1750results about "Electric power transfer ac network" patented technology

The invention discloses a method for improving the stability of a system for sending out deep and far sea wind through a dual-port light converter. The method comprises the following steps: introducing a voltage feed-forward path comprising a phase compensator and a low-pass filter into an MMC differential mode control loop in the dual-port light converter; and a compensator parameter feasible region is calculated based on the phase characteristics of the oscillation risk frequency band, and the cut-off frequency of the filter is set, so that targeted phase compensation and impedance remodeling are realized, and the damping of the dual-port light converter is effectively enhanced. According to the method, the impedance characteristic of the dual-port light-weight current converter in the oscillation risk frequency band is remarkably improved, and a reliable technical path is provided for improving the stability of the dual-port light-weight current converter.

The invention discloses an offshore wind power collecting and sending-out system and method based on a multi-port multi-frequency alternating current and direct current hybrid integrated platform, and belongs to the field of power transmission and distribution of power systems. The system comprises an intermediate-frequency, power-frequency and low-frequency wind power collection subsystem, an offshore integrated platform, a direct-current sending-out submarine cable, a low-frequency sending-out submarine cable, an onshore converter station and an onshore frequency conversion station. The various wind power collection subsystems respectively collect wind turbine generator group outputs with corresponding frequencies and send the wind turbine generator group outputs to the offshore integrated platform; the offshore integrated platform converts intermediate-frequency, power-frequency and partial low-frequency electric energy into direct current and then transmits the direct current to the onshore converter station through the direct-current sending-out submarine cable, and the converter station converts the direct current into power-frequency alternating current; and after being boosted, the other low-frequency electric energy is sent to a land frequency conversion station through a low-frequency sending-out submarine cable to be converted into power-frequency alternating current, so that efficient collection and grid-connected sending-out of multi-frequency wind power resources are realized. According to the invention, the problem that a plurality of independent platforms need to be built in a complex multi-point grid-connected scene in the prior art can be solved.

The invention discloses a multi-type networking equipment collaborative planning method for multi-scene composite regulation and control contribution, and the method comprises the following steps: calculating a single power flow sensitivity factor according to an interaction relation between branch power flow and node injection power; calculating an overload weight coefficient of each branch based on a multi-power flow blocking scene, calculating a power flow sensitivity factor under multiple scenes based on an interaction relationship between branch power flow and node injection power, and constructing a multi-scene composite regulation and control index; according to the multi-scene composite regulation and control index, selecting a plurality of access positions, and determining network construction type HVDC and network construction type energy storage grid-connected access positions; and according to the network construction type HVDC and the network construction type energy storage grid-connected access position, establishing a double-layer optimization model, and carrying out cooperative solution on the double-layer optimization model to obtain multi-type network construction equipment capacity optimization configuration under multiple scenes. According to the invention, the technical problems that the existing network construction equipment cannot be suitable for multi-scene composite regulation and control and dynamic tidal current congestion under multiple working conditions are solved.

The invention provides a series-parallel high-voltage direct-current power transmission system transient state control method suitable for sending-end alternating-current faults, and belongs to the technical field of power systems. The method comprises the following steps: constructing a direct-current power safe operation boundary of an LCC converter station by combining LCC rectification side safety constraint and LCC inversion side commutation failure risk constraint conditions; constructing a commutation failure suppression strategy model of VSC and LCC cooperative control; and by using the commutation failure suppression strategy model, after a sending end alternating current fault occurs and is eliminated, controlling and suppressing the commutation failure of an LCC inverter station by using a control strategy of VSC dynamic reactive compensation and LCC trigger angle adaptive adjustment cooperation, and completing commutation suppression of the series-parallel high-voltage direct-current power transmission system. According to the invention, the problem of commutation failure caused by a sending end alternating current fault intensified by the interaction influence of conventional high-voltage direct current and flexible direct current is solved.

