A control method and system for primary frequency modulation

Abstract

The present invention provides a control method and system for primary frequency modulation, which relates to the technical field of power grid frequency modulation. The method includes: obtaining the historical probability distribution of the primary frequency modulation time, and determining the corresponding primary frequency modulation time according to the preset probability and the historical probability distribution; obtaining the expected number of primary frequency modulations and the rated capacity of the energy storage, and determining the upper and lower boundaries of the primary frequency modulation support capability level according to the expected number of primary frequency modulations, the rated capacity of the energy storage and the primary frequency modulation time; obtaining the current SOC, comparing the SOC with the upper and lower boundaries, and controlling the charging and discharging of the energy storage according to the comparison result. The technical solution described in the present invention can determine the current frequency modulation support capability level according to the SOC obtained in real time, control the energy storage to charge or discharge, and thus reserve a larger adjustment space for the energy storage, which is conducive to improving the support capability of the energy storage for the primary frequency modulation response, and achieving the purpose of having the ability to support primary frequency modulation at any time.

Description

Technical Field

[0001] The present invention relates to the technical field of power grid frequency regulation, and in particular to a control method and system for primary frequency regulation. Background Art

[0002] The addition of distributed energy resources poses certain risks to the power grid. To address this risk, the power system's inherent load-frequency characteristics and the generator set's speed regulator are often leveraged to adjust the power system's frequency, also known as primary frequency regulation. Currently, new energy stations typically utilize energy storage for primary frequency regulation, but this cannot support primary frequency regulation when the energy storage is fully charged or empty. Summary of the Invention

[0003] The problem solved by the present invention is how to ensure that energy storage always has primary frequency regulation capability.

[0004] To solve the above problems, the present invention provides a primary frequency modulation control method, comprising: obtaining a historical probability distribution of a primary frequency modulation time, and determining a corresponding primary frequency modulation time according to a preset probability and the historical probability distribution; obtaining an expected number of primary frequency modulations and a rated capacity of an energy storage device, and determining an upper limit and a lower limit of a primary frequency modulation support capability level according to the expected number of primary frequency modulations, the rated capacity of the energy storage device, and the primary frequency modulation time; obtaining a current state of charge (SOC), comparing the SOC with the upper limit and the lower limit, and controlling the charging and discharging of the energy storage device according to the comparison result.

[0005] The primary frequency modulation control method described in the present invention determines the primary frequency modulation time based on the historical probability distribution of the primary frequency modulation time, thereby determining the upper and lower boundaries of the primary frequency modulation support capability level. Furthermore, the current frequency modulation support capability level can be determined based on the SOC acquired in real time. The charging or discharging of energy storage is controlled to reserve a larger adjustment space for the energy storage, which is beneficial to improving the energy storage's support capability for primary frequency modulation response and achieving the goal of having the ability to support primary frequency modulation at any time.

[0006] Optionally, determining the corresponding frequency modulation time according to the preset probability and the historical probability distribution includes: determining the i-th frequency modulation time Ti corresponding to the i-th preset probability Pi according to the historical probability distribution, where i=1,2,...,n,n≥3, P1<P2<...<Pi, T1<T2<...<Ti.

[0007] The primary frequency modulation control method described in the present invention determines the i-th frequency modulation time Ti corresponding to the i-th preset probability Pi according to the historical probability distribution, so that the corresponding first-level, second-level, and n-level upper boundaries and first-level, second-level, and n-level lower boundaries can be determined according to T1, T2, and Tn, so as to determine the current frequency modulation support capability level according to the real-time acquired SOC, thereby realizing refined control of energy storage.

[0008] Optionally, determining the upper and lower boundaries of the primary frequency regulation support capability level according to the expected number of primary frequency regulation times, the energy storage rated capacity, and the primary frequency regulation time includes:

[0009] The SOC corresponding to the lower boundary is determined according to a first formula, wherein the first formula includes:

[0010]

[0011] Among them, SOCi represents the SOC corresponding to the lower boundary of level i, SOC1<SOC2<SOC3, SOC L represents the lower boundary protection value of energy storage, E represents the expected number of frequency modulation times, T i represents the frequency regulation time, Pn represents the rated capacity of the photovoltaic power station, 10%*Pn represents the maximum frequency regulation output, and C represents the rated capacity of the energy storage.

