A collaborative autonomous method and device based on a power supply area source network load storage

Abstract

This invention relates to the field of low-voltage intelligent power distribution technology, and provides a collaborative autonomous method and device based on distribution transformer area source-grid-load-storage. The method includes setting values ​​of L1 and L2, where L1 is a high threshold for distribution transformer load rate and L2 is a low threshold for distribution transformer load rate; then, based on the numerical relationship between distribution transformer load rate and L1 and L2, entering a safe operation mode, a photovoltaic consumption mode, and an economic operation mode; executing corresponding charging and discharging processes in different modes, and coordinating and controlling the output and load direction of distributed generation and energy storage through edge computing, so as to ensure the safe and reliable operation of the distribution transformer area, while minimizing the number of adjustments to energy storage and extending the service life of energy storage.

Description

Technical Field

[0001] The present invention relates to the technical field of low-voltage intelligent power distribution, and particularly to a collaborative autonomous method and device based on source-network-load-storage in a transformer area. Background Art

[0002] Under the background of the new power system, a large number of distributed power sources and diversified flexible loads will be connected to the distribution network, such as photovoltaic power generation, user-side energy storage, new energy vehicles, microgrids, flexible loads, etc. The form and operation mode of the low-voltage distribution network are increasingly affected. Through the collaborative optimization regulation of light, storage, charging and load in the transformer area, flexible consumption and intelligent operation control of distributed power sources, interactive control of source-network-load-storage can be realized, load can be balanced by peak shifting and valley filling, the level of networking, digitization and intelligence of the distribution network can be promoted, the bearing capacity of the distribution network can be improved, and the construction of the new power system can be promoted. Summary of the Invention

[0003] The intelligent fusion terminal in the transformer area is installed on the low-voltage side of the transformer in the transformer area. The fusion terminal communicates with source-network-load-storage devices such as photovoltaic power generation, energy storage, charging piles, and air conditioners in the transformer area through communication methods such as RS485 / HPLC / LORA. On the one hand, it sends data to the main station of distribution automation to realize the visibility and measurability of source-network-load-storage devices. On the other hand, the fusion terminal can respond to the regulation instructions of the distribution automation system to realize the adjustability and controllability of source-network-load-storage devices. Through edge computing, the output and load direction of distributed power generation and energy storage are coordinated and controlled to make the distribution transformer area operate safely and reliably.

[0004] The present invention provides a collaborative autonomous method based on source-network-load-storage in a transformer area, including the following steps:

[0005] S1: Set the values of L1 and L2, where L1 is the high threshold of the load rate of the distribution transformer and L2 is the low threshold of the load rate of the distribution transformer;

[0006] S2: When the load rate of the distribution transformer >= L1, enter the safe operation mode,

[0007] When the load rate of the distribution transformer <= L2, enter the photovoltaic consumption mode,

[0008] When the load rate of the distribution transformer > L2 and the load rate of the distribution transformer < L1, enter the economic operation mode;

[0009] S3: After entering the safe operation mode, check and confirm that the photovoltaic enters the MPPT full power generation state. If the photovoltaic is operating at a limited power,解除限制 (the specific meaning of this phrase needs to be determined according to the context, it may be "remove the limit"), at this time, if there is still a power deficit, energy storage is discharged according to the power deficit, and at the same time, it is ensured that the energy storage discharge power is within the rated range. When the energy storage SOC drops to the low limit value of the energy storage SOC, the discharge stops.

[0010] If there is still a power deficit after energy storage discharges, limit the power of controllable loads in the distribution area. If there is still a power deficit after power limiting, cut off the controllable loads;

[0011] S4: When entering the photovoltaic accommodation mode, first set the peak start time point and peak end time point of the evening peak. According to the predicted photovoltaic power generation curve of the day, obtain the predicted photovoltaic start power generation time point, the predicted photovoltaic end power generation time point, and the predicted total photovoltaic power generation W power generation of the day.

[0012] When the time range is from 0:00 to the predicted photovoltaic start power generation time point, the energy storage discharges at a constant power until the end of this time period or the SOC of the energy storage drops to the low limit value. The discharge power = energy storage rated capacity * (SOC - energy storage SOC low limit value) / ((photovoltaic start power generation time point - 0 o'clock) - 1 hour), and at the same time, the magnitude of the discharge power does not exceed the rated discharge power range of the energy storage.

[0013] When the time range is from the predicted photovoltaic start power generation time point to the predicted photovoltaic end power generation time point, charge the energy storage at a constant power. The calculation method of the charging power is as follows:

[0014] First calculate the energy storage capacity to be accommodated, where the energy storage capacity to be accommodated = energy storage rated capacity * (100% - SOC).

[0015] When the energy storage capacity to be accommodated > W power generation, the charging power = W power generation / (predicted photovoltaic end power generation time point - predicted photovoltaic start power generation time point), and at the same time, the magnitude of the charging power does not exceed the rated charging power range of the energy storage.

[0016] When the energy storage capacity to be accommodated < W power generation, the energy storage only accommodates the period with the largest power generation load. Integrate the photovoltaic power generation data from the point with the largest photovoltaic power generation power in the predicted photovoltaic power generation curve of the day to both sides to obtain the power generation amount until the power generation amount > the energy storage capacity to be accommodated, and obtain the energy storage charging period. Only charge the energy storage during this time period. The charging power = energy storage capacity to be accommodated / total duration of the energy storage charging period, and at the same time, the magnitude of the charging power does not exceed the rated charging power range of the energy storage.

