A method and system for coordinated control of primary frequency regulation based on sectionalized adjustment

Abstract

The application discloses a kind of primary frequency modulation cooperative control method and system based on segmented adjustment, including in response to trigger primary frequency modulation action signal, according to wind farm demand power and battery energy storage output gear, determine first battery energy storage output power;In response to the execution time length of first energy storage action reaches first response time length, and grid frequency exceeds frequency dead zone, according to integral electric quantity contribution rate and battery energy storage output gear, determine second battery energy storage output power;In response to the execution time length of second energy storage action reaches second response time length, and grid frequency exceeds frequency dead zone, according to integral electric quantity contribution rate and regulation dead zone, determine third battery energy storage output power.The application can be stabilized in reasonable range on the basis of guaranteeing that the direction of initial stage primary frequency modulation action is correct, action output meets amplitude requirement, realizes that energy storage battery participates wind farm primary frequency modulation control, and improves the control effect of wind farm primary frequency modulation.

Description

Technical Field

[0001] This invention relates to the field of primary frequency regulation control technology for wind farms, and in particular to a primary frequency regulation coordinated control method and system based on segmented adjustment. Background Technology

[0002] As the proportion of installed wind power capacity in my country gradually increases, annual power generation also steadily rises. Wind power has now become one of the main power sources for the power grid. Furthermore, with the increasing refinement of grid ancillary service management, the assessment of ancillary services provided by wind farms and other new energy power plants will be further strengthened. Primary frequency regulation, as a key ancillary service involving the dynamic balance of active power and frequency security of the power grid, directly impacts the grid connection assessment and operational revenue of wind farms. Although the assessment requirements of the "two detailed rules" vary across local power grids, primary frequency regulation ancillary service projects generally use the integral power contribution rate as the assessment criterion. A low integral power contribution rate leads to a failed assessment, while a high rate leads to a failed accuracy assessment, and a reversed rate results in a failed action direction assessment. In short, primary frequency regulation should meet the requirements of rapid action, positive output, and an integral power contribution rate within a reasonable range.

[0003] Currently, there are various technical routes available for battery cell configurations in energy storage, among which supercapacitor energy storage batteries combine the advantages of both capacitor and battery energy storage. Compared to traditional chemical batteries, supercapacitor batteries have the significant advantage of high-rate rapid charging and discharging, and their wide adjustable power range can be highly compatible with the requirements of primary frequency regulation. By configuring supercapacitor energy storage batteries in wind farms, and configuring the charging and discharging power according to the local primary frequency regulation load limit, the primary frequency regulation control effect of the wind farm can be improved by utilizing supercapacitor battery energy storage.

[0004] While supercapacitor battery energy storage boasts the advantage of a high charge / discharge power ratio, enabling rapid charging and discharging at high rates, its application in primary frequency regulation also places high demands on speed, accuracy, and stability in response to grid frequency changes. Existing control strategies for battery energy storage participating in wind farm primary frequency regulation mostly focus on the tracking effect of energy storage output on the active power demand of primary frequency regulation, or are based on joint scheduling strategies of wind turbines and energy storage. However, these existing methods cannot solve the problems of increased computational pressure on the control system caused by the principle of real-time tracking of primary frequency regulation demand by energy storage, nor the increased control difficulty of the battery itself caused by changes in energy storage output with demand. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention provides a primary frequency regulation collaborative control method and system based on segmented adjustment. This method can solve the problems of increased computational pressure on the control system caused by the principle of real-time tracking of primary frequency regulation demand by energy storage, and increased control difficulty of the battery body caused by changes in energy storage output with demand. This enables the energy storage battery to participate in the primary frequency regulation control of the wind farm.

[0006] In a first aspect, the present invention provides a primary frequency modulation coordinated control method based on segmented adjustment, the method comprising:

[0007] Determine whether to trigger a primary frequency regulation action signal based on whether the grid frequency of the wind farm exceeds the primary frequency regulation dead zone of the unit;

[0008] In response to the triggering of a frequency regulation action signal, the first battery energy storage output power is determined based on the wind farm's required power and several preset battery energy storage output levels, and the first energy storage action is executed.

[0009] In response to the execution time of the first energy storage action reaching the first response time, and the grid frequency exceeding the primary frequency regulation dead zone of the unit, the second battery energy storage output power is determined based on the integral power contribution rate of the wind farm and the battery energy storage output level, and the second energy storage action is executed.

[0010] In response to the second energy storage action reaching the second response time and the grid frequency exceeding the unit's primary frequency regulation dead zone, the third battery energy storage output power is determined based on the integral power contribution rate and the preset regulation dead zone, and the third energy storage action is executed until the grid frequency recovers to the range of the unit's primary frequency regulation dead zone.

[0011] Furthermore, the step of determining the first battery energy storage output power based on the wind farm's power demand and a preset number of battery energy storage output levels, and then executing the first energy storage action, includes:

[0012] Select a battery energy storage output level from a number of battery energy storage output levels that is adjacent to and greater than the required power of the wind farm as the first battery energy storage output level, and use the level power and level ratio corresponding to the first battery energy storage output level as the first battery energy storage output power and the first output ratio.

[0013] The first energy storage action is executed based on the first battery energy storage output power and the first output ratio.

[0014] Furthermore, the step of determining the second battery energy storage output power based on the wind farm's integral power contribution rate and the battery energy storage output level, and then executing the second energy storage action, includes:

[0015] Obtain the integral power contribution rate of the wind farm within the first frequency regulation period, and compare the integral power contribution rate with a first contribution rate threshold.

