CN115459363A - Coordination control method, device and system for offshore wind farm and energy storage system - Google Patents
Coordination control method, device and system for offshore wind farm and energy storage system Download PDFInfo
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- CN115459363A CN115459363A CN202211239011.6A CN202211239011A CN115459363A CN 115459363 A CN115459363 A CN 115459363A CN 202211239011 A CN202211239011 A CN 202211239011A CN 115459363 A CN115459363 A CN 115459363A
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J3/00—Circuit arrangements for ac mains or ac distribution networks
- H02J3/38—Arrangements for parallely feeding a single network by two or more generators, converters or transformers
- H02J3/46—Controlling of the sharing of output between the generators, converters, or transformers
- H02J3/466—Scheduling the operation of the generators, e.g. connecting or disconnecting generators to meet a given demand
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J3/00—Circuit arrangements for ac mains or ac distribution networks
- H02J3/24—Arrangements for preventing or reducing oscillations of power in networks
- H02J3/241—The oscillation concerning frequency
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J3/00—Circuit arrangements for ac mains or ac distribution networks
- H02J3/28—Arrangements for balancing of the load in a network by storage of energy
- H02J3/32—Arrangements for balancing of the load in a network by storage of energy using batteries with converting means
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J2203/00—Indexing scheme relating to details of circuit arrangements for AC mains or AC distribution networks
- H02J2203/20—Simulating, e g planning, reliability check, modelling or computer assisted design [CAD]
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J2300/00—Systems for supplying or distributing electric power characterised by decentralized, dispersed, or local generation
- H02J2300/20—The dispersed energy generation being of renewable origin
- H02J2300/28—The renewable source being wind energy
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E10/00—Energy generation through renewable energy sources
- Y02E10/70—Wind energy
- Y02E10/76—Power conversion electric or electronic aspects
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E70/00—Other energy conversion or management systems reducing GHG emissions
- Y02E70/30—Systems combining energy storage with energy generation of non-fossil origin
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Abstract
The invention discloses a coordination control method, a device and a system for an offshore wind farm and an energy storage system, wherein the method comprises the following steps: judging the operation mode of the offshore wind farm according to the first data acquired by the data acquisition and monitoring system; when the operation mode of the offshore wind farm is off-grid operation, detecting the voltage variation and the frequency variation of a receiving-end power grid; and calculating and adjusting the output power of the energy storage system by adopting a self-adaptive fuzzy reasoning system according to the voltage variation and the frequency variation. By adopting the embodiment of the invention, the voltage variation and the frequency variation of the receiving-end power grid can be detected under the condition of offline, the operation condition of the receiving-end power grid is considered, the output power of the energy storage system is adjusted by combining the self-adaptive fuzzy reasoning system with better robustness, and the adverse effect of the offline of the offshore wind farm on the receiving-end power grid is reduced.
Description
Technical Field
The invention relates to the technical field of new energy power generation load frequency control, in particular to a coordination control method, device and system for an offshore wind farm and an energy storage system.
Background
Environmental issues and the reduction of fossil fuel reserves are shifting the current energy systems to sustainable development, and in recent years, various power generation technologies based on renewable energy have been rapidly developed. Among them, the wind power generation technology is widely studied and applied as a renewable energy source due to its many advantages. Particularly, coastal economically developed areas have a large amount of power load, but the areas are usually lack of coal resources and precious land resources; in addition, the environmental requirements are high due to the dense population, so that the development of offshore wind power generation is an efficient new energy power generation method in the regions. However, due to the disadvantages of weak absorption capacity of the power grid, long distance from the main land, complex offshore wind resources and environmental conditions, the operation and maintenance of offshore wind power generation systems face serious challenges. In order to solve the problem, the prior art adopts an offshore wind turbine constant power control method based on a wind power predictor, and the method fully considers the operation constraints such as the charge state, the charge and discharge rate, the service life and the like so as to inhibit the strong fluctuation of wind power generation; in addition, the method for controlling the constant power of the offshore wind turbine is improved based on the state of charge and the time constant of the variable filter; however, most of the prior art does not consider the coordination control mechanism of offshore wind power and a battery energy storage system from the perspective of stable operation of a receiving-end power grid, especially improves the self income of an offshore wind farm during typhoon, but also needs to consider the unstable influence of sudden grid disconnection on the voltage frequency of the receiving end.
Disclosure of Invention
The invention provides a coordination control method, a device and a system for an offshore wind farm and an energy storage system, and aims to solve the technical problem that the prior art does not consider the operation condition of a receiving-end power grid and is difficult to eliminate the unstable influence of sudden grid disconnection on the receiving-end power grid.
In order to solve the above technical problem, an embodiment of the present invention provides a coordination control method for an offshore wind farm and an energy storage system, including:
judging the operation mode of the offshore wind farm according to the first data acquired by the data acquisition and monitoring system;
when the operation mode of the offshore wind farm is off-grid operation, detecting the voltage variation and the frequency variation of a receiving-end power grid;
and calculating and adjusting the output power of the energy storage system by adopting a self-adaptive fuzzy reasoning system according to the voltage variation and the frequency variation.
The method comprises the steps of judging the operation mode of the offshore wind farm, determining whether the offshore wind farm is disconnected, detecting the voltage variation and the frequency variation of the receiving-end power grid under the condition of disconnection, considering the operation condition of the receiving-end power grid, and regulating the output power of the energy storage system by combining the self-adaptive fuzzy reasoning system with better robustness, so that the adverse effect of the disconnection of the offshore wind farm on the receiving-end power grid is reduced.
