42 results about "Three phase short circuit" patented technology

The invention provides a flexible direct-current transmission short-circuit current control strategy multi-objective optimization solving method, which specifically comprises the following steps of: 1, constructing a receiving end fault two-port model, and solving parallel fault transition impedance in a receiving end power grid fault model; step 2, in combination with parallel fault transition impedance, deriving a minimum reactive current reference value constraint required by AC voltage support in a fault period and an active current constraint allowed by DC side energy balance and DC voltage upper limit; and step 3, obtaining the short-circuit current safety domain under the three-phase short-circuit fault by combining the minimum reactive current required for reducing the voltage drop when the short-circuit fault occurs, the active current which can be provided by the receiving-end converter station MMC and the amplitude constraint condition of the short-circuit current output by the receiving-end converter station MMC. According to the invention, adaptive analysis and optimization are carried out on an existing short-circuit current control strategy, and it is ensured that the optimized control strategy not only can reduce unbalanced power accumulation, but also can be used for supporting alternating-current power grid voltage through reserved capacity.

This invention proposes a multi-objective optimization solution method for short-circuit current control strategy in flexible DC transmission, specifically including: Step 1, constructing a two-port model of the receiving-end fault and solving for the parallel fault transition impedance in the receiving-end grid fault model; Step 2, combining the parallel fault transition impedance, deriving the minimum reactive current reference value constraint required to support AC voltage during the fault, and the active current constraint allowed by the DC side energy balance and DC voltage upper limit; Step 3, combining the minimum reactive current required to reduce voltage drop during a short-circuit fault, the active current that the receiving-end converter station MMC can provide, and the short-circuit current amplitude constraint condition output by the receiving-end converter station MMC, obtaining the short-circuit current safety domain under three-phase short-circuit faults. This invention adaptively analyzes and optimizes existing short-circuit current control strategies, ensuring that the optimized control strategy can both reduce unbalanced power accumulation and support AC grid voltage through reserved capacity.

The invention discloses a self-adaptive current quick-break protection method considering a distributed photovoltaic access position, belongs to the field of circuit protection, and solves the problems that a traditional protection method is poor in selectivity and adaptability in a multi-power-supply scene, and the technical scheme comprises the steps: S1, building a three-phase short-circuit fault mathematical model containing a distributed photovoltaic DPV based on a power distribution network topological structure, and building a three-phase short-circuit fault mathematical model; fault occurrence positions are divided into three types of fault scenes according to the DPV access points; s2, for the three types of fault scenes, analyzing the distribution rule of three-phase short-circuit current, and constructing and normalizing a position influence factor Kpos based on the influence of DPV access on the short-circuit current; and S3, based on the position influence factor Kpos, designing a protection criterion containing a position correction item through a setting principle of avoiding the maximum short-circuit current at the tail end of the line in current quick-break protection, and dynamically adjusting an action current setting value of the protection device according to the protection criterion. According to the invention, the protection reliability of the photovoltaic power distribution network is improved.

The invention discloses a power grid data processing method and device for offshore wind power, terminal equipment and a storage medium, and belongs to the field of offshore wind power, and the method comprises the steps: obtaining a topological structure, a thermal power and wind power output curve, line transmission capacity limitation, a target line and a target node of a receiving-end power grid; calculating the static bearing margin of the AC line; performing cascading failure simulation based on the target line to obtain line transmission capacity after the failure, and calculating a cascading failure toughness margin based on the line transmission capacity after the failure; calculating a three-phase short-circuit current for the target node, and calculating a short-circuit capacity adaptation degree based on the three-phase short-circuit current; and carrying out weighted calculation on the static bearing margin, the cascading failure toughness margin and the short-circuit capacity adaptation degree of the alternating-current line to obtain an adaptability evaluation value, and determining the running state of the receiving-end power grid, so that the problem of low safety of an offshore wind power and conventional power generation combined power transmission system in the prior art can be solved.

