Station transient power angle control method and device for multi-grid-connected mode photovoltaic backup participation

Abstract

The application provides a kind of multi-grid-connected mode photovoltaic backup participation station transient power angle control method and device, method includes creating network type inverter, the active power parameter of the direct current side of each follow network type inverter and the active power parameter of alternating current side and the discharge power parameter of battery energy storage respectively time series;Determine the influence factor of the active power parameter of direct current side and the active power parameter of alternating current side and discharge power parameter in next time;Based on influence factor, determine the active power prediction value of direct current side and the active power parameter prediction value of alternating current side and discharge power parameter prediction value;The active power prediction value of direct current side and the active power parameter prediction value of alternating current side and discharge power parameter prediction value are normalized;Based on each normalized value, determine the transient power angle index prediction value in next time;Based on transient power angle index prediction value control network type inverter, follow network type inverter and the parameter of battery energy storage, improve the stability of power system.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of photovoltaic backup participating station transient power angle control technology, and particularly relates to a multi-grid-connected-mode photovoltaic backup participating station transient power angle control method and device. BACKGROUND

[0002] In recent years, new energy power generation represented by photovoltaic has developed rapidly, and the capacity connected to the power grid has been increasing, reducing the use of fossil energy and environmental pollution. With the increasing penetration rate of photovoltaic systems in the power grid and the development of photovoltaic inverter technology, photovoltaic systems have begun to take on more grid support functions, including voltage and frequency support, which makes photovoltaic systems participate in power system stability and transient response to some extent.

[0003] Because photovoltaic systems do not have the traditional concept of "transient power angle" (because photovoltaic systems do not produce power through rotating rotors like synchronous generators, nor do they have physical rotors participating in synchronous operation of the power system), the transient power angle stability of new energy stations has not been fully quantitatively evaluated, which limits the effective participation of new energy stations in power system stability control. SUMMARY

[0004] The present application provides a multi-grid-connected-mode photovoltaic backup participating station transient power angle control method and device to solve the technical problem that the existing technology cannot accurately predict the trend of transient power angle changes, resulting in the inability to maintain the stability of the power system.

[0005] In one aspect, the present application provides a multi-grid-connected-mode photovoltaic backup participating station transient power angle control method, comprising:

[0006] Obtaining the DC side active power parameters and AC side active power parameters of the grid-connected inverter and the grid-following inverter of the photovoltaic backup participating station for determining the transient power angle index of the station, and the discharge power parameters of the battery energy storage under the multi-grid-connected mode;

[0007] Creating a time series of the DC side active power parameters and AC side active power parameters of the grid-connected inverter and the grid-following inverter, and the discharge power parameters of the battery energy storage, respectively;

[0008] Based on each of the time series, determining the influence factors of the DC side active power parameters and AC side active power parameters of the grid-connected inverter and the grid-following inverter, and the discharge power parameters of the battery energy storage at the next time;

[0009] Based on the influencing factors, determining the DC side active power prediction value and AC side active power parameter prediction value of each of the grid-forming inverter and the grid-following inverter, as well as the battery energy storage discharge power parameter prediction value at the next moment;

[0010] Normalizing the DC side active power prediction value and AC side active power parameter prediction value and battery energy storage discharge power parameter prediction value of each of the grid-forming inverter and the grid-following inverter to obtain corresponding normalized values;

[0011] Based on the normalized values, a predicted value of a transient power angle index of a station with photovoltaic backup participation in a multi-grid mode at a next moment is determined;

[0012] Based on the transient power angle index prediction value, the DC side active power parameters and AC side active power parameters of the grid-forming inverter and the grid-following inverter, as well as the discharge power parameters of the battery energy storage, are controlled.

[0013] According to a method for controlling transient power angle of a station with photovoltaic standby participation in multiple grid-connected modes provided by the present invention, the formula for determining the transient power angle index of the station is shown in the following formula (1) based on the DC side active power parameters and AC side active power parameters of the grid-connected inverter and the grid-following inverter of the photovoltaic standby participating station and the discharge power parameters of the battery energy storage. The time series can be shown in the following formula (2):

[0014]

[0015] Among them, TSPA SUE is the transient power angle index of the station; T1, T2, K, T n ,K,T k are the moments in a fixed time interval, where k is a natural number, representing the kth moment; n is a natural number, representing the nth moment, and n ranges from 1 to k; T n Total active power on the AC side of the grid-connected photovoltaic inverter at all times; T n Total active power on the DC side of the grid-connected photovoltaic inverter at any given moment; P rpAC,max T1, T2, K, T n ,K,T k The maximum value of the total active power on the AC side of the grid-connected photovoltaic inverter during these k fixed time intervals; P rpDC,max T1, T2, K, T n ,K,T k The maximum active power on the DC side of the grid-connected photovoltaic inverter during these k fixed time intervals; T n Always follow the total active power on the AC side of the grid-connected photovoltaic inverter; P is the total active power of the grid-connected type photovoltaic inverter at the T n P is the total active power of the grid-connected type photovoltaic inverter at the T ctAC,max P is the total active power of the grid-connected type photovoltaic inverter at the T n P is the total active power of the grid-connected type photovoltaic inverter at the T k P is the maximum active power of the grid-connected type photovoltaic inverter at the T ctDC,max P is the total active power of the grid-connected type photovoltaic inverter at the T n P is the total active power of the grid-connected type photovoltaic inverter at the T k P is the maximum active power of the grid-connected type photovoltaic inverter at the T P is the total active power of the grid-connected type photovoltaic inverter at the T n P is the total active power of the grid-connected type photovoltaic inverter at the T bes,max P is the total active power of the grid-connected type photovoltaic inverter at the T n P is the total active power of the grid-connected type photovoltaic inverter at the T k P is the maximum active power of the grid-connected type photovoltaic inverter at the T

