A photovoltaic power consumption optimization control method and system for a power distribution area

Abstract

This invention discloses a photovoltaic absorption optimization control method and system for a distribution transformer area, comprising the following steps: S1, the intelligent terminal of the distribution transformer area monitors the real-time frequency of the power frequency AC voltage at the grid connection point, and obtains the rate of change and acceleration of the real-time frequency at a sampling frequency not lower than a preset frequency value. This relates to the field of power system operation control technology. This application uses the intelligent terminal of the distribution transformer area to obtain the real-time frequency and acceleration d²f / dt² through high-frequency sampling, and generates a dynamic danger threshold ε by combining the load photovoltaic ratio K. The real-time frequency of the power frequency AC voltage is higher than the rated frequency, and the absolute value of the acceleration is greater than the dynamic danger threshold ε as the triggering condition for the coordinated absorption maintenance signal, thereby realizing the early identification of the frequency deterioration trend in the early stage of islanding; and realizing distributed coordinated load reduction.

Description

Technical Field

[0001] This invention relates to the field of power system operation and control technology, and in particular to a photovoltaic consumption optimization control method and system for a distribution substation. Background Technology

[0002] As the penetration rate of distributed photovoltaic (PV) power in distribution substations continues to increase, when a substation is momentarily disconnected from the main grid due to a fault in the upstream grid, an unprepared high-power island is formed. This results in unplanned microgrid island operation. At this time, the PV penetration rate in the substation is extremely high, and the load is momentarily far lower than the PV output, while the PV output is far higher than the load demand, causing the system frequency to spike. This creates a momentary, unprepared high-power island.

[0003] Currently, traditional frequency control relies on the photovoltaic inverter detecting overfrequency and then reducing load. However, the following technical problems still exist:

[0004] In an isolated situation, the system frequency can spike due to excess power. The conventional approach is for the photovoltaic inverter to perform overfrequency throttling. However, in the distribution area, numerous inverter air conditioners, water pumps, and industrial motors automatically reduce their input current to maintain constant power output when the frequency rises. This is equivalent to the load itself further unloading when the system already has excess power, exacerbating the rate and magnitude of the frequency rise. This can cause traditional overfrequency throttling measures to fail due to response lag, ultimately leading to system frequency collapse. Summary of the Invention

[0005] To address the technical problems existing in the background art, this invention proposes a photovoltaic power consumption optimization control method and system for distribution substations.

[0006] The present invention proposes a photovoltaic power consumption optimization control method for a distribution substation, comprising the following steps:

[0007] S1. The intelligent terminal in the distribution area monitors the real-time frequency of the power frequency AC voltage at the grid connection point of the distribution area, and obtains the rate of change and acceleration of change of the real-time frequency d²f / dt² at a sampling frequency not lower than the preset frequency value.

[0008] S2. The intelligent terminal in the distribution area obtains the real-time total load and total rated photovoltaic output of the distribution area, and obtains the load-to-photovoltaic ratio K.

[0009] S3. The intelligent terminal in the distribution area generates a dynamic danger threshold ε based on the load photovoltaic ratio K and the threshold generation mechanism.

[0010] S4. When the intelligent terminal of the distribution area determines that the real-time frequency is higher than the rated frequency and the absolute value of the change acceleration is greater than the dynamic danger threshold ε, the intelligent terminal of the distribution area generates a collaborative absorption maintenance signal and broadcasts the collaborative absorption maintenance signal to all photovoltaic inverters participating in collaborative control within the distribution area; wherein, the collaborative absorption maintenance signal includes the reference load reduction factor K_base;

[0011] S5. After receiving the coordinated absorption maintenance signal, the photovoltaic inverter executes the local load reduction decision process to obtain an execution load reduction coefficient K_i. Within the preset adjustment time T_s, according to the execution load reduction coefficient K_i and the smooth load reduction curve, the output power of the photovoltaic inverter is adjusted to the target value, and the output power of the photovoltaic inverter is adjusted to be within the preset range of the error between the target value and the target value.

[0012] Preferably, in S1, the preset frequency value is 100Hz.

