1364 results about "Utility frequency" patented technology

The invention discloses a multi-parameter measurement system and method for a power frequency non-partial discharge test transformer, and relates to the technical field of state monitoring of high-voltage test equipment and power equipment, and the system comprises a synchronous trigger unit which is connected to a power frequency voltage signal collection end and is used for detecting a zero crossing point of a power frequency voltage signal and generating a synchronous trigger signal, a power frequency period is divided into a plurality of sub-windows with equal phase angles. According to the multi-parameter measurement system and method for the power frequency non-partial discharge test transformer, the problem of phase mismatch of a power frequency signal and a high-frequency partial discharge signal in traditional multi-parameter measurement is effectively solved through a power frequency phase locked synchronous trigger mechanism and a dynamic noise suppression technology; and the positioning precision of the partial discharge source and the insulation defect diagnosis reliability are improved. The nanosecond-level time sequence error control is realized, and the power frequency coupling interference is inhibited while the details of the high-frequency pulse are kept by combining a phase correlation dynamic filtering strategy, so that the signal-to-noise ratio of the weak discharge signal is improved.

The invention discloses a distribution network cable traveling wave fault early warning and positioning method and system, and the method comprises the steps: installing a device in a ring main unit, collecting a high-frequency traveling wave current and a power frequency current, and recognizing a grounding fault through a transient zero sequence comparison method and a high-frequency traveling wave polarity algorithm; weak traveling wave signals generated by insulation defects are monitored to carry out hidden danger early warning; traveling wave arrival time difference is measured through double-end distance measurement, and the position of a fault point is calculated in combination with line parameters; and early warning and positioning results are transmitted to a master station through 4G / 5G and 101 / 104 protocols. The system comprises a data acquisition module, a signal processing module, a fault positioning module, a hidden danger early warning module, a master station communication module and a master station module which work cooperatively. The method and the system are high in positioning precision, can realize accurate fault positioning and hidden danger early warning, support live-line installation, are suitable for various scenes, effectively solve the operation and maintenance problem of the distribution network cable, and improve the power supply reliability.

The invention relates to the technical field of electrical performance testing, in particular to a water supply equipment electrical performance detection system based on artificial intelligence, which comprises an electrical parameter acquisition module, an energy efficiency analysis module, an insulation performance evaluation module and a comprehensive diagnosis module. According to the invention, a three-phase voltage and current root-mean-square value is dynamically calculated through a broadband current transformer and a sliding window integration method, a 50Hz fundamental component amplitude is extracted to separate power frequency and high frequency harmonic waves, a continuous period energy efficiency ratio standard deviation triggers an insulation detection threshold value, and a parameter fluctuation and insulation degradation response mechanism is established. Harmonic interference correction synchronous processing energy efficiency ratio and leakage current integration, the detection error being lower than 5%, temperature rise rate linear regression and bearing current threshold value cooperative determination, winding aging cross validation, fault misjudgment rate reduction to 26%, closed-loop detection fusion transient capture, dynamic threshold value triggering and multi-parameter diagnosis, early warning success rate reaching 92%, and positioning response being reduced to 3 seconds.

The invention provides a multi-dimensional electrical equipment insulation analysis and evaluation method, and relates to the technical field of electrical equipment insulation online detection and intelligent diagnosis. According to the method, an electrically isolated direct current detection channel is constructed in a neutral point small resistance grounding system, controllable direct current detection signals are injected, micro direct current leakage response signals are collected, and after zero drift correction, temperature compensation and power frequency ripple suppression are carried out, layered attribution is carried out in combination with primary system topology and an equipment ledger, and a multi-dimensional response matrix is formed. According to the method, environment and working condition normalization is realized through factor rejection and robust pull-back, a mechanism model containing leakage channel equivalent parameters and path constraints is established, multi-working-condition data is fused to calculate equivalent insulation parameters and credibility indication quantity, and a multi-dimensional insulation representation vector is generated. And performing time sequence analysis on the representation vector, extracting degradation and abrupt change characteristics, outputting a health index and a risk level, and realizing quantitative evaluation and intelligent early warning of the insulation state.