[0016] According to the multi-grid mode photovoltaic standby participating station transient power angle control method provided by the application, the influence factor is shown in the following formula (3):

[0017]

[0018] Wherein, P is the influence factor of the DC side active power parameter and the AC side active power parameter of the grid-connected type inverter and the grid-connected type inverter and the battery energy storage discharge power parameter of the multi-grid mode photovoltaic standby at the T n P is the influence factor of the DC side active power parameter and the AC side active power parameter of the grid-connected type inverter and the grid-connected type inverter and the battery energy storage discharge power parameter of the multi-grid mode photovoltaic standby at the T rpDC,min P is the minimum value of the total active power of the grid-connected type inverter DC side at T1, T2, K, T n P is the minimum value of the total active power of the grid-connected type inverter DC side at T1, T2, K, T k P is the maximum value of the total active power of the grid-connected type inverter AC side at T1, T2, K, T rpAC,max P is the maximum value of the total active power of the grid-connected type inverter AC side at T1, T2, K, T n P is the minimum value of the total active power of the grid-connected type inverter DC side at T1, T2, K, T k P is the minimum value of the total active power of the grid-connected type inverter DC side at T1, T2, K, T ctDC,min P is the maximum value of the total active power of the grid-connected type inverter AC side at T1, T2, K, T n P is the maximum value of the total active power of the grid-connected type inverter AC side at T1, T2, K, T k P is the minimum value of the total active power of the grid-connected type inverter DC side at T1, T2, K, T ctAC,max P is the minimum value of the total active power of the grid-connected type inverter DC side at T1, T2, K, T n P is the maximum value of the total active power of the grid-connected type inverter AC side at T1, T2, K, T k P is the maximum value of the total active power of the grid-connected type inverter AC side at T1, T2, K, Tbes,max The battery energy storage discharge power is T1, T2, K, T n ,K,T k The maximum value of the measured values ​​at these k fixed time intervals.

[0019] According to a method for controlling transient power angle of a station with photovoltaic standby participation in multiple grid-connected modes provided by the present invention, the DC side active power prediction value and AC side active power parameter prediction value of each of the grid-connected inverter and the grid-following inverter, as well as the battery energy storage discharge power parameter prediction value, are as shown in the following formula (4):

[0020]

[0021] in, T k+1 The predicted value of the total active power on the DC side of the grid-connected inverter at each moment; T k+1 The predicted value of the total active power on the AC side of the grid-connected inverter at any moment; T k+1 Always follow the predicted value of the total active power on the DC side of the grid-connected inverter; T k+1 Always follow the predicted value of the total active power on the AC side of the grid-connected inverter; T k+1 The predicted value of battery energy storage discharge power at the moment.

[0022] According to a method for controlling transient power angle of a station with photovoltaic backup in multiple grid-connected modes provided by the present invention, the corresponding normalized values ​​are shown in the following formula (5):

[0023]

[0024] in, T k+1 Normalized value of the total active power prediction value of the DC side of the grid-connected inverter at each moment; T k+1 Normalized value of the total active power prediction value of the AC side of the grid-connected inverter at any moment; T k+1 Normalized value of the total active power prediction value of the DC side of the grid-connected inverter at all times; T k+1 Normalized value of the total active power prediction value of the AC side of the grid-connected inverter at all times; T k+1 Normalized value of the battery energy storage discharge power prediction value at the moment.

[0025] According to a method for controlling transient power angle of a station with photovoltaic backup in multiple grid-connected modes provided by the present invention, the predicted value of the transient power angle index of the station is shown in the following formula (6):

[0026]

[0027] wherein, represents the transient power angle index prediction value of the substation.

[0028] According to the substation transient power angle control method of the multi-grid-connected mode photovoltaic backup participated by the application, based on the transient power angle index prediction value, the active power parameters of the direct current side and the alternating current side of the grid-connected inverter and the grid-following inverter and the discharge power parameter of the battery energy storage are controlled, including:

[0029] If the transient power angle index prediction value is greater than or equal to the preset threshold value, the multi-grid-connected mode photovoltaic backup and the active power of the substation or the discharge power of the battery energy storage are increased.