The invention, which relates to the technical field of direct-current power transmission, discloses a co-offshore medium-high-frequency alternating-current offshore wind power full-direct-current collection system comprising: an offshore wind turbine module, which is used for obtaining offshore medium-voltage direct-current electric energy; the multi-port direct-current voltage transformation module is used for converting the offshore medium-voltage direct-current electric energy into offshore high-voltage direct-current electric energy; the direct-current submarine cable module is used for gathering the offshore high-voltage direct-current electric energy, acquiring the gathered offshore high-voltage direct-current electric energy and transmitting the gathered offshore high-voltage direct-current electric energy to the shore converter station module; the shore converter station module is used for acquiring shore high-voltage alternating-current electric energy according to the collected offshore high-voltage direct-current electric energy; the onshore alternating current module is used for receiving the onshore high-voltage alternating current electric energy and achieving full-direct-current collection of offshore wind power. By improving the medium voltage-high voltage direct current transformer topological structure and the control method, efficient and economical electric energy transmission is realized, the construction economy and the engineering application value of an open-sea wind power collection system are improved, and the average price and low price requirements of marketization development are met.

The invention belongs to the technical field of power transmission and distribution of a power system, and particularly discloses a DR-MMC alternating-current and direct-current hybrid grid-connected system single-pole grounding fault ride-through method. The DR-MMC alternating-current and direct-current hybrid grid-connected system is constructed based on an offshore alternating-current wind power plant, an alternating-current collection submarine cable, an offshore direct-current wind power plant, a direct-current collection submarine cable, an offshore converter station, a direct-current sending-out submarine cable and an onshore converter station, and a connecting transformer valve side winding of the onshore converter station adopts high-resistance grounding. Judging whether the direct-current submarine cable has a single-pole grounding fault or not; and reducing the voltage instruction value and the power instruction value under the condition that the single-pole grounding fault occurs in the direct-current submarine cable, so that the transmission power of the grid-connected system is maintained at the preset transmission power, and the voltage and the current of the grid-connected system are maintained in a safe range. For a DR-MMC alternating current and direct current hybrid grid-connected system single-pole grounding fault, efficient and reliable fault ride-through can be realized through the method and the device.

The invention discloses a global cooperative control method and system for unbalanced fault ride-through of a multi-terminal DC power grid, and the method comprises the steps: constructing a fault detection model based on the positive sequence voltage drop depth and the negative sequence voltage size of the AC side of each converter station, automatically judging an unbalanced fault, and carrying out the fault detection when the fault is detected. Calculating the maximum allowable active current based on a fault station unbalanced current control model to carry out current limiting control on the converter station; and carrying out output power adjustment on the DC voltage deviation of the non-fault station based on the non-fault station power cooperation model. Asymmetric fault ride-through is carried out by using a constrained and optimized current instruction generation algorithm, and the capacity of a converter is dynamically and accurately distributed and utilized in a limited manner, so that the voltage support capability of a fault alternating-current power grid is maximized, and globally optimized adaptive power distribution is realized; the power of the non-fault station is calculated and distributed in a centralized manner and is dynamically adjusted according to the real-time available capacity, so that the self-adaption and global optimization of the running state change of the power grid are realized, and the fault handling toughness and reliability of the power grid are improved.

The invention discloses a rapid pilot protection method for a flexible DC line, and the method comprises the steps: firstly collecting the positive and negative current data of the DC line in real time, calculating the current change rate, and starting protection if the current change rate exceeds a preset threshold value; locking a fault moment data window, and calculating an H distance of a positive and negative electrode current sequence based on a Hausdorff distance so as to distinguish an inter-electrode fault or a single-electrode fault; thirdly, calculating a fault current break variable sequence by using the current data in the data window to obtain a current included angle of the side; then, current included angle information of the two sides is interacted with an opposite-side protection device; calculating a product average value, namely a fault current included angle entropy, according to the current included angles on the two sides; and finally, by judging whether the included angle entropy is greater than an internal and external fault threshold value or not, accurately identifying an internal fault and triggering tripping, or judging the internal fault as an external fault. According to the method, millisecond-level rapid protection is realized through the current included angle characteristic quantity and the included angle entropy criterion, and the method has high transition resistance resistance and low communication synchronization requirements.