[0016] When the integral power contribution rate is greater than the first contribution rate threshold, the battery energy storage output level that is adjacent to the wind farm's demand power and less than the wind farm's demand power is taken as the second battery energy storage output level, and the level power and level multiplier corresponding to the second battery energy storage output level are taken as the second battery energy storage output power and the second output multiplier.

[0017] Based on the second battery energy storage output power and the second output rate, execute the second energy storage action until the integral energy contribution rate is less than the second contribution rate threshold.

[0018] In response to the integral energy contribution rate being less than the second contribution rate threshold, or when the integral energy contribution rate is less than or equal to the first contribution rate threshold, a first energy storage action is performed based on the first battery energy storage output power and the first output rate.

[0019] Furthermore, the step of determining the third battery energy storage output power based on the integral energy contribution rate and the preset control dead zone, and executing the third energy storage action, includes:

[0020] Determine whether the integral power contribution rate is within the preset control dead zone. If so, use the wind farm demand power as the third battery energy storage output power; otherwise, use the product of the wind farm demand power and the proportional coefficient as the third battery energy storage output power.

[0021] The third energy storage action is executed based on the third battery energy storage output power.

[0022] Furthermore, before determining whether to trigger a primary frequency regulation action signal based on whether the grid frequency of the wind farm exceeds the primary frequency regulation dead zone of the generator, the method further includes:

[0023] The grid power and grid frequency of the wind farm are collected in real time, and the wind farm's demand power and integral power contribution rate within the primary frequency regulation are calculated based on the grid power and grid frequency.

[0024] Furthermore, the first response duration is determined by the forward action time parameter;

[0025] The second response duration is determined by the positive action time parameter and the lowest effective value of the first frequency modulation action;

[0026] The first contribution rate threshold is determined by the maximum exemption value;

[0027] The second contribution rate threshold is determined by the minimum exemption value and the maximum exemption value;

[0028] The proportionality coefficient is determined by the integral power contribution rate.

[0029] Secondly, the present invention provides a primary frequency modulation coordinated control system based on segmented adjustment, the system comprising:

[0030] The signal triggering module is used to determine whether to trigger the primary frequency regulation action signal based on whether the grid frequency of the wind farm exceeds the primary frequency regulation dead zone of the unit;

[0031] The first frequency regulation control module is used to respond to the signal that triggers a primary frequency regulation action, determine the first battery energy storage output power based on the wind farm's required power and several preset battery energy storage output levels, and execute the first energy storage action.

[0032] The second frequency regulation control module is used to respond to the first energy storage action reaching the first response time and the grid frequency exceeding the primary frequency regulation dead zone of the unit, determine the second battery energy storage output power based on the wind farm's integral power contribution rate and the battery energy storage output level, and execute the second energy storage action.

[0033] The third frequency regulation control module is used to respond to the second energy storage action reaching the second response time and the grid frequency exceeding the unit's primary frequency regulation dead zone, determine the third battery energy storage output power based on the integral power contribution rate and the preset regulation dead zone, and execute the third energy storage action until the grid frequency recovers to the range of the unit's primary frequency regulation dead zone.

[0034] Furthermore, the first frequency modulation control module includes a first output power determination module and a first energy storage control module;

[0035] The first output power determination module is used to select from a plurality of battery energy storage output power levels a battery energy storage output power level that is adjacent to and greater than the wind farm's required power level as the first battery energy storage output power level, and to use the power level and the power level ratio corresponding to the first battery energy storage output power level as the first battery energy storage output power and the first output power ratio.

[0036] The first energy storage control module executes a first energy storage action based on the first battery energy storage output power and the first output ratio.

[0037] Furthermore, the second frequency modulation control module includes a second output power determination module and a second energy storage control module;

[0038] The second output power determination module is used to obtain the integral power contribution rate of the wind farm within the first frequency regulation, and compare the integral power contribution rate with the first contribution rate threshold.

[0039] When the integral power contribution rate is greater than the first contribution rate threshold, the battery energy storage output level that is adjacent to the wind farm's demand power and less than the wind farm's demand power is taken as the second battery energy storage output level, and the level power and level multiplier corresponding to the second battery energy storage output level are taken as the second battery energy storage output power and the second output multiplier.

[0040] The second energy storage control module is used to execute a second energy storage action based on the second battery energy storage output power and the second output rate, until the integral energy contribution rate is less than the second contribution rate threshold.

[0041] In response to the integral energy contribution rate being less than the second contribution rate threshold, or when the integral energy contribution rate is less than or equal to the first contribution rate threshold, a first energy storage action is performed based on the first battery energy storage output power and the first output rate.

[0042] Furthermore, the third frequency modulation control module includes a third output power determination module and a third energy storage control module;

[0043] The third output power determination module is used to determine whether the integral power contribution rate is within the preset control dead zone. If so, the wind farm demand power is used as the third battery energy storage output power; otherwise, the product of the wind farm demand power and the proportional coefficient is used as the third battery energy storage output power.

[0044] The third energy storage control module is used to execute the third energy storage action according to the energy output power of the third battery.

