530 results about "Phase displacement" patented technology

The invention relates to the technical field of abnormity early warning, in particular to a transformer load abnormity early warning method and system, and the method comprises the following steps: obtaining an electrical parameter sequence and correcting a phase, constructing a current and power change rate sequence, extracting a load fluctuation trend factor, calculating a disturbance growth rate and judging whether the disturbance growth rate crosses a boundary, and recognizing a power gradient abrupt change feature. And judging whether periodic overlapping exists or not, and outputting a combined abnormity early warning identification sequence. According to the invention, by introducing phase difference and time base offset calculation, constructing a phase-aligned electrical parameter sequence group, and analyzing a periodic rate mean value and an integral quantity, disturbance trend evaluation is realized, a power gradient sequence is used to identify a section mutation interference signal, and a joint anomaly identification mechanism is constructed on two dimensions of a period and a section. The method achieves the composite judgment of the load disturbance trend and sudden change interference, effectively improves the accuracy and response time efficiency of load abnormity early warning, and reduces the recognition error risk caused by hidden fluctuation or local sudden change.

The invention relates to the technical field of electrical detection, in particular to an electricity meter load monitoring method and system based on an electric energy quality analyzer, and the method comprises the following steps: extracting three-phase voltage phase deviation characteristics in a disturbance period, combining with the comparison of a frequency band change trend and fundamental frequency power, recognizing an interference coupling section, and analyzing a jump frequency point; and outputting an ammeter load monitoring result. According to the method, the phase deviation angle of the three-phase voltage is extracted in the voltage disturbance period, and the cross-phase synchronization index is constructed, so that the synchronous response characteristics of different loads to disturbance can be accurately revealed, and the accuracy of load response attribution judgment is enhanced. On the basis of cross-phase synchronous analysis, a corresponding relation between frequency band characteristics and response attribution is constructed, so that load response subdivision has a phase difference identification capability and a frequency behavior calibration capability, and the discrimination robustness under a multi-source interference background is improved.

The invention relates to a rectification harmonic suppression control method for a double reverse star transformer. The method comprises the following steps: establishing a rectifier bridge arm phase characteristic parameter table in a control platform, and recording a theoretical conduction phase, winding attribution and waveform synchronization characteristics of a bridge arm; in the operation process of the rectification control unit, the output current of a transformer and the conduction state of a bridge arm are collected, and a rectification operation state data set is generated; and calculating bridge arm conduction phase deviation, and analyzing a corresponding harmonic component to obtain a mapping relation between a bridge arm state and harmonic distribution. And judging whether the current bridge arm configuration meets the phase coverage requirement of the target rectification pulse number or not according to the mapping result, and if not, selecting a standby bridge arm group with a preset phase difference and generating a switching instruction. And the rectification control unit responds to the instruction to lock the current bridge arm conduction path and release the target bridge arm group so as to realize bridge arm resource dynamic reconstruction and rectification performance optimization. Harmonic waves can be effectively suppressed, and the topology adaptability and the output quality of the rectification system are improved.

Disclosed in the present invention are a dual-end monitoring-based partial discharge source localization method and system for high-frequency partial discharge of a high-voltage cable. The method comprises: acquiring operation data and phase velocity test data of a high-voltage cable; when a partial discharge fault occurs in the high-voltage cable, collecting partial discharge signals on two sides of the high-voltage cable by means of sensors on the two sides of the high-voltage cable; performing Fourier transform respectively on the basis of the partial discharge signals on the two sides to obtain amplitude-frequency characteristics of the partial discharge signals, and preprocessing the collected partial discharge signals on the basis of the amplitude-frequency characteristics to optimize and improve a phase difference algorithm; and by incorporating the phase velocity test data of the high-voltage cable, using the improved phase difference algorithm to perform partial discharge source localization on the faulty cable. In the present invention, dual-end monitoring is used to reduce the attenuation of signals caused by long-distance transmission, and synchronization of two sensors is performed using a PTP protocol, effectively reducing errors; and in addition, during monitoring, partial discharge source localization is performed using the improved phase difference algorithm, which is conducive to resisting external interference, and there is no need to determine the time of arrival, greatly improving the positioning accuracy.