Further, the calculating and adjusting the output power of the energy storage system by using an adaptive fuzzy inference system according to the voltage variation and the frequency variation specifically comprises:
fuzzifying the voltage variation and the frequency variation to obtain a first fuzzy variable corresponding to the voltage variation and a second fuzzy variable corresponding to the frequency variation;
calculating to obtain an adjustment fuzzy quantity of the output power of the energy storage system according to the first fuzzy variable, the second fuzzy variable and a fuzzy rule;
and performing defuzzification processing on the adjusted fuzzy quantity to generate a PWM control signal, and adjusting the output power of the energy storage system according to the PWM control signal.
Further, the step of calculating an adjustment fuzzy quantity of the output power of the energy storage system according to the first fuzzy variable, the second fuzzy variable and a fuzzy rule specifically includes:
and calculating to obtain the adjusting fuzzy quantity of the output power of the energy storage system by adopting a triangular membership function according to the first fuzzy variable and the second fuzzy variable.
The method detects the voltage variation and the frequency variation of the receiving-end power grid according to the fuzzy rule, calculates through the inference rule in the self-adaptive fuzzy inference system, generates the PWM control signal to adjust the energy storage system, calculates through the membership function in the self-adaptive fuzzy inference system with higher robustness while considering the running condition of the receiving-end power grid, obtains the accurate PWM control signal after defuzzification processing, adjusts the output power of the energy storage system, and reduces the adverse effect of offshore wind power station off-line on the receiving-end power grid.
Further, the fuzzy rule is adjusted by an adaptive rule, and the adaptive rule is as follows:
V＝αΔf+(1-α)ΔU,α∈(0,1)；
wherein, Δ U is a voltage variation, Δ f is a frequency variation, and α is a self-adaptive adjustment factor.
Further, the defuzzifying the adjusted fuzzy quantity to generate a PWM control signal, and adjusting the output power of the energy storage system according to the PWM control signal, specifically:
carrying out defuzzification processing on the adjusted fuzzy quantity, and converting the adjusted fuzzy quantity into a continuous quantity;
generating the PWM control signal according to the continuous quantity;
and controlling an inverter of the energy storage system according to the PWM control signal to regulate the output power of the energy storage system.
The self-adaptive fuzzy control method establishes the self-adaptive rule through the self-adaptive adjustment factor, adjusts the fuzzy rule by using the self-adaptive rule to improve the performance of the controller of the self-adaptive fuzzy system, further obtains the adjustment fuzzy quantity through the fuzzy rule, and generates the PWM control signal according to the adjustment fuzzy quantity to enable the energy storage system to utilize wind energy to generate electricity to the maximum extent, thereby reducing the adverse effect of the off-grid of the offshore wind farm on the receiving end power grid.
Further, after the operation mode of the offshore wind farm is judged according to the first data collected by the data collecting and monitoring system, the method comprises the following steps:
when the operation mode of the offshore wind farm is grid-connected operation, the energy storage system is controlled to work in a current control mode, and the energy storage system is controlled to be charged or discharged according to the operation conditions and the scheduling instruction.
According to the invention, under grid-connected operation, the energy storage system is charged and discharged according to the operation condition and the scheduling instruction, so that the energy storage system can fully utilize wind energy to generate power under off-grid operation, and the adverse effect of off-grid of the offshore sub-power plant on a receiving-end power grid is favorably reduced.
Further, the energy storage system is controlled to charge or discharge according to the operating condition and the scheduling instruction, specifically:
wherein the operating condition comprises a power limiting condition;
when the energy storage system is under the power limiting condition, controlling the energy storage system to charge or discharge according to the variable relation between the scheduling instruction and the output power; wherein, the variable relation of the output power is as follows:
P exp ＝P owp +P BESS -P LL ≤P dis-set ；
wherein, P exp For co-ordinated control of the output power, P, of the system owp For output power measurement and P of offshore wind farm BESS Is a measure of the output power of the energy storage system, P LL For total local load, P dis-set Is a scheduling set point of limited power.
The invention can further divide the operation condition into the power limiting condition, and the charging and discharging process of the energy storage system is adjusted according to the variable relation of the output power under the condition so as to ensure that the energy storage system stably works.
Further, the energy storage system is controlled to charge or discharge according to the operating condition and the scheduling instruction, specifically:
wherein the operating condition comprises a non-power limiting condition;
judging whether typhoon alarm information exists or not under the non-power limiting condition;
when no typhoon alarm information exists, controlling the energy storage system to discharge at a first preset power until the state of charge reaches a first preset value;
and when typhoon alarm information exists, controlling the energy storage system to charge at a second preset power until the state of charge reaches a second preset value.
The method further divides the operation condition into non-power limiting conditions, makes full use of typhoon alarm information under the condition, and enables the energy storage system to be charged under the condition that the offshore wind farm captures wind energy when no typhoon alarm information exists, so that electric energy is provided for the receiving-end power grid when the wind farm is disconnected, and the adverse effect of the offshore sub-power plant disconnection on the receiving-end power grid is reduced.
