138 results about "Power transformer windings" patented technology

The invention relates to an online and real time identifying device and a method for electricity power transformer winding parameters, belonging to the field of electricity power transformer techniques. The device comprises a power supply unit, a communication unit, a data collecting unit, a displaying unit and a central processing unit; the magnitude of voltage and current in the transformer of the spot goes into the data collecting unit through a voltage transformer and a current transformer respectively, then is transformed by a voltage mutual inductor and a current mutual inductor of the data collecting unit, and then is transformed into a digital quantity by a signal conditioning circuit and an A / D conversion chip; the digital quantity is transmitted to the central processing unit; the processed data by the central processor unit are transmitted to a spot epigynous machine by an RS232 or an RS485 or a CAN concentration line; the epigynous machine transfers the data to a remote monitoring machine to realize remote monitoring, which can realize an on-line and real time monitoring of the short-circuit impedance of the transformers, master the inner running conditions of the transformers at any time and realize the real time analysis and the error alarming of the transformers, thus improving the stable and reliable operation of the transformers.

The invention discloses a detection method of the looseness fault vibration of a power transformer winding, comprising the following steps of: gathering the original vibration signal of the power transformer winding and carrying out normalization processing by taking the large-sized power transformer winding as a monitoring object, and judging a special vibration state, the light looseness, the moderate looseness and serious looseness of the winding by calculating the Fourier frequency spectrum, the peak value, six time scale sampling entropies and a second-order sampling entropy. In the invention, the vibration signal which is sensitive to the change of the mechanical structure of the winding is adopted to make analysis to detect different degrees of looseness of the winding, and particularly, the invention can well detect the light looseness.

The invention discloses a method for detecting winding deformation faults of a power transformer. The method includes that different vibration characteristics of the transformer in a normal state and a fault state are combined according to running characteristics of the transformer, vibration signals are monitored by a vibration sensor mounted on the surface of the transformer, frequency spectrums of the vibration signals are analyzed, and the transformer is judged to have winding deformation faults if the ratio of 50Hz energy sum and 150Hz energy sum to (50+150Hz) energy sum to (100+200Hz) energy sum which are actually measured is obvious increased as compared with that of the transformer in the normal state and an actually measured 100Hz energy value is hardly changed or even reduced as compared with that of the transformer in the normal state. The invention further discloses a system for detecting the winding deformation faults of the power transformer. The method and the system have the advantages of obvious fault characteristics and good repeatability, and are universal for power transformers of the same type, engineering implementation is simple, and diagnosis is intuitive.

The invention relates to a failure diagnostic method for the dynamic stable state of power transformers. In the failure diagnostic method, the deformation condition of power transformer windings is analyzed by combining a frequency response process and an impedance process, the power transformers which have the same types and different serial numbers, the same windings with different phases and indexes of the correlation degree of frequency curves of the dynamic stable state are obtained by the frequency response process. The failure diagnostic method comprises the following steps of: analyzing the dynamic stable state of the power transformers according to related coefficients by synthesizing the advantages of the synthesize technology and the impedance process; when exceeding a permissible value, judging the related coefficients by the impedance process; and when numerical values of parameters also exceed the permissible value, determining that the failure of the dynamic stable state of the power transformers occurs.

The present invention relates to in-situ fault diagnosing technology for turn-to-turn short circuit of transformer windings based on change in loss. The technological scheme includes sampling and measuring the voltage and currents of transformer in both sides, calculating the power in both sides, calculating the power difference in both sides or loss of the transformer, comparing with historical data of the transformer to determine whether to exhibit turn-to-turn short circuit fault and the fault degree. The present invention makes it possible to find the turn-to-turn short circuit fault early and accurately and determine the phase the fault is in while monitoring the current, voltage, active power, reactive power, power factor, etc.