[0045] This invention provides a primary frequency regulation coordinated control method and system based on segmented adjustment. Using the primary frequency regulation integral power qualification rate as a constraint, this invention controls battery energy storage to participate in the primary frequency regulation of wind farms through staged, graded, and continuous tracking adjustment. This effectively solves the problems of increased control system computational pressure caused by the principle of real-time tracking of primary frequency regulation demand by energy storage, and increased control difficulty of the battery itself caused by changes in energy storage output with demand. It realizes the use of supercapacitor battery energy storage to improve the primary frequency regulation control effect of wind farms, thereby improving the working efficiency and operation and maintenance safety of wind farms. Attached Figure Description

[0046] Figure 1 This is a schematic diagram of the primary frequency modulation coordinated control method based on segmented adjustment in an embodiment of the present invention;

[0047] Figure 2 This is a schematic diagram of the frequency-active power droop characteristic curve of a wind farm participating in primary frequency regulation in an embodiment of the present invention;

[0048] Figure 3 This is a schematic diagram of the energy storage output level configuration of the wind farm in an embodiment of the present invention;

[0049] Figure 4 This is a schematic diagram of the action logic principle of battery energy storage participating in the first stage of primary frequency regulation in an embodiment of the present invention;

[0050] Figure 5 This is a schematic diagram of the operational logic of battery energy storage participating in the second stage of primary frequency regulation in an embodiment of the present invention;

[0051] Figure 6 This is a schematic diagram of the action logic principle of battery energy storage participating in the third stage of primary frequency regulation in an embodiment of the present invention;

[0052] Figure 7 This is a schematic diagram of the primary frequency modulation coordinated control system structure based on segmented adjustment in an embodiment of the present invention. Detailed Implementation

[0053] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0054] Please see Figure 1 The first embodiment of the present invention proposes a primary frequency modulation coordinated control method based on segmented adjustment, comprising steps S10 to S40:

[0055] Step S10: Determine whether to trigger a primary frequency regulation action signal based on whether the grid frequency of the wind farm exceeds the primary frequency regulation dead zone of the unit.

[0056] Step S20: In response to the triggering of a primary frequency regulation action signal, determine the first battery energy storage output power based on the wind farm's required power and a number of preset battery energy storage output levels, and execute the first energy storage action.

[0057] Primary frequency regulation, as a key project in ancillary services involving the dynamic balance of active power and frequency security of the power grid, is a key assessment point of the "two detailed rules". The performance of primary frequency regulation in wind farms has a direct impact on the grid connection assessment and operating revenue of wind farms. In ancillary services, due to the significant advantages of high-rate rapid charging and discharging of supercapacitor batteries, their wide adjustable power range can be highly compatible with the needs of primary frequency regulation. Therefore, supercapacitor battery energy storage can be used to improve the primary frequency regulation control effect of wind farms. The assessment requirements of the "two detailed rules" for primary frequency regulation ancillary service projects generally use the integral power contribution rate as the assessment condition. It requires that primary frequency regulation should meet the relevant requirements of rapid action, positive output, and integral power contribution rate within a reasonable range. However, due to the high-rate rapid charging and discharging function of supercapacitor batteries, the high requirements for the speed, accuracy, and stability of grid frequency changes during the implementation of primary frequency regulation services will increase the computational pressure on the control system. In addition, the control difficulty of the battery itself will also increase due to the change of energy storage output with demand. Therefore, this invention adopts a strategy of phased adjustment and control of energy storage output to realize the function of energy storage battery participating in the primary frequency regulation control of wind farm.

[0058] First, it is determined whether to trigger a primary frequency regulation signal based on whether the grid frequency of the wind farm exceeds the primary frequency regulation dead zone of the generator. When the grid frequency exceeds the primary frequency regulation dead zone of the generator, it is determined that the wind farm needs to be regulated, and the first control stage will begin.

[0059] The first control stage in this embodiment is the energy storage rapid response stage. The main objective of this stage is to achieve a rapid and positive primary frequency regulation response from the wind farm in the initial stage of the primary frequency regulation response. However, in the initial stage of frequency overshoot, the fluctuations in both the primary frequency regulation demand power and the wind farm output can adversely affect the achievement of the rapid and positive primary frequency regulation response. Therefore, this embodiment employs energy storage output level control to ensure that the energy storage output action filters out the random reverse actions of the wind farm, thereby ensuring that the primary frequency regulation process is reasonable and effective. The specific steps are as follows:

[0060] Step S201: Select a battery energy storage output level from a number of battery energy storage output levels that is adjacent to and greater than the required power of the wind farm as the first battery energy storage output level, and use the level power and level ratio corresponding to the first battery energy storage output level as the first battery energy storage output power and the first output ratio.

[0061] Step S202: Execute the first energy storage action based on the first battery energy storage output power and the first output ratio.

[0062] Specifically, regarding the application time period issue in this stage, this embodiment uses the positive action time parameter T from the assessment of the "two detailed rules" of the wind farm's location. lag The response duration for this period is set as a reference value. For example, if the primary frequency regulation response lag time T of a new energy power station is specified... lag The response time should not exceed 2 seconds, therefore the first response time T1 in the fast response phase of energy storage should be less than T. lag Seconds, generally T1 is taken as 0 to the Tth second. lag Second.

[0063] After determining the response time, regarding the energy storage output during the rapid response phase, and considering the advantages of supercapacitor energy storage batteries—high charge / discharge rates and wide power adjustment range—this embodiment adopts a multi-level control strategy, that is, configuring the levels based on the principle of multi-level and rate allocation:

[0064] First, based on the maximum charge and discharge power P of the energy storage battery... ESPS Using different coefficients to divide multiple gears, a preferred gear division rule is to set the first gear P1 to 20% P. ESPS The second gear, P2, is set to 30% P. ESPS The third gear, P3, is set to 45% P. ESPS The fourth gear, P4, is set to 70% P. ESPS The fifth gear, P5, is set to 100% P. ESPS After the gear segmentation is completed, the multiplier M for adjacent gear segments also needs to be configured. During configuration, the suggested range of values ​​for the integral electricity contribution rate K in the local "two detailed rules" assessment requirements must also be considered (K... min K max Taking a certain location as an example, if the suggested range for the integral electricity contribution rate K is (0.6, 1.8), then within this range, a frequency regulation action assessment will not be triggered; when K is below 0.6, a single assessment will fail, triggering the assessment conditions required by the power grid; when K is above 1.8, a single accuracy assessment will fail, also triggering the assessment conditions required by the power grid. Therefore, in this embodiment, the multiplier M of adjacent gears is configured according to the multiplier expansion principle:

[0065]

[0066] In the formula, P tj To adjust the output, W represents the integral charge, and t represents time. sj W is the integral of the actual output power. xq K represents the integral electricity demanded by the wind farm, and K is the contribution rate of the integral electricity. min and K max These are the minimum and maximum values ​​of the integral electricity contribution rate, respectively.

