29 results about "Phase angle difference" patented technology

The invention discloses a transformer area electric leakage fault diagnosis method and device based on fault recording and a storage medium, and relates to the technical field of electric leakage fault diagnosis. The method comprises the steps of calculating a fundamental wave phase angle difference between a residual current and each phase current in a first analysis window based on event recording data, and calculating a phase angle consistency score based on the fundamental wave phase angle difference; judging whether the corresponding phase is a leakage phase or not according to the phase angle consistency score; on the basis of the instantaneous value of each electrical quantity, generating a statistic sequence in which each electrical quantity in the second analysis window is aggregated according to a fixed time period; according to the statistical magnitude sequence, calculating a mean value transition amount of the residual current, a synchronization parameter of the residual current and the total amount of the three-phase current, and duration of the residual current exceeding a threshold value; and judging the electric leakage type according to the mean value transition amount, the synchronization parameter and the duration time. According to the method, the defect that a traditional amplitude correlation method is easily influenced by sampling deviation is overcome, phase positioning is more stable and accurate, and wiring errors and insulation damage are effectively distinguished.

A kind of single-phase grounding fault single-end impedance ranging method and system of DG-containing distribution line, method includes: input parameter and DG distribution to equipment, when single-phase grounding fault occurs in distribution network, the zero sequence voltage of equipment rises, it is judged that single-phase grounding fault occurs, and fault ranging calculation is started;Using symmetrical component method to obtain the sequence components of voltage and current at bus, DG access, load access and fault point;On the basis of the sequence components of voltage and current at fault point, the phase angle difference between line fault phase voltage and current is obtained, and the fault distance is calculated according to the phase angle difference.The ranging effect of the method of the application is very good, and it has practicality.

The invention discloses an intelligent control method and system for real-time switching of a frequency converter, and relates to the field of real-time switching control of the frequency converter, and the method comprises the steps: analyzing the change slope of a frequency deviation time sequence through linear regression based on the phase angle and frequency value of the current output voltage of the frequency converter; meanwhile, the phase angle difference value variation between adjacent sampling points is calculated; the method comprises the following steps of: establishing a state machine of transfer logic, entering a phase angle monitoring state after the frequency is continuously converged, and generating a switching ready signal after judging that a frequency deviation trend and a phase angle difference trend both meet a stable approaching condition; after switching is completed, the switching stability is analyzed through the fluctuation amplitude of the output current and the change trend of the instantaneous rotating speed change rate, a closed-loop correction mechanism is started when the switching stability is detected to be abnormal, the optimal switching moment of the frequency converter is determined, and it is guaranteed that the motor runs stably before and after switching.

The invention discloses a system strength control method and system for a new energy power system in a disturbance state, and relates to the technical field of new energy power systems, and the method comprises the steps: determining a multi-infeed dynamic system according to a power factor, a phase angle difference and the new energy power system; according to the disturbance factors of the new energy power system and the multi-infeed dynamic system, the corresponding dynamic mode is determined, and the accuracy of the dynamic mode is ensured. Therefore, a corresponding feature function and a feature subsystem are matched based on the dynamic mode; in the characteristic subsystem, a corresponding quantitative index is determined based on the power factor and the phase angle difference, and the system strength of the new energy power system in the disturbance state is presented by the quantitative index, so that quantitative control of the power factor and the phase angle difference is realized, and quantitative expression is performed aiming at the system strength of the new energy power system in the disturbance state; and the system strength control accuracy of the new energy power system in the disturbance state is ensured.

The invention belongs to the technical field of power system measurement and control, and relates to a fundamental wave zero-sequence current detection method based on a time domain CPT theory, which comprises the following steps: obtaining a time domain current signal and a voltage signal based on an actual power grid; based on the time domain current signal and the voltage signal, obtaining a physical quantity based on a CPT theory; the physical quantities based on the CPT theory comprise homologous voltage, active power, reactive power and basic apparent power; calculating the physical quantity based on the CPT theory to obtain a fundamental current effective value, a fundamental current voltage phase angle difference and a fundamental current phase; substituting the physical quantity, the voltage signal, the fundamental current effective value and the fundamental current phase based on the CPT theory into a zero-sequence current calculation formula to obtain fundamental zero-sequence current information; the fundamental wave zero-sequence current information comprises a fundamental wave zero-sequence current instantaneous value and a fundamental wave zero-sequence current effective value and amplitude; therefore, fundamental wave zero-sequence current detection which works stably under the conditions of harmonic distortion and three-phase imbalance is realized.

