36results about How to "Improve transient stability" patented technology

The invention discloses a direct current control method and system for improving transient stability of a grid-connected converter, and the method comprises the steps: judging whether a power angle out-of-limit-based fault judgment module or a voltage out-of-limit-based fault judgment module has a voltage drop or phase jump fault or not when any one module judges that a power grid has a voltage drop or phase jump fault; processing an angular velocity control signal of a synchronous control link through a direct current port transient energy correction module, and performing temporary storage unbalanced power-oriented lifting and inertia correction-oriented lifting on a direct current voltage reference value; the voltage value of the direct-current port capacitor is compared with a direct-current voltage reference value, and is processed by the steady-state direct-current voltage control module to obtain a direct-current voltage control reference value; the output data of the converter at the common coupling point obtains a synchronous control signal according to a synchronous control link; and based on the synchronous control signal, an internal potential reference value is obtained according to an internal potential control link, and then a converter driving signal is generated. According to the invention, the stability problem of the grid-connected converter when the power grid has a transient fault can be effectively solved.

The invention discloses a coordinated control method and device for a deep fault of a wind power sending end and a storage medium, and belongs to the field of safe operation of a power system. The coordination control method comprises the following steps: when a deep fault occurs at a sending end in a wind power flexible direct sending scene, S1, increasing the q-axis current amplitude of a wind power plant, reducing the d-axis current amplitude of the wind power plant, and increasing the amplitude limiting value of the q-axis current of the MMC sending end to a set value so as to meet the low-voltage fault ride-through requirement of the wind power plant; s2, detecting the voltage recovery condition of the grid-connected point of the wind power plant, and judging whether the fault is cleared or not; if yes, executing S3; if not, returning to execute S1; and S3, during the fault recovery period, adopting a suppression strategy to suppress transient overvoltage, and increasing the d-axis current of the wind power plant until the voltage of the sending end of the MMC is recovered to a steady-state value. And in case of a ride-through fault, the transient stability of the wind power plant and the MMC sending end becomes better, and the synchronization stability of the phase-locked loop is improved.

The invention discloses a coordination control method and device for a shallow fault of a wind power sending end and a storage medium, and belongs to the field of safe operation of a power system. Comprising the following steps: when a sending end has a shallow fault in a wind power flexible direct sending scene, S1, increasing the q-axis current amplitude of a wind power plant so as to improve the voltage of a grid-connected point; the d-axis current amplitude of the wind power plant is reduced, and the amplitude limiting value of the d-axis voltage of the MMC sending end is increased to a set value, so that the synchronous stability of a phase-locked loop is improved, and the low-voltage fault ride-through requirement of the wind power plant is met; s2, detecting the voltage of a grid-connected point of the wind power station, and judging whether the fault is cleared or not; if yes, executing S3; if not, returning to execute S1; and S3, during the fault recovery period, adopting a suppression strategy to suppress transient overvoltage, and increasing the d-axis current of the wind power plant until the voltage of the sending end of the MMC is recovered to a steady-state value. And in case of a ride-through fault, the transient stability of the wind power plant and the MMC sending end becomes better, and the synchronization stability of the phase-locked loop is improved.

The invention discloses a VSG control method based on parameter self-adaption and hybrid energy storage SOC adjustment. From the perspective of improving power grid frequency fluctuation under new energy grid connection, important factors such as an action mechanism of a virtual rotor angular frequency variation and a change rate, influence of rotational inertia and a damping coefficient on VSG power frequency response output characteristics, SOC balance adjustment of hybrid energy storage and the like are comprehensively considered; according to the method, the adaptive control of VSG parameters and the coordinated control of the hybrid energy storage SOC are realized, so that the purposes of reducing the response time and overshoot of VSG power frequency output, reducing the decrease amplitude of the SOC of the energy storage system and reducing the frequency fluctuation of a power grid in a transient process are achieved. Compared with a traditional VSG control method, the dynamic response capability of the VSG can be effectively enhanced, the service life of an energy storage system is prolonged, the transient stability of a power grid is improved, and the method has important guiding significance and engineering application value for design and optimization of a VSG controller.

The invention discloses a method for optimizing the dynamic performance of a ship pulse load power supply system based on virtual capacitance control, and the method can achieve the energy conversion and inertia support of the rotation kinetic energy of a synchronous generator and a DC system capacitor through virtual inertia. A method for calculating a virtual capacitance boundary value under various constraint conditions of considering system stability, dynamic characteristics, parameter coupling and the like is given, and on this basis, according to different functions and energy flow characteristics of a source-side converter and a load-side converter in a power supply system, the virtual capacitance boundary value is calculated; a controllable virtual capacitor control strategy considering both the adjusting capacity and the recovery speed is adopted, and the method effectively improves the transient stability of the system and optimizes the capacitor configuration.