[0030] If the transient power angle index prediction value is less than the threshold value, the multi-grid-connected mode photovoltaic backup and the active power of the substation or the discharge power of the battery energy storage are reduced.

[0031] According to the substation transient power angle control method of the multi-grid-connected mode photovoltaic backup participated by the application, the preset threshold value is 0.43.

[0032] In order to facilitate understanding, the application will be introduced in more detail below. Assuming that the fixed time interval is 10 minutes, 5 measurement time points are selected, that is, k is 5. That is, the grid-connected inverter direct current side active power measurement value The grid-connected inverter alternating current side active power measurement value is measured at the time points T1, T2, T3, T4, T5 of the fixed time interval The grid-following inverter direct current side active power measurement value is measured at the time points T1, T2, T3, T4, T5 of the fixed time interval The grid-following inverter alternating current side active power measurement value is measured at the time points T1, T2, T3, T4, T5 of the fixed time interval The battery energy storage discharge power measurement value is measured at the time points T1, T2, T3, T4, T5 of the fixed time interval According to all the above obtained measurement values, the time sequence of the grid-connected mode, the grid-following inverter direct current side and alternating current side active power parameters and the battery energy storage discharge power parameters of the multi-grid-connected mode photovoltaic backup and the substation are established as shown in the following (7):

[0033]

[0034] When k is 5, the obtained influence factors include

[0035] When k is 5, k is the current time, and k+1 is the next time, the above formula (4) is specifically as follows formula (8):

[0036]

[0037] wherein, is the predicted value of the total active power of the grid-connected type inverter on the DC side at T6; is the predicted value of the total active power of the grid-connected type inverter on the AC side at T6; is the predicted value of the total active power of the grid-following type inverter on the DC side at T6; is the predicted value of the total active power of the grid-following type inverter on the AC side at T6; is the predicted value of the battery energy storage discharge power at T6.

[0038] When k is 5, the result of formula (5) is as shown in the following formula (9):

[0039]

[0040] wherein, is the normalized value of the predicted value of the total active power of the grid-connected type inverter on the DC side at T6; is the normalized value of the predicted value of the total active power of the grid-connected type inverter on the AC side at T6; is the normalized value of the predicted value of the total active power of the grid-following type inverter on the DC side at T6; is the normalized value of the predicted value of the total active power of the grid-following type inverter on the AC side at T6; is the normalized value of the predicted value of the battery energy storage discharge power at T6.

[0041] When k is 5, the result of formula (6) is as shown in the following formula (10):

[0042]

[0043] On the other hand, the application also provides a station transient power angle control device for multiple grid-connected mode photovoltaic backup participation, comprising:

[0044] An acquisition module acquires the DC side active power parameters and AC side active power parameters of the grid-connected type inverter and the grid-following type inverter of the photovoltaic backup participation station for determining the station transient power angle index and the discharge power parameters of the battery energy storage under multiple grid-connected mode;

[0045] A time sequence module creates a time sequence of the DC side active power parameters and AC side active power parameters of the grid-connected type inverter and the grid-following type inverter and the discharge power parameters of the battery energy storage;

[0046] An influence factor module determines, based on the time series, influence factors of the active power parameters of the DC side and the AC side of the grid-forming inverter and the grid-following inverter and the discharge power parameter of the battery energy storage at the next moment;

[0047] A first prediction module determines, based on the influence factors, the predicted values of the active power parameters of the DC side and the AC side of the grid-forming inverter and the grid-following inverter and the predicted value of the discharge power parameter of the battery energy storage at the next moment;

[0048] A normalization module normalizes the predicted values of the active power parameters of the DC side and the AC side of the grid-forming inverter and the grid-following inverter and the predicted value of the discharge power parameter of the battery energy storage to obtain corresponding normalized values;

[0049] A second prediction module determines, based on the normalized values, a predicted value of a transient power angle index of the power station in the multi-grid-connected mode at the next moment.

[0050] A control module controls, based on the predicted value of the transient power angle index, the active power parameters of the DC side and the AC side of the grid-forming inverter and the grid-following inverter and the discharge power parameter of the battery energy storage.

[0051] In another aspect, the application also provides an electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the above-mentioned method for controlling the transient power angle of the power station in the multi-grid-connected mode of the photovoltaic backup.

