91results about How to "Improve FM capability" patented technology

The invention discloses an inertial frequency-modulation drive rotating speed protection control system and method for a doubly-fed wind turbine. A wind speed detection module collects the wind speed, the rotating speed of a fan and the pitch angle parameter. According to a rotating speed protection control link, the real-time captured mechanical wind power of the fan is computed according to information collected by the wind speed detection module, and a loss computing module is connected with the rotating speed protection control link, the loss is subtracted from the real-time captured mechanical wind power; and the obtained computing result is compared with electromagnetic power output by a generator, an input and output power difference caused when the doubly-fed wind turbine participates in system frequency modulation is obtained, the input and output power difference is transmitted to a proportional link and an integration link through a trigger switch, the negative feedback power control quantity is output after the proportional link and the integration link act, and the negative feedback control quantity and an inertial frequency-modulation control signal jointly serve as a frequency modulation additional active power given value. By means of the inertial frequency-modulation drive rotating speed protection control system and method, secondary impact on the system frequency when the doubly-fed wind turbine exits from the frequency modulation can be avoided, and the problem that the power loss is large due to that fact that the rotating speed in the constant rotating speed region is overly lowered is solved.

The invention provides a variable speed wind turbine generator frequency control method based on dynamic standby power. The method comprises the following steps that I, a frequency modulation operation strategy of a variable speed wind turbine generator is determined according to operation conditions of the variable speed wind turbine generator; II, whether the variable speed wind turbine generator participates in system frequency modulation or not is judged; III, whether the rotating speed of the wind turbine generator is out of limit or not is judged; IV, an active frequency control module is activated, and an active power set value of the wind turbine generator is modified; V, control over the system frequency is achieved. The variable speed wind turbine generator frequency control method based on dynamic standby power can achieve frequency modulation capability of the wind turbine generator in a full wind speed region, when participating in the system frequency modulation to provide active support, the wind turbine generator is not affected by the operation conditions, and therefore electric system frequency stability is improved.

The invention discloses a main steam pressure change-based thermal power generating unit load control method, which comprises the following specific implementation steps of: (1) taking unit given load as pure proportional steam turbine master control proportion feed-forward input quantity through a proportional component; (2) taking the unit given load as steam turbine master control differential feed-forward input quantity; and (3) summing unit given load dynamic results generated by the step (1) and the step (2) through the proportional element and a differential element respectively and providing to the steam turbine master control PID (Proportion Integration Differentiation) regulating step as feed-forward FF input quantity. The main steam pressure change-based thermal power generating unit load control method has the beneficial effects that the control problems of quick response and the like when the thermal power generating unit is put in the AGC (Automatic Generation Control) mode can be solved through implementation, the requirement of a power grid on the unit AGC can be effectively met, and the requirements of frequency modulation and peak regulation are met.

The invention discloses a virtual double-fed induction generator inertia control method coordinated with secondary frequency regulation, which solves the problem of cooperation between the virtual inertia control of a wind turbine generator and the secondary frequency regulation of a power system. On the basis of an original virtual inertia control module, a module which is coordinated with the secondary frequency regulation of a power system is added, so that the overall frequency regulation effect is increased. Moreover, in the added module, the rotational speed of the rotor of the wind turbine generator is considered, so that the wind turbine generator can continuously operate within a safe rotational speed range; the problem of the affection of system frequency fluctuation on the active regulation capability of the wind turbine generator is solved; because the affection of system frequency fluctuation on the active regulation capability of the wind turbine generator is great, in order to ensure that the double-fed induction generator has better frequency regulation capability, the steady-state frequency response of the wind turbine generator is optimized, and moreover, accordingly, a control strategy is designed, so that the frequency regulation effect of the wind turbine generator is increased to a certain degree.