[0012] The primary frequency modulation control method described in the present invention determines SOC1, SOC2 and SOC3 corresponding to the lower boundaries of the first, second and third levels according to the first formula, so that the current frequency modulation support capability level can be determined according to the SOC obtained in real time, thereby realizing refined control of energy storage.

[0013] Optionally, determining the upper and lower boundaries of the primary frequency regulation support capability level according to the expected number of primary frequency regulation times, the rated capacity of the energy storage, and the primary frequency regulation time further includes:

[0014] The SOC corresponding to the upper limit is determined according to a second formula, wherein the second formula includes:

[0015]

[0016] Among them, SOCi' represents the SOC corresponding to the upper boundary of level i, SOC H Indicates the upper boundary protection value of energy storage.

[0017] The primary frequency modulation control method described in the present invention determines SOC1', SOC2' and SOC3' corresponding to the upper boundaries of the first, second and third levels according to the second formula, so that the current frequency modulation support capability level can be determined according to the SOC obtained in real time, thereby realizing refined control of energy storage.

[0018] Optionally, comparing the SOC with the upper boundary and the lower boundary and controlling the charging and discharging of the energy storage according to the comparison result includes: when the SOC is less than SOC3, controlling the energy storage to charge; when the SOC is greater than SOC3 and less than SOC3', controlling the energy storage to not operate; when the SOC is greater than SOC3', controlling the energy storage to discharge.

[0019] The primary frequency modulation control method described in the present invention determines the current frequency modulation support capability level based on a comparison of the real-time acquired SOC with the upper and lower boundaries, and adjusts the energy storage to perform corresponding charging and discharging actions, thereby reserving a larger adjustment space for the energy storage, achieving refined control of the energy storage, and facilitating improved support capabilities of the energy storage for primary frequency modulation responses.

[0020] Optionally, when the SOC is less than SOC3, controlling energy storage charging includes:

[0021] When the SOC satisfies 0<SOC<SOC1, controlling the energy storage to charge until the SOC reaches SOC1, SOC2 or SOC3;

[0022] When the SOC satisfies SOC1<SOC<SOC2, controlling the energy storage to charge until the SOC reaches SOC2 or SOC3;

[0023] When the SOC satisfies SOC2<SOC<SOC3, controlling the energy storage to charge until the SOC reaches SOC3 or not taking any action;

[0024] When the SOC is greater than SOC3', controlling the energy storage discharge includes:

[0025] When the SOC satisfies SOC3'<SOC<SOC2', the energy storage is controlled to discharge until the SOC reaches SOC3' or no action is taken;

[0026] When the SOC satisfies SOC2'<SOC<SOC1', controlling the energy storage to discharge until the SOC reaches SOC2' or SOC3';

[0027] When the SOC satisfies SOC1'<SOC, the stored energy is controlled to discharge until the SOC reaches SOC1', SOC2' or SOC3'.

[0028] The primary frequency modulation control method described in the present invention determines the corresponding SOC level based on the comparison of the real-time acquired SOC with the upper and lower boundaries, determines the current frequency modulation support capability level based on the SOC level, and adjusts the energy storage to perform corresponding charging and discharging operations, thereby reserving a larger adjustment space for the energy storage, realizing refined control of the energy storage, and facilitating improving the energy storage's support capability for the primary frequency modulation response.

[0029] Optionally, the primary frequency modulation control method further includes: controlling the energy storage to charge until the SOC reaches SOC corresponding to different lower boundaries, or controlling the energy storage to discharge until the SOC reaches SOC corresponding to different upper boundaries according to a set failure rate of the primary frequency modulation.

[0030] The primary frequency modulation control method described in the present invention determines the SOC corresponding to different boundaries when charging or discharging energy storage by setting a set failure rate, thereby reserving a larger adjustment space for energy storage and facilitating improving the energy storage's ability to support primary frequency modulation response.

[0031] Optionally, the primary frequency modulation control method further includes:

[0032] When a primary frequency modulation occurs, the primary frequency modulation amount is determined according to a third formula, wherein the third formula includes:

[0033]

[0034] in, △ P represents the primary frequency modulation amount, f H 、f L They represent the upper and lower dead zones of primary frequency modulation, respectively. N represents the rated frequency of the photovoltaic power station, f represents the real-time monitoring frequency, δ 上 , δ 下 They represent the up-regulation rate and down-regulation rate of the fast frequency modulation response respectively.

