82 results about "Transmission line parameters" patented technology

A multi-sensor data fusion early warning method for monitoring an electric transmission line tower comprises the following steps that 1) current electric transmission line parameters of detection sensors are obtained in real time; 2) first-class BP neural networks are fused; 3) second-class D-S evidence theories are fused, output of the BP neural networks is evaluated between 0 and 1 and processed to be elementary probabilities to serve as evidences of the D-S evidence theories, and danger classes are obtained. According to the second step, 2.1) fault monitoring is carried out on a single detection sensor: a BP network is adopted to construct a detection sensor output sequence predication model, and assuming n time output samples of the observed sensors as x(1), x(2), x(3),..., x (n), (n+1) time sensor output values are predicted; 2.2) the BP neural network of each detection sensor carries out time data fusion; 2.3) input signals are normalized; 2.4) fusion identification is carried out on characteristic layers. The multi-sensor data fusion early warning method is good in stability, high in reliability and good in real-time performance.

The invention provides a power system transmission line parameter synchronic measurement and recording device. An IEC61850 model is uniformly established on a server end according to IEC61850 standard and a fault wave-recording logic model and a transmission line parameter measurement logic module with the same hardware platform are set on the server end and the system configuration is realized according to IEC61850-6 and an independent used configuration tool is formed. The fault wave-recording and transmission line parameter measurements respectively model different logic devices according to IEC61850 standard, namely the data record is realized when the power system is in failure and the synchro measurement of the power system transmission line parameters is realized, thereby solving the problem that the data, parameter read by manpower out-of-step for many times are not accurate in power failure. The accuracy of the line parameter is increased. The power system transmission line parameter synchronic measurement and recording device can be widely used for various application fields such as line wave recording, main-change wave recording, set wave recording, and transmission line parameter synchro measurement.

A system and method for estimating parameters of transmission lines employing phasor measurement units is provided, wherein measurements are provided from the phasor measurement units relating to a transmission line. These measurements are filtered to remove invalid measurements. Using the remaining valid measurements, resistance, reactance and grounding admittance are calculated and estimated and checked for errors.

A system and method for estimating parameters of transmission lines employing phasor measurement units is provided, wherein measurements are provided from the phasor measurement units relating to a transmission line. These measurements are filtered to remove invalid measurements. Using the remaining valid measurements, resistance, reactance and grounding admittance are calculated and estimated and checked for errors.

The invention discloses a line mountain fire disaster assessment method without the real-time acquisition of field information. The method comprises the steps of determining a vegetation type and a vegetation height, judging fire scene fire behavior type, obtaining alarm transmission line information, obtaining meteorological data of a mountain fire position, calculating mountain fire flame zone, ion zone and smoke zone heights, calculating flame zone breakdown voltage, calculating ion zone breakdown voltage, calculating smoke zone breakdown voltage, calculating transmission line trip probability, and evaluating a mountain fire level. The invention also provides a line mountain fire disaster assessment system without the real-time acquisition of field information. The method and the system have the advantages that a bearing body transmission line parameter, a mountain fire internal fire behavior characteristic and external environment conditions are considered, an accurate line fault probability model is established, use data is obtained based on a forestry database and a meteorological data value calculation result, the field acquisition is not needed, the probability quantitative calculation of transmission line trip caused by mountain fire is realized, the adaptability is high, and the mountain fire disaster resistance ability of a grid is improved.

The invention discloses a method for identifying transmission line parameters. The method comprises the following steps: firstly, establishing a linear equation set for describing a transmission line model according to an equivalent model of a transmission line; dividing multiple sets of sampling data of a PMU (Phasor Measuring Unit) within a period of time into multiple data windows in fixed length; specific to the sampling data of each data window, utilizing a least square method to identify the parameters according to the established linear equation set, thereby obtaining an identifying result under each data window; arraying the identifying results under all the data windows in an ascending sort according to the magnitude sequence of the identifying results, thereby obtaining a row of sequencing statistics; and taking a median of the obtained sequencing statistics as a final parameter identifying result. According to the method, the identified parameters are closer to real parameters of the line and are more credible, and the error resistance is ultrahigh.