The invention discloses a self-adaptive control method for transient stability of a hybrid synchronous control inverter, relates to the technical field of transient stability control of a new energy power generation system, and aims at a transient instability phenomenon based on the hybrid synchronous control inverter under a serious asymmetric fault, self-adaptively injecting positive sequence current and negative sequence current of the inverter, and improving the transient stability of the hybrid synchronous control inverter. The transient stability of the hybrid synchronous control inverter under the asymmetric fault is improved; according to the method, the balance of the system after a serious asymmetric fault occurs can be ensured, the transient stability of the flexible interconnection equipment is enhanced, the influence of positive and negative sequence current on the transient stability is analyzed based on a phase diagram, and the safe operation of the system is greatly improved by designing a self-adaptive current injection strategy; practical application is facilitated, and stable operation of new energy grid connection is guaranteed.

The invention discloses a VSG self-adaption control method under unbalanced power grid voltage. The method comprises the steps that inertia and damping are introduced into a VSG-based inverter control model; determining the relationship between the instantaneous change rate of the electrical angular frequency, the variable quantity of the electrical angular frequency, the inertia and the damping by combining an active power-frequency control equation; determining a steady-state inertia coefficient and a damping coefficient according to the engineering optimization parameters and the variation range of the oscillation angular frequency, and determining the variation range of the inertia coefficient and the variation range of the damping coefficient; determining a self-adaptive control method of an inertia coefficient and a damping coefficient according to the electrical angular frequency variation and the electrical angular frequency instantaneous change rate of different stages; in combination with balanced current control, active power constant control and reactive power constant control under unbalanced network voltage, three-phase balance of output current is realized, and fluctuation of active power or reactive power is suppressed. According to the invention, the influence of unbalanced power grid voltage is reduced, and the transient stability of VSG control is improved through adaptive parameter adjustment.

The invention provides a parallel power control method for a bidirectional interface converter of an AC / DC hybrid micro-grid, and the method comprises the steps: adding an inertia control link and a capacity distribution link into an active control loop of the parallel bidirectional interface converter; according to the alternating current side frequency deviation and the direct current side voltage deviation of the parallel bidirectional interface converter, an active power transmission reference value of each bidirectional interface converter is calculated through inertia control and capacity allocation links; and the active power transmission reference value of each bidirectional interface converter is sent to a power current control ring to obtain a signal for driving a switch in the three-phase bridge type conversion circuit. Power distribution is realized through inertia control and capacity distribution links, the control convenience and reliability of the parallel bidirectional interface converter are improved, the circulating power of the parallel bidirectional interface converter is solved, the complex calculation of control parameters of the parallel bidirectional interface converter is reduced, the power balance state of the parallel bidirectional interface converter is formed, and the reliability of the parallel bidirectional interface converter is improved. And meanwhile, the dynamic response of alternating-current frequency and direct-current voltage and current is improved.

The invention discloses an inverse time limit current amplitude limiting method and device based on a network construction type converter and a medium. The method comprises the following steps: acquiring a three-phase voltage output by a grid-connected point of the grid-forming converter, acquiring initial reference values of d-axis and q-axis components of output current of the grid-forming converter, and further obtaining a reference value # imgabs0 # of a current vector amplitude; and calculating the difference value delta t between the current moment t and the timing moment # imgabs1 #, updating the maximum over-current value # imgabs2 #, and comparing the reference value # imgabs3 # of the current vector amplitude with the maximum over-current value # imgabs4 # to determine whether to correct the reference value # imgabs5 # of the current vector amplitude. And cyclically monitoring the reference value # imgabs6 # of the current vector amplitude of the network-building type converter until the reference value # imgabs7 # of the current vector amplitude is less than or equal to the per unit value # imgabs8 # of the rated value of the network-building type converter, and stopping amplitude limiting. According to the method, the overcurrent limit value of the converter is improved at the initial stage of GFM touch amplitude limiting, then the overcurrent limit value is reduced to the steady-state amplitude limiting value, and the transient stability margin of the grid-forming converter is improved.

