452 results about "Reactive power control" patented technology

The invention relates to the technical field of power electronics, in particular to a photovoltaic off-grid inverter control method and system, and the method comprises the following steps: applying a test signal to identify an output interaction characteristic parameter, predicting the power generation power through combining with weather and attenuation, calculating the power fluctuation, and adjusting a current control parameter set. And calculating voltage and reactive power compensation parameters to generate an inverter control instruction, and combining a temperature load prediction trend to adjust a power allowable value to obtain a predictive power calibration coefficient. According to the invention, by analyzing the output interaction characteristics, enhancing the perception capability of the inverter to the actual operation environment, combining with the prediction of the photovoltaic power generation amount, realizing the prediction and influence evaluation of the power fluctuation, improving the adaptive adjustment capability of the current control parameters, improving the output voltage and reactive power control precision by utilizing the interaction characteristics, and optimizing the electric energy quality; and through thermal management of multi-point temperature and load prediction, the operation safety is improved, the service life of equipment is prolonged, and the operation performance of the photovoltaic off-grid system in a complex environment is improved.

The invention relates to an active and reactive collaborative optimization control method for a photovoltaic energy storage system based on a network-forming inverter, and the method achieves the effective control of active and reactive power through simulating the characteristics of a synchronous generator. And then collaborative optimization of active and reactive power control parameters is carried out. A system frequency response model is utilized to describe dynamic response of system frequency, and a dynamic equation of the system is converted into a discrete form in combination with the dynamic equation of the energy storage unit. Meanwhile, the optimization model is solved by considering system capacity limitation, so that transient frequency characteristics are improved, and frequency deviation after system disturbance is reduced. In addition, the minimum active power loss is taken as an optimization target, the voltage deviation is taken as a penalty term to be substituted into a target function, and a reactive power optimization target function is established. A PSO algorithm is adopted to solve a reactive power optimization function, and reactive power output of photovoltaic and energy storage is adjusted by adjusting VSG control parameters, so that the economical efficiency of a power grid is improved on the premise of ensuring qualified voltage.

The present application provides a reactive power feedback control-based control method for a commutation failure in a hybrid cascaded high-voltage direct-current power transmission system, a storage medium and an electronic apparatus, and particularly relates to a reactive power feedback control-based control method for a commutation failure in a hybrid cascade high-voltage direct-current power transmission system. The method mainly comprises the following steps: acquiring power data of a hybrid cascaded high-voltage direct-current power transmission system; calculating the reactive power supply of an inverter-side MMC-end alternating-current system, the reactive power supply of an inverter-side alternating-current filter, and the reactive power supply of an inverter-side LCC-end alternating-current system; solving a reactive power control instruction of an inverter-side MMC converter; and, on the basis of a critical voltage, determining whether to implement the reactive power feedback control-based control method for a commutation failure in the hybrid cascaded power transmission system. The method can effectively reduce the probability of commutation failures in hybrid cascaded power transmission systems, thus guaranteeing safe and stable operation of large-scale power grids.

The invention discloses a transformer area side energy storage type electric energy quality comprehensive treatment method, which comprises the steps of monitoring and data analysis, voltage out-of-limit control, power out-of-limit control, reverse transmission prevention control, voltage reactive power control, source network load storage coordinated optimization, distributed photovoltaic absorption, comprehensive line loss reduction and the like. The transformer area operation parameters are monitored in all directions, the big data analysis technology is used for analyzing and processing real-time detection data, the functions of transformer area side voltage out-of-limit control, power out-of-limit control, reverse transmission prevention and the like are achieved, and the transformer area side electric energy quality can be effectively improved; the distributed photovoltaic bearing capacity and the access capacity of the alternating current charging pile of the electric vehicle are improved, the comprehensive line loss rate is reduced, the comprehensive line loss can be reduced by 10%, the distributed photovoltaic bearing capacity can reach 150%, the access capacity of the alternating current charging pile of the electric vehicle can be improved by 200%, and 100% consumption of the distributed photovoltaic is achieved.