Provided in the present invention is a transformerless unified power quality conditioner, comprising a three-phase conditioner substructure, wherein each phase of the conditioner substructure can comprise an ANPC three-level converter and an output half-bridge module connected to the ANPC three-level converter. Also provided are a corresponding modulation method and system and a corresponding control method and system. Compared with existing voltage regulation apparatuses, the transformerless unified power quality conditioner and the modulation method and control method therefor provided in the present invention do not include a power-frequency transformer in the topology, but use a three-level converter to expand ports to realize voltage regulation, thus having the advantages of lower costs, smaller size, smaller footprint, lower loss, etc.

The invention relates to the field of cable monitoring, in particular to a high-voltage cable running state comprehensive monitoring method based on a TMR magnetic sensor. According to the method, firstly, a TMR magnetic sensor is adopted to collect sheath current and partial discharge pulse signals of a cable joint grounding wire, then amplification, filtering and AD change are carried out, Fourier transform is carried out, and low-frequency signals and high-frequency signals are separated out; carrying out frequency spectrum analysis on the high-frequency signal, preliminarily judging whether a discharge defect exists or not, carrying out Fourier inversion on the low-frequency signal, evaluating a grounding state and an insulation health state of a cable sheath, carrying out Fourier inversion on the high-frequency signal, and carrying out partial discharge fault type analysis in combination with a time domain partial discharge pulse signal and a power frequency current phase; and finally, comprehensively evaluating the operation state of the high-voltage cable by analyzing the grounding current of the sheath and the related parameters of partial discharge. According to the invention, the hardware cost is reduced, the system design and installation complexity is simplified, and the accuracy of partial discharge fault type identification is improved.

The invention relates to the technical field of ground resistance detection, in particular to a single-core cable ground resistance detection method capable of resisting strong power frequency interference. High-frequency signals are injected in a non-contact mode through a coupling type capacitor clamp, background voltage and current signals are collected firstly, and injection frequency far away from power frequency and harmonic waves is selected through Fourier analysis; cancelling background noise by adopting a normalized least mean square adaptive filter to generate an enhanced signal; the signal is down-converted to a base band through digital quadrature demodulation, a Kalman filter estimates the amplitude and the phase in real time, and the state and noise parameters are periodically calibrated through a compressed sensing algorithm; and finally, loop impedance is calculated according to the voltage and current amplitudes and the phase difference to obtain grounding resistance. The method has the advantages of being non-contact, high in safety, strong in anti-interference capability, high in measurement precision and the like, and is suitable for monitoring the grounding state of the cable in a complex electromagnetic environment.

The invention discloses a high-voltage cable operation state on-line monitoring, intelligent early warning and fault positioning system, particularly relates to the technical field of power equipment insulation monitoring, and is used for solving the problems that transient discharge signals generated in the cable insulation degradation process are difficult to effectively capture and accurate fault positioning cannot be realized in the prior art. The method comprises the following steps: collecting transient leakage current signals and traveling wave propagation characteristic parameters, performing phase correlation analysis on leakage current pulses and power frequency voltage to identify discharge types, and performing variational mode decomposition and Hilbert-Huang transform on the signals to respectively extract complexity characteristics and energy distribution characteristics; signal logic conflicts are judged by analyzing similarity and statistical distance among characteristics of a plurality of monitoring points, and collaborative diagnosis is started or traveling wave distance measurement is directly utilized to carry out insulation state evaluation and fault location. And finally, differential early warning levels are generated according to the diagnosis result, and fault line selection and positioning information is output to realize real-time monitoring, intelligent early warning and accurate positioning of the operation state of the high-voltage cable.

The invention discloses an intelligent electromagnetic induction heating method and system for multi-parameter collaborative frequency domain separation, and provides a synchronous parameter acquisition and frequency domain separation processing scheme for solving the problems of temperature detection lag, insufficient frequency domain interference processing and weak dynamic adaptation capability in the prior art. Transient current, voltage and change rate (a first parameter group) of an electromagnetic coil are synchronously acquired, and high-frequency fluctuation (greater than or equal to 10kHz) and low-frequency disturbance (1t, 1t) are converted into low-frequency fluctuation (greater than or equal to 10kHz) by combining environment temperature, cookware materials and user preferences (a second parameter group); 10kHz) is used for frequency spectrum separation. Phase difference features are extracted through band elimination filtering and FFT, heating priorities are corrected in combination with dynamic compensation factors, and a segmented heating curve is generated through time-frequency domain weighted fusion. And the system adjusts PWM parameters in real time, and triggers adaptive protection when detecting that the phase is abnormal or the power frequency exceeds the limit. According to the method, the limitation of single-frequency-band detection is broken through, high-frequency noise suppression and low-frequency disturbance compensation are realized, and accurate temperature control of ferromagnetic / non-ferromagnetic cookware is supported.