This invention discloses a virtual synchronous low-voltage ride-through control method and system for wind turbines with energy storage coordination. The method includes: real-time acquisition of operating parameters of the wind turbine grid connection point and the energy storage system; determining low-voltage faults based on the effective voltage value of the grid connection point and calculating the voltage drop depth; adaptively updating the virtual inertia and damping coefficient based on the drop depth, and calculating the stator transient flux linkage to generate rotor compensation voltage to suppress overcurrent and electromagnetic torque impact; and performing differential correction based on the updated inertia and damping during the fault recovery phase to suppress active power and frequency oscillations, while simultaneously controlling the energy storage system to output reactive power support and active power support based on voltage and frequency deviations. The energy storage system is a hybrid energy storage system composed of lithium batteries and supercapacitors. This invention adopts a unified virtual synchronous generator control structure, eliminating the need for control mode switching and additional hardware, and effectively suppressing rotor overcurrent and low-frequency oscillations.

The application belongs to the technical field of VSG control, and specifically discloses a self-adaptive virtual resistance control method and system based on power feedback switching, which comprises the following steps: monitoring the state of an electric network in real time, and judging the running state of a control system of a virtual synchronous generator; according to the running state of the control system of the virtual synchronous generator, switching actual active power or virtual active power at a grid-connected point of the virtual synchronous generator as a feedback quantity of an active power control loop of the control system of the virtual synchronous generator, so that the mathematical effect of the virtual resistance in a transient process is equivalent to the effect of a real grid line resistance, and self-adaptive virtual resistance control is completed. The application solves the conflict problem between small signal stability improvement and transient stability deterioration caused by the virtual resistance.

The invention discloses an energy consumption device control method and system suitable for symmetric monopole-bipolar direct current, which are applied to the technical field of direct current control, and the method comprises the steps: obtaining the electrical quantity data of a target direct current system; performing abrupt change analysis on the electrical quantity data, and determining a fault event signal based on an obtained analysis result; based on the fault event signal, determining an energy consumption branch input by the target direct current system; a corresponding energy consumption branch is reconstructed, a reconstruction result is executed, and the voltage of the direct-current bus, the current of the sound pole converter and the temperature of the energy consumption resistor are obtained; processing by utilizing a multivariable decoupling control technology to obtain energy consumption power difference data; and based on the energy consumption power difference data, a cooperative control strategy is generated by adjusting an offshore wind plant in the target direct current system. According to the method provided by the invention, the technical problem that the transient stability of the system is influenced due to control target conflict caused by the fact that the independent action of the traditional energy consumption device is not deeply coordinated with other control structures of the direct current system can be solved.

The present invention provides an analysis method that considers the influence of uncertainty on the dynamic process of the power system, and relates to the field of simulation analysis technology. The method expands the Brownian motion term in the random differential-algebraic equation by the Brownian motion expansion method, and then orderly analyzes the influence of each frequency band in the frequency domain corresponding to the Brownian motion on the transient stability of the system, and finds the frequency band that has the most serious influence on the instability of the power system. The proposed framework has the advantages of not needing to linearize the system, effectively retaining the nonlinearity of the system, and being close to engineering applications, and can project the uncertainty of continuous random excitation over the entire simulation time to the start time of the simulation, reducing the complexity of the simulation calculation, and the obtained analysis results can provide a basis for improving the transient stability of the system.

The application discloses a novel three-stage operational amplifier indirect frequency compensation circuit and belongs to the electronic circuit field. A , a second resistor R B , a first capacitor C C1 , a second capacitor C C2 , NMOS tubes MN1-MN8 and PMOS tubes MP1-PMOS tubes MP6; the NMOS tubes MN1-MN5 and the PMOS tubes MP1-PMOS tubes MP2 are a first gain stage of an operational amplifier; the NMOS tubes MN6-MN7 and the PMOS tubes MP3-PMOS tubes MP5 are a second gain stage of the operational amplifier; the NMOS tube MN8 and the PMOS tube MP6 are a third gain stage; the second resistor R B and the first capacitor C C1 , the first resistor R A and the second capacitor C C2 are an indirect frequency compensation network. The application can greatly improve the loop phase margin and the circuit transient stability under the condition of using a smaller compensation capacitor by generating a zero point located in the left half plane to offset a sub-pole in the operational amplifier loop.