[0017] When the time range is from the peak start time point to the peak end time point and the distribution transformer load rate is higher than the peak allowable discharge threshold, the energy storage starts to discharge at a constant power until the end of the time period or the SOC of the energy storage drops to the low limit value. The discharge power = energy storage rated capacity * (SOC - energy storage SOC low limit value) / (peak end time point - peak start time point), and at the same time, the magnitude of the discharge power does not exceed the rated discharge power range of the energy storage;

[0018] S5: When entering the economic operation mode, set the peak period, valley period, and normal period.

[0019] During off-peak hours, the energy storage is charged at a constant power until it is fully charged or the time period ends. The charging power is calculated as follows: Charging power = Rated energy storage capacity * (100% - SOC) / Total duration of the off-peak period. The charging power must not exceed the rated charging power range of the energy storage.

[0020] During peak hours, the energy storage discharges at a constant power until the energy storage SOC drops to the lower limit or the time period ends. The discharge power = rated energy storage capacity * (SOC - lower limit of energy storage SOC) / total duration of the peak period. Simultaneously, the discharge power does not exceed the rated discharge power range of the energy storage.

[0021] During normal periods, power quality can be optimized by adjusting energy storage or photovoltaic equipment.

[0022] Furthermore,

[0023] S3 also includes locking the safe operation mode for a preset time after entering the safe operation mode, and switching to the corresponding operation mode according to the load rate after the preset time ends;

[0024] S4 also includes locking the photovoltaic consumption mode for a preset time after entering the photovoltaic consumption mode, and switching to the corresponding operating mode according to the load rate after the preset time ends.

[0025] S5 also includes a feature that after entering the economic operation mode, the economic operation mode is locked for a preset time. After the preset time ends, the mode is switched to the corresponding operation mode based on the load rate.

[0026] Furthermore,

[0027] S3 also includes: if the transformer load rate drops to L1*k, then stop the energy storage discharge, where k is a safety factor set value, which is greater than 0 and less than 1.

[0028] Furthermore,

[0029] S4 also includes a method for obtaining the photovoltaic power generation forecast curve for the day, the specific method being:

[0030] For each point in time on the day, Ppredicted = Pyesterday * 0.5 + Pday before yesterday * 0.3 + Ptwo days before * 0.2; where Ppredicted represents the predicted photovoltaic power generation for that point in time, Pyesterday represents the photovoltaic power generation for that point yesterday, Pday before yesterday represents the photovoltaic power generation for that point two days before, and Ptwo days before represents the photovoltaic power generation for that point two days before. After calculating for all points in time throughout the day, the predicted photovoltaic power generation for all points in time on the day is obtained, which is the photovoltaic power generation prediction curve for that day.

[0031] Furthermore,

[0032] S5 also includes specific power quality optimization content for adjusting reactive power deficiency and adjusting three-phase imbalance in the transformer area. The specific adjustment methods are as follows:

[0033] When there is reactive power deficiency and the value is greater than the action threshold, calculate the required reactive power = (rated power factor to be compensated - current power factor) * (current power - three-phase charge-discharge power of energy storage). If the required reactive power ≤ the maximum reactive power that the energy storage can increase, the energy storage releases reactive power with the required reactive power. If the required reactive power > the maximum reactive power that the energy storage can increase, then adjust the photovoltaic to release reactive power, and at the same time, the photovoltaic reactive power range does not exceed the rated range;

[0034] When there is three-phase imbalance and the value exceeds the action threshold, calculate the balanced active power = (phase A active power + phase B active power + phase C active power) / 3 according to the three-phase power balance method.

[0035] Then calculate the active power to be adjusted for each phase. The active power to be adjusted for phase A = phase A active power - balanced active power. Similarly, the active power to be adjusted for phase B and phase C can be obtained. For the active power to be adjusted for any one of phases A, B, and C, if the active power to be adjusted ≤ the maximum active power that the energy storage can adjust for a single phase, the energy storage supports with the required active power. If the active power to be adjusted > the maximum active power that the energy storage can adjust for a single phase, then adjust the active power of the corresponding phase of the photovoltaic, and at the same time, the photovoltaic active power range does not exceed the rated range.

[0036] The present invention also provides a collaborative autonomous device based on the source-network-load-storage in the transformer area, including the following modules:

[0037] Numerical setting module: used to set the values of L1 and L2, where L1 is the high threshold of the transformer load rate and L2 is the low threshold of the transformer load rate;

[0038] Judgment module: used to enter the safe operation mode when the transformer load rate ≥ L1.

[0039] Enter the photovoltaic accommodation mode when the transformer load rate ≤ L2.

[0040] Enter the economic operation mode when the transformer load rate > L2 and the transformer load rate < L1;

[0041] Safe operation module: used to check and confirm that the photovoltaic enters the MPPT full power generation state after entering the safe operation mode. If the photovoltaic is operating at a limited power,解除 the limit. At this time, if there is still a power shortage, the energy storage discharges according to the power shortage, and at the same time, ensure that the energy storage discharge power is within the rated range. When the energy storage SOC drops to the low limit value of the energy storage SOC, stop discharging.

[0042] If there is still a power deficit after energy storage discharges, the power of controllable loads in the distribution area is limited. If there is still a power deficit after power limitation, the controllable loads are disconnected;

[0043] Photovoltaic accommodation module: When entering the photovoltaic accommodation mode, first set the peak start time point and peak end time point of the evening peak. According to the predicted photovoltaic power generation curve of the day, obtain the predicted photovoltaic start power generation time point, predicted photovoltaic end power generation time point, and predicted total photovoltaic power generation W_power of the day.

[0044] When the time range is from 0:00 to the predicted photovoltaic start power generation time point, the energy storage discharges at a constant power until the end of this time period or the SOC of the energy storage drops to the low limit value. The discharge power = rated capacity of the energy storage * (SOC - low limit value of the energy storage SOC) / ((photovoltaic start power generation time point - 0 o'clock) - 1 hour), and at the same time, the magnitude of the discharge power does not exceed the rated discharge power range of the energy storage.

