119 results about "GOT measurement" patented technology

The invention relates to high-precision in-situ detection for complicated curved-surface parts with high-curvature surface form. In order to provide non-contact for the parts and detection for the surfaces of the parts, the invention provides the following technical scheme, namely a high-precision non-contact measurement method and a high-precision non-contact measurement device for a three-dimensional profile of an optical freeform curved surface. A grating projection device is used for projecting a sine grating stripe onto the surface of a measured object; an image acquisition device acquires a deformed stripe pattern modulated by the surface of the measured object and sends the deformed stripe pattern into a computer to recover the three-dimensional profile of the surface of the measured object; a white light scanning interference measuring head is used for scanning and measuring local characteristics of the measured object in nano-scale precision; a white light scanning image acquisition device acquires an interfered stripe pattern and sends the interfered stripe pattern into the computer to acquire data of the three-dimensional profile of a measurement region; and a result can be obtained according to data obtained by measurement of a grating projection vision detection unit and a white light scanning interference measurement unit through a multi-sensor massive data combination algorithm and corresponding error separation and compensation measures. The invention is mainly applied to the high-precision in-situ detection of the parts.

The invention discloses a method for calibrating a spatial coordinate measuring system of an electronic theodolite, which aims to meet the need that the measuring system of the electronic theodolite calibrates in the range of tens of meters in any direction at an angle of horizontal 360 DEG and pitching + / -45 DEG. The method comprises the following steps of: placing instruments and targets; 2, using a laser radar scanner to assign a value to the targets to form a standard instrument group; step 3, the calibrated system of the electronic theodolite measures each target to obtain measured values; step 4, converting the measured values of the electronic theodolite to a measurement coordinate system of the laser radar scanner; and step 5, comparing the converted measured values of the electronic theodolite with a standard value thereof, and obtaining the measurement deviation and measurement uncertainty evaluation of the measuring system of the electronic theodolite through software analysis. The method meets the need that the measuring system of the electronic theodolite calibrates in the range of tens of meters in any direction at the angle of horizontal 360 DEG and pitching + / -45 DEG.

The invention relates to a digitizing detection method of a complicated curved face. The method comprises the following steps: (1) extracting the geometric data of a CAD model of the complicated curved face, establishing an NURBS theoretical model of the complicated curved face, measuring a part object with the curved face by a three-coordinate measuring machine, digitizing the surface of the partto obtain the parameter of a measuring point; (2) establishing a binary nonlinear mathematical model with the minimum distance from the measuring point to an isoparametric line areas of the curved face by searching two groups of isoparametric line areas with isoparametric line structure proximate to the measuring point on the CAD curved face; and (3) calculating the shape error of the complicatedcurved face by a genetic algorithm to realize the error estimation of the complicated curved face. Compared with the prior art, the invention establishes an accurate curved face theoretical model, enhances the searching efficiency, can ensure the acquisition of a globally optimal solution and lightens the measuring intensity.

The invention relates to system and method for detecting the transformer winding state by using constant-current sweep frequency power source excitation. A measurement and control analysis module controls sweep frequency power source and applies output constant-current sweep frequency excitation signals by an exciting transformer at a high-voltage side of the transformer to be detected; a vibration sensor measures vibration response signals of a transformer winding to be detected at different excitation frequencies; a vibration signal collector collects and preprocesses the signals measured by the vibration sensor; and the measurement and control analysis nodule carries out spectrum analysis to the received and processed vibration response signal data, displays and records a resonant frequency curve of the transformer winding on a frequency domain, compares with the resonant frequency curve previously measured and recorded as well as the vibration frequency curve of a transformer three-phase coil, and judges the state of the transformer winding to obtain the measuring result. The invention can effectively and sensitively detect the states of looseness or deformation of the transformer winding for prompt repair or replacement so as to avoid a fault of abrupt short circuit of the transformer caused by damage of the winding structure.

The invention discloses a bidirectional magnetic saturated time difference fluxgate sensor, which is characterized in that two ends of a sensor magnetic core are wound with exciting coils, the middle section of the sensor magnetic core is wound with induction coils, output poles of the induction coils are connected with an amplifying circuit, and the amplifying circuit is connected with a counting display circuit through a band-pass filter circuit and a retardation shaping circuit. By detecting and calculating a positive negative pulse time difference value output by the fluxgate sensor in a time domain, the strength of the measured magnetic field is judged. Compared with the prior fluxgate sensor, the detection circuit is simple, the measurement stability of the system is ensured without a feedback structure, a complex subsequent circuit is not needed, the required excitation current is lower, the data processing is simple, the measured relative quantity is little, the integral volume and power consumption of the sensor are effectively reduced, and the measurement result is acquired quickly. The fluxgate sensor avoids a filter-phase-sensitive demodulation-smooth filter circuit of the prior fluxgate sensor, makes up the defect that the prior fluxgate sensor has harsh process requirement, and achieves the digitized magnetic measurement of the fluxgate sensor.

