81 results about "Peak value" patented technology

The invention discloses a high-precision transformer fault detection method and system, relates to the technical field of transformer detection, is used for solving the problems of insensitive fault characterization and delayed diagnosis under a light load condition, and judges whether to enter a load judgment mechanism or not by acquiring input side access voltage information and counting low-load accumulated duration. When entering a load discrimination mechanism, detecting the start-stop behavior of a load branch and the temperature rise trend of a winding, calculating a light load index, identifying a light load state, carrying out region division on an iron core, collecting magnetic flux density data, and calculating iron loss balance characteristics aiming at iron loss deviation which is easy to occur under a light load condition; the insulation degradation coefficient is calculated by fusing the oil temperature peak value and the dielectric loss factor, and the abnormal index is generated with the iron loss balance characteristic, so that the early warning of the early hidden fault of the transformer can be realized in a light load scene in which the traditional temperature rise and current indexes are insensitive, and the operation reliability and maintenance efficiency of the transformer in a power distribution system are improved.

The invention is suitable for the technical field of grounding grid defect evaluation, and provides a transient electromagnetism-based grounding grid corrosion defect evaluation method and system, and the method comprises the steps: placing a sensor of a transient electromagnetic detection device above a to-be-detected region of a grounding grid, injecting a pulse current excitation signal into a conical focusing excitation coil, and carrying out the detection of the to-be-detected region of the grounding grid; acquiring an induced voltage time sequence signal through a receiving coil; extracting at least one characteristic parameter from the induced voltage time sequence signal, wherein the characteristic parameter comprises a signal peak value, peak value time, an attenuation rate or a signal integral quantity; inputting the characteristic parameters into a preset corrosion evaluation model, and performing inversion to obtain a residual thickness value or a corrosion depth value of the grounding grid in the to-be-detected area; generating and outputting a quantitative evaluation result containing the residual thickness value or the corrosion depth value; the method can be implemented in a non-stop state of the grounding grid, and an efficient and reliable decision basis is provided for safe operation and state maintenance of a power system.

The invention relates to the technical field of power supply testing, in particular to a power supply testing system and method. Comprising the following steps: performing power supply demand simulation based on a load transition mechanism: performing deep analysis on a correlation relationship among components of a load by using demand analysis, and performing power supply demand simulation according to a deep analysis result; and constructing a power supply response state set based on the power supply demand simulation result and in combination with the load response characteristics, and carrying out the adaptability test of the power supply behavior through a power supply adaptability clustering algorithm according to the distribution characteristics of the load states under different configurations. According to the method, the instantaneous peak value, the stable power consumption and the load transition characteristics are extracted, the power supply response model is constructed in combination with the load state, and the fitting degree of the real power supply demand of each component is improved; and through a multi-round clustering center iteration verification and adjustment mechanism, it is ensured that the test covers the power supply threshold of all components, and the comprehensiveness and reliability of the power supply test are improved.

The invention discloses a multi-parameter collaborative optimization design method for a modular multilevel converter, and belongs to the technical field of modular multilevel converter design. In order to solve the problem of reasonable design of main parameters of the modular multilevel converter, a mathematical model of the modular multilevel converter is constructed; designing a capacitor voltage fluctuation model, a sub-module capacitor capacitance value model and a fluctuation quantity model, and analyzing the relationship between the capacitor voltage fluctuation and the operation condition and the relationship between the sub-module capacitor capacitance value and the operation condition; determining an upper limit value of the bridge arm inductance based on consideration of a system power operation range, determining a design initial value of the bridge arm inductance based on consideration of ring current suppression, determining a lower limit value of the bridge arm inductance based on consideration of resonance avoidance and fault current rise rate limitation, and obtaining a design range of the bridge arm inductance; adjusting the bridge arm inductance to obtain a design value of the designed bridge arm inductance; and according to the capacitance value of the sub-module capacitor and the design value of the designed bridge arm inductor, analyzing the peak voltage and the peak current of the power device IGBT to determine the parameter selection of the power device.