The invention relates to a wind and diesel microgrid frequency modulation control method with double-fed fan participation of load disturbance. The method comprises the following steps of designing an observer to carry out real-time estimation on load disturbance in a microgrid, distributing an estimation value to a double-fed fan and a diesel engine according to a proportion, and combining a traditional inertia strategy to control active output of the double-fed fan; additionally arranging a rotating speed recovery module; and according to a microgrid frequency deviation and power of the double-fed fan, designing a starting condition of the rotating speed recovery module, and after a frequency is recovered to be stable, starting the rotating speed recovery module so that a rotating speed is accelerated and is recovered to a level before frequency modulation. A frequency modulation capability of a double-fed fan participated in the microgrid is increased, a response capability of the microgrid to the load disturbance is enhanced and simultaneously a rotating speed recovery process is optimized.

The invention relates to a combination optimizing method, considering dynamic frequency constraint, for an isolated power grid set comprising a high-permeability photovoltaic power supply. Dynamic frequency characteristic constraint is taken into consideration in a set combination optimizing model, and the load of a photovoltaic power supply is reduced and the frequency modulation capability of a system is enhanced if the photovoltaic power supply participates in frequency modulation. The method is based on an expression of the lowest point of dynamic frequency after an isolated power grid containing frequency modulation of the photovoltaic power supply, and the invention discloses an expression about the lowest point of dynamic frequency when the smallest frequency modulation capacity is needed by frequency modulation participation of the photovoltaic power supply to determine that the set combination model has the sufficient but not excessive photovoltaic power frequency modulation capacity during optimization. Moreover, the set combination optimizing model that contains the lowest point of dynamic frequency and the photovoltaic power frequency modulation capacity constraint is established. The invention brings forward the method for optimizing the inner layer and the outer layer of the optimizing model on the basis of decomposition to generate optimizing segments and through Benders decomposition. The problem-solving complexity is effectively reduced.

The invention provides a micro power grid hybrid energy storage coordinative frequency modulation method. A micro power grid comprises hybrid energy storage equipment. The hybrid energy storage equipment at least comprises energy storage devices from a first type to a third type. The method comprises the steps of: obtaining total power, which needs to be emitted or absorbed by the hybrid energy storage equipment, according to a current voltage frequency of an alternating current bus in the micro power grid and a frequency reference value; and utilizing a preset low-pass filter and high-pass filter to carrying out distribution on the total power which needs to be emitted or absorbed by the hybrid energy storage equipment, wherein first power distributed by the low-pass filter is emitted or absorbed by the first type of energy storage device, residual second power after the distribution of the low-pass filter and the high-pass filter is emitted or absorbed by the second type of energy storage device, and third power distributed by the high-pass filter is emitted or absorbed by the third type of energy storage device. By adopting the method, the energy storage devices of different types are uniformly managed and are applied to a micro power grid system for carrying out micro power grid frequency modulation, so that the stability of the frequency of the micro power grid system is realized.

The invention discloses a primary frequency modulation online self-tuning controller and control system for a generator set and a method of the primary frequency modulation online self-tuning control system for the generator set, wherein the controller comprises a power network frequency deviation calculation module used for obtaining deviation between power network real-time operation frequency and power network reference frequency to obtain network frequency deviation, a frequency modulation compensation command function F(x) module used for calculating a primary frequency modulation load compensation command function F(x) of the generator set according to the network frequency deviation and set revolving speed diversity factors, and sending the primary frequency modulation load compensation command function F(x) of the generator set to a self-calibration algorithm control module and a command correction MUL module respectively, the self-calibration algorithm control module used for calculating a primary frequency modulation command correction coefficient and the command correction MUL module used for receiving the primary frequency modulation correction coefficient output by the self-calibration algorithm control module, and correcting the primary frequency modulation load compensation command function F(x) of the generator set to obtain a primary frequency modulation actual motion compensation command of the set, and finally sending the primary frequency modulation actual motion compensation command of the set to a set load control system.