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.

A kind of power device parallel type power module and capacitor charging and discharging method, power module includes two or more than pressure type power device, the two or more than pressure type power device adopts the physical form of half bridge group string upper and lower parallel;The half bridge group string of the pressure type power device is connected in parallel by silicon pile composite busbar;Each power module is provided with pneumatic short-circuit switch, in the case of multiple power module series connection, the pneumatic short-circuit switch is connected in series with all DC capacitors, and charging and discharging is carried out through the ground loop of flexible AC transmission equipment AC, DC valve side;The pneumatic short-circuit switch is connected with gas driving pipeline, and the gas driving pipeline is connected with valve-based gas pressurizing device.The power module can effectively improve the capacity of flexible AC transmission equipment, so that it has short-time frequency modulation capacity output, provides technical scheme support for new power system construction, and guarantees system safety and stability;The provided capacitor charging and discharging method can improve maintenance efficiency and enhance product reliability.

The invention discloses a distributed emergency frequency control method based on multi-agent near-end strategy optimization. The method comprises the following steps: establishing a frequency response model representing frequency dynamic characteristics and physical constraints of a power system under disturbance; each emergency power support station and each low-frequency load shedding station in the power system are modeled as independent agents, a distributed multi-agent cooperative control model is constructed, each agent makes a decision based on a local observation vector, and the action output of the agent is a continuous power regulation variable. The cooperative control model has a global reward function including frequency security and control cost; performing centralized cooperative training on the cooperative control model based on a multi-agent near-end strategy optimization algorithm; on the basis of the trained strategy network of each intelligent agent, online distributed execution is carried out, in the online distributed execution process, each intelligent agent does not need to communicate with each other, each intelligent agent can obtain a better cooperative control strategy only based on local observation, and the engineering adaptability and robustness of emergency frequency control are remarkably enhanced.

A coordinated optimization method for VSC-HVDC Frequency Synchronization Control and primary frequency regulation of hydropower includes: obtaining optimal PI parameters of the VSC-HVDC Frequency Synchronization controller from a first layer output of a dual-layer optimization model for coordinated parameters of VSC-HVDC Frequency Synchronization and primary frequency regulation; and obtaining a target PID control parameters from a second layer output of the dual-layer optimization model. The coordinated optimization method further includes adjusting the optimal PI parameters of the synchronization controller based on the target selection range and updating the PID control parameters of the primary frequency regulation system of hydropower based on the target PID control parameters. This approach aims to address the challenge of balancing the frequency response speed between the VSC-HVDC synchronization system and the primary frequency regulation system of hydropower.

The invention discloses a flexible AC / DC hybrid power distribution network fault recovery optimization method and system based on multi-agent deep reinforcement learning, a computer device and a non-transient computer readable storage medium, and the method comprises the steps: firstly constructing an AC / DC power distribution network model considering the operation characteristics of a flexible switch and a voltage source converter; then, flexible equipment is modeled as an independent agent, a multi-agent training architecture is established, a composite reward function fusing a load recovery rate, voltage stability and operation safety is designed, and a mechanism combining centralized training and distributed execution is adopted to realize multi-point cooperative control between the flexible equipment; and finally, designing a recovery optimization process for rapid decision and control execution after the fault. The method can realize higher load recovery rate and better voltage control performance in various fault scenes, has the advantages of strong decision real-time performance, good system expandability, strong strategy generalization ability and the like, and is suitable for autonomous recovery and intelligent regulation and control of the novel flexible AC / DC hybrid power distribution network.