Systems and methods for transferring a load between power sources may include monitoring voltage waveforms of power sources, in response to a power quality event affecting a first power source, switching a first switch device off to disconnect the load from the first power source, calculating a phase angle difference between the power sources based on the monitored voltage waveforms, selecting one of a first and second algorithms for transferring the load to a second power source based on the phase angle, selectively switching a second switch device using the selected one of the first algorithm and the second algorithm to transfer the load to the second power source. A controller may select the one of the first algorithm and the second algorithm based on the phase angle and a metric of the load transfer associated with the algorithms.

The invention discloses a phase difference comparison-based state evaluation method for a lightning arrester with a series gap in a line. The method comprises the following steps of calculating a phase difference between voltages at the head end and the tail end of the line; collecting the sum of the horizontal spans of the towers of the whole line, and establishing an equation set to solve the phase angle difference of each span; and after the phase angle difference of each gear is obtained simultaneously, the sum of the phase angle difference from the head end to the target tower is subtracted by taking the bus voltage phase of the head end transformer substation as a reference, and the voltage phase of the target tower is obtained. Obtaining the total leakage current of the target tower lightning arrester, measuring the outer surface current by using a power taking ring, and subtracting the outer surface current from the total current to obtain a body current and a phase; and subtracting the target tower voltage phase from the body current phase to obtain a current-voltage phase difference, and carrying out expansion calculation on the phase difference of the same-phase lightning arresters of the whole line. And solving the average value of the phase differences, calculating the deviation value of each lightning arrester, and if negative deviation is abnormal, non-negative normal. The lightning arrester phase acquisition problem is solved, the state is evaluated by transversely comparing the phase difference, and a new thought and an implementation method are provided.

The present application discloses a dual-current-based control method for a grid-connected power factor of a flyback inverter, and a controller. The method comprises: acquiring an working electrical signal of a target power grid; obtaining a first current modulation wave signal; obtaining a second current modulation wave signal; obtaining a waveform of a corrected modulation wave signal; and controlling a flyback inverter to output, to the target power grid or an electric device, a target alternating current corresponding to the waveform of the corrected modulation wave signal. The corrected modulation wave signal, which is generated by using a second half waveform of the first current modulation wave signal and a first half waveform of the second current modulation wave signal, has a signal having a phase and frequency consistent with those of the working electrical signal of the power grid, and also has a signal having a phase angle difference from the working electrical signal of the power grid. By using the corrected modulation wave signal of the present application to control the flyback inverter, the flyback inverter can accurately adjust the power factor during grid connection and the harmonic distortion rate is reduced.

The application provides a voltage phase angle-based vacuum circuit breaker inrush current suppression method and system, relates to the technical field of power system protection, and comprises the following steps: obtaining a voltage signal and historical closing data of a circuit breaker; calculating a voltage phase angle difference value and analyzing historical data to obtain characteristic parameters; inputting the phase angle difference value, a voltage amplitude, a system frequency and the historical characteristic parameters into a double-hidden layer neural network to output an optimal closing time and a protection triggering sequence; when a closing instruction is received, deciding whether to immediately or delay trigger a protection component according to whether it is the optimal time; controlling the circuit breaker body to close after all multi-stage protection components are turned on; and adding actual inrush current data to the historical data to optimize the neural network model and realize inrush current continuous suppression.

The invention discloses a small current grounding system fault line selection method and system based on transient information fusion, and relates to the field of small current grounding system fault detection, and the method comprises the steps: carrying out the signal decomposition and reconstruction through employing a VMD algorithm, and calculating the transient energy of a reconstructed current signal; calculating a transient energy measure according to a transient energy value in a power frequency period; according to the second current decomposition result, the second voltage decomposition result, the first current decomposition result and the fundamental component, the fifth harmonic component and the seventh harmonic component corresponding to the first voltage decomposition result, the sum of admittance phase angle difference coefficients in a power frequency period is calculated, and the transient information fusion criterion measure is further calculated; and determining the fault power transmission line. According to the invention, the reliability of fault line selection criteria can be improved.