The invention relates to a method for selecting frequency control parameters of a doubly-fed fan in a microgrid. The method comprises the steps of determining that a wind turbine generator and a diesel engine participate in a microgrid frequency control strategy in an island mode in common and building a small signal analysis model; and researching characteristic value change trajectories of the microgrid when parameters of a speed regulator of the diesel engine change, finding out a group of typical characteristic roots of reflecting dynamic frequency response characteristics of the microgrid, analyzing the change trajectory rule of obtained typical characteristic values when over-speed control and virtual inertia control parameters of a DFIG change, judging a frequency stability change of the microgrid according to the characteristic value trajectories, obtaining reasonable ranges of over-speed control and virtual inertia control coefficient values of the DFIG and improving PI control parameters. Therefore, the frequency oscillation phenomenon when the over-speed control and virtual inertia control coefficient values exceed the range can be avoided, the ranges of the over-speed control and virtual inertia control coefficient values are expanded, that is to say, a stability margin of the microgrid is increased, and the small interference stability of the microgrid is further strengthened.

The invention discloses a coordination control method for a wind turbine generator set participating in the automatic power generation control of a power system, and the method comprises the steps that a wind power plant transmits the ultrashort term predicted values of real-time power output and wind power output of the wind turbine generator set to a provincial dispatching center; the provincial dispatching center calculates the adjustment capacity and creep speed of the wind turbine generator set, capable of participating in the automatic power generation control, in an administrative region; a regional dispatching center employs model prediction to control and calculate the adjustment power of the wind turbine generator set and a conventional set; the provincial dispatching center distributes the adjustment power according to a proportion; and the wind power plant adjusts the wind active power output through a wind power plant AGC system. The method is advantageous in that the method effectively evaluates the adjustment capacity and performance of the wind turbine generator set participating in the automatic power generation control of the power system through the mutual coordination of the regional dispatching center, the provincial dispatching center and the wind power plant; the method gives full consideration to the operation characteristics and adjustment capabilities of various types of frequency modulation resources in the power system; the method achieves a purpose that the wind turbine generator set participates the automatic power generation control of the power system; and the method improves the stability and economics of a system.

The invention discloses a multi-model predictive control design method for a supercritical thermal power generating unit coordination control system based on a spatial metric algorithm, is used for controlling a supercritical coal-fired unit machine-furnace coordination system, and belongs to the field of thermal power engineering and automatic control. At present, machine-furnace coordination control systems of most power plants are designed based on conventional PID; during large-range variable-working-condition operation, performance of the coordinated control system is degraded due to thecharacteristics of large hysteresis, nonlinearity and time variation of a machine-furnace coordinated controlled object, so that the problems of low load regulation rate, poor precision, large main steam pressure and steam temperature fluctuation and the like of a unit in the operation process are caused. According to the invention, the traditional predictive control is properly simplified to realize the simplified design of linear predictive control; secondly, specific sub-model selection is realized in combination with a space measurement algorithm; and finally, a weighted soft switching strategy with simple calculation is provided for the integration of a plurality of sub-controllers, so that load regulation performance of a 660MW unit and operation stability of the unit can be remarkably improved, and the engineering requirements are met.

The invention discloses an energy management device and system for assisting frequency modulation of a thermal power generating unit by flywheel hybrid lithium battery energy storage. In one embodiment of the invention, the energy management device for assisting the thermal power generating unit frequency modulation through flywheel hybrid lithium battery energy storage comprises a data acquisition and monitoring module configured to communicate with an energy storage frequency modulation control device through a special protocol, acquire controller data and perform real-time monitoring operation, and acquire operating state data of an energy storage system and a unit; and a frequency modulation control module configured to automatically perform calculation based on a system working condition according to an AGC instruction, obtain a real-time energy storage output requirement, generate a corresponding output instruction and issue the output instruction to a lithium battery energy storage system and a flywheel energy storage system in real time so as to control the output of the energy storage system. According to the embodiment of the invention, the functions of the energy storagesystem in actual operation are perfected, the requirements of thermal power frequency modulation are met, and the reliability, the efficiency, the frequency modulation performance and the like of a hybrid energy storage combined thermal power frequency modulation system can be effectively improved.

