A Cooperative Regulation Method for Photovoltaic Charging Stations with Multiple Distribution Transformers Supplying Power

Abstract

The present invention proposes a collaborative regulation method for a photovoltaic charging station powered by multiple distribution transformers, belonging to the technical field of charging station load regulation. First, the data required for the collaborative regulation of the photovoltaic-charging station is obtained. Then, the current moment is selected. Based on the obtained data and with the current moment as the reference, the charging load of the distribution transformer at the next moment and the active power of the photovoltaic equipment at the next moment are predicted. On this basis, the load rates of multiple distribution transformers are calculated. Considering the risk of overload of the distribution transformers, the photovoltaic equipment in the charging station is regulated according to the real-time operation conditions of each distribution transformer in the station, and a regulation plan coordinated by two means, namely, photovoltaic grid connection point transfer and charging load reduction, is formulated. This solution does not use the method of optimizing the mathematical optimization model, greatly saving the operation calculation cost. Overall, the load conditions of multiple distribution transformers are considered, the comprehensive peak shaving benefit of the photovoltaic equipment for multiple distribution transformers is exerted, and the load states of multiple distribution transformers in the charging station are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of charging station load regulation, and more specifically, to a collaborative regulation method for a photovoltaic charging station powered by multiple distribution transformers. Background Art

[0002] Driven by the "dual carbon" policy and the construction of a new power system, as an environmentally friendly and efficient clean energy, while the grid-connected scale of photovoltaic power is continuously increasing, it also plays a peak shaving role for the power grid as a regulation resource. On the other hand, with the large-scale growth of electric vehicles, electric vehicle charging stations have shown a rapid development trend. The charging load with obvious peak-valley differences poses a non-negligible risk of heavy overload to power supply equipment. Therefore, by building photovoltaic power generation in charging stations to form a photovoltaic charging station operation mode, it will better play the role of photovoltaic in suppressing the impact of charging load and local consumption.

[0003] Large charging stations for electric buses and electric taxis are also the main sources of charging load in the current power system. There are cases of multi-distribution transformer power supply in such large charging station scenarios. Due to the non-simultaneity of charging loads, the maximum loads of different distribution transformers generally do not occur at the same time. Using photovoltaic for switching regulation is beneficial to improving the load conditions of each distribution transformer device and enhancing the peak shaving benefit of photovoltaic grid connection.

[0004] The prior art discloses a collaborative regulation method and system for a distribution network considering the access of electric vehicles. First, regional grid framework information, regional real-time load data, and historical load data are collected. Then, a regional load curve prediction model is constructed based on the regional real-time load data and historical load data. An optimal control model is constructed based on source-side photovoltaic regulation. According to the regional grid framework information, a power flow calculation topological grid is constructed. The predicted load value output by the regional load curve prediction model and the optimal regulation value output by the optimal control model are input into the power flow calculation topological framework, and finally, a collaborative regulation scheme for the distribution network is output. This scheme, based on a mathematical optimization method, considers the reasonable allocation of resources among charging piles, photovoltaics, and energy storage, and formulates real-time regulation schemes for photovoltaics and energy storage in charging stations. While maintaining economic benefits, it ensures the safety and reliability of the system. However, on the one hand, this scheme needs to establish a mathematical optimization model and perform optimization solutions, which has the problem of complex calculations and high requirements for the computing power of relevant terminal devices and the background. On the other hand, this scheme uniformly considers the load data of the distribution network and does not consider the load coordination control of multiple distribution transformers. Summary of the Invention

[0005] To solve the problems that when regulating the load of a charging station, the current method of establishing a mathematical optimization model and solving it has complex calculations, high requirements for equipment capabilities, and incomplete consideration of load coordinated control, the present invention proposes a collaborative regulation method for a photovoltaic charging station with multi-distribution transformer power supply, which does not involve a mathematical optimization algorithm, saves the operation calculation cost, and considers the charging loads of multiple distribution transformers, giving full play to the comprehensive peak shaving benefits of photovoltaics for multiple distribution transformers and improving the load status of the distribution transformers.

