7 results about "Self impedance" patented technology

This invention discloses a method, apparatus, electronic device, and storage medium for determining node voltages in an electromechanical transient network containing an infinite bus, belonging to the field of power system electromechanical transient simulation technology. The method includes: obtaining the node admittance matrix of the power system to be simulated and the injected current of each grid-connected device except the infinite bus; solving the equivalent impedance matrix based on the node admittance matrix to obtain the self-impedance of the infinite bus and its mutual impedance with each node; calculating the total equivalent voltage drop formed at the infinite bus by each grid-connected device in conjunction with its injected current and corresponding mutual impedance; deriving the injected current of the infinite bus based on the infinite bus voltage phasor, self-impedance, and total voltage drop; and substituting the injected current of the infinite bus and the injected currents of other grid-connected devices into the node admittance matrix to solve the network equations to obtain the voltages of each node. The implementation of this invention can solve the problem of network node voltages deviating from preset standards during transient processes in existing technologies.

The present application relates to the technical field of matcher device, especially to a matcher device suitable for high pressure working environment, which aims at the problem that the existing radio frequency matcher cannot be adapted and optimized for the high pressure environment formed by the injection of sulfur hexafluoride into a sealed tank, is prone to abnormal operation or even stoppage failure under the action of high pressure in the tank, and cannot meet the use requirements of special experimental scenes, and proposes the following technical scheme: a matcher shell is provided with two groups of baffles; two groups of capacitors are arranged between the two groups of baffles, and adjusting mechanisms are arranged at two ends of the capacitors respectively, the adjusting mechanisms are used for adjusting the capacitance value of the capacitors to dynamically adjust the self impedance of the matcher; and a circuit board is installed in the matcher shell. The matcher can be used in high pressure working environment, is safe and convenient, and has good social and economic benefits.

This invention discloses a novel online location method for critical branches in power systems based on impedance short-circuit ratio. The method includes: defining an expression for calculating the impedance short-circuit ratio of any connected device; obtaining a node impedance matrix for calculating the impedance short-circuit ratio of the connected device; taking the self-impedance corresponding to the access node of the connected device in the diagonal elements of the node impedance matrix as its Thevenin equivalent impedance; expressing the change in Thevenin equivalent impedance caused by branch switching using a low-order update formula, and calculating the sensitivity of the Thevenin equivalent impedance to the admittance of each branch; defining the branch influence factor and its constituent critical branch online judgment matrix according to the low-order update formula and sensitivity expression, thereby achieving critical branch location at both the device and system levels. This invention fills the current research gap in the field of critical branch location using impedance short-circuit ratio, and can provide a certain reference for the safe and stable operation of future new power systems. It is simple to implement, highly applicable, and has significant value in engineering design.

The present application relates to line calculation model technical field, especially to a kind of line parameter calculation method and system considering soil resistivity and transmission section, method includes: function for soil resistivity update correction is obtained based on historical measured soil resistivity data fitting;Under the condition that the adjacent line of the line to be measured occurs fault and two lines are three-phase symmetrical line, according to self-impedance back-propagation complex penetration depth to calculate soil resistivity to complete the correction of soil resistivity;Sliding window is set according to set length along line, the average value and standard deviation of each window in measuring point are calculated, and the variation coefficient is calculated, the sliding window method based on variation coefficient is used to determine and determine the soil resistivity section boundary;The representative soil resistivity value of each section area is obtained, and the impedance parameter of the whole line is obtained by linear superposition of each section impedance;The positive sequence impedance and zero sequence impedance of line are calculated using segmented and corrected soil resistivity.

The application discloses a configuration method of a distributed phase modifier. The technical scheme is as follows: determining the minimum value and the change rate of the power factor of each new energy cluster at the side of a collecting station, and comparing the minimum value and the change rate with corresponding judgment thresholds respectively; according to the comparison results, the new energy clusters are divided into two groups, for one group satisfying the threshold requirements in the minimum value and the change rate, using the self-impedance and the equivalent impedance of the power grid as the analysis calculation amount, calculating the upper limit value of the influence of each new energy cluster in the group on the power grid voltage; for the other group, using the judgment threshold of the minimum value of the power factor and the equivalent impedance of the power grid as the analysis calculation amount, calculating the upper limit value of the influence of each new energy cluster in the group on the power grid voltage; solving the equivalent reactance of the power grid access formed by the phase modifier; and according to the equivalent reactance of the power grid access, combining the type of the phase modifier, obtaining the access requirements of the phase modifier. The configuration method can effectively suppress voltage fluctuation.

The application discloses a kind of for comprehensive energy export system transient stability analysis method and system, belong to electric power system transient angle stability technical field, method includes: based on synchronous machine-wind power-infinite system equivalent model, the self-impedance of synchronous machine, mutual impedance and its phase angle surplus are calculated, and then determine its electromagnetic power.Combining rotor motion equation and wind power, iteration is solved after fault power angle and speed;Accordingly, the existence of transient energy is calculated according to the trend of its change with power angle, to determine the critical stability point of power angle constraint and corresponding critical voltage.Finally, the critical point and critical voltage obtained are used as the quantitative index of evaluating transient stability margin, for guiding the safe and stable operation and control decision of the export system containing high proportion of new energy.The application can quickly and accurately evaluate system stability boundary, provide effective analysis tool for preventing cascading failure caused by large-scale new energy off-grid.

This invention discloses a method and system for identifying low-voltage distribution transformer topology based on node mutual impedance characteristics, relating to the field of power supply and distribution technology. The identification method first synchronously collects voltage and current time-series data of the transformer head and each user node; it then constructs and solves a mathematical model based on the principle of circuit superposition to obtain the user node mutual impedance coefficient matrix; it extracts the impedance feature vector of each user node, calculates the difference between self-impedance and mutual impedance, and compares it with a preset judgment threshold based on physical parameters to accurately determine the upstream and downstream relationships and co-connection points between user nodes; finally, it reconstructs the complete tree-like physical topology of the transformer area. This invention utilizes only existing measurement data and does not rely on additional hardware, achieving efficient and accurate automated identification of low-voltage distribution transformer topology, providing reliable support for refined operation and maintenance such as distribution network line loss management and fault location.