On the other hand, the embodiment of the invention also provides a coordination control device for the offshore wind farm and the energy storage system, which comprises: the device comprises a mode judging module, a data detecting module and a first adjusting module;
the mode judging module is used for judging the operation mode of the offshore wind farm according to first data acquired by the data acquisition and monitoring system;
the data detection module is used for detecting the voltage variation and the frequency variation of a receiving end power grid when the operation mode of the offshore wind farm is off-grid operation;
the first adjusting module is used for calculating and adjusting the output power of the energy storage system by adopting a self-adaptive fuzzy reasoning system according to the voltage variable quantity and the frequency variable quantity.
On the other hand, the embodiment of the invention also provides a coordination control system of the offshore wind farm and the energy storage system, which comprises the following components: the system comprises a data acquisition and monitoring system, a fan control system and an intelligent coordination controller;
the data acquisition and monitoring system is used for acquiring and monitoring the electrical data of the offshore wind farm and the energy storage system; the intelligent coordination controller is used for sending a scheduling instruction to the fan control system and the intelligent coordination controller;
the fan control system is used for receiving the electric information uploaded by the wind power plant and sending a scheduling instruction to the wind power plant;
the intelligent coordination controller is used for executing the coordination control method of the offshore wind farm and the energy storage system in the embodiment of the invention.
The method comprises the steps of judging the operation mode of the offshore wind farm, determining whether the offshore wind farm is disconnected, detecting the voltage variation and the frequency variation of the receiving-end power grid under the condition of disconnection, considering the operation condition of the receiving-end power grid, and regulating the output power of the energy storage system by combining the self-adaptive fuzzy reasoning system with better robustness, so that the adverse effect of the offshore wind farm disconnection on the receiving-end power grid is reduced.
Drawings
Fig. 1 is a schematic flow chart of an embodiment of a coordination control method for an offshore wind farm and an energy storage system according to the present invention;
fig. 2 is a schematic flow chart of another embodiment of a coordinated control method for an offshore wind farm and an energy storage system according to the present invention;
FIG. 3 is a coordinated control diagram of an offshore wind farm and an energy storage system in an off-grid mode of operation according to the present invention;
FIG. 4 is a diagram illustrating the calculation results of the triangular membership function of voltage deviation according to the present invention;
FIG. 5 is a diagram illustrating the calculation results of the triangular membership function of frequency deviation according to the present invention;
fig. 6 is a schematic flow chart of a coordination control method for an offshore wind farm and an energy storage system according to still another embodiment of the present invention;
FIG. 7 is a coordination control diagram of an offshore wind farm and an energy storage system in a grid-connected operation mode according to the present invention;
fig. 8 is a schematic structural diagram of an embodiment of a coordination control device for an offshore wind farm and an energy storage system according to the present invention;
FIG. 9 is a schematic structural diagram of an embodiment of a coordinated control system of an offshore wind farm and an energy storage system according to the present invention;
fig. 10 is a schematic diagram of the receiving grid frequency in a first case provided by the present invention;
FIG. 11 is a schematic diagram of the FM output power for a first case provided by the present invention;
fig. 12 is a schematic diagram of the receiving grid frequency in a second case provided by the present invention;
FIG. 13 is a schematic diagram of the FM output power for a second aspect of the present invention;
FIG. 14 is a schematic diagram of an offshore wind power output curve under a typhoon condition provided by the present invention;
fig. 15 is a schematic view of the stabilizing effect of the offshore wind farm and the battery energy storage system provided by the invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Example one
Referring to fig. 1, a flow chart of an embodiment of a coordination control method for an offshore wind farm and an energy storage system according to the present invention mainly includes steps 101 to 103, which are as follows:
step 101: and judging the operation mode of the offshore wind farm according to the first data acquired by the data acquisition and monitoring system.
In this embodiment, the SCADA (supervisory control and data acquisition) system is configured to collect and monitor electrical information uploaded by the wind turbine control system and the intelligent coordination controller, and send a scheduling instruction to the wind turbine control system and the coordination controller, so that the wind turbine control system and the coordination controller control grid connection or grid disconnection of the offshore wind farm and control charging or discharging of the energy storage system. Further, the operation modes include: off-grid operation and grid-connected operation; under the conditions that the operation environment of an offshore wind farm is severe, particularly the safety of a fan is seriously influenced by typhoon weather, the offshore wind farm is disconnected from a power grid, namely, the offshore wind farm is operated off the grid, and the fan stops generating power in the mode, so that a yaw motor loses the working power and the direction of blades cannot be changed; therefore, it is necessary to provide emergency power to the fan yaw motor and other auxiliary systems during off-grid operation to minimize the impact of typhoons on the wind turbine.
Step 102: and when the operation mode of the offshore wind farm is off-grid operation, detecting the voltage variation and the frequency variation of the receiving-end power grid.
In this embodiment, during off-grid operation, a Constant Voltage and Constant Frequency (CVCF) control is applied to the energy storage system, while maintaining the active power balance of the receiving-end grid, where the expression of the active power balance is as follows:
P BESS +P owp -P LL ＝P DE -P Load ；
wherein, P BESS Is a measure of the output power of the energy storage system, P owp Is an output power measurement, P, of an offshore wind farm LL For total local load, P DE For co-ordinated control of the output power, P, of the system Load Is the consumed power of the load. Furthermore, P LL ＝P Lc +P Lp +P Ly +P Lo Wherein P is Lc Fan monitoring system load power consumption, P Lp Consuming power for the load of a fan pitch system, P Ly Consuming power for a fan yaw system load, P Lo Consuming power for other loads.