The invention discloses a method for allowing a permanent magnetic direct drive wind power generation system to participate in frequency adjustment of a power grid on the basis of fuzzy control. A permanent magnetic direct drive wind power unit can change frequency adjustment power output by the permanent magnetic direct drive wind power unit according to real-time frequency of the power grid through coordination control over a motor side convertor, a power grid side convertor and a flywheel energy storage unit side convertor. The method has the advantages that maximum wind power tracking control can be achieved while auxiliary frequency adjustment power is provided for the power grid; control parameters of the power grid can be flexibly changed under all working conditions according to power grid frequency conditions, equivalent inertia and damping of the system can be dynamically adjusted, and the permanent magnetic direct drive wind power unit can participate in frequency adjustment of the power grid to the maximum degree.

The invention relates to a once-through boiler, steam turbine and power grid coordinated control method for primary frequency modulation analysis. The invention aims to solve a problem that characteristics of the boiler are not considered in the prior art so that great resistance is brought to participation of a high-capacity high-parameter thermal power generation unit in primary frequency modulation and safe and stable running of an electric power system is not facilitated. The method comprises the steps of firstly, performing once-through boiler energy state analysis so as to determine the once-through boiler energy state; secondly, performing power grid energy state analysis so as to determine the power grid energy state; and thirdly, determining a grid source energy coordinated control strategy according to the once-through boiler energy state determined in the step one and the power grid energy state determined in the step two. The once-through boiler, steam turbine and power grid coordinated control method enables the thermal power generation unit to not only sufficiently participate in frequency modulation, but also be operate safely and efficiently under the premise of meeting a requirement of safe running of a power grid. The once-through boiler, steam turbine and power grid coordinated control method is applied to the field of primary frequency modulation analysis.

The invention discloses a liquefied air energy storage system. The liquefied air energy storage system comprises an energy storage unit, a liquidation unit, a liquid storage unit storing a liquid-state working medium, a gasification unit and an energy release unit, wherein the energy storage unit comprises a compression device, a first heat exchanger and a cooler which are sequentially connected;the energy release unit comprises an expansion unit and a second heat exchanger which are sequentially connected; the liquidation unit comprises a liquidation device with an inlet end which communicates with an outlet end of the cooler; the gasification unit comprises an evaporation device with an outlet end which communicates with an inlet end of the second heat exchanger; the liquid storage unitcomprises a liquid storage device connected between the liquidation unit and the evaporation device; a gas buffer device is further communicated between the evaporation device and the second heat exchanger; and a gas-state working medium generated in the evaporation device is temporarily stored in the gas buffer device and then enters the second heat exchanger. The gas buffer device is arranged between the evaporation device and the second heat exchanger, so that a response time in a process of adjusting output frequency of the liquefied air energy storage system can be shortened, and the frequency adjustment performance of the liquefied air energy storage system is improved.

The invention discloses a coal-fired unit coordination control method and system. The method comprises the steps that proportional adjustment is conducted according to a boiler heat signal and the current fuel quantity, and a proportional adjustment result is obtained; integral adjustment is conducted according to a coal-fired unit load instruction and a pressure deviation signal, and an integraladjustment result is obtained; boiler coordination control is carried out according to a boiler heat signal, a turbine energy demand signal, the proportional adjustment result and the integral adjustment result; a variable load rate correction coefficient is determined according to the actual value of the main steam pressure of a coal-fired unit and the sliding pressure instruction of the coal-fired unit; the variable load rate set value is corrected according to the variable load rate correction coefficient to obtain a corrected variable load rate; a coal-fired unit load regulator set value is determined according to the corrected variable load rate and the coal-fired unit load instruction; machine coordination control is carried out according to the set value of the load regulator of thecoal-fired unit and the actual load. The method has the advantages of being capable of guaranteeing deep regulation of the load in the load changing process of the coal-fired unit and improving regulation quality.