The invention provides a clock signal generating circuit, a wired communication transceiver and electronic equipment, and the circuit outputs a first DC voltage comprising phase difference information and frequency difference information of a reference clock signal and a feedback clock signal through a phase frequency detection module. The pulse generator generates a narrow pulse signal based on the DC voltage and a reference clock signal, the oscillation frequency of each secondary ring oscillator in the cross-coupled ring oscillator is controlled by the first DC voltage, and the cross-coupled loop performs synchronous coupling and phase sequence adjustment processing on each secondary ring oscillator. One output node in the cross coupling ring oscillator receives the narrow pulse signal, frequency and phase locking is completed in an injection locking mode, and the frequency divider is used for conducting frequency division processing on any high-frequency clock signal and outputting a feedback clock signal. Therefore, a high-frequency multi-phase clock signal with low phase noise and high phase precision can be generated by using the low-frequency reference clock signal.

The invention discloses a power capacitor bank dielectric loss on-line monitoring method, particularly relates to the technical field of power system equipment insulation state monitoring, and is used for solving the problems of insufficient signal synchronization precision and large dielectric loss calculation error under complex electromagnetic interference in the existing method. The method comprises the following steps: acquiring voltage and current signals in real time and dynamically tracking fundamental frequency; intercepting a main period waveform, constructing phase space trajectory analysis complexity, and generating distortion features in combination with symbol sequence transfer entropy; dynamically adjusting filtering parameters based on the distortion characteristics and the Lyapunov exponent gradient; calculating a high-precision phase difference through zero crossing point interpolation correction and sliding window filtering, and finally determining a dielectric loss value; through dynamic frequency tracking, nonlinear feature collaborative analysis and an adaptive filtering strategy, noise interference is effectively suppressed, phase synchronization precision and dielectric loss calculation reliability are improved, and accurate and real-time monitoring support is provided for insulation performance evaluation of the power capacitor bank.

The invention relates to the technical field of electric power engineering automation, in particular to a low-voltage equipment power factor automatic adjusting system and method based on end compensation, and the system comprises a load monitoring module, a compensation strategy generation module, an end compensation execution module, a dynamic balance correction module and an effect evaluation module. According to the invention, the sequential relationship between the load fluctuation and the compensation demand can be accurately identified by continuously monitoring the current waveform, the voltage waveform and the phase difference change trend of the low-voltage equipment, and the compensation strategy is dynamically formulated in combination with the response duration and the compensation demand matching rule, so that the compensation response agility and the matching property of the fluctuating load are improved; dynamic scheduling is carried out according to the capacitor switching capacity and the combination relation in compensation execution, switching weight configuration is analyzed and optimized through the power factor change rate before and after compensation and the load synchronization characteristic, the dynamic balance of the compensation process is enhanced, the power factor stability and the load fluctuation matching capacity after compensation are effectively improved, and the compensation efficiency is improved. And the adaptability and continuity of the adjusting effect are enhanced.

The invention discloses a six-phase motor and a harmonic suppression hybrid winding design method thereof, and relates to the technical field of motors, and the method comprises the steps: obtaining a slot vector star diagram under six-phase current phase difference optimization based on a three-phase motor slot vector star diagram under the condition that the pole slot cooperation of the current motor meets the winding design requirement; based on the adjusted slot vector star graph and a coil pitch determined according to pole slot matching, a winding arrangement mode is designed under the requirement for balancing magnetomotive force amplitude; based on the designed winding arrangement mode, obtaining the current magnitude and phase of different terminals in each phase by introducing current with preset magnitude and phase; and determining the number of turns of each terminal in each phase under the constraint of a principle that magnetomotive force amplitudes generated by each coil are equal based on the current magnitude and the phase of different terminals in each phase. According to the invention, comprehensive suppression of stator magnetomotive force harmonics is realized through pole slot cooperation and six-phase current phase difference optimization in combination with a split-phase belt winding structure design.