Step 103: and calculating and adjusting the output power of the energy storage system by adopting a self-adaptive fuzzy reasoning system according to the voltage variation and the frequency variation.
In this embodiment, there are two input variables of the adaptive fuzzy inference system, which are respectively a voltage variation and a frequency variation, and after calculation and deblurring processing are performed through an inference rule, an intermediate quantity is obtained, for example: adjusting the amount of blur; the adjustment blur amount may be used to generate a PWM signal to control an inverter of the energy storage system.
In this embodiment, the Energy Storage System may adopt a Battery Energy Storage System (BESS), BESS is one of effective means for smoothing renewable resource intermittent power generation, load peak regulation, frequency regulation, and the like, and a Power Conversion System (PCS) of BESS may operate in a Voltage Control Mode (VCM) and a Current Control Mode (CCM); during grid-connected operation, the PCS works in a CCM mode, and during off-grid operation, the PCS works in a VCM. Unlike offshore wind power, the power control of BESS can work in four quadrants, which means that it can generate and absorb both active and reactive power, while the converter of offshore wind power cannot absorb active power. In addition, under the condition of off-grid operation, the traditional mode is to use a diesel generator as an emergency standby power supply, but the center pressure of typhoon is very low, the diesel generator cannot be normally started or operated, and the BESS can overcome the defect and be used as a standby power supply to protect the wind turbine from safety accidents. Furthermore, BESS may also serve as a grid forming unit for local loads, ensuring power balance between power generation and the load in Voltage Control Mode (VCM).
In this embodiment, the output power includes: active power and reactive power.
Referring to fig. 2, a schematic flow chart of another embodiment of the coordination control method for the offshore wind farm and the energy storage system according to the present invention mainly includes steps 201 to 203, which are as follows:
in this embodiment, step 103 specifically includes step 201 to step 203.
Step 201: and performing fuzzification processing on the voltage variation and the frequency variation to obtain a first fuzzy variable corresponding to the voltage variation and a second fuzzy variable corresponding to the frequency variation.
Referring to fig. 3, a coordination control diagram of an offshore wind farm and an energy storage system in an off-grid operation mode is shown, in which a voltage variation and a frequency variation are first subjected to a fuzzy processing, so that a fuzzy device can extract effective information by using a membership function; the extracted information includes a first fuzzy variable and a second fuzzy variable.
Step 202: and calculating to obtain the adjusting fuzzy quantity of the output power of the energy storage system according to the first fuzzy variable, the second fuzzy variable and a fuzzy rule.
In this embodiment, the calculating, according to the first fuzzy variable, the second fuzzy variable and the fuzzy rule, to obtain the adjusted fuzzy quantity of the output power of the energy storage system includes: and calculating the adjusting fuzzy quantity of the output power of the energy storage system by adopting a triangular membership function according to the first fuzzy variable and the second fuzzy variable.
The method detects the voltage variation and the frequency variation of the receiving-end power grid according to the fuzzy rule, calculates through the inference rule in the self-adaptive fuzzy inference system, generates the PWM control signal to adjust the energy storage system, calculates through the membership function in the self-adaptive fuzzy inference system with higher robustness while considering the running condition of the receiving-end power grid, obtains the accurate PWM control signal after defuzzification processing, adjusts the output power of the energy storage system, and reduces the adverse effect of offshore wind power plant grid disconnection on the receiving-end power grid.
Referring to fig. 4 and 5, schematic diagrams of the calculation results of the triangular membership functions of the voltage deviation and the frequency deviation, respectively, where NB represents negative large, NM represents negative medium, NS represents negative small, Z represents zero, PS represents positive small, PM represents positive medium, and PB represents positive large; in addition, each membership function defines its own weight and gives linguistic variables, which are substituted into the fuzzy inference system and calculate the inference result according to the fuzzy rule in the fuzzy inference system, for example: according to the voltage error NB and the error rate NB, a fuzzy output NB can be calculated according to a fuzzy rule.
In this embodiment, the fuzzy rule is adjusted by an adaptive rule, where the adaptive rule is:
V＝αΔf+(1-α)ΔU,α∈(0,1)；
wherein, Δ U is a voltage variation, Δ f is a frequency variation, and α is a self-adaptive adjustment factor.
Step 203: and carrying out defuzzification processing on the adjusted fuzzy quantity to generate a PWM control signal, and adjusting the output power of the energy storage system according to the PWM control signal.
In this embodiment, the defuzzifying the adjusted fuzzy quantity to generate a PWM control signal, and adjusting the output power of the energy storage system according to the PWM control signal specifically includes: carrying out defuzzification processing on the adjusted fuzzy quantity, and converting the adjusted fuzzy quantity into a continuous quantity; generating the PWM control signal according to the continuous quantity; and controlling a converter of the energy storage system according to the PWM control signal to regulate the output power of the energy storage system.
In this embodiment, the non-fuzzy output is obtained by performing defuzzification processing on the adjustment fuzzy quantity; the non-ambiguous output is usable to generate a PWM control signal.