[0006] To achieve the above technical effects, the technical solution of the present invention is as follows:

[0007] A collaborative regulation method for a photovoltaic charging station with multi-distribution transformer power supply, the method comprising:

[0008] S1. Obtain data: including obtaining the equipment parameters of each distribution transformer of the charging station, the real-time operation data of the charging station equipment, and the historical operation data of the charging station equipment;

[0009] S2. Taking t as the real-time moment, based on the data obtained in S1, predict the charging load P of the i-th distribution transformer at the moment t + 1 i,t+1 , and the active power P of the photovoltaic equipment at the moment t + 1 PV,t+1 ;

[0010] S3. Based on the charging load P i,t+1 and the active power P of the photovoltaic equipment PV,t+1 , determine the load rate of the distribution transformer; on the basis of considering the load rate of the distribution transformer, formulate a regulation plan for reducing the load of the distribution transformer of the charging station and transferring the photovoltaic grid connection;

[0011] S4. Set a regulation period, wait for the change duration of ΔT based on the regulation period, and adjust the photovoltaic grid connection point and the charging load of the distribution transformer according to the regulation plan.

[0012] Preferably, in step S1, the equipment parameters of each distribution transformer of the charging station obtained include: the number of distribution transformers N of the charging station dis ; the capacity S of each distribution transformer i , where i ∈ 1 to N dis ; the power factor cosθ of each distribution transformer i , where i ∈ 1 to N dis .

[0013] Preferably, the real-time operation data of the charging station equipment includes: the active power P of the charging load of the i-th distribution transformer at the moment t i,t ; the active power output P of the photovoltaic equipment at the moment t PV,t ; the distribution transformer k accessed by the photovoltaic equipment at the moment t; the unit switching transfer cost c of the photovoltaic equipment PV,deal,t ; the compensation cost c for reducing the unit charging load EV,deal,t .

[0014] Preferably, the historical operation data of the charging station equipment includes: the charging load active power P of the i-th distribution transformer at the t-th time every day in the past week 7,i,t ,…,P 2,i,t , P 1,i,t ; The active power output P of the photovoltaic equipment of the charging station at the tth moment every day in the past week 7,PV,t ,…,P 2,PV,t , P 1,PV,t .

[0015] Preferably, in step S2, according to the charging load active power P of the i-th distribution transformer at the t-th time of each day in the past week, 7,i,t ,…,P 2,i,t , P 1,i,t and the charging load active power P of the i-th distribution transformer at the tth moment i,t , predict the charging load P of the i-th distribution transformer at time t+1 i,t+1 , the prediction expression satisfies:

[0016]

[0017] P i,t+1 =P i,t (1+η i.t ) (2)

[0018] Among them, η i.t is the predicted growth rate of the charging load active power of the i-th distribution transformer at the t-th moment;

[0019] According to the active power output P of the photovoltaic equipment at the tth moment of each day in the past week 7,PV,t ,…,P 2,PV,t , P 1,PV,t and the active power output P of the photovoltaic device at time t PV,t , predict the active power P of the photovoltaic equipment at time t+1 PV,t+1 , the prediction expression is:

[0020]

[0021] P PV,t+1 =P PV,t (1+η PV.t ) (4)

[0022] Among them, η PV.t It is the predicted growth rate of active power output of photovoltaic equipment at the tth moment.

[0023] Preferably, based on the charging load P i,t+1 and the active power P of the photovoltaic device PV,t+1 , the process of determining the load factor of the distribution transformer is:

[0024] According to the predicted charging load \(P_{i,t + 1}\) of each distribution transformer at the \((t + 1)\)-th moment, calculate the pure load rate \(\lambda\) of each distribution transformer at the \((t + 1)\)-th moment i,t+1 , and the calculation expression is:

[0025]

[0026] Sort the load rate \(\lambda\) i,t+1 in descending order. If there is a distribution transformer with a load rate that satisfies: \(\lambda\) i,t+1 > 100%, then include this distribution transformer \(j\) in the target set \(A\) of the equipment to be regulated, and enter the regulation plan for reducing the load of the distribution transformer in the charging station and transferring the photovoltaic grid connection; if there is no \(\lambda\) i,t+1 > 100%, then set that the grid connection point of the photovoltaic equipment does not transfer, and all distribution transformers do not need to reduce the charging load, and end the formulation of the regulation process.