The invention provides a pure new energy large base network construction type equipment configuration method for direct current delivery through an island, and relates to the field of power grid planning, and the method comprises the steps: obtaining the multi-station short-circuit ratio condition of the boost transformer low-voltage side of a power generation unit of all new energy stations in a pure new energy large base, judging whether the short-circuit ratio condition meets a first preset condition or not, and according to a judgment result, determining whether the short-circuit ratio condition meets the first preset condition; selecting a corresponding new energy station to configure network energy storage, so as to enable the short-circuit ratio of multiple stations at the boost transformer low-voltage side of all power generation units to meet a first preset condition; obtaining an effective short-circuit ratio condition of the isolated island direct current, and configuring a network construction type SVG in the isolated island direct current, so that the effective short-circuit ratio of the isolated island direct current meets a second preset condition; and according to the configured networking type energy storage and the configured networking type SVG, forming a networking type equipment configuration scheme. According to the invention, the reasonable configuration of the network-forming type energy storage and the network-forming type SVG can be realized, and the power grid strength and the voltage supporting capability of the whole system are effectively improved.

The invention discloses a power regulation and control method and device for a multi-terminal flexible direct current system, and the method comprises the steps: traversing the current line power flow of each line in the multi-terminal flexible direct current system, and determining an overload channel line set and a normal channel line set; sorting the overload channel lines according to the overload rate of each line in the overload channel line set, and determining a target overload line; in combination with the normal channel line set, analyzing the sensitivity of the target overload line to each adjustable variable, giving out the comprehensive sensitivity corresponding to each adjustable variable, and determining a target adjustment variable and an adjustment value of the target adjustment variable from the adjustable variables; and based on the adjustment value of the target adjustment variable, regulating and controlling the multi-terminal flexible direct current system and updating the overload channel line set, and regulating and controlling the multi-terminal flexible direct current system and updating the overload channel line set in real time, so that the multi-terminal flexible direct current system achieves the effect that the direct current line is not overloaded while frequently adjusting the power of the converter station to optimize the alternating current power flow.

A control method for suppressing an overvoltage of the receiving end hybrid modular multilevel converter with full-bridge submodules and half-bridge submodules (F / HMMC) under the fault at the receiving-end alternating-current (AC) system of the hybrid high-voltage direct-current (HVDC) transmission system. After a short-circuit fault occurs in a receiving-end AC) system of the hybrid HVDC transmission system, an AC voltage drop is generated, and the effective voltage of the receiving-end AC bus at the current time is measured. Because the hybrid modular multilevel converter (MMC) is capable of actively decreasing the DC voltage for operation, on a premise of ensuring that its output current is always within a rated current range, a control manner of setting the reference DC voltage and making the reference DC voltage not greater than the effective voltage of the AC bus enables receiving end power to be sent out, thereby suppressing an overvoltage of the receiving-end F / HMMC.

The invention relates to a DC power transmission system oscillation suppression method based on a matrix passivity theory. The method comprises the following steps: firstly, establishing a converter admittance matrix under a frequency coupling effect; then, constructing a stability criterion of the direct-current power transmission system based on the admittance matrix of the converter in combination with a matrix passivity theory; and finally, based on the stability criterion of the direct-current power transmission system, adding active damping and passive damping, adjusting corresponding parameters, and suppressing medium-high frequency oscillation of the direct-current power transmission system. The method can solve the problem of dependence on power grid side impedance modeling, constructs the stability criterion of the DC power transmission system by directly analyzing the admittance matrix characteristics of the converter, adapts to the complex situation when the AC grid side operation condition changes, and can completely suppress the medium-high frequency oscillation of the DC power transmission system. An unstable interval of a direct current system is transferred to a high frequency band through active damping, strict stability of the direct current power transmission system in middle and high frequency bands is achieved through passive damping, and the strategy cost is reduced.