[0045] When the time range is from the predicted photovoltaic start power generation time point to the predicted photovoltaic end power generation time point, charge the energy storage at a constant power. The calculation method of the charging power is as follows:

[0046] First, calculate the energy storage accommodation capacity, where the energy storage accommodation capacity = rated capacity of the energy storage * (100% - SOC).

[0047] When the energy storage accommodation capacity > W_power, the charging power = W_power / (predicted photovoltaic end power generation time point - predicted photovoltaic start power generation time point), and at the same time, the magnitude of the charging power does not exceed the rated charging power range of the energy storage.

[0048] When the energy storage accommodation capacity < W_power, the energy storage only accommodates the period with the largest power generation load. Integrate the photovoltaic power generation data from the point with the largest photovoltaic power generation power in the predicted photovoltaic power generation curve of the day to both sides to obtain the generated electricity until the generated electricity > the energy storage accommodation capacity, and obtain the energy storage charging period. Only charge the energy storage during this time period. The charging power = energy storage accommodation capacity / total duration of the energy storage charging period, and at the same time, the magnitude of the charging power does not exceed the rated charging power range of the energy storage.

[0049] When the time range is from the peak start time point to the peak end time point and the load rate of the distribution transformer is higher than the peak allowable discharge threshold, the energy storage starts to discharge at a constant power until the end of the time period or the SOC of the energy storage drops to the low limit value. The discharge power = rated capacity of the energy storage * (SOC - low limit value of the energy storage SOC) / (peak end time point - peak start time point), and at the same time, the magnitude of the discharge power does not exceed the rated discharge power range of the energy storage;

[0050] Economic operation module: When entering the economic operation mode, set the peak period, valley period, and normal period.

[0051] During off-peak hours, the energy storage is charged at a constant power until it is fully charged or the time period ends. The charging power is calculated as follows: Charging power = Rated energy storage capacity * (100% - SOC) / Total duration of the off-peak period. The charging power must not exceed the rated charging power range of the energy storage.

[0052] During peak hours, the energy storage discharges at a constant power until the energy storage SOC drops to the lower limit or the time period ends. The discharge power = rated energy storage capacity * (SOC - lower limit of energy storage SOC) / total duration of the peak period. Simultaneously, the discharge power does not exceed the rated discharge power range of the energy storage.

[0053] During normal periods, power quality can be optimized by adjusting energy storage or photovoltaic equipment.

[0054] Furthermore,

[0055] The safe operation module also includes locking the safe operation mode for a preset time after entering the safe operation mode, and switching to the corresponding operation mode according to the load rate after the preset time ends.

[0056] The photovoltaic grid connection module also includes a function that, after entering the photovoltaic grid connection mode, locks the photovoltaic grid connection mode for a preset time, and after the preset time ends, switches to the corresponding operating mode according to the load rate.

[0057] The economic operation module also includes locking the economic operation mode for a preset time after entering the economic operation mode, and switching to the corresponding operation mode according to the load rate after the preset time ends.

[0058] Furthermore,

[0059] The safe operation module also includes: if the distribution transformer load rate drops to L1*k, then stop the energy storage discharge, where k is a safety factor fixed value, which takes a value greater than 0 and less than 1.

[0060] Furthermore,

[0061] The photovoltaic (PV) grid integration module also includes a method for obtaining the PV power generation forecast curve for the day, specifically as follows:

[0062] For each point in time on the day, Ppredicted = Pyesterday * 0.5 + Pday before yesterday * 0.3 + Ptwo days before * 0.2; where Ppredicted represents the predicted photovoltaic power generation for that point in time, Pyesterday represents the photovoltaic power generation for that point yesterday, Pday before yesterday represents the photovoltaic power generation for that point two days before, and Ptwo days before represents the photovoltaic power generation for that point two days before. After calculating for all points in time throughout the day, the predicted photovoltaic power generation for all points in time on the day is obtained, which is the photovoltaic power generation prediction curve for that day.

[0063] Furthermore,

[0064] The economic operation module also includes specific power quality optimization measures, such as adjusting reactive power deficit and adjusting three-phase imbalance in transformer substations. The specific adjustment methods are as follows:

[0065] When reactive power is insufficient and the value is greater than the action threshold, the required reactive power is calculated as follows: (power factor to be compensated set value - current power factor) * (current power - energy storage three-phase charging and discharging power). If the required reactive power is less than or equal to the maximum reactive power that energy storage can increase, the energy storage releases reactive power at the required reactive power. If the required reactive power is greater than the maximum reactive power that energy storage can increase, the photovoltaic system releases reactive power, while the photovoltaic reactive power range does not exceed the rated range.

[0066] When the three phases are unbalanced and the value exceeds the action threshold, the balanced active power is calculated according to the three-phase power balance method: Balanced active power = (Phase A active power + Phase B active power + Phase C active power) / 3.

[0067] Then calculate the active power to be adjusted for each phase. The active power to be adjusted for phase A = active power of phase A - balanced active power. Similarly, the active power to be adjusted for phases B and C can be obtained. For the active power to be adjusted for any one of phases A, B, and C, if the active power to be adjusted is less than or equal to the maximum active power that can be adjusted for a single phase of energy storage, the energy storage is supported by the active power required. If the active power to be adjusted is greater than the maximum active power that can be adjusted for a single phase of energy storage, the active power of the corresponding photovoltaic phase is adjusted, while the active power range of the photovoltaic does not exceed the rated range.

