533results about "Flexible AC transmission" patented technology

The invention discloses an intelligent self-adaptive suppression method for oscillation of a data-driven SVG (static var generator) grid-connected system. Obtaining the capacitor voltage of the direct current side of the SVG and the actual voltage and the actual current of the grid connection point of the SVG, and respectively calculating the active power output by the SVG and the voltage amplitude output by the SVG according to the actual voltage and the actual current; a current reference value is generated through a voltage outer loop; the active power output by the SVG, the voltage amplitude output by the SVG and the voltage of the direct current side of the SVG are input into a DeePC controller to be processed, and an additional current reference value is obtained; and then the current error is obtained by adding the current reference value output by the voltage outer loop and subtracting the actual current, and then the current error is input to the voltage inner loop for processing to obtain a modulation wave voltage amplitude signal. According to the method, the oscillation of the converter grid-connected system can be suppressed under the condition that the dynamic characteristics of the converter and the conditions of the power grid are changed, and the problems of insufficient fixed structure and parameter sensitivity of the traditional SVG are solved.

The invention discloses a reactive voltage bimodal control method and system suitable for a new energy power station, and belongs to the technical field of power system voltage control. The invention provides a dual-stage control optimization mechanism based on cooperation of a distributed phase modifier and a static var compensator in order to solve the problems of difficult steady-state voltage regulation and transient voltage instability of a new energy power station caused by wind-light output fluctuation and system short-circuit capacity reduction. According to the method, in steady-state operation, minimization of grid-connected point voltage deviation and maximization of dynamic reserve capacity of a phase modifier are taken as targets, reactive power output of two types of equipment is optimally distributed, and a proper amount of dynamic margin is reserved to support transient requirements; when it is detected that the voltage sag exceeds a safety threshold value, a transient response mode is immediately switched to, that is, phase modifier strong excitation control is activated, and reactive power output, reduced due to low-voltage limitation, of the static reactive power compensator is compensated; and when the voltage enters a recovery stage, triggering the phase modifier to reduce the output in advance through a pre-action instruction, and delaying to recover the steady state mode after the switching of the static var compensator is completed. A double safety protection mechanism is embedded in the whole control process, whether the grid-connected point voltage is in a safety interval or not is verified in real time, and the minimum operation interval of the switching equipment is forced to be executed. Simulation results show that the method can remarkably improve the voltage operation index of the new energy power station, the steady-state voltage fluctuation amplitude is greatly reduced, the transient fault recovery time is obviously shortened, the overvoltage peak value is effectively restrained to be within a safe range, and the industrial problem that the steady-state adjustment precision and the transient supporting capacity cannot be both considered by single reactive power equipment is solved.

The invention provides an APF and SVG cooperative control-based electric energy quality comprehensive treatment system, and belongs to the technical field of intelligent power grid industry and electric energy quality comprehensive treatment, and the system comprises the steps of obtaining a power grid current signal and a voltage signal, and detecting a harmonic component and a voltage deviation through a harmonic detection module; a collaborative decision controller is adopted to determine a compensation strategy according to the harmonic component and the voltage deviation, and compensation tasks of an active power filter channel and a static var generator channel are distributed; harmonic compensation current is generated through an active power filter channel, and high-frequency harmonics are suppressed; reactive compensation current is generated through a static var generator channel, and voltage fluctuation is stabilized; and the compensation current is filtered through the filtering module and is output to a power grid. The electric energy quality comprehensive treatment system can effectively inhibit power grid harmonic waves, stabilize voltage fluctuation and improve electric energy quality, and is suitable for a complex power grid environment.

