42results about "Flicker reduction in ac network" patented technology

This application provides a DC boost grid connection method, system, device, equipment, medium, and product, relating to the field of new energy grid connection. The method employs a cascaded topology of H-bridge modules to dynamically adjust the DC voltage output of the photovoltaic array according to the light intensity to match the light conditions. Simultaneously, it dynamically adjusts the number and switching times of the H-bridge modules based on the grid voltage demand, ensuring that the peak value of the multi-level AC voltage output by the adjusted H-bridge module group matches the voltage demand. Furthermore, it actively constrains the harmonic distortion rate and amplitude fluctuation rate of the output voltage to be below preset thresholds. Without requiring a power frequency boost transformer and a large-capacity inverter, it achieves direct boost grid connection from photovoltaic DC to high-voltage AC. It also solves the voltage distortion and amplitude fluctuation problems that easily occur during the dynamic adjustment of the number of modules, improving grid-connected power quality and system operational stability, and reducing the cost of the photovoltaic DC boost grid connection system.

Disclosed is a method for analyzing voltage stability based on a multi-swing characteristic of a voltage disturbance curve, including the following operations. A main server acquires a voltage disturbance curve of at least one node; and for each voltage disturbance curve, analyzes the voltage disturbance curve based on a multi-swing characteristic, to determine analysis time and a number of processing layers for curve wavelet package decomposition corresponding to the voltage disturbance curve. The main server establishes an analysis task for each node, and distributes the analysis task to at least one sub-server. For one of the at least one sub-server, based on the analysis time and a number of processing layers for curve wavelet package decomposition, a wavelet package analysis is performed on the voltage disturbance curve, to acquire a wavelet decomposition coefficient of each layer corresponding to the voltage disturbance curve. For the one of the at least one sub-server, according to the wavelet decomposition coefficient of each layer corresponding to the voltage disturbance curve, a characteristic value of each layer is determined. For the one of the at least one sub-server, according to the characteristic value and a characteristic threshold of each layer corresponding to the voltage disturbance curve, a voltage stability analysis result of the node is determined.

The application provides a magnetic resistance type dynamic voltage recovery device and method based on particle swarm optimization, relates to the technical field of dynamic voltage recovery devices, and through deep time sequence analysis on historical voltage drop, the amplitude and duration of voltage drop are dynamically predicted, so that the amplitude interval and duration of injected voltage are adaptively determined; a particle swarm algorithm is combined to perform multi-objective optimization on a control scheme, and the performance of an evaluation scheme is fed back, so that precise design and real-time adjustment of the injected voltage waveform are realized; a multi-scheme screening and switching mechanism effectively guarantees stable operation and safety of the system under abnormal working conditions, improves the intelligent level and compensation quality of the dynamic voltage recovery device as a whole, meets the requirements of rapid response and efficient compensation under a complex power grid environment, and enhances the stability and reliability of the system as a whole.

The application relates to a frequency control method for a thermal power plant based on a reinforcement learning algorithm, wherein the method comprises the following steps: obtaining primary frequency regulation evaluation data and current combined cycle unit working condition data to form state data; determining a state-action pair in a preset algorithm model, wherein the preset algorithm model is obtained by training a Q learning algorithm through reinforcement learning based on the state data of the thermal power plant; obtaining evaluation values of each state-action pair based on a preset estimation rule through the preset algorithm model, and obtaining a target state-action pair according to the evaluation values; generating a control instruction according to an environmental interaction action in the target state-action pair, and adjusting the output power and action time of an electric energy storage device through the control instruction. Through the application, the problem that the service life of an electric energy storage device of a combined cycle unit is low due to long-term high-load working state in the related art is solved, accurate frequency regulation control is realized, power waste of the electric energy storage device is reduced, and the service life of the electric energy storage device is improved.

Disclosed in the present application are an oscillation suppression system and oscillation suppression method for an electric power system. The oscillation suppression system comprises a hydrogen production and hydrogen storage apparatus mounted at a sending-end power generation unit in an electric power system and a power generation apparatus mounted at a receiving-end power generation unit in the electric power system, wherein power generation fuel of the power generation apparatus is from the hydrogen production and hydrogen storage apparatus; and when active power oscillation occurs in the electric power system, the hydrogen production and hydrogen storage apparatus and the power generation apparatus are put into operation, such that a decrease in active power, which is transmitted by the sending-end power generation unit, is kept equal to an increase in active power, which is transmitted by the receiving-end power generation unit. Therefore, there is no need to cut off grid-connected power generation units in turns when active power oscillation occurs in an electric power system, and oscillation suppression can be directly performed by means of a hydrogen production and hydrogen storage apparatus and a power generation apparatus, thereby maintaining high-permeability wind / light consumption.