The invention discloses a zero-sequence pilot-frequency excitation method for a double-circuit line in an incomplete power failure environment, which comprises the following steps of: applying zero-sequence pilot-frequency signal excitation on a power failure line by using a pilot-frequency power supply as an excitation signal source of a zero-sequence network of the double-circuit line, different-frequency induced current and voltage are measured at secondary sides of a current transformer and a voltage transformer at two sides of the operation line, and different-frequency zero-sequence voltage and different-frequency zero-sequence current in the double-circuit line zero-sequence network are obtained; simultaneously solving a zero-sequence network equation, and calculating mutual impedance between double circuits; performing frequency conversion to obtain the power frequency mutual impedance of the line; and finally, carrying out simulation verification by constructing a non-full-stop double-circuit line zero-sequence mutual inductance impedance measurement system. According to the method, the multi-path coupling caused by the existing power frequency interference method and the accuracy problem caused by the signal measurement error of the zero sequence increment method are solved, the test calculation can be accurately completed under the complex interference working condition, and the safety risk caused by the single-phase reclosing operation is avoided.

The invention relates to the technical field of power frequency resistance real-time monitoring, and provides a traction power supply 27.5 kV cable interval grounding grid power frequency resistance real-time monitoring method and system, and the method comprises the steps: obtaining the temperature distribution data of the surface of a conductor of a grounding grid; acquiring voltage and current response of the grounding grid when the local temperature rise value exceeds a preset reference value to perform frequency domain conversion, and generating a broadband impedance spectroscopy analysis result; aligning earth surface coordinates corresponding to the temperature measurement nodes with underground coordinates corresponding to the impedance measurement points, generating a space correlation grid, generating a temperature rise phase deviation coupling relation matrix, and generating a real-time monitoring result of the power frequency resistance of the grounding grid according to a power frequency impedance correction value in the space correlation grid and the temperature rise phase deviation coupling relation matrix; according to the invention, accurate space matching between the abnormal temperature rise area and the impedance change of the corresponding conductor is realized, the adaptability of a monitoring network to the extension direction and the burial depth change of the conductor is enhanced, and feature signal omission caused by fixed measurement point deployment is avoided.

The invention discloses a high altitude area cable fault early warning and fault positioning method comprising the following steps: monitoring terminals are installed at two ends of a cable line, respectively collect traveling wave signals generated by a cable having a partial discharge source / fault point, carry out on-site data processing on the traveling wave signals, and carry out feature extraction by applying wavelet analysis; and the partial discharge pulse signals are uploaded to a background master station through a wireless or optical fiber communication channel, the background master station draws a partial discharge map according to long-period statistical information such as the amplitude, the number of times and the corresponding power frequency phase of the partial discharge pulse signals, and judgment and fault early warning are carried out on the partial discharge type and the development trend of the cable according to the change condition of the map. According to the invention, the wavelet analysis technology is used to extract the main characteristic quantity of the partial discharge signal, the main characteristic quantity is sent to the background master station through a wireless or optical fiber communication channel, and the arrival time of the wave head of the voltage traveling wave is determined and the fault distance of the power grid is calculated through the wave head identification method of the voltage traveling wave, thereby realizing the fault location of the voltage traveling wave of the power grid. Therefore, the position of the fault point is accurately calculated.

The invention discloses a column type distribution transformer winding abnormity detection system and detection method. The detection system comprises a frequency response detection instrument, a signal coupling assembly, an impedance matching module and a data processing module. The frequency response detection instrument is used for outputting a frequency sweep excitation signal and collecting a winding response signal; the signal coupling assembly is used for isolating power frequency voltage and filtering low-frequency interference; the impedance matching module is used for adjusting output impedance and input impedance to realize matching with electrical characteristics of different windings; and the data processing module is used for constructing an equivalent detection loop model, completing frequency response simulation calculation and carrying out frequency domain analysis and anomaly identification on an actually measured response curve. According to the invention, electrified state diagnosis of distribution transformer winding structure abnormity (such as deformation and loosening) can be realized.

