12 results about "Symmetrical components" patented technology

The application discloses a kind of based on currentless sampling area end voltage monitoring and collaborative control method and system, comprising: by parallelly arranged in low-voltage distribution area end voltage monitoring device, real-time acquisition area end three-phase voltage instantaneous signal;According to three-phase voltage instantaneous signal extraction fundamental voltage complex phasor;Fundamental voltage complex phasor is carried out symmetrical component transformation, obtains positive sequence voltage component and negative sequence voltage component;According to positive sequence voltage component and negative sequence voltage component, generate comprehensive state index;According to comprehensive state index, generate target compensation voltage complex phasor including positive sequence control amount and negative sequence compensation amount;According to target compensation voltage complex phasor, by parallelly connected control device that accesses area end, injects compensation current to area end.This application aims at solving prior art in dependence on current transformer leads to installation complex, there is power failure construction risk;Voltage, overvoltage and three-phase unbalance problem scattered management, lack unified processing framework;Voltage monitoring and control are independent of each other, cannot form collaborative closed loop and other problems, realize without dependence on current transformer installation, can unifiedly process various voltage problems, and make voltage monitoring and control form collaborative closed loop.

This invention discloses a novel method and system for actively sensing the operating status of a power distribution system. The method includes: identifying multiple monitoring points in the power distribution system; actively injecting a power frequency signal into the neutral point and simultaneously acquiring the three-phase and zero-sequence electrical quantities at each monitoring point; then decomposing the quantities into positive-sequence, negative-sequence, and composite zero-sequence components using the symmetrical component method; and comparing the composite zero-sequence quantity with the measured zero-sequence quantity to accurately determine whether the monitoring terminal is functioning correctly, thereby identifying reliable diagnostic sections and avoiding misjudgments caused by measurement anomalies. Based on this, the load imbalance is quantified by the ratio of negative-sequence to positive-sequence current at normal monitoring points, providing a direct assessment of the economic efficiency of the power grid operation. Simultaneously, the zero-sequence impedance is calculated using the zero-sequence voltage and current under normal conditions to effectively verify the protection settings of the switching equipment. Finally, a state evaluation equation integrating multiple characteristic quantities is established to output the normal or fault state of the power grid in real time. This method can actively sense the operating status of the power distribution system during normal operation.

This invention discloses a method for identifying abnormal sampled value data in bus current differential protection, belonging to the field of current abnormal sampled value data identification. It includes three symmetrical component scoring systems (positive-sequence, negative-sequence, and zero-sequence components) and one abnormal sampled data analysis system. The symmetrical component scoring system scores the sampled current amplitude of the bus branch based on its transient and steady-state characteristics and outputs corresponding feature values. The abnormal sampled data analysis system makes a final judgment on whether the sampled current value of the bus differential protection is normal or not based on the output of the symmetrical component scoring system. This invention utilizes the symmetrical component characteristics of the bus branch current to identify abnormal sampled data, and has the advantages of simple implementation, fast identification speed, and high reliability.

The application discloses a double-fed wind power converter fault diagnosis method and system based on multi-source data fusion. When the converter detects that an electrical quantity exceeds a threshold value or receives a manual starting instruction of an operation and maintenance personnel, each acquisition module is triggered to work. A preprocessing unit performs interpolation, time axis alignment and denoising processing on the acquired multi-source data, and generates a data set in a unified format. A feature extraction unit extracts fault characteristic quantities by using Fourier algorithm, symmetrical component method, four sampling value method and other methods, and outputs a feature data set. Multiple subsystems are independently diagnosed, and respective preliminary diagnosis results are output. A fusion decision unit substitutes the preliminary results of each subsystem into a preset rule base, performs multi-source data fusion by using a weighted voting method, outputs a final diagnosis conclusion, and outputs the result to a closed loop feedback. The application significantly improves the accuracy and engineering practicability of double-fed wind power converter fault diagnosis by using multi-source data fusion and hierarchical diagnosis, and reduces operation and maintenance costs.

The application belongs to the technical field of new energy grid-connected system transient analysis, and particularly relates to a kind of direct-drive wind power grid-connected system transient overvoltage analysis method under asymmetric fault, comprising: obtaining three-phase asymmetric voltage and current, constructing positive and negative sequence double-synchronous positive and negative sequence dq control model of direct-drive wind power station;Establish the mapping relationship with symmetric component method and determine the positive sequence dynamic reactive current increment and negative sequence current suppression coefficient according to the converter control strategy;Establish the sequence network boundary condition under a variety of asymmetric faults;Equivalent direct-drive wind power station to frequency-dependent controlled sequence impedance source, obtain the equivalent sequence impedance of wind farm;Establish the sequence network equation considering wind power dynamic support;Calculate the current and sequence voltage of fault point and obtain three-phase voltage through symmetric component inverse transformation;Calculate the overvoltage coefficient and establish the quantitative relationship between overvoltage coefficient and negative sequence current suppression coefficient and apply it.The application provides theoretical support for parameter setting and capacity planning of wind power grid-connected system.

