18 results about "Short circuit impedance" patented technology

The invention relates to the technical field of power distribution monitoring, and discloses an electrical equipment operation monitoring system based on intelligent control, and the system comprises a grid structure recognition unit which collects a switch contact signal, and determines a real-time power grid topology model; the short-circuit capacity evaluation unit reconstructs a node admittance matrix by using a real-time power grid topology model, and calculates node equivalent short-circuit impedance; the transient feature extraction unit samples a node transient current signal and extracts a high-frequency transient component sequence; a monitoring fixed value follow-up setting unit determines a mapping relation between node equivalent short-circuit impedance and short-circuit capacity, and a monitoring threshold value is corrected in a follow-up mode; according to the system and the method, a physical coupling mechanism of the monitoring constant value and the power grid rigidity is established, sensitivity mismatch caused by grid structure reconstruction is eliminated, and the sensing capacity of the system to the initial degradation of equipment is enhanced. The transient integral energy of the high-frequency transient component sequence is calculated, and an abnormal operation signal is generated when the transient integral energy deviates from a monitoring threshold value.

This application discloses a method and apparatus for optimizing the short-circuit impedance of converter transformers. The method includes: establishing the relationship between the cost of each transformer and its short-circuit impedance, the relationship between the loss discount of each transformer and its short-circuit impedance, and the relationship between the reactive power consumption of the converter valve and its short-circuit impedance; further determining the relationship between the number of reactive power compensation devices and the short-circuit impedance of the transformers, thereby determining the relationship between the cost of the reactive power compensation devices and the short-circuit impedance of the transformers; integrating these relationships to obtain a comprehensive cost function of the system cost with respect to the transformer short-circuit impedance; and determining the target short-circuit impedance value. It is evident that the comprehensive cost function considers the cost of the transformers, the loss discount, and the reactive power compensation devices. Therefore, in the design process of equipment in a high-voltage direct current transmission system, not only the cost of the transformers, but also the cost of losses and reactive power consumption are considered, and the determined target short-circuit impedance value is the most economical design value.

The invention relates to the technical field of transformer equipment, and discloses a transformer short-circuit impedance configuration method, a transformer short-circuit impedance configuration system, transformer short-circuit impedance configuration equipment, a medium and a product. Determining a standard value of the short-circuit impedance of each voltage tap of the to-be-selected transformer by combining the short-circuit impedance value of each voltage tap of the in-operation transformer according to the parallel topological relation between the to-be-selected transformer and the at least one in-operation transformer; therefore, the short-circuit impedance value of each voltage tap of the in-operation transformer is utilized to accurately match the short-circuit impedance of each voltage tap of the to-be-selected transformer, the accuracy of the short-circuit impedance of the new transformer is improved, the synchronous full load of the parallel transformers is ensured, and the capacity waste or overload risk is avoided.

This invention discloses a method, system, equipment, and medium for panoramic identification of short-circuit parameters in distribution networks based on multi-frequency disturbance excitation. It belongs to the field of power system condition monitoring and fault analysis technology. The method includes: designing and generating a composite disturbance signal; injecting the composite disturbance signal into the bus under test of the distribution network through a controllable current source, and acquiring time-domain waveform data of the injected current signal and the bus voltage; performing frequency domain transformation to separate and extract voltage and current phasors in the frequency domain; obtaining short-circuit impedance measurements at each frequency point using a first algorithm; and identifying equivalent circuit parameters using the short-circuit impedance measurements at several characteristic frequency points through a parameter fitting method. Compared to traditional single-frequency measurements that can only acquire single-point data, this method provides more comprehensive panoramic parameter information, accurately reflecting the impedance characteristics of the distribution network at different frequencies, and is suitable for modern distribution networks containing a large number of nonlinear loads and power electronic equipment.