The invention discloses a system and a method for analyzing stability and oscillation transmission of a network-forming converter system, and belongs to the technical field of virtual synchronous generator control, and the system comprises an active power control loop which takes an active power deviation value as input, and outputs a power angle of a VSG system through an active integration part and a feedback part; the reactive power control loop takes the reactive power deviation ratio as input, and outputs the voltage amplitude of the VSG system through an active integration part and a feedback part; according to the analysis method, whether each state variable is stable or not is judged firstly, and then the intensity of oscillation transmission between the state variables is judged. According to the method, the stability of the system can be evaluated more accurately, and the accuracy of system stability analysis under dynamic disturbance is ensured; an oscillation transfer effect function is introduced, and the mutual influence between different state variables is quantitatively analyzed; and the dynamic fluctuation range of each state variable in the system can be accurately evaluated.

The invention discloses an optimized reactive power control and fault ride-through method and system for a hybrid commutation converter, and the method comprises the steps: introducing reactive power control and considering the constant voltage control of negative turn-off angle limitation, achieving the control of an extremely low turn-off angle through the active turn-off of a full-control device in the converter under a steady-state working condition, and further meeting the demands of a high power factor; the investment of passive filter equipment is reduced; under the alternating current fault working condition, forced commutation and negative turn-off angle operation are achieved through active turn-off of a full-control device, the receiving end power grid voltage is effectively supported while commutation failure of a half-control thyristor in the hybrid commutation converter is avoided, and the active power transmission level during the fault period is improved. The full-control characteristic of the reverse blocking type integrated gate commutation thyristor in the hybrid commutation converter is fully utilized, reactive power control under the steady-state working condition and stable power transmission under the alternating-current fault are achieved by optimizing active turn-off control, and the method has wide applicability and good application prospects.

The invention relates to the technical field of new energy power system control, and relates to a power decoupling method for cooperative control of voltage feed-forward compensation and adaptive virtual impedance. The method comprises the following steps: acquiring a power grid current and a power grid voltage, and calculating a reactive power measured value and an active power measured value of a power grid; virtual synchronous machine control is carried out, and a voltage feed-forward pre-compensation item is introduced into a reactive power control loop; calculating a reactive power control loop after VSG compensation, and obtaining VSG output side voltage and instantaneous angular frequency; self-adaptive virtual impedance control is adopted, a self-adaptive virtual impedance reference value is calculated, line impedance is dynamically adjusted, and a voltage loop input instruction voltage is calculated according to the line impedance; and adjusting the output performance of the inverter according to the instruction voltage. According to the invention, the problem of power fluctuation caused by VSG output voltage amplitude variation is effectively solved, and the dynamic influence of a power coupling item is weakened.

The invention discloses a virtual power plant voltage-reactive power coordination control method based on fusion of a graph neural network and deep reinforcement learning, and the method comprises the steps: explicitly introducing a topological structure of a power distribution network into the state representation of deep reinforcement learning in the form of graph data, and extracting and processing the graph structure data through the graph neural network; topological correlation and dynamic interaction among nodes in a power grid are accurately captured; and the extracted graph features and the traditional system state quantity are fused and input to the deep Q network for learning and decision making, so that the optimal coordination control of the distributed resources in the virtual power plant and the power distribution network equipment is output. The virtual power plant voltage-reactive power control method and device aim at solving the problem that in the prior art, perception on a power grid structure is insufficient, and the decision-making precision and robustness of virtual power plant voltage-reactive power control and the adaptability in a large-scale complex power distribution network are remarkably improved.