[0067] Based on the above-mentioned multiplier configuration principles and combined with the above-mentioned gear settings, the multiplier between adjacent gears can be maintained at around 1.5 times. By reasonably configuring the gear multiplier, the integral power contribution rate K can be guaranteed during the gear adjustment process. ct Within a reasonable range, the verification principles are as follows:

[0068]

[0069]

[0070] In the formula, K ct W represents the contribution rate of electricity consumption within the adjusted time period. smin W is the extreme minimum value of the integral electric charge of the actual output. smax P is the extreme maximum value of the integral electric charge of the actual output. i This refers to the i-th gear.

[0071] By adjusting the integral electricity contribution rate K within the adjusted time period ct Within a reasonable range, the integral power contribution rate K during this frequency regulation process can be increased. c It can gradually stabilize within a reasonable range around 1.

[0072] After configuring the energy storage output ratio, the output level can be selected based on the energy storage output principle during the rapid response phase. In this phase, only frequency regulation needs are considered for energy storage output, and integral energy is not calculated. Therefore, the energy storage output principle for this phase is the "highest output principle," that is:

[0073] P i <P xq ≤P i+1

[0074] In this stage, the wind farm's power demand P is first determined. xq Determine the minimum range it falls within, and then select the larger range as the energy storage output power P according to the "choose the higher" principle. cl That is, at this time P cl P should be selected. i+1 .

[0075] In the first stage, namely the rapid response stage of energy storage, the principle of energy storage output can filter out random small fluctuations in wind farm power, ensuring the correct direction of action. The fixed gear principle can also achieve stable control of energy storage output power, reduce power fluctuations caused by short-term follow-up adjustments, and the gear appropriately exceeds the frequency regulation requirements to ensure that the integral power contribution rate is qualified, providing support for the subsequent frequency regulation action.

[0076] Step S30: In response to the execution time of the first energy storage action reaching the first response time and the grid frequency exceeding the primary frequency regulation dead zone of the unit, the second battery energy storage output power is determined based on the integral power contribution rate of the wind farm and the battery energy storage output level, and the second energy storage action is executed.

[0077] According to the control logic of the first stage, when the frequency regulation action of the first stage exceeds the preset first response time, and the grid frequency obtained in the next calculation cycle still exceeds the dead zone of the unit's primary frequency regulation, the second stage of the primary frequency regulation control process will begin, namely the integral power model prediction stage. The main objective of the integral power model prediction stage is to achieve approximate stability of the primary frequency regulation output and reserve a certain margin for integral power deviation, thus paving the way for the third stage of the primary frequency regulation process.

[0078] First, regarding the application period in this phase, the effectiveness assessment of the primary frequency regulation process in the local "two detailed rules" assessment policy will still be used as a constraint. One of the criteria for the validity of a single primary frequency regulation assessment is the effective duration T of the primary frequency regulation in a single effective assessment. hold Not less than the minimum effective duration Δt min (Generally, the value is 10 seconds). After the first stage is completed, if the frequency modulation action signal persists, the effectiveness of this frequency modulation process may be assessed. To ensure that the integral power contribution rate of this frequency modulation action is within the acceptable range, in this embodiment, the response time T2 of the integral power model prediction stage is set to the Tth... lag seconds to the Δt min Second.

[0079] Secondly, regarding the energy storage output level in this stage, in order to reduce the problem of switching energy storage levels between the two stages, the same level configuration and multiplier configuration as the first stage will still be used in this stage.

[0080] Third, regarding the energy storage output principles for this stage, these principles include the "upper limit principle" and the "upper limit adjustment principle for integral power contribution rate." The "upper limit principle" in this stage is the same as the "upper limit principle" in the first stage, which allows the energy storage output power P to be adjusted accordingly. cl The demand value P is higher than that of primary frequency regulation. xq This ensures that the output amplitude requirements are met. The specific steps for frequency regulation based on the energy storage output principle are as follows:

[0081] Step S301: Obtain the integral power contribution rate of the wind farm within the first frequency regulation, and compare the integral power contribution rate with the first contribution rate threshold.

[0082] Step S302: When the integral power contribution rate is greater than the first contribution rate threshold, the battery energy storage output level that is adjacent to the wind farm demand power and less than the wind farm demand power is taken as the second battery energy storage output level, and the level power and level multiplier corresponding to the second battery energy storage output level are taken as the second battery energy storage output power and the second output multiplier.

[0083] Step S303: Based on the second battery energy storage output power and the second output rate, execute the second energy storage action until the integral energy contribution rate is less than the second contribution rate threshold.

[0084] Step S304: In response to the integral energy contribution rate being less than the second contribution rate threshold, or when the integral energy contribution rate is less than or equal to the first contribution rate threshold, execute the first energy storage action based on the first battery energy storage output power and the first output multiplier.