The application provides a control method of an inertia adaptive based distributed energy system grid-connected inverter, and relates to the technical field of control of grid-connected inverters in distributed energy systems. The method comprises the following steps: collecting output voltage and output power of a virtual synchronous generator (VSG) in a distributed information energy system, and establishing a VSG model of a cascaded micro-grid in the distributed information energy system according to the collected data; determining a control strategy by using a distributed learning algorithm, and performing phase-locked loop control on the phase of the angular frequency of the VSG according to the control strategy, so as to obtain the load demand of the active power and the reactive power of the VSG; designing an adaptive virtual inertia control law according to the change process of the real-time angular frequency of the VSG, establishing an adaptive virtual inertia model of the VSG and designing a deviation term, so as to obtain an adaptive virtual inertia strategy. According to the method, the power grid state and the actual situation of the distributed information energy system are dynamically responded to the strategy, and the stability and response capability of the grid-connected inverter are improved.

The application provides a coupling power system stability control strategy collaborative control method, device, equipment and readable storage medium, which can be used for a stability control master station of a power system, especially a wide-area collaborative stability control master station. When multiple coupling stability control strategies exist in the power system, such as a stability control strategy triggered locally by the power system and a strategy for processing a remote control command simultaneously or sequentially exporting an action command in a short time and acting on the same group of controlled objects, the collaborative control of the multiple stability control strategies can be realized through a coordination mechanism independent of the stability control strategies, without changing the related strategies or changing other strategies after the partial strategies are updated, so as to reduce the under-tripping and over-tripping risks of the stability control master station of the power system when the coupling strategies exist, reduce the design difficulty of the stability control strategy collaborative control, reduce the mutual influence of the strategy and device updating, effectively realize that the total control amount result is controlled reasonably, and neither cause over-control nor cause loss of control, which harms the stability of the power system.

The present application relates to the field of doubly-fed wind turbine subsynchronous oscillation suppression, and particularly relates to a doubly-fed wind turbine subsynchronous oscillation suppression method based on online sequence impedance spectrum identification. The content includes: real-time acquisition of three-phase voltage and current analog signals of a doubly-fed wind turbine grid-connected point, and extraction of positive sequence voltage and current components; based on the positive sequence voltage and current components, frequency domain positive sequence impedance is obtained, a frequency domain positive sequence impedance spectrum is generated, and a subsynchronous oscillation frequency is extracted; based on the subsynchronous oscillation frequency, in combination with the frequency domain positive sequence impedance spectrum, a frequency compensation output control signal is calculated, a positive sequence impedance dynamic adjustment formula at the subsynchronous oscillation frequency point is constructed, and the dynamic adjustment amount of the positive sequence impedance at the subsynchronous oscillation frequency point is calculated. The problem that the traditional subsynchronous oscillation suppression method is difficult to accurately identify the subsynchronous oscillation frequency, cannot adapt to the oscillation characteristics of the low-frequency region of the doubly-fed wind turbine, cannot realize targeted and accurate suppression, and cannot meet the real-time control requirements of engineering is solved.

The application discloses a kind of stepwise regression primary frequency control method and system, the method includes: obtaining primary frequency power theoretical value, and setting regression coefficient;Record the maximum frequency modulation component when the process of primary frequency action;When frequency is in low frequency stage, again primary frequency is from the maximum frequency modulation component regression stage, with k*△Q as regression step, satisfy (1-n*k)*△Q≤△N<(1-(n-1)*k)*△Q, then actual unit real-time primary frequency component is (1-(n-1)*k)*△Q;When frequency is in high frequency stage, again primary frequency is from the maximum frequency modulation component regression stage, with k*△Q regression step, satisfy (1-n*k)*△Q≥△N>(1-(n-1)*k)*△Q, then actual unit real-time primary frequency component is (1-(n-1)*k)*△Q;Wherein,△N indicates primary frequency power theoretical value, k indicates regression coefficient;△Q indicates maximum frequency modulation component;N indicates the number of steps of stepwise regression. By the stepwise regression primary frequency control method and system disclosed in the application, the stability of primary frequency adjustment can be improved.

The application discloses an active island detection method of an energy storage grid-connected inverter, and relates to the technical field of safe operation of the energy storage grid-connected inverter, and aims to solve the problems of the existing passive detection method, such as a detection blind area, and the traditional active detection method, such as influence on power quality and high misjudgment rate. The method comprises the following steps: after initialization, only when the inverter is in a grid-connected mode, there is no high-priority fault, and a detection function is enabled, a low-intensity reactive disturbance that is adapted to current active power is injected; a power grid frequency is continuously collected and a difference value is calculated, if the difference value exceeds a deviation threshold value, a suspected island counting is increased, and the reactive disturbance is increased according to the counting value, after a predetermined number of times, the disturbance is cleared and the frequency response is waited; if the frequency jump and the disturbance direction are consistent and exceed a jump threshold value, an island confirmation counting is increased, if a predetermined number of times are reached, an island is determined and a grid-connected disconnect protection is triggered; and after the protection, a delay reset is performed. The application has no detection blind area, guarantees power quality, has low misjudgment rate, and is suitable for inverters of different power levels.