The invention belongs to the field of overvoltage protection, and relates to an overvoltage stabilizing and protecting device which comprises a data acquisition operation module, a control logic module, a display module, an overvoltage protecting assembly and a high-voltage vacuum circuit breaker or an electric isolation handcart structure. The real-time monitoring and protection of the working state of the overvoltage protection assembly are realized; through the arrangement of the high-voltage circuit breaker or the electric isolation handcart, when the overvoltage protection assembly is detected to be abnormal, the connection between the overvoltage protection assembly and the high-voltage bus can be rapidly cut off, so that the system safety is ensured; the device integrates a transient fault recording function and can capture wave map data before and after a power frequency overvoltage fault of the system; the overvoltage protection assembly in the device adopts a geometric center air cooling heat dissipation mode, the fan is quick in starting response, the operating temperature of the overvoltage protection assembly is greatly reduced, the operating time of the overvoltage protection assembly can be effectively prolonged, and the device adopts an integrated modular structural design, so that the operation safety, the maintenance and the management are greatly facilitated.

The invention discloses a power distribution network single-phase earth fault positioning method and system based on zero-sequence admittance comparison, and the method comprises the steps: obtaining zero-sequence voltage and zero-sequence current sampling values at two ends of a protected section, and determining whether to start the detection of single-phase earth fault positioning or not based on the break variable of the zero-sequence voltage; if the detection of the single-phase earth fault positioning is started, the two ends respectively calculate respective power frequency zero sequence voltage phasors and power frequency zero sequence current phasors, and send the phasors to the opposite end; respectively calculating zero-sequence admittance values of the home terminal and the opposite terminal based on the power frequency zero-sequence voltage phasors and the power frequency zero-sequence current phasors of the home terminal and the opposite terminal; and respectively calculating a differential admittance value and a brake admittance value, respectively comparing the differential admittance value with an admittance threshold value and the brake admittance value, and judging whether the protected section is a fault section based on a comparison result. The differential admittance serves as the action amount, the brake admittance serves as the floating threshold, the difference between internal and external faults is amplified, and reliability and sensitivity are effectively improved.

The present application relates to the technical field of inverter control, and relates to a control method for a microinverter and a related device therefor. A specific embodiment of the method comprises: acquiring a maximum power value of a photovoltaic module and a phase angle corresponding to a power grid current in an alternating current power grid, and, on the basis of the maximum power value and the phase angle, determining a target output current; and acquiring a mains frequency current corresponding to an output end of the microinverter, determining a current difference value between the target output current and the mains frequency current, on the basis of the current difference value, determining a target switching frequency corresponding to a plurality of switch tubes in the microinverter, and, by means of the target switching frequency, controlling the turning on and turning off of the plurality of switch tubes in the microinverter, so as to implement the transmission of a current to the alternating current power grid. According to the embodiment, the wave driving control of a microinverter based on a one-stage power conversion topology is achieved, which increases the efficiency and power of the microinverter, reduces the costs of the microinverter, and improves the control effect of the microinverter.

The disclosure provides a method for improving the efficiency of a micro-inverter, and a dual-active-bridge-type micro-inverter. The method including: performing power modulation mode switching of a dual-active-bridge-type micro-inverter, such that the power is bi-directionally transmitted from a direct-current side to an alternating-current side and from the alternating-current side to the direct-current side, thereby reducing an effective value of a secondary side current of a transformer; and according to the modulation mode switching characteristic of the dual-active-bridge-type micro-inverter within a power frequency period, performing hybrid optimization on the turn ratio of a primary side to a secondary side and a transformer leakage inductance of a high-frequency transformer of the dual-active-bridge-type micro-inverter.