[0068] The beneficial effects of this invention are:

[0069] 1. When designing the charging and discharging process, minimize the number of energy storage adjustments to extend the energy storage lifespan. For example, consuming the stored energy one hour before photovoltaic power generation can reduce the number of energy storage discharge adjustments, ensure balanced discharge, and extend the energy storage lifespan; charging at a constant power can also reduce the number of energy storage adjustments and extend the energy storage lifespan.

[0070] 2. In the photovoltaic consumption mode, when the total photovoltaic power generation is sufficient to fully charge the energy storage, charging is only carried out during the period of maximum power generation. At this time, the photovoltaic power generation is large and there is a backflow phenomenon in the distribution area. Storing energy during the peak photovoltaic power generation can smooth out the load of photovoltaic power generation. Attached Figure Description

[0071] Figure 1 Flowchart of coordinated control of power generation, grid, load and storage in the power grid area;

[0072] Figure 2 Flowchart for safe operation mode;

[0073] Figure 3 A flowchart of photovoltaic power grid integration mode;

[0074] Figure 4 This is a flowchart of the economic operation model. Detailed Implementation

[0075] The data related to the power grid-load-storage equipment in the distribution area mainly includes:

[0076] 1) Data acquisition and control from end-side source-load storage equipment:

[0077]

[0078]

[0079] 2) Edge computing side data:

[0080]

[0081] 3) Main station side data

[0082]

[0083] A collaborative self-governance approach for power generation, grid, load, and storage in power distribution areas:

[0084] The autonomous management method for power generation, grid, load, and energy storage in power distribution areas is divided into three modes based on transformer load conditions: safe operation mode, photovoltaic (PV) consumption mode, and economic operation mode. The priority of the three modes is: safe operation mode > PV consumption mode > economic operation mode. The master station can also force the power distribution area to operate in a specified mode by issuing commands.

[0085] Safe operation mode: When the load rate of the distribution transformer exceeds the load rate setting value L1, the transformer is in a state of severe overload and enters the safe operation mode.

[0086] Photovoltaic consumption mode: When the load rate of the distribution transformer is lower than the preset load rate setting value L2, the photovoltaic system experiences backfeeding and enters the photovoltaic consumption mode.

[0087] Economic operation mode: When the transformer load rate is between L1 and L2, the transformer operates in economic operation mode.

[0088] Execution process:

[0089] 1) During startup, the system parses the configuration information of the power grid, load, and storage equipment and measurement points in the distribution area, mainly including the type information of the power grid, load, and storage equipment, communication configuration, etc.

[0090] 2) After entering the main cycle, based on the equipment and the reference measurement point configuration of the transformer area, the real-time data of the source-grid-load-storage equipment and the load rate data of the transformer area are updated in real time.

[0091] 3) If the transformer load rate is greater than or equal to the L1 set value, enter the safe operation mode and execute the safe operation mode logic;

[0092] 4) If the distribution transformer load rate <= the L2 fixed value, enter the photovoltaic accommodation mode and execute the photovoltaic accommodation mode logic;

[0093] 5) If the distribution transformer load rate > the L2 fixed value and the distribution transformer load rate < the L1 fixed value, enter the economic operation mode and execute the economic operation logic. Specifically, as Figure 1 shown.

[0094] Safe operation mode process (as Figure 2 shown):

[0095] Execution process:

[0096] When entering the safe operation mode, check and confirm that the photovoltaic enters the MPPT full power generation state. If the power is limited due to other reasons, the limit is lifted;

[0097] If the distribution area is still severely overloaded, calculate the power deficit for energy storage discharge. The discharge power does not exceed the rated discharge power of the energy storage. If the energy storage discharge SOC drops to 20% (20% is the low limit value of the energy storage SOC and can be set according to the situation), stop the energy storage discharge support;

[0098] If the distribution area is still severely overloaded, calculate the controllable load for power limitation. If it still cannot be satisfied, cut off the controllable load, where the controllable load mainly includes charging piles and adjustable air conditioner loads;

[0099] If the distribution transformer load rate drops to L1*k (k is a fixed value of the safety factor, with a value greater than 0 and less than 1, for example, taking 0.9), stop the energy storage discharge support;

[0100] After executing the scheduling delay, end the call for the current safe operation mode operation. Specifically, it means that after entering the safe operation mode, within the preset time, lock the safe operation mode. After the preset time ends, switch to the corresponding operation mode according to the size of the load rate.

[0101] Photovoltaic accommodation mode process (as Figure 3 shown):

[0102] Execution process:

[0103] When entering the photovoltaic accommodation mode, if it is in the early morning period, for example, the early morning period of a certain day is 00:00 - 06:00 (where 0:00 is a constant, 06:00 is the time point when the photovoltaic starts generating electricity, and can be obtained through data such as the historical power generation situation of the photovoltaic), after entering this period, the energy storage starts to discharge;

[0104] The specific calculation method of the discharge process is as follows:

[0105] Discharge time = (the time point when the photovoltaic starts generating electricity - 0 o'clock) - 1 hour;

[0106] Discharge power = (SOC-20%) * rated energy storage capacity / discharge time, where 20% is the lower limit of energy storage SOC, which can be set according to the situation;

[0107] If the calculated discharge power is greater than the maximum discharge power of the energy storage, then the energy storage will discharge at the maximum discharge power; otherwise, it will discharge at the calculated discharge power. During the discharge process, if the time period expires or the State of Charge (SOC) is less than or equal to 20%, the energy storage will stop discharging. 20% is the minimum SOC value for the energy storage, which can be set as needed.

[0108] One hour before photovoltaic power generation, the energy storage capacity is reduced to the minimum SOC value, which can reduce the number of energy storage discharge regulation times, balance discharge, and extend the service life of energy storage.