The invention discloses an improved flexible direct current fault control method for improving current differential protection adaptability, and belongs to the technical field of power system relay protection and new energy power generation system grid-connected control. The method comprises the following steps: detecting a voltage drop abrupt change signal and a negative sequence voltage signal of a flexible DC output end, and starting a control strategy when the signals are satisfied; detecting a terminal voltage signal and active power of a new energy sending-out terminal, and calculating a new energy side current phase angle and a power angle; calculating a flexible DC side current phase angle control value and a negative sequence dq axis current reference value based on the parameters; and controlling the flexible DC side to output a negative-sequence current corresponding to the negative-sequence dq-axis current reference value, so as to actively adjust the current phase of the flexible DC side, reduce the phase angle difference between the fault current of the flexible DC side and the fault current of the new energy side, and discriminate the internal and external faults of the region through traditional current differential protection. According to the invention, the degree of freedom is controlled and the current phase is adjusted by using the flexible direct-current side negative-sequence current to reduce the phase angle difference of the two sides, so that the problem that the current differential protection adaptability in the double-end weak feedback system is reduced is solved, additional hardware is not needed, and the power grid safety and the new energy stable grid connection are ensured.

The invention relates to the technical field of electric power systems, in particular to a low-voltage distribution network voltage treatment method based on multi-point flexible direct current interconnection, which breaks through an island operation mode of a transformer area by introducing a flexible interconnection mechanism into a low-voltage distribution network, and improves the reliability of the low-voltage distribution network. Linkage management of multi-region voltage is realized; the flexible direct-current converter is used for realizing quick and real-time adjustment of active and reactive bidirectional power among the nodes; a set of efficient, stable and extensible multi-node power balance control algorithm is constructed, distributed collaborative optimization is realized, and dependence on a central controller is avoided; on the premise of ensuring the stability of the system, the dynamic management of the low voltage out-of-limit problem and the improvement of the electric energy quality under the complex operation condition are realized.

The invention belongs to the related technical field of direct current power transmission of a power system, provides an active support control method and system suitable for an offshore wind power direct current delivery system, overcomes the defect that active power is borne by a hybrid MMC when a traditional flexible direct current system active support control strategy is transplanted to a DR-hybrid MMC topology, and particularly solves the problem that when the hybrid MMC runs at zero direct current voltage, the active power cannot be borne by the hybrid MMC. The hybrid MMC can be prevented from increasing the active power transmitted by the hybrid MMC, the rated capacity of the hybrid MMC is reduced, and the economic benefit of the system is improved. The frequency and voltage supporting capacity of the DR-hybrid MMC series topology direct current sending-out system for the receiving end power grid is effectively improved, and the stability of the power grid is enhanced in the scene that high-proportion new energy is connected into the power grid.

The invention provides an anti-countercurrent control system and method based on transformer area flexible direct current interconnection, belongs to the technical field of power distribution network and new energy fusion control, and is suitable for direct current flexible interconnection and green energy collaborative utilization of heterogeneous transformer areas such as expressways, parks and urban and rural fusion areas. The system comprises an energy route management module, a transformer area capacity marking module, an energy monitoring module, a flexible direct current interconnection scheduling module, an anti-countercurrent module and an intelligent scheduling strategy module, and the control method comprises the steps of initializing the state of a transformer area, collecting data in real time, judging redundant power and scheduling the redundant power to the transformer area without power generation / grid connection capacity, and executing an anti-countercurrent strategy. And parameters and strategies are optimized based on an intelligent self-learning mechanism. The method achieves the preferential local consumption of new energy, prevents power countercurrent, guarantees the safety of a power grid, improves the adaptability and economical efficiency of the system, and is adaptive to a complex multi-source distributed energy scene.