The invention relates to a test apparatus and a test method used for testing the distortion of a coil of a power transformer. The apparatus comprises an upper computer, a test unit, a DDS sweeping signal generator unit, a wide-frequency power amplifier unit and a power supply system. The test unit comprises a CPU, a data collecting unit, a logic control module and a communication unit; the CPU communicates with the upper computer through the communication unit and sends work instructions to the logic control module according to the instructions of the upper computer and simultaneously sends an instruction to the DDS sweeping signal generator unit to lead the unit to generate a corresponding sweeping signal; the sweeping signal generated by the DDS sweeping signal generator unit is transmitted to a coil on one side of the tested power transformer; the data collecting unit is respectively connected with two ends of the coil of the power transformer to collect data for regulation and convert the data into digital signals which are transmitted to the CPU for computation and then the computation result is transmitted to the upper computer through the communication unit; the logic control module is simultaneously connected with the CPU and the data collecting unit to control the data collection and transmission.

The invention discloses a power transformer winding fault simulation test method and belongs to the field of power transformer winding fault simulation test. The method comprises the following steps that: the high-voltage side of a universal power transformer is connected with an alternating current power supply through a voltage regulator, a resistor for limiting magnetizing rush current is connected in series between the voltage regulator and an electric switch; a bypass switch is connected in parallel at two ends of the resistor; the low-voltage side of the universal power transformer is connected with the low-voltage side of a tested power transformer provided with a winding fault; the high-voltage side of the tested power transformer is in short circuit; the voltage regulator is regulated, so that the tested power transformer acquires different required testing current; and a vibration signal on the surface of an oil tank of the tested transformer is acquired through a vibration sensor, and a current signal which reflects load of the tested transformer is measured through a current sensor so as to be processed and analyzed by a computer. The requirement of the power transformer winding fault simulation test on the power capacity is reduced, the method is easy in operation and readily available in parameters and has universality on similar transformers.

The invention relates to a power transformer winding deformation state multi-information detection method and device, and belongs to the technical field of power equipment fault diagnosis. The method comprises the steps of detecting current, voltage and a phase angle at a high voltage side and a low voltage side, detecting ultrasonic signals, detecting vibration signals, thereby realizing online detection, fault phase detection, fault position detection and fault type detection for the winding deformation state, and effectively solving a problem that the running state, the fault position and the fault type of a power transformer winding cannot be effectively detected because of the simplified detection signals. The device comprises a voltage transformer, a current transformer, an ultrasonic probe, a vibration sensor, a signal conditioning circuit, an AD conversion circuit and a central processing unit, wherein the output ends of the voltage transformer, the current transformer, the ultrasonic probe and the vibration sensor are connected with the input end of the signal conditioning circuit, the output end of the signal conditioning circuit is connected with the input end of the central processing unit through the AD conversion circuit, and the output end of the central processing unit is connected with a communication bus.

The invention provides a monitoring system of the internal temperatures and the stress of a power transformer winding and a monitoring method thereof. The system comprises a laser light source, an optical fiber sensor, a frequency shift detection circuit, an amplification circuit, a filer sampling circuit and a monitor, wherein light emitted by the laser light source passes through the optical fiber sensor and generates Brillouin scattering, the optical fiber sensor is pre-embedded in an electromagnetic line of the power transformer winding, the internal temperature and the stress of the power transformer winding influence the frequency of a Brillouin scattering signal of the optical fiber sensor, and the Brillouin scattering signal which is transmitted back by the optical fiber sensor is converted into an electric signal by the frequency shift detection circuit, passes through the amplification circuit and the filer sampling circuit to acquire the information of distributed temperature and stress in the winding and finally transmitted to the monitor to be displayed. The monitoring system of the invention can accurately measure the temperature and the stress of various points in the transformer winding and truly reflects the temperature of the hottest point and the stress of the winding due to deformation.

The invention discloses a power transformer winding deformation detection method based on vibration analysis. The method comprises the following steps of: (1) arranging vibration detection points, and monitoring load current and a vibration signal of each detection point in real time; (2) acquiring an impact hopping vibration signal, and judging a tripping form of a power transformer; (3) performing winding deformation diagnosis on a first power transformer according to an extracted fixed frequency; and (4) performing winding deformation diagnosis on a second power transformer according to change of a nonlinear degree. By the detection method, the vibration signals are processed and judged, so that electric connection with the power transformer is not needed, and influence on the running of the whole power system is avoided; due to the method, real-time and on-line detection is realized, and detection can be performed without stopping the power transformer, so that the influence on the running of the whole power system is avoided; small and intermediate deformation of a winding of the power transformation can be detected; and moreover, the method is easily integrated into a transformer fault diagnosis instrument and is easy to operate and favorable for popularization.