The self-adaptive fuzzy control method establishes the self-adaptive rule through the self-adaptive adjustment factor, adjusts the fuzzy rule by using the self-adaptive rule to improve the performance of the controller of the self-adaptive fuzzy system, further obtains the adjustment fuzzy quantity through the fuzzy rule, and generates the PWM control signal according to the adjustment fuzzy quantity to enable the energy storage system to utilize wind energy to generate electricity to the maximum extent, thereby reducing the adverse effect of the off-grid of the offshore wind farm on the receiving end power grid.
Referring to fig. 6, a schematic flow chart of another embodiment of the coordination control method for an offshore wind farm and an energy storage system according to the present invention mainly includes step 301, which is as follows:
in this embodiment, after step 101 is executed, step 301 may also be executed.
Step 301: when the operation mode of the offshore wind farm is grid-connected operation, the energy storage system is controlled to work in a current control mode, and the energy storage system is controlled to be charged or discharged according to the operation conditions and the scheduling instruction.
In this embodiment, the controlling the energy storage system to charge or discharge according to the operating condition and the scheduling instruction specifically includes:
wherein the operating condition comprises a power limit condition; when the energy storage system is under the power limiting condition, controlling the energy storage system to charge or discharge according to the variable relation between the scheduling instruction and the output power; wherein, the variable relation of the output power is as follows:
P exp ＝P owp +P BESS -P LL ≤P dis-set ；
wherein, P exp For co-ordinated control of the output power of the system, P owp For output power measurement and P of offshore wind farm BESS Is a measure of the output power of the energy storage system, P LL For total local load, P dis-set Is a scheduling set point of limited power.
The invention can further divide the operation condition into the power limiting condition, and the charging and discharging process of the energy storage system is adjusted according to the variable relation of the output power under the condition so as to ensure that the energy storage system stably works.
In this embodiment, the controlling the energy storage system to charge or discharge according to the operating condition and the scheduling instruction specifically includes: wherein the operating condition comprises a non-power limiting condition; judging whether typhoon alarm information exists or not when the typhoon alarm information is in a non-power limiting condition; when no typhoon alarm information exists, controlling the energy storage system to discharge at a first preset power until the state of charge reaches a first preset value; and when typhoon alarm information exists, controlling the energy storage system to charge at a second preset power until the state of charge reaches a second preset value.
The method further divides the operation condition into a non-power limiting condition, makes full use of typhoon alarm information under the condition, and enables the energy storage system to be charged under the condition that the offshore wind farm captures wind energy when no typhoon alarm information exists, so that electric energy is provided for a receiving-end power grid when the wind farm is disconnected, and the adverse effect of the offshore sub-power plant disconnection on the receiving-end power grid is reduced.
In this embodiment, the state of charge is:
wherein SOC (t) is the state of charge of the energy storage system at time t, P (t) is the output power of the energy storage system, eta c For charging efficiency, η d For discharge efficiency, E is the rated capacity of the energy storage system. When the energy storage system is discharged, P (t) is positive and when charged, it is negative.
In this embodiment, in order to avoid overcharging or deep discharging and to maintain the necessary reserve capacity of the energy storage system, special attention should be paid to regulating the SOC within an appropriate operating range; the entire SOC range may be divided into five sub-ranges from 0 to 1, where SOC max The maximum operating limit or first preset value of the SOC is usually set to be slightly less than the maximum allowable SOC of the energy storage system to avoid overcharging, and the SOC is min The minimum operating limit or second preset value of the SOC is typically set to be slightly greater than the minimum SOC allowed by the energy storage system to avoid deep discharge. Under the conditions of grid-connected operation and off-grid operation, the SOC of the energy storage system is allowed to be within a specified range ref In an emergency, the SOC is allowed to be within an emergency range. SOC ref The reference SOC is stable and economical in operation in a grid-connected mode. SOC cannot be greater than SOC in any case max Or less than SOC min To prevent damage to the energy storage system due to overcharging or deep discharging.
According to the invention, under grid-connected operation, the energy storage system is charged and discharged according to the operation condition and the scheduling instruction, so that the energy storage system can fully utilize wind energy to generate power under off-grid operation, and the adverse effect of off-grid of the offshore sub-power plant on a receiving-end power grid is favorably reduced.
Referring to fig. 7, for the coordination control diagram of the offshore wind farm and the energy storage system in the grid-connected operation mode provided by the present invention, when the offshore wind farm is in grid-connected operation, the energy storage system works in CCM, and performs charging and discharging according to the operation conditions; and the offshore wind farm works in a Maximum Power Point Tracking (MPPT) mode. WhereinIn the station coordination layer, the intelligent coordination controller receives electrical information uploaded by the offshore wind farm control system and the energy storage control system and simultaneously sends a scheduling instruction to the offshore wind farm control system and the energy storage control system so as to coordinate and control the fan and the energy storage converter; p' owp Is theoretical output power of offshore wind power, P' BESS Is the rated power, P, of the energy storage system set Net set point to limit power, P' owp-set And P' BESS-set Set-point or control variable, P, for offshore wind power and energy storage systems, respectively MPPT For the output power, P, of an offshore wind farm operating in MPPT mode ch And P dis Respectively a first preset power and a second preset power.
Fig. 8 is a schematic structural diagram of an embodiment of a coordination control device for an offshore wind farm and an energy storage system according to the present invention, which mainly includes: a mode judging module 401, a data detecting module 402 and a first adjusting module 403.