The static synchronous phase modifier comprises a DC / AC converter and a controller, the direct current side of the DC / AC converter is connected with an energy storage unit composed of the hybrid supercapacitor, and the alternating current side of the DC / AC converter is provided with an LC filter circuit; the controller adopts a virtual synchronous machine control technology to control the DC / AC converter, and comprises a power calculation part, an active power control part and a reactive power control part; the power calculation part is used for calculating actual active power and actual reactive power according to the current of the filter inductor, the voltage of the filter capacitor and the line current; the active power control part performs active power control according to the actual active power and the reference active power; the reactive power control part performs reactive power control according to the actual reactive power and the reference reactive power. According to the invention, frequency and voltage support can be provided when a short-circuit fault occurs in the line, frequency collapse is prevented, the low-voltage ride-through success rate of the wind turbine generator is improved, and the grid-connected strength is improved.

The invention relates to a fault current analysis method based on first-order Taylor expansion, and the method comprises the following steps: 1, determining a system control strategy which is a network construction type control strategy and comprises a power loop, a virtual impedance link and a voltage and current loop; the power loop comprises an active power control loop and a reactive power control loop; 2, constructing a differential algebraic equation set model capable of representing the dynamic state of the system; 3, according to the characteristic that the integral value does not suddenly change at the moment before and after the fault occurs, the steady state before the fault is utilized to solve and obtain an instant state variable value after the fault, and then an instant dq-axis current value after the fault and an instant current amplitude value after the fault are obtained; 4, performing first-order Taylor expansion on the constructed differential algebraic equation set at the solved post-fault instant state variable value and the dq-axis current value, and converting a nonlinear differential algebraic equation set model into a linear differential algebraic equation set; and 5, analyzing the fault current.

The invention provides a grid-connected power detection method and detection system for a three-phase four-wire photovoltaic grid-connected energy storage system. The method comprises the following steps: obtaining a total reactive power instruction according to a grid-connected total active power instruction and a reactive power control mode; calculating to obtain single-phase active power and single-phase reactive power of the power grid; performing closed-loop control according to the total reactive power instruction, the single-phase active power and the single-phase reactive power to obtain a control signal of closed-loop output; and performing grid-connected control on the inverter according to the control signal to obtain grid-connected active and reactive output. According to the method, starting from power definition, phase current is projected to a phase voltage direction and an orthogonal direction, deformation of product sum and difference is utilized, and active current and reactive current are averagely extracted through a periodic sliding window to obtain active power and reactive power, so that three-phase active and reactive independent decoupling control is realized; and the method can adapt to working conditions of unbalanced power grids and unbalanced power requirements.

The invention discloses a reactive power control method based on a photovoltaic grid-connected inverter, relates to the field of reactive power control methods, focuses on a new theory of reactive power control of the photovoltaic grid-connected inverter, and provides a reactive power control method based on the photovoltaic grid-connected inverter by deeply analyzing active and reactive power output characteristics of a grid-connected photovoltaic system and influences of the active and reactive power output characteristics on power grid voltage. A single-inverter control strategy based on a two-phase static coordinate system is provided, independent control of active power and reactive power is achieved, and constraint conditions about reactive power output such as inverter capacity, power transmission line limitation and direct current side voltage limitation are considered. The photovoltaic grid-connected inverter reactive power control method aims at improving the permeability of a power grid to photovoltaic energy grid connection by designing a new control method, meanwhile, voltage fluctuation of a point of common coupling (PCC) can be more efficiently restrained, and then the stability of the voltage of the power grid and the reliability of a power system are improved.

Provided in the present disclosure are a converter system of a wind turbine generator system, and a wind turbine generator system and an offshore wind farm. The converter system comprises: a voltage source converter and a current source converter; and a converter control apparatus, which is configured to control the operation of the voltage source converter and the current source converter by means of taking into account an internal circulating current of a wind turbine generator system in voltage outer-loop control of the voltage source converter and by means of taking into account the internal circulating current in active and reactive power control stages of the current source converter.