[0035] The primary frequency modulation control method described in the present invention determines the primary frequency modulation amount through the third formula and adjusts the energy storage to perform corresponding charging and discharging actions, thereby reserving a larger adjustment space for the energy storage, realizing refined control of the energy storage, and facilitating improving the energy storage's ability to support the primary frequency modulation response.

[0036] Optionally, the primary frequency modulation control method further includes: optimizing the historical probability distribution by self-learning.

[0037] The primary frequency modulation control method of the present invention optimizes the historical probability distribution through self-learning, which is beneficial to improving the accuracy of the upper and lower boundaries, thereby improving the support capability of energy storage for the primary frequency modulation response.

[0038] Optionally, the primary frequency modulation control method further includes: adjusting the historical probability distribution according to the season.

[0039] The primary frequency modulation control method of the present invention adjusts the historical probability distribution according to the season, which is beneficial to improving the accuracy of the upper and lower boundaries, thereby improving the support capability of energy storage for the primary frequency modulation response.

[0040] The present invention also provides a primary frequency modulation control system, comprising a computer-readable storage medium storing a computer program and a processor. When the computer program is read and executed by the processor, the primary frequency modulation control method described above is implemented. The primary frequency modulation control system has the same advantages as the primary frequency modulation control method described above over the prior art, and will not be further elaborated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 Schematic diagram of the flow of a method for controlling primary frequency modulation according to an embodiment of the present invention;

[0042] Figure 2 Schematic diagram of the system architecture of an embodiment of the present invention;

[0043] Figure 3 is a droop curve of a primary frequency modulation response according to an embodiment of the present invention;

[0044] Figure 4 Schematic diagram of a primary frequency modulation control system according to an embodiment of the present invention. DETAILED DESCRIPTION

[0045] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0046] like Figure 1 As shown, an embodiment of the present invention provides a primary frequency modulation control method, including: obtaining a historical probability distribution of a primary frequency modulation time, and determining a corresponding primary frequency modulation time according to a preset probability and the historical probability distribution; obtaining an expected number of primary frequency modulations and a rated capacity of an energy storage, and determining an upper limit and a lower limit of a primary frequency modulation support capability level according to the expected number of primary frequency modulations, the rated capacity of the energy storage, and the primary frequency modulation time; obtaining a current SOC, comparing the SOC with the upper limit and the lower limit, and controlling the charging and discharging of the energy storage according to the comparison result.

[0047] Specifically, in this embodiment, the control method for a single frequency modulation includes: obtaining a historical probability distribution of a single frequency modulation time, the historical probability distribution being the distribution statistics of past single frequency modulation times, and the form of the distribution statistics can be a normal distribution, or a non-normal chi-square distribution, a T distribution, or an F distribution. Taking the normal distribution as an example, in the normal distribution of the single frequency modulation time, the area represents the probability, so the corresponding single frequency modulation time can be determined based on the preset probability and the historical probability distribution. After determining the single frequency modulation time, the upper and lower boundaries of the single frequency modulation can be determined in combination with the expected number of single frequency modulations and the rated capacity of the energy storage, and then the current frequency modulation support capability level can be determined based on the SOC (State of Charge) obtained in real time. Different levels correspond to different energy storage charging and discharging strategies, so that the energy storage can provide support when a single frequency modulation occurs, thereby achieving the purpose of having the ability to support single frequency modulation at any time.

[0048] The upper and lower boundaries are the classification criteria for primary frequency regulation support capability levels, and serve as the limits for energy storage discharge and charging, respectively, enabling refined control of energy storage.

[0049] Combine Figure 2 As shown, taking a photovoltaic system as an example, a storage grid connection point, an energy storage system, and a corresponding controller are usually set up. In addition, this embodiment is not limited to multi-distributed + energy storage or independent energy storage.

[0050] In this embodiment, the primary frequency modulation time is determined based on the historical probability distribution of the primary frequency modulation time, thereby determining the upper and lower bounds of the primary frequency modulation support capability level. Furthermore, the current frequency modulation support capability level can be determined based on the SOC acquired in real time. The charging or discharging of the energy storage is controlled to reserve a larger adjustment space for the energy storage, which is beneficial to improving the energy storage's support capability for the primary frequency modulation response and achieving the goal of having the ability to support primary frequency modulation at any time.

[0051] Optionally, determining the corresponding frequency modulation time according to the preset probability and the historical probability distribution includes: determining the i-th frequency modulation time Ti corresponding to the i-th preset probability Pi according to the historical probability distribution, where i=1,2,...,n,n≥3, P1<P2<...<Pi, T1<T2<...<Ti.