This invention discloses a method for on-site calibration of low-voltage smart switches, comprising the following steps: initiating meter search, initiating broadcast time synchronization, acquiring downstream devices through topology identification, synchronously freezing the low-voltage smart switch to be calibrated and each downstream device, transcribing the voltage, current, active power, and reactive power of the previously frozen data, performing voltage gain, current gain, and phase angle difference calibration for each phase, and performing power calibration for each phase after waiting for a freeze interval. Compared with existing technologies, the method disclosed in this invention can expand the applicability of on-site meter calibration and improve the accuracy of on-site meter calibration.

A relay protection parameter self-configuration method, device, program product and medium, relate to the technical field of power system. In the method, three-phase voltage, three-phase current and neutral point voltage of a target generator in a preset time period are obtained; a phase angle difference is determined based on the three-phase voltage and the three-phase current, and a comprehensive state feature vector is constructed based on the phase angle difference and the neutral point voltage; the operating conditions of the target generator are classified to obtain multiple operating modes, and a corresponding health state trajectory cluster is determined according to the comprehensive state feature vector in each operating mode; the geometric characteristics of each health state trajectory cluster are analyzed, and the protection parameters of a relay protection device for protecting the target generator are determined based on each geometric characteristic. The method has the effect of improving the effectiveness of self-configuration protection parameters of the relay protection device.

This invention discloses a method for assessing the condition of surge arresters with series gaps on power lines based on phase difference comparison. The steps are as follows: Calculate the voltage phase difference between the beginning and end of the line; collect the sum of the horizontal spans of all towers along the line, and establish a system of equations to solve for the phase angle difference of each span; after obtaining the phase angle difference of each span, use the voltage phase of the busbar at the beginning substation as a reference, and subtract the sum of the phase angle differences from the beginning to the target tower to obtain the voltage phase of the target tower. Obtain the total leakage current of the surge arrester on the target tower, measure the surface current using a current-taking ring, and subtract this value from the total current to obtain the body current and phase; subtract the voltage phase of the target tower from the phase phase of the body current to obtain the current-voltage phase difference, and extend this to calculate the phase difference of all surge arresters of the same phase along the entire line. Calculate the average phase difference, and calculate the deviation value of each surge arrester; a negative deviation indicates an anomaly, while a non-negative deviation indicates normal operation. This invention solves the problem of obtaining the phase of the surge arrester, and provides a new approach and implementation method for assessing the condition through lateral comparison of phase differences.

The invention provides a distribution network grounding fault positioning method based on zero-sequence harmonic impedance phase information, and the method comprises the following steps: 1, obtaining fault transient zero-sequence current data of a plurality of monitoring points on a power distribution network line after a grounding fault occurs; 2, calculating a zero-sequence harmonic impedance phase angle corresponding to each monitoring point based on the fault transient zero-sequence current data of each monitoring point; 3, for a line section formed by adjacent monitoring points, calculating a zero-sequence harmonic impedance phase angle difference of the monitoring points at the two ends of the section; and step 4, performing fault section judgment according to the zero-sequence harmonic impedance phase angle difference: if the phase angle difference of a certain section is greater than a preset threshold value, judging that the section is a fault section. According to the technical scheme, the zero-sequence harmonic impedance phase angle information of the FTU downstream line is obtained by using the transient zero-sequence current recording data generated by the grounding fault, and then the grounding fault section is judged by comparing the phase angle information of the adjacent FTUs, so that the FTU does not need to be configured with a voltage transformer.

The embodiment of the application discloses a kind of parameter calculation methods under asymmetric short-circuit fault condition. Among them, the method comprises: under symmetric short-circuit fault condition, obtaining the expected current ac component oscillogram of symmetric short-circuit;By expected current ac component oscillogram, the current effective value and the phase angle difference of current voltage of multiple time are measured;Under asymmetric short-circuit fault condition, the voltage phase angle of multiple time is measured;According to current effective value, the phase angle difference of current voltage and voltage phase angle, attenuation coefficient is calculated;According to attenuation coefficient, direct current time constant is calculated;According to current effective value, the phase angle difference of current voltage, voltage phase angle and the direct current time constant determine asymmetric short-circuit current expression, so current expression under asymmetric short-circuit fault condition can be simply and accurately obtained, and the operation amount and error rate are reduced.