An excitation method of a vibrating wire sensor mainly comprises the following operating steps: performing single excitation for exciting coils of the vibrating wire sensor by an intermittent excitation mode to obtain a resonant frequency measured value f1 with low precision; calculating statistical characteristics of vibration signals during various periods, and inspecting the statistical characteristics; exciting the exciting coils of the vibrating wire sensor by adopting a signal with the frequency being f1 and stopping excitation after vibrating wire resonance, or performing frequency-sweep excitation at the position of a narrower bandwidth near the frequency f1; and finally processing signals from vibration pickup coils, and measuring the signal frequency to obtain a measured value f2 as an exact value of vibrating wire resonance frequency. The excitation method of the vibrating wire sensor has the advantages of fast starting of vibration, large amplitude, shortened detection time, improved working efficiency, improved excitation reliability and improved measuring precision. The excitation method of the vibrating wire sensor is applicable to observation on stress strain, deformation, seepage, liquid level, temperature and the like of the projects such as reservoir dams, bridges, foundation pits and the like.

The invention discloses a digital calibration system of partial discharge test equipment. The digital calibration system is characterized in that the system comprises a device to be tested, and a digital calibrator and a measurement and control computer of the partial discharge test equipment which is connected with the device to be tested, wherein the output end of the digital calibrator of the partial discharge test equipment is connected with the measurement and control computer; the measurement and control computer compares the collected waveform and data measured value with the standard value output by the digital calibrator to perform analysis and calculation and obtain the error of the measured value and the standard value, outputs the error value, and measured value and standard value to a data outputting machine so as to realize the calibration of the partial discharge test equipment. In the system of the invention, the wide measuring range which is 1-10000pc, the high accuracy standard pulse calibrator and a high speed data acquisition card with 12 bits of precision are adopted to ensure the calibration accuracy to reach + / -2%.

The method gets the periodic signal and compound signal of encoder through processing the pulse signal, reset signal from encoder and measurement period signal given by measuring man. By using the formula raised by the invention, the MPU can figure out the rotate speed of motor and the position of rotor. The invention can also remove the measuring error for motor caused by radial and axial vibration.

The invention discloses a real-time precision monitoring method of millimeter crustal displacement, and relates to the seismic survey technology, wherein, the method comprises the following steps: 1) emission points are arranged in a large region grid manner, and a microminiature satellite survey terminal is arranged on nodes of a monitoring network; 2) a national ground information processing central station is divided into a center and a regional center; 3) information acquired by the microminiature satellite survey terminal is transmitted to a synchronous communication satellite, then forwarded to a downlink by a satellite repeater, and received by a large antenna in the ground information processing central station, and the data are acquired and processed in a centralized manner; 4) crustal shock parameters of a position at which the survey terminal is positioned are obtained, in which the survey resolution of the displacement and the amplitude are not greater than 1mm, the survey frequency is not greater than 50HZ, and the survey period is not greater than 20ms; and 5) terminal monitoring points are operated in an unmanned manner. The method can help continuously and exactly monitor the movement and variation of the crust in a real time, provides information for predicting and forecasting earthquakes, and can help survey the shock and the displacement of dams, bridges, high-rise buildings, large facilities and the like.

A method for segmenting the data of a 3D sensor produced in the presence of aerosol clouds and for increasing the situation awareness and the location detection of obstacles involves transforming the sensor data are transformed into a 3D measurement point cloud, determining related subsets as measurement point clusters from the 3D measurement point cloud of an single measurement cycle of the 3D sensor based on the local measurement point density, determining at least one of the characteristic parameters of the individual measurement point clusters, the characteristic parameters including position, orientation in space, and shape, and determining a time variation of the characteristic parameters using the recorded parameters calculated from subsequent measurement cycles, from which the association of a measurement point cluster with a real obstacle or with the aerosol cloud results.