The invention relates to a hybrid energy storage system energy management method for AGC frequency modulation in combination with a thermal power generating unit. A hybrid energy storage system is constructed through a flywheel and a lithium battery for the defects that the thermal power generating unit is weak in AGC instruction response capability and is high in randomness, and a random model prediction control method based on the Markov chain is provided for energy management of the hybrid energy storage system. The method comprises the following steps of 1) modeling future power requirements of the hybrid energy storage system by adopting the Markov chain according to historical data of a thermal power generating unit in response to an AGC instruction, 2) selecting future power requirements of the hybrid energy storage system by generating a scene tree. and 3) adopting random model predictive control to obtain respective compensation power of the flywheel and the lithium battery. According to the method, based on historical unit power response characteristic data of the thermal power unit, the performance indexes (KP values in two rules) of the thermal power unit can be improved, meanwhile, the respective output power of the flywheel and the lithium ion battery can be reasonably controlled, SOC fluctuation and power fluctuation of the flywheel and the lithium ion battery are reduced, and the energy storage life is prolonged.

The invention discloses an optimal bidding method and system for wind storage joint participation in an energy-frequency modulation market. The bidding method comprises the steps of obtaining predicted output and energy storage capacity of a wind power plant in each transaction time period, and clearing prices of the energy market and the frequency modulation market; substituting the predicted output and the energy storage capacity of the wind power plant in each transaction period and the clearing prices of the energy market and the frequency modulation market into a pre-constructed electricity market bidding model for calculation to obtain the capacity of wind power and / or energy storage participating in each scene; wherein the scene comprises a wind power participation energy market, anenergy storage participation energy market, a wind storage joint participation frequency modulation market and an energy storage participation frequency modulation market; wherein the electricity market bidding model is constructed by taking the optimal income when wind power and / or energy storage participates in each scene as a target. According to the invention, the frequency modulation performance of wind power is effectively improved, and the energy storage loss cost is reduced to a certain extent.

The invention discloses a gas turbine and liquid compressed air energy storage coupling system and method adopting continuous detonation. The gas turbine and liquid compressed air energy storage coupling system comprises a liquid compressed air energy storage system and a gas-steam combined circulation system. Through the multi-coupling of the liquid compressed air energy storage system and the gas-steam combined circulation system, an air compressor is driven by a motor powered by a power grid, heat in the energy storage compression process is stored by a heat conduction oil heat storage tank, heat absorbed in the energy release expansion process is provided by high-temperature heat conduction oil, and released supercritical compressed air is used as fuel air of a gas turbine, dilution air and intake air of an air turbine. Air compressor and turbine decoupling is achieved, the gradient utilization degree of high-temperature exhaust heat of the gas turbine is improved, the operation efficiency of an energy storage peak regulation system is improved, and the overall peak regulation capacity of the system is increased.

An electrochemical and flywheel hybrid energy storage system comprises an electrochemical energy storage device, a battery management system, a flywheel energy storage device, a flywheel control system, an energy storage energy management system, an energy storage auxiliary frequency modulation control device group, a bidirectional converter group and a transformer group. The device of the power plant unit combined with the electrochemical and flywheel hybrid energy storage system comprises the power plant unit and the electrochemical and flywheel hybrid energy storage system. The power plant unit is combined with the electrochemical and flywheel hybrid energy storage system, the electrochemical energy storage device and the flywheel energy storage device are preferentially controlled to perform corresponding actions when a power grid needs to be subjected to load increasing / decreasing frequency modulation, and the system has the advantages of high regulation speed, short response time and high regulation precision; and the electrochemical energy storage device and the flywheel energy storage device can quickly supplement or absorb the part of energy to maintain the stable bus voltage and ensure the safe operation of a high plant transformer.

The invention provides a fire storage system and an energy storage system AGC frequency modulation method and device. The method comprises steps that when the fire storage system is in an automatic power generation control AGC frequency modulation mode, firstly, a frequency modulation power command and a state of charge SOC of an energy storage system in the fire storage system are obtained; secondly, according to the FM power command and the SOC, the state relationship between the FM power command and the SOC is determined; thirdly, according to the state relationship, the corresponding frequency modulation strategy is formulated; the frequency modulation strategy includes repair strategy, the repair strategy is as follows, when the state relationship is out of the intervention control scope and the FM power command is within the positive dead scope, the energy storage system is controlled for performing forward operation till the SOC transforms to a corresponding near limit value ofthe ideal scope; the SOC of the energy storage system is made to tend to an ideal scope, SOC deviation of the energy storage system is avoided, moreover, the frequency modulation algorithm of the energy storage system is guaranteed to be effective, that is, the energy storage system effectively assists a thermal power unit to complete an AGC frequency modulation task, and AGC FM performance is improved.