A method for controlling pulse arc welding involving feeding a welding wire and applying a welding current by repeating a pulse cycle including: a peak rising period of applying a peak rising current increasing from a base current to a peak current; a peak period of applying the peak current; a peak falling period of applying a peak falling current decreasing from the peak current to the base current; and a base period of applying the base current. The feed speed of the welding wire is changed such that it beings to change from a reverse-feeding peak value toward a forward-feeding peak value at a point earlier by a first preceding period than the start of the peak rising period. Then, the feed speed reaches the forward-feeding peak value at a point earlier than an end of the peak rising period, and beings to change from the forward-feeding peak value toward the reverse-feeding peak value at a point earlier by a second preceding period than the start of the peak falling period, and reaches the reverse-feeding peak value at a point earlier than an end of the peak falling period.

The invention discloses a scintillation pulse peak voltage sampling method and device and a computer storage medium, and the method comprises the steps: carrying out the peak holding processing of a scintillation pulse, and obtaining a peak holding signal, the size of the peak holding signal and the peak value of the scintillation pulse meeting a first pre-calibrated mapping relation; generating a reference signal, wherein the reference signal conforms to the prior model; comparing the reference signal with the peak holding signal to obtain time difference information when the reference signal crosses the peak holding signal, the time difference information and the peak holding signal conforming to a second pre-calibrated mapping relation, and the second pre-calibrated mapping relation being associated with the prior model; and according to the time difference information, the first pre-calibrated mapping relation and the second pre-calibrated mapping relation, reversely obtaining the peak voltage of the scintillation pulse. On one hand, the problems existing in existing PP-MVT can be solved, on the other hand, the method can be highly compatible with an existing framework of an MVT method, and sampling and restoring of flash pulse key information are completed.

A start-up method for reducing inrush current to a transformer when closing a switching device. The method includes monitoring a voltage in one of the phases. The method also includes, for each of a sequence of iterations: at a same opening angle relative to a reference angle of the monitored voltage, opening the switching device; at a closing angle relative to the reference angle, which is shifted in relation to the closing angle of all other iterations in the sequence, closing the switching device; and obtaining a peak value of the overall inrush current resulting from the closing. The method also includes selecting for future use with said same opening angle, the closing angle of one of the iterations in which the overall inrush current is relatively low when compared with the other iterations of the sequence.

The invention relates to a power outer loop collaborative optimization virtual synchronous generator transient stability improvement method, and belongs to the technical field of virtual synchronous generator transient stability, and the method comprises the following steps: S1, building a virtual synchronous generator small signal power angle model; s2, performing active transient compensation and capacity constraint of power angle-frequency difference cooperative state feedback; s3, voltage deviation driven adaptive reactive power coefficient and active-reactive power combined current limiting are carried out; and S4, fault current impact suppression of the current-driven virtual impedance. The method can effectively reduce peak values and oscillation time of a power angle and a frequency difference, limit a fault current not to exceed a set upper limit, consider voltage support and active support capabilities, has good stability and robustness, and is suitable for controlling the grid-connected virtual synchronous generator under different short-circuit ratios and various fault working conditions.

The present application provides a method for monitoring a through fault current. The method may involve: detecting a through fault; calculating an electrical stress, peak current, and duration of the through fault; determining two sets of percentage state changes associated with the through fault; assigning a respective set of weights and criticalities to each set of percentage state changes; calculating a mechanical state change based on the first set of percentage state changes and the first set of weights and criticalities; calculating a thermal state change based on the second set of percentage state changes and the second set of weights and criticalities; calculating a cumulative state change based on the mechanical and thermal state changes; and training a machine learning model using the electrical stress, peak current, duration, two sets of percentage state changes, and mechanical, thermal, and cumulative state changes.

The application discloses a kind of relay branch state detection method, device, medium and electric meter of three-phase electric meter, including obtaining the voltage digital signal after superposition of each phase branch of three-phase electric meter relay;According to the voltage digital signal after superposition, the voltage peak value of each phase branch and the timestamp corresponding to the voltage peak value are obtained;According to the voltage peak value and the timestamp and the preset state determination condition, the state result of the three-phase electric meter relay branch is obtained.The application solves the problem that the prior art can only judge the overall on-off state of three-phase power supply, resulting in a single state recognition function.