The invention, which relates to the technical field of the electrical automation equipment, provides a network construction type high-voltage direct-hanging battery energy storage system and method, comprising a high-voltage direct-hanging battery energy storage system, a network construction control module, an internal potential power angle limiting module and an internal potential amplitude limiting module. The high-voltage direct-hanging battery energy storage system is used for connecting battery modules in the system to direct-current buses of H-bridge circuits in a scattered mode, and the H-bridge circuits are cascaded on the alternating-current side and then connected to a middle-high-voltage power grid through a filter inductor. The networking control module generates an internal potential power angle and internal potential amplitude information by simulating the characteristics of a synchronous machine; the internal potential power angle limiting module and the internal potential amplitude limiting module are respectively used for calculating amplitude limiting values of an internal potential power angle and an internal potential amplitude in real time; and the amplitude-limited internal potential power angle and the amplitude-limited internal potential amplitude generate a modulation signal of the high-voltage direct-hanging battery energy storage system. According to the invention, current limitation and transient stability improvement in the transient fault period of the high-voltage direct-hanging battery energy storage system can be realized.

The invention discloses an SVG-based photovoltaic grid-connected reactive power compensation method and system, and relates to the technical field of photovoltaic grid-connected compensation, and the method comprises the steps: monitoring the output power fluctuation of a photovoltaic array, and building a first electrical parameter feature vector; photovoltaic grid-connected impedance fluctuation characteristics are monitored, and a second electrical parameter feature vector is established; extracting a dynamic harmonic component and a reactive demand spectrum; generating a dynamic adjustment instruction set of SVG trigger pulse phase-amplitude according to the dynamic harmonic component and the reactive demand spectrum; and issuing the dynamic adjustment instruction set to a carrier phase shift controller of the SVG power unit for grid-connected interleaving compensation modulation. The technical problems that in the prior art, due to output power fluctuation and impedance change, harmonic waves of a photovoltaic grid-connected system are difficult to restrain, and then the electric energy quality is poor, and the system operation stability is insufficient are solved, and the technical effects that optimal modulation of SVG trigger pulses is achieved, and the electric energy quality and the operation stability of the photovoltaic grid-connected system are improved are achieved.

The invention discloses a modular high-voltage SVG circulating current suppression method. The method comprises the steps of obtaining and preprocessing module circulating current, voltage and state data; constructing an enhanced phase space fused with multiple physical quantities, extracting circulating current phase features and generating dynamic trend prediction data; calculating optimal feed-forward and feedback virtual impedance parameters based on phase characteristics and trend prediction; and generating a module control voltage correction value and a PWM control signal by applying a multi-time scale hybrid control strategy. Through hybrid control of phase space reconstruction of topology perception, multi-dimensional entropy analysis and stability guarantee, efficient suppression of the circulating current is realized, and the stability and robustness of the SVG system are improved.

The invention discloses a voltage regulation and control method and system suitable for a distributed energy storage photovoltaic transformer area of a power distribution network. The method comprises the following steps: establishing a transformer area active power distribution network model for carrying out voltage regulation and control by considering distributed photovoltaic, wind power, an energy storage system, a static var compensator and a load node; a voltage regulation problem is modeled as a Markov decision process, a state space comprises multi-source power information and energy storage state information, and an action space is controlled quantities of a static var compensator and an energy storage system; a Markov decision is solved by adopting a depth deterministic strategy gradient algorithm based on Actor-Critic dual networks, a control action is generated through a strategy network Actor, and a current strategy is evaluated through a value network Critic for training; and inputting the trained strategy network based on the current observation state, outputting an optimal energy storage active / reactive power output and SVC reactive power compensation control instruction, realizing online adjustment of node voltage, and realizing stable control of transformer area voltage.

The invention relates to the technical field of power electronics, in particular to a network construction type STATCOM topological structure with a super-capacitor and a control method thereof, the topological structure is a star-shaped chain network construction type STATCOM system with a super-capacitor module power unit, the power unit comprises a super-capacitor module and an H-bridge module, and the super-capacitor module is connected with the H-bridge module in parallel; the super-capacitance module is formed by cascading three sub-modules, and each sub-module comprises a super-capacitor, a filter inductor and a DCDC circuit; the control method comprises the steps of voltage feed-forward unit phasor calculation, reactive voltage control and virtual internal potential angle calculation, virtual impedance amplitude limiting logic, bridge arm current reference instruction calculation and modulation wave instruction calculation. According to the invention, the applicability of the super capacitor module is enhanced, the design cost is saved, mutual interference between the frequency modulation characteristic and the inertia damping characteristic is avoided, the active power steady state control precision is improved, and the product safety is improved.