[0052] Specifically, in this embodiment, determining the corresponding frequency regulation time according to the preset probability and the historical probability distribution includes: taking the normal distribution as an example, performing normal distribution statistics on the previous frequency regulation adjustment times, taking n=3 as an example, i can be 1, 2 and 3, and statistically calculating the adjustment times T1, T2 and T3 corresponding to the probabilities P1, P2 and P3 (where P1<P2<P3, T1<T2<T3), so that the corresponding first-level, second-level and third-level upper boundaries and the first-level, second-level and third-level lower boundaries can be determined according to T1, T2 and T3, so as to determine the current frequency regulation support capability level according to the SOC value obtained in real time, thereby realizing refined control of energy storage.

[0053] Among them, when performing normal distribution probability analysis on historical frequency modulation time, it is necessary to eliminate outlier data.

[0054] In this embodiment, the i-th frequency modulation time Ti corresponding to the i-th preset probability Pi is determined respectively according to the historical probability distribution, so that the corresponding first-level, second-level, and n-level upper boundaries and first-level, second-level, and n-level lower boundaries can be determined according to T1, T2, and Tn, so as to determine the current frequency modulation support capability level according to the real-time acquired SOC, thereby realizing refined control of energy storage.

[0055] Optionally, determining the upper and lower boundaries of the primary frequency regulation support capability level according to the expected number of primary frequency regulation times, the energy storage rated capacity, and the primary frequency regulation time includes:

[0056] The SOC corresponding to the lower boundary is determined according to a first formula, wherein the first formula includes:

[0057]

[0058] Among them, SOCi represents the SOC corresponding to the lower boundary of level i, SOC1<SOC2<SOC3, SOC L represents the lower boundary protection value of energy storage, E represents the expected number of frequency modulation times, T i represents the frequency regulation time, Pn represents the rated capacity of the photovoltaic power station, 10%*Pn represents the maximum frequency regulation output, and C represents the rated capacity of the energy storage.

[0059] Specifically, in this embodiment, the lower boundary is determined according to the first formula:

[0060]

[0061] Among them, SOCi represents the SOC value corresponding to the lower boundary of level i, SOC L It represents the lower boundary protection value of energy storage (setting purpose: to prevent excessive discharge), E represents the expected number of frequency modulations, T i It represents the frequency regulation time, Pn represents the rated capacity of the photovoltaic power station, 10%*Pn represents the maximum frequency regulation output, and C represents the rated capacity of the energy storage.

[0062] In the first formula, the denominator of the fraction on the right represents the total capacity, and the numerator represents the charge and discharge amount within the E frequency modulation time. The difference between the two is the charge size SOC, which is then added to the lower boundary protection value of the energy storage to determine the SOC1, SOC2 and SOC3 corresponding to the first, second and third level lower boundaries (SOC1<SOC2<SOC3. If SOC3 is greater than 50%, SOC3 needs to be equal to 50%).

[0063] When there is high-frequency interference, the primary frequency modulation needs to reduce power. For the source of the photovoltaic power station, reducing power is equivalent to reducing the power of the grid connection point by reducing energy storage discharge or energy storage charging. When using energy storage charging to reduce the active power of the station, it is necessary to ensure that the energy storage has charging capacity, so a certain amount of space needs to be reserved. The battery cannot be fully charged, so that the battery has no charging capacity, resulting in the failure of the primary frequency modulation.

[0064] Among them, combined Figure 3 As shown (P0 represents the initial value of active power, f +d and f -d Indicates the primary frequency modulation dead zone, f min and f max Respectively represent the corresponding thresholds), the maximum output of frequency modulation represents the upper and lower limits of frequency modulation, which can be 10%*Pn and -10%*Pn respectively, but 10% is not fixed and can be set according to the actual situation in different regions. The upper limit of frequency modulation can be set according to the maximum output of frequency modulationup (positive value) and lower limit amplitude PP down (negative value), when the frequency modulation △ P satisfies △P>PP up When PP up Assign △P as the target power regulation, when △P<PP down When PP down Assign a value to △P as the target power regulation.

[0065] In this embodiment, SOC1, SOC2 and SOC3 corresponding to the lower boundaries of level 1, level 2 and level 3 are determined according to the first formula, so that the current frequency regulation support capability level can be determined according to the real-time acquired SOC, thereby realizing refined control of energy storage.