[0109] If it is during the photovoltaic power generation period, calculate the energy storage equalization charging power based on the photovoltaic power generation forecast data, and fully charge the energy storage.

[0110] The charging process calculation method is as follows:

[0111] First, the photovoltaic power generation forecast curve for the day is obtained based on historical photovoltaic power generation data and weather forecasts. For example, it can be calculated like this:

[0112] The terminal stores the historical 3-day photovoltaic power generation active power curve, and then calculates the predicted photovoltaic power generation curve according to the weights: P_predicted = P_yesterday * 0.5 + P_daybefore * 0.3 + P_two days ago * 0.2; where P_predicted represents the predicted photovoltaic power generation value for a certain time point on that day, P_yesterday represents the photovoltaic power generation value of that time point yesterday, P_daybefore * 0.3 represents the photovoltaic power generation value of that time point two days ago, and P_two days ago * 0.2 represents the photovoltaic power generation value of that time point two days ago. The calculation is performed for all time points throughout the day to obtain the predicted power generation value for all time points on that day, which is the photovoltaic power generation prediction curve for that day.

[0113] Then, based on the photovoltaic power generation forecast curve, the total photovoltaic power generation capacity W and the power generation time T (expected photovoltaic power generation end time - expected photovoltaic power generation start time) are calculated for the day.

[0114] When the photovoltaic power generation period begins, the energy storage capacity to be consumed is calculated based on the current SOC of the energy storage and the predicted photovoltaic power generation capacity.

[0115] Energy storage capacity to be consumed = Rated energy storage capacity * (100% - SOC);

[0116] When the energy storage capacity to be consumed is greater than W of power generation, the charging power = W of power generation / T of power generation. If the charging power is less than the minimum charging power of energy storage, then the charging power = the minimum charging power of energy storage.

[0117] When the energy storage capacity to be absorbed < W power generation, the energy storage only absorbs the period with the largest power generation load. Integrate the power generation data from the maximum point of the photovoltaic power generation prediction curve to both sides to calculate the power generation amount until the power generation amount > the energy storage capacity to be absorbed, obtaining the energy storage charging period. The charging power = the energy storage capacity to be absorbed / the total duration of the energy storage charging period. During the peak of photovoltaic power generation, the photovoltaic power generation is relatively high, and there is a phenomenon of reverse power transmission in the distribution area. Energy storage during the period with the largest photovoltaic power generation can smooth the load of photovoltaic power generation.

[0118] The energy storage is not allowed to be regulated frequently. To reduce the number of energy storage regulations, the above process adopts an equalized charging method (constant power charging), which can extend the service life of the energy storage.

[0119] If it is during the peak evening electricity consumption period and peak - time energy storage discharge is allowed, calculate the equalized discharge power at the peak electricity consumption moment according to the current SOC of the energy storage, and perform equalized discharge under the condition that the SOC of the energy storage is 20% and above. Here, 20% is the low - limit value of the SOC of the energy storage, which can be set according to the situation;

[0120] The calculation method of the discharge process is as follows:

[0121] The peak evening electricity consumption period is preset according to the load characteristics of the region and season. According to the set peak start time point T1 (e.g., 19:00) and peak end time point T2 (e.g., 21:00);

[0122] Discharge time = (T2 - T1) hours,

[0123] Discharge power = (SOC - 20%) * rated energy storage capacity / discharge time. If the calculated discharge power > the maximum discharge power of the energy storage, discharge at the maximum discharge power of the energy storage; otherwise, discharge at the calculated discharge power. During the discharge process, if the time period ends or SOC ≤ 20%, the energy storage stops discharging. Here, 20% is the low - limit value of the SOC of the energy storage, which can be set according to the situation.

[0124] Whether peak - time energy storage discharge is allowed is determined by the load rate of the distribution transformer. If the load rate of the distribution transformer is too low (lower than the peak - allowable discharge threshold), energy storage discharge may cause reverse power transmission in the distribution area, and at this time, peak - time energy storage discharge is not allowed.

[0125] After executing the scheduling delay, end the call of the current photovoltaic absorption mode operation. Specifically, it means that after entering the photovoltaic absorption mode, within the preset time, lock the photovoltaic absorption mode. After the preset time ends, switch to the corresponding operation mode according to the size of the load rate.

[0126] The process of the economic operation mode (as Figure 4 shown):

[0127] Execution process:

[0128] Peak, valley and normal periods are preset according to regional and seasonal load characteristics, and 24-hour time periods can be distributed through the main station on a timed basis.

[0129] When entering the economic operation mode, if it is during the off-peak period, the energy storage calculates the equalization charging power based on the energy storage SOC and the total length of the charging period, and performs energy storage equalization charging.

[0130] The charging process calculation method is as follows:

[0131] Energy storage capacity awaiting charging = rated energy storage capacity * (100% - SOC);

[0132] Total charging time = Total off-peak time;

[0133] Charging power = Energy storage capacity to be charged / Total charging time. If the calculated charging power is greater than the maximum charging power of the energy storage, the maximum charging power will be used for charging; otherwise, the calculated charging power will be used. During the charging process, if the time period ends or the SOC is greater than or equal to 100%, the energy storage will stop charging.

[0134] If it is during peak hours, the energy storage calculates the equalization discharge power based on the energy storage SOC and the total length of the peak electricity consumption period, and performs energy storage equalization discharge.

[0135] The calculation method for the discharge process is as follows:

[0136] Energy storage standby discharge capacity = rated energy storage capacity * (SOC - 20%), where 20% is the lower limit of energy storage SOC, which can be set according to the situation;

[0137] Total discharge period duration = Total peak period duration;

[0138] Discharge power = Energy storage capacity to be discharged / Total discharge time. If the calculated discharge power > the maximum discharge power of the energy storage, charge at the maximum discharge power of the energy storage; otherwise, discharge at the calculated discharge power. During the discharge process, if the time period ends or SOC ≤ 20%, the energy storage stops charging.

