type; (S5) finding out a fault pole according to the fault type, collecting a current signal ofthe fault pole and calculating a Kurtosis factor; and (S6) judging whether the fault appears in the line or not according to the Kurtosis factor and a Kurtosis factor criterion. According to the transfer entropy-based multi-terminal DC transmission line protection method, the problems of low practicability, a complicated system structure and a poor fault identification effect and the problem thatprotection cannot be carried out in an offline state in the prior art are solved.

The invention discloses a method for realizing line interphase fault single-ended distance measurement by means of real part characteristics of voltage drop. According to the method, a voltage phase angle at an interphase short fault point is calculated by using fault interphase negative sequence voltage and positive sequence impedance of an electric transmission line per unit length, so that an additional fault distance generated due to transition resistance is calculated, and the fault distance from the electric transmission line protection installation position to the interphase short fault point is obtained by subtracting the additional fault distance generated due to transition resistance from the real part of a ratio of the fault interphase voltage to the voltage drop of the electric transmission line per unit length. The method solves the problem that the transition resistance and load current influence the accuracy of single-ended fault distance measurement; and when a high resistance short fault between phases of the electric transmission line happens, the method has high distance measurement accuracy, the distance measurement principle is simple, the procedure is easy to implement, the fault distance can be directly calculated without a search algorithm, the distance measurement speed is high, and the real-time performance is high.