The invention relates to the field of electric power, and discloses an electric energy metering method, system and device and a storage medium, and the method comprises the steps: employing an FIR zero compensation angle difference algorithm to correct a synchronization error angle difference between a current signal and a voltage signal, employing a self-convolution cascade zero-pole low-pass filter algorithm to carry out the filtering processing of a synchronization current signal and a synchronization voltage signal, and obtaining a current signal and a voltage signal; correcting a real-time phase difference between the filtering current signal and the filtering voltage signal by adopting a high-real-time FIR zero-step angular difference algorithm to obtain a corrected current signal and a corrected voltage signal, sampling to obtain current data and voltage data, and obtaining an initial electric energy metering result according to the current data and the voltage data; and obtaining environmental factors, calling a pre-trained electric energy metering error prediction model to obtain an electric energy metering prediction error, and obtaining a final electric energy metering result according to the initial electric energy metering result and the electric energy metering prediction error. The electric energy metering method with high accuracy and high linearity is provided, and the problem that an existing electric energy metering mode is large in measurement error is solved.

The invention relates to the technical field of fault detection, in particular to an electrical fault detection control system which comprises a phase monitoring module, an abnormity positioning module, a current control module and a result verification module. According to the method, the phase difference is calculated by combining collection and dynamic time warping, an abnormal mark is generated by comparing a phase tolerance threshold value, the phase delay detection precision is improved, based on an adjacent node phase difference value sequence, the slope kick is analyzed through linear regression, the candidate section judgment accuracy is enhanced, and a constant current source collects a multi-node voltage difference value; the Kalman filtering smoothes the voltage drop difference and compares the threshold value, improves the anti-interference capability of the complex working condition, compares the overlapping degree of the path coordinates and forms a closed loop verification mechanism with a re-check instruction, guarantees the reliability of the positioning result, shortens the fault response time through the multi-stage collaborative optimization, reduces the misoperation, and improves the discrimination robustness through the dynamic modeling and multi-source signal fusion. The dependence on experience or threshold is reduced; and the self-adaptive capability is enhanced.

The invention relates to the technical field of fault detection, in particular to an electrical equipment fault diagnosis method and system, and the method comprises the following steps: constructing a ratio group of a trigger incremental sequence quantity and a frequency spectrum cluster set based on a partial discharge pulse interval, deducing impedance frequency boundary migration, analyzing a conductor heating and cooling rate difference, and forming thermal response lag information. According to the method, frequency spectrum energy evolution characteristics are extracted through partial discharge pulse interval dynamic behaviors, a frequency migration path is constructed to reflect an impedance boundary fluctuation process, hysteresis effect characteristics are extracted in combination with thermal inertia response differences in a temperature rise stage, and the impedance boundary fluctuation is determined. And analyzing a voltage and current phase fluctuation rule and deducing a change trend of a combined feature, establishing a layer-by-layer progressive judgment logic between multi-stage dynamic coupling features, realizing evolutionary process tracking from local disturbance to a global abnormal state, and improving a fine-grained identification level of an abnormal mechanism in an electrical equipment operation behavior.

The invention relates to the technical field of motor state monitoring, in particular to a motor state monitoring method and system based on data driving, and the method comprises the following steps: synchronously collecting a motor voltage signal amplitude time domain sample and a motor current signal amplitude time domain sample for a power frequency period in a motor operation state; and calculating an instantaneous phase difference between each corresponding sample point to obtain an instantaneous phase difference original data stream of the motor. The method comprises the following steps: synchronously acquiring voltage and current amplitudes during operation of a motor in real time, and calculating an instantaneous phase difference between the two amplitudes to obtain an electromagnetic state original data stream; further executing high-pass filtering and performing spectral analysis to filter interference signals and low-frequency trend influences, and improving the recognition precision and robustness of instantaneous phase difference jitter features; meanwhile, voltage pulses are actively injected into the winding, echo signals are collected, and rapid capturing and positioning of the abnormal state of the winding are achieved through propagation time delay calculation and impedance characteristic construction.