The invention provides a condition monitoring method for windings of a power transformer. The method is applied to the power transformer which operates currently. Multiple vibrating sensors are arranged on the power transformer and used for collecting multiple sets of vibration signals of the windings in the power transformer within a preset time period, vibration amplitudes of preset base frequencies in all target vibration signals in each set of vibration signals are extracted, winding vibration variations between every two adjacent vibration amplitudes in each set of vibration amplitudes are obtained, a vibration correlation model is generated according to the winding vibration variations, and then principal component analysis is carried out on the vibration correlation model so that the conditions of the windings of the power transformer can be determined. Compared with the prior art, the conditions of the windings can be obtained by collecting and analyzing vibration data of the power transformer in the normal operation process without the need of stopping operation of the power transformer, on-line monitoring is achieved, and influences on operation of a whole electric system are small.

The disclosure discloses a power transformer winding fault positioning method based on deep convolutional neural network integrated with visual identification, including 1) a winding equivalent circuit is established, and a transfer function thereof is calculated; 2) a sine wave excitation source is set at one end of the power transformer winding to obtain the amplitude-frequency characteristic curve of each winding node; 3) circuits under various fault statuses are subjected to scanning frequency response analysis to extract amplitude-frequency characteristics; 4) a feature matrix is established based on the obtained amplitude-frequency characteristics; 5) scanning frequency response analysis is performed on the diagnosed power transformer to form a feature matrix; 6) the feature matrix is converted into an image, simulation and historical detection data are used as a training set, and a deep convolutional neural network is input for training; 7) diagnosed transformer is subjected to fault classification and positioning.

The invention relates to a winding temperature measuring method of an oil-immersed power transformer. A thermal simulation experiment principle is utilized, actual heating current is obtained after the steps of acquiring related parameters of the transformer, inquiring a thermal simulation features-temperature rise and current mapping table, computing and the like, actual copper oil temperature difference is obtained according to an actual heating current lock-up table, and top oil level temperature is superposed to obtain the winding temperature. The method has the advantages that a winding temperature meter used by the transformer in field can be replaced completely, and economic cost and maintenance cost for purchasing the winding temperature meter are saved greatly; the effect as same as that of measurement by the winding temperature meter can be achieved, and the temperature of a transformer winding can be uploaded to a monitoring data network accurately and inerrably; the problem of inaccuracy of winding temperature measurement caused by influences of the environmental temperature or self defects of the winding temperature meter can be solved completely, and operation and maintenance level of a transformer substation can be increased.

The invention provides a power transformer winding fault diagnosing method, by which winding deformation fault diagnosis is performed through combination of frequency response analysis (FRA) and empirical mode decomposition (EMD). According to the power transformer winding fault diagnosing method, on the basis of energy change information in each interval during a winding deformation fault as well as the adaptive decomposing capacity of the empirical mode decomposition (EMD), a fault energy characteristic quantity of a winding is extracted to establish a fault energy database; the fault energy characteristic quantity is compared with an energy curve of a transformer winding without a fault; the change trend of the characteristic energy shows the working state of the transformer; and the method is used for establishing a mapping relationship between an intrinsic mode function of the winding deformation and an intrinsic mode function of an FRA signal and establishing an integrated fault diagnosis analysis system based on characteristic energy information of the EMD. The integrated fault diagnosis analysis system can accurately know a basic rule of the change of the transformer winding deformation energy and provides a new research way for determining the type and the degree of a transformer fault and estimating the developmental trend of the fault.

The invention discloses a method for detecting deformation of power transformer windings. The method includes the following steps that the short-circuit impedance relative change rate, the overall correlation coefficients of amplitude-frequency curves, the amplitude-frequency curves of a low frequency band, a medium frequency band and a high frequency band, the local correlation coefficients of the amplitude-frequency curves of all the frequency bands, the voltage ratio deviation and the capacitance relative change rate are acquired; the deformed windings and phase results are acquired according to the short-circuit impedance relative change rate and the overall correlation coefficients of the amplitude-frequency curves; according to the correlation coefficient of the amplitude-frequency curve of the low frequency band and the voltage ratio deviation, turn-to-turn or cake-to-cake short circuit detection results are acquired; according to the correlation coefficient of the amplitude-frequency curve of the medium frequency band and the capacitive relative change rates between the windings, local deformation results are acquired; according to the correlation coefficient of the amplitude-frequency curve of the high frequency band and the ground capacitance relative change rates of the windings, whole displacement or lead displacement deformation detection results of winding coils are acquired; the results are logically processed, and a comprehensive detection result is acquired. According to the method, reliability of the deformation detection result of the power transformer windings is greatly improved.