The invention discloses a method, a system, equipment and a medium for synchronous control of hybrid networking, and belongs to the technical field of transient stability control. The method comprises the following steps: determining an output duty ratio component Dabc of a network controller in the hybrid network, and determining an output duty ratio component delta Dabc of a q-axis voltage controller in the hybrid network; performing superposition processing on the Dabc and the delta Dabc to obtain the duty ratio dac of the fan converter in the hybrid network; based on the dabc, calculating to obtain voltage positive and negative sequence components to be injected into the q-axis voltage controller; performing synchronous control on the hybrid network construction according to the voltage positive and negative sequence components; wherein the fan converter is connected into a power grid through an L filter to form a grid construction controller, and a q-axis voltage controller is additionally arranged in the fan converter to form a hybrid grid construction. According to the invention, the transient stability of the power grid is improved by performing synchronous control on the hybrid network construction.

The invention discloses a system control method based on synchronization stability analysis of a grid-connected inverter system, and the method comprises the steps: judging whether the grid-connected point voltage of a three-phase grid-connected inverter is greater than a voltage judgment threshold value or not, judging whether the frequency change of a phase-locked loop is smaller than a frequency change threshold value or not if the grid-connected point voltage is greater than the voltage judgment threshold value, and if the frequency change is smaller than the frequency change threshold value, enabling the system to work in a first working condition; if the grid-connected point voltage of the three-phase grid-connected inverter is smaller than the voltage judgment threshold value, the size relation between the frequency change of the phase-locked loop and the frequency change threshold value is judged again, and if the frequency change of the phase-locked loop is smaller than the frequency change threshold value, the system works in the second working condition; otherwise, the system works in a third working condition; integral parameters of the phase-locked loop are correspondingly adjusted according to different working conditions. According to the grid-connected stability analysis and control method of the grid-connected inverter system, the control parameters can be adaptively adjusted according to the real-time condition of the system, and the transient stability of the system when the voltage of the power grid drops is improved.

The invention relates to a method for improving transient stability of a network-building type converter based on voltage amplitude regulation, which comprises the following steps of: simplifying a network-building type converter system model; obtaining three-phase active power from the voltage of the network-constructing converter to the voltage of the power grid and a droop relation between the active power and the frequency; based on the three-phase active power, drawing a relation curve between the active power and the phase angle difference between the grid-forming converter and the power grid, obtaining the active power conversion condition of the grid-forming converter, and determining the condition and balance point of the grid-forming converter for maintaining the transient stability according to the active power conversion condition; and when transient instability of the network-forming converter occurs, according to the conditions, adjusting the voltage and the line resistance of the network-forming converter to reach a new balance point, improving the transient stability of the network-forming converter, and keeping the voltage of the network-forming converter to be greater than the voltage amplitude of the network-forming converter.

The invention discloses a control method and device of an inverter, electronic equipment and a medium, and relates to the field of inverter control, when a power grid voltage drop condition exists in a power system connected with the inverter, given parameters input into a control loop of the inverter are adjusted according to different fault levels caused by the power grid voltage drop; meanwhile, whether feedforward compensation needs to be carried out on a control loop of the inverter or not is judged according to whether the inverter is overloaded or not, and finally operation of the inverter is controlled based on the determined given parameters and the feedforward compensation amount. In the control process of the inverter, if the power system breaks down and / or the load of the inverter is overloaded, the control parameters can be adjusted in time according to the change condition of the voltage of the power grid and the load state of the inverter so as to control the inverter to be always kept in a stable operation state; therefore, the operation of the inverter is prevented from being influenced by abnormal conditions such as power grid voltage drop and load switching, and the transient stability of the grid-connected inverter is improved.

The utility model discloses a hybrid controllable series compensation device, which relates to the field of flexible alternating current power transmission of a power system and comprises fixed series capacitors C, CC and CTCSC, a reactor LTCSC and two anti-parallel thyristor valves. The fixed series capacitor C is a fixed series compensation device for a phase a and a phase b of the power transmission line; the reactor LTCSC and the two thyristor valves are connected in series to form a thyristor control reactor branch; the thyristor control reactor branch is connected with a fixed series capacitor CTCSC in parallel to form a single-phase controllable series compensation system; the fixed series capacitor CC and the single-phase controllable series compensation system are connected in series to serve as a compensation device of a c-phase power transmission line. According to the utility model, a control strategy of an active damping controller based on a synchronous voltage reversal control method is adopted to control the device, so that suppression of subsynchronous resonance is realized, and safe and stable operation of a power transmission line is ensured.