In this embodiment, the mode determining module 401 is configured to determine an operation mode of the offshore wind farm according to the first data acquired by the data acquiring and monitoring system.
In this embodiment, the coordination control device for the offshore wind farm and the energy storage system further includes: a second conditioning module; the second adjusting module is used for controlling the energy storage system to work in a current control mode when the mode judging module 401 judges that the operation mode of the offshore wind farm is grid-connected operation, and controlling the energy storage system to charge or discharge according to the operation condition and the scheduling instruction.
The data detection module 402 is configured to detect a voltage variation and a frequency variation of a receiving-end power grid when the operation mode of the offshore wind farm is off-grid operation.
The first adjusting module 403 is configured to calculate and adjust the output power of the energy storage system by using an adaptive fuzzy inference system according to the voltage variation and the frequency variation.
The first adjusting module 403 in this embodiment includes: the fuzzy processing unit, the calculating unit and the adjusting unit; the fuzzification processing unit is used for fuzzifying the voltage change quantity and the frequency change quantity to obtain a first fuzzy variable corresponding to the voltage change quantity and a second fuzzy variable corresponding to the frequency change quantity; the calculation unit is used for calculating and obtaining the adjustment fuzzy quantity of the output power of the energy storage system according to the first fuzzy variable, the second fuzzy variable and the fuzzy rule; the adjusting unit is used for performing defuzzification processing on the adjusting fuzzy quantity to generate a PWM control signal, and adjusting the output power of the energy storage system according to the PWM control signal.
Fig. 9 is a schematic structural diagram of an embodiment of a coordinated control system of an offshore wind farm and an energy storage system provided in the present invention, including: the system comprises a data acquisition and monitoring system, a fan control system and an intelligent coordination controller.
In this embodiment, the data collecting and monitoring system is used for collecting and monitoring the electrical data of the offshore wind farm and the energy storage system; and the intelligent coordination controller is used for sending a scheduling instruction to the fan control system and the intelligent coordination controller.
And the fan control system is used for receiving the electric information uploaded by the wind power plant and sending a scheduling instruction to the wind power plant.
The intelligent coordination controller is used for executing the coordination control method of the offshore wind farm and the energy storage system.
In the embodiment, the wind turbine control system controls and adjusts the operation state of the wind power plant through a scheduling instruction, the wind power plant supplies power for a local load on one hand, and supplies electric energy to a receiving-end power grid after passing through a power generation-side converter and a grid-connected-side converter on the other hand; the energy storage system supplies electric energy to a receiving-end power grid through a grid-connected side converter while being controlled by the intelligent coordination controller.
In this embodiment, the local loads include a monitoring system, a yaw system, a pitch system, and other loads; in addition, the electric energy generated by the coordinated control system is obtained by converting wind energy from an offshore wind farm, the wind wheel blades of the wind turbine capture energy from wind and convert the energy into rotational kinetic energy, then the mechanical energy is transmitted to the generator through a mechanical transmission system, and is converted into magnetic field energy and finally into electric energy through the generator. According to the Betz law, the maximum power that a wind rotor can extract from the wind can be expressed as:
wherein, P m Is the maximum mechanical power of the wind wheel, ρ is the air density, R is the radius of the fan blades, v is the wind speed, C p = f (λ, α) is the power coefficient of the fan, λ = ω m R/v is tip speed ratio, ω m Is the mechanical angular velocity of the wind rotor and alpha is the pitch angle. According to the Betz limit, i.e. the theoretical limit of the power that the fan can extract from the air flow, C p Is 16/27 ≈ 0.593. The actual value is small in consideration of the air swirl loss.
In addition, the output power of the wind turbine is a nonlinear function of the wind speed, and is mainly determined by the actual wind speed at the hub of the wind turbine and the output power characteristic of the wind turbine. Such as the operating efficiency of the generator, rotor, gearbox and inverter. The output power characteristic of a pitch fan may be determined by several parameters, such as v ci 、v cr And v co Cut-in, steady-state and cut-out wind speeds, P, respectively r Is the rated output power. The output power of a general purpose wind turbine is most often described by a simplified linear equation:
wherein, P e (v) For the output power of the fan with respect to the wind speed v, P for a variable pitch fan x ＝P r For fixed pitch wind turbines, P x Can be expressed as:
wherein, P co Is v = v co The embodiment of the invention adopts the model to calculate the theoretical output power of the time-varying fan.
Example two
In order to verify the effectiveness of the method, the actual offshore wind farm in Guangdong is used as a simulation object in the embodiment, and the control effect of the method in the grid-connected mode and the off-connected mode is tested in Matlab through simulation. The direct-drive fan adopted by the wind power plant has the rated capacity of 10MW and the BESS capacity of 6MW. Relevant parameters of BESS in the offshore wind power and battery energy storage coordinated control system can be seen in the following table:
referring to fig. 10 and fig. 11, schematic diagrams of receiving-end grid frequency and frequency-modulated output power under a first condition provided by the present invention are shown, respectively, where in this embodiment, 10s of an operation process of a wind power generation system is simulated under a grid-connected operation condition, and an SOC of a BESS is 0.50 at time 0 s. There are several prerequisites for operation and control in grid-tie mode: 1) P exp ≤P dis-set ；2)SOC low ≤SOC；3)SOC≤SOC high . The time when the wind speed is higher before the typhoon comes, the offshore wind power system is usually operated in the MPPT mode under the condition, however, in order to realize friendly access, the offshore wind farm usually needs to provide certain frequency modulation capability, and the BESS is a key factor participating in the frequency modulation, so the part of simulation is divided into two cases: firstly, when the frequency of the power grid is 2s, the frequency is increased from normal 50Hz to 51Hz; secondly, when the frequency of the power grid is 2s, the frequency is reduced from normal 50Hz to 48Hz. In order to reflect the effect of the proposed adaptive control strategy, a constant frequency modulation power control strategy without BESS is adopted to compare with the proposed adaptive control strategy.