The invention provides a method for calibrating the saturation of a closed coring well, comprising: step 1, based on the analysis data of the surface porosity Φs and the overburden porosity Φr measured by the core samples of the closed coring well, establishing the cause of the saturation caused by the change of the rock pores and oil-water volume The correction formula for the change of oil content and water saturation of the measured sample; step 2, establish the formula for the change of oil content and water saturation loss of the measured sample caused by degassing and draining; The mathematical correction model of saturation loss due to the change of pore volume and oil-water volume and fluid saturation loss caused by depressurization and degassing and drainage can obtain the real oil and water saturation of the underground before measuring the saturation loss of core samples. The correction method for measuring oil and water saturation of core samples from closed coring wells realizes the accurate calculation of oil and water saturation of oil layers under formation conditions, and provides important basic parameters for reservoir engineering optimization research.

The invention provides a cable conductor temperature indirect measurement method. A measurement point E is selected on the external sheath of a cable, and the cable is electrified and then the temperature value of the point E is acquired by using a temperature sensor so that a temperature measurement value set Tm(t) of the measurement point is obtained; a cable temperature field finite element model is established and analytical calculation is performed on a cable temperature field so that the temperature calculation value TE of the point E is obtained; the error between the actual temperature measurement value Tm(t) of the point E and the calculation value TE is processed so that the initial thermal parameters of the temperature field model are corrected; and the corrected thermal parameters substitute the original initial thermal parameters to be loaded into the finite element thermal model so that a corresponding relation table between surface temperature and conductor temperature is acquired, and conductor temperature is obtained by using a table loop-up mode after measuring surface temperature. The thermal parameters of the internal material of the cable are identified so that the temperature field model of the cable is corrected. The correct corresponding relation between surface temperature and conductor temperature is obtained on the basis of the corrected temperature field model so that conductor temperature is indirectly obtained through measurement of surface temperature.

The invention discloses a steady filtering method based on robust estimation, belonging to the technical field of data processing. The method comprises the following steps of: acquiring measurement data of a motion carrier by using an inertia sensor; carrying out robust estimation on measurement data to acquire a robust estimation value of the measurement data; respectively carrying out INS (Information Network System) solution and DR (Data Recorder) solution on the robust estimation value of the measurement data to acquire INS navigation information and DR navigation information of the motion carrier; carrying out steady Kalman filtering on the INS navigation information and the DR navigation information of the motion carrier to acquire INS / DR navigation fault information of the motion carrier. By introducing the robust estimation into a combined navigation method, the combined navigation system has better robust performance; and the steady Kalman filtering weakens the influence on a filtering result by uncertainty of a system model, thereby the method improves the robustness of the system, and has the wide application prospect in the fields of the information fusion and combined navigation system.

The invention discloses a spatial circular attitude identification ambiguity elimination method based on angle constraint. The method comprises the following contents: an inner parameter of the camera is obtained by calibration; the measuring image is obtained by taking a photo for spatial circular through the camera; the elliptical edge points and the characteristic points of geometrical elements in the measuring image is treated; the center coordinate of the spatial circular under the camera coordinate system and the normal vector of the plain on which the spatial circular is arranged are calculated.; furthermore, the formula of the spatial geometrical elements which is corresponding to the geometrical elements on the measuring image can be obtained; based on the spatial geometrical elements formula and the known spatial angel constraint, the true normal vector of the plain can be determined. By introducing the coplanar geometrical elements on the spatial circular plain and based on the angle constraint, the method effectively eliminates the ambiguity in the spatial circular attitude identification, and improves the practicability and reliability of the spatial circular attitude identification.

The invention provides a detection method for a train bearing fault. The method comprises the following steps of: comprehensively detecting an integral fault characteristic spectrum so as to ensure the safety of a train bearing; and when detection signals are implemented, performing further processing by utilizing related methods after a measured spectrum result is obtained by sampling, conversion and calculation so as to overcome the interference of random vibratory impulses in measurement. The method has the effects that a KW2002 bearing fault diagnostic apparatus designed and manufactured by utilizing the method is used for realizing the static no-disassembly detection of faults comprising the abrasion of a bearing component, and a KW0021 train bearing monitor designed and manufactured by utilizing the method can be used for monitoring the status of the bearing in real time in the running of a train to realize the early warning of the bearing fault, so that the safety of railway traffic is greatly improved; and minor fault characteristics can be detected in the running of the train, and the long-lasting thinking mode that the inference produced in the running of the train cannot be overcome in China is broken.