This invention discloses a coordinated control method for a sending-end bipolar converter in a wind power integrated into a flexible DC system, relating to the field of power system protection and control. The method includes the following steps: Step S1, setting the active power-frequency rise characteristic curve equations for the sending-end positive and negative converters; Step S2, setting the reactive power-voltage droop characteristic curve equations for the sending-end positive and negative converters; Step S3, setting the active power-frequency rise characteristic curves for the positive and negative converters under special operating conditions with limited capacity; Step S4, the active power balance and voltage stabilization adjustment process of the sending-end positive and negative converters during wind power output power fluctuations; Step S5, the frequency coordination process of the bipolar converters. This invention, employing the above-mentioned coordinated control method for a sending-end bipolar converter in a wind power integrated into a flexible DC system, can ensure the balance of active power between the positive and negative DC networks and the voltage and frequency stability of the AC bus voltage when there are control value data deviations in the control system.

The application discloses a grid-connected converter active damping control method and belongs to the field of converter control. The control method is characterized in that a first-order unstable digital filter is connected in series on a positive and negative feedback path of a capacitor voltage, a reasonable parameter is used for design, and a phase compensation characteristic of the filter is fully utilized to compensate for a phase lag introduced by digital control. The filter can guarantee the stability of the system and improve the robustness of the system in the case of nonlinear change of grid impedance inductance and weak grid, and the filter has few design parameters and a simple design process. The converter loop structure adopting the control method is simple, convenient to design, large in system stability margin, and suitable for three-phase LCL filter grid-connected / following grid type converter occasions.

The application discloses a coal-fired power generation and Carnot battery energy storage coupling system and an operation method thereof, and relates to the technical fields of coal-fired power generation and thermal energy storage. The system comprises a coal-fired power generation coupling storage tank system, a Carnot battery energy storage system and a Carnot battery energy release system. During a low electricity consumption valley, a coal-fired power generating unit maintains existing load unchanged, and redundant electric energy is input into the Carnot battery energy storage system through a motor, and finally, the electric energy is converted into heat energy of a heat storage medium and stored in different storage tanks. When electricity consumption peaks, the heat load of a boiler remains unchanged, the heat of a bypass feed water, newly added feed water and condensate water is used for heating, the output of the unit is improved, and the Carnot battery energy release system also generates part of electric energy by using the heat of the storage tank, and finally, the combined electric energy meets the electric load demand. The system can be expanded in a variable load range, and the efficiency of the variable load process can be ensured, the purpose of high efficiency and flexibility is achieved, and the system is an effective method for consumption of new energy and suppression of power grid fluctuation.

The application provides an offshore wind power-energy storage-vehicle network collaborative optimization method based on a wind speed probability scenario, and relates to the technical field of offshore wind power energy storage, wherein the method steps include obtaining wind speed data of an offshore wind farm and preprocessing; the wind speed data is decomposed into a trend component, a positive fluctuation component and a negative fluctuation component to construct a three-dimensional feature vector; the three-dimensional feature vector is subjected to probability clustering to generate multiple wind speed scenario parameters and scenario occurrence probabilities; an upper-layer multi-objective optimization model is constructed to obtain a power distribution strategy of the energy storage system between an electricity market and a frequency modulation auxiliary service market; a lower-layer two-stage joint clearing regulation model is constructed to perform joint clearing of the electricity market and the frequency modulation auxiliary service market, and the energy storage system is used for scenario-based adaptive frequency regulation; the market clearing and collaborative regulation results are fed back to the upper-layer multi-objective optimization model for evaluation to generate an optimal strategy, and a probability scenario-strategy mapping library is formed for calling.

The application provides a power electronic device inertia and primary frequency modulation coefficient estimation method, comprising: collecting unit, regional and system real-time data; inputting the unit, regional and system real-time data into a trained collaborative adaptive counter particle filtering module, and outputting a posterior particle set; the collaborative adaptive counter particle filtering module comprises an agent network and a particle transformation network; performing statistical operation on the posterior particle set to obtain a power electronic device inertia and primary frequency modulation coefficient estimation value. The method provided by the application can realize long-term, adaptive, point estimation and interval estimation of inertia and primary frequency modulation coefficient in a multi-level unit, region and system, solve the problems of model dependence and particle degradation of existing methods, and improve the robustness and engineering applicability of power electronic device dynamic parameter evaluation.