The invention provides an artificial intelligence driving cascade direct-hanging SVG carrier phase shift optimization method and system, and the method comprises the steps: constructing a sensor input layer, a slow decision layer and a fast execution layer; multidimensional power grid state information collected by the sensor input layer is transmitted to the slow decision-making layer and the fast execution layer; the slow decision-making layer outputs modulation control parameters based on the reinforcement learning neural network; and the fast execution layer outputs a modulation signal based on the modulation control parameter and the multi-dimensional power grid state information, and is used for driving the cascaded H-bridge module. The system is simple in structure and low in control and construction cost, a fast and slow double-layer coordination framework is constructed, and a reinforcement learning neural network is combined in a method level, so that the nonlinear fitting capability is realized, dynamic parameter adjustment and collaborative optimization can be carried out for multiple dimensions and multiple targets, the stability of a cascade structure is enhanced, and the stability of the cascade structure is improved. And the comprehensive performance of the SVG is improved.

The invention discloses a high-voltage SVG adaptive voltage control method based on deep learning, and belongs to the technical field of power equipment, and the method comprises the following steps: S1, multi-source data collection and preprocessing: the S1, multi-source data collection and preprocessing comprises a data collection module and a data preprocessing module, the data acquisition module comprises a high-precision sensor network and acquires various data in real time; the data preprocessing module comprises missing value filling through a sliding window method, wavelet transform denoising, multi-dimensional feature proof construction and normalization processing; s2, constructing a deep learning model, wherein the construction of the deep learning model in S2 comprises a model framework module, a network parameter module and a training strategy module. According to the method, the nonlinear characteristics of the power grid are captured through the deep learning model, the method can adapt to dynamic scenes such as power grid topological structure sudden change and new energy output intermittence in real time, and in the power grid with the new energy permeability exceeding 30%, the voltage regulation error can be reduced to + / -0.5% and is remarkably superior to + / -2% of a traditional method.

The invention discloses a VSG transient stability control method based on PSS power angle compensation and integral reactive loop cooperation, and the method comprises the steps: constructing an improved rotor motion equation compensation mechanism based on a power system stabilizer, and based on the dynamic parameters of the voltages vabc and pcc at a PCC point and the currents iabc and pcc flowing into the PCC point which are collected in real time, carrying out the compensation of the current iabc and pcc at the PCC point under the condition that the working condition is that the voltage of a power grid drops greatly. The dynamic characteristic of active power is ensured; constructing a PSS parameter optimization method based on zero point position constraint; an integral link is embedded in the traditional voltage-reactive droop characteristic, integral reactive loop control is constructed, and steady-state voltage deviation is eliminated; the output compensation power angle delta and the output voltage amplitude E are cooperatively applied and converted into dq-axis voltage components Ed and Eq, the dq-axis voltage components Ed and Eq are sent to a voltage and current double closed loop, a driving signal is generated through SVPWM, and the stability of the system is enhanced.

The invention discloses a closed-loop transformer based on a single-core symmetric phase-shifting transformer and a control method thereof. The control method comprises the following steps: establishing a target closed-loop transformer, and establishing a first connection strategy and a first access strategy based on the target closed-loop transformer; acquiring a first control target of the target loop closing transformer; and based on the first control target, the target loop closing transformer is controlled in combination with the first connection strategy and the first access strategy. By adopting the structure that the single-core symmetrical phase-shifting transformer bank and the voltage-regulating transformer bank are connected in series, the amplitude-phase decoupling regulation of the voltage phasor difference on the two sides of a loop closing point is realized, the control rule and mode are simpler, the wiring is simple and convenient, the regulation is flexible, and the regulation range is wider and the regulation precision is higher.