The invention discloses an SLCC dynamic self-adaptive harmonic compensation control method, system and equipment and a medium. The method comprises the following steps: acquiring a three-phase alternating current on a common coupling point of a commutation converter and a static var filter device, a three-phase alternating current on a bridge arm branch of the static var filter device and a fundamental frequency control voltage of a fundamental frequency reactive power control loop; based on the number of converter valve pulses, extracting the three-phase alternating current on the common coupling point and the three-phase alternating current on the bridge arm branch to obtain a specified subharmonic suppression current instruction and a specified subharmonic suppression voltage; calculating based on the specified subharmonic suppression voltage and the fundamental frequency control voltage to obtain a bridge arm modulation voltage of the static var filter device; harmonic compensation is carried out on the multi-source self-adaptive commutation direct current sending-out system based on the bridge arm modulation voltage; the harmonic current generated by the common point can be eliminated through extraction and suppression of the harmonic current of the common point, the power quality of grid connection of the direct-current converter valve is remarkably improved, and the precision and stability of harmonic compensation are improved.

The invention discloses a wind turbine generator low-voltage ride-through dominant parameter analysis method based on trajectory sensitivity, and relates to the technical field of low-voltage ride-through, and the method comprises the steps: screening parameters related in a reactive power control process according to voltage sensitivity characteristics; calculating the trajectory sensitivity of the parameters, and extracting the frequency characteristic of the trajectory sensitivity based on a discrete Fourier transform method, namely the error characteristic caused by the difference between the model parameters and the actual parameters; the method comprises the following steps: setting an average amplitude index and an amplitude ratio index of parameters, evaluating the influence capability of the parameters, screening the parameters based on the average amplitude index to obtain a candidate parameter set, setting the number of dominant parameters, sorting the candidate parameters from small to large according to the difference between the trajectory sensitivity amplitude ratio index and the error amplitude ratio index of the parameters, and parameters with serial numbers smaller than the number of the dominant parameters are selected as dominant control parameters, so that the influence of each parameter on the bus voltage can be quantitatively evaluated, and the dominant control parameters of the wind turbine generator in the low voltage ride-through period are accurately identified.

The embodiment of the invention relates to a dynamic reactive power control method and device for a new energy plant station, and the method comprises the steps: calculating a dynamic safety domain of virtual impedance based on a real-time estimation value of power grid impedance; based on a multi-time scale reinforcement learning algorithm, generating a virtual impedance control quantity under the constraint of the dynamic security domain; obtaining a reactive power output error value, and correcting the virtual impedance control quantity by using the reactive power output error value; and performing reactive power output control on the inverter of the plant station based on the corrected virtual impedance control quantity. According to the technical scheme provided by the embodiment of the invention, the power grid impedance is predicted through the multi-time scale reinforcement learning algorithm, the virtual impedance control quantity is generated accordingly, the upper layer prediction model can predict the impedance change trend in advance and provide a prospective reference for lower layer dynamic correction, and the lower layer dynamic correction model can realize instantaneous disturbance suppression. And rapid fine tuning of the virtual impedance is realized, so that more accurate virtual impedance control quantity can be obtained.

The invention relates to the technical field of power grid energy storage control, and particularly discloses a network construction type energy storage system and a control method thereof, and the system comprises a parameter collection module which obtains the voltage, frequency, short-circuit capacity ratio, phase angle and other power grid operation parameters of a grid-connected point in real time; the scene recognition module judges the power grid scene of the energy storage system according to the acquired parameters, wherein the power grid scene comprises a weak power grid scene, a fault scene, an oscillation scene, a phase angle jump scene and a power loss scene; the strategy library module stores control strategies for each scene, including active / reactive control, active / reactive decoupling, overload support, low-frequency oscillation suppression, phase angle stabilization and black start strategies; and the adaptive control module retrieves and calls a corresponding strategy from a strategy library according to an identification result, performs adaptive control on the energy storage system, and realizes intelligent response and stable support for a complex power grid environment. According to the invention, intelligent response and stable support of the energy storage system to a complex power grid environment are effectively realized.