The invention discloses an AC excitation system rotor initial position on-line identification method and system, and the method comprises the steps: collecting a stator three-phase voltage signal when a stator is no-load, carrying out the Clarke conversion of the signal, obtaining a voltage component under a static coordinate system, and carrying out the low-pass filtering processing; calculating a stator flux linkage based on the stator current and the processed voltage component, and calculating a rotor flux linkage based on the rotor current; the rotor initial position offset is continuously accumulated through closed-loop adjustment by calculating the stator and rotor flux linkage angle and the phase difference until the phase difference approaches zero, and the accumulated rotor initial position offset is output; and combining the mechanical angle output by the encoder with the accumulated rotor initial position offset to obtain a corrected rotor position angle, and updating the corrected rotor position angle to an excitation system. According to the method, the in-phase characteristics of stator and rotor flux linkages are utilized, and the optimally designed low-pass filter is combined, so that the identification precision of the initial position of the rotor is remarkably improved, and the zero offset of the encoder is effectively compensated.

The invention relates to the technical field of motor control, in particular to a harmonic gear motor based on double encoders and a control method thereof, which comprises the following steps: processing linear Hall element signals output by a rotor shaft encoder, including high-frequency noise suppression, direct-current bias calibration, amplitude normalization and phase difference calibration, to obtain accurate orthogonal signals; a double-dq rotating coordinate system phase-locked loop algorithm is adopted, the calibrated orthogonal signals are processed, and the high-precision real-time angle of the motor rotor is obtained through calculation; based on a signal of an output shaft encoder, matching with a preset angle partition of the harmonic reducer, and identifying an absolute position sector where the current output shaft is located; the rotor angle and the sector angle of the output shaft are fused to generate a high-resolution absolute angle of the output shaft; and based on the fused angle information, a magnetic field orientation control algorithm is adopted to drive a motor, and closed-loop control is achieved.

The invention relates to a multi-source micro-grid inertial support detection method and device and a storage medium. The method comprises the steps that S1, a discretized original voltage sequential sequence and a discretized original current sequential sequence are collected; s2, respectively extracting a first voltage sequence and a first current sequence corresponding to a measurement moment based on the original voltage sequential sequence and the original current sequential sequence; s3, obtaining a measurement frequency and a voltage and current phase difference based on the first voltage sequence and the first current sequence, and obtaining an active power based on the voltage and current phase difference; s4, obtaining a reference frequency and a reference power based on the measurement frequencies and the active powers at the plurality of measurement moments; and S5, based on the reference frequency and the reference power, combining the measurement frequency and the active power at the measurement moment to obtain the equivalent inertia. Compared with the prior art, the method has the advantages that the measurement accuracy of the equivalent inertia in the multi-source micro-grid environment is improved, and the like.

The invention discloses a power distribution network island grid-connected smooth switching control method and system, belongs to the field of power distribution networks, and particularly relates to power distribution system control, and the method comprises the steps: carrying out the feature extraction of a first voltage signal at the island side of a power distribution network and a second voltage signal at the main network side of the power distribution network, and obtaining a quantitative feature value; inputting the quantized characteristic value into an inrush current prediction model to output a closing inrush current prediction range, calculating a width value and a peak amplitude of the prediction range corresponding to each phase time sequence to identify a target phase interval, and evaluating stability contribution of each phase time sequence in the target phase interval to determine a target closing time sequence; and adjusting the output characteristic parameters of the inverter according to the target closing time sequence to obtain an inverter output signal, performing iterative optimization to adjust phase difference compensation, and generating a grid-connected control instruction to control grid-connected smooth switching of the power distribution network island, so that smooth switching during grid connection of the power distribution network island and the main network can be realized, and the stability of the power distribution system is improved.

Embodiments of the present application relate to the technical field of power supplies, and disclosed are a microgrid synchronization control method and a microgrid power supply system. In the embodiments of the present application, a central controller can directly send a phase difference between voltages on two sides of a grid-connected switch to a power converter in a microgrid, and the power converter directly performs phase compensation on a voltage between the power converter and the grid-connected switch instead of performing phase compensation on the voltage between the power converter and the grid-connected switch in a phase closed-loop control mode by the central controller. Compared with the phase closed-loop control mode, a direct phase compensation mode can quickly realize the phase synchronization of the voltages on the two sides of the grid-connected switch. Therefore, the microgrid synchronization control method provided by the embodiments of the present application can improve the speed of synchronization control.