The invention discloses a parameter adaptive failure distance measurement method for transmission line with four-circuit on a single tower. The method comprises the following steps: 1) respectively measuring voltage and current power frequency phasor of each circuit at each phase of the two ends of the transmission line in normal status and failure status; 2) obtaining four-circuit decoupling transformation matrix of the transmission line with four-circuit on the single tower, and carrying out decoupling transformation for the voltage and current power frequency phasor of each circuit at each phase of the two ends of the transmission line in normal status and failure status to obtain voltage and current power frequency phasor of four-modulus at each sequence of the two ends of the transmission line in normal status and failure status; 3) establishing an adaptive equation of positive sequence transmission parameters and characteristic resistance line parameters for the transmission line to obtain a positive sequence transmission parameter and characteristic resistance; and 4) establishing an distance measurement equation for transmission line with four-circuit on the single tower based on circular current modulus to obtain the failure distance. The invention is not affected by uncertainty of transmission line parameters, and has the advantages of easy implementation, high stability and high precision.

The invention relates to an online identification system of a transmission line parameter and an identification method thereof. The technical characteristics are that the online identification system includes a data receiving module, a steady state data processing module and a parameter identification module which are connected in sequence; the data receiving module is for receiving PMU measured data issued by a provincial WAMS system front-end processor in real time, and screening out transmission line telemetry data to be identified; the steady state data processing module is for steady state processing of the transmission line telemetry data output by the data receiving module to remove telemetry bad data and transient state data and generate steady data of a 5-minute section; and the parameter identification module is for accurately identifying and calculating a transmission line parameter using the PMU measured data after steady state processing, taking a result obtained by accurate identification and calculation as a final transmission line steady state identification parameter, and verifying the precision of the transmission line online identification parameter. According to the invention, the parameter of the transmission line operation can be accurately identified, and the identification precision and practicability are high.

Embodiments relate to enhancing echo cancellation in a transceiver integrated circuit (IC) for full-duplex communication by providing a signal path connected to a dummy driver that replicates a signal path between a main driver and a counterpart transceiver IC to cause a duplicated signal generated by the dummy driver to more closely replicate a sending signal generated by the main driver. The signal path connected to the dummy driver includes circuit elements having transmission line parameters and RLC parameters that replicate transmission line parameters and RLC parameters of circuit elements in the signal path between the main driver and the counterpart transceiver IC.

The invention discloses an on-line monitoring system for an electric power transmission line. The on-line monitoring system is characterized by comprising a monitoring center and a plurality of monitoring sites, and each monitoring site comprises a transmission line parameter collecting unit, a signal processing unit, an A / D converting unit and a control unit, wherein the signal processing unit is connected with the transmission line parameter collecting unit and used for filtering and amplifying collected transmission line parameters, the A / D converting unit is connected with the signal processing unit and used for carrying out analog-digital conversion on an output signal of the signal processing unit, and the control unit is connected with the A / D converting unit and used for judging the transmission line fault according to a transmitted transmission line parameter digital signal, determining the corresponding fault position and feeding the transmission line parameters and a judgment determining result back to the monitoring center in real time. According to the on-line monitoring system for the electric power transmission line, operation states and the parameters of the transmission line are monitored in real time on line, the fault can be rapidly and conveniently judged, the fault position can be rapidly and conveniently determined, the reliability, the safety and the stability of the operation of an electric power system are guaranteed, and the efficiency and processing speed are high.

The invention discloses a power grid fault diagnosis and transmission line parameter identification system which comprises a fault characteristic analysis module, a fault intelligent diagnosis module,a power grid fault deduction module, a line parameter identification module, a protection information management main station FIS application and a visual man-machine interface. The input ends of thefault characteristic analysis module, the fault intelligent diagnosis module, the power grid fault deduction module and the line parameter identification module are connected with the protection information management main station FIS application, and the output ends of the fault characteristic analysis module, the fault intelligent diagnosis module, the power grid fault deduction module and theline parameter identification module are connected with the visual man-machine interface. According to the power grid fault diagnosis and transmission line parameter identification system, auxiliary tools and convenient means for power grid professional management and operation personnel to fast locate power grid fault problems and transmission line parameter checking are provided.

The invention discloses a same-tower double-loop AC power transmission line parameter measuring and calculating method. The method comprises the following steps: dividing a same-tower double-loop power transmission line into three wiring modes; measuring open-circuit impedance and short-circuit impedance under the condition of each wiring mode; by use of measuring results of the open-circuit impedance and the short-circuit impedance under the condition of each wiring mode, calculating characteristic impedance and a propagation coefficient under each corresponding wiring mode, and further calculating distribution impedance and distribution admittance under the corresponding mode; and finally, through the distribution impedance and the distribution admittance under each wiring mode, establishing a system of simultaneous equations, and calculating resistance, inductance and grounding capacitance of each lead wire of the same-tower double-loop line, alternate coupling capacitance and alternate coupling inductance of a single-loop line and coupling capacitance and coupling inductance between each lead wire of a double-loop line. According to the invention, error factors are avoided, various parameters of the same-tower double-loop power line at the frequency of omega can be accurately obtained, a reliable and accurate data source is provided for various calculation of a power system, and the calculation result is enabled to be more accurate.