This invention discloses a modeling and current limiting method for grid-type energy storage that considers the short-circuit impedance phase angle. Addressing the issue of existing transient analyses neglecting the short-circuit impedance phase angle, this method establishes a fault transient model under non-metallic short-circuit grounding scenarios, correcting the analysis error caused by traditional transient analyses that only consider voltage drops. Based on this, this invention constructs an adaptive virtual impedance based on voltage and current deviations and proposes a hybrid current limiting strategy for actual fault scenarios, combined with a ring current limiter. This improves the transient modeling theory of grid-type energy storage and provides a reference for enhancing overcurrent limiting capabilities under large disturbances. Hardware-in-the-loop simulation results show that this hybrid current limiting strategy can achieve effective current suppression throughout the entire fault process, laying a solid foundation for the safe operation of power electronic equipment.

The present application relates to the field of transformer fault detection, and relates to a transformer fault detection method based on power operation and maintenance. When a short circuit occurs in a circuit, the short-circuit impedance modulus of each phase of the transformer is obtained, the corrected reactance component is analyzed in combination with the current transformer top oil temperature, the reactance component change rate is calculated in combination with the reactance component relative mutual difference, and whether the transformer winding is deformed is judged. If the winding is deformed, the suspected deformed phase is identified, pulses are injected into the high-voltage side first end and the neutral point respectively, the deformed reflection peaks in the first end reflection waveform and the neutral point reflection waveform are collected and identified, and whether there is a suspected deformed point is determined. If there is a suspected deformed point in a certain suspected deformed phase, whether it is a locatable deformed point is determined based on the occurrence time and amplitude of the deformed reflection peak of each reflection waveform of the phase. The position is determined according to the distance between the suspected deformed point and the first end, the accuracy of the deformed point positioning is improved, the maintenance efficiency of the operation and maintenance personnel is improved, and the maintenance cost is reduced.

This application discloses a method and apparatus for calculating design parameters of identical transformers for multiple converter stations. The method includes: acquiring basic transformer data for the rectifier and inverter sides, and calculating the short-circuit impedance for the rectifier and inverter sides; determining the equivalent inductive voltage drop on the rectifier side and the equivalent inductive voltage drop on the inverter side based on the short-circuit impedance; calculating the ideal no-load voltage of the identical transformers; and calculating the design parameters of the identical transformers based on the ideal no-load voltage and the basic transformer data using the same transformer parameter calculation formula. By calculating the design parameters of identical transformers on the rectifier and inverter sides of the DC transmission system, and then setting identical transformers on the rectifier and inverter sides according to the obtained design parameters, the number of spare converter transformers can be reduced, the duplication of transformer design and testing can be avoided, and equipment investment can be reduced.

This application relates to the field of power system simulation modeling technology, and discloses a method for electromechanical transient equivalent modeling of permanent magnet direct-drive wind farms for weak power grids. The method includes: obtaining the network parameters from each wind turbine to the grid connection point PCC, calculating the equivalent short-circuit impedance amplitude, and setting an impedance boundary threshold; dividing the turbines into multiple groups and determining the normalized impedance weight coefficient of each group; coupling and weighting the inertia, damping, and equivalent impedance of each turbine within the group to obtain the equivalent inertia, equivalent damping, and equivalent impedance of the group, and constructing an electromechanical transient multi-machine equivalent model; obtaining the transient response output of the equivalent model and the detailed model under various disturbance scenarios, and calculating the maximum relative error; if the error does not meet the preset threshold, iteratively adjusting the grouping method or weight mapping relationship until the iteration termination condition is met, and outputting a high-precision equivalent model; this application improves the accuracy of the electromechanical transient equivalent model of wind farms under weak power grid conditions.

A transformer short-circuit impedance three-phase synchronous testing method and system, comprising: synchronously collecting different signals on the high-voltage side of the transformer; dynamically adjusting the center frequency and bandwidth parameters of the Morlet wavelet base function based on the real-time frequency; respectively performing wavelet decomposition on the different signals based on the adjusted Morlet wavelet base function to obtain the complex wavelet coefficient matrix corresponding to the different signals; purifying the complex wavelet coefficient matrix of each signal; selecting an effective calculation interval based on the maximum ridge line area of the modulus matrix of the purified different signals, and solving the optimal estimation value of the short-circuit impedance through the least square method according to the elements of the purified complex wavelet coefficient matrix of the different signals in the effective calculation interval; and correcting the calculated short-circuit impedance value through temperature and frequency. The present application ensures the strict alignment of three-phase data and effectively supports the fault diagnosis based on three-phase unbalance degree.