Referring to fig. 12 and fig. 13, schematic diagrams of the receiving-end grid frequency and the frequency-modulated output power under the second condition provided by the present invention are shown, respectively, wherein when the frequency-modulated power adaptive controller detects that the grid frequency rises within 2s, the wind farm grid-connected power needs to be reduced, so the BESS should absorb part of the energy. In addition, different frequency modulation output powers can be obtained by adopting different control algorithms, the two control algorithms are respectively applied to the wind field with the same energy storage health state, and when the wind field BESS adopts a frequency modulation power self-adaptive control strategy, the power of absorbing energy is about 5.5kW. When the wind field BESS adopts a constant frequency modulation power control strategy, the power of absorbed energy is 5kW. Therefore, in the healthy state of energy storage, the offshore wind farm BESS can absorb more energy when adopting a frequency modulation power self-adaptive control strategy, so that more output is provided for the frequency modulation of the power grid, and the stability of the frequency of the power grid is further improved.
In this embodiment, when the fm power adaptive controller detects that the grid frequency is decreasing in 2s, the grid-connected power of the wind farm needs to be increased, so each set of BESS should release part of the energy. As shown in fig. 6, different control algorithms are used to obtain different frequency modulation output powers, the two control algorithms are respectively applied to the wind farm BESS in the same energy storage health state, when the wind farm BESS adopts a frequency modulation power adaptive control strategy, the power of the released energy is about 5.5kW, and when the wind farm BESS adopts a constant frequency modulation power control strategy, the power of the released energy is about 5kW. Therefore, in the energy storage healthy state, the HESS can release more energy when a frequency modulation power self-adaptive control strategy is adopted, so that support is provided for the frequency stability of the power grid, and the frequency stability of the power grid is further improved.
Fig. 14 is a schematic diagram of an offshore wind power output curve under a typhoon condition according to the present invention. In grid disconnect mode, the offshore wind farm is gradually shut down, and the isolation system consists of the BESS and the local load. According to a detailed analysis of the local loads, the maximum power of the yaw motor is 71.5kW, the rated power is 5.5kW, and the maximum power of other loads is about 20kW. These local loads vary with the load of the wind turbine, which is related to wind speed, yaw angle, etc. From FIG. 14, it can be seen that the cut-off wind speed is 20m/s and the offshore wind power drops from the rated value to zero within 25 minutes. This demonstrates how the steady offshore wind power output on a small time scale is extremely reduced causing power imbalance problems.
Fig. 15 is a schematic diagram of stabilizing effects of the offshore wind farm and the battery energy storage system provided by the invention, wherein the stabilizing effect of the energy storage system on wind power fluctuation is obvious. During typhoon passing, the energy storage system can be charged in advance and quickly discharged when power shortage occurs; wherein, in fig. 15, power is positive indicating discharge; and further, the power stabilizing control of the coordinated control system is realized, so that the overall power output of the system is closer to a given value, and the adverse effect of the overall power output on the stable operation of the power grid is reduced. In the process of energy storage and output, the power and the energy of the energy storage and output device are both operated in a safe range.
The method comprises the steps of judging the operation mode of the offshore wind farm, determining whether the offshore wind farm is disconnected, detecting the voltage variation and the frequency variation of the receiving-end power grid under the condition of disconnection, considering the operation condition of the receiving-end power grid, and regulating the output power of the energy storage system by combining the self-adaptive fuzzy reasoning system with better robustness, so that the adverse effect of the disconnection of the offshore wind farm on the receiving-end power grid is reduced.
The above-mentioned embodiments are provided to further explain the objects, technical solutions and advantages of the present invention in detail, and it should be understood that the above-mentioned embodiments are only examples of the present invention and are not intended to limit the scope of the present invention. It should be understood that any modifications, equivalents, improvements and the like, which come within the spirit and principle of the invention, may occur to those skilled in the art and are intended to be included within the scope of the invention.
Claims (10)
1. A coordination control method for an offshore wind farm and an energy storage system is characterized by comprising the following steps:
judging the operation mode of the offshore wind farm according to the first data acquired by the data acquisition and monitoring system;
when the operation mode of the offshore wind farm is off-grid operation, detecting the voltage variation and the frequency variation of a receiving-end power grid;
and calculating and adjusting the output power of the energy storage system by adopting a self-adaptive fuzzy reasoning system according to the voltage variation and the frequency variation.
2. The method according to claim 1, wherein the calculating and adjusting the output power of the energy storage system by using an adaptive fuzzy inference system according to the voltage variation and the frequency variation comprises:
fuzzifying the voltage variation and the frequency variation to obtain a first fuzzy variable corresponding to the voltage variation and a second fuzzy variable corresponding to the frequency variation;
calculating to obtain an adjustment fuzzy quantity of the output power of the energy storage system according to the first fuzzy variable, the second fuzzy variable and a fuzzy rule;
and performing defuzzification processing on the adjusted fuzzy quantity to generate a PWM control signal, and adjusting the output power of the energy storage system according to the PWM control signal.