The invention provides a photovoltaic accessible capacity evaluation method and device considering network construction type energy storage, and relates to the technical field of power system analysis and new energy grid connection. The method comprises the following steps: constructing a power grid model, and constructing a system impedance matrix based on a network topology structure of the power grid model; a Thevenin equivalent model of the network construction type energy storage device is established, after the Thevenin equivalent model is connected to a power grid node, the system impedance matrix is corrected, a corrected equivalent system impedance matrix is obtained, and the power grid node comprises at least one photovoltaic load access node; when a three-phase short-circuit fault occurs in a target node, the short-circuit ratio and the photovoltaic permeability of the target node are calculated based on the corrected equivalent system impedance matrix, and the target node is any node in the power grid nodes; and determining the increased maximum accessible capacity of the target node according to the short-circuit ratio and the photovoltaic permeability of the target node. The transmission efficiency and reliability of the power grid can be improved.

A motor control device of the present application controls a motor using a detected value of a rotation angle of the motor, based on a measurement result of a magnetic pole position of a magnetic pole position sensor, the motor being driven by a three-phase alternating current and being provided with the magnetic pole position sensor that measures the magnetic pole position of a rotor, in which the motor control device sets any one of the three-phase alternating current when the motor is in a three-phase short circuit as an object phase, compares a current peak time rotation angle that indicates the detected value of the rotation angle when a current value of the object phase is a peak value with a reference rotation angle that indicates the rotation angle when a prescribed current waveform of the object phase is a peak value, and corrects the detected value of the rotation angle based on a comparison result.

This document provides systems and methods for protecting a motor magnet during a three-phase short circuit. A system includes power electronics configured to energize a three-phase electric motor using a plurality of switches, and control switching logic configured to transition the three-phase electric motor into a three-phase short-circuit state using the plurality of switches, and to switch between the three-phase short-circuit state and a three-phase open-circuit state based on a transient current of the three-phase electric motor using the plurality of switches. In some embodiments, the transition from the three-phase short-circuit state to the three-phase open-circuit state occurs in response to the transient current exceeding a threshold value.In some embodiments, the transition to a three-phase short-circuit state occurs in response to at least one of the multiple switches being damaged.

Systems and methods for protecting a motor magnet during a three-phase short condition are provided herein. A system includes power electronics configured to provide current to a three-phase electric motor using a plurality of switches, and control circuitry configured to transition the three-phase electric motor to a three-phase short condition using the plurality of switches, and alternate between the three-phase short condition and a three-phase open condition using the plurality of switches based on a transient current of the three-phase electric motor. In some embodiments, transitioning from the three-phase short condition to the three-phase open condition is in response to the transient current exceeding a threshold. In some embodiments, the transition to a three-phase short condition is in response to at least one of the plurality of switches being damaged.

This invention discloses a method and apparatus for three-phase short-circuit transient modeling of a permanent magnet synchronous motor. The method includes: acquiring the parameter values ​​of the motor body, the initial values ​​of the synchronous motor during a short circuit, and the constraints; determining the dq-axis current value based on the motor body parameters, the initial values ​​during the short circuit, and the constraints; and establishing a three-phase short-circuit transient model based on the dq-axis current value. This invention establishes motor equations and electromagnetic torque equations based on the motor body parameters, and derives an analytical transient model of active short circuit by determining the initial conditions during a short circuit. This allows for the acquisition of the dq-axis current and torque at any given time, providing a precise data foundation for realizing active short circuits. Furthermore, the analytical model helps the controller set reasonable compensation and achieve precise adjustment.