The invention discloses an electronic tester for power frequency parameters of a same-tower multi-loop electric transmission line and a testing method of the electronic tester for the power frequency parameters of the same-tower multi-loop electric transmission line. The electronic tester comprises a synchronous power source, a testing power source and an electric transmission line parameter testing device. The electric transmission line parameter testing device comprises an upper computer, a lower computer, a control switch and a data collecting module, wherein the synchronous power source is directly connected with the data collecting module, the testing power source is connected with the data collecting module through the control switch, the upper computer is connected with the control switch through the lower computer, the lower computer is connected with the data collecting module, and the data collecting module is connected with lines to be tested. By means of the electronic tester and the testing method, the testing accuracy and the testing efficiency can be improved. The electronic tester for the power frequency parameters of the same-tower multi-loop electric transmission line is small in size, light in weight and convenient to transport and use. The testing method of the electronic tester for the power frequency parameters of the same-tower multi-loop electric transmission line is convenient and practical.

Embodiments of the invention provide a phase shift unit, a phase shifter and a base station antenna. The phase shift unit comprises a sliding medium and multiple segment strip lines; each of the striplines comprises a main transmission line and multiple loading portions disposed on the main transmission line; connection is established between each of the strip lines by the main transmission line;at least one of main transmission line parameters and / or loading portion parameters of the each two segments adjacent strip lines is different from each other; and the sliding medium is used for changing a coverage state on the multiple segment strip lines by sliding, thereby achieving phase shift. Through arrangement of the multiple segment strip lines, the phase shift unit, the phase shifter and the base station antenna provided by the embodiments of the invention make the sliding medium change the coverage state on the multiple segment strip lines in a sliding process, and therefore, underthe premise of not increasing the size of the phase shift unit, a phase shifting section and a matching section are combined into one, the phase shifting amount is improved, a matching series is reduced, the matching effect is improved, and the problem that the phase shifting amount of an electrically adjustable base station antenna has a large demand is solved.

The invention discloses a method for monitoring the synchronous state of a line protection pilot channel. The method comprises the steps of: step 100: collecting transmission line parameters and electric quantities on the two sides and then performing the step 200; step 200, calculating a relationship curve between the theoretical value of the included angle of the two sides and the theoretical value of the current of the own side according to the line equivalent model by using the collected line parameters and the electric quantities of the two sides, and then executing step 300; step 300, obtaining the theoretical value of the included angle of the two sides current and the theoretical value of the included angle of the two sides voltage according to the calculation result in the step 200 and the electric quantity of the two sides collected in the step 100, and then executing the step 400; step 400, according to the calculation result of step 300 and the electric quantities on both sides collected in step 100, determining the synchronization state of the line protection pilot channel by error analysis. At the same time, the invention discloses a corresponding apparatus for monitoring the synchronous state of a line protection pilot channel. This method does not depend on GPS pairs and is not affected by load current.

The invention belongs to the electromagnetic compatibility transmission line unit length electrical parameter analysis field, and more specifically relates to a heterogeneous multiple conductor transmission line inductance matrix direct evaluation method. The method comprise: first employing fine line grids to disperse each signal line conductor and a grounding plate into fine line structures, wherein the current fine line of each signal line conductor forms a loop with the sth fine line of the grounding plate to obtain Nc loops; meanwhile calculating a directional factor referring to transmission line parameter analysis; writing equations in a matrix form; and obtaining a heterogeneous multiple conductor transmission line impedance matrix. The method can obtain accurate measurement results, have a more convenient calculation process than a traditional method, directly solve an inductance matrix without multitime conversion, and possess high practical reference value.

The invention provides a simulation calculation method of induced voltage and current of a newly-built HVDC transmission line based on PSCAD. Through building of a PSCAD simulation model, the transmission line relevant parameters in PSCAD software are set according to of obtained transmission line parameters , ground parameters, transmission tower parameters and parameters of soil resistivity along the transmission line, a DC model of the transmission line and a model of the new DC circuit are established, and three-phase voltage source models are established at both ends of the live transmission line to simulate and calculate the electrostatic induction voltage, electrostatic induction current, electromagnetic induction voltage and electromagnetic induction current of the new HVDC transmission line. The method can accurately evaluate the induced voltage and induced current on the construction line, timely take the safety measures, and improve the safety operation ability of the transmission line staff.