[0139] During normal periods, based on the power quality of the distribution area, branches, and photovoltaic access points, if a reactive power deficiency occurs, the reactive power deficit is calculated, and the reactive power compensation of distributed energy is adjusted; if a three-phase imbalance occurs in the distribution area, the active power compensation of distributed energy is calculated according to the three-phase current balance method, and the active power of each phase of distributed energy is allocated.

[0140] The optimization calculation method for reactive power compensation is as follows:

[0141] When reactive power is insufficient and the value is greater than the action threshold, the required reactive power is calculated as follows: (power factor to be compensated set value - current power factor) * (current power - energy storage three-phase charging and discharging power). If the required reactive power is less than or equal to the maximum reactive power that energy storage can increase, the energy storage releases reactive power at the required reactive power. If the required reactive power is greater than the maximum reactive power that energy storage can increase, the photovoltaic system releases reactive power, while the photovoltaic reactive power range does not exceed the rated range.

[0142] The optimization calculation method for three-phase imbalance is as follows:

[0143] When the three phases are unbalanced and the value exceeds the action threshold, the balanced active power is calculated according to the three-phase power balance method: Balanced active power = (Phase A active power + Phase B active power + Phase C active power) / 3.

[0144] Then calculate the active power to be adjusted for each phase. The active power to be adjusted for phase A = active power of phase A - balanced active power. Similarly, the active power to be adjusted for phases B and C can be obtained. For the active power to be adjusted for any one of phases A, B, and C, if the active power to be adjusted is less than or equal to the maximum active power that can be adjusted for a single phase of energy storage, the energy storage is supported by the active power required. If the active power to be adjusted is greater than the maximum active power that can be adjusted for a single phase of energy storage, the active power of the corresponding photovoltaic phase is adjusted, while the active power range of the photovoltaic does not exceed the rated range.

[0145] Power quality optimization is only performed during normal periods, at which time energy storage and photovoltaic power generation serve the purpose of power quality optimization.

[0146] After the scheduling delay, the current economic operation mode call ends. Specifically, after entering the economic operation mode, the economic operation mode is locked for a preset time. After the preset time ends, the system switches to the corresponding operation mode based on the load rate.

Claims

1. A collaborative autonomous method based on source-grid-load-storage in a transformer substation area, characterized in that... It includes the following steps: S1: Set the values of L1 and L2, where L1 is the high threshold of the distribution transformer load rate and L2 is the low threshold of the distribution transformer load rate; S2: When the distribution transformer load rate >= L1, enter the safe operation mode. When the distribution transformer load rate <= L2, enter the photovoltaic accommodation mode. When the distribution transformer load rate > L2 and the distribution transformer load rate < L1, enter the economic operation mode; S3: After entering the safe operation mode, check and confirm that the photovoltaic enters the MPPT full power generation state. If the photovoltaic is operating at a limited power,解除限制 (the text seems to be incomplete here, it might be "解除功率限制" or something similar), at this time, if there is still a power deficit, energy storage discharges according to the power deficit, while ensuring that the energy storage discharge power is within the rated range. When the energy storage SOC drops to the low limit value of the energy storage SOC, stop discharging. If there is still a power deficit after the energy storage discharges, limit the power of the controllable loads in the distribution area. If there is still a power deficit after the power is limited, cut off the controllable loads; S4: When entering the photovoltaic accommodation mode, first set the peak start time point and peak end time point of the late peak. According to the photovoltaic power generation prediction curve of the day, obtain the predicted photovoltaic start power generation time point, predicted photovoltaic end power generation time point, and predicted total photovoltaic power generation W_power of the day. When the time range is from 0:00 to the predicted photovoltaic start power generation time point, the energy storage discharges at a constant power until the end of this time period or the energy storage SOC drops to the low limit value. The discharge power = energy storage rated capacity * (SOC - energy storage SOC low limit value) / ((photovoltaic start power generation time point - 0:00) - 1 hour), and at the same time, the magnitude of the discharge power does not exceed the rated discharge power range of the energy storage. When the time range is from the predicted photovoltaic start power generation time point to the predicted photovoltaic end power generation time point, charge the energy storage at a constant power. The calculation method of the charging power is as follows: First, calculate the energy storage capacity to be accommodated, where the energy storage capacity to be accommodated = energy storage rated capacity * (100% - SOC). When the energy storage capacity to be accommodated > W_power, the charging power = W_power / (predicted photovoltaic end power generation time point - predicted photovoltaic start power generation time point), and at the same time, the magnitude of the charging power does not exceed the rated charging power range of the energy storage. When the energy storage capacity to be accommodated < W_power, the energy storage only accommodates the period with the largest power generation load. Integrate the photovoltaic power generation data from the point with the largest photovoltaic power generation power on the photovoltaic power generation prediction curve of the day to both sides to obtain the power generation amount until the power generation amount > the energy storage capacity to be accommodated, and obtain the energy storage charging period. Only charge the energy storage during this time period. The charging power = energy storage capacity to be accommodated / total duration of the energy storage charging period, and at the same time, the magnitude of the charging power does not exceed the rated charging power range of the energy storage. When the time range is from the peak start time point to the peak end time point and the distribution transformer load rate is higher than the peak allowable discharge threshold, the energy storage starts to discharge at a constant power until the end of the time period or the energy storage SOC drops to the low limit value. The discharge power = energy storage rated capacity * (SOC - energy storage SOC low limit value) / (peak end time point - peak start time point), and at the same time, the magnitude of the discharge power does not exceed the rated discharge power range of the energy storage; S5: When entering the economic operation mode, set the peak period, valley period, and normal period. During off-peak hours, the energy storage is charged at a constant power until it is fully charged or the time period ends. The charging power is calculated as follows: Charging power = Rated energy storage capacity * (100% - SOC) / Total duration of the off-peak period. The charging power must not exceed the rated charging power range of the energy storage. During peak hours, the energy storage discharges at a constant power until the energy storage SOC drops to the lower limit or the time period ends. The discharge power = rated energy storage capacity * (SOC - lower limit of energy storage SOC) / total duration of the peak period. Simultaneously, the discharge power does not exceed the rated discharge power range of the energy storage. During normal periods, power quality can be optimized by adjusting energy storage or photovoltaic equipment.