[0013] Preferably, in S2, the load-photovoltaic ratio K is the ratio of the real-time total load to the total rated photovoltaic output.

[0014] Preferably, in S3, the threshold generation mechanism is as follows: when K < 0.3, ε = 0.1 Hz / s²; when 0.3 ≤ K < 0.6, ε = 0.5 Hz / s²; when K ≥ 0.6, ε = 1.0 Hz / s².

[0015] Preferably, in S4, the coordinated absorption maintenance signal also includes a time stamp. After receiving the coordinated absorption maintenance signal, the photovoltaic inverter verifies the time stamp. Only when the difference between the timestamp of the time stamp and the timestamp of the current time is less than a preset time threshold, step S5 is executed.

[0016] The preset time threshold ranges from 200 milliseconds to 1 second.

[0017] Preferably, in S5, the local load reduction decision process is executed as follows:

[0018] S51. Obtain the current output power P_c and the rated output power of the photovoltaic inverter, and use the ratio of the current output power P_c to the rated output power as the local weighting factor.

[0019] S52. The photovoltaic inverter generates a delay time that is randomly distributed within a preset time range, and after waiting for the delay time, executes step S53.

[0020] S53. The photovoltaic inverter uses the product of the reference derating factor K_base and the local weighting factor as the execution derating factor Ki.

[0021] Preferably, in S52, the photovoltaic inverter generates a delay time that is randomly distributed within a preset time range, as follows:

[0022] Obtain the unique device serial number of the photovoltaic inverter;

[0023] Obtain the hash value of the unique device serial number, convert the hash value of the unique device serial number into an integer, and obtain the integer hash value;

[0024] Obtain the maximum delay time within a preset time range, and perform a modulo operation on the maximum delay time using an integer hash value to obtain the delay time.

[0025] Preferably, the smooth load reduction curve is an exponential decay curve or a linear ramp descent curve.

[0026] A photovoltaic power consumption optimization control system for a distribution substation includes:

[0027] Status monitoring and sampling module: The intelligent terminal in the distribution area monitors the real-time frequency of the power frequency AC voltage at the grid connection point of the distribution area, and obtains the rate of change and acceleration of change of the real-time frequency d²f / dt² at a sampling frequency not lower than the preset frequency value.

[0028] Load-to-PV ratio generation module: The smart terminal in the distribution area obtains the real-time total load and total rated PV output of the distribution area, and obtains the load-to-PV ratio K;

[0029] Dynamic danger threshold generation module: The intelligent terminal of the transformer area generates a dynamic danger threshold ε based on the load photovoltaic ratio K and the threshold generation mechanism;

[0030] Cooperative signal generation and broadcasting module: When the intelligent terminal of the distribution area determines that the real-time frequency is higher than the rated frequency and the absolute value of the change acceleration is greater than the dynamic danger threshold ε, the intelligent terminal of the distribution area generates a cooperative absorption maintenance signal and broadcasts the cooperative absorption maintenance signal to all photovoltaic inverters participating in cooperative control in the distribution area; wherein, the cooperative absorption maintenance signal includes the reference load reduction factor K_base;

[0031] Local load derating decision and power adjustment module: After receiving the coordinated absorption maintenance signal, the photovoltaic inverter executes the local load derating decision process to obtain an execution load derating coefficient K_i; within the preset adjustment time T_s, according to the execution load derating coefficient K_i and the smooth load derating curve, the output power of the photovoltaic inverter is adjusted to the target value, and the output power of the photovoltaic inverter is adjusted to be within the preset range of the error between the target value and the target value.