There is described a method of determining power transmission line parameters using non-synchronous measurements acquired from different locations along a power transmission line. The method comprises (a) acquiring first measurement data comprising corresponding pairs of voltage and current measurement values measured at a first location along the power transmission line at predetermined points in time relative to a first time reference, (b) acquiring second measurement data comprising corresponding pairs of voltage and current measurement values measured at a second location along the power transmission line at predetermined points in time relative to a second time reference, (c) calculating initial values of the power transmission line parameters and an initial value of the difference between the first time reference and the second time reference based on the first measurement data and the second measurement data, and (d) calculating resulting values of the power transmission line parameters and a resulting value of the difference between the first time reference and the second time reference by utilizing a least squares algorithm and the initial values of the power transmission line parameters, the initial value of the difference between the first time reference and the second time reference, the first measurement data, and the second measurement data. Furthermore, a data acquisition device and a system for determining power transmission line parameters as well as a computer program and a data carrier are described.

The invention discloses a stranded wire RLCG parameter extraction method based on a BAS-BP algorithm. According to the stranded wire RLCG parameter extraction method, a novel stranded wire RLCG parameter extraction network model is established based on a beetle antennae search algorithm (BAS) and a BP neural network algorithm. The stranded wire RLCG parameter extraction method can utilize the network to extract a high-precision RLCG electromagnetic parameter matrix at any position of a stranded wire, and comprises the following steps of: firstly, establishing a stranded wire model and extracting a parameter sample by virtue of an ANSYSQ3D software platform; carrying out sample processing after a space structure of the stranded wire is analyzed; importing the processed data into a BAS-BP neural network model; and finally, acquiring an optimal extraction network through training and testing. The existing transmission line RLCG parameter extraction methods are mostly based on a numericalalgorithm, lack of processing capacity for stranded wire type non-uniform transmission lines, is based on the intelligent algorithms, has the advantages of high precision, high efficiency and the likecompared with a traditional method, has no special requirements for wire types, and can better solve the problem of extraction of stranded wire electromagnetic parameters.

A method for calculating efficiency of a power supply system includes: displaying a parameter selection interface on the display unit for selecting power supply parameters and transmission line parameters. Obtaining power supply parameters and transmission line parameters selected by the user via the parameter selection interface when determining the user has finished the selection. Determining a efficiency of a selected power supply of the power supply parameters according to the relationship table, and calculating a sum efficiency according to the obtained power supply parameters and the transmission line parameters and the efficiency of the selected power supply. And calculating a total efficiency of the power supply system according to each sum efficiency when determining that all of the power supplies of the power supply system have been selected.

The invention discloses an online calibration method and device for a synchronous phasor measurement unit. The online calibration method comprises the steps of measuring the synchronous phasor measurement unit under different load conditions to acquire multiple groups of synchronous phasor measurement unit data, and calculating multiple groups of transmission line parameters according to the multiple groups of synchronous phasor measurement unit data; solving a partial derivative of each measurement value according to the multiple groups of synchronous phasor measurement unit data, and generating an impedance partial derivative parameter; acquiring static parameters of a transmission line from an energy management system so as to determine a search space, performing clustering on partial derivatives of the line parameters in the search space, and generating a parameter error together with the multiple groups of transmission line parameters; determining a system error according to the impedance partial derivative parameter and the parameter error, and performing calibration on the synchronous phasor measurement unit according to the system error. According to the invention, an enough accurate parameter error can be generated according to an energy management system mathematical model and the static parameters, and the model based calibration method is enabled to have practical application values.

The invention discloses a rapid detection method of a tail current of a current transformer so that a technical problem of increasing the detection speed of the tail current of the current transformer is solved. The method comprises: acquiring a transmission line parameter; calculating an impedance angle and a decay time constant of a secondary loop; collecting a parameter of a transmission line power voltage before a fault moment; calculating an effective value of a fault current fundamental wave; and comparing the effective value of the fault current fundamental wave with a constant current value of failure protection. Compared with the prior art, the rapid detection method has the following beneficial effects: two-time differential filtering is carried out, the effective value of the fundamental component in the tail current is obtained by means of quarter-cycle absolute value integration, and the effective value is compared with a constant current return value of failure protection to determine whether the effective value is lower than the constant current return value, and the normal operation state is recovered when the fault state is eliminated or the protection action condition is not met, so that the tail current determination time is reduced to be within 10ms, the failure protection action delay is reduced while high reliability is ensured, and the operation risk of the power system is reduced.

A system and method for analyzing a circuit with transmission lines includes determining which sources influence each of a plurality of transmission lines, based on coupling factors. Transmission line parameters are computed based on the sources, which influence each transmission line. A transient response or frequency response is analyzed for each transmission line by segmenting each line to perform an analysis on that line. The step of analyzing is repeated using waveforms determined in a previous iteration until convergence to a resultant waveform has occurred.