[0085] In this phase, based on the integral power contribution rate K during this primary frequency regulation process... c To determine whether the current state is normal or abnormal, the corresponding energy storage output principle is selected. In the normal state, the energy storage output follows the "upper limit principle," while in the abnormal state, it follows the "lower limit principle." In this embodiment, the output principle is selected using the "integrated energy contribution rate upper limit trigger adjustment principle," specifically:

[0086] The maximum exemption value, which is also the maximum value of the contribution rate of electricity consumption, is K. max As the first contribution rate threshold, when the integral power contribution rate K in this frequency regulation process... c Not exceeding the maximum exemption value K max At this time, under normal conditions, the energy storage output principle is the "upward principle". The integrated energy will continue to increase at a rate lower than the multiplier M, thus ensuring that the integrated energy contribution rate of this integration process remains stable within (1, K). max Within the range, that is:

[0087]

[0088] When the integral power contribution rate K during this frequency regulation process c Exceeding the maximum exemption value K max When the energy storage output is in an abnormal state, it is adjusted according to the "downward principle", that is:

[0089]

[0090] The contribution rate of electricity consumption within the adjusted time period will remain at (K). min1) The principle of "adjusting the energy storage output to normal" is followed until the integral energy contribution rate during this process is lower than 1. Because K min and K max It is usually set around 1, so the principle of using 1 as the second contribution rate threshold to adjust the energy storage output can effectively maintain the stability of the integral power contribution rate.

[0091] Step S40: In response to the second energy storage action's execution duration reaching the second response duration and the grid frequency exceeding the unit's primary frequency regulation dead zone, the third battery energy storage output power is determined based on the integral power contribution rate and the preset regulation dead zone, and the third energy storage action is executed until the grid frequency recovers to the range of the unit's primary frequency regulation dead zone.

[0092] After the second stage of regulation, if the grid frequency still exceeds the unit's primary frequency regulation dead zone in the next operating cycle and its response time also reaches the preset duration, the third stage of primary frequency regulation will begin, with the steps as follows:

[0093] Step S401: Determine whether the integral power contribution rate is within the preset control dead zone. If so, use the wind farm demand power as the third battery energy storage output power. Otherwise, use the product of the wind farm demand power and the proportional coefficient as the third battery energy storage output power.

[0094] Step S402: Execute the third energy storage action according to the third battery energy storage output power.

[0095] The third stage is the energy storage accurate tracking control stage, which is the final stage of the primary frequency regulation control process. The main function of this stage is to build upon the control effects of the first two stages and achieve follow-up control. The energy storage output accurate tracking control process in this stage can ensure that the integral power contribution qualification rate is at a reasonable level at all times.

[0096] First, for the application period in this phase, the assessment requirements of the "two detailed rules" will still be used as constraints, and the minimum effective value of a single frequency modulation action, i.e., the minimum effective duration Δt, will be determined. min Using the low reference value and the end of a single frequency regulation action as the high reference value, assuming that a single effective frequency regulation process at a new energy power station should be no less than 10 seconds, then the response time T3 of the energy storage accurate following control phase should be taken as the Δt-th value. min The frequency modulation operation ends.

[0097] Secondly, regarding the energy storage output level issue in this stage, unlike the level configuration principles in the previous two stages, this stage proposes a mode of establishing an ideal integral power contribution rate dead zone. This involves setting a dead zone for the primary frequency regulation integral power contribution rate to filter out the adverse effects of small deviations in the actual primary frequency regulation response. The control dead zone can be set around 1, with a value range of (K). downLim K upLim ), which can generally be set to (0.8, 1.2).

[0098] The energy storage output principle in this stage is different from that in the previous two stages. In this stage, the normal state or the abnormal state is determined by comparing the contribution rate of the primary frequency regulation integral power with the range of the control dead zone. That is, when the contribution rate of the primary frequency regulation integral power is within the range of the control dead zone, it is a normal state, and when the contribution rate of the primary frequency regulation integral power exceeds the range of the control dead zone, it is an abnormal state.

[0099] Under normal conditions, the energy storage output adopts the "precise control principle." When the primary frequency regulation operation is in a normal state, the energy storage output tracks the primary frequency regulation demand, achieving tracking control and ensuring that the integral power contribution rate remains within a reasonable range.

[0100] K downLim <K c <K upLim

[0101] P cl =P xq

[0102] Under abnormal conditions, the energy storage output adopts the "over-limit elastic adjustment control principle." When the primary frequency regulation operation is in an abnormal state, the energy storage output undergoes moderate elastic adjustment control by adding an elastic coefficient to achieve output regulation, thereby stabilizing the integral power contribution rate during this primary frequency regulation operation at around 1. Specifically:

[0103] When the contribution rate of the primary frequency regulation integral power is low, that is:

[0104] K c ≤K downLim

[0105] At this time, the energy storage output power P cl The value should be:

[0106] P cl = (2-K) c )*P xq

[0107] Until K c When ≥1, the control logic enters the normal state.

[0108] When the contribution rate of the primary frequency modulation integral power is too high, that is:

[0109] K c ≥K upLim

[0110] At this time, the energy storage output power P cl The value should be:

[0111] P cl = (2-K) c )*P xq

[0112] Until K c When ≤1, the control logic enters the normal state.

[0113] With K c For example, P = 1.25. cl With P xq The proportionality constant is 2-K c That is, 0.75. The energy storage output value of the "over-limit flexible adjustment control principle" is corrected by adding flexible adjustment parameters, thereby achieving the goal of controlling the integral power contribution rate of the entire primary frequency regulation process within a reasonable range.

[0114] In addition, the control strategy of the present invention also needs to collect the power and frequency of the grid connection point in real time, and calculate the active power output demand of frequency regulation, the integral power contribution rate of primary frequency regulation, and the relevant parameters of the energy storage output command within the primary frequency regulation, so as to ensure the accurate implementation of the control strategy. The specific data acquisition and data processing process will not be described in detail here.