The application discloses a voltage sag source positioning method, device and equipment based on sequence components. The application introduces the symmetrical component method into the current real part polarity method, and has different processing methods for different symmetrical faults. For the asymmetrical fault, the application adopts the negative sequence component variation to calculate and determine the position of the voltage sag source. For the symmetrical fault, the application adopts the positive sequence component variation to calculate and determine the position of the voltage sag source. The application makes up for the deficiency of the current real part polarity method in the asymmetrical fault determination, and the judgment method of the application is simple and effective, and does not need too complex data processing. Only the variation of the fault phase fundamental frequency current sequence component and the variation of the phase angle difference of the current voltage sequence component are needed to calculate the current real part for different types of faults, so that the relative position of the voltage sag source is determined according to the peak value polarity of the current real part about time, and the accuracy is higher compared with the traditional current real part polarity method.

Disclosed in the present application are a dual-frequency control method for a power factor during grid connection of a flyback inverter, and a controller. The method comprises: acquiring an operating electrical signal of a power grid; obtaining a first sinusoidal modulation wave signal; obtaining a second sinusoidal modulation wave signal; on the basis of a power factor, determining a phase angle difference and a time difference corresponding to the phase angle difference; obtaining a sinusoidal correction modulation frequency; generating a sinusoidal correction modulation wave signal, the frequency of which is the sinusoidal correction modulation frequency; and by means of the sinusoidal correction modulation wave signal, controlling a flyback inverter to output an alternating current. The power factor is adjusted by means of adjusting the phase difference between a target power grid and a sinusoidal correction modulation wave; moreover, a first sinusoidal modulation wave can operate independently when a power source only has active power, and the sinusoidal correction modulation wave can operate independently when the power source requires reactive power adjustment. The flyback inverter is controlled by means of the sinusoidal correction modulation wave in the present application, such that the flyback inverter can accurately adjust the power factor during grid connection, and a harmonic distortion rate is reduced.

The invention discloses a staged current limiting method and system for improving a stability range, and belongs to the technical field of inverter control. The method comprises the following steps: monitoring a power grid fault state, and obtaining a phase angle difference or fault duration when a fault is removed; a current limiting strategy is applied in stages based on the phase angle difference range, a control strategy based on current limiting power factor optimization is adopted in a first preset range to prolong critical recovery time, and a phase angle switching control strategy is adopted in a second preset range to prevent power angle out-of-step. The system comprises a monitoring module and a control module. According to the method, the problem that a traditional current limiting strategy is difficult to consider stability margin improvement within the critical recovery time and power angle out-of-step after the critical recovery time is exceeded is solved, and the transient stability and the system reliability of the network-forming inverter are improved.

The invention discloses a relay protection parameter self-configuration method and device, a program product and a medium, and relates to the technical field of power systems. The method comprises the following steps: acquiring a three-phase voltage, a three-phase current and a neutral point voltage of a target generator in a preset time period; determining a phase angle difference based on the three-phase voltage and the three-phase current, and constructing a comprehensive state feature vector based on the phase angle difference and the neutral point voltage; classifying the operation conditions of the target generator to obtain a plurality of operation modes, and determining a corresponding health state track cluster according to the comprehensive state feature vector under each operation mode; and analyzing geometric features of each health state track cluster, and determining protection parameters of a relay protection device for protecting the target generator based on each geometric feature. The method has the effect of improving the effectiveness of the self-configuration protection parameters of the relay protection device.