[0052] The application provides a multi-grid mode photovoltaic backup participating station transient power angle control method and device, which creates time series of active power parameters of a direct current side and active power parameters of an alternating current side of a grid-forming inverter and a grid-following inverter and a discharge power parameter of a battery energy storage; determines an influence factor of the active power parameters of the direct current side and the active power parameters of the alternating current side of the grid-forming inverter and the grid-following inverter and the discharge power parameter of the battery energy storage at the next moment based on the time series; determines a direct current side active power prediction value and an alternating current side active power parameter prediction value and a battery energy storage discharge power parameter prediction value of the grid-forming inverter and the grid-following inverter at the next moment based on the influence factor; performs normalization processing on the direct current side active power prediction value and the alternating current side active power parameter prediction value and the battery energy storage discharge power parameter prediction value of the grid-forming inverter and the grid-following inverter to obtain corresponding normalized values; determines a photovoltaic backup participating station transient power angle index prediction value at the next moment in the multi-grid mode based on the normalized values; and controls the active power parameters of the direct current side and the active power parameters of the alternating current side of the grid-forming inverter and the grid-following inverter and the discharge power parameter of the battery energy storage based on the transient power angle index prediction value, so that the transient power angle change trend is accurately predicted, the new energy station effectively participates in the power system stability control, and the stability of the power system is improved. BRIEF DESCRIPTION OF DRAWINGS

[0053] In order to more clearly illustrate the technical solutions in the application or prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description are some embodiments of the application, and other drawings can be obtained by those skilled in the art without creative effort.

[0054] Figure 1 FIG. 1 is a flowchart of a multi-grid mode photovoltaic backup participating station transient power angle control method provided by an embodiment of the application;

[0055] Figure 2 FIG. 2 is a structural diagram of a multi-grid mode photovoltaic backup participating station transient power angle control device provided by an embodiment of the application;

[0056] Figure 3 FIG. 3 is a structural diagram of an electronic device provided by an embodiment of the application. DETAILED DESCRIPTION

[0057] In order to make the objects, technical solutions and advantages of the present application clearer, the technical solutions in the present application will be described clearly and completely below with reference to the drawings in the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work belong to the protection scope of the present application.

[0058] Figure 1 is a flowchart of a method for transient power angle control of a station participating in multi-grid-connected mode photovoltaic backup provided by an embodiment of the present application.

[0059] Referring to Figure 1 , the method for transient power angle control of a station participating in multi-grid-connected mode photovoltaic backup can include the following steps.

[0060] 101, in the multi-grid-connected mode, the DC side active power parameters and the AC side active power parameters of the grid-connected type inverter and the grid-following type inverter of the photovoltaic backup participating station for determining the station transient power angle index and the discharge power parameters of the battery energy storage are obtained.

[0061] In this step, the calculation relationship between the station transient power angle index and the DC side active power parameters and the AC side active power parameters of the grid-connected type inverter and the grid-following type inverter and the discharge power parameters of the battery energy storage of the multi-grid-connected mode photovoltaic backup participating station can be defined in advance.

[0062] 102, the time series of the DC side active power parameters and the AC side active power parameters of the grid-connected type inverter and the grid-following type inverter and the discharge power parameters of the battery energy storage are created respectively.

[0063] In this step, the calculation relationship formula of the station transient power angle index determined by the DC side active power parameters and the AC side active power parameters of the grid-connected type inverter and the grid-following type inverter and the discharge power parameters of the battery energy storage of the photovoltaic backup participating station is shown in the following formula (1):

[0064]

[0065] The time series can be shown in the following formula (2):

[0066]

[0067] Wherein, TSPA SUE is the station transient power angle index; T1, T2, K, T n , K, T k are each time of the fixed time interval, wherein k is a natural number, indicating the kth time; n is a natural number, indicating the nth time, n belongs to 1 to k; For T n The total active power of the grid-connected photovoltaic inverter on the AC side at the moment; For T n The total active power of the grid-connected photovoltaic inverter on the DC side at the moment; P rpAC,max For T1, T2, K, T n , K, T k The maximum total active power of the grid-connected photovoltaic inverter on the AC side in the k fixed time intervals; rpDC,max For T1, T2, K, T n , K, T k The maximum active power of the grid-connected photovoltaic inverter on the DC side in the k fixed time intervals; For T n The total active power of the grid-following photovoltaic inverter on the AC side at the moment; For T n The total active power of the grid-following photovoltaic inverter on the DC side at the moment; P ctAC,max For T1, T2, K, T n , K, T k The maximum active power of the grid-following photovoltaic inverter on the AC side in the k fixed time intervals; P ctDC,max For T1, T2, K, T n , K, T k The maximum active power of the grid-following photovoltaic inverter on the DC side in the k fixed time intervals; For T n The discharge power of the battery energy storage at the moment; P bes,max For T1, T2, K, T n , K, T k The maximum discharge power of the battery energy storage in the k fixed time intervals.

[0068] 103. Based on each time series, determine the influence factors of the DC side active power parameters and the AC side active power parameters of the grid-connected inverter and the grid-following inverter and the discharge power parameters of the battery energy storage at the next moment.