[0032] The photovoltaic power consumption optimization control method and system for distribution substations proposed in this invention have the following beneficial technical effects:

[0033] 1. This application uses high-frequency sampling of the intelligent terminal in the distribution area to obtain real-time frequency and acceleration d²f / dt², and combines it with the load photovoltaic ratio K to generate a dynamic danger threshold ε. The real-time frequency of the power frequency AC voltage is higher than the rated frequency, and the absolute value of the acceleration is greater than the dynamic danger threshold ε, as the trigger condition for the coordinated load reduction maintenance signal. This enables early identification of frequency deterioration trends in the early stage of islanding. By broadcasting the coordinated load reduction maintenance signal including the reference load reduction factor K_base, the photovoltaic inverter executes a local load reduction decision process after receiving the coordinated load reduction maintenance signal to obtain an execution load reduction factor K_i. Within a preset adjustment time T_s, according to the execution load reduction factor K_i and the smooth load reduction curve, the output power of the photovoltaic inverter is adjusted to the target value, and the output power of the photovoltaic inverter is adjusted to be within the preset range of the error between the target value and the target value. This realizes distributed coordinated load reduction, effectively alleviating the technical problems of existing over-frequency load reduction response lag, inability to cope with the frequency rise caused by the automatic unloading of load, and ultimately the system frequency collapse.

[0034] 2. This application abandons the traditional frequency control approach that relies on the photovoltaic inverter detecting overfrequency and then implementing load reduction. Instead, it uses the real-time frequency of the power frequency AC voltage being higher than the rated frequency and the absolute value of the change acceleration being greater than the dynamic danger threshold ε as the trigger condition for the collaborative absorption and maintenance signal, rather than waiting for the frequency to spike before responding. Through a dual judgment mechanism, the intelligent terminal of the distribution area obtains the real-time frequency change rate and change acceleration d²f / dt² at a sampling frequency not lower than the preset frequency value. This allows it to detect the deterioration trend of the system frequency in the initial stage when the load begins to automatically unload and the frequency has not yet spiked significantly, thereby triggering the collaborative absorption and maintenance signal. Compared with the traditional overfrequency load reduction mode that waits until the frequency exceeds the standard before taking action, this significantly shortens the control response window period and effectively alleviates the problem of excessive power caused by load unloading, which ultimately leads to system frequency collapse.

[0035] 3. Addressing the potential for system instability caused by single-point failures or sudden power drops when relying on centralized control or synchronous load reduction for a large number of photovoltaic inverters within a distribution area, this application broadcasts a collaborative absorption and maintenance signal containing a baseline load reduction coefficient K_base via the distribution area's intelligent terminal. Photovoltaic inverters generate random delays based on local weighting factors and the hash value of their device serial numbers, and execute local load reduction decision-making processes. The local weighting factor ensures that inverters with higher current output experience greater load reduction, preventing excessive load reduction by inverters with lower output, thus matching the load reduction amount with the actual output. The random delay is generated based on the hash modulo of the device serial number, preventing sudden power drops caused by synchronous load reduction of all inverters, thereby preventing secondary disturbances to the system. Compared to traditional centralized control, distributed decision-making eliminates the risk of single-point failures, and photovoltaic inverters can adjust more flexibly. This effectively alleviates the problem of system oscillations caused by centralized control failures or synchronous load reduction of multiple inverters. Attached Figure Description

[0036] Figure 1 This is a flowchart of a photovoltaic power consumption optimization control method for a power distribution area according to the present invention;

[0037] Figure 2 This is a schematic diagram of the photovoltaic power consumption optimization control system for a distribution substation according to the present invention. Detailed Implementation

[0038] Embodiments of the present invention are described in detail below. Examples of these embodiments are illustrated in the accompanying drawings, wherein the same or similar symbols denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0039] like Figure 1 The photovoltaic power consumption optimization control method and system for a distribution substation, as shown, includes the following steps:

[0040] S1. The intelligent terminal in the distribution area monitors the real-time frequency of the power frequency AC voltage at the grid connection point of the distribution area, and obtains the rate of change and acceleration of change of the real-time frequency d²f / dt² at a sampling frequency not lower than the preset frequency value.

[0041] In an optional embodiment, in S1, the preset frequency value is 100Hz;

[0042] S2. The intelligent terminal in the distribution area obtains the real-time total load and total rated photovoltaic output of the distribution area, and obtains the load-to-photovoltaic ratio K.