The invention discloses an SVG-containing power grid stability adaptive control method and system under a complex working condition, and relates to the technical field of power system stability control, and the method comprises the steps: analyzing a key operation working condition with the worst system stability; on the basis of the change condition of the operation condition, simplifying the worst key operation condition small interference robust stability problem, and obtaining an SVG control parameter set; based on the SVG reactive current collected in real time, the system adaptively selects SVG control parameters to control the stability of the power grid. According to the method, by adaptively adjusting the control parameters of the SVG, it can be ensured that the CSCR of the system is always reduced under the key operation condition of the SVG, and therefore the stability of the system is improved; the offline calculation of the control parameter set and the online adjustment of the control parameters are combined, so that the reasonability of the control parameters is ensured, and the response speed of the system is improved.

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 reactive compensation optimal configuration method and system of a new energy base, equipment and a medium, the method performs steady-state configuration of initial reactive capacity based on load flow calculation, can obtain effective steady-state reactive compensation configuration in a full output range, improves the robustness of steady-state reactive compensation, and improves the optimal configuration of the reactive compensation of the new energy base. A global coupling optimization architecture crossing steady state and transient state is constructed for the first time, closed-loop convergence of three optimization configuration stages is realized, so that global optimal configuration of reactive compensation is realized, and meanwhile, reasonable division and matching between two types of dynamic reactive compensation equipment, namely a phase modifier and an SVG / STATCOM, are realized; therefore, the new energy base not only can solve the transient voltage problem, but also has high power grid support strength, and the total configuration cost is greatly reduced while the requirements of standards, short-circuit ratio and transient voltage stability are met.

The invention relates to a network construction type STATCOM (static synchronous compensator) analysis model based on DC capacitance dynamics, and belongs to the technical field of power distribution networks. The invention aims to realize the simulation of the synchronization characteristic of a synchronous machine by utilizing the similarity between the dynamic state of the direct current capacitor and the dynamic state of a generator rotor, namely a grid-building STATCOM analysis model based on the dynamic state of the direct current capacitor for the self-synchronous control of the direct current capacitor. The control structure of the internal frequency of the STATCOM on the direct current voltage is adjusted, a voltage equation under a synchronous coordinate system is deduced according to the superposition theorem and a topological graph, and the equivalent synchronous machine is obtained according to the equivalent principle, so that an equivalent rotor motion equation of the equivalent synchronous machine is obtained. According to the control mode, the internal frequency of the equipment can be adjusted to realize synchronization with the power grid, and stable operation of the direct-current side is ensured by controlling the direct-current voltage.

The invention belongs to the technical field of power electronic conversion, and particularly discloses an MMC-STATCOM system direct optimization model prediction control method and system, and the method comprises the steps: respectively calculating a differential mode voltage and a common mode voltage between an upper bridge arm and a lower bridge arm of each phase; third harmonic voltage is injected into the upper bridge arm and the lower bridge arm of each phase to obtain upper bridge arm voltage and lower bridge arm voltage of a newly-added third voltage component of each phase; and based on the obtained voltage of the upper and lower bridge arms of the newly added three-time voltage component, determining the input number of the sub-modules of the upper and lower bridge arms of each phase by adopting a nearest level approximation modulation strategy, and determining the input sub-module of each bridge arm according to the capacitor voltage sequence of each sub-module of the bridge arms and the current direction. According to the method, on the basis of keeping a discrete control structure, direct injection of third harmonic voltage under an MPC framework is achieved, and higher real-time performance and expandability are achieved.

The invention discloses an SVC (static var compensator) control method of a high-power power supply system based on a predictive active disturbance rejection mechanism, which comprises the following steps of: establishing a combined operation time domain model of the high-power power supply system and a static var compensator, and acquiring delay parameters in advance by utilizing a system identification method; predicting and calculating a reactive instruction signal of the static var compensator based on the voltage reference signal of the load side of the power supply system and the direct current side current; inputting the predicted reactive instruction into a linear active disturbance rejection controller, estimating the total disturbance of the system in real time through an extended state observer, generating a compensated control signal in combination with a proportional differential combination control law, and driving the system to output a tracking and predicting reactive instruction; and the tracking prediction reactive instruction acts on the static var compensator to form closed-loop anti-interference control. Through cooperation of prospective reactive power instruction generation based on a load side voltage reference signal and disturbance real-time compensation of a linear active disturbance rejection control framework, a grid side reactive power impact value is reduced, and bus voltage stability is enhanced.