[0069] In this step, the influence factors are shown in the following formula (3):

[0070]

[0071] Among them, is the T nThe influence factor of the active power parameter of the direct current side of the grid-constructed inverter and the grid-followed inverter and the discharge power parameter of the battery energy storage of the photovoltaic backup at the next time point on the active power parameter of the direct current side of the grid-constructed inverter and the grid-followed inverter and the discharge power parameter of the battery energy storage of the photovoltaic backup at the next time point in the multi-grid-connected mode; P rpDC,min The total active power of the direct current side of the grid-constructed inverter at T1, T2, K, T n The total active power of the alternating current side of the grid-constructed inverter at T1, T2, K, T k The minimum value of the measurement value at the k fixed time intervals; P rpAC,max The total active power of the direct current side of the grid-constructed inverter at T1, T2, K, T n The total active power of the alternating current side of the grid-constructed inverter at T1, T2, K, T k The maximum value of the measurement value at the k fixed time intervals; P ctDC,min The total active power of the direct current side of the grid-followed inverter at T1, T2, K, T n The total active power of the alternating current side of the grid-followed inverter at T1, T2, K, T k The minimum value of the measurement value at the k fixed time intervals; P ctAC,max The total active power of the direct current side of the grid-followed inverter at T1, T2, K, T n The total active power of the alternating current side of the grid-followed inverter at T1, T2, K, T k The maximum value of the measurement value at the k fixed time intervals; P bes,max The total active power of the direct current side of the grid-followed inverter at T1, T2, K, T n The total active power of the alternating current side of the grid-followed inverter at T1, T2, K, T k The maximum value of the measurement value at the k fixed time intervals. The next time point is generally the next time point of the current time point. Generally, k time point can be regarded as the current time point, and k+1 time point can be regarded as the next time point.

[0072] 104. Based on the influence factor, the active power prediction value of the direct current side of the grid-constructed inverter and the grid-followed inverter and the active power parameter prediction value of the alternating current side and the discharge power parameter prediction value of the battery energy storage at the next time point are determined.

[0073] In this step, the active power prediction value of the direct current side of the grid-constructed inverter and the grid-followed inverter and the active power parameter prediction value of the alternating current side and the discharge power parameter prediction value of the battery energy storage are as shown in the following formula (4):

[0074]

[0075] Wherein, is the prediction value of the total active power of the direct current side of the grid-constructed inverter at T k+1 ; is the prediction value of the total active power of the alternating current side of the grid-constructed inverter at T k+1 ; is the prediction value of the total active power of the direct current side of the grid-followed inverter at Tk+1 the predicted value of the total active power of the grid-connected inverter at the time t; for T k+1 the predicted value of the total active power of the grid-following inverter at the time t; for T k+1 the predicted value of the discharging power of the battery energy storage at the time t.

[0076] 105, normalize the predicted values of the active power of the DC side and the predicted values of the active power parameters of the AC side of the grid-connected inverter and the grid-following inverter, and the predicted values of the discharging power parameters of the battery energy storage, to obtain the corresponding normalized values.

[0077] In this step, the corresponding normalized values are shown in the following formula (5):

[0078]

[0079] wherein, for T k+1 the normalized value of the predicted value of the total active power of the DC side of the grid-connected inverter at the time t; for T k+1 the normalized value of the predicted value of the total active power of the AC side of the grid-connected inverter at the time t; for T k+1 the normalized value of the predicted value of the total active power of the DC side of the grid-following inverter at the time t; for T k+1 the normalized value of the predicted value of the total active power of the AC side of the grid-following inverter at the time t; for T k+1 the normalized value of the predicted value of the discharging power of the battery energy storage at the time t.

[0080] 106, based on the normalized values, determine the predicted value of the transient power angle index of the station at the next time under the multi-grid-connected mode in which the photovoltaic backup participates.

[0081] In this step, the predicted value of the transient power angle index of the station is shown in the following formula (6):

[0082]

[0083] wherein, indicates the predicted value of the transient power angle index of the station.

[0084] 107, based on the predicted value of the transient power angle index, control the active power parameters of the DC side and the active power parameters of the AC side of the grid-connected inverter and the grid-following inverter, and the discharging power parameters of the battery energy storage.

[0085] In the embodiment, time series of the active power parameters of the direct current side and the active power parameters of the alternating current side of the grid-forming inverter and the grid-following inverter respectively and the discharge power parameters of the battery energy storage are created; based on the time series, influence factors of the active power parameters of the direct current side and the active power parameters of the alternating current side of the grid-forming inverter and the grid-following inverter respectively and the discharge power parameters of the battery energy storage at the next moment are determined; based on the influence factors, the predicted values of the active power of the direct current side, the predicted values of the active power of the alternating current side and the predicted values of the discharge power of the battery energy storage of the grid-forming inverter and the grid-following inverter at the next moment are determined; the predicted values of the active power of the direct current side, the predicted values of the active power of the alternating current side and the predicted values of the discharge power of the battery energy storage of the grid-forming inverter and the grid-following inverter are normalized to obtain corresponding normalized values; based on the normalized values, the predicted value of the transient power angle index of the station in the multi-grid-connected mode is determined; based on the predicted value of the transient power angle index, the active power parameters of the direct current side and the active power parameters of the alternating current side of the grid-forming inverter and the grid-following inverter and the discharge power parameters of the battery energy storage are controlled, the trend of the transient power angle is accurately predicted, the new energy station effectively participates in the stability control of the power system, and the stability of the power system is improved.