2. The collaborative autonomous method based on source-grid-load-storage in a transformer substation area according to claim 1, characterized in that: S3 also includes locking the safe operation mode for a preset time after entering the safe operation mode, and switching to the corresponding operation mode according to the load rate after the preset time ends; S4 also includes locking the photovoltaic consumption mode for a preset time after entering the photovoltaic consumption mode, and switching to the corresponding operating mode according to the load rate after the preset time ends. S5 also includes a feature that after entering the economic operation mode, the economic operation mode is locked for a preset time. After the preset time ends, the mode is switched to the corresponding operation mode based on the load rate.

3. The collaborative autonomous method based on source-grid-load-storage in a distribution area according to claim 1, characterized in that: S3 also includes: if the transformer load rate drops to L1*k, then stop the energy storage discharge, where k is a safety factor set value, which is greater than 0 and less than 1.

4. The collaborative autonomous method based on source-grid-load-storage in a distribution area according to claim 1, characterized in that: S4 also includes a method for obtaining the photovoltaic power generation forecast curve for the day, the specific method being: For each point in time on the day, Ppredicted = Pyesterday * 0.5 + Pday before yesterday * 0.3 + Ptwo days before * 0.2; where Ppredicted represents the predicted photovoltaic power generation for that point in time, Pyesterday represents the photovoltaic power generation for that point yesterday, Pday before yesterday represents the photovoltaic power generation for that point two days before, and Ptwo days before represents the photovoltaic power generation for that point two days before. After calculating for all points in time throughout the day, the predicted photovoltaic power generation for all points in time on the day is obtained, which is the photovoltaic power generation prediction curve for that day.

5. The collaborative autonomous method based on source-grid-load-storage in a distribution area according to claim 1, characterized in that: S5 also includes specific power quality optimization measures, such as adjusting reactive power deficit and adjusting three-phase imbalance in transformer substations. The specific adjustment methods are as follows: When reactive power is insufficient and the value is greater than the action threshold, the required reactive power is calculated as follows: (power factor to be compensated set value - current power factor) * (current power - energy storage three-phase charging and discharging power). If the required reactive power is less than or equal to the maximum reactive power that energy storage can increase, the energy storage releases reactive power at the required reactive power. If the required reactive power is greater than the maximum reactive power that energy storage can increase, the photovoltaic system releases reactive power, while the photovoltaic reactive power range does not exceed the rated range. When the three-phase is unbalanced and the value exceeds the action threshold, calculate the balanced active power according to the three-phase power balance method, where the balanced active power = (A-phase active power + B-phase active power + C-phase active power) / 3. Then calculate the active power to be adjusted for each phase. The active power to be adjusted for phase A = A-phase active power - balanced active power. Similarly, the active power to be adjusted for phases B and C can be obtained. For the active power to be adjusted for any one of phases A, B, and C, if the active power to be adjusted ≤ the maximum adjustable active power of the energy storage per phase, the energy storage supports with the required active power. If the active power to be adjusted > the maximum adjustable active power of the energy storage per phase, then adjust the active power of the corresponding phase of the photovoltaic, and at the same time, the range of the photovoltaic active power does not exceed the rated range.