The invention relates to a rapid detection tool for a large taper hole. The detection tool comprises a detection tool pedestal, wherein the detection tool pedestal is provided with an adjusting arm and a measuring arm which are vertically distributed; the measuring arm is provided with dial indicators for measuring angular error of the taper hole; and the adjusting arm is provided with adjusting screws for demodulating the dial indicators. In the detection tool, an instrument support is provided with the measuring arm; an adjusting support is provided with the adjusting arm; the adjusting arm is provided with a first adjusting screw and a second adjusting screw; the measuring arm is provided with a first detection dial indicator and a second detection dial indicator; the first detection dial indicator and the second detection dial indicator perform zero reset through the first adjusting screw and the second adjusting screw; the aperture and the taper of the large taper hole can be rapidly measured according to tape error values of the first detection dial indicator and the second detection dial indicator in comparison with the standard taper of a standard taper ring gauge; the detection is convenient and fast, and the working efficiency is greatly improved; and the detection tool has a wide application range, no sliding friction, long life and a simple structure and is lower in manufacturing cost.

The invention discloses a unified service quality measurement system and a unified service quality measurement method, wherein the system comprises a service quality measurement server, an information database and service quality measurement proxies. The method comprises the following steps: the service quality measurement server, according to a received measurement request and information of the service quality measurement proxies and network information which are stored in advance, selects one service quality measurement proxy and a service quality measurement method which are used for the measurement, and notifies the selected service quality measurement proxy the service quality measurement method; the selected service quality measurement proxy performs corresponding measurement operation according to the service quality measurement method, and reports measurement data to the service quality measurement server; and the measurement data reported by the service quality measurement proxy is statisticized and analyzed to obtain a measurement result. The unified service quality measurement system and the unified service quality measurement method solve the problem that the service quality measurement is dispersed inside various services further to provide a supplementary means for network optimization as well as fault and bottleneck positioning.

This invention relates to one supersonic wave measurement distance method and device, which comprises the following steps: sending measurement signals; receiving echo wave signals; echo signal filter amplifying processing; storing the A / D conversion and its results on echo signals; comparing the test wave signal and peak value signals; according to comparison results stopping A / d samples; analyzing stored A / d conversion result data and finding echo oscillator point; according to conversion speed to compute echo time to get measurement distance.

The invention designs a laser absorption spectrum tomography system for axisymmetric combustion field monitoring. Elements include a laser light source, a scanning galvanometer, an optical fiber bundle, an integrating sphere, a photoelectric detector, a data acquisition module and the like, wherein the laser light source is irradiated on the scanning galvanometer, passes through a measured combustion field after being reflected by the scanning galvanometer, and is irradiated onto the optical fiber bundle; the integrating sphere is placed at an outlet of the optical fiber bundle; the photoelectric detector is placed at an outlet of the integrating sphere to receive a signal; the data acquisition module is used for acquiring spectral absorption data after laser light passes through the measured combustion field; and temperature distribution and concentration distribution of the combustion field in a measurement area are obtained through resolving. The system is simple in structure and convenient to operate, and has relatively high useful values and wide application prospects in the field of combustion diagnosis.

This invention discloses a method for detection and analysis of impurity content of refined metallurgical silicon, comprising: (1) select the measuring points on the crystal rods or crystal ingots along the crystallization direction, measuring the resistivity at each measuring point and acquire the measured value of resistivity according to the distribution of crystallized fraction; (2) get the estimated value of the content of boron and phosphorus at each measuring point and calculate the estimated net redundant carrier concentration and the measured value of resistivity; (3) compare the estimated value of net redundant carrier concentration with that of the measured value, and adjust the estimated value of impurity content in the silicon material to get the new estimated net redundant carrier concentration, and use regression analysis to determine the impurity content distribution of boron and phosphorus; (4) get the average impurity content of boron and phosphorus in the silicon material according to the distribution status of impurity based on all the measuring points. This invention can detect accurately the impurity contents of boron and phosphorus in refined metallurgical silicon, while the operation is simple, low-cost and suitable for industrial applications.

The invention provides a three-sided five-wire machine tool space geometry error measurement and identification method based on plane grating. The method is characterized by designing and planning measurement paths in a measurement range of the plane grating in three measurement planes of XOY, XOZ and YOZ respectively; then, carrying out identification on each error in the planes of XOY, XOZ and YOZ in sequence: to begin with, carrying out identification to obtain a perpendicularity error between two axle in one measurement plane, carrying out identification based on relationship between different trajectories to obtain pitching and deflection angle errors after eliminating the influence of the perpendicularity error, carrying out identification to obtain positioning errors and straightness errors after eliminating the influence of the angle errors, and finally, substituting the obtained errors obtained through identification of the three planes to models and carrying out identification to obtain roll angle errors; and carrying out parameterized modeling on each geometric error term, obtaining an error curve of each geometric error through an orthogonal polynomial fitting method, and finally, realizing a full identification process of the space geometry errors. The method can meet space geometry error identification requirements, and has the advantages of high measurement efficiency and high measurement precision.