The invention provides a medium and low voltage flexible direct current interconnection scheduling method, and relates to the technical field of power distribution network scheduling, and the method comprises the steps: carrying out the feature weight correction of a first fault judgment result and a second fault judgment result according to a transient feature quantity, and obtaining the corrected fault positioning information; specific fault equipment is determined according to the corrected fault positioning information, and a fault token containing the available capacity of the specific fault equipment is generated; and obtaining a dynamic capacity boundary of the thermoelectric coupling constraint of the specific fault equipment, constructing a dynamic scheduling optimization model, and performing optimization scheduling on the specific fault equipment according to the dynamic scheduling optimization model. According to the method, the fault information is obtained through coupling backstepping and spectral decomposition, weight correction is carried out in combination with the transient characteristics in the current limiting mode, the fault token containing the available capacity is generated and participates in scheduling, unavailable equipment can be eliminated in time or participated in derating, and the power supply continuity of key loads is guaranteed.

A seamless switching method and device for network-oriented MMC-HVDC converter station construction and network following control, relates to the field of power system control technology, without changing the inner loop current control, by constructing a unified outer loop reference current and initializing the setting of phase angle and voltage amplitude, the continuity of output voltage power angle and amplitude in the control mode switching process is ensured. The technology can quickly respond to changes in grid conditions, avoiding system disturbance and instability caused by mode switching. Simulation results show that this technology effectively reduces the impact of control switching on the system, significantly improves the stability and reliability of the system, and is suitable for flexible HVDC transmission systems under various grid conditions, especially in weak grid access and frequency support scenarios.

The invention discloses a flexible direct-current power transmission system and a fault ride-through method and system thereof. The flexible direct-current power transmission system comprises a main control module, and a new energy sending-out system, an alternating-current energy consumption device, a sending-end converter, a direct-current circuit breaker, a receiving-end converter and a receiving-end alternating-current power grid which are connected in sequence, the direct current circuit breaker is deployed on a direct current power transmission line between the sending end converter and the receiving end converter, and the receiving end converter is a modular multi-level converter formed by cascading a plurality of half-bridge sub-modules with damping branches; the main control module is in communication connection with the half-bridge sub-modules, the direct-current circuit breaker and the alternating-current energy consumption device and used for controlling the damping branches of the half-bridge sub-modules in the running state, the direct-current circuit breaker and the alternating-current energy consumption device to act when a direct-current fault occurs so as to restrain direct current and adjust direct-current voltage to be within a set voltage range. Therefore, no-locking fault ride-through is completed. According to the invention, high-reliability and low-cost DC fault ride-through can be realized.

The invention discloses an LCC-HVDC operation range optimization method and system considering transient overvoltage constraint, and belongs to the field of power system automation. The method comprises the following steps: calculating the capacity of a matched capacitor based on the power system topology and the LCC-HVDC transmission power; carrying out load flow calculation in combination with a capacitor scheme, initializing equipment parameters, establishing a quasi-steady-state model of each equipment, and solving a quasi-steady state at the moment of maximum reactive power consumption during commutation failure; based on the model and the result, solving the quasi-steady state at the initial moment of the commutation failure recovery stage; and calculating the node voltage of the rectifier station, optimizing the LCC-HVDC power and equipment parameters along the gradient if the node voltage exceeds the limit, and iterating until the transient voltage safety is met, otherwise, determining that the current scheme is an operation scheme. The system comprises a corresponding function module and a data storage module. The method can be applied to an actual hybrid system, the transient overvoltage is accurately evaluated, the LCC-HVDC safety power range is determined, the power grid safety is guaranteed, and the new energy consumption efficiency is improved.

The invention discloses a multi-type resource participation power grid frequency modulation method based on a consistency algorithm, and the method comprises the steps: firstly constructing an improved frequency response model fusing distributed optical storage equipment, hydrogen storage and energy storage equipment and a DC flexible load, identifying system parameters, solving a multi-resource comprehensive adjustment coefficient, constructing a directed graph model, employing a grouping consistency algorithm, and obtaining a multi-type resource participation power grid frequency modulation model; the optimal adjustment coefficient of each resource is solved through distributed optimization of an augmented Lagrange function and a consistency index, and primary frequency modulation of a multi-type resource collaborative response system is driven. According to the multi-type resource participation power grid frequency modulation method based on the consistency algorithm, by driving a multi-type resource collaborative response system to perform primary frequency modulation, collaborative regulation and control of light storage, hydrogen storage and flexible load are realized, economy and operation constraints are considered through distributed optimization, and communication complexity is reduced through a clustering iteration mechanism; and the frequency stability of the high-proportion new energy power grid is obviously improved.