The invention provides a linearization control method and system for an energy storage system, and mainly provides a single-phase-shift frequency conversion modulation method applied to the linearization control method and system, the single-phase-shift frequency conversion modulation method is applied to a single-stage DAB type AC-DC converter, and the alternating current input voltage vac, the alternating current input current iac and the direct current output voltage Vdc of the single-stage DAB type AC-DC converter are sampled; based on the sampled alternating current input voltage vac, the alternating current input current iac and the direct current output voltage Vdc, a control variable theta is obtained through calculation; on the basis of the obtained control variable theta, at the moment when the leakage inductance peak current iLk has the maximum value, a mapping coefficient c of the leakage inductance peak current at the moment is obtained through a differential extreme value method; based on the obtained control variable theta and the mapping coefficient c, calculating to obtain a phase shift ratio D and a switching frequency fs; d = 1-c theta; fs = fa (c-c2theta); and based on the obtained phase shift ratio D and the switching frequency fs, a driving signal for single phase shift frequency conversion modulation is given.

The application relates to the technical field of electric variable monitoring, in particular to a safe power-on test method, device and system for a power distribution cabinet, which comprises the following steps: acquiring three-phase voltage signals of the power distribution cabinet in a safe power-on test process; analyzing the similarity between the three-phase voltage signals of the power distribution cabinet and the fluctuation degree of each-phase voltage of the power distribution cabinet, obtaining three-phase fluctuation characteristic values of the three-phase voltage signals, constructing a peak value difference rate between any two-phase voltage signals according to the peak value difference degree between the three-phase voltage signals, and then acquiring an electromagnetic interference factor of the three-phase voltage signals; and constructing an each-phase voltage abnormality judgment value according to the electromagnetic interference factor and the deviation degree of each-phase voltage, so as to judge the abnormal operation condition of the power distribution cabinet. The application can improve the safe power-on test precision of the power distribution cabinet.

The invention relates to the technical field of three-phase systems, and provides a three-phase voltage state estimation method and system based on virtual coordinates, and the method comprises the steps: calculating the voltage peak value of each phase for three-phase voltages, and determining that a phase is open if the peak voltage of a certain phase is lower than a threshold value in the three peak voltages; for three-phase voltage, virtual beta-axis voltage is generated through an all-pass filter, actual beta-axis voltage is obtained through Clark transformation, the product of the virtual beta-axis voltage and the actual beta-axis voltage serves as an evaluation function, and a positive sequence and a negative sequence are distinguished according to the positive and negative of the evaluation function. The system state can be accurately and effectively judged under the conditions of three-phase imbalance and voltage distortion, the anti-noise capability and the anti-harmonic interference capability are high, and safe and stable operation of equipment under the abnormal condition is ensured.

The invention relates to the technical field of electric signal processing, in particular to an impedance model construction method and system of a new energy flexible low-frequency sending-out system. The method comprises the following steps: recording real-time timing sequences of voltage and current of a converter bridge arm under different working conditions; extracting a time interval between the voltage peak value and the current peak value, a voltage waveform slope change rate and a current waveform oscillation period, and labeling corresponding working condition labels to form a bridge arm dynamic feature library; and identifying the voltage waveform and the current waveform of the converter bridge arm, and synchronously recording the line resistance and the line reactance between the converter stations. According to the invention, through integration of the bridge arm dynamic features, construction of the bridge arm dynamic feature library and high-frequency correction cooperation, adaptive optimization of bridge arm parameters and construction of the impedance model of high and low frequency bands are realized, so that the matching efficiency of the impedance model is improved.

A method for controlling pulse arc welding involving feeding a welding wire (1) and applying a welding current (Iw) by repeating a pulse cycle including: a peak rising period (Tu) of applying a peak rising current (Iu) increasing from a base current (Ib) to a peak current (Ip); a peak period (Tp) of applying the peak current (Ip); a peak falling period (Tk) of applying a peak falling current (Ik) decreasing from the peak current (Ip) to the base current (Ib); and a base period (Tb) of applying the base current (Ib). The feed speed (Fw) of the welding wire (1) is changed such that it beings to change from a reverse-feeding peak value (Wr) toward a forward-feeding peak value (Ws) at a point earlier by a first preceding period (Ta1r) than the start of the peak rising period (Tu). Then, the feed speed (Fw) reaches the forward-feeding peak value (Ws) at a point earlier than an end of the peak rising period (Tu), and beings to change from the forward-feeding peak value (Ws) toward the reverse-feeding peak value (Wr) at a point earlier by a second preceding period (Ta2r) than the start of the peak falling period (Tk), and reaches the reverse-feeding peak value (Wr) at a point earlier than an end of the peak falling period (Tk).