The invention provides an auxiliary handcart of a high-voltage switch cabinet, which comprises a handcart body, three moving contacts and three test terminals, and is characterized in that the three moving contacts are mounted at the front end of the handcart body in an insulating manner, and the three moving contacts are used for being in contact with the three static contacts when the handcart body is pushed into the high-voltage switch cabinet; the rear end of the vehicle body is provided with three test terminals in an insulated manner. Pressing wheels are arranged at the bottom of the trolley body and used for opening a lifting curtain for shielding a static contact when the trolley body is pushed into the high-voltage switch cabinet. According to the implementation mode, when insulation is measured, the three moving contacts are connected with the three test terminals through the insulated wires, and after the vehicle body is pushed into the high-voltage switch cabinet, the insulation is measured through the test terminals; during grounding, the three test terminals are detached, the three moving contacts and the grounding device are connected through a three-phase short-circuit grounding wire, and grounding is completed after the vehicle body is pushed into the high-voltage switch cabinet. During electricity testing, the three moving contacts and the three testing terminals are detached, and after the vehicle body is pushed into the high-voltage switch cabinet, electricity testing is completed.

The application discloses a new energy multi-station short-circuit ratio calculation method and system, and a storage medium. The method comprises the following steps: performing network topology analysis on a power grid model I containing an external network model to obtain a total topology node set; forming a node admittance matrix according to the device resistance, the electric reactance parameter and the topology node set of the power grid model I, processing the node admittance matrix to obtain a factor table of the node admittance matrix; calculating self-impedance and mutual impedance of nodes corresponding to new energy stations in a node impedance matrix according to the factor table; obtaining short-circuit currents of each node when three-phase short-circuit faults occur, and calculating short-circuit capacities of each node; obtaining new energy multi-station short-circuit ratios of each node according to the short-circuit capacities, the self-impedance and the mutual impedance; and obtaining new energy multi-station short-circuit ratios according to the short-circuit ratios of each node. The application considers the influence of the external network model and the characteristics of a new energy voltage-controlled power supply on the calculation of new energy multi-station short-circuit ratios, and improves the accuracy of the calculation results.

This invention proposes a method for enhancing the stability of power hardware-in-the-loop systems based on DDPG-RP. First, an equivalent circuit model of the system containing grid fault disturbances is established, its dynamic interaction characteristics are analyzed, and the impedance matching conditions for stable operation are determined. Based on this, a phase-compensated and enhanced repetitive-voltage feedforward composite controller is designed. An upper-level intelligent controller is constructed by combining this with a deep deterministic policy gradient algorithm. These two controllers are deployed in the bottom and upper-level control units, respectively, forming a hierarchical collaborative control architecture for grid fault simulation. A test platform is built based on this architecture. After offline training and online deployment of the deep reinforcement learning controller, a three-phase short-circuit fault condition is simulated using a high-power grid-connected interface device to verify its dynamic response and stability. This invention, relying on hierarchical collaboration and intelligent optimization, effectively solves the problem of traditional control systems struggling to balance stability and performance under complex faults, significantly improving system adaptability and robustness.

The application discloses a kind of multi-loop high-voltage cable fault calculation method, device, electronic equipment and medium.The multi-loop high-voltage cable fault calculation method includes: when the asymmetric ground short circuit of high-voltage cable metal sheath occurs, asymmetric ground short circuit is converted into target symmetric three-phase short circuit by symmetric component method, and the asymmetric ground short circuit includes single-phase ground short circuit and two-phase ground short circuit;Based on the principle of multi-loop high-voltage cable metal sheath circulating current calculation, the target symmetric three-phase short circuit is calculated, the insulation state of high-voltage cable is determined, to calculate the corresponding multi-loop high-voltage cable fault according to the insulation state.This embodiment studies the insulation state of high-voltage cable line, anticipates high-voltage cable insulation state and takes corresponding measures, which is beneficial to the safety and reliability of high-voltage cable transmission line.

Embodiments of the present application provide a kind of rotary variable zero calibration method, device, electronic equipment and storage medium, wherein, method includes: drag motor rotor rotation and control its rotating speed;Control motor stator winding by three-phase alternating current inverter ASC enters three-phase short circuit, when the rotating speed of the motor rotor is greater than rotating speed threshold and the fluctuation state value of the rotating speed is less than fluctuation threshold, the three-phase current value of three-phase alternating current motor is acquired;According to the three-phase current value, the rotary variable zero is obtained;The rotary variable zero is written into read-only memory. Implement the above embodiment, can reduce error, so that the precision of the obtained rotary variable zero is higher.