The application discloses a kind of transformer winding state detection devices, it is related to transformer winding detection technical field.The gantry is provided with short-circuit impedance tester in left side wall, the top of gantry is slidably provided with sliding table by guide rail, electric push rod is installed in the front and back of sliding table, the movable end of two electric push rods is fixed with lifting platform, multiple connecting blocks are slidably arranged on lifting platform, the bottom of lifting platform is fixed with first mounting bracket, the inner side of first mounting bracket is rotatably connected with distance adjusting lever by motor two, multiple helical grooves are formed in distance adjusting lever, wire tube one is fixed in the lower section of connecting block, two chucks are installed in the bottom of wire tube one, lifting platform is connected with single chuck by oil pressure adjusting assembly, cleaning assembly is installed in the two chucks.The application realizes the alignment of different specifications transformer winding connection terminal by distance adjusting lever, helical groove and connecting block, realizes the switching of detection winding and the surface cleaning of connection terminal by setting oil pressure adjusting assembly and cooperating cleaning assembly.

This invention relates to the fields of computer-aided design and power equipment manufacturing technology, and discloses a rule-based configuration and streaming assembly method for three-dimensional models of industrial products. The method includes: generating an assembly logic tree based on voltage level and short-circuit impedance; parsing the logic tree into a sequence of assembly instructions containing geometric topological feature vectors; starting an assembly instruction execution engine; traversing the feature tree structure to extract historical information during the model update phase; and when a reference index becomes invalid due to parameter changes, performing a weighted matching search on candidate geometric surfaces using geometric topological feature vectors to lock in a new assembly reference and complete model assembly. This invention effectively solves the problem of assembly reference loss caused by abrupt changes in topology in transformer parametric design by introducing geometric topological feature vectors as an identity independent of the software's internal indexes, and achieves adaptive reconfiguration of complex insulation components under different voltage levels and capacity requirements.

The present application relates to a kind of transformer rated capacity detection method, comprising: S1 constructs transformer rated capacity detection model;S2 obtains the test sample of transformer nameplate, test sample includes transformer rated capacity, transformer no-load loss, load loss and short-circuit impedance parameter;S3 is input to the transformer rated capacity detection model in test sample;S4: compare whether the capacity value of the transformer rated capacity detection model output is consistent with the rated capacity value of this transformer, when the comparison result is consistent, then identify the output capacity value is real capacity value;When the comparison result is inconsistent, then execute step S5;S5 returns step S2, the capacity value of the transformer rated capacity detection model output is used as new transformer rated capacity value, reacquire transformer no-load loss, load loss and short-circuit impedance parameter, continue to execute transformer rated capacity detection.

The invention relates to the hybrid capacitor bank (A) developed to eliminate the disadvantages arising from the existing capacitor banks used in the "measurement of short circuit impedance and load losses" test, which is one of the routine tests of transformers.

The invention discloses an impedance type selection method for an offshore wind power three-winding transformer, which comprises the following steps of: (1) selecting high-medium short-circuit impedance Zk1-2 of the three-winding transformer according to a standard value, and (2) selecting the high-low impedance Zk1-3 of the three-winding transformer by considering two factors: short-circuit current tolerance level and main transformer relay protection setting requirement, and (4) according to the relationship between the short-circuit current limit value of the high-voltage side of the three-winding transformer and the impedance of the three windings, deducing to obtain the value of medium-low impedance Zk2-3. The method systematically elaborates how to determine the value range of the high-low impedance Zk1-3 according to the short-circuit current level and the relay protection setting requirement, and fills the blank of the three-winding transformer station power side impedance value method in the offshore wind power transmission scene. Meanwhile, the values of the high-medium impedance Zk1-2, the high-low impedance Zk1-3 and the medium-low impedance Zk2-3 are calculated from the theoretical angle, a design basis is provided for offshore wind power engineering equipment type selection, and the method has high universality and applicability in engineering equipment type selection.