The invention discloses an electric power frequency modulation market transaction clearing and settlement method, device and system, and the method comprises the steps of optimizing a frequency modulation auxiliary service, electric energy and a standby auxiliary service based on the frequency modulation information, frequency modulation capacity demands and frequency modulation mileage demands declared by all market main bodies, and obtaining a day-ahead frequency modulation plan; clearing the frequency modulation auxiliary service to obtain a rolling frequency modulation plan based on the day-ahead frequency modulation plan and the frequency modulation information of rolling updating of the market main body participating in frequency modulation in the day-ahead frequency modulation plan;clearing the electric energy and the standby auxiliary service, and clearing the frequency modulation auxiliary service to obtain a real-time frequency modulation plan according to the real-time market demand and the frequency modulation information of rolling updating of the market main body participating in frequency modulation in the rolling frequency modulation plan; and settling frequency modulation income based on the real-time frequency modulation plan. Rolling frequency modulation is introduced so that the scheduling mechanism is enabled to properly adjust the day-ahead frequency modulation plan, the rolling frequency modulation plan can be generated, the real-time frequency modulation plan can be acquired based on the rolling frequency modulation plan, and safety and stability ofthe power grid can be enhanced.

The invention provides a multi-time-space layering comprehensive frequency modulation control system based on a fan cluster. According to the multi-time-space layering comprehensive frequency modulation control system, firstly, different frequency modulation modes and participation time sequences can be adopted for draught fans at different wind speeds according to different running states of the draught fans at different wind speeds; secondly, aiming at the influence of wind speed on fan frequency modulation control, a clustering method considering the wake flow effect of the wind power plant is established, so that the number of units in each cluster can be distributed in a balanced manner, the overall frequency modulation effect of the wind power plant is improved, and the problem of secondary frequency fluctuation is avoided; and finally, considering the randomness of the wind speed, the wind power plant cluster is optimized in a rolling manner per minute by adopting MPC, thereby ensuring the optimal frequency modulation capability and frequency modulation accuracy of the wind power plant.

The invention discloses an Internet of Things signal state indicating circuit of an Internet of Things home appliance. The Internet of Things signal state indicating circuit comprises a frequency collection circuit, a frequency modulation loop, a comparison and amplification circuit and an indicating circuit, the frequency collection circuit collects the frequency of an Internet of Things signal when the Internet of Things of the Internet of Things home appliance is used, the frequency modulation loop performs composite circuit frequency selection on a frequency signal by using triodes Q1, Q2,a capacitor C3 and an adjustable resistor R5, the size of level of an output signal of the frequency modulation loop can be adjusted by adjusting the resistance of the adjustable resistor R5, the output signal of the frequency modulation loop is separately input to an in-phase input end and an inverting input end of an operational amplifier AR3 by the comparison and amplification circuit by usingoperational amplifiers AR1 and AR2 for comparison and amplification, the output signal of the comparison and amplification circuit is used as a driving signal of the indicating circuit to control thelevel-by-level conduction of triodes Q3 and Q4, when the Internet of Things function of the Internet of Things home appliance is used, the condition of the Internet of Things signal is judged throughthe number of turned on indicator lamps LED1 to LED3, and the effect of detecting the Internet of Things function of the Internet of Things home appliance in real time is achieved.