[0115] The control method provided by the present invention will be described in detail below through specific embodiments. Please refer to [link / reference]. Figure 2 The frequency-active power droop characteristic curve function of a typical wind farm participating in primary frequency regulation is shown below:

[0116]

[0117] In the formula, f d For the first frequency modulation dead zone, f N The system's rated frequency is P0, and the system's initial power is P. N δ% represents the rated power of the entire field, and δ% represents the primary frequency regulation droop rate.

[0118] Taking a certain set of characteristic parameters as an example, the primary frequency regulation related parameters are: dead zone range of 50±0.05Hz; primary frequency regulation droop rate of 3%; and primary frequency regulation load limit value of ±10%P. N The initial minimum active power of a single frequency modulation operation is 20%P. N .

[0119] Wind farms should be equipped with supercapacitor energy storage power stations, with the charging and discharging power configured according to the local primary frequency regulation load limit. Please refer to [link / reference needed]. Figure 3 For example, the local primary frequency regulation load limit is ±10%P N Then the maximum charge and discharge power of the energy storage battery configuration satisfies: P ESPS =10%P N The typical principle for expanding the output capacity of energy storage is as follows: taking a certain region as an example, the recommended range for the integral power contribution rate K is (0.6, 1.8). Energy storage participation in the primary frequency regulation process is divided into 5 levels, namely 20% P... ESPS 30% P ESPS 45% P ESPS 70% P ESPS 100% P ESPS The same applies to the forward and reverse directions of energy storage charging and discharging.

[0120] After configuration, the control logic for battery energy storage to participate in the primary frequency regulation of the wind farm is as follows: Figures 4 to 6 As shown, the logic principle of the first stage of battery energy storage participating in a frequency regulation operation is as follows: Figure 4 As shown, after the system starts up, it first collects relevant parameters such as the grid frequency and determines whether the grid frequency exceeds the unit's primary frequency regulation dead zone. When it exceeds the unit's primary frequency regulation dead zone, a primary frequency regulation action signal is triggered. At this time, the first stage of energy storage output level selection logic is executed, and energy storage action is performed. At the same time, a timer is started, and the grid frequency is continuously judged to exceed the unit's primary frequency regulation dead zone. If the grid frequency returns to the dead zone range, it means that the second stage of frequency regulation is not required. At this time, the primary frequency regulation action signal and related parameters are reset, and the timer is set to zero. If the grid frequency still exceeds the dead zone, and the cumulative duration of the timer reaches the first response duration T1, the second stage of frequency regulation is started.

[0121] Please see Figure 5 After the second phase is started, the energy storage output level selection logic that takes into account the integral power contribution rate will be executed, and the energy storage action will be performed. At the same time, the timing will start, and it will continuously judge whether the grid frequency exceeds the unit's primary frequency regulation dead zone. If the grid frequency recovers to the dead zone range, the primary frequency regulation action signal and related parameters will be reset, and the timer will be set to zero. If the grid frequency still exceeds the dead zone, and the cumulative duration of the timer reaches the second response duration T2, the third phase of frequency regulation will be started.

[0122] Please see Figure 6In the third stage, the energy storage accurate following control logic will be executed, which includes over-limit elastic adjustment control and energy storage action. At the same time, timing will start and continuously judge whether the grid frequency exceeds the unit's primary frequency regulation dead zone until the grid frequency returns to the dead zone range. The primary frequency regulation action signal and related parameters will be reset, and the timer will be set to zero to complete this primary frequency regulation action.

[0123] This embodiment provides a primary frequency regulation coordinated control method based on segmented adjustment. The invention adopts the principle of phased adjustment of energy storage batteries, setting the working mode of energy storage participation in primary frequency regulation as a coexistence of time-segmented, level-based adjustment, and continuous tracking adjustment modes. It also employs the principle of multiplier expansion for energy storage output level configuration, configuring the energy storage output level in the initial stage of primary frequency regulation by segmenting the level size in a multiplier manner. This ensures that the energy storage output is within an appropriate range, achieving initial control of the integral power contribution rate during primary frequency regulation. Furthermore, the invention uses the level adjustment principle of integral power contribution rate, logically designing the energy storage output at different stages. While ensuring the correct direction of primary frequency regulation action and that the action output meets the amplitude requirements in the initial stage, the integral power contribution rate remains stable within a reasonable range. Moreover, through precise control and over-limit elastic adjustment control after the primary frequency regulation action time exceeds the minimum effective duration, the integral power contribution rate during this effective primary frequency regulation process is maintained within the non-assessment range, further improving the control effect of wind farm primary frequency regulation.

[0124] Please see Figure 7 Based on the same inventive concept, the second embodiment of this invention proposes a primary frequency modulation coordinated control system based on segmented adjustment, comprising:

[0125] The signal triggering module 10 is used to determine whether to trigger the primary frequency regulation action signal based on whether the grid frequency of the wind farm exceeds the primary frequency regulation dead zone of the unit.

[0126] The first frequency regulation control module 20 is used to respond to the signal that triggers a primary frequency regulation action, determine the first battery energy storage output power according to the wind farm's required power and a number of preset battery energy storage output levels, and execute the first energy storage action.

[0127] The second frequency regulation control module 30 is used to respond to the first energy storage action reaching the first response time and the grid frequency exceeding the primary frequency regulation dead zone of the unit, determine the second battery energy storage output power based on the integral power contribution rate of the wind farm and the battery energy storage output level, and execute the second energy storage action.

[0128] The third frequency regulation control module 40 is used to respond to the second energy storage action reaching the second response time and the grid frequency exceeding the unit's primary frequency regulation dead zone, determine the third battery energy storage output power based on the integral power contribution rate and the preset regulation dead zone, and execute the third energy storage action until the grid frequency recovers to the range of the unit's primary frequency regulation dead zone.