This invention provides a method and system for detecting transformer winding deformation based on a combination of short-circuit impedance and frequency response methods, belonging to the field of transformer deformation detection technology. It includes: connecting the transformer winding pair under test to a detection circuit based on the combination of short-circuit impedance and frequency response methods; injecting a sweep frequency signal into the transformer winding pair under test through a signal source in the detection circuit; when the frequency of the sweep frequency signal is in a preset low-frequency band, determining whether the transformer winding pair under test is deformed based on the short-circuit impedance; when the frequency of the sweep frequency signal is in a preset high-frequency band, acquiring the winding response signal corresponding to the sweep frequency signal using the detection circuit; establishing a corresponding frequency response curve using an improved signal analysis method, and determining whether the transformer winding pair under test is deformed based on the frequency response curve; overcoming the limitations of traditional detection methods, improving the convenience, accuracy, and real-time performance of detection, and providing a more efficient and reliable solution for the maintenance and fault diagnosis of power transformers.

This application relates to a method, apparatus, and device for correcting line errors in a transformer load short-circuit device. The method includes: calculating the measured short-circuit impedance percentage based on the measured voltage on the high-voltage side of the transformer and the rated high-voltage side voltage of the transformer; calculating the impedance resistance component based on the measured active power on the high-voltage side of the transformer and the rated capacity of the transformer, and calculating the impedance reactance component based on the measured short-circuit impedance percentage and the impedance resistance component; correcting the impedance resistance component using the line loss of the short-circuit conductor on the low-voltage side to obtain a corrected resistance component; calculating the reduced reactance value on the low-voltage side based on the power factor of the short-circuit conductor on the low-voltage side, and correcting the impedance reactance component to obtain a corrected reactance component; calculating the corrected short-circuit impedance based on the corrected resistance component and the corrected reactance component; correcting the corrected short-circuit impedance to a reference temperature, and outputting the standard short-circuit impedance percentage. This method can improve the detection accuracy of load loss and short-circuit impedance.

The invention provides a parameter design method and device for a double-core symmetrical controllable phase shifter, and relates to the technical field of power grids. According to the method, firstly, key performance indexes such as a phase shifting angle, rated capacity, rated voltage, rated current and a short-circuit impedance range of the controllable phase shifter are determined based on system design requirements and constraint conditions, then accurate calculation is carried out according to the key performance indexes, the rated transformation ratio of a series transformer and a parallel transformer of the controllable phase shifter is determined, and the controllable phase shifter is obtained. The core component parameters such as the rated voltage, the rated current and the rated capacity of each winding are obtained, and the layered parameter design thought of first integration and then component is achieved; the overall performance index of the phase shifter is determined from the global demand of the power system, it is ensured that the design target is highly consistent with the system demand, the problem of disjunction with the overall operation condition possibly caused by direct component design is avoided, the overall performance optimization can be achieved, and the problem that a traditional parameter design method of the controllable phase shifter is unreasonable is solved.

The invention discloses a harmonic environment short-circuit parameter measurement method, system, equipment and medium based on a frequency domain separation technology, and belongs to the technical field of power system measurement and protection, and the method comprises the steps: building a harmonic-containing power system model for parameter configuration, continuously collecting three-phase voltage and current signals, and carrying out the preprocessing; fFT transformation and frequency spectrum correction are carried out on the preprocessed signals; the harmonic pollution degree of voltage and current is evaluated; a harmonic interference comprehensive evaluation model is established; frequency domain transformation is carried out; and calculating the uncertainty of the fundamental wave short-circuit capacity and the measured synthetic standard, establishing a quality control mechanism, verifying the accuracy of a measurement result, and performing synchronous optimization. According to the invention, high-precision and high-reliability measurement of short-circuit parameters in a complex harmonic environment is realized, and the accuracy of safety assessment of a power system is remarkably improved.