The invention discloses a power grid system time service method and system based on a Beidou satellite, and relates to the technical field of power grid system time service, and the method comprises the following steps: obtaining a Beidou satellite signal through a Beidou ground control center, and generating a time frequency reference signal; transmitting the time frequency reference signal to each level of node through a communication network of a power system; and deploying a Beidou time service processing module in local side equipment of the power system, processing the received time frequency reference signal, and generating a system clock signal consistent with the Beidou satellite time reference. According to the invention, triple guarantee is formed through Beidou satellite signals and a dual-channel transmission architecture, i.e., an optical fiber channel and a power line carrier channel; when any transmission channel has a fault, the redundancy switching module automatically selects an optimal path, namely a time delay deviation gt is passed; the threshold triggers switching, and after the Beidou signal is interrupted, a hierarchical timekeeping strategy (atomic clock-adjacent node synchronization-power frequency synchronization) is started.

The invention discloses an intelligent fault recording and traveling wave distance measurement integrated control method and device, and belongs to the technical field of fault positioning, and the method comprises the steps: collecting the power frequency electric quantity data and high-frequency traveling wave data of monitoring points at two sides of a fault line; calculating a first fault distance estimation value based on the power frequency electrical quantity data, and identifying an initial traveling wave head based on the high-frequency traveling wave data to calculate a second fault distance estimation value; defining an evaluation time period, and calculating a signal-to-noise ratio value in the evaluation time period; and according to the signal-to-noise ratio value, determining the contribution degree of the first fault distance estimation value and the second fault distance estimation value in generating final fault positioning distance calculation, and performing comprehensive processing on the first fault distance estimation value and the second fault distance estimation value in combination with the contribution degree to obtain a final fault positioning distance. According to the invention, the accuracy and reliability of fault positioning are improved, and positioning requirements under different fault conditions and signal environments are met.

The invention relates to the technical field of power system relay protection, and discloses a relay protection device mutual inductor adjustment system and method, and the system comprises a system connection initialization module, a data collection reference data generation module, a power frequency background signal offset module, a pilot frequency current injection error calibration module, and a calibration result verification output module. The method comprises the following steps: initializing sampling frequency of a to-be-calibrated mutual inductor and calibration source output precision of a calibration system, collecting amplitude and phase data of real-time power frequency current of the mutual inductor, generating offset current with equal amplitude and opposite directions through power electronic compensation based on reference data, optimizing offset current parameters through a closed-loop adjustment algorithm, and adjusting the offset current parameters through a closed-loop adjustment algorithm. Power frequency background signal offset is completed, pilot frequency calibration parameters are set, a difference value between a mutual inductor pilot frequency output signal and a calibration source standard signal is extracted by adopting a zero pointing technology, an optimal calibration coefficient is automatically calculated, verification of a calibration result is completed, and accuracy and reliability of the calibration result are ensured.

The invention provides a device and method for testing the reliability of a power sensor, and the device comprises a magnetic field generation unit which is used for providing an alternating current for a Helmholtz coil through a power frequency current source, and generating a controllable magnetic field; the electric field generating unit is used for providing a high-voltage direct current or power frequency alternating current power supply for the parallel-plate capacitor through a high-voltage generator to generate a uniform electric field; the tested unit is used for providing a standard excitation signal through a standard source matched with the to-be-tested sensor, simulating an input condition of the to-be-tested sensor under an actual working condition and collecting output data of the to-be-tested sensor; and the control unit is used for setting test parameters, generating a control instruction according to the test parameters and generating a test result according to the output data. According to the device and the method, by simulating a strong magnetic field and a strong electric field environment and combining application of various measured parameters and an automatic control system, the reliability evaluation requirement of the sensor under the actual working condition is fully met.

The invention provides a current transformer dielectric loss anti-interference measurement method based on a variable frequency power supply, and relates to the technical field of power detection, and the method comprises the steps: constructing an excitation channel, collecting a background response signal, recognizing a main interference frequency through combining a frequency tracking algorithm, and dynamically constructing a frequency deviation parameter; generating a pair of non-power-frequency excitation frequency control variable-frequency power supplies to output sine wave excitation signals; excitation voltage and response current signals are synchronously collected to form sampling signals, notch frequency is set according to frequency deviation parameters, main interference is filtered out, and first processing signals are obtained; performing weighting processing by constructing a window function matched with the frequency band characteristic to generate a second processing signal; the complex amplitude and phase information at the target frequency is extracted, the complex impedance is calculated based on the complex current method, the dielectric loss value of the current transformer is finally output, and the anti-interference capability and precision of measurement are effectively improved. According to the invention, the interference in the dielectric loss measurement of the current transformer can be processed, so that the measurement precision is improved.