The invention relates to a light-weight network-based voltage wave crest and wave trough rapid identification method and system, and the method comprises the steps: constructing a multi-dimensional input vector through voltage and load current dual-channel synchronous collection and feature fusion; real-time reasoning is carried out on the voltage wave crest and wave trough probability based on a lightweight neural network, and a high-confidence-coefficient triggering mark signal is generated in combination with dynamic threshold value comparison; mapping the trigger mark into a multi-phase conduction time sequence deviation matrix by using an asymmetric phase deviation algorithm, and dynamically adjusting a phase difference parameter in combination with a load current; and through a complementary PWM control instruction group generation and closed-loop optimization mechanism, ripple cancellation of staggered conduction of the multi-phase switch tubes is realized. The method solves the problem of insufficient ripple suppression caused by high false triggering rate and rigid phase distribution in traditional fixed threshold detection, remarkably improves the voltage stability and dynamic response speed in a sudden change scene from light load to heavy load, and can be widely applied to high-precision power supply systems such as data centers and communication equipment.

The invention provides a thin-wall structural part milling chatter suppression method and device based on main shaft rotating speed parameter adaptive regulation and control, electronic equipment and a storage medium. According to a stability lobe graph, a rotating speed area is divided, and a continuous variable rotating speed dominant area and a discrete variable rotating speed dominant area are determined; if the milling chatter is in a low-speed area, sine continuous variable-speed modulation is adopted, modulation parameters are optimized based on an energy minimization criterion, and a continuous variable-speed curve is generated; if the target is in the high-speed area, calculating a stable target rotating speed according to a phase difference matching condition, and generating a discrete rotating speed sequence through low-pass filtering and saturation constraint processing; and when the stability improvement amplitude is lower than a threshold value, the rotating speed is divided into a discrete variable rotating speed dominant area, and a discrete variable rotating speed strategy is adopted. An additional vibration suppression device or hardware transformation is not needed, and the method has the advantages of being easy and convenient to implement and low in cost and has the remarkable effect in the aspect of improving machining stability and efficiency.

The invention relates to the technical field of power grid switching, and provides a grid-connected and off-grid seamless smooth switching method and device, electronic equipment and a storage medium thereof. The method comprises the following steps: acquiring a power grid phase angle and dq-axis voltage in real time through SRF-PLL phase locking, performing Clarke-Park conversion on VSG output current, and calculating active power and reactive power; based on the power deviation, the virtual inertia and the damping coefficient, dynamic optimization is carried out to obtain self-adaptive inertia and damping; performing secondary voltage compensation by combining the dq-axis voltage amplitude difference and the real-time reactive power to generate excitation voltage; frequency compensation is realized by using a phase difference and a dynamic phase tracking model; a switching instruction is generated through multi-threshold judgment, linear transition is conducted on reference current and reactive power through a transition function during switching, a non-jump current instruction is output, and grid-connected and off-grid seamless switching is achieved by closing PWM. According to the invention, grid-connected and off-grid seamless switching and high-precision voltage frequency control are realized through multi-threshold judgment, soft-closed PWM and the like.

A method, processing system and control circuit for driving a linear resonance actuator, LRA, in an electronic device, comprising generating a drive signal to drive the LRA, wherein the frequency of the drive signal is initially set to an initial frequency (fi); determining a phase difference (Δφ) between a voltage and a current over the LRA; and adjusting the frequency of the drive signal using a feedback control loop such that the determined phase difference (Δφ) converges to a non-zero pre-determined phase difference at resonance (Δφ0). The invention further relates to an electronic device with a linear resonant actuator driven using such method,processing system or control circuit.