The invention relates to a high robustness electric transmission line parameter estimating method based on a multi-time period PMU, which belongs to the power system scheduling automation field. In this method, a parameter estimating model constituted of an objective function and constraint conditions is established; the objective function is the smallest among residual error weighted sum squares in N time periods; based on the KKT complementary slack condition corresponding to the parameter estimating model, the parameter estimating model is solved to acquire an optimum solution X; the time periods are arranged in descending order according to the maximum residual error of each of the time period; the time period of the optimum residual error is recorded as k; if the maximum residual error in the time period is smaller than a measuring residual error threshold, the parameter estimation is finished; and the acquired optimum solution is used as the estimation result of the parameter. According to the invention, the analytical form of the optimum solution of the model is solved based on the KKT condition, thus the calculating efficiency is ensured to be high; through the exclusion of the damaged datum and the iterative process of the parameter estimation, the damaged datum are eliminated effectively, thus improving the accuracy of the parameter estimation and ensuring the practicality of the method.

A system and method for analyzing a circuit with transmission lines includes determining which sources influence each of a plurality of transmission lines, based on coupling factors. Transmission line parameters are computed based on the sources, which influence each transmission line. A transient response or frequency response is analyzed for each transmission line by segmenting each line to perform an analysis on that line. The step of analyzing is repeated using waveforms determined in a previous iteration until convergence to a resultant waveform has occurred.

The invention discloses a method for estimating the parameters of an incompletely commutated three-phase power transmission line based on PMU measurement, including the estimation of 12 admittance parameters and the estimation of 12 impedance parameters. The beneficial effects are as follows: the method for estimating the parameters of an incompletely commutated three-phase power transmission linebased on PMU measurement overcomes the shortcomings of the previous parameter estimation methods; the estimation errors of self-impedance and self-admittance parameters are less than 1%, and the estimation errors of mutual-impedance and mutual-admittance parameters are less than 2%; and more accurate power transmission line parameters can be provided for an energy management system, so that the error parameters of an incompletely commutated three-phase power transmission line can be identified accurately and calibrated in time and online.

The invention discloses an improved Monte Carlo method for solving a section DC load flow model, and the method comprises the following steps: 1), establishing the section DC load flow model; 2), generating random variables in the sections of a corresponding load, generator active output and transmission line parameters through employing a stochastic simulation technique, wherein the random variables are called as scenes; 3), adding an extreme scene on the basis of the scenes generated at step 2), wherein the extreme scene indicates the upper and lower boundaries of the parameter section; 4),carrying out the statistical operation of the maximum and minimum values of the load flow variables in all scenes; 5) outputting a result which comprises a section calculation result of a phase angleand transmission power. The method provided by the invention employs the stochastic simulation technique for generating a series of scenes in the section of input data, and obtains the load flow section through the statistical operation of the maximum and minimum values of the load flow variables in the generated scenes. Moreover, the method further improves the precision of a section DC load flowmodel solution through the consideration to the extreme scene of the input data.

The invention relates to a parameter determination method of a power distribution device, the power distribution device and a device. The method comprises the steps of obtaining the working frequencyof a power distribution device and the power division ratio range of the output end of the power distribution device; determining reference power frequency information according to the working frequency and the power division ratio range, wherein the reference power frequency information is used for indicating the linear relation between the power division ratio of the output end of the power distribution device and the working frequency; calling a simulation model corresponding to the power distribution device; adjusting the transmission line parameters of the simulation model, and obtainingthe real-time power frequency information outputted by the simulation model; and when the real-time power frequency information is matched with the reference power frequency information, outputting atransmission line parameter corresponding to the real-time power frequency information. The power distribution device composed of transmission lines produced on the basis of the obtained transmissionline parameters effectively improves the beam forming of the broadband antenna.

Methods and apparatus are provided for predicting the number of iterations needed for a computed Transversal Waveform Relaxation solution to achieve a given level of accuracy. In this manner, a Transversal Waveform Relaxation algorithm is disclosed that provides full automation. According to one aspect of the invention, a circuit is analyzed having transmission lines. One or more transmission line parameters of the circuit are obtained, as well as the intrinsic behavior, E(ω), and strength of coupling, N(ω), of each of the transmission lines. In addition, a relative error bound is obtained for the circuit based on the intrinsic behavior, E(ω), and strength of coupling, N(ω), of the transmission lines and a predefined error threshold. The process then iterates until the relative error bound satisfies the error threshold.