[0066] Optionally, determining the upper and lower boundaries of the primary frequency regulation support capability level according to the expected number of primary frequency regulation times, the rated capacity of the energy storage, and the primary frequency regulation time further includes:

[0067] The SOC corresponding to the upper limit is determined according to a second formula, wherein the second formula includes:

[0068]

[0069] Among them, SOCi' represents the SOC corresponding to the upper boundary of level i, SOC3'<SOC2'<SOC1', SOC H Indicates the upper boundary protection value of energy storage (setting purpose: to prevent overcharging).

[0070] Specifically, in this embodiment, the upper boundary is determined according to the second formula:

[0071]

[0072] Among them, SOCi' represents the SOC corresponding to the upper boundary of level i, SOC H Indicates the upper boundary protection value of energy storage.

[0073] In the second formula, the denominator of the fraction on the right represents the total capacity, and the numerator represents the charge and discharge amount within the frequency modulation time E times. The difference between the two is the charge size SOC, which is then subtracted from the upper boundary protection value of the energy storage to determine the SOC1', SOC2' and SOC3' corresponding to the first, second and third level upper boundaries (SOC3'<SOC2'<SOC1').

[0074] In this embodiment, SOC1', SOC2' and SOC3' corresponding to the upper boundaries of the first, second and third levels are determined according to the second formula, so that the current frequency regulation support capability level can be determined according to the real-time acquired SOC, thereby achieving refined control of energy storage.

[0075] Optionally, comparing the SOC with the upper boundary and the lower boundary and controlling the charging and discharging of the energy storage according to the comparison result includes: when the SOC is less than SOC3, controlling the energy storage to charge; when the SOC is greater than SOC3 and less than SOC3', controlling the energy storage to not operate; when the SOC is greater than SOC3', controlling the energy storage to discharge.

[0076] Specifically, in this embodiment, when the SOC is less than SOC3, the current energy storage's ability to support the primary frequency regulation is insufficient, and the energy storage is controlled to charge. When the SOC is greater than SOC3 and less than SOC3', the energy storage's ability to support the primary frequency regulation is at a reasonable level, and the energy storage is controlled not to operate. When the SOC is greater than SOC3', the current energy storage's ability to support the primary frequency regulation is insufficient, and the energy storage is controlled to discharge.

[0077] In this embodiment, the current frequency regulation support capability level is determined based on a comparison between the real-time SOC and the upper and lower boundaries, and the energy storage is adjusted to perform corresponding charging and discharging actions, thereby reserving a larger adjustment space for the energy storage, achieving refined control of the energy storage, and facilitating improved support capabilities of the energy storage for primary frequency regulation response.

[0078] Optionally, when the SOC is less than SOC3, controlling energy storage charging includes:

[0079] When the SOC satisfies 0<SOC<SOC1, controlling the energy storage to charge until the SOC reaches SOC1, SOC2 or SOC3;

[0080] When the SOC satisfies SOC1<SOC<SOC2, controlling the energy storage to charge until the SOC reaches SOC2 or SOC3;

[0081] When the SOC satisfies SOC2<SOC<SOC3, controlling the energy storage to charge until the SOC reaches SOC3 or not taking any action;

[0082] When the SOC is greater than SOC3', controlling the energy storage discharge includes:

[0083] When the SOC satisfies SOC3'<SOC<SOC2', the energy storage is controlled to discharge until the SOC reaches SOC3' or no action is taken;

[0084] When the SOC satisfies SOC2'<SOC<SOC1', controlling the energy storage to discharge until the SOC reaches SOC2' or SOC3';

[0085] When the SOC satisfies SOC1'<SOC, the stored energy is controlled to discharge until the SOC reaches SOC1', SOC2' or SOC3'.

[0086] Specifically, in this embodiment, the SOC of the energy storage system is monitored in real time to determine the relationship between the SOC and SOC1, SOC2, SOC3, SOC1', SOC2' and SOC3'. When in different ranges, different energy storage control actions are prompted, specifically:

[0087] (1) When the SOC satisfies 0<SOC<SOC1, it is a serious reminder that the energy storage needs to be charged. The current energy storage only has the ability to support frequency regulation once at the first level. At this time, the energy storage charging SOC is controlled to reach SOC1, SOC2 or SOC3;

[0088] (2) When the SOC satisfies SOC1<SOC<SOC2, it is important to remind the energy storage to be charged. The current energy storage only has the secondary upper regulation and single frequency regulation support capability. At this time, the energy storage is controlled to charge until the SOC reaches SOC2 or SOC3;