The invention relates to the technical field of electric power systems, in particular to a monitoring method for synchronous grid-connected closing of an electric power system and a related product, and the method comprises the steps: collecting voltage waveforms of a generator side and a power grid side in real time; acquiring system delay time; predicting a future synchronization moment when the phase angle difference reaches a preset target value; calculating an optimal switching-on instruction issuing moment; acquiring an actual instruction issuing moment when a monitoring system synchronizing device issues a closing instruction; comparing the optimal switching-on instruction issuing moment with the actual instruction issuing moment, and if the time error is smaller than a set value, judging that switching-on is performed in the same period; otherwise, non-synchronous closing is determined; according to the method, a theoretical optimal switching-on instruction issuing moment is calculated based on the instantaneous phase angle difference, the slip frequency and the slip angular acceleration, and is compared with an instruction moment actually issued by a field synchronizing device, so that the performance of the existing device is quantitatively evaluated.

The invention provides an insulator surface dirt damping characteristic detection method based on a phase angle difference principle, and relates to the technical field of power equipment insulation state online monitoring and diagnosis. Comprising the following steps: S1, constructing a localized low-interference detection system comprising a voltage follower, arranging a measuring electrode on the surface of an insulator, and combining a low-voltage alternating-current power supply and a sampling resistor to obtain phase angle difference data; s2, power supply voltage and sampling resistor voltage waveforms are collected and converted into rectangular wave pulse signals, and a real-time phase angle difference value is calculated; s3, on the basis of the curve that the phase angle difference changes along with time, identifying saturated damp points of the dirty layer, and extracting saturated damp parameters; s4, analyzing the quantitative influence rule of the influence factors on the saturation damping parameters by changing the influence factors; the method reduces the delay and error possibly introduced by software calculation, improves the real-time performance and original accuracy of phase angle difference data, achieves the objective and automatic recognition of the saturated damp point, and improves the precision of the quantification of the dirty damp state.

The application discloses a transformer area electric leakage fault diagnosis method and device based on fault recording and a storage medium, and relates to the technical field of electric leakage fault diagnosis. The method comprises the following steps: based on event recording data, calculating the fundamental wave phase angle difference between the residual current and each phase current in a first analysis window, and calculating the phase angle consistency score based on the fundamental wave phase angle difference; determining whether the corresponding phase is an electric leakage phase according to the phase angle consistency score; generating a statistical quantity sequence of each electrical quantity aggregated according to a fixed time period in a second analysis window based on the instantaneous value of each electrical quantity; calculating the mean value transition amount of the residual current, the synchronization parameter of the residual current and the total amount of three-phase current, and the duration of the residual current exceeding the threshold value according to the statistical quantity sequence; and judging the electric leakage type according to the mean value transition amount, the synchronization parameter and the duration. The application overcomes the weakness of the traditional amplitude correlation method which is easily affected by sampling deviation, and the phase positioning is more stable and accurate, and the wiring error and insulation damage can be effectively distinguished.

An optical distance calculation device and a method of extending a measurable range are disclosed. The device includes a light source that emits rays selectively modulated at a first modulation frequency and a second modulation frequency. A photonic mixer unit generates and stores a plurality of electrical output signals that respectively correspond to phase offset values applied according to an indirect time-of-flight technique and with respect to the selected modulation frequencies. A signal processing circuit processes a first number of electrical output signals at the first modulation frequency to calculate a first measurement phase angle from a calculated first measurement vector, and processes a second number of electrical output signals at the second modulation frequency to calculate a second measurement phase angle from a calculated second measurement vector. A phase angle difference between the first and second measurement phase angles is then calculated, and a correction value is applied to the phase angle difference to produce an extended range phase angle for calculating a distance.

Waves from cement bond logging with a sonic logging-while-drilling tool (LWD-CBL) are often contaminated with tool waves and may yield biased CBL amplitudes. The disclosed LWD-CBL wave processing corrects the first echo amplitudes of LWD-CBL before calculating the BI. The LWD-CBL wave processing calculates a tool wave amplitude and a phase angle difference as the difference of the phases between the tool waves and casing waves. The tool waves are then used to correct the LWD-CBL casing wave amplitude and remove errors introduced from tool waves. In conjunction with the sets of operations described, the LWD-CBL wave processing also includes array preprocessing operations. Array preprocessing may employ variation of bandpass filtering and frequency-wavenumber (F-K) filtering operations to suppress tool waves.