The invention discloses an SVG fault ride-through capability evaluation method and system based on HIL simulation, a medium and equipment. The SVG fault ride-through capability evaluation method comprises the steps that photovoltaic power station operation parameters, power grid operation parameters and SVG dynamic reactive power compensation device parameters are acquired; constructing a simulation model according to the operation parameters of the photovoltaic power station, the operation parameters of the power grid and the parameters of the SVG dynamic reactive power compensation device, and connecting the simulation model and SVG controller hardware; according to a preset fault ride-through test method, setting a corresponding test parameter combination for each test condition; according to a preset simulation algorithm and each test parameter combination, controlling the simulation model and SVG controller hardware to perform simulation to obtain a simulation test result; and evaluating the simulation test result to obtain an SVG fault ride-through capability index. Through the method based on controller hardware-in-the-loop simulation test, the reliability and the accuracy of evaluating the fault voltage ride-through capability of the dynamic reactive power compensation device of the photovoltaic power station are improved.

The invention discloses a precise temperature control water cooling system based on an SVG technology, and relates to the technical field of water cooling systems, and the system comprises an SVG control core module which is used for generating and dynamically adjusting a water cooling system control instruction according to the operation state and heat dissipation demands of an SVG reactive power compensation device; and the multi-dimensional temperature monitoring network is composed of various temperature sensors distributed in the water cooling pipeline, the SVG device heat dissipation terminal and the cooling liquid storage cavity, and is used for collecting temperature data and generating temperature field information. A heat dissipation control logic of an SVG reactive power compensation device is converted into a control instruction, a temperature control target is converted into a control instruction parameter, a corresponding relation between the parameter and a temperature adjustment amplitude is established, and the control instruction parameter is adjusted by using a particle swarm optimization algorithm, so that the control instruction can be dynamically optimized according to an actual operation state of the SVG device; compared with a traditional fixed parameter control mode, the response speed and accuracy of temperature control are remarkably improved.

The invention discloses an anti-saturation equivalent virtual impedance grid-forming type SVG fault current-limiting control method, which comprises the following steps of: inverting a direct current into an alternating current through an inverter, and filtering high-frequency harmonics through a filter to obtain a sine wave alternating current meeting a grid-connected requirement. A three-phase alternating current signal is collected in real time, coordinate transformation is carried out through a Park transformation module, and a modulation signal is obtained. The modulation signal is compared with a triangular carrier signal, a driving signal is generated, the on-off time of a power switching device of the inverter is controlled, the amplitude and phase of output voltage and current are adjusted, accurate control over the output power of the grid-connected inverter is achieved, and the power grid access requirement is met. According to the method, the limitation of traditional fixed parameters is broken through, and the robustness of the system to a complex fault scene is improved. In addition, manual intervention or a complex mode switching program is not needed, automatic smooth transition between different working conditions can be achieved, and powerful technical guarantee is provided for stable operation of a power grid.

The embodiment of the invention discloses a negative damping elimination method, device and equipment based on SVG and a storage medium, and the method comprises the steps: carrying out the impedance scanning of the SVG in a range of 1-3000Hz, obtaining the positive-sequence impedance and negative-sequence impedance of the SVG under different operation conditions, and determining the leading operation condition of the SVG impedance; determining the positive sequence equivalent impedance and the negative sequence equivalent impedance of the SVG grid-connected point according to the positive sequence dominant impedance and the negative sequence dominant impedance of the SVG under the dominant operation condition; determining the value ranges of the positive sequence damping correction value and the negative sequence damping correction value of the SVG; the maximum value of the intersection of the two value ranges is determined as SVG compensation damping, and the SVG compensation damping is merged into an SVG grid-connected point port; according to the scheme, only two unknown parameters including the positive sequence damping correction value and the negative sequence damping correction value are involved, the parameters can be calculated based on an analytic formula pure algebraic equation, the calculation mode is simple, the port impedance characteristic negative damping of the SVG in the full frequency band within the range of 1-3000 Hz can be eliminated, and the problem of high-frequency oscillation is thoroughly solved.