A method for judging a fault type of a winding based on a power transformer includes the following steps of collecting frequency response data of the transformer to be detected, drawing a frequency response curve according to the frequency response data, setting up a KLC model and selecting all parameters of the KLC model according to the type of the transformer to be detected, simulating the KLC model, obtaining changes, corresponding to the changes of different types of parameters, of the frequency response curve by changing the parameters of the KLC model, setting up the corresponding relationship between deformation of the winding of the transformer to be detected and the parameter changes of the KLC model, obtaining the parameter changes, corresponding to the frequency response curve, of the KLC model according to a frequency response curve chart of the transformer to be detected, and obtaining deformation of the winding of the transformer to be detected according to the parameter changes, corresponding to the frequency response curve chart of the transformer to be measured, of the KLC model. The KLC model of the winding of the transformer is set up according to the specific characteristics of the transformer to be detected so that the fault type of the winding of the transformer to be detected can be judged, the result is more accurate and more reliable, and the method is easy and convenient to operate.

The invention discloses a power transformer winding turn-to-turn short circuit failure detecting method based on a resistance frequency curve. The method comprises the steps that all the non-tested windings of a detected power transformer are made to be in a short circuit; the frequency sweeping signals of the preset frequency and amplitude are linearly applied to the head end of a detected winding, meanwhile, voltage signals on non-inductive resistors connected at the head end and the tail end of the detected winding are measured, and per unit values of the impedance of the detected winding under different frequencies are calculated through a computational formula; the trend curve of the impedance per unit values, changing along with the frequency, of the detected winding is drawn according to all the impedance per unit values obtained under the preset frequency, the trend curve is compared with a historical trend curve, and whether the winding turn-to-turn short circuit failure exists or not is detected according to the comparative result. The power transformer winding turn-to-turn short circuit failure detecting method based on the resistance frequency curve can overcome the defects that in the prior art, measuring difficulty is large, the accuracy degree is low and the misjudgment rate is high so as to achieve the advantages of being small in measuring difficulty, high in accuracy degree and low in misjudgment rate.

The invention belongs to the technical field of testing of transformers, and provides a deformation motoring device of a power transformer winding. The deformation motoring device of the power transformer winding comprises a data collecting unit, a data processing unit and a display control unit, wherein the data collecting unit collects voltage data and current data of the transformer winding, the data processing unit caries out calculation processing, the state of the winding is displayed on the display control unit to judge whether the winding is deformed, and meanwhile the display control unit can output a control instruction to control the data processing unit. The deformation motoring device of the power transformer winding is simple in structure, capable of rapidly and conveniently detecting the deformation condition of the power transformer winding on line, and capable of providing reliable basis for maintenance of the transformer.

The invention relates to a power transformer winding fault online monitoring device and a diagnosis method, and belongs to the technical field of power transformer fault diagnosis. The power transformer winding fault online monitoring device is characterized in that the output end of a voltage sensor and the output end of a current sensor are connected to the input end of a synchronous signal sampling circuit, the output end of the synchronous signal sampling circuit and the output end of an ultrahigh frequency sensor are connected to the input end of a signal conditioning circuit, the output end of the signal conditioning circuit is connected to the input end of a DSP (Digital Signal Processor) through an A / D conversion circuit, the output end of the DSP is connected with a PC (Personal Computer) through a CPLD (Complex Programmable Logic Device), and the PC is connected with an alarm. The diagnosis method comprises the steps of acquiring ultrasonic signals at the wall of a transformer oil tank, and finally acquiring coordinates of partial discharge through signal conditioning and A / D conversion and through DSP denoising; acquiring voltage signals and current signals, processing the signals, building an online short-circuit reactance model, acquiring a short-circuit reactance value of each phase winding, comparing the acquired short-circuit reactance value with a corresponding historical fault-free short-circuit reactance value so as to acquire the short-circuit reactance change rate, judging a range, in which the change rate is located, of an upper limit threshold and a lower limit threshold, and judging the winding operating state.