[0043] In an optional embodiment, in S2, the load photovoltaic ratio K is the ratio of the real-time total load to the total rated photovoltaic output;

[0044] S3. The intelligent terminal in the distribution area generates a dynamic danger threshold ε based on the load photovoltaic ratio K and the threshold generation mechanism.

[0045] In an optional embodiment, in S3, the threshold generation mechanism is as follows: when K < 0.3, ε = 0.1 Hz / s²; when 0.3 ≤ K < 0.6, ε = 0.5 Hz / s²; when K ≥ 0.6, ε = 1.0 Hz / s².

[0046] To address the significant differences in system frequency degradation risk under varying real-time total load to total rated photovoltaic output ratios, fixed thresholds can lead to frequent false triggers due to sensitivity issues and missed control windows due to insensitivity. This solution designs a dynamic danger threshold ε generation mechanism based on the load-to-PV ratio K. When K < 0.3, the photovoltaic penetration rate is extremely high (ε = 0.1 Hz / s²), and a stricter dynamic danger threshold ε ensures early triggering control and prevents missed triggers. When 0.3 ≤ K < 0.6, ε = 0.5 Hz / s². When K ≥ 0.6, the photovoltaic-to-load ratio is relatively balanced (ε = 1.0 Hz / s²), and a more lenient dynamic danger threshold ε reduces false triggers under minor disturbances, balancing system stability and the economic efficiency of photovoltaic absorption. This ensures that the dynamic danger threshold ε matches the degree of imbalance between the current real-time total load and total rated photovoltaic output ratio. The smaller the load-to-PV ratio K, the more excessive the photovoltaic capacity and the higher the risk of frequency degradation, thus requiring a stricter threshold. This avoids the limitations of traditional fixed thresholds.

[0047] S4. When the intelligent terminal of the distribution area determines that the real-time frequency is higher than the rated frequency and the absolute value of the change acceleration is greater than the dynamic danger threshold ε.

[0048] The smart terminal in the distribution area generates a coordinated load reduction maintenance signal and broadcasts the coordinated load reduction maintenance signal to all photovoltaic inverters participating in the coordinated control within the distribution area; wherein, the coordinated load reduction maintenance signal includes the reference load reduction factor K_base;

[0049] As an explanation: the coordinated absorption maintenance signal is broadcast to all photovoltaic inverters participating in the coordinated control within the distribution area; broadcasting refers to a one-to-many data distribution mechanism in existing communication networks. Specifically, it means that the distribution area's intelligent terminal, through its communication interface, simultaneously sends the coordinated absorption maintenance signal to all photovoltaic inverters participating in the coordinated control in a unidirectional transmission manner, without needing to establish an independent point-to-point communication connection with any photovoltaic inverter beforehand. Photovoltaic inverters receiving this signal are not required to return a reception confirmation to the distribution area's intelligent terminal. Specific implementation methods for broadcasting include, for example, based on power line carrier communication, sending the coordinated absorption maintenance signal on the low-voltage power line of the distribution area, which can be received by all photovoltaic inverters connected to the same transformer; or based on a local wireless communication network, using wireless communication technology within the distribution area to simultaneously send the coordinated absorption maintenance signal to all photovoltaic inverters.

[0050] All photovoltaic inverters participating in the coordinated control refer to a subset of existing photovoltaic inverters within the distribution substation area.

[0051] In an optional embodiment, the baseline load reduction factor K_base is calculated according to the formula K_base=min(H, C×|d²f / dt²| / L);

[0052] Wherein, H is the upper limit of the derating factor, and the value ranges from 0.6 to 0.9; in an optional embodiment, H=0.8; the upper limit of the derating factor is used to prevent power deficit or frequency drop caused by excessive derating;

[0053] C is the sensitivity coefficient, which ranges from 0.05 to 0.3; in an optional embodiment, C = 0.1.