[0086] In an embodiment of the present specification, based on the predicted value of the transient power angle index, the active power parameters of the direct current side and the active power parameters of the alternating current side of the grid-forming inverter and the grid-following inverter and the discharge power parameters of the battery energy storage are controlled, which can include:

[0087] If the predicted value of the transient power angle index is greater than or equal to the preset threshold value, the active power of the multi-grid-connected mode photovoltaic reserve and the station or the discharge power of the battery energy storage is increased;

[0088] If the predicted value of the transient power angle index is less than the threshold value, the active power of the multi-grid-connected mode photovoltaic reserve and the station or the discharge power of the battery energy storage is reduced.

[0089] In the embodiment, the relationship between the predicted value of the transient power angle index and the preset threshold value can be compared. If the predicted value of the transient power angle index is greater than or equal to the preset threshold value, the active power of the multi-grid-connected mode photovoltaic reserve and the station or the discharge power of the battery energy storage is increased, and if the predicted value of the transient power angle index is less than the threshold value, the active power of the multi-grid-connected mode photovoltaic reserve and the station or the discharge power of the battery energy storage is reduced, so that the stability of the power grid system can be maintained.

[0090] In an embodiment of the present specification, the preset threshold value can be set, for example, set to any value between 0.4 and 0.5, which can be preferably 0.43.

[0091] In summary, the method of the present application monitors and predicts the predicted value of the active power parameters of the grid-connected type and grid-following type inverters on the DC side and AC side of the multi-grid-connected mode photovoltaic backup and the battery energy storage discharge power parameter in real time, calculates the transient power angle index prediction value of the station participated by the multi-grid-connected mode photovoltaic backup according to the obtained monitoring parameters and the predicted value of the predicted value of the next time parameter, adjusts the active power parameters of the grid-connected type and grid-following type inverters on the DC side and AC side of the multi-grid-connected mode photovoltaic backup and the battery energy storage discharge power in real time according to the calculation result, improves the transient power angle stability of the station participated by the multi-grid-connected mode photovoltaic backup, and can ensure the stability of the power system under the multi-grid-connected mode.

[0092] Based on the same overall inventive concept, the present application also protects a multi-grid-connected mode photovoltaic backup participated station transient power angle control device, as shown in Figure 2 Figure 2 It is a structural schematic diagram of the multi-grid-connected mode photovoltaic backup participated station transient power angle control device provided by the embodiment of the present application. The multi-grid-connected mode photovoltaic backup participated station transient power angle control device provided by the present application is described below, and the multi-grid-connected mode photovoltaic backup participated station transient power angle control device described below can be correspondingly referred to the multi-grid-connected mode photovoltaic backup participated station transient power angle control method described above.

[0093] The multi-grid-connected mode photovoltaic backup participated station transient power angle control device comprises an acquisition module 201, a time sequence module 202, an influence factor module 203, a first prediction module 204, a normalization module 205, a second prediction module 206 and a control module 207.

[0094] The acquisition module 201 acquires the DC side active power parameters and AC side active power parameters of the grid-connected type inverter and the grid-following type inverter of the photovoltaic backup participated station under the multi-grid-connected mode, and the discharge power parameter of the battery energy storage used for determining the station transient power angle index;

[0095] The time sequence module 202 creates a time sequence of the DC side active power parameters and AC side active power parameters of the grid-connected type inverter and the grid-following type inverter and the discharge power parameter of the battery energy storage;

[0096] The influence factor module 203 determines the influence factor of the DC side active power parameters and AC side active power parameters of the grid-connected type inverter and the grid-following type inverter and the discharge power parameter of the battery energy storage at the next time based on each of the time sequences;

[0097] ​The first prediction module 204 determines the DC side active power prediction value and the AC side active power parameter prediction value of the grid-forming inverter and the grid-following inverter respectively and the battery energy storage discharge power parameter prediction value based on the influence factor.

[0098] The normalization module 205 normalizes the DC side active power prediction value and the AC side active power parameter prediction value of the grid-forming inverter and the grid-following inverter respectively and the battery energy storage discharge power parameter prediction value to obtain the corresponding normalized values respectively.

[0099] The second prediction module 206 determines the substation transient power angle index prediction value of the photovoltaic backup participation in the multi-grid mode at the next moment based on the normalized values.

[0100] The control module 207 controls the DC side active power parameter and the AC side active power parameter of the grid-forming inverter and the grid-following inverter respectively and the discharge power parameter of the battery energy storage based on the transient power angle index prediction value.