[0129] Furthermore, the first frequency modulation control module 20 includes a first output power determination module 201 and a first energy storage control module 202;

[0130] The first output power determination module 201 is used to select from a plurality of battery energy storage output power levels a battery energy storage output power level that is adjacent to and greater than the wind farm's required power level as the first battery energy storage output power level, and to use the power level and the power level ratio corresponding to the first battery energy storage output power level as the first battery energy storage output power and the first output power ratio.

[0131] The first energy storage control module 202 executes a first energy storage action based on the first battery energy storage output power and the first output ratio.

[0132] Furthermore, the second frequency modulation control module 30 includes a second output power determination module 301 and a second energy storage control module 302;

[0133] The second output power determination module 302 is used to obtain the integral power contribution rate of the wind farm within the first frequency regulation, and compare the integral power contribution rate with the first contribution rate threshold.

[0134] When the integral power contribution rate is greater than the first contribution rate threshold, the battery energy storage output level that is adjacent to the wind farm's demand power and less than the wind farm's demand power is taken as the second battery energy storage output level, and the level power and level multiplier corresponding to the second battery energy storage output level are taken as the second battery energy storage output power and the second output multiplier.

[0135] The second energy storage control module 302 is used to execute a second energy storage action based on the second battery energy storage output power and the second output rate, until the integral energy contribution rate is less than the second contribution rate threshold.

[0136] In response to the integral energy contribution rate being less than the second contribution rate threshold, or when the integral energy contribution rate is less than or equal to the first contribution rate threshold, a first energy storage action is performed based on the first battery energy storage output power and the first output rate.

[0137] Furthermore, the third frequency modulation control module 40 includes a third output power determination module 401 and a third energy storage control module 402;

[0138] The third output power determination module 402 is used to determine whether the integral power contribution rate is within the preset control dead zone. If so, the wind farm demand power is used as the third battery energy storage output power; otherwise, the product of the wind farm demand power and the proportional coefficient is used as the third battery energy storage output power.

[0139] The third energy storage control module 402 is used to execute the third energy storage action according to the third battery energy storage output power.

[0140] The technical features and effects of the primary frequency modulation coordinated control system based on segmented adjustment proposed in this invention are the same as those of the method proposed in this invention, and will not be repeated here. Each module in the above-mentioned primary frequency modulation coordinated control system based on segmented adjustment can be implemented entirely or partially through software, hardware, or a combination thereof. Each module can be embedded in or independent of the processor in a computer device in hardware form, or stored in the memory of a computer device in software form, so that the processor can call and execute the operations corresponding to each module.

[0141] In summary, the present invention proposes a primary frequency regulation coordinated control method and system based on segmented adjustment. The method determines whether a primary frequency regulation action signal is triggered based on whether the grid frequency of the wind farm exceeds the primary frequency regulation dead zone of the turbine. In response to triggering the primary frequency regulation action signal, a first battery energy storage output power is determined based on the wind farm's required power and several preset battery energy storage output levels, and a first energy storage action is executed. In response to the execution duration of the first energy storage action reaching a first response duration, and the grid frequency exceeding the primary frequency regulation dead zone of the turbine, a second battery energy storage output power is determined based on the wind farm's integral power contribution rate and the battery energy storage output level, and a second energy storage action is executed. In response to the execution duration of the second energy storage action reaching a second response duration, and the grid frequency exceeding the primary frequency regulation dead zone of the turbine, a third battery energy storage output power is determined based on the integral power contribution rate and a preset control dead zone, and a third energy storage action is executed, until the grid frequency recovers to within the range of the turbine's primary frequency regulation dead zone. This invention adopts the principle of adjusting the integral power contribution rate, and makes logical designs for the energy storage output at different stages. On the basis of ensuring that the direction of the primary frequency regulation action is correct and the output of the action meets the amplitude requirements in the initial stage, the integral power contribution rate is kept stable within a reasonable range. Furthermore, through precise control and over-limit elastic adjustment control after the primary frequency regulation action time exceeds the minimum effective duration, it ensures that the integral power contribution rate in this effective primary frequency regulation process is maintained within the assessment-free range, further improving the control effect of the primary frequency regulation of the wind farm.

[0142] The various embodiments in this specification are described in a progressive manner. For directly identical or similar parts of the embodiments, refer to each other. Each embodiment focuses on its differences from other embodiments. In particular, the system embodiments are basically similar to the method embodiments, so the description is relatively simple; relevant parts can be referred to the descriptions in the method embodiments. It should be noted that the technical features of the above embodiments can be combined arbitrarily. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as the combination of these technical features does not contradict each other, it should be considered within the scope of this specification.

[0143] The embodiments described above are merely preferred embodiments of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various improvements and substitutions without departing from the technical principles of this invention, and these improvements and substitutions should also be considered within the scope of protection of this application. Therefore, the scope of protection of this patent application should be determined by the scope of the claims.