The invention discloses an interface method for a VSC direct current system mixed granularity model and an alternating current system electromechanical transient model. The method comprises the steps that a mixed granularity simulation framework is constructed, wherein an electromechanical transient phasor model is adopted on the alternating current side, and a simplified electromagnetic transient instantaneous value model considering electromagnetic characteristics is adopted on the direct current side; the VSC converter adopts a unified equivalent model, and various types of converters are adapted through parameter configuration; a low-voltage side bus of the converter transformer is arranged at the interface position of the simulation framework and the alternating current system; simulation and interaction rules are configured, wherein the simulation step length of each direct-current power grid is independently set; the alternating current system provides port voltage and alternating current control information for the simulation framework, the simulation framework is equivalent to the alternating current system as a power source, and power exchange is realized through the converter station; in one time step calculation of the electromechanical transient state, the simulation framework changes along with the alternating current side information, a historical simulation state is taken back, and direct current side simulation in the alternating current time step is carried out again until the power interaction deviation converges.

The invention discloses a hybrid cascade system commutation failure suppression method caused by sending end faults, and belongs to the technical field of high-voltage direct-current power transmission systems. The invention aims to provide the method for suppressing the commutation failure of the hybrid cascade system caused by the sending-end fault, which comprises the following steps of: monitoring the deviation between a direct current instruction value and an actual value in a system fault recovery period in real time, and dynamically adjusting a rectifier-side trigger angle instruction according to the deviation so as to control the direct current recovery rate and amplitude. According to the method, the dynamic recovery characteristic of the sending-end bus voltage and the constant direct-current voltage control effect of the inversion-side MMC are combined, and key influence factors of commutation failure are systematically analyzed; a commutation failure suppression strategy based on a rectification side additional trigger angle is provided. According to the method, the influence of the phase dynamic change of the alternating current bus voltage at the rectification side and the constant direct current voltage effect of the MMC at the inversion side on the commutation failure in the fault recovery process is fully considered, and reference is provided for safe and stable operation of the hybrid cascaded high-voltage direct current power transmission system.

The invention provides a method, device, apparatus, and storage medium for determining the overload boundary of MMC, which belongs to the field of DC transmission technology. The overload operation boundary of the MMC may be accurately determined, which is helpful to set the load level of the MMC reasonably in the design and operation process to ensure safe and efficient operation.

The invention discloses a wind-light storage configuration method considering transient voltage constraint and inertia constraint, and the method comprises the steps: obtaining a wind-light typical output scene and a direct-current power transmission plan power through employing a k-means clustering method based on wind-light output and receiving end load data, employing a bilevel programming model for wind-light-storage capacity configuration, and obtaining a wind-light storage capacity configuration model; the upper-layer model takes the minimization of the total investment cost as an optimization target, and constructs a transient overvoltage constraint, an inertia support constraint and a capacity constraint based on the short-circuit capacity; and the lower layer model takes the operation cost of the thermal power generating unit and the new energy power abandoning cost as targets, considers the power balance constraint, the operation constraint and the like of the wind-light-storage channel direct current power transmission delivery system, introduces the power transmission confidence probability constraint, and realizes the measurement of the delivery reliability of the wind-light storage channel. An improved grey wolf optimization algorithm is adopted, a Logistic-Tent mapping opposite learning mechanism is added, a mutation operator, a crossover operator and a selection operator are introduced in the differential mutation process of the algorithm, the population number and category richness in the algorithm are improved, and the solving speed is increased.