[0101] Figure 3 is a structural schematic diagram of an electronic device provided by an embodiment of the present application. As shown in the figure, the electronic device can include a processor 310, a communications interface 320, a memory 330 and a communications bus 340, wherein the processor 310, the communications interface 320 and the memory 330 complete mutual communication through the communications bus 340. The processor 310 can invoke the logical instructions in the memory 330 to execute the substation transient power angle control method of the photovoltaic backup participation in the multi-grid mode. Figure 3

[0102] In addition, the logical instructions in the memory 330 described above can be implemented in the form of a software functional unit and sold or used as an independent product, which can be stored in a computer readable storage medium. Based on such understanding, the technical solutions of the present application essentially or the part that contributes to the prior art or part of the technical solutions can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including a plurality of instructions to make a computer device (which can be a personal computer, a server, or a network device, etc.) execute all or part of the steps of the method described in the embodiments of the present application. The aforementioned storage medium includes: a U disk, a mobile hard disk, a read-only memory (ROM, Read-Only Memory), a random access memory (RAM, Random Access Memory), a magnetic disk or an optical disk and various program codes that can be stored in the medium.

[0103] ​In another aspect, the present application also provides a computer program product, which comprises a computer program, the computer program being stored in a non-transitory computer readable storage medium, and the computer program, when executed by a processor, enables a computer to perform the multi-grid-connected mode photovoltaic backup participating power station transient power angle control method provided by the above methods.

[0104] In yet another aspect, the present application also provides a non-transitory computer readable storage medium, which stores a computer program, and the computer program, when executed by a processor, enables a computer to perform the multi-grid-connected mode photovoltaic backup participating power station transient power angle control method provided by the above methods.

[0105] The device embodiments described above are merely illustrative, wherein the units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, i.e., they may be located in one place, or distributed on multiple network units. Some or all of the modules can be selected to achieve the purpose of the embodiment scheme according to actual needs. Those skilled in the art can understand and implement it without creative labor.

[0106] From the above description of the embodiments, those skilled in the art can clearly understand that the embodiments can be realized by means of software plus necessary universal hardware platforms, and of course, can also be realized by hardware. Based on such understanding, the above technical solutions, essentially or in other words, the part that contributes to the prior art, can be embodied in the form of a software product, which can be stored in a computer readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes a number of instructions to make a computer device (which can be a personal computer, a server, or a network device, etc.) execute the methods described in each embodiment or some parts of the embodiments.

[0107] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, and not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement to some technical features; and these modifications or replacements do not make the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A method for controlling transient power angle of a station with photovoltaic backup in multiple grid-connected modes, characterized in that: include: Obtain the DC-side active power parameters and AC-side active power parameters of the grid-connected inverter and grid-following inverter of the PV standby participating station in the multi-grid mode, as well as the discharge power parameters of the battery energy storage, which are used to determine the transient power angle index of the station; Creating time series of the DC side active power parameters and AC side active power parameters of the grid-forming inverter and the grid-following inverter, and the discharge power parameters of the battery energy storage; Based on each of the time series, determining the influencing factors of the DC side active power parameters and AC side active power parameters of each of the grid-connecting inverter and the grid-following inverter and the discharge power parameter of the battery energy storage at the next moment; Based on the influencing factors, determining the DC side active power prediction value and AC side active power parameter prediction value of each of the grid-forming inverter and the grid-following inverter, as well as the battery energy storage discharge power parameter prediction value at the next moment; Normalizing the DC side active power prediction value and AC side active power parameter prediction value and battery energy storage discharge power parameter prediction value of each of the grid-forming inverter and the grid-following inverter to obtain corresponding normalized values; Based on the normalized values, a predicted value of a transient power angle index of a station with photovoltaic backup participation in a multi-grid mode at a next moment is determined; Based on the transient power angle index prediction value, controlling the DC side active power parameters and AC side active power parameters of the grid-forming inverter and the grid-following inverter, as well as the discharge power parameters of the battery energy storage; Among them, the formula for determining the transient power angle index of the station is shown in the following formula (1) based on the DC side active power parameters and AC side active power parameters of the grid-connected inverter and the grid-following inverter of the photovoltaic standby participating station and the discharge power parameters of the battery energy storage. The time series is shown in the following formula (2): （1） （2） in, is the station transient power angle index; are the moments at fixed time intervals, where is a natural number, indicating the kth moment; is a natural number, indicating the moments, n belongs to 1 to k; Total active power on the AC side of the grid-connected photovoltaic inverter at all times; Total active power on the DC side of the grid-connected photovoltaic inverter at all times; for The maximum value of the total active power on the AC side of the grid-connected photovoltaic inverter at a fixed time interval; The maximum active power of the DC side of the grid-connected photovoltaic inverter at a fixed time interval; Always follow the total active power on the AC side of the grid-connected photovoltaic inverter; Always follow the total active power of the DC side of the grid-connected photovoltaic inverter; The maximum active power on the AC side of the grid-connected photovoltaic inverter at a fixed time interval; The maximum active power on the DC side of the grid-connected photovoltaic inverter at a fixed time interval; Battery energy storage discharge power at all times; The maximum discharge power of the battery energy storage at a fixed time interval.