The invention relates to a concept for discharging a DC-link capacitor on an electrical converter by means of the electric converter. For this purpose, the switching elements of all the half-bridges in the electric converter are used to discharge the DC-link capacitor. To this end, firstly all upper or all lower semiconductor switching elements of the electric converter are closed, and subsequently the complementary semiconductor switching elements are periodically actuated with predetermined pulses. In this way, energy is withdrawn from the DC-link capacitor with each pulse.

A method of mitigating electrical faults includes detecting an electrical fault at a first inverter of an electrical propulsion system having the first inverter and a second inverter; activating a three-phase short at a first three-phase electrical circuitry of the first inverter after detection of the electrical fault at the first inverter; and thereafter generating a torque that counters windmilling of the electrical propulsion system by performing at least one of: activating a three-phase short at a second three-phase electrical circuitry of the second inverter; or applying a stoppage voltage via the second inverter.

Provided in the embodiments of the present application are a rotor and an electric motor. The rotor comprises a rotor core and permanent magnets. The rotor core is provided with a plurality of permanent magnet slot groups in the circumferential direction of the rotor core. Each permanent magnet slot group comprises at least two permanent magnet slots arranged in a V-shape with an opening facing outward. The two permanent magnet slots are symmetrical about a first axis of the rotor. One end of each permanent magnet slot is close to the first axis, and the other end thereof is close to a side wall of the rotor core. The permanent magnets are disposed in the permanent magnet slots. Each permanent magnet comprises a main body portion and permanent magnet end portions arranged at two ends of the main body portion in the direction of width thereof, the thickness of the permanent magnet end portions being greater than the thickness of the main body portion. The direction of width of the permanent magnets is perpendicular to the axial direction of the rotor. In the rotor provided in the embodiments of the present application, the thickness of the permanent magnet end portions of the permanent magnets is greater than the thickness of the main body portions in the middle, thereby improving the demagnetization resistance of the permanent magnets at the permanent magnet end portions, reducing the magnetic reluctance of the permanent magnets, increasing the d-axis inductance, reducing a three-phase short-circuit current and improving the continuous operating capability of the electric motor under fault conditions such as a three-phase short circuit.

The utility model relates to the technical field of underground mining tools, and discloses a coal mine underground electrical switch three-phase short-circuit grounding device which comprises a connector, the bottom end of the connector is provided with internal threads matched with an underground switch bolt, the top end of the connector is in bolt connection with a connecting body, a connecting cavity is arranged in the connecting body, a movable connecting rod is arranged in the connecting cavity, and the connecting rod is connected with the connector. The head of the connecting rod is matched with a lower hexagonal counter bore in the bottom of the connecting cavity, the upper portion of the connecting cavity is in threaded connection with a wire clamping block, and the bottom end of the wire clamping block is provided with an upper hexagonal counter bore matched with the head of the connecting rod. A wiring nose is sleeved on the screw of the connecting rod above the wire clamping block, two wiring block retaining covers are mounted above the wiring nose, and the tail of the screw of the connecting rod is mounted at the end of the insulating rod and is fixed through a pin penetrating bolt.

This invention discloses a HIL (High-Intensity Logic) testing method, apparatus, and system for testing the controller of a T-type three-level circuit in an electric vehicle. The HIL testing method includes: simulating the operating states of the T-type three-level circuit based on the controller's output signal and a circuit simulation model of the T-type three-level circuit; wherein the operating states of the T-type three-level circuit include normal operation, three-phase short circuit, and transistor off state; determining the three-phase terminal voltage values ​​in the circuit simulation model based on the operating states of the T-type three-level circuit; determining the three-phase current values ​​in the motor simulation model based on the three-phase terminal voltage values; and feeding back the three-phase currents from the motor simulation model to the controller based on a digital-to-analog converter. The technical solution of this invention enables simulation testing of the controller of the T-type three-level circuit in an electric vehicle under different operating states, improving the comprehensiveness and reliability of HIL testing.