The invention discloses a method for calibrating the conversion relation between the particle number and the mass concentration, and the method comprises the following steps: for aspheric particles, introducing a voltage correction coefficient through employing the concept of equivalent diameter, and obtaining a calculation formula of the mass concentration of the aspheric particles; in a test environment, the number of voltage pulses of the particulate matter sensor within a period of time is collected, the average value of peak voltage of each pulse is solved, and meanwhile, the PM2.5 mass concentration is collected by using a standard instrument; after the calibration coefficient and the proportionality coefficient are calculated and obtained by combining the mass concentration measured by the standard instrument and the quantity concentration detected by the particulate matter sensor, the calibration coefficient and the proportionality coefficient are substituted into a formula to calculate the mass concentration corresponding to the quantity concentration detected by the particulate matter sensor, and meanwhile, the measurement precision of the particulate matter sensor is guaranteed when the particulate matter concentration changes suddenly.

The present application belongs to the technical field of fault identification, and particularly relates to a low-voltage series arc fault identification method based on multi-frequency electrical quantity amplitude-phase combination. The steps include: each downstream monitoring point real-time monitors the voltage waveform distortion rate of adjacent cycles, and judges whether it is greater than or equal to the set distortion rate threshold; if yes, the fault detection algorithm is started; the voltage data of the downstream monitoring point and the corresponding upstream monitoring point are aligned asynchronously and in phase, differentiated to obtain the differential voltage, low-pass filtered, and the voltage characteristic energy is calculated; the minimum point of the voltage characteristic energy is obtained, the voltage energy peak values in the left and right windows are obtained and the corresponding phases are calculated; the peak threshold and the fault sensitive domain are determined, and the counting accumulation is performed; if the counting accumulation exceeds the counting threshold, it is determined as a fault. The present application can improve the sensitivity, accuracy and anti-interference ability of the power grid side fault detection.

The present invention acquires measurement values of the charge capacity and voltage of a power storage element when the power storage element has been charged from the discharge end state, derives, when the rate at which the voltage changes in accordance with changes in the charge capacity is defined as dV / dQ, the charge capacity dependency of dV / dQ on the basis of the acquired measurement values, identifies, on the basis of the derivation result, the peak position of a peak appearing on a characteristic curve indicating the charge capacity dependence of dV / dQ, and detects, on the basis of the identified peak position, a sign of sudden deterioration of the power storage element.

The invention discloses a ground fault detection method and device and a medium. Relates to the technical field of power system power distribution network detection, and solves the common problem of inaccurate ground fault detection of a power distribution network. According to the invention, the transient abrupt change characteristic of the fault moment is amplified through the zero-current transient increment and the zero-voltage transient increment, and even if the transient signal is weak during high-resistance grounding, the transient signal can be separated through increment operation; the transient change rate of the zero-voltage increment differential data is further amplified through an adjacent point difference value, and the voltage abrupt change characteristic under the high-resistance fault is strengthened; the first characteristic signal and the second characteristic signal convert transient relevance into energy quantification characteristics through product operation of current and voltage transient parameters, and the significance of the high-resistance fault signal is further improved. Whether effective mutation exists or not is judged by combining the zero-current transient increment peak-to-peak value, the zero-voltage increment differential data peak-to-peak value, the first characteristic signal and the second characteristic signal, misjudgment caused by single signal fluctuation is avoided, and the grounding fault detection performance is remarkably improved.