The invention discloses an SOC in-phase adaptive equalization method and system considering an electric energy quality constraint, and belongs to the technical field of high-voltage direct-hanging energy storage systems. The method comprises the following steps: sampling power grid parameters and SOC values, and sequencing to obtain extreme values; calculating a current amplitude, a modulation signal amplitude and a phase angle difference; setting current and modulation degree limits; calculating the maximum values of the four equalization coefficients and selecting the minimum values; initializing parameters, iteratively optimizing the equilibrium coefficient, and adjusting the coefficient based on THD judgment and difference conditions; and finally, adjusting a modulation signal by using the optimized coefficient to realize SOC equalization. Through multi-constraint cooperation and THD self-adaptive optimization, the problem of grid-connected electric energy quality deterioration of an existing scheme is solved, excessive charging and discharging of the battery and over-modulation of the sub-modules are avoided, the balance speed is maximized while the electric energy quality is guaranteed, and the operation reliability and the capacity utilization rate of the high-voltage direct-hanging energy storage system are improved.

The application relates to a kind of ultra-low frequency insulating medium loss calculation methods based on Nyquist theorem, and the specific steps include: using ultra-low frequency power supply to apply voltage to cable, voltage and current are synchronously sampled in sampling period by data acquisition terminal, and sampling signal is obtained;Utilize fast fourier transform algorithm to filter out other frequencies in sampling signal except specified frequency, and obtain filtered signal;All frequency components higher than Nyquist frequency in filtered signal are filtered out, and filtered frequency domain signal is obtained;Utilize inverse fourier transform to convert filtered frequency domain signal into time domain signal, determine the phase angle difference of voltage and current under time domain signal, and utilize phase angle difference to calculate medium loss value.

The invention discloses a differential protection allowable region depicting method and system based on polar coordinate amplitude-phase constraint. The method comprises the following steps: firstly, constructing a polar coordinate system taking a current amplitude ratio at two ends of a line as a polar radius and a phase angle difference as a polar angle; then, deriving a state function according to a differential protection action criterion, and dynamically depicting a continuous allowable action area of differential protection under polar coordinates in combination with a set sensitivity constraint threshold value; and finally, real-time parameters are calculated and positioned in a polar coordinate graph by monitoring currents at the two ends of the line in real time, a fault interval is accurately judged according to the position relation between the real-time parameters and an allowable area, and protection actions are controlled. According to the method, the problems of discontinuous traditional differential protection boundary and poor adaptability caused by fault current characteristic change under high-proportion new energy access are solved, visual, continuous and adaptable accurate description of the protection area is realized, and the protection reliability is remarkably improved.

The invention discloses an AVC locking method and device based on a bus loop closing scene, terminal equipment and a storage medium, and belongs to the field of electric power systems.The method comprises the steps that when a user triggers loop closing operation of two target buses, a power grid topological graph is obtained; determining a power supply of the target bus; if the power supplies of the target bus are not the same power supply, determining that the target bus is a heterogenous bus, otherwise, acquiring a voltage phasor and a frequency time sequence of the target bus, and calculating a phase angle difference and a Pearson correlation coefficient of the target bus; according to the phase angle difference and the Pearson's correlation coefficient, determining whether the target bus is a heterogenous bus or a homologous bus; and if the target bus is a heterogenous bus, locking AVC of reactive equipment in a transformer substation where the target bus is located. The technical blank of bus loop closing scene recognition in the prior art is filled, and the problem that the prior art depends on manual recognition can be solved through implementation of the bus loop closing scene recognition method and device.

This invention relates to the field of power distribution technology, and discloses a method, system, storage medium, and device for calculating the phase angle difference of synchronous closing. The method includes the following steps: acquiring two voltage signals from both sides of the switching equipment at the same time, detecting and repairing abnormal points; performing IIR mean filtering on the signals; determining whether the signal frequencies are all between 40Hz and 60Hz; performing DC removal processing on the signals; determining whether the effective values ​​of the signals are all greater than 80% of the standard effective value; calculating the signal phase angle difference and outputting the result. This invention is simple and effective. When the sampling frequency of the feeder terminal device is low, the designed algorithm improves the accuracy of the phase angle difference calculation result, thereby more accurately controlling synchronous closing, and has strong engineering practicality.