[0054] L is the reference acceleration, ranging from 0.5 Hz / s² to 2.0 Hz / s²; in an optional embodiment,

[0055] L = 1 Hz / s²;

[0056] This application abandons the traditional frequency control approach that relies on the photovoltaic inverter detecting overfrequency and then implementing load reduction. Instead, it uses the real-time frequency of the power frequency AC voltage being higher than the rated frequency and the absolute value of the change acceleration being greater than the dynamic danger threshold ε as the trigger condition for the collaborative absorption and maintenance signal, rather than waiting for the frequency to spike before responding. Through a dual judgment mechanism, the intelligent terminal in the distribution area obtains the real-time frequency change rate and change acceleration d²f / dt² at a sampling frequency not lower than the preset frequency value. This allows it to detect the deterioration trend of the system frequency in the initial stage when the load begins to automatically unload and the frequency has not yet spiked significantly, thereby triggering the collaborative absorption and maintenance signal. Compared with the traditional overfrequency load reduction mode that waits until the frequency exceeds the standard before taking action, this significantly shortens the control response window and effectively alleviates the problem of excessive power caused by load unloading, which ultimately leads to system frequency collapse.

[0057] In an optional embodiment, in S4, the coordinated absorption maintenance signal further includes a time stamp. After receiving the coordinated absorption maintenance signal, the photovoltaic inverter verifies the time stamp. Only when the difference between the timestamp of the time stamp and the timestamp of the current time is less than a preset time threshold, the subsequent step S5 is executed.

[0058] The preset time threshold ranges from 200 milliseconds to 1 second; in an optional embodiment, the preset time threshold is 500 milliseconds.

[0059] For clarification, the time stamp is the timestamp of the time when the coordinated absorption sustain signal is generated;

[0060] S5. After receiving the coordinated absorption maintenance signal, the photovoltaic inverter executes the local load reduction decision process to obtain an execution load reduction coefficient K_i. Within the preset adjustment time T_s, according to the execution load reduction coefficient K_i and the smooth load reduction curve, the output power of the photovoltaic inverter is adjusted to the target value, and the output power of the photovoltaic inverter is adjusted to be within the preset range of the error between the target value and the target value.

[0061] Adjust the output power of the photovoltaic inverter to be within a preset range from the target value, where the preset range is within ±5% of the target value.

[0062] This application addresses the technical problem of traditional overfrequency load balancing failing due to response lag and system frequency collapse when a distribution transformer area becomes a high-power island due to a fault in the upper-level power grid. This issue arises because the photovoltaic output far exceeds the load, and the automatic current reduction of inverter air conditioners, water pumps, and industrial motors as the frequency increases exacerbates the frequency rise, leading to the failure of traditional overfrequency load balancing methods due to response lag. The application utilizes high-frequency sampling at the distribution transformer's intelligent terminal to obtain real-time frequency and acceleration d²f / dt², combined with the load-to-photovoltaic ratio K. A dynamic danger threshold ε is generated. The trigger condition for the coordinated load shedding maintenance signal is that the real-time frequency of the power frequency AC voltage is higher than the rated frequency and the absolute value of the change acceleration is greater than the dynamic danger threshold ε. This enables early identification of frequency deterioration trends in the early stages of islanding. By broadcasting a coordinated load shedding maintenance signal including a reference load shedding factor K_base, the photovoltaic inverter executes a local load shedding decision process after receiving the coordinated load shedding maintenance signal to obtain an execution load shedding factor K_i. Within a preset adjustment time T_s, the output power of the photovoltaic inverter is adjusted to the target value according to the execution load shedding factor K_i and the smooth load shedding curve. The output power of the photovoltaic inverter is adjusted to be within the preset range of the error between the photovoltaic inverter output power and the target value, realizing distributed coordinated load shedding. This effectively alleviates the technical problems of existing over-frequency load shedding response lag, inability to cope with the frequency rise caused by the automatic unloading of load, and ultimately the system frequency collapse.

[0063] In an optional embodiment, in S5, a local load reduction decision process is executed as follows:

[0064] S51. Obtain the current output power P_c and the rated output power of the photovoltaic inverter, and use the ratio of the current output power P_c to the rated output power as the local weighting factor.

[0065] S52. The photovoltaic inverter generates a delay time that is randomly distributed within a preset time range, and after waiting for the delay time, executes step S53.