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.

The application provides a kind of same-tower double-circuit line optimization design method and system considering system zero sequence current constraint: generating full coupling impedance matrix and admittance matrix representing the coupling relationship of six-phase conductor, and integrating the line model with the system model containing the neutral point grounding branch of main transformer, to build a system-line coupling simulation model;With phase sequence arrangement and transposition strategy as design variables, the phase sequence arrangement and transposition strategy are screened and selected to generate a set of candidate design schemes;Batch simulation is carried out on the candidate design scheme set, the three-phase current data of the high-voltage side of the main transformer is extracted, and the neutral point zero sequence current evaluation value of the main transformer corresponding to each scheme is calculated by using the symmetrical component method;With the minimum zero sequence current evaluation value and construction cost as double objectives, and the zero sequence current safety limit and voltage unbalance limit as constraints, a multi-objective optimization algorithm is used to solve the Pareto optimal solution set, and a recommended design scheme is output.

The application discloses a method for early detection of turn-to-turn short circuit of a stator winding of an induction motor based on a voltage signal, and comprises the following steps: collecting three-phase stator winding voltage signals of an induction motor to be detected during operation; performing time-frequency analysis to obtain time-frequency energy; constructing a cost function, and initializing a time-frequency ridge line of the voltage signal; updating the time-frequency ridge line to realize accurate estimation of the time-frequency ridge line of the voltage signal; calculating three-phase voltage symmetrical components, performing time-varying band-pass filtering, and obtaining fundamental waves of the three-phase symmetrical components; calculating amplitudes of the three-phase symmetrical component fundamental waves, constructing an extended zero-sequence voltage factor, and realizing real-time detection of a turn-to-turn short circuit fault; and constructing a fault phase index to realize identification of a turn-to-turn short circuit phase. The application can effectively detect an early turn-to-turn short circuit fault, improves the accuracy of online detection, reduces the hardware cost of online detection, improves the robustness of online detection under non-stationary conditions, reduces the complexity of data acquisition and signal processing, and improves the practicability of intelligent health management.

The application discloses a transformer anti-short-circuit impact method and system based on winding inter-turn dynamic pre-tightening force self-adaptive adjustment. The method comprises the following steps: dividing the winding into multiple regulation and control sub-zones along the axial direction, collecting the electrical operation parameters and mechanical response parameters of each sub-zone in real time; identifying the short-circuit fault type by using the symmetrical component method, and matching the stress distribution mode in combination with an offline calibration library; and identifying the stiffness and damping state of the winding on line based on the Bouc-Wen nonlinear model. The optimal pre-tightening force command of each sub-zone is calculated by using the sequential quadratic programming algorithm with the maximum system energy dissipation as the target, and the dynamic pre-tightening force is applied to the winding through the hydraulic servo system with an accumulator. The pre-tightening strategy can be adjusted in real time according to the short-circuit working condition and the winding aging state, the winding vibration instability is effectively inhibited, and the anti-short-circuit capability of the transformer is improved.

This invention discloses a method for modeling and topology verification of power compartment disassembly and assembly processes based on a multi-source constraint matrix, relating to the field of special vehicle maintenance and assembly process modeling technology. The method includes: constructing a component connection graph model based on graph theory to describe the assembly structure of the power compartment system; extracting multi-source constraint information from the component connection graph model and fusing it into a multi-source process constraint matrix; generating a candidate set of disassembly and assembly sequences containing multiple potential candidate sequences by initially sorting the disassembly and assembly order of each component in the power compartment system; performing recursive topology verification and closed-loop constraint deadlock detection on the candidate set of disassembly and assembly sequences; and selecting the optimal candidate disassembly and assembly sequence from the detected candidate set. This invention solves the problems in existing technologies regarding the reliance on manual experience for disassembly and assembly sequence planning, lack of unified modeling of structural and spatial constraints, and insufficient handling of closed-loop dependencies and symmetrical components in power compartment disassembly and assembly operations.

An effective grounding image analysis system for distributed power sources and load characteristics capable of reflecting real-time changing system conditions is disclosed. The image analysis system is characterized by comprising: a collection unit for acquiring system condition data; a grounding analysis unit for generating grounding information for loads and distributed power sources using the system condition data; a circuit application unit for applying a symmetrical component circuit considering the characteristics of each type of distributed power source; and an analysis unit for calculating the final fault current and final fault voltage of the power system by applying the principle of superposition to the symmetrical component circuit.