The invention discloses a simulation calculation method for temperature rise characteristics of transformer windings, which is based on finite element method, fluid mechanics and computational heat transfer, and adopts ANSYS Fluent software to realize temperature rise of transformer windings. Based on the fluid-field coupling numerical model, a simulation method of temperature rise of oil-immersedpower transformer winding hot spots is proposed.

The present invention relates to a transformer dynamic stability condition parameter testing apparatus and its diagnosis software. Said product is composed of testing apparatus and diagnosis software, and said invention is characterized by that it adopts a low-voltage reactance method to diagnose the winding deformation of power transformer and changed condition of iron-core looseness in the place so as to create a set of complete high-effective detection and diagnosis method, its detection accuracy is high, can be up to 0.2 grade.

The invention provides an online monitoring system for power transformer winding vibration signals. The online monitoring system comprises a signal amplifying circuit, an A / D (analog-digital) conversion circuit, a level conversion circuit and a signal processing module which are sequentially connected with a vibration acquisition module, the signal processing module and a man-machine interaction unit are connected with each other and then respectively connected with a PC (personal computer) through a communication module, the signal processing module computes vibration energy of different frequency bands of the power transformer winding vibration signals, the vibration energy of the frequency bands is compared with an energy threshold value by the PC, and a failure winding phase in a power transformer is judged. Compared with the prior art, the online monitoring system for the power transformer winding vibration signals can online monitor the vibration signals when the transformer is short-circuited in real time, acquired data are synchronously uploaded to the PC, a diagnosis result is displayed through a display module, and the online monitoring system gives the alarm in real time to explain the running state of a transformer.

The invention belongs to a research platform of winding deformation test for a transformer, especially to a physical simulation platform for the radial winding deformation of an oil-immersed transformer. According to a present winding deformation test platform in labs, the transformer winding is processed, including simple shift, access to a capacitor and short circuit of a turn, to simulate onsite winding deformation, an oil tank and an iron core of the transformer are not changed, the present platform is not flexible or accurate enough and is hard to simulate deformation in different shapes, positions and ranges conveniently; and when a deformed part or capacitor is replaced, the winding needs to be removed from the oil tank and causes much trouble. Distributed capacitance change caused by radial deformation of the winding is changed into distributed capacitance change caused by deformation of the oil tank, the positions of deformation blocks (6) are changed, namely, the deformed part of the winding is changed or the deformation range and degree of the winding are changed, and radial deformation of the winding is simulated simply.

The invention aims to solve the problem of on-line monitoring of transformer winding deformation failure and provides an on-line power transformer winding deformation monitoring method based on Lissajous characteristics. The invention adopts the technical scheme as follows: the method comprises the following steps: 1), after input voltage U1 is added on the input end of a normal transformer with the load of ZL, the on-line output voltage U2, input current I1 and output current I2 of the normal transformer are measured; 2), after the input voltage U1' is added on the input end of a to-be-measured transformer with the load of ZL', the on-line output voltage U2', input current I1' and output current I2' of the to-be-measured transformer are measured; 3), the output current I2' is corrected, so that the corrected output current I21 is obtained; 4) the data is processed; 5), Lissajous figures of the normal transformer and the to-be-measured transformer are constructed; 6), the characteristic values of Lissajous figures of the normal transformer and the to-be-measured transformer are extracted; 7), contrastive analysis is performed on the characteristic values of the Lissajous figures of the normal transformer and the to-be-measured transformer.