[0066] In one optional embodiment, the preset time range is 0 to 100 milliseconds;

[0067] S53. The photovoltaic inverter uses the product of the reference derating factor K_base and the local weighting factor as the execution derating factor Ki.

[0068] In an optional embodiment, in S52, the photovoltaic inverter generates a delay time that is randomly distributed within a preset time range, as follows:

[0069] Obtain the unique device serial number of the photovoltaic inverter;

[0070] Obtain the hash value of the unique device serial number, convert the hash value of the unique device serial number into an integer, and obtain the integer hash value;

[0071] Obtain the maximum delay time within a preset time range, and perform a modulo operation on the maximum delay time using an integer hash value to obtain the delay time;

[0072] Since the randomly distributed delay time is generated based on the equipment serial number of the photovoltaic inverter, it ensures that the delay time generated by different photovoltaic inverters in the same area is different;

[0073] To address the potential instability issues arising from single-point failures or sudden power drops caused by centralized control or synchronous load reduction of numerous photovoltaic inverters within a distribution area, this application addresses this problem by broadcasting a collaborative absorption and maintenance signal containing a baseline load reduction coefficient K_base via the distribution area's intelligent terminal. Photovoltaic inverters generate random delays based on local weighting factors and the hash value of their device serial numbers, and execute local load reduction decision-making processes. The local weighting factor ensures that inverters with higher current output experience larger load reductions, preventing excessive load reduction by low-output inverters and achieving a match between load reduction and actual output. The random delay is generated based on the hash modulo operation of the device serial number, preventing sudden power drops caused by synchronous load reduction of all inverters, thus preventing secondary disturbances to the system. Compared to traditional centralized control, distributed decision-making eliminates the risk of single-point failures, and photovoltaic inverters can adjust more flexibly. This effectively mitigates the problem of system oscillations caused by centralized control failures or synchronous load reduction of multiple inverters.

[0074] In an optional embodiment, the smooth load drop curve is an exponential decay curve or a linear ramp descent curve.

[0075] In an optional embodiment, the smooth load reduction curve is an exponential decay curve, expressed as:

[0076] P(t)=P_c×[1-K_i×(1-e^(-t / τ))];

[0077] Where P(t) is the output power of the photovoltaic inverter at time t;

[0078] t=0 is the starting point at which each photovoltaic inverter begins to reduce its output power according to the smooth load reduction curve after completing the local load reduction decision process.

[0079] τ is the decay time constant, and the value of τ ranges from 1 second to 3 seconds; in an optional embodiment, the value of τ is 2 seconds.

[0080] The preset adjustment time T_s is 4τ;

[0081] e^ is the natural exponential function;

[0082] In an optional embodiment, the smooth load reduction curve is a linear ramp descent curve, expressed as:

[0083] P(t)=P_c×(1-K_i×min(1,t / T));

[0084] Where P(t) is the output power of the photovoltaic inverter at time t;

[0085] t=0 is the starting point at which each photovoltaic inverter begins to reduce its output power according to the smooth load reduction curve after completing the local load reduction decision process.

[0086] T represents the ramp descent time, which ranges from 3 to 8 seconds; in an optional embodiment, T is set to 5 seconds.

[0087] The preset adjustment time T_s is equal to T.

[0088] To address the issues of system fluctuations caused by sudden power changes in traditional load derating methods, or subsequent frequency drops and photovoltaic waste due to excessive load derating, this application adjusts the output power of the photovoltaic inverter towards the target value according to the load derating factor K_i and a smooth load derating curve, ensuring that the output power of the photovoltaic inverter is within a preset range from the target value. The smooth load derating curve is either an exponential decay curve or a linear ramp-down curve. The smooth load derating curve avoids the impact of sudden power changes on the system frequency and voltage, ensuring stable system operation during the load derating process. The upper limit of the load derating factor H prevents excessive load derating, avoiding both sudden frequency drops due to excessive load derating and unnecessary waste of photovoltaic output, effectively mitigating secondary system disturbances during the load derating process and the economic losses and frequency deficits caused by excessive load derating.