This invention relates to the field of grid converter control technology, and more particularly to an adaptive hybrid synchronization control method for a grid converter, comprising an active power outer loop controller, a hybrid synchronization control link, and an adaptive link; the system control angular frequency in the active power outer loop controller serves as the system control angular frequency input to the adaptive link; the adaptive angular frequency adjustment output by the hybrid synchronization control link is connected to the active power outer loop angular frequency of the active power outer loop controller; and the adaptive link outputs the hybrid synchronization adaptive gain of the hybrid synchronization control link. This invention can adaptively adjust the equivalent damping of the system according to the system state, ensuring a sufficiently fast power step response during normal system operation, and providing sufficient equivalent damping to ensure transient stability when the system enters a fault state.

The application discloses a kind of based on network type VSC current limiting strategy's transient stability control and analysis method, its steps include:1, in voltage control loop using anti-integrator saturation module;2, introduce current saturation angle and determine its optimum value;3, based on the introduction current saturation angle to improve VSC current limiting module;4, based on current limiting module and current saturation angle, using phase diagram to analyze system transient stability.The application introduces current saturation angle to carry out transient stability control, can effectively promote the transient stability of the system formed by network type VSC and infinite grid, and the transient stability of network type VSC is qualitatively analyzed by phase diagram.

This invention discloses a transient stability control method for a doubly-fed induction generator (DFIG) wind turbine grid-connected system under asymmetrical grid faults. By calculating the positive and negative sequence active and reactive currents output by the DFIG wind turbine grid-connected system during asymmetrical grid faults, and optimizing these outputs, transient stability control of the DFIG wind turbine grid-connected system under asymmetrical grid faults is achieved. This method considers the requirements of grid guidelines and, without adding hardware, ensures that the stable equilibrium point of the system's positive and negative sequence equivalent power angles coincides with the initial operating point during the quasi-steady state. This minimizes the unbalanced transient energy accumulated by the system during the quasi-steady state and reduces the probability of transient instability.

The invention discloses a transient stability constraint optimal power flow model construction method based on wind power uncertainty. The method comprises the following steps: step 1, establishing an uncertainty output model of wind power generation according to an uncertainty standard; step 2, constructing transient stability constraints by using a single-machine equivalent SME method; 3, describing inequality constraints and transient stability constraints based on a joint opportunity constraint (JCC) theory, and constructing a transient stability constraint optimal power flow TSCOPF model; 4, converting the joint opportunity constraint into a deterministic sample constraint by adopting sample average approximation SAA; and 5, solving the constructed TSCOPF model by using a collective decision optimization (CDO) algorithm. The invention discloses a transient stability constraint optimal power flow model construction method based on wind power generation uncertainty, which is suitable for a power system accessed by wind power generation and has important significance for improving the stable operation of the power system.

The invention relates to the technical field of new energy power generation of power distribution systems in mountainous areas, and discloses a stability control method, system, equipment and medium for a grid-forming type brushless doubly-fed fan, and the method comprises the steps: firstly constructing a BDFIG mathematical model, deducing an active power expression under a fault condition, and determining the quantitative relation between the power grid voltage fault depth and the system stability; secondly, an LESO improvement strategy is introduced into a virtual synchronous control (VSynC) loop, power angle oscillation disturbance is observed and compensated in real time, and the transient stability of the BDFIG grid-connected system is remarkably improved.

The invention discloses a distributed phase modifier additional excitation system control method considering a PSO-GWO-PID algorithm, and the method comprises the following steps: carrying out the preprocessing of a PID parameter of a feed-forward link of a grid-connected bus voltage through the combination of a particle swarm algorithm, and obtaining an optimal PID controller parameter of the feed-forward link based on a gray wolf algorithm; obtaining first data of the phase modifier, evaluating the transient stability level of the phase modifier in combination with a Lyapunov function, and obtaining a terminal voltage additional given value; and introducing the optimal PID controller parameter of the feedforward link and the additional given value of the terminal voltage to an original excitation system of the conventional phase modifier to obtain an additional excitation system of the phase modifier. The problems that in the prior art, the transient stability of the distributed phase modifier is weak, and the adjustment effect of a conventional control strategy of an excitation system of the phase modifier on the bus voltage is not obvious are effectively solved.

The invention discloses a networking type SVG transient synchronous stability control method based on AC / DC voltage hybrid control, and the method comprises the steps: calculating an internal potential phase angle of a networking type SVG system according to the operation parameter data of the networking type SVG system based on a DC voltage self-synchronization control module; judging whether the phase angle difference between the phase angle at the port of the networking type SVG system and the internal potential phase angle is smaller than 2 degrees or not, and judging that the networking type SVG system is stable when the phase angle difference is smaller than or equal to 2 degrees; when the phase angle difference exceeds 2 degrees, AC voltage stability enhancement control is carried out on the network construction type SVG system, and the output current of the network construction type SVG system is calculated; and judging whether the output current reaches a preset current amplitude limiting value or not, if the output current is greater than or equal to the current amplitude limiting value, judging that the current of the network construction type SVG system is saturated and has an instability risk, and implementing direct-current voltage stability enhancement control on the network construction type SVG system.