6. A collaborative autonomous device based on source-grid-load-storage in a distribution area, characterized in that... It includes the following modules: Value setting module: used to set the values of L1 and L2, where L1 is the high threshold of the distribution transformer load rate and L2 is the low threshold of the distribution transformer load rate. Judgment module: used to enter the safe operation mode when the distribution transformer load rate >= L1. When the distribution transformer load rate <= L2, enter the photovoltaic accommodation mode. When the distribution transformer load rate > L2 and the distribution transformer load rate < L1, enter the economic operation mode. Safe operation module: used to check and confirm that the photovoltaic enters the MPPT full power generation state after entering the safe operation mode. If the photovoltaic is operating at a limited power,解除限制 (release the limit). At this time, if there is still a power shortage, discharge the energy storage according to the power shortage, and at the same time, ensure that the energy storage discharge power is within the rated range. When the energy storage SOC drops to the low limit value of the energy storage SOC, stop discharging. If there is still a power shortage after the energy storage discharges, limit the power of the controllable loads in the distribution area. If there is still a power shortage after the power is limited, cut off the controllable loads. Photovoltaic accommodation module: used to set the start time point and end time point of the peak when entering the photovoltaic accommodation mode. According to the predicted photovoltaic power generation curve of the day, obtain the predicted photovoltaic start power generation time point, the predicted photovoltaic end power generation time point, and the predicted total photovoltaic power generation W_power generation of the day. When the time range is from 0:00 to the predicted photovoltaic start power generation time point, the energy storage discharges at a constant power until the end of this time period or the energy storage SOC drops to the low limit value. The discharge power = energy storage rated capacity * (SOC - energy storage SOC low limit value) / ((photovoltaic start power generation time point - 0 o'clock) - 1 hour), and at the same time, the magnitude of the discharge power does not exceed the rated discharge power range of the energy storage. When the time range is from the predicted photovoltaic start power generation time point to the predicted photovoltaic end power generation time point, charge the energy storage at a constant power. The calculation method of the charging power is as follows: First, calculate the energy storage capacity to be accommodated, where the energy storage capacity to be accommodated = energy storage rated capacity * (100% - SOC). When the energy storage capacity to be accommodated > W_power generation, the charging power = W_power generation / (predicted photovoltaic end power generation time point - predicted photovoltaic start power generation time point), and at the same time, the magnitude of the charging power does not exceed the rated charging power range of the energy storage. When the energy storage capacity to be absorbed < W power generation, the energy storage only absorbs the time period with the largest power generation load. Integrate the power generation data from the maximum point of the photovoltaic power generation prediction curve of the day to both sides to calculate the power generation until the power generation > the energy storage capacity to be absorbed, and obtain the energy storage charging time period. Charge the energy storage only during this time period, and the charging power = the energy storage capacity to be absorbed / the total duration of the energy storage charging time period. At the same time, the magnitude of the charging power does not exceed the rated charging power range of the energy storage. When the time range is from the peak start time point to the peak end time point and the distribution transformer load rate is higher than the peak allowable discharge threshold, the energy storage starts to discharge at a constant power until the end of the time period or the energy storage SOC drops to the low limit value. The discharge power = the rated energy storage capacity * (SOC - the low limit value of the energy storage SOC) / (the peak end time point - the peak start time point). At the same time, the magnitude of the discharge power does not exceed the rated discharge power range of the energy storage. Economic operation module: used to set peak time periods, valley time periods, and normal time periods when entering the economic operation mode. When in the valley time period, charge the energy storage at a constant power until it is full or the time period ends. The calculation method of the charging power is: charging power = the rated energy storage capacity * (100% - SOC) / the total duration of the valley time period. At the same time, the magnitude of the charging power does not exceed the rated charging power range of the energy storage. When in the peak time period, the energy storage discharges at a constant power until the energy storage SOC drops to the low limit value or the time period ends. The discharge power = the rated energy storage capacity * (SOC - the low limit value of the energy storage SOC) / the total duration of the peak time period. At the same time, the magnitude of the discharge power does not exceed the rated discharge power range of the energy storage. When in the normal time period, optimize the power quality by adjusting the energy storage device or the photovoltaic device.

7. The coordinated autonomous device based on the source-network-load-storage in the distribution area according to claim 6, wherein: The safe operation module further includes locking the safe operation mode within a preset time after entering the safe operation mode. After the preset time ends, switch to the corresponding operation mode according to the magnitude of the load rate. The photovoltaic absorption module further includes locking the photovoltaic absorption mode within a preset time after entering the photovoltaic absorption mode. After the preset time ends, switch to the corresponding operation mode according to the magnitude of the load rate. The economic operation module further includes locking the economic operation mode within a preset time after entering the economic operation mode. After the preset time ends, switch to the corresponding operation mode according to the magnitude of the load rate.

8. The coordinated autonomous device based on the source-network-load-storage in the distribution area according to claim 6, wherein: The safe operation module further includes: if the distribution transformer load rate drops to L1 * k, stop the energy storage discharge, where k is a fixed safety factor value, and the value is greater than 0 and less than 1.

9. The coordinated autonomous device based on the source-network-load-storage in the distribution area according to claim 6, wherein: The photovoltaic absorption module further includes a method for obtaining the photovoltaic power generation prediction curve of the day. The specific method is: For each point in time on the day, Ppredicted = Pyesterday * 0.5 + Pday before yesterday * 0.3 + Ptwo days before * 0.2; where Ppredicted represents the predicted photovoltaic power generation for that point in time, Pyesterday represents the photovoltaic power generation for that point yesterday, Pday before yesterday represents the photovoltaic power generation for that point two days before, and Ptwo days before represents the photovoltaic power generation for that point two days before. After calculating for all points in time throughout the day, the predicted photovoltaic power generation for all points in time on the day is obtained, which is the photovoltaic power generation prediction curve for that day.

10. A collaborative autonomous device based on source-grid-load-storage in a distribution area according to claim 6, characterized in that: The economic operation module also includes specific power quality optimization measures, such as adjusting reactive power deficit and adjusting three-phase imbalance in transformer substations. The specific adjustment methods are as follows: When reactive power is insufficient and the value is greater than the action threshold, the required reactive power is calculated as follows: (power factor to be compensated set value - current power factor) * (current power - energy storage three-phase charging and discharging power). If the required reactive power is less than or equal to the maximum reactive power that energy storage can increase, the energy storage releases reactive power at the required reactive power. If the required reactive power is greater than the maximum reactive power that energy storage can increase, the photovoltaic system releases reactive power, while the photovoltaic reactive power range does not exceed the rated range. When the three phases are unbalanced and the value exceeds the action threshold, the balanced active power is calculated according to the three-phase power balance method: Balanced active power = (Phase A active power + Phase B active power + Phase C active power) / 3. Then calculate the active power to be adjusted for each phase. The active power to be adjusted for phase A = active power of phase A - balanced active power. Similarly, the active power to be adjusted for phases B and C can be obtained. For the active power to be adjusted for any one of phases A, B, and C, if the active power to be adjusted is less than or equal to the maximum active power that can be adjusted for a single phase of energy storage, the energy storage is supported by the active power required. If the active power to be adjusted is greater than the maximum active power that can be adjusted for a single phase of energy storage, the active power of the corresponding photovoltaic phase is adjusted, while the active power range of the photovoltaic does not exceed the rated range.

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