To obtain an excellent welding quality by regularly maintaining a one-pulse period one droplet transfer state even when a welding state varies, in consumable electrode pulse-arc welding.SOLUTION: In a pulse-arc welding control method, in which a welding wire is fed, peak rising currents which rise from a value of base currents to a value of peak currents are distributed in a peak rising period of time, the peak currents are distributed in a peak period of time, peak falling currents, which fall from the value of the peak currents to the value of the base currents, are distributed in a peak falling period of time, the base currents are distributed in a base period of time, and the welding currents Iw are repeatedly distributed in a first pulse period to perform welding, feeding speed Fw of the welding wire is set to a forward feeding value in an initial period of time after arc-start at times of t2-t4, the feeding speed Fw is switched between a forward feeding peak value and a backward feeding peak value in a regular period of time after the initial period ends at the time of t4 and the feeding speed is set to the backward feeding peak value in the base period of times of t7-t8.SELECTED DRAWING: Figure 2

The application discloses an output voltage detection method and system based on an aviation power supply, and relates to the technical field of aviation power supply voltage detection; a differential voltage sensor is connected to the output end of the aviation power supply, a high-frequency suppression capacitor is connected in parallel, a sampling rate of 20-50 times the working frequency is set according to the type of the power supply, analog voltage signals are collected and converted, two-stage filtering is performed on the analog signals, the analog signals are amplified to 0-5V by an instrument amplifier, and then the analog signals are converted into digital voltage sequences by a 16-bit ADC; the effective value, peak value and other parameters of the alternating-current power supply, the average value, ripple coefficient and other parameters of the direct-current power supply are calculated; the characteristic parameters are compared with preset threshold values, and if the characteristic parameters exceed the threshold values, it is determined that an abnormality occurs and relevant information is recorded; the detection results are transmitted to a monitoring terminal through RS485, data is stored locally, and when an abnormality occurs, an output switch quantity is output to an alarm device. The application is adapted to aviation power supply load fluctuation and environmental temperature change, has high detection precision, safe data transmission and storage, can accurately identify an abnormality and give an early warning, and improves the reliability and efficiency of aviation power supply operation and maintenance.

The application discloses a kind of IGBT device class II short-circuit transient current peak determination method and device, it is related to power electronics field, the method includes: in response to determining that IGBT device occurs class II short-circuit, IGBT short-circuit transient equivalent circuit is constructed, wherein, IGBT short-circuit transient equivalent circuit includes first node, second node and third node;The complex frequency domain analysis is carried out to IGBT short-circuit transient equivalent circuit, and the node voltage equation of first node, second node and third node is determined;The maximum value of gate electrode voltage is determined based on node voltage equation;According to the control relationship of gate electrode voltage to collector electrode current and the maximum value of gate electrode voltage, the transient current peak value of the IGBT device is determined.The application of a kind of commutating device IGBT class II short-circuit transient current peak calculation method has certain guiding significance for IGBT short-circuit state analysis, and provides support for the protection of commutating device internal IGBT device.

The application discloses a low-voltage power supply pile management method and system, relates to the technical field of intelligent power supply pile management, and samples through a signal sampling and processing module at a high frequency greater than 50 kHz, and constructs an original current set and a preprocessing set, so that subtle disturbances and nonlinear fluctuation characteristics in a power supply process can be accurately captured, the technical limitation that only 'exceeding the limit can be identified' is broken from the root, and the capacity of discovering abnormal signal rudiment in advance is possessed. The ripple feature extraction module constructed by the system not only identifies the ripple density change in the current, but also fuses information in multiple dimensions such as frequency spectrum energy discreteness and phase jitter intensity, and forms a micro-disturbance feature set. Different from the traditional method of only paying attention to the mean value or the peak value, the system identifies the structural change and the continuity change of the disturbance through multiple angles, greatly enhances the identification capacity of the system to the implicit problem in the complex disturbance scene, and improves the resolution and sensitivity of the electrical behavior identification.