3. The method according to claim 2, wherein the adjusting fuzzy amount of the output power of the energy storage system is calculated according to the first fuzzy variable, the second fuzzy variable and a fuzzy rule, and specifically comprises:
and calculating the adjusting fuzzy quantity of the output power of the energy storage system by adopting a triangular membership function according to the first fuzzy variable and the second fuzzy variable.
4. The method according to claim 2, wherein the fuzzy rule is adjusted by an adaptive rule, and the adaptive rule is:
V＝αΔf+(1-α)ΔU,α∈(0,1)；
wherein, Δ U is a voltage variation, Δ f is a frequency variation, and α is a self-adaptive adjustment factor.
5. The method according to claim 2, wherein the step of defuzzifying the adjustment fuzzy quantity to generate a PWM control signal and adjusting the output power of the energy storage system according to the PWM control signal comprises:
carrying out defuzzification processing on the adjusted fuzzy quantity, and converting the adjusted fuzzy quantity into a continuous quantity;
generating the PWM control signal according to the continuous quantity;
and controlling an inverter of the energy storage system according to the PWM control signal to regulate the output power of the energy storage system.
6. The method for coordinating and controlling the offshore wind farm and the energy storage system according to any one of claims 1 to 5, wherein after the determining the operation mode of the offshore wind farm according to the first data collected by the data collecting and monitoring system, the method comprises:
and when the operation mode of the offshore wind farm is grid-connected operation, controlling the energy storage system to work in a current control mode, and controlling the energy storage system to charge or discharge according to the operation condition and the scheduling instruction.
7. The coordination control method for the offshore wind farm and the energy storage system according to claim 6, wherein the energy storage system is controlled to be charged or discharged according to the operating conditions and the scheduling instructions, specifically:
wherein the operating condition comprises a power limiting condition;
when the energy storage system is under the power limiting condition, controlling the energy storage system to charge or discharge according to the variable relation between the scheduling instruction and the output power; wherein the output power variable relation is as follows:
P exp ＝P owp +P BESS -P LL ≤P dis-set ；
wherein, P exp For co-ordinated control of the output power of the system, P owp Output power measurement and P for offshore wind farms BESS Is a measure of the output power of the energy storage system, P LL For total local load, P dis-set Scheduling settings for limited powerAnd (4) point.
8. The coordination control method for the offshore wind farm and the energy storage system according to claim 6, wherein the coordination control method controls the energy storage system to charge or discharge according to the operating condition and the scheduling instruction, and specifically comprises the following steps:
wherein the operating condition comprises a non-power limiting condition;
judging whether typhoon alarm information exists or not under the non-power limiting condition;
when no typhoon alarm information exists, controlling the energy storage system to discharge at a first preset power until the state of charge reaches a first preset value;
and when typhoon alarm information exists, controlling the energy storage system to charge at a second preset power until the state of charge reaches a second preset value.
9. A coordination control device of an offshore wind farm and an energy storage system is characterized by comprising: the device comprises a mode judgment module, a data detection module and a first regulation module;
the mode judging module is used for judging the operation mode of the offshore wind farm according to first data acquired by the data acquisition and monitoring system;
the data detection module is used for detecting the voltage variation and the frequency variation of a receiving end power grid when the operation mode of the offshore wind farm is off-grid operation;
and the first adjusting module is used for calculating and adjusting the output power of the energy storage system by adopting a self-adaptive fuzzy reasoning system according to the voltage variable quantity and the frequency variable quantity.
10. A coordinated control system of an offshore wind farm and an energy storage system, comprising: the system comprises a data acquisition and monitoring system, a fan control system and an intelligent coordination controller;
the data acquisition and monitoring system is used for acquiring and monitoring the electrical data of the offshore wind farm and the energy storage system; the intelligent coordination controller is used for sending a scheduling instruction to the fan control system and the intelligent coordination controller;
the fan control system is used for receiving the electric information uploaded by the wind power plant and sending a scheduling instruction to the wind power plant;
the intelligent coordination controller is used for executing the coordination control method of the offshore wind farm and the energy storage system according to any one of claims 1 to 8.
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN116632880A (en) * | 2023-07-25 | 2023-08-22 | 深圳量云能源网络科技有限公司 | Multifunctional coordination control method and device for wind farm energy storage system and terminal equipment |
| CN117154823A (en) * | 2023-09-04 | 2023-12-01 | 南方电网科学研究院有限责任公司 | Energy storage-based stability improving method and related equipment for direct-drive permanent magnet fan |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116632880A (en) * | 2023-07-25 | 2023-08-22 | 深圳量云能源网络科技有限公司 | Multifunctional coordination control method and device for wind farm energy storage system and terminal equipment |
| CN116632880B (en) * | 2023-07-25 | 2024-04-30 | 深圳量云能源网络科技有限公司 | Multifunctional coordination control method and device for wind farm energy storage system and terminal equipment |
| CN117154823A (en) * | 2023-09-04 | 2023-12-01 | 南方电网科学研究院有限责任公司 | Energy storage-based stability improving method and related equipment for direct-drive permanent magnet fan |
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