[0027] Preferably, the process of formulating the regulation plan for reducing the load of the distribution transformer in the charging station and transferring the photovoltaic grid connection is as follows:

[0028] S31. Denote the serial number of the distribution transformer with the highest load rate \(\lambda\) i,t+1 as \(m\), and assume that the serial number of the distribution transformer where the photovoltaic equipment was originally connected to the grid is \(k\). If \(m = k\), then set that the grid connection point of the photovoltaic equipment does not transfer, and calculate the reduction of the charging load \(P\) j,DT,t+1 for all overloaded distribution transformers in the target set \(A\) of the controlled equipment. The expression is:

[0029]

[0030] Then, end the formulation of the regulation plan; if \(m\neq k\), then execute step S32;

[0031] S32. Evaluate the comprehensive regulation costs of the distribution transformer \(m\) and the distribution transformer \(k\) in two cases: when the photovoltaic grid connection is transferred to the distribution transformer \(m\) and when the grid connection point does not transfer to the distribution transformer \(m\), and denote them as \(C1\) and \(C2\) respectively;

[0032] S33. By comparing the magnitudes of \(C1\) and \(C2\), formulate the regulation plan for reducing the load of the distribution transformer in the charging station and transferring the photovoltaic grid connection. The process satisfies:

[0033] If \(C1 < C2\), then set that the grid connection point of the photovoltaic equipment is transferred from the distribution transformer \(k\) to the distribution transformer \(m\), and all overloaded distribution transformers in the target set \(A\) of the controlled equipment obtain the reduction of the charging load \(P\) j,DT,t+1 according to formula (6);

[0034] If \(C1\geq C2\), then set that the grid connection point of the photovoltaic equipment remains unchanged, and all overloaded distribution transformers in the target set \(A\) of the controlled equipment obtain the reduction of the charging load \(P\) j,DT,t+1 according to formula (7):

[0035]

[0036] S34. End the formulation of the regulation plan.

[0037] In the above technical solution, considering the risk of overload of the distribution transformer, the photovoltaic equipment in the charging station is regulated according to the real-time operation conditions of each distribution transformer in the station. According to the operation risk and regulation cost, a regulation plan coordinated by two means of photovoltaic connection point transfer and charging load reduction is formulated to meet the requirements of grid safe operation and take into account the photovoltaic grid connection and consumption. It is not carried out in the way of optimizing the mathematical optimization model, which greatly saves the operation calculation cost. Overall, the load conditions of multiple distribution transformers are considered, and the comprehensive peak shaving benefit of photovoltaic equipment for multiple distribution transformers is exerted, improving the load status of multiple distribution transformers in the charging station.

[0038] Preferably, in step 32, the calculation process of C1 satisfies:

[0039] 1) If k belongs to A, then:

[0040]

[0041] 2) If k does not belong to A, then:

[0042]

[0043] Preferably, in step S32, the calculation process of C2 satisfies:

[0044] 1) If k belongs to A, then:

[0045]

[0046] 2) If k does not belong to A, then:

[0047] C2 = c EV,deal,t+1 (P m,t+1 -S m cosθ m ) (11).

[0048] Preferably, after S4, it further includes: returning to step S2 and continuing to execute the regulation of the next round of photovoltaic connection point and distribution transformer charging load.

[0049] Compared with the prior art, the beneficial effects of the technical solution of the present invention are:

[0050] The present invention proposes a collaborative regulation method for a photovoltaic charging station powered by multiple distribution transformers. First, the data required for the collaborative regulation of the photovoltaic-charging station is obtained. Then, the current moment is selected. Based on the obtained data and with the current moment as the reference, the charging load of the distribution transformer at the next moment and the active power of the photovoltaic equipment at the next moment are predicted. On this basis, the load rates of multiple distribution transformers are calculated. Considering the risk of overload of the distribution transformer, the photovoltaic equipment in the charging station is regulated according to the real-time operation conditions of each distribution transformer in the station, and a regulation plan coordinated by two means, namely, the transfer of the photovoltaic grid connection point and the reduction of the charging load, is formulated. This solution does not use the optimization method of the mathematical optimization model, greatly saving the operation calculation cost. Overall, the load conditions of multiple distribution transformers are considered, the comprehensive peak shaving benefit of the photovoltaic equipment for multiple distribution transformers is exerted, and the load states of multiple distribution transformers in the charging station are improved. Description of the Drawings