The invention provides a terminal with function of a multimeter, which comprises: a positive meter pen interface, a negative meter pen interface, a first selecting switch, a front-end acquisition circurit, a multichannel simulation control circuit, an analog-to-digital converter, and a processor, wherein the positive meter pen interface is used for connecting a positive meter pen; the negative meter pen interface is used for connecting a negative meter pen; the first selecting switch is used for selecting the meter pen interface so as to be connected with the input end of the selected front-end acquisition circuit; the front-end acquisition circuit is used for acquiring circuit analog quantity to be measured; the multichannel simulation control circuit is used for converting the circuit analog quantity of the front-end acquisition circuit into a voltage signal; the analog-to-digital converter is used for converting an analog signal from the multichannel simulation control circuit intoa digital signal; and the processor is used for processing the signal output by the analog-to-digital converter so as to obtain the measurement result. The invention also provides a system formed by the terminal and the meter pens, which comprises the terminal and the two meter pens; and the meter pens can also be used as handwriting pens for the terminal.

The invention provides a lithium ion battery SOC (State Of Charge) prediction method based on big data and a bp (Back Propagation) neural network. The method comprises the following steps that: collecting battery external characteristic parameters to establish a dataset of battery SOC big data; establishing a training set and a test set; constructing multiple bp neural network prediction models; independently putting the dataset in the bp neural network prediction models of different parameters to obtain measurement accuracy; and according to measurement accuracy obtained by the bp neural network prediction models of different parameters, carrying out analysis to obtain prediction results. By use of the lithium ion battery SOC prediction method based on the big data and the SOC big data, through a SOC prediction big data set, the data can be conveniently effectively mined, and prediction accuracy is guaranteed; through the distributed bp neural network prediction models, the battery issubjected to SOC accurate prediction according to battery external parameters, and accuracy is high. Especially under big data, the battery external parameters continuously change. The method still can accurately predict the value of the battery SOC, is high in usability and can be widely applied in reality.

The invention discloses a Fourier algorithm-based power system frequency measuring method. The method adopts the Fourier transform principle to extract a fundamental wave components from a voltage / current input signal subjected to interference pollution. Meanwhile, based on the change of a phase angle, the frequency of the voltage / current input signal is measured. The frequency change value can beobtained through calculation based on the sampling values of two sampling periods, so that a measured frequency value can be obtained. After that, the effective and fast numerical averaging is carried out on the calculated measured frequency value, and then the frequency correction is carried out. In this way, the measurement frequency with higher precision can be obtained. The method is ingenious and reliable. The method is high in calculation precision and fast in calculation speed is fast. The method has a good application prospect.

The invention provides a spectrum reconstruction method based on a weighted measurement matrix, comprising the following steps: S1, acquiring the spectrum values of a training sample and a test sample; S2, acquiring the camera response values of the training sample and the test sample; S3, reconstructing the spectrum value of the test sample using a pseudo-inverse method, a wiener estimation method and a principal component analysis method respectively, and getting corresponding measurement matrixes; S4, calculating the chromatic aberration between each of the spectrum values obtained through reconstruction using the pseudo-inverse method, the wiener estimation method and the principal component analysis method and the spectrum value of the test sample; S5, weighting and adding the spectrum values obtained through reconstruction using the pseudo-inverse method, the wiener estimation method and the principal component analysis method to get a new spectrum value; S6, calculating the chromatic aberration between the new spectrum value and the spectrum value of the test sample; S7, adding the weight corresponding to the minimum chromatic aberration in S6 to the corresponding measurement matrixes, and adding three values obtained together to get a measurement matrix M; and S8, using the measurement matrix to reconstruct the spectrum value.

The invention discloses an inversion method of a sea surface wind field and an apparatus thereof. The method comprises the following steps of acquiring measurement data of a GNSS reflection signal at a specular reflection point on a sea surface and processing the measurement data so as to obtain smooth measurement data; based on a DDM power integration function expression obtained based on a double-base radar observation equation, acquiring a relation between the measurement data and a sea surface scattering coefficient, and calculating the sea surface scattering coefficient at the specular reflection point according to the relation and the smooth measurement data; based on a Z-V model, acquiring a relation between the sea surface scattering coefficient and a sea surface slope probability density function, and calculating a probability density function of a sea surface slope according to the calculated sea surface scattering coefficient and the relation between the sea surface scattering coefficient and the sea surface slope probability density function; according to the probability density function of the sea surface slope, calculating a sea surface wind speed and a wind direction. By using the method and the apparatus of the invention, a sea surface state can be rapidly and accurately inverted in real time.