The invention relates to the technical field of fault diagnosis, and discloses a mutual inductor fault diagnosis method and system based on an intelligent algorithm, and a storage medium. The method comprises the following steps: acquiring an output signal of a secondary side of a mutual inductor at a preset sampling frequency, performing de-noising processing on the output signal, and converting the output signal into time sequence data; performing time domain feature extraction on the time sequence data to obtain a first data feature and a second data feature of the target physical quantity, extracting a zero-sequence current component and a zero-sequence voltage component from the time sequence data, and calculating a phase difference between the zero-sequence current and the zero-sequence voltage as a zero-sequence feature; whether the transformer is abnormal or not is judged, if yes, a multi-modal input vector is constructed based on the time domain features, the zero sequence features, the environmental parameters, the temperature parameters and historical fault records, the multi-modal input vector is input into a pre-trained multi-task deep learning model, and the deep learning model outputs a fault diagnosis result. According to the invention, the fault diagnosis precision of the mutual inductor is improved.

The invention discloses a voltage sag detection method for a 0.4 kilovolt low-voltage power distribution network, and relates to the technical field of electric energy quality detection, and the method comprises the steps: collecting electric power data, calculating an instantaneous synchronization degree by using a cosine function, calculating an initial disturbance index by using a direct difference method, iteratively updating the disturbance index by using a weighted propagation iteration method, and constructing an updated disturbance vector. Generating a virtual sequence by using bitwise XOR operation, calculating a first-order difference of the virtual sequence, calculating a mean value, defining the mean value as a disturbance sensitivity index, regarding the disturbance sensitivity index as a scalar field, calculating vorticity of nodes, and defining the vorticity as global vorticity intensity; instantaneous phase difference of nodes is calculated by Hilbert transform, disturbance indexes are updated in combination with a cosine function and a weighted propagation iteration method, detection sensitivity and accuracy are improved, a mode of generating a virtual sequence through bitwise exclusive-or operation is introduced, global vorticity intensity is calculated in combination with connection weight between the nodes, and the detection accuracy is improved. And the precision and reliability of disturbance analysis are enhanced.

The invention discloses a phasor closed optimization control method for secondary harmonic suppression of a direct-current micro-grid, and the method comprises the steps: taking the square of a total harmonic current amplitude as a measurement standard, and searching an optimal harmonic reference phase through a gradient descent method; adjusting the harmonic phase injected into the direct current system by adjusting the phase of the voltage of the alternating current side inverter or changing the harmonic phase generated by the single-phase inverter by adjusting the voltage phase of the single-phase inverter; and an alternating current reference current generating ring is constructed by adopting a bidirectional DC-DC converter in a step-up or step-down mode to ensure that the absorption current and the residual harmonic waves are synchronous in phase, so that the residual harmonic waves are filtered out. According to the invention, under the condition of not damaging the electric energy direct current of the alternating current side, the second harmonic current injected into the direct current micro-grid is reduced, the configuration capacity of the filter is reduced, and meanwhile, the complete absorption of the amplitude and phase difference between the compensation current of the parallel filter and the actual second harmonic current is realized.

The invention belongs to the technical field of magnetic variable measurement, and particularly relates to a power driving compensation method and system for magnetostrictive load characteristic monitoring, and the method comprises the steps: obtaining a reference zero point of magnetic performance evolution in a cold state environment of an electromagnetic system according to the center frequency of the electromagnetic system; calculating a current main frequency impedance module value and a phase difference through an electrical parameter characterization method, and obtaining a thermal drift index reflecting a hysteresis loop distortion degree in combination with a reference zero point; obtaining correction factors of all orders based on the thermal drift index and the average output power at the current moment, and dynamically updating a coefficient vector of the inverse model; and constructing a pre-distortion driving voltage signal capable of counteracting nonlinear interference by using the new coefficient and the ideal guided wave voltage sequence, and inputting the pre-distortion driving voltage signal to a power amplifier to drive the magnetostrictive transducer. According to the invention, the problem of predistortion failure under a variable-temperature working condition in the prior art is solved, and the signal-to-noise ratio of high-power long-distance guided wave detection is remarkably improved.