Systems and methods for supplying power (both active and reactive) at a medium voltage from a DCSTATCOM to an IT load without using a transformer are disclosed. The DCSTATCOM includes an energy storage device, a two-stage DC-DC converter, and a multi-level inverter, each of which are electrically coupled to a common negative bus. The DC-DC converter may include two stages in a bidirectional configuration. One stage of the DC-DC converter uses a flying capacitor topology. The voltages across the capacitors of the flying capacitor topology are balanced and switching losses are minimized by fixed duty cycle operation. The DC-DC converter generates a high DC voltage from a low or high voltage energy storage device such as batteries and / or ultra-capacitors. The multi-level, neutral point, diode-clamped inverter converts the high DC voltage into a medium AC voltage using a space vector pulse width modulation (SVPWM) technique.

The invention discloses a power oscillation suppression method and a power oscillation suppression system for a multi-construction-network type converter parallel system, which relate to the technical field of converter control and comprise the following steps of: acquiring voltage, current and voltage frequency output by a three-phase converter at a grid-connected point in the multi-construction-network type converter parallel system; calculating active power and reactive power and inputting the active power and the reactive power into the virtual oscillator; according to the voltage frequency and the rated frequency, system power reference compensation is obtained through an introduced proportional differential controller, then the active power and an active power reference value are combined, frequency deviation is obtained through an active droop link of a virtual oscillator, and then a voltage phase angle is obtained through calculation; meanwhile, the reactive power is subjected to a reactive power control link of the virtual oscillator to obtain a voltage amplitude; and calculating a system reference voltage according to the voltage amplitude and the voltage phase angle, and performing real-time adjustment on the output of the three-phase converter through voltage and current double-closed-loop adjustment and PWM (Pulse Width Modulation) control so as to suppress the frequency oscillation of the system.

The invention discloses an energy storage type SOP black-start method, system and device based on improved VSG network construction control and a medium, and relates to the field of power grid black-start, and the method comprises the steps: an energy storage type converter MMC carries out the active and reactive control based on an improved VSG network construction control strategy; a non-fault side MMC is controlled to firstly close an isolation circuit breaker and slowly charge a direct-current capacitor, and when the voltage reaches a set threshold value, a current-limiting resistor is quitted; the fault side MMC is started by the same step as the non-fault side MMC; after synchronization is completed, AC circuit breakers between the non-fault side MMC and the feeder load and between the fault side MMC and the feeder load are closed respectively; based on the collected power grid power data, MMC output parameters are adjusted to meet the power grid connection condition, the control mode is switched according to the grid connection state, and the black start process is ended. And by arranging the black start resistor for current-limiting charging and sub-module voltage balance control, the phenomena of overcurrent and voltage unbalance in the black start process are avoided.

The invention discloses a variable frequency phase shift control DAB type single-stage inverter reactive power control method, system and device and a medium, and belongs to the technical field of power electronic converter control, and the method comprises the steps: setting a reactive power instruction as zero; when the reactive power instruction changes, the active power instruction and the reactive power instruction at the current moment are decomposed into a direct-axis current reference value and a quadrature-axis current reference value respectively; comparing the reference value with an actual sampling value, calculating an error compensation amount by using a PI controller, and determining the amplitude and phase of the AC side current according to the compensation amount; according to the amplitude and the phase of the voltage and the current, a DAB frequency conversion phase shift control curve is calculated; and generating a PWM (Pulse Width Modulation) signal according to the frequency conversion phase shift control curve obtained by calculation, wherein the PWM signal is used for driving a DAB inverter to carry out power transmission. According to the invention, on the premise that no extra hardware circuit is introduced, dynamic adjustment and accurate control of the instantaneous reactive power of the AC output side can be realized.