The invention discloses a control method and device for dynamic response optimization of a virtual synchronous machine and electronic equipment, and belongs to the technical field of new energy power generation. The method comprises the following steps: acquiring a grid-connected point voltage of an inverter; judging whether the voltage of the grid-connected point is less than M times of the rated voltage of the power grid, M belongs to (0, 1); responding to the condition that the grid-connected point voltage is less than M times of the rated voltage of the power grid, and accessing a feedforward link based on the angular frequency difference; and responding to the condition that the grid-connected point voltage is greater than or equal to M times of the rated voltage of the power grid, and cutting off a feedforward link based on the angular frequency difference. According to the method, overshoot can be suppressed, the active response speed can be improved, phase angle overshoot under the working condition of sudden drop of the power grid voltage can be reduced, and the requirement for the working condition of sudden drop of the power grid voltage during grid connection of the grid-forming inverter is met.

The invention provides a steam turbine optimal configuration system arranged at a high position and a low position, which at least comprises a high-position shaft system, a high-pressure cylinder, an intermediate-pressure cylinder, a low-pressure cylinder, a generator, a low-pressure cylinder, a generator, a first condenser and a second condenser, wherein the high-position shaft system is arranged close to the elevation position of an inlet header and an outlet header of a superheater and a reheater; the low-pressure cylinder and the generator are arranged on a low-position shaft system; the steam guide pipe is connected between a low-pressure cylinder on the high-position shaft system and the first condenser, the communicating pipe is connected with the steam exhaust end of a medium-pressure cylinder on the high-position shaft system, the steam inlet end of the low-pressure cylinder on the high-position shaft system and the steam inlet end of the low-pressure cylinder on the low-position shaft system, and the valve is arranged at the steam inlet end of the low-pressure cylinder on the low-position shaft system. And the steam in the communicating pipe in front of the steam inlet valve of the low-pressure cylinder on the low-position shaft system enters a heating heat exchange station through a heating valve and a pipeline. By means of the heating valve and a low-pressure cylinder steam inlet valve on the low-position shaft system, steam inlet of a low-pressure cylinder on the low-position shaft system can be adjusted according to specific seasons and loads, so that the commissioning and removing functions of the low-position shaft system are achieved, the steam inlet amount in the heating seasons is adjusted, and the heating steam pressure is maintained. Therefore, the optimal all-season and full-load operation condition is realized, and the purposes of saving energy and reducing consumption are achieved.

The invention discloses a power system transient stability control method and device based on active low voltage ride through of a wind turbine generator. According to the method, a near-end strategy optimization algorithm is taken as a core, and a reinforcement learning model is constructed: a fan grid-connected power system is taken as an environment, and multi-moment characteristic electrical quantities of a node model of the fan grid-connected power system are extracted to construct an observation state; and the end time of the active low-voltage ride-through is used as a control action. And through training and network learning of a near-end strategy optimization algorithm, the optimal low-voltage crossing end time is decided, and an optimal control strategy enabling the transient state of the system to be quickly recovered to be safe is generated. According to the method, transient stability control measures can be quickly and accurately given when the system is disturbed.

The present application relates to the technical field of converter transient stability evaluation, and provides a method and system for setting an angle frequency limiter to ensure global stability of a network device. The method includes extending the single-pendulum deceleration process of a virtual synchronous machine to a multi-pendulum deceleration process, and setting an upper limit of the angle frequency limiter based on a multi-pendulum stability condition. In the single-pendulum deceleration process of the virtual synchronous machine, the influence of potential energy and damping dissipation energy is considered simultaneously, and the damping dissipation energy is quantified approximately by using the concave-convex property of the angle frequency trajectory. Based on the potential energy and the approximately quantified damping dissipation energy, the maximum angle frequency limiter upper limit required for setting is solved by using the critical stability condition of the last pendulum in the multi-pendulum deceleration process, thereby completing the setting of the angle frequency limiter to ensure global stability of the network converter in the technical field of transient stability evaluation. The method can ensure that the virtual synchronous machine recovers to synchronous stable operation at least within the period of a single pendulum by using the angle frequency limiter control, and can obtain a larger upper limit of the angle frequency limiter setting by considering the damping effect.