[0089] (3) When the SOC satisfies SOC2<SOC<SOC3, it is generally indicated that the energy storage needs to be charged. The current energy storage has the ability to support three-level upper regulation and primary frequency regulation. At this time, the energy storage is controlled to charge until the SOC reaches SOC3 or no action is taken;

[0090] (4) When the SOC satisfies SOC3<SOC<SOC3', no energy storage prompt is given, and the energy storage control does not operate;

[0091] (5) When the SOC satisfies SOC3'<SOC<SOC2', it is generally indicated that the energy storage needs to be discharged. The current energy storage has the ability to support the three-level down-regulation of the primary frequency regulation. At this time, the energy storage is controlled to discharge until the SOC reaches SOC3' or no action is taken;

[0092] (6) When the SOC satisfies SOC2'<SOC<SOC1', it is important to remind the energy storage to discharge. The current energy storage only has the secondary down-regulation and single frequency modulation support capability. At this time, the energy storage is controlled to discharge until the SOC reaches SOC2' or SOC3';

[0093] (7) When the SOC satisfies SOC1'<SOC, it is a serious reminder that the energy storage needs to be discharged. The current energy storage has only the ability to support frequency regulation once at the first level. At this time, the energy storage is controlled to discharge until the SOC reaches SOC1', SOC2' or SOC3'.

[0094] Among them, when a serious warning alarm is reported, taking the above adjustment as an example, the energy storage can be controlled to charge to SOC1, SOC2, or SOC3, which depends on the set P1, P2 and P3, and whether the failure rate of 1-P1, 1-P2 and 1-P3 frequency adjustment E times per day can be tolerated.

[0095] Among them, when an important reminder alarm is reported, taking the above adjustment as an example, the energy storage can be controlled to charge to SOC2 or SOC3, which depends on whether the set P2 and P3 can tolerate a 1-P2 probability and a 1-P3 probability of E frequency adjustment failures throughout the day.

[0096] Among them, when a general prompt alarm is reported, taking the above adjustment as an example, the energy storage can be controlled to charge to SOC3, or no action can be taken. This depends on the set P3 and whether it can tolerate a failure rate of 1-P3 probability of one frequency adjustment E times throughout the day.

[0097] In this embodiment, the corresponding SOC level is determined based on the comparison between the real-time SOC and the upper and lower boundaries. The current frequency regulation support capability level is determined based on the SOC level, and the energy storage is adjusted to perform corresponding charging and discharging operations. This reserves a larger adjustment space for the energy storage, realizes refined control of the energy storage, and is conducive to improving the energy storage's support capability for primary frequency regulation response.

[0098] Optionally, the primary frequency modulation control method further includes: controlling the energy storage to charge until the SOC reaches SOC corresponding to different lower boundaries, or controlling the energy storage to discharge until the SOC reaches SOC corresponding to different upper boundaries according to a set failure rate of the primary frequency modulation.

[0099] Specifically, in this embodiment, the energy storage is allowed to fail in a single frequency adjustment, but it is not required to support single frequency adjustment 100%. When a serious warning alarm is reported, taking the above adjustment as an example, the energy storage can be controlled to charge to SOC1, SOC2, or SOC3. This depends on the set P1, P2, and P3, and whether the failure rate of 1-P1, 1-P2, and 1-P3 in a single frequency adjustment of E times throughout the day can be tolerated. If the tolerance for the failure rate is high and a certain degree of failure can be allowed, it is sufficient to charge to SOC1 during the upward adjustment. If a large failure rate is not allowed, it is charged to SOC3 during the upward adjustment, thereby reserving a larger adjustment space for the energy storage and making the failure rate of the single frequency adjustment lower.

[0100] In this embodiment, the energy storage is charged or discharged to the SOC corresponding to different boundaries by setting a set failure rate, which reserves a larger adjustment space for the energy storage, and is conducive to improving the energy storage's support capability for primary frequency modulation response.

[0101] Optionally, the primary frequency modulation control method further includes:

[0102] When a primary frequency modulation occurs, the primary frequency modulation amount is determined according to a third formula, wherein the third formula includes:

[0103]

[0104] in, △P represents the primary frequency modulation amount, f H 、f L They represent the upper and lower dead zones of primary frequency modulation, respectively. N represents the rated frequency of the photovoltaic power station, f represents the real-time monitoring frequency, δ 上 , δ 下 They represent the up-regulation rate and down-regulation rate of the fast frequency modulation response respectively.