The application discloses a fault current limiter input method based on a voltage drop criterion and belongs to the technical field of power system fault protection, which comprises the following steps: collecting three-phase voltage instantaneous values of a fault current limiter installation point and calculating zero sequence voltage; synchronously calculating real-time voltage amplitude and voltage change rate; comparing the real-time voltage amplitude and the voltage change rate with preset criteria and combining zero sequence voltage auxiliary criteria to determine a ground fault; quickly opening a switch to input a current limiting reactor when the fault occurs; and closing the switch to exit the current limiting reactor after the fault is eliminated. The application adopts a comprehensive design of double main criteria of voltage amplitude and voltage change rate plus zero sequence voltage auxiliary criteria, can accurately distinguish a ground fault from normal fluctuations of a power grid, avoids misjudgment and missed judgment, has a quick sampling response, realizes quick input of current limiting by cooperating with a quick switch, can be self-adaptively adjusted according to actual power grid parameters and operating conditions, can effectively suppress a fault current peak value, prevents power equipment from being damaged, and practically improves the safe and stable operation level of a power system.

The transformer capacity for the actual installed load equipment should be calculated appropriately. [Solution] The electrical equipment design support system comprises an acquisition unit that acquires information used in the design of electrical equipment, and a calculation unit that calculates calculation items from the acquired information. The acquired information includes sample data which is information showing the power consumption by time of day when the load equipment is in operation. The calculation unit comprises a power consumption calculation unit that calculates the power consumption by time of day based on the sample data and a coefficient that shows the correspondence between the power consumption by time of day when the load equipment corresponding to the sample data is in operation and the power consumption by time of day when the actually installed load equipment is in operation, a power peak value calculation unit that calculates the peak value of the calculated power consumption by time of day when the actually installed load equipment is in operation, and a transformer capacity calculation unit that calculates the transformer capacity for the actually installed load equipment based on the calculated peak value of the power consumption by time of day when the actually installed load equipment is in operation.

The invention belongs to the technical field of inverter control, and provides an inverter fault ride-through reactive current instruction amplitude limiting method and system, and the method comprises the steps: obtaining the positive-sequence and negative-sequence components and phase information of a power grid voltage through detecting a three-phase voltage instantaneous value when the power grid is in a fault; calculating a positive sequence capacitive reactive current instruction and a negative sequence inductive reactive current instruction according to national standard requirements; analyzing the relationship between the reactive current instruction and the positive sequence voltage amplitude, the negative sequence voltage amplitude and the negative sequence voltage initial phase to obtain the uniform amplitude and phase of the total reactive current instruction in the coordinate system; and carrying out amplitude limiting processing on the reactive current instruction, so that the maximum value in the three-phase reactive current peak values does not exceed the maximum peak value limit value of the output current of the inverter, and obtaining the amplitude-limited reactive current peak value. According to the invention, when the power grid breaks down, amplitude limiting processing can be effectively carried out on the reactive current instruction provided by the inverter, and the situation that the inverter is shut down due to an over-current fault caused by the fact that the reactive current instruction exceeds the maximum current limit of the inverter is avoided.

A system for performing peak current mitigation in an application programming subsystem (APSS) dynamically performs mitigation based at least in part on a power rail voltage and a leakage current obtained at a start-up time. The voltage and the leakage current obtained at the start-up time are used to estimate a peak current. A mapping generated prior to the start-up time maps the estimated peak current to current limiting levels and specifies different current limiting levels to be performed for different ranges of the estimated peak current. At the start-up time, the mapping is used to map the estimated peak current to a current limiting level to be applied. Where a condition at run time indicates that a peak current is occurring or may occur quickly, the mapped current limit level is applied to mitigate the peak current.

The invention provides a method for identifying inductance parameters in cable armoring current blocking equipment, which comprises the following steps of: calculating the action time of a switching device; according to a preset initial inductance value and the null set, determining the voltage at the two ends of the capacitor and the current flowing through the inductor after the switching device of the inductor branch is closed; taking the maximum value of the absolute values of all the elements as the peak value of the surge current; taking the maximum value of absolute values of all elements as the peak value of the impulse voltage; when the peak value of the surge current is not smaller than the set current safety limit value, updating the inductance value of the inductor and re-determining the voltage and the current at the two ends of the capacitor; when the peak value of the surge current is smaller than a set current safety limit value, determining whether the peak value of the surge voltage is smaller than voltages at two ends of the capacitor; and if yes, outputting the current inductance value as the inductance value of the inductor of the current blocking equipment. According to the method, the safety and the reliability of the cable armoring current blocking equipment under the overvoltage condition are effectively improved, and the parameter determination efficiency and the parameter determination accuracy are improved.