The invention discloses a distance adaptive protection method and system for a phase-shifting transformer in an active power distribution network, and the method comprises the steps: determining an input and output voltage relation based on an equivalent impedance model of the phase-shifting transformer, and analyzing the network operation mode change caused by the access to the power distribution network, and calculating positive sequence, negative sequence and zero sequence current characteristics of the distributed inverter power supply under different fault types. Based on fault current characteristics, positive sequence, negative sequence and zero sequence branch coefficients of distance protection of the power distribution network are corrected, equivalent impedance of the phase-shifting transformer is combined, a setting impedance initial value of a second stage of distance protection is calculated, and a corresponding relation between the setting impedance initial value and the equivalent impedance of the phase-shifting transformer is established. The phase angle difference between the two sides of a closed-loop point of the power distribution network is monitored in real time, the tap position of the secondary side of the exciting transformer is dynamically adjusted, the equivalent impedance of the phase-shifting transformer is changed accordingly, the distance protection setting impedance value is updated in real time, self-adaptive setting of protection parameters is achieved, and the fault recognition precision and the protection reliability are improved.

According to a method to aid installation of large-scale BESS in a power network, a hyperparameter optimization engine generates a feasible configuration of BESS defined by location and sizing parameters subject to an installation constraint. A power system simulation engine conducts an energy market simulation for the power network with the generated configuration over a defined simulation horizon to determine a configuration value. The power system simulation engine comprises one or more subroutines characterizing the impact of the BESS on the market clearing mechanism, to compute an expected generation cost associated with the BESS. The configuration value is determined based on the expected generation cost and a total installation cost of the BESS. The hyperparameter optimization engine is iteratively executed to generate an updated configuration based on the configuration values of previous configurations, to determine a final configuration of BESS defined by a set of optimal location and sizing parameters.

The invention discloses an SVG parameter dynamic setting method and device, electronic equipment and a storage medium, which are used for solving the technical problems of incomplete consideration, low optimization efficiency, easiness in falling into a local optimal solution and poor expansibility when an objective function is constructed in the prior art. The method comprises the following steps: constructing a control model of the SVG, and determining a to-be-optimized parameter set of the control model; voltage response of the control model during transient simulation is considered, and a fitness function based on voltage recovery segmented penalty is constructed; based on the fitness function, performing parameter optimization on the to-be-optimized parameter set through particle swarm optimization to obtain an optimal parameter set; and taking the optimal parameter set as a control parameter set of the SVG in practical application.

The present invention belongs to the technical field of power electronic converters and discloses a medium-voltage distribution network flexible interconnection switch topology and control method. The medium-voltage distribution network flexible interconnection switch topology provided by the present invention includes three connected reactors L1, three connected reactors L3, two chain-type STATCOMs, two three-phase isolation transformers, two three-phase LC filters, two three-phase inverter circuits, and a DC port. Back-to-back three-phase converters are introduced at the ends of the chain-type STATCOMs of two feeders. Through the back-to-back three-phase converters, active power flow mutualization between the two medium-voltage chain-type STATCOMs, that is, between two different feeders, can be achieved. The present invention can achieve DC capacitor voltage balancing of the chain-type STATCOM submodules of the two feeders. Compared with the BTB-VSC commonly used in existing medium-voltage distribution network flexible interconnection demonstration projects, this solution has lower cost, simpler topology, easier control, and does not need to consider the active and reactive power decoupling issues between interconnected feeders, making it easy to promote and apply on a large scale.