[0105] Specifically, in this embodiment, the frequency f, active power, current SOC of the energy storage, fault status of the energy storage system, frequency, power, voltage and other data of the total grid connection point are monitored in real time. When there is no energy storage fault and voltage transient, and when f is not within the frequency dead zone, Δp is calculated to control the energy storage output.

[0106]

[0107] in, △ P represents the primary frequency modulation amount, f H 、f L They represent the upper and lower dead zones of primary frequency modulation, respectively. N represents the rated frequency of the photovoltaic power station, f represents the real-time monitoring frequency, δ 上 , δ 下 They represent the up-regulation rate and down-regulation rate of the fast frequency modulation response respectively.

[0108] Among them, the frequency modulation dead zone refers to the standard boundary ±SOC d In the process, the energy storage does not work to prevent the energy storage action from switching back and forth at the boundary.

[0109] Among them, the real-time power of energy storage, frequency of the total grid-connected point, power, voltage and other data can be obtained from the electric meter, frequency measuring device or other measuring device.

[0110] In this embodiment, the primary frequency modulation amount is determined by the third formula, and the energy storage is adjusted to perform corresponding charging and discharging operations, thereby reserving a larger adjustment space for the energy storage, achieving refined control of the energy storage, and facilitating improved support capabilities of the energy storage for the primary frequency modulation response.

[0111] Optionally, the primary frequency modulation control method further includes: optimizing the historical probability distribution by self-learning.

[0112] Specifically, in this embodiment, self-learning is used to optimize the historical probability distribution, which does not require the unlabeled data and the labeled data to have the same distribution; Figure 4In the system shown, the self-learning process generally includes: (1) setting the structure of the neural network; (2) generating unlabeled sample sets and labeled sample sets (training data sets and test data sets); (3) using sparse autoencoders to extract features from the labeled training sample sets and test sample sets; (4) using the training sample sets to train the softmax regression model; and (5) classifying the test data sets.

[0113] In this embodiment, optimizing the historical probability distribution through self-learning is beneficial to improving the accuracy of the upper and lower boundaries, thereby facilitating improving the support capability of energy storage for primary frequency modulation response.

[0114] Optionally, the primary frequency modulation control method further includes: adjusting the historical probability distribution according to the season.

[0115] Specifically, in this embodiment, when calculating the historical probability distribution of frequency modulation times, the frequency modulation frequency distribution in different seasons is counted, and a probability analysis is performed on this frequency distribution. Based on P1, P2, and P3, the SOC level adapted to the current season is automatically calculated and output. Considering seasonal variations and national electricity consumption, the statistical data may produce different probabilities corresponding to E and T, affecting the SOCi and SOCi' results, and ultimately affecting the SOC level determination, resulting in inconsistent charging and discharging adjustments of the energy storage system with actual conditions.

[0116] Among them, in addition to seasonal factors, statistical analysis can also be conducted on factors such as weather.

[0117] In this embodiment, adjusting the historical probability distribution according to the season is beneficial to improving the accuracy of the upper and lower boundaries, thereby improving the support capability of energy storage for primary frequency regulation response.

[0118] Another embodiment of the present invention provides a primary frequency modulation control system, comprising a computer-readable storage medium storing a computer program and a processor. When the computer program is read and executed by the processor, the primary frequency modulation control method described above is implemented.

[0119] Combine Figure 4 As shown, the control system of primary frequency modulation includes a data acquisition system, a data cleaning system, a classification manager, a statistical analysis system, a parameter preset system, a calculation processing system and an output system.

[0120] Although the present invention is disclosed as above, the scope of protection disclosed by the present invention is not limited thereto. Those skilled in the art may make various changes and modifications without departing from the spirit and scope of the present invention, and these changes and modifications will fall within the scope of protection of the present invention.