The invention relates to an ultrasonic wind meter, comprising a plurality of ultrasonic probes, a processing circuit and a housing which accommodates the ultrasonic probes and the processing circuit. The housing comprises an emitting surface and a reflecting surface, both of which are cambered surfaces. The emitting surface and the reflecting surface are arranged opposite to each other at a preset interval to form a space. The ultrasonic probes comprise first ultrasonic probes and second ultrasonic probes, which are distributed on the emitting surface or the reflecting surface. Emission signals of the first ultrasonic probes are emitted, then are reflected for many times within the space by the reflecting surface and the emitting surface, and are received by the second ultrasonic probes. The processing circuit is connected with the ultrasonic probes and is used to obtain receive / transmit data of the ultrasonic probes and get measurement results about wind velocity and wind direction in accordance with the receive / transmit data. The preset distance between the emitting surface and the reflecting surface of the ultrasonic wind meter is small, so that the size of the ultrasonic wind meter is reduced.

The invention discloses a method used for eliminating system frequency response influences on photo-carrier radiometry technology semi conducting material characteristic measuring equipment. The method is based on infrared radiation which is generated by a semi conducting material after absorption of focused excitation beams processed by strength periodic modulation; characteristic parameters of the semi conducting material are measured by collecting and measuring photo-carrier radiation signals; a relationship curve of the photo-carrier radiation signals and modulation frequency is obtained by changing the modulation frequency of the strength of the excitation beams; a relationship curve of the photo-carrier radiation signals and the modulation frequency under different excitation beam spot sizes is obtained by changing the space between a focusing lens and a sample; and frequency response function of the measuring equipment is obtained, and the influences of the frequency response function on semi conducting material characteristic measurement is eliminated by analyzing the relationship curve of the photo-carrier radiation signals and the modulation frequency under different excitation beam spot sizes. The method is capable of solving a problem that in traditional method measurement accuracy is influenced by relatively high measuring error, and increasing measuring accuracy of measurement on semi conducting material characteristic parameters.

The invention discloses a distance measuring method, which is used for measuring the position of a fault point of a low-current grounding system, wherein the fault point generates single-phase grounding. The distance measuring method comprises the following steps of: step 102, setting a measuring point on a bus of the low-current grounding system, and synchronously collecting a voltage traveling wave in time, wherein when the single-phase grounding is generated on an outgoing line, the traveling wave comprises a fault initial traveling wave propagated with a conducting wire through the conducting wire and a fault initial traveling wave propagated with the earth through the conducting wire; and step 104, obtaining a distance from the measuring point to the fault point according to x=v1*v2*[delta]t / (v1-v2), wherein [delta]t is the time difference of the time that the fault initial traveling wave propagated with the earth through the conducting wire reaches to the measuring point and the time that the fault initial traveling wave propagated with the conducting wire through the conducting wire reaches to the measuring point, v1 is the wave speed of the traveling wave propagated with the conducting wire through the conducting wire, v2 is the wave speed of the traveling wave propagated with the earth through the conducting wire, and x is the distance from the measuring point to the fault point. The invention further discloses a distance measuring device. According to the distance measuring method and the distance measuring device, the position of the fault point generating the single-phase grounding can be effectively detected.

The invention discloses a device for testing the sealing performance of a motor valve. The device comprises a cabinet, a motor valve state control circuit, an air pump control circuit, an air pump, a pressure sensing circuit, a numeric comparison circuit and a test result display unit. The motor valve to be tested is adjusted to be in a closed state through the motor valve state control circuit, inflation and pressurization are carried out on the motor valve in the closed state through the air pump control circuit, the internal and external differential air pressure of the inflated motor is measured through the pressure sensing circuit, a measurement result is obtained, the measurement result is compared with a preset numerical value through the numeric comparison circuit, the information with respect to test qualification of the sealing performance of the motor valve is displayed when the comparison result shows that the measurement result is larger than the preset numerical value, and the information with respect to test disqualification of the sealing performance of the motor valve is displayed when the comparison result shows that the measurement result is smaller than the preset numerical value. According to the device, the sealing performance of the motor valve can be automatically tested, and testing efficiency is improved.