The invention discloses a time sequence fault current-limiting control method and system compatible with a grid-connected guide rule for a network construction type doubly-fed wind turbine generator, and the method comprises the following steps: freezing external power control when a low-voltage ride-through event of a power grid is detected at the initial stage of a fault, and suppressing transient overcurrent through dynamically adjusting the resistance component of virtual impedance; in the fault stable stage, an electromotive force compensation increment is calculated on the basis of grid-connected guide rule requirements at the moment 4 tau after the fault occurs; in the fault clearing stage, after it is detected that the fault is cleared, electromotive force compensation is stopped; gradually recovering the virtual impedance to a rated value through the dynamic coefficient A; in the fault recovery stage, active control and reactive control are recovered in sequence, power output is recovered to the level before the fault within one second, and meanwhile the virtual impedance amplitude is gradually recovered to the rated value along with the voltage phase difference; the voltage phase jump amplitude and the voltage drop amplitude determined by the method have high robustness.

The invention belongs to the technical field of power electronic converter control, and discloses a control method of a grid-forming type doubly-fed asynchronous wind power generation system with power control capability, which comprises a control process of a rotor-side converter and a control process of a grid-side converter, and is characterized in that the rotor-side converter forms a grid-forming type characteristic at a motor stator winding port, and the grid-side converter forms a grid-forming type characteristic at a motor stator winding port; the energy injected into the direct current bus capacitor is controlled; the grid-side converter maintains the input and output energy balance of the DC bus capacitor so as to control the voltage of the DC bus capacitor to be constant; the control process of the rotor side converter comprises a frequency support control loop, a power control loop, a voltage and current inner loop and pulse width modulation control, and the control process of the grid side converter comprises a direct current voltage control loop, a reactive power control loop, an alternating current control loop and pulse width modulation control. According to the invention, the capability of controlling the output power can be provided while the network construction type power dynamic index is realized.

The invention discloses a voltage dynamic support capability evaluation method suitable for grid-connected equipment of a network construction converter. The method comprises the following steps: firstly, acquiring a port voltage amplitude and a phase angle of the grid-connected equipment of the network construction converter, a voltage amplitude and a phase angle of a grid-connected point and grid-connected impedance of the grid-connected equipment of the network construction converter; and then, according to a reactive outer ring control strategy of the grid-connected equipment of the network construction converter, selecting a corresponding calculation formula for the evaluation index of the dynamic voltage supporting capability of the grid-connected equipment of the network construction converter, and according to the obtained data, calculating the evaluation index of the dynamic voltage supporting capability of the grid-connected equipment of the network construction converter in real time. Compared with the short-circuit ratio index of the traditional evaluation system strength, the voltage dynamic support capability evaluation index can accurately evaluate the voltage support capability of the grid-connected equipment of the network construction converter, and can quantitatively analyze the influence of the reactive power control parameters of the grid-connected equipment of the network construction converter on the voltage support capability; the method is of great significance in improving the voltage supporting capacity of the grid-connected equipment of the grid-forming converter and guaranteeing safe and stable operation of a power system.

The invention discloses a new energy reactive power control method for transient overvoltage suppression of a direct-current sending-end power grid, and the method comprises the steps: estimating the change trend of the voltage of a power grid through the current and historical signals of the voltage of the power grid, calculating the additional value of a reactive power instruction to generate a reactive power advanced control effect, and combining a reactive power optimization value subjected to delay compensation. And the instruction value can ensure that the new energy effectively outputs reactive power to participate in transient overvoltage suppression of the direct current converter station. According to the method, the new energy reactive power instruction value can be improved and optimized only on the basis of the existing electrical quantity observation signal without modifying the topological structure of a direct current converter station and a new energy power generation system and without additionally arranging various reactive compensation devices or various voltages or voltage sensors; no additional influence is generated on links such as new energy power instruction tracking control and direct current converter station power control, and the method has good engineering practicability and scene adaptability.