The invention provides a low-voltage direct-current power distribution network small-current grounding fault identification method based on active injection and phase characteristic analysis and a related device, and the method comprises the steps: responding to a starting criterion of fault detection, and triggering an active signal injection strategy; collecting the positive and negative electrode current of the head end of each feeder line and extracting the zero-mode current of the head end of each feeder line; calculating the total zero mode current of the system; aligning the zero-mode current of each feeder line with the total zero-mode current; extracting instantaneous phases of the zero-mode current of each feeder line and the total zero-mode current by adopting a wavelet transform method; calculating an average phase difference between the zero-mode current of each feeder line and the total zero-mode current; and judging whether the cosine value of the average phase difference is smaller than a set value, and if so, judging that the section to which the corresponding feeder belongs has a fault. According to the invention, the fault features are enhanced by using the active injection detection signal, and the criterion is constructed through zero-mode current processing and phase analysis, so that the fault identification capability is improved under the condition of not adding an additional injection device.

The invention discloses a pre-synchronization control method for a network-building converter based on a virtual synchronous generator, and the method comprises the steps: collecting the three-phase voltage of the output end of the virtual synchronous generator VSG and the three-phase voltage of a power grid side, converting the three-phase voltage into a voltage component in a two-phase static coordinate system through Clark conversion, and extracting a positive-sequence component; calculating a phase difference compensation coefficient based on the positive sequence component; based on the phase difference compensation coefficient, adaptively setting a PI parameter; and calculating and adjusting the amplitude of the internal potential to finish pre-synchronization. In the working process, through self-adaptive PI parameter setting and amplitude accurate judgment, the pre-synchronization time is shortened, the grid-connected impact current is reduced, and the grid-connected success rate of the micro-grid in a weak grid scene is improved.

The invention discloses a three-phase meter power flow reversal detection method, which relates to the technical field of electric power, and comprises the following steps of: firstly, acquiring original waveform data in a power grid, identifying a power disturbance frequency point, eliminating a voltage component and a current component on the power disturbance frequency point by using a band elimination filter so as to acquire filtered waveform data; s3, dynamically updating a stability threshold value to judge the consistency of the power structure before and after filtering, triggering an early warning instruction, receiving the early warning instruction, analyzing whether the voltage and current loads of the power system are in a balanced state or not, if so, repeating the step S3 to update a power disturbance frequency point, and if not, executing the step S4; if yes, identifying a power inversion result of the power system through a phase difference compensation mechanism, and the power inversion result is used for reflecting whether the power is inverted or not.

The invention discloses a withstand voltage test method and device for transformer production and a medium, and belongs to the technical field of transformer tests.The method specifically comprises the steps that firstly, a frequency conversion test power source is connected to the input end of a to-be-tested transformer and connected with a high-precision non-inductive shunt in series, and an environment monitoring unit is started to lock temperature and humidity in real time; the control power supply outputs a standard sine test voltage with a preset frequency; then, a high-frequency broadband acquisition card is used for synchronously obtaining instantaneous waveform data of voltage and total leakage current of the transformer, and analog signals are converted into discrete digital signals; performing second-order difference on the total leakage current signal to position a high-frequency abrupt change point, and reconstructing a smooth waveform through Lagrange interpolation; a current phase difference is calculated by taking a voltage zero crossing point as a phase reference, a complex plane coordinate system is constructed, and resistive and capacitive current components are calculated through waveform amplitude projection; and finally, according to the temperature and the humidity, a correction coefficient is called to normalize the resistive current, and a quality inspection result is output by comparing an insulation safety threshold.

The invention discloses a dry-type air-core reactor loss measurement method, device and system, and relates to the technical field of reactor loss factor measurement. The method comprises the following steps: in response to an obtained electrical parameter signal of the dry-type air-core reactor, performing Fourier transform on a voltage signal in the electrical parameter signal, and determining the fundamental wave purity of the dry-type air-core reactor; the electrical parameter signal comprises a voltage signal and a current signal, the voltage signal comprises a voltage amplitude and a voltage phase, and the current signal comprises a current amplitude and a current phase; based on the current amplitude and the phase difference between the voltage phase and the current phase, determining a harmonic judgment value of the dry-type air-core reactor; determining a defect correction coefficient of the dry-type air-core reactor based on the phase difference between the voltage phase and the current phase; and determining the loss factor of the dry-type air-core reactor based on the fundamental wave purity, the harmonic judgment value and the defect correction coefficient of the dry-type air-core reactor. According to the invention, the identification precision of the defects of the dry-type air-core reactor can be improved.