The invention relates to the technical field of ammeter fault detection, and provides an intelligent ammeter series arc fault detection method, system and device, a medium and equipment, and the method comprises the steps: firstly obtaining an ammeter data set of an intelligent ammeter, which comprises a pre-ammeter voltage, a post-ammeter voltage and a total loop current in a continuous power frequency period, and then carrying out the division through a sliding time window, obtaining a plurality of ammeter data windows; for each window, calculating a voltage difference sequence and a dynamic loss impedance sequence; when the absolute value of the total loop current is smaller than a preset threshold value, determining the current zero-break interval of each power frequency period and the current zero-break time corresponding to the window; determining an arc voltage estimation value according to a voltage difference between non-zero-break intervals in the zero-break interval; and finally, integrating the current zero break time, the arc voltage estimated value and the dynamic loss impedance of each window to judge whether a series arc fault exists, and if so, triggering a protection action. According to the embodiment of the invention, high-reliability identification of the series arc fault is realized.

The invention discloses a construction method and a modulation method of a three-port multi-frequency MMC topology based on bridge arm multiplexing, and relates to the technical field of power electronics. The construction method comprises the steps that sub-modules of a traditional double-bridge-arm MMC are integrated and optimized into a three-bridge-arm structure through a current conversion branch, independent energy interaction of three ports is achieved through an auxiliary bridge arm, multi-frequency operation modes of power frequency, frequency division, direct current and the like are supported at the same time, and therefore the utilization rate of the bridge arm sub-modules is increased, and the energy utilization rate of the MMC is increased. And the overall size and the manufacturing cost of the converter are reduced. Based on three-port multi-frequency coordination control and power balance requirements, a modulation method of the topological structure is provided, a multi-frequency coordination modulation strategy is adopted, frequency offset is performed through an auxiliary bridge arm to reduce cross interference of port frequency, and output waveform quality is improved through multi-objective optimized capacitor voltage balance control. And meanwhile, direct-current side faults are effectively eliminated by means of the auxiliary bridge arm.

The invention discloses an automatic control method and system for transformer substation maintenance, operation and maintenance supervision based on data analysis, and belongs to the technical field of transformer substation maintenance, and the method comprises the steps: collecting multi-source monitoring data of a transformer substation, including voltage, current, transformer oil temperature, partial discharge signals, GIS equipment vibration frequency and insulating oil chromatographic data; performing time sequence processing on the multi-source monitoring data to generate time sequence monitoring data, performing filtering processing on power frequency noise in the time sequence monitoring data by adopting a Daubechies wavelet basis function, and performing feature extraction to obtain time sequence processing data; inputting the time sequence processing data into a pre-constructed long short-term memory network model for fault prediction to obtain an equipment fault probability prediction value; when the equipment fault probability prediction value exceeds a preset threshold value, triggering a multi-stage early warning signal and executing an automatic control operation; and according to the maintenance record data, calculating a fault recovery rate and an operation stability index, and generating a maintenance evaluation report.

The invention belongs to the field of power transmission line parameter measurement, and discloses a live-line testing device and method for mutual inductance line parameters and zero-sequence impedance parameters. The device comprises a double-circuit line simulation module, a pilot frequency excitation module, a power frequency simulation module, a synchronous acquisition module and a signal processing module. The isolation transformer simulates a double-circuit line, the pilot-frequency power supply provides pilot-frequency excitation signals, the measurement unit realizes synchronous acquisition, and the signal processing module performs anti-interference and amplification processing. The method comprises the steps of line simulation wiring, synchronous time synchronization, pilot frequency signal acquisition, parameter calculation and error verification, and pilot frequency parameters are converted into power frequency parameters by using a frequency conversion formula. According to the invention, power frequency interference can be effectively suppressed in a charged environment, high-precision measurement of zero-sequence impedance and mutual inductance parameters of a mutual inductance line is realized by using pilot frequency excitation and Beidou synchronization technologies, the measurement error is remarkably reduced, the safety and reliability are remarkably improved, and powerful technical support is provided for safe and stable operation of a power system.