2. The method for controlling transient power angle of a station with photovoltaic backup in multiple grid-connected modes according to claim 1, characterized in that: The impact factor is shown in the following formula (3): (3) Among them, The factors affecting the DC side active power parameters and AC side active power parameters of the grid-connected inverter and grid-following inverter of the multi-grid-connected photovoltaic backup system and the station at the next moment, as well as the battery energy storage discharge power parameters, are as follows: The total active power on the DC side of the grid-connected inverter is The minimum value of the measurement value at a fixed time interval; The total active power on the AC side of the grid-connected inverter is The maximum value of the measured value at a fixed time interval; The total active power on the DC side of the grid-following inverter is The minimum value of the measurement value at a fixed time interval; The total active power on the AC side of the grid-following inverter is The maximum value of the measured value at a fixed time interval; The battery energy storage discharge power is The maximum value of the measured value at a fixed time interval.

3. The method for controlling transient power angle of a station with multiple grid-connected modes and photovoltaic standby participation according to claim 2, characterized in that: The DC side active power prediction value and AC side active power parameter prediction value of the grid-forming inverter and the grid-following inverter, as well as the battery energy storage discharge power parameter prediction value, are shown in the following formula (4): （4） in, The predicted value of the total active power on the DC side of the grid-connected inverter at each moment; The predicted value of the total active power on the AC side of the grid-connected inverter at any moment; Always follow the predicted value of the total active power on the DC side of the grid-connected inverter; Always keep up with the predicted value of the total active power on the AC side of the grid-connected inverter; The predicted value of battery energy storage discharge power at the moment.

4. The method for controlling transient power angle of a station with photovoltaic backup in multiple grid-connected modes according to claim 3, characterized in that: The corresponding normalized values ​​are shown in the following formula (5): （5） in, Normalized value of the total active power prediction value of the DC side of the grid-connected inverter at each moment; Normalized value of the total active power prediction value of the AC side of the grid-connected inverter at any moment; Normalized value of the total active power prediction value of the DC side of the grid-connected inverter at all times; Normalized value of the total active power prediction value of the AC side of the grid-connected inverter at all times; Normalized value of the battery energy storage discharge power prediction value at the moment.

5. The method for controlling transient power angle of a station with photovoltaic backup in multiple grid-connected modes according to claim 4, characterized in that: The predicted value of the station transient power angle index is shown in the following formula (6): （6） in, Indicates the predicted value of the station transient power angle index.

6. The method for controlling transient power angle of a station with multiple grid-connected modes and photovoltaic standby participation according to claim 5, characterized in that: Based on the transient power angle index prediction value, controlling the DC side active power parameters and AC side active power parameters of the grid-forming inverter and the grid-following inverter, and the discharge power parameters of the battery energy storage, including: If the transient power angle index prediction value is greater than or equal to a preset threshold, increasing the discharge power of the multi-grid-connected mode photovoltaic backup and station active power or battery energy storage; If the predicted value of the transient power angle index is less than the threshold, the discharge power of the grid-mode photovoltaic backup and the station active power or the battery energy storage is reduced.

7. The method for controlling transient power angle of a station with multiple grid-connected modes and photovoltaic standby participation according to claim 6, characterized in that: The preset threshold is 0.

43.

8. A transient power angle control device for a station with photovoltaic backup in multiple grid-connected modes, characterized in that: The station transient power angle control device uses the station transient power angle control method with multi-grid-connected mode photovoltaic standby participation according to any one of claims 1 to 7, and the station transient power angle control device includes: An acquisition module is provided for obtaining the DC side active power parameters and AC side active power parameters of the grid-connected inverter and the grid-following inverter of the photovoltaic standby participating station in the multi-grid mode, as well as the discharge power parameters of the battery energy storage, for determining the transient power angle index of the station; A time series module is configured to create time series of the DC side active power parameters and AC side active power parameters of the grid-connecting inverter and the grid-following inverter, as well as the discharge power parameters of the battery energy storage; An impact factor module, based on each of the time series, determines the impact factors of the DC side active power parameters and AC side active power parameters of the grid-connecting inverter and the grid-following inverter, and the discharge power parameter of the battery energy storage at the next moment; A first prediction module determines, based on the influencing factors, a predicted DC side active power parameter and an AC side active power parameter of each of the grid-connecting inverter and the grid-following inverter, as well as a predicted battery energy storage discharge power parameter at the next moment; A normalization module normalizes the DC side active power prediction value and the AC side active power parameter prediction value and the battery energy storage discharge power parameter prediction value of each of the grid-forming inverter and the grid-following inverter to obtain corresponding normalized values; A second prediction module determines, based on the normalized values, a predicted value of a transient power angle index of a station in which photovoltaic standby power is involved in a multi-grid connection mode at a next moment; A control module controls the DC side active power parameters and AC side active power parameters of the grid-forming inverter and the grid-following inverter, and the discharge power parameters of the battery energy storage, based on the transient power angle index prediction value.

9. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein: When the processor executes the program, the method for controlling transient power angle of a station with photovoltaic backup participation in multiple grid-connected modes as described in any one of claims 1 to 7 is implemented.

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