The invention discloses a real-time voltage-reactive power control method for a high-permeability photovoltaic flexible power distribution system, and the method comprises the steps: 1, considering the real-time response function of an inverter, and building a droop control model of the inverter; 2, flexible power distribution system regulation and control equipment is arranged, the flexible power distribution system regulation and control equipment comprises a topology variable intelligent soft switch and a photovoltaic device, and models of all kinds of equipment are established according to the flexible power distribution system regulation and control equipment; and 3, based on the models in the step 1 and the step 2, establishing a real-time voltage-reactive power control model containing the high-permeability photovoltaic flexible power distribution system, and by solving the model, outputting a real-time optimization control scheme of the flexible power distribution system. According to the method, the transmission capacity of the flexible power distribution system and the photovoltaic strong randomness are comprehensively considered, and a certain reactive power and a droop control function of the inverter are reserved through the topology variable intelligent soft switch, so that the real-time voltage safety and stability of the system are guaranteed.

The invention relates to an AC transient voltage regulation control method and system for a flexible DC system, and belongs to the field of flexible DC power transmission. When the AC voltage exceeds a normal operation range but does not enter an AC high-low voltage ride-through range, the system enters AC transient voltage regulation control, and upper and lower limit values of transient voltage regulation are used as voltage reference values of transient voltage regulation to obtain a reactive power reference value under the transient voltage regulation; adding the reactive power reference value in the alternating-current voltage mode and the reactive power reference value in the alternating-current voltage control mode to obtain a final reactive power reference value, and subtracting the reactive power reference value under transient voltage regulation from a set reactive power reference value in the reactive power control mode to obtain the final reactive power reference value. And finally, controlling the bridge arm voltage by using the final reactive power reference value. The reactive power can be dynamically adjusted in real time according to the upper and lower limit values of AC transient voltage regulation to suppress further deterioration of the AC voltage, and the stability of the system is improved.

The invention discloses a VSG negative sequence harmonic current control method under an asymmetric fault of a power grid, and the method comprises the steps: analyzing an instantaneous expression of VSG output power under an asymmetric working condition, and obtaining a quantitative relation between power frequency doubling fluctuation and positive and negative sequence voltage and current; introducing a direct current part of VSG reactive power output into a reactive power control ring, and constructing reactive power control ring control; positive sequence voltage current and negative sequence current are independently controlled in a positive and negative sequence separation mode; and unifying the positive sequence modulation signal and the negative sequence modulation signal to obtain a total PWM modulation wave signal, and setting a reference value for a negative sequence current loop, so that the VSG output current is balanced. According to the invention, the influence of power oscillation on the control effect of the VSG can be improved, the negative-sequence current harmonic waves can be suppressed, and the electric energy quality of the VSG is greatly improved.

A method for regulating voltage of electric power provided by an energy plant coupled to an electric power grid, the energy plant having at least one inverter-based resource ("IBR") coupled to the electric power grid via at least one inverter, the method comprising: using a control system communicatively coupled to an inverter of an IBR, implementing an automatic voltage regulator ("AVR") in the control system, the AVR having selectable control modes including a voltage control mode, a reactive power control mode, and a power factor control mode; receiving one or more command messages at the AVR for selecting a control mode; generating one or more command messages for controlling operations of the inverter; and, transmitting the one or more command messages for controlling operations of the inverter from the AVR to the inverter of the IBR for controlling operations of the inverter in accordance with the control mode selected.

The invention discloses a network construction type energy storage transient stability optimization control method and system considering reactive power degradation, and belongs to the field of power system transient stability control. According to the method, a network construction type energy storage grid-connected system model is constructed, a reactive power degradation effect dynamically triggered by a reactive power control loop is analyzed, and an active power loop optimization control equation is established according to the reactive power degradation effect. On the basis, a self-adaptive torque adjusting module is embedded in an active control module, and when it is monitored that the internal voltage of the inverter is reduced to 50% of a rated value, the reference torque is automatically and dynamically corrected so as to improve the power angle transient stability margin of the system. Simulation results show that the method can effectively restrain the instability of the network construction type energy storage power angle, obviously enhance the transient stability of the system, and guarantee the safe and reliable operation of the power grid.