The invention discloses a network construction type SVG (static var generator) control method based on data-driven optimal self-synchronization. Obtaining the capacitor voltage of the direct current side of the SVG and the actual voltage and the actual current of the grid-connected point; constructing a DeePC controller input according to the actual voltage of the grid-connected point, the SVG direct current side capacitor voltage and a preset reference value, and obtaining a frequency deviation through the processing of the DeePC controller; adding the frequency deviation and a power grid rated frequency to obtain a controller frequency, and integrating to obtain a modulation wave phase signal; according to the SVG output voltage reference value, the actual voltage is sequentially processed by a voltage outer loop, current amplitude limiting and current inner loop to obtain a modulation wave voltage amplitude signal; and processing the modulated wave phase signal to obtain a modulated wave signal. According to the method, the control sequence is optimized online by directly utilizing the voltage data collected in real time, the mismatching risk of a traditional model is avoided, and a reactive power support solution with better dynamic response and autonomous toughness is provided for a new energy power grid.

The invention discloses a control method and system for participation of a network construction energy storage type SVG in frequency modulation and voltage regulation of a power grid, and the method comprises the steps: constructing a second-order synchronous phase modifier model in a network construction energy storage type SVG control system, and generating a phase angle delta and an angular frequency omega; obtaining a frequency deviation according to the angular frequency omega and the grid-connected frequency omega ac; generating an internal voltage instruction value by adopting reactive power-voltage droop control according to the deviation between the grid-connected point voltage and the reference voltage; and according to the frequency deviation and the voltage deviation, a reactive-voltage droop coefficient and a virtual admittance parameter are adjusted in real time, a current reference value is generated by using the updated virtual admittance parameter, and finally voltage and frequency adjusting current is output through current decoupling and PWM driving. Under the condition of a weak power grid or a fault, the networking energy storage type SVG can stably generate voltage source characteristics without a phase-locked loop; and the energy storage unit can quickly release or absorb active power to realize efficient inertial support.

The invention discloses a hybrid distributed power flow controller topological structure and a control method thereof. The topological structure comprises a distribution network Sen transformer DST and a distributed static synchronous series compensator DSSC. The distribution network Sen transformer DST comprises a three-phase double-winding transformer and an on-load tap changer group; each phase of the three-phase double-winding transformer comprises a main winding and a secondary winding, the high-voltage end of the three-phase main winding is connected with the head end of the three-phase distribution line, the low-voltage end of the three-phase main winding is in star connection, and the neutral point of the three-phase main winding is grounded; the on-load voltage regulation switch group comprises six on-load voltage regulation switches which are respectively configured on the low-voltage side of the three-phase main winding and the three-phase secondary winding and provide three-phase first compensation voltage in a cross series connection mode; a distributed static synchronous series compensator DSSC provides a three-phase second compensation voltage; and the three-phase first compensation voltage and the three-phase second compensation voltage are superposed to synthesize a three-phase compensation voltage, and the three-phase compensation voltage is injected into a three-phase distribution line through a three-phase isolation transformer. The invention provides a series hybrid topology consisting of a DST (Digital Subscriber Terminal) and a DSSC (Digital Subscriber Subscriber Center).

The invention discloses an impedance-adjustable series hybrid cascade static synchronous compensator and a control method thereof. The method comprises the following steps: acquiring grid-connected point voltage and load current information, and performing positive and negative sequence component analysis on the grid-connected point voltage and load current information; calculating a compensation line current component with the same size and opposite phase as the positive and negative sequence components of the load current so as to compensate the reactive power and the negative sequence current of the grid-connected point load; zero-sequence injection current used for in-phase active power balance is calculated, and reference operation current of each cascade branch is obtained; calculating the output reactive power of each phase based on the cascade branch voltage of each phase and the reference operation current, calculating the corresponding trigger angle of each phase thyristor under the condition that the adjustable impedance bears all phase voltages and generates all reactive power, and generating a pulse control signal to realize the control of the adjustable impedance; and each phase cascade converter adopts quasi-proportional resonance control to track the reference operation current, and generates a corresponding PWM signal to respectively control each phase cascade converter.