[0089] like Figure 2 The photovoltaic power consumption optimization control system for a distribution substation shown includes:

[0090] Status monitoring and sampling module: The intelligent terminal in the distribution area monitors the real-time frequency of the power frequency AC voltage at the grid connection point of the distribution area, and obtains the rate of change and acceleration of change of the real-time frequency d²f / dt² at a sampling frequency not lower than the preset frequency value.

[0091] Load-to-PV ratio generation module: The smart terminal in the distribution area obtains the real-time total load and total rated PV output of the distribution area, and obtains the load-to-PV ratio K;

[0092] Dynamic danger threshold generation module: The intelligent terminal of the transformer area generates a dynamic danger threshold ε based on the load photovoltaic ratio K and the threshold generation mechanism;

[0093] Cooperative signal generation and broadcasting module: When the intelligent terminal of the distribution area determines that the real-time frequency is higher than the rated frequency and the absolute value of the change acceleration is greater than the dynamic danger threshold ε, the intelligent terminal of the distribution area generates a cooperative absorption maintenance signal and broadcasts the cooperative absorption maintenance signal to all photovoltaic inverters participating in cooperative control in the distribution area; wherein, the cooperative absorption maintenance signal includes the reference load reduction factor K_base;

[0094] Local load derating decision and power adjustment module: After receiving the coordinated absorption maintenance signal, the photovoltaic inverter executes the local load derating decision process to obtain an execution load derating coefficient K_i; within the preset adjustment time T_s, according to the execution load derating coefficient K_i and the smooth load derating curve, the output power of the photovoltaic inverter is adjusted to the target value, and the output power of the photovoltaic inverter is adjusted to be within the preset range of the error between the target value and the target value.

[0095] For clarification, "acquisition" in this application refers to obtaining the required content or data using existing technical means.

[0096] Furthermore, any content not described in detail in this specification is existing technology known to those skilled in the art.

[0097] In the embodiments provided by this invention, it should be understood that the disclosed system or method can be implemented in other ways. For example, the embodiments of the invention described above are merely illustrative; for instance, the division of modules is only a logical functional division, and there may be other division methods in actual implementation.

[0098] The modules described as separate components may or may not be physically separate. The components shown as modules may or may not be physical modules; they may be located in one place or distributed across multiple network modules. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs.

[0099] Furthermore, the functional modules in the various embodiments of the present invention can be integrated into one processing module, or each module can exist physically separately, or two or more modules can be integrated into one module. The integrated module can be implemented in hardware or in the form of hardware plus software functional modules.

[0100] For those skilled in the art, it is obvious that the present invention is not limited to the details of the above exemplary embodiments, and that the present invention can be implemented in other specific forms without departing from the basic characteristics of the present invention.

[0101] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A method for optimizing and controlling the photovoltaic power consumption of a distribution substation, characterized in that, Includes the following steps: S1. The intelligent terminal in the distribution area monitors the real-time frequency of the power frequency AC voltage at the grid connection point of the distribution area, and obtains the rate of change and acceleration of change of the real-time frequency d²f / dt² at a sampling frequency not lower than the preset frequency value. S2. The intelligent terminal in the distribution area obtains the real-time total load and total rated photovoltaic output of the distribution area, and obtains the load-to-photovoltaic ratio K. S3. The intelligent terminal of the transformer area generates a dynamic danger threshold ε based on the load photovoltaic ratio K and the threshold generation mechanism. S4. When the intelligent terminal of the distribution area determines that the real-time frequency is higher than the rated frequency and the absolute value of the change acceleration is greater than the dynamic danger threshold ε, the intelligent terminal of the distribution area generates a collaborative absorption maintenance signal and broadcasts the collaborative absorption maintenance signal to all photovoltaic inverters participating in collaborative control within the distribution area; wherein, the collaborative absorption maintenance signal includes the reference load reduction factor K_base; S5. After receiving the coordinated absorption maintenance signal, the photovoltaic inverter executes the local load reduction decision process to obtain an execution load reduction coefficient K_i. Within the preset adjustment time T_s, according to the execution load reduction coefficient K_i and the smooth load reduction curve, the output power of the photovoltaic inverter is adjusted to the target value, and the output power of the photovoltaic inverter is adjusted to be within the preset range of the error between the target value and the target value.