The invention discloses a thermal power generating unit peak load and frequency regulation system and method based on liquid compressed air energy storage. The system comprises a coal-fired power generating unit, a liquid compressed air energy storage system and a liquid compressed air energy release system. The liquid compressed air energy storage system and thermal power generating unit steam-water thermodynamic cycle are subjected to multiple coupling, a compressor is driven by a straight condensing turbine with admission steam and exhaust steam of a thermal power generating unit medium-pressure cylinder as heat sources, heat in the energy storage compression process is used for heating condensed water so as to squeeze low-pressure cylinder regenerative extraction steam, and heat absorption in the energy release expansion process is provided by high-temperature water supply. According to the system operation mode for improving the peak load and frequency regulation capacity, space-time transfer of part of energy of thermal power generating unit steam-water thermodynamic cycle can be achieved, and the peak load and frequency regulation capacity of the thermal power generating unit participating in a power grid can be improved. The thermal power generating unit peak load and frequency regulation system is suitable for all thermal power generating units and has the universalitycondition of large-scale popularization.

The invention discloses a frequency oscillation control method and system for a water-light complementary system under an off-grid condition. The method comprises the steps: obtaining a photovoltaic output level and a scheduling adjustment instruction of a system in real time, and determining the photovoltaic adjustable capacity; and selecting different frequency oscillation suppression schemes according to the photovoltaic adjustable capacity. According to the photovoltaic output condition and the adjustable capacity, complementation of water and electricity and photovoltaic is achieved on the real-time control level, the frequency stability level of the system is improved as much as possible on the premise that frequency oscillation damping suppression is achieved, and the frequency modulation capacity of the system is improved.

The invention relates to a back-to-back direct current transmission system based on a virtual synchronous machine and a control method thereof. The system comprises two inverters directly connected tothe direct current side. The difference between the collected actual direct current voltage and the set direct current voltage command is regulated by a regulator to generate a first power difference. Inverting the second mechanical power for active power regulation in the virtual synchronous machine control mode of the second converter, and summed with the first power difference, a first mechanical power which performs active power regulation in a virtual synchronous machine control mode as a first converter, First, the second mechanical power is used for generating the electric angle of thealternating current of the first and second converters. The back-to-back HVDC transmission system based on the virtual synchronous machine technology of the invention can effectively improve the frequency modulation capability of the system and ensure the safe and stable operation of the electric power system under the condition that the installed capacity demand of the generator set is reduced and the equivalent rotational inertia of the electric network is reduced.

A Kalman filtering control method for an electrolytic aluminum load to participate in frequency modulation of a power system comprises the following steps: step 1, establishing a transfer function between an electrolytic aluminum load reference control signal and actual output power based on working characteristics of the electrolytic aluminum load; 2, on the basis of the electrolytic aluminum load transfer function established in the step 1, establishing a frequency response model considering the electrolytic aluminum load, and obtaining a differential form expression of a kinetic equation of a system; 3, on the basis of the differential form expression of the kinetic equation of the system obtained in the step 2, Kalman filtering is used for processing measurement signal errors; 4, on the basis of the frequency deviation obtained through Kalman filtering, a fuzzy controller is adopted to control the power consumption of the electrolytic aluminum load. The invention designs a frequency estimation method based on Kalman filtering aiming at the problem of frequency measurement error of load side frequency measurement, and aims to improve the performance of electrolytic aluminum load participating in frequency control of a power system.

The invention discloses a fire-storage AGC frequency modulation control method by considering flexible load characteristics. The method is characterized in that partition control is carried out on theoperation of each frequency modulation resource, the operation constraint of a battery energy storage system and the centralized control constraint of a flexible load are designed from the perspective of source-load interaction, and the real-time condition of the system is accurately and reasonably adjusted based on frequency deviation partition; the power supply side smoothes the output of the unit by utilizing the rapid adjustment characteristic of the battery energy storage system, and restrains the charging and discharging depth by adopting a linear regression function; the load side relieves the frequency regulation pressure by utilizing the flexible scheduling characteristic of the flexible load, and depicts the constraint of the controllable output by adopting centralized control;partitioning is carried out according to different degrees of frequency deviation, and different regulation and control means are adopted in different areas to accurately respond to different states of the system. The frequency modulation performance of the system can be improved, the energy storage output condition is optimized, and the energy storage life loss is reduced.