A fault phase selection method based on a high-frequency break variable comprises the following steps: after a protection element starting criterion is satisfied, extracting three-phase fault component voltage data 2.5 ms before and after a protection installation position starting moment, calculating break variable voltage of each phase at the protection installation position, and then obtaining a phase selection coefficient of each phase and zero-sequence and positive-sequence break variable voltage; grounding judgment, three-phase short circuit judgment and two-phase short circuit judgment are sequentially carried out, and fault phase selection is achieved. The method can quickly and reliably act, only needs to extract data 2.5 ms after a fault to carry out fault identification, and is high in protection speed and sensitivity.

The invention discloses a parameter identification-based equivalent machine modeling method for new energy stations of the same model, and belongs to the technical field of equivalent modeling of new energy power plants. The invention aims to solve the problem that the equivalent mode of reducing the model order by combining single machine aggregation and selection modal analysis cannot be applied in practical engineering due to the fact that internal privacy parameters of each unit cannot be obtained. Three-phase short-circuit faults with different severity degrees are applied to a grid-connected point of a to-be-equalized station through actual field test or simulation, so that internal units of the station generate collective dynamic response, and external port characteristics of the grid-connected point are acquired to obtain dynamic processes of a pre-fault steady state, a fault transient steady state and a fault clearing and recovery stage; and identifying related parameters of the FRT controller based on the external port characteristics to obtain FRT parameters, and taking the identified FRT parameters as corresponding FRT parameters of an equivalent machine to realize equivalence of the FRT controller.

The application discloses a network-configuration type energy storage configuration method and system for short-time power impact, and the method comprises the following steps: acquiring all node information of a target regional power grid, including direct-current feeding nodes, new energy grid-connected nodes and load-side load nodes; sequentially performing N-1 three-phase short-circuit fault simulation on all nodes of the target regional power grid, and determining a fault node set according to frequency response characteristics in a simulation result; clustering the load-side load nodes according to a clustering index and a clustering number to obtain load-side load center nodes; taking the union of the direct-current feeding nodes, the new energy grid-connected nodes and the load-side load center nodes as a candidate configuration node set of the network-configuration type energy storage; solving a network-configuration type energy storage configuration optimization model by using a quantum particle swarm optimization algorithm to obtain a network-configuration type energy storage configuration result; and the network-configuration type energy storage configuration optimization model takes minimizing the sum of network-configuration type energy storage costs of the candidate configuration nodes and safety comprehensive indexes of the fault nodes as a target.

Motor drive device attached to a vehicle with a power machine (1) and a motor (2050) directly coupled to each other, wherein the vehicle comprises a DC power supply device (2002) configured to supply an electric current to the motor (2050) and charged by an output of the motor (2050), wherein the motor drive device comprises: an inverter (2030) configured to convert an electric DC current supplied by the DC power supply device (2002) into an electric AC current, and to convert an electric AC current received from the motor (2050) into an electric DC current;and a control device (2001) configured to control the inverter (2030), wherein the motor (2050) and the inverter (2030) configured to drive the motor (2050) each comprise a first group with a U-phase, a V-phase and a W-phase and a second group with an X-phase, a Y-phase and a Z-phase; wherein the control device (2001) comprises: a fault detection unit configured to determine whether at least the inverter (2030) and / or the DC power supply device (2002) has a fault, in order to determine whether or not current flow from the motor (2050) to the DC power supply device (2002) is blocked;a DC supply state determination unit configured to determine whether or not the DC supply device (2002) is fully charged, in order to determine whether or not current flow from the motor (2050) to the DC supply device (2002) is blocked;and a switching unit configured to select, when determined by the fault detection unit and the DC supply state determination unit that the current flow from the motor (2050) to the DC supply device (2002) is blocked, a control operation performed in the inverter (2030) from an all-phase shutdown and a three-phase short circuit based on a motor rotation speed of the motor (2050), an induced voltage of the motor (2050) and a DC linkage voltage of the motor (2050), wherein in the all-phase shutdown all switching elements (3) of the inverter (2030) are open;and wherein the control device further comprises a three-phase short-circuit processing unit configured to perform control such that, when a reduction amount of the three-phase short-circuit torque is equal to or greater than a threshold value 4 while the inverter (2030) is performing the three-phase short circuit, one of the first group and the second group performs power operation and another of the first group and the second group performs recovery in order to achieve a rise and a fall of the DC current from zero.