Claims

1. A primary frequency modulation coordinated control method based on segmented adjustment, characterized in that, include: Determine whether to trigger a primary frequency regulation action signal based on whether the grid frequency of the wind farm exceeds the primary frequency regulation dead zone of the unit; In response to a signal triggering a frequency regulation action, based on the wind farm's power demand and several preset battery energy storage output levels, the first battery energy storage output power is determined, and the first energy storage action is executed, including: Select a battery energy storage output level from a number of battery energy storage output levels that is adjacent to and greater than the required power of the wind farm as the first battery energy storage output level, and use the level power and level ratio corresponding to the first battery energy storage output level as the first battery energy storage output power and the first output ratio. The first energy storage action is executed based on the first battery energy storage output power and the first output ratio; In response to the execution time of the first energy storage action reaching the first response time, and the grid frequency exceeding the primary frequency regulation dead zone of the generator unit, the second battery energy storage output power is determined based on the wind farm's integral power contribution rate and the battery energy storage output level, and the second energy storage action is executed, including: When the integral power contribution rate is greater than the first contribution rate threshold, the battery energy storage output level that is adjacent to the wind farm's demand power and less than the wind farm's demand power is taken as the second battery energy storage output level, and the level power and level multiplier corresponding to the second battery energy storage output level are taken as the second battery energy storage output power and the second output multiplier. The second energy storage action is executed based on the second battery energy storage output power and the second output rate; In response to the second energy storage action reaching the second response time and the grid frequency exceeding the unit's primary frequency regulation dead zone, the third battery energy storage output power is determined based on the integral power contribution rate and the preset regulation dead zone, and the third energy storage action is executed until the grid frequency recovers to the range of the unit's primary frequency regulation dead zone.

2. The primary frequency modulation coordinated control method based on segmented adjustment according to claim 1, characterized in that, The step of determining the second battery energy storage output power based on the wind farm's integral power contribution rate and the battery energy storage output level, and then executing the second energy storage action, further includes: In response to the integral energy contribution rate being less than the second contribution rate threshold, or when the integral energy contribution rate is less than or equal to the first contribution rate threshold, a first energy storage action is performed based on the first battery energy storage output power and the first output rate.

3. The primary frequency modulation coordinated control method based on segmented adjustment according to claim 2, characterized in that, The steps of determining the third battery energy storage output power based on the integral energy contribution rate and the preset control dead zone, and executing the third energy storage action, include: Determine whether the integral power contribution rate is within the preset control dead zone. If so, use the wind farm demand power as the third battery energy storage output power; otherwise, use the product of the wind farm demand power and the proportional coefficient as the third battery energy storage output power. The third energy storage action is executed based on the third battery energy storage output power.

4. The primary frequency modulation coordinated control method based on segmented adjustment according to claim 1, characterized in that, Before determining whether to trigger a primary frequency regulation action signal based on whether the grid frequency of the wind farm exceeds the primary frequency regulation dead zone of the generator, the method further includes: The grid power and grid frequency of the wind farm are collected in real time, and the wind farm's demand power and integral power contribution rate within the primary frequency regulation are calculated based on the grid power and grid frequency.

5. The primary frequency modulation coordinated control method based on segmented adjustment according to claim 3, characterized in that, The duration of the first response is determined by the forward action time parameter; The second response duration is determined by the positive action time parameter and the lowest effective value of the first frequency modulation action; The first contribution rate threshold is determined by the maximum exemption value; The second contribution rate threshold is determined by the minimum exemption value and the maximum exemption value; The proportionality coefficient is determined by the integral power contribution rate.

6. A primary frequency modulation coordinated control system based on segmented adjustment, characterized in that, include: The signal triggering module is used to determine whether to trigger the primary frequency regulation action signal based on whether the grid frequency of the wind farm exceeds the primary frequency regulation dead zone of the unit; The first frequency regulation control module is used to respond to the signal that triggers a primary frequency regulation action, determine the first battery energy storage output power based on the wind farm's required power and several preset battery energy storage output levels, and execute the first energy storage action. The second frequency regulation control module is used to respond to the first energy storage action reaching the first response time and the grid frequency exceeding the primary frequency regulation dead zone of the unit, determine the second battery energy storage output power based on the wind farm's integral power contribution rate and the battery energy storage output level, and execute the second energy storage action. The third frequency regulation control module is used to respond to the second energy storage action reaching the second response time and the grid frequency exceeding the unit's primary frequency regulation dead zone, determine the third battery energy storage output power based on the integral power contribution rate and the preset regulation dead zone, and execute the third energy storage action until the grid frequency recovers to the range of the unit's primary frequency regulation dead zone. The first frequency modulation control module includes a first output power determination module and a first energy storage control module; The first output power determination module is used to select from a plurality of battery energy storage output power levels a battery energy storage output power level that is adjacent to and greater than the wind farm's required power level as the first battery energy storage output power level, and to use the power level and the power level ratio corresponding to the first battery energy storage output power level as the first battery energy storage output power and the first output power ratio. The first energy storage control module executes a first energy storage action based on the first battery energy storage output power and the first output ratio; The second frequency modulation control module includes a second output power determination module and a second energy storage control module; The second output power determination module is used to, when the integral power contribution rate is greater than the first contribution rate threshold, take the battery energy storage output level that is adjacent to the wind farm demand power and less than the wind farm demand power as the second battery energy storage output level, and take the level power and level multiplier corresponding to the second battery energy storage output level as the second battery energy storage output power and the second output multiplier. The second energy storage control module is used to execute a second energy storage action based on the energy storage output power of the second battery and the second output rate.

7. The primary frequency modulation coordinated control system based on segmented adjustment according to claim 6, characterized in that, The second energy storage control module is used to perform a first energy storage action based on the first battery energy storage output power and the first output multiplier when the integral energy contribution rate is less than a second contribution rate threshold, or when the integral energy contribution rate is less than or equal to a first contribution rate threshold.

8. The primary frequency modulation coordinated control system based on segmented adjustment according to claim 7, characterized in that, The third frequency modulation control module includes a third output power determination module and a third energy storage control module; The third output power determination module is used to determine whether the integral power contribution rate is within the preset control dead zone. If so, the wind farm demand power is used as the third battery energy storage output power; otherwise, the product of the wind farm demand power and the proportional coefficient is used as the third battery energy storage output power. The third energy storage control module is used to execute the third energy storage action according to the energy output power of the third battery.

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