2. The method of claim 1, wherein, In S2, the load-to-photovoltaic ratio K is the ratio of the real-time total load to the total rated photovoltaic output.

3. The method of claim 1, wherein, In S3, the threshold generation mechanism is as follows: when K < 0.3, ε = 0.1 Hz / s²; when 0.3 ≤ K < 0.6, ε = 0.5 Hz / s²; when K ≥ 0.6, ε = 1.0 Hz / s².

4. The method of claim 1, wherein, In S4, the coordinated absorption maintenance signal also includes a time stamp. After receiving the coordinated absorption maintenance signal, the photovoltaic inverter verifies the time stamp. Only when the difference between the timestamp of the time stamp and the timestamp of the current time is less than the preset time threshold, step S5 is executed. The preset time threshold ranges from 200 milliseconds to 1 second.

5. The photovoltaic power consumption optimization control method for a distribution substation according to claim 1, characterized in that, In S5, the local load reduction decision process is executed as follows: S51. Obtain the current output power P_c and the rated output power of the photovoltaic inverter, and use the ratio of the current output power P_c to the rated output power as the local weighting factor. S52. The photovoltaic inverter generates a delay time that is randomly distributed within a preset time range, and after waiting for the delay time, executes step S53. S53. The photovoltaic inverter uses the product of the reference derating factor K_base and the local weighting factor as the execution derating factor Ki.

6. The photovoltaic power consumption optimization control method for a distribution substation according to claim 5, characterized in that, In S52, the photovoltaic inverter generates a delay time that is randomly distributed within a preset time range, as follows: Obtain the unique device serial number of the photovoltaic inverter; Obtain the hash value of the unique device serial number, convert the hash value of the unique device serial number into an integer, and obtain the integer hash value; Obtain the maximum delay time within a preset time range, and perform a modulo operation on the maximum delay time using an integer hash value to obtain the delay time.

7. The photovoltaic power consumption optimization control method for a distribution substation according to claim 1, characterized in that, The smooth load reduction curve is either an exponential decay curve or a linear ramp-down curve.

8. A photovoltaic power consumption optimization control system for a distribution substation, used in accordance with the photovoltaic power consumption optimization control method for a distribution substation as described in any one of claims 1 to 7, characterized in that, include: Status monitoring and sampling module: The intelligent terminal in the distribution area monitors the real-time frequency of the power frequency AC voltage at the grid connection point of the distribution area, and obtains the rate of change and acceleration of change of the real-time frequency d²f / dt² at a sampling frequency not lower than the preset frequency value. Load-to-PV ratio generation module: The smart terminal in the distribution area obtains the real-time total load and total rated PV output of the distribution area, and obtains the load-to-PV ratio K; Dynamic danger threshold generation module: The intelligent terminal of the transformer area generates a dynamic danger threshold ε based on the load photovoltaic ratio K and the threshold generation mechanism; Cooperative signal generation and broadcasting module: When the intelligent terminal of the distribution area determines that the real-time frequency is higher than the rated frequency and the absolute value of the change acceleration is greater than the dynamic danger threshold ε, the intelligent terminal of the distribution area generates a cooperative absorption maintenance signal and broadcasts the cooperative absorption maintenance signal to all photovoltaic inverters participating in cooperative control in the distribution area; wherein, the cooperative absorption maintenance signal includes the reference load reduction factor K_base; Local load derating decision and power adjustment module: After receiving the coordinated absorption maintenance signal, the photovoltaic inverter executes the local load derating decision process to obtain an execution load derating coefficient K_i; within the preset adjustment time T_s, according to the execution load derating coefficient K_i and the smooth load derating curve, the output power of the photovoltaic inverter is adjusted to the target value, and the output power of the photovoltaic inverter is adjusted to be within the preset range of the error between the target value and the target value.

Images