The application discloses a kind of electric heat storage frequency modulation peak regulation control system and control method thereof, the system includes electric heat storage system, turbine power generation system, electric heat storage power generation control system and peak regulation frequency modulation system;Electric heat storage system is connected with turbine power generation system, electric heat storage system is used to convert electric energy into heat energy, turbine power generation system is used to convert heat energy into electric energy;Electric heat storage system, turbine power generation system is connected with electric heat storage power generation control system respectively;Peak regulation frequency modulation system includes peak regulation frequency modulation switch device and peak regulation frequency modulation management control system, peak regulation frequency modulation switch device is electrically connected with the input end of electric heat storage system and the output end of turbine power generation system respectively, and peak regulation frequency modulation management control system is connected with peak regulation frequency modulation switch device, electric heat storage power generation control system, external power grid dispatching system communication respectively.The application is further expanded by setting peak regulation frequency modulation system, the range of on-grid load regulation, improve the response speed of system, better realize the flexibility of system peak regulation frequency modulation.

The application discloses a kind of quasi-linear demand response methods for realizing power transmission and distribution cooperation, comprising the following steps: step one, solving the system level load quasi-line of power transmission network;Step two, solving the node load quasi-line of power transmission network;Step three, solving the node load quasi-line of distribution network;In the step one, the principle of "adjustable" balance "unadjustable" is that: the power fluctuation caused by unadjustable resources can be quantified by the superposition of the predicted maximum output of renewable energy generation and rigid load, and based on this, the system level ideal load curve shape of DR load for relieving power fluctuation is formulated;The application defines the respective guide targets for the active distribution network of different positions, flexible load participating in large-scale demand response, realizes demand response under the cooperation of transmission and distribution, and is beneficial to improving the renewable energy consumption capacity of transmission and distribution network while alleviating congestion based on the method of carrying out demand response, and forms a win-win situation of transmission and distribution network.

The present application relates to the technical field of power system frequency control, and especially relates to a parameter threshold cooperative power support method and system of a grid-connected wind storage system, which comprises the following steps: when the system frequency deviation is less than the lower limit of the frequency threshold, determining that the disturbance is a small disturbance, and the energy storage module does not respond, and only the rotor maintains the stability of the direct current voltage; when the disturbance causes the frequency deviation of the wind storage system to be greater than the upper limit of the frequency threshold, determining that the disturbance is a large disturbance, and at this time, the rotor and the energy storage module jointly maintain the stability of the direct current voltage, and cooperative support on the direct current side is realized. The present application can reduce the charging and discharging times of the energy storage module on the basis of ensuring that the rotor speed does not fluctuate greatly, improve the service life of the energy storage module of the wind storage system, effectively maintain the stability of the power grid frequency, and ensure the economy of the grid-connected direct-drive wind storage system.

The present invention relates to the technical field of new energy. Disclosed is a distributed new-energy energy storage system, the system comprising a distributed energy storage module, a central control module and a communication module. The distributed energy storage module comprises a storage battery, a battery management unit and a control unit; the distributed energy storage module is deployed at different positions of a power grid; and the distributed energy storage module is used for storing electric energy and releasing the electric energy. The central control module comprises a data processing unit, a prediction unit and a scheduling unit; and the central control module is used for monitoring state parameters of the working state of the distributed energy storage module in real time, and on the basis of a pre-acquired power grid load and the power generation capacity of a new energy power generation device, controlling the working state of the distributed energy storage module. The communication module is used for constructing a communication link between the distributed energy storage module and the central control module. The present invention enhances the capability of power grids to cope with abrupt load changes, effectively improves the efficiency and flexibility of new energy power generation, and improves the penetration rate of renewable energy and the overall operation efficiency of power grids.

The application discloses a virtual power plant regulation capacity dynamic quantitative evaluation and multi-stage linkage closed-loop control method, and belongs to the technical field of power system operation and control. The steps comprise the following: constructing a dynamic capacity stereographic map based on heterogeneous resource physical parameters; decomposing a total power instruction into control primitives matched with a coordinated resource cluster and predicting risks; performing parallel safety deduction through a virtual power grid deduction environment and generating an instruction strategy package; issuing an instruction and monitoring execution deviation, triggering a traceability-collaborative compensation mechanism to suppress deviation and updating resource states. The application adopts the construction of a dynamic capacity stereographic map for accurate evaluation, generates an instruction strategy package in combination with virtual deduction for safe pre-control, and uses a traceability-collaborative compensation mechanism for stable closed-loop collaborative control strategy, which can change power grid safety risks from passive response to proactive prevention in advance, improve the accuracy, safety and stability of virtual power plant regulation, and effectively suppress control oscillation caused by disordered response of a large number of heterogeneous resources.