The invention discloses a bearing electrostatic signal noise reduction method based on VMD-OMP. In order to solve the problem that early fault features are difficult to extract due to the fact that bearing electrostatic signals are easily affected by power frequency interference and environmental noise, a noise reduction technology based on combination of VMD (variational mode decomposition) and OMP (orthogonal matching pursuit) is provided. The method comprises the following steps of: firstly, performing automatic optimization on a modal number and a secondary penalty factor of VMD decomposition by taking an envelope entropy as a fitness function through a grey wolf optimization algorithm to realize adaptive decomposition; and then, screening effective modal components according to the cross correlation coefficient and the kurtosis, determining the optimal sparseness by adopting a saturation value method, respectively reconstructing the components through an OMP algorithm, and finally, directly adding reconstructed signals to obtain a noise reduction result. According to the method, power frequency noise and broadband interference in the bearing electrostatic signal can be effectively suppressed, and the feature definition and the fault recognition capability of the electrostatic signal are improved.

The invention relates to the technical field of power distribution station fault early warning, in particular to a rapid fault early warning method and system for a large-scale power distribution station, and the method comprises the steps: comparing the maximum amplitude difference between electromagnetic wave signals of any two sensors, combining the interference coefficient mean value of the electromagnetic wave signals in all sensors, determining the amplitude deviation, and determining the maximum amplitude difference; the maximum partial discharge signal is screened out by combining the distance between any two sensors; the partial discharge index is determined by analyzing the energy of the maximum partial discharge signal in each frequency interval and the dispersion degree of the maximum amplitude of the electromagnetic wave signals in all the sensors in each target period and combining the proportion of the number of all the target periods in the total number of the power frequency periods. And performing fault early warning on the to-be-tested switch cabinet in the large-scale power distribution station. The invention aims to improve the detection precision of the insulation fault of the switch cabinet in the large-scale power distribution station.

The invention discloses an offshore wind power collecting and sending-out system and method based on a multi-port multi-frequency alternating current and direct current hybrid integrated platform, and belongs to the field of power transmission and distribution of power systems. The system comprises an intermediate-frequency, power-frequency and low-frequency wind power collection subsystem, an offshore integrated platform, a direct-current sending-out submarine cable, a low-frequency sending-out submarine cable, an onshore converter station and an onshore frequency conversion station. The various wind power collection subsystems respectively collect wind turbine generator group outputs with corresponding frequencies and send the wind turbine generator group outputs to the offshore integrated platform; the offshore integrated platform converts intermediate-frequency, power-frequency and partial low-frequency electric energy into direct current and then transmits the direct current to the onshore converter station through the direct-current sending-out submarine cable, and the converter station converts the direct current into power-frequency alternating current; and after being boosted, the other low-frequency electric energy is sent to a land frequency conversion station through a low-frequency sending-out submarine cable to be converted into power-frequency alternating current, so that efficient collection and grid-connected sending-out of multi-frequency wind power resources are realized. According to the invention, the problem that a plurality of independent platforms need to be built in a complex multi-point grid-connected scene in the prior art can be solved.

The invention discloses a power frequency phase adaptive acquisition device, and relates to the technical field of electric power signal measurement, the device acquires electric field data at a gap through an electric field sensor integrated on an edge shell, calculates electric field intensity fluctuation, and generates interference diagnosis information in combination with a preset interference determination threshold value; when the interference diagnosis information shows that effective interference exists, the electric field intensity variable quantity is calculated, a mapping model is established based on a proportionality coefficient obtained through an experiment so as to obtain zero crossing point offset, and the sampling trigger moment of a zero crossing point detection module is corrected; the clock synchronization module calculates a phase difference by taking the corrected trigger moment as a reference, dynamically adjusts a calibration frequency by combining a phase difference threshold value, and outputs a synchronized system clock signal; and the control system takes the synchronized system clock signal as a trigger signal, collects power frequency phase data according to a power frequency period, and stores the power frequency phase data to a database through a transmission unit, thereby realizing high-precision power frequency phase collection.