The invention discloses a power transformer winding fault diagnosis method based on a GSMallat-NIN-CNN network, and the method comprises the steps: carrying out the measurement of a vibration condition of a transformer winding through a multi-channel sensor, and obtaining multi-source vibration data of a transformer; converting the multi-source vibration data obtained by measurement into grayscaleimages by using GST gray level transformation; decomposing each grayscale image into a high-frequency component sub-image and a low-frequency component sub-image layer by layer by adopting a Mallat algorithm, and performing image fusion on a high-frequency component sub-image and a low-frequency component sub-image; reconstructing the fused grayscale images, and encoding the vibration grayscale images according to the fault state of the transformer winding; establishing a transformer fault diagnosis model based on a GSMallat-NIN-CNN network; randomly initializing network parameters, dividinga training set and a test set, and training and optimizing the network through the training set; and storing the trained network, and testing the network through the test set. According to the method,t noise in a multi-source signal is effectively suppressed, the integrity of feature information is improved, the calculated amount is reduced, and the fault diagnosis accuracy is improved.

The invention provides a power frequency follow current testing device and an application method thereof; the testing device comprises the following units: a power transformer used for converting a power grid voltage into a power frequency voltage, wherein the power transformer winding inter-turn insulating material employs yellow varnished silk, and the inter-layer insulating material employs fiberglass cladding flat wire; an impact voltage generator with the charging capacitor electric capacity as 0.05 [mu]F, a wave front resistor resistance as 80 [omega] and a wave tail resistor resistance as 2100 [omega]; the impact voltage generator is connected in series with an impact side protection circuit, and then the output end is connected in parallel with a tested product; the power transformer and a power frequency side protection circuit are connected in parallel, and then the output end is connected in parallel with the tested product; the testing device also comprises a control measuring circuit used for determining whether to trigger to form an impact voltage or not according to the power frequency power phase. The testing device can better simulate the lightning wave conditions happening in network operations, can bear higher overvoltage and overcurrent, thus ensuring high reliability, and using fewer protection circuits.

Disclosed is an intelligent on-line diagnosis method for winding deformation of power transformer. When a transformer is subjected to short-circuit shock or transportation collision, transformer windings may undergo local twisting, swelling or the like under the action of an electric power or mechanical force, which is called winding deformation and will cause a huge hidden danger to the safe operation of the power network. Commonly used diagnosis methods for winding deformation are all off-line diagnosis methods, which have the disadvantages that transformers need to be shut down and highly skilled operators are required. The present invention provide an intelligent on-line diagnosis method for winding deformation on the basis of combination of information entropy and support vector machine. By carrying out feature extraction of current and voltage signals based on permutation entropy and wavelet entropy, integrating the variation of the monitoring indicators of the power transformers in complexity, time-frequency domain and the like and automatically learning the diagnostic logic from fault features through the machine learning algorithm, intelligent diagnosis of winding deformation is realized, thereby reducing labor costs and improving diagnosis efficiency.

The present invention discloses an on-line monitoring method and an on-line monitoring system for an axial pressing state of an electric power transformer winding. A natural frequency of an upper layer wire cake of the winding is extracted from vibration signals of an upper surface of a transformer oil tank according to a characteristic that the natural frequency of the upper layer wire cake of the winding reduces under the action of a stable component of an axial Ampere force, a degradation of the axial pressing state of the winding, namely the reduction of a pre-tightening force, results in the reduction of the natural frequency of the wire cake of the winding, and thereby on-line monitoring the axial pressing state of the large power transformer winding by following and observing a variation trend of the natural frequency. The on-line monitoring system includes a vibration signal acquisition module, a load current acquisition module, an analysis control module, a storage module, an output display module and a sound alarm module, wherein, the vibration signal acquisition module, the load current acquisition module, the storage module, the output display module and the sound alarm module are connected to the analysis control module respectively. The on-line monitoring method and the on-line monitoring system have the advantages of a distinct physical significance and a simple realization way.

A power transformer winding deformation reverse acquisition method based on topological optimization includes the steps of building an equivalent circuit model of a transformer winding and acquiring afrequency response function of the equivalent circuit model of the transformer winding, calculating flexibility of the frequency response function of the equivalent circuit model to element parameters, correcting parameter of a simulated equivalent circuit model according to the frequency response function obtained through test, and performing reverse acquisition on deformation status of the transformer winding by a topological optimization method based on a flexible deformation unit. High calculated amount generated in the process of directly utilizing electromagnetic field finite elements to calculate the frequency response function is avoided and correction efficiency is improved; besides, the topological optimization method is introduced to perform visual reduction on the deformed winding, and thus the winding deformation acquisition precision is improved.