Claims

1. A control method for primary frequency modulation, characterized in that: include: Obtaining a historical probability distribution of a frequency modulation time, and determining a corresponding frequency modulation time according to a preset probability and the historical probability distribution; Obtaining an expected number of primary frequency modulations and a rated capacity of energy storage, and determining an upper limit and a lower limit of a primary frequency modulation support capability level according to the expected number of primary frequency modulations, the rated capacity of energy storage, and the primary frequency modulation time; Obtaining a current SOC, comparing the SOC with the upper limit and the lower limit, and controlling energy storage charging and discharging according to the comparison results; The determining of a corresponding frequency modulation time according to a preset probability and the historical probability distribution includes: Determine the i-th frequency modulation time Ti corresponding to the i-th preset probability Pi according to the historical probability distribution, where i=1, 2, ..., n, n≥3, P1<P2<...<Pi, T1<T2<...<Ti; The determining of the upper and lower limits of the primary frequency regulation support capability level according to the expected number of primary frequency regulation times, the energy storage rated capacity, and the primary frequency regulation time includes: The SOC corresponding to the lower boundary is determined according to a first formula, wherein the first formula includes: Among them, SOCi represents the SOC corresponding to the lower boundary of level i, SOC1<SOC2<SOC3, SOC L represents the lower boundary protection value of energy storage, E represents the expected number of frequency modulation times, T i represents the frequency regulation time, Pn represents the rated capacity of the photovoltaic power station, 10%*Pn represents the maximum frequency regulation output, and C represents the rated capacity of the energy storage.

2. The primary frequency modulation control method according to claim 1, characterized in that: The determining of the upper and lower limits of the primary frequency regulation support capability level according to the expected number of primary frequency regulation times, the energy storage rated capacity, and the primary frequency regulation time further includes: The SOC corresponding to the upper limit is determined according to a second formula, wherein the second formula includes: Among them, SOCi ， Respectively represent the SOC corresponding to the upper boundary of level i, SOC3 ， <SOC2 ， <SOC1 ， , SOC H Indicates the upper boundary protection value of energy storage.

3. The primary frequency modulation control method according to claim 2, characterized in that: Comparing the SOC with the upper limit and the lower limit, and controlling the charging and discharging of energy storage according to the comparison results includes: When the SOC is less than SOC3, controlling energy storage charging; When the SOC is greater than SOC3 and less than SOC3 ， When , the control energy storage does not act; When the SOC is greater than SOC3 ， When the energy storage is discharged, the discharge is controlled.

4. The primary frequency modulation control method according to claim 3, characterized in that: When the SOC is less than SOC3, controlling energy storage charging includes: When the SOC satisfies 0<SOC<SOC1, controlling the energy storage to charge until the SOC reaches SOC1, SOC2 or SOC3; When the SOC satisfies SOC1<SOC<SOC2, controlling the energy storage to charge until the SOC reaches SOC2 or SOC3; When the SOC satisfies SOC2<SOC<SOC3, controlling the energy storage to charge until the SOC reaches SOC3 or not taking any action; When the SOC is greater than SOC3 ， When the energy storage discharge is controlled, the following steps are performed: When the SOC meets SOC3 ， <SOC<SOC2 ， When the energy storage is controlled to discharge until the SOC reaches SOC3 ， or no action; When the SOC meets SOC2 ， <SOC<SOC1 ， When the energy storage is controlled to discharge until the SOC reaches SOC2 ， or SOC3 ， ; When the SOC meets SOC1 ， When SOC is less than 1, the energy storage is controlled to discharge until the SOC reaches SOC1. ， 、SOC2 ， or SOC3 ， .

5. The primary frequency modulation control method according to claim 4, characterized in that: Also includes: According to the set failure rate of the primary frequency modulation, the energy storage is controlled to charge until the SOC reaches the SOC corresponding to different lower boundaries, or the energy storage is controlled to discharge until the SOC reaches the SOC corresponding to different upper boundaries.

6. The primary frequency modulation control method according to claim 4, characterized in that: Also includes: When a primary frequency modulation occurs, the primary frequency modulation amount is determined according to a third formula, wherein the third formula includes: in, △ P represents the primary frequency modulation amount, f H 、f L They represent the upper and lower dead zones of primary frequency modulation, respectively. N represents the rated frequency of the photovoltaic power station, f represents the real-time monitoring frequency, δ 上 , δ 下 They represent the up-regulation rate and down-regulation rate of the fast frequency modulation response respectively.

7. The primary frequency modulation control method according to any one of claims 1 to 6, characterized in that: Also includes: Self-learning is used to optimize the historical probability distribution.

8. The primary frequency modulation control method according to any one of claims 1 to 6, characterized in that: Also includes: The historical probability distribution is adjusted according to season.

9. A primary frequency modulation control system, characterized in that: The invention comprises a computer-readable storage medium storing a computer program and a processor, wherein when the computer program is read and executed by the processor, the method for controlling primary frequency modulation according to any one of claims 1 to 8 is implemented.

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