The application discloses a voltage sag analysis method based on a 1D V-net deep learning model, which can directly learn voltage sag characteristic information caused by motor starting, transformer switching, single-phase short circuit, two-phase short circuit and three-phase short circuit from original monitoring data, and avoids a tedious manual feature extraction process. Compared with a one-way cyclic network structure formed by RNN, LSTM, GRU and the like, the application can improve voltage sag disturbance type classification accuracy and voltage sag start-stop time positioning accuracy. Compared with a two-way cyclic network structure formed by RNN, LSTM, GRU and the like, the application can guarantee voltage sag disturbance type classification accuracy and voltage sag start-stop time positioning accuracy on the basis of reducing model parameters.

The disclosure relates to a method for detecting the torsional vibration behavior (T) of a drive train (1) of an aircraft, in particular an airplane, wherein the drive train (1) is coupled to a permanent magnet synchronous motor (20) as a drive, characterized by a) at least one triggering of a short circuit (K), in particular at least one 2-phase short circuit (K) and / or at least one symmetrical 3-phase short circuit (K) in the operating (101) permanent magnet synchronous motor (20) to apply at least one induced mechanical excitation (A) of the drive train (1), wherein b) the torsional vibration response (T) of the drive train (1) to the induced mechanical excitation (A), in particular to determine at least one natural frequency (f) and / or a resonance frequency of the drive train (1) is detected with a sensor device (30), in particular in the case of a drive train (1) which is essentially free of a torque load. The disclosure also relates to a corresponding device.

Fail-safe device for an inverter that performs control or driving and electrical power generation by using a synchronous motor (3) in which a permanent magnet is used as a magnetic field magnet, wherein the fail-safe device for the inverter comprises: a three-phase switching circuit having semiconductor switching devices (2) for performing an electrical power conversion in an upper branch and a lower branch; an overvoltage detection circuit (4) that detects an overvoltage by monitoring a DC voltage source voltage of the converter; and a control switching circuit (5) which switches a control method for the semiconductor switching devices (2) between a three-phase PWM control and a three-phase short-circuit control in accordance with an overvoltage determination signal from the overvoltage detection circuit (4) and which comprises: a three-phase PWM control circuit (6), a three-phase short-circuiting control circuit (7), each an AND circuit (8) for each semiconductor switching device (2) of the upper branch, via which the three-phase PWM control circuit (6) is connected to the respective semiconductor switching device (2) of the upper branch of the three-phase circuit and one OR circuit (9) for each semiconductor switching device (2) of the lower branch, via which the three-phase PWM control circuit (6) is connected to the respective semiconductor switching device (2) of the lower branch of the three-phase circuit, wherein the overvoltage detection signal is supplied by the overvoltage detection circuit (4) to the three-phase short-circuiting control circuit (7) as an input signal (EN), and wherein an output signal (7ao) of the three-phase short-circuiting control circuit (7) is supplied to the AND circuits (8) and another output signal (7bo) of the three-phase short-circuiting control circuit (7) is supplied to the OR circuits (9) such that In the case where no overvoltage is detected by the overvoltage detection circuit (4), an output signal (5uo) of the AND circuits (8) and an output signal (5uo*) of the OR circuits (9) perform the three-phase PWM control of the semiconductor switching devices (2) and In the event that an overvoltage is detected by the overvoltage detection circuit (4), the output signal (5uo) of the AND circuits (8) and the output signal (5uo*) of the OR circuits (9) perform the three-phase short-circuiting control of the semiconductor switching devices (2), and wherein, in accordance with an overvoltage detection signal from the overvoltage detection circuit (4), the three-phase short-circuiting control circuit (7) outputs a high-impedance signal or the same signal as an input signal.

The invention relates to the technical field of high-voltage power transmission and phase modifier testing, in particular to a reactive power throwing and step load collaborative testing system for a phase modifier set grid-related test, and the system comprises a power grid simulation device which is used for simulating the basic current supply of an AC power grid and is connected to a PCC bus through a power transmission line impedance; the fault injection device is connected to the PCC bus and used for simulating a three-phase short circuit generated by equipment connected to the PCC bus so as to generate a short circuit signal; the power step device is used for adjusting the step amplitude to generate an amplitude signal; according to the technical scheme provided by the invention, the fault injection device and the power step device are guided by the control module to randomly inject a cooperative abrupt change signal (such as a combination of a three-phase short circuit and a load step) to the PCC bus; and possible and unpredictable concurrent or continuous disturbance working conditions of the phase modifier unit in actual complex power grid operation can be simulated in a high-fidelity manner.

The application discloses a reference current acquisition method and device of a grid-following type converter suitable for a power grid fault condition. The reference current acquisition method of the grid-following type converter comprises the following steps: acquiring a voltage drop acting on a virtual impedance of the converter after a power grid fault; acquiring a modulus value of the virtual impedance; acquiring a phase angle of the updated virtual impedance; and acquiring a reference current of the converter according to the voltage drop acting on the virtual impedance after the power grid fault, the modulus value of the virtual impedance and the phase angle of the virtual impedance. The reference current acquisition method of the grid-following type converter can make the grid-following type converter have the ability to adaptively process different types of faults. For example, when a three-phase short-circuit fault occurs in the power grid, the converter automatically outputs three-phase symmetrical currents to balance and support each-phase voltage. When an asymmetric fault occurs in the power grid, the fault-phase current output by the converter is greater than the non-fault-phase, thereby playing a better voltage support role on the fault-phase.

The utility model provides a drawer type grounding device, which is applied to a feeder cabinet and comprises a drawer body which is installed in a cabinet body in a drawing and pushing manner; the three-phase copper bar is located on one side, in the length direction, of the drawer body, and the three-phase copper bar has a first state in which the three-phase copper bar is connected with the bus end in an inserted mode and a second state in which the three-phase copper bar is separated from the bus end along with pulling and pushing movement of the drawer body; the grounding terminal is electrically connected in the drawer body and is arranged far away from the three-phase copper bar; the three-phase short circuit type grounding wire is fixed inside the drawer body and comprises a three-phase connecting end and a grounding connecting end, the three-phase connecting end is electrically connected with the three-phase copper bar, and the grounding connecting end is electrically connected with the grounding terminal; the contact pins are connected to the side, close to the three-phase copper bars, of the drawer body, the contact pins in the first state are connected with the socket ends in an inserted mode, and the contact pins in the second state are separated from the socket ends. The drawer type grounding device is simple in structure, convenient to manufacture, high in grounding operation stability and good in safety.

The invention discloses a method and a device for predicting transient stability of a power system based on a Densection network. The method comprises the following steps of: constructing a plurality of sample sets covering steady-state operation conditions under different loads by using hyper-Latin sampling; setting a three-phase short-circuit fault for each steady-state point, and obtaining transient data and a transient stability index TSI; extracting voltage, power and the like of a plurality of sampling points as input features and forming a feature matrix; expanding the feature matrix into a three-channel two-dimensional time sequence feature map; training a prediction model by utilizing a DenseNet, Xception and a Denseption network of a full connection layer, wherein the DenseNet, the Xception and the full connection layer are fused with the Denseption network; real-time data is input during online prediction, and after feature conversion, TSI is output through the prediction model to judge the stability. According to the method, feature reuse and multi-scale extraction capabilities are fused through the Densection network, and the accuracy and reliability of transient stability prediction of the power system are remarkably improved in combination with full-connection layer regression output.