[0051] Figure 1 It shows the flow chart of the collaborative regulation method for a photovoltaic charging station powered by multiple distribution transformers proposed in Embodiment 1 of the present invention;

[0052] Figure 2 It shows the time series characteristic curve of the active power of the predicted charging load for 3 distribution transformers proposed in Embodiment 3 of the present invention;

[0053] Figure 3 It shows the characteristic curve of the predicted active power output of the photovoltaic equipment in the charging station proposed in Embodiment 3 of the present invention; Detailed Embodiment

[0054] The drawings are only for illustrative purposes and cannot be construed as a limitation of this patent;

[0055] For better illustration of this embodiment, some parts of the drawings are omitted, enlarged or reduced, and do not represent the actual size;

[0056] For those skilled in the art, it is understandable that some well-known content descriptions in the drawings may be omitted.

[0057] The technical solution of the present invention will be further described below with reference to the drawings and embodiments.

[0058] The description of the positional relationship in the drawings is only for illustrative purposes and cannot be construed as a limitation of this patent;

[0059] Embodiment 1

[0060] This embodiment proposes a collaborative regulation method for a photovoltaic charging station powered by multiple distribution transformers. The flow chart of this method can be seen in Figure 1 , and specifically includes:

[0061] S1. Obtain data: including obtaining the equipment parameters of each distribution transformer in the charging station, the real-time operation data of the charging station equipment, and the historical operation data of the charging station equipment;

[0062] In this embodiment, the device parameters of each distribution transformer in the charging station include: the number of distribution transformers N in the charging station dis ; the capacity S of each distribution transformer i , where i ∈ 1 to N dis ; the power factor cosθ of each distribution transformer i , where i ∈ 1 to N dis .

[0063] The real-time operation data of the charging station equipment includes: the active power P of the charging load at the t-th moment of the i-th distribution transformer i,t ; the active power output P of the photovoltaic equipment at the t-th moment PV,t ; the distribution transformer k accessed by the photovoltaic equipment at the t-th moment; the unit switching transfer cost c of the photovoltaic equipment PV,deal,t ; the compensation cost c for reducing the unit charging load EV,deal,t .

[0064] The historical operation data of the charging station equipment includes: the active power P of the charging load at the t-th moment of each day in the past week of the i-th distribution transformer 7,i,t ,..., P 2,i,t , P 1,i,t ; the active power output P of the charging station photovoltaic equipment at the t-th moment of each day in the past week 7,PV,t ,..., P 2,PV,t , P 1,PV,t .

[0065] S2. Taking t as the real-time moment, based on the data obtained in S1, predict the charging load P of the i-th distribution transformer at the t+1 moment i,t+1 , and the active power P of the photovoltaic equipment at the t+1 moment PV,t+1 ;

[0066] S3. Based on the charging load P i,t+1 and the active power P of the photovoltaic equipment PV,t+1 , determine the load rate of the distribution transformer; on the basis of considering the load rate of the distribution transformer, formulate a regulation plan for reducing the load of the distribution transformer in the charging station and transferring the photovoltaic grid connection;

[0067] S4. Set the regulation period, wait for the change duration of ΔT based on the regulation period, and adjust the photovoltaic grid connection point and the charging load of the distribution transformer according to the regulation plan.

[0068] In this embodiment, the data required for the coordinated regulation of the photovoltaic-charging station is first obtained, and then the current moment is selected. Based on the obtained data and with the current moment as the reference, the charging load of the distribution transformer at the next moment and the active power of the photovoltaic equipment at the next moment are predicted. On this basis, the load rates of multiple distribution transformers are calculated. Considering the risk of overload of the distribution transformer, the photovoltaic equipment in the charging station is regulated according to the real-time operation conditions of each distribution transformer in the station, and a regulation plan coordinated by two means, namely, the transfer of the photovoltaic connection point and the reduction of the charging load, is formulated. This solution does not adopt the method of optimizing the membrane performance by mathematics, which greatly saves the operation calculation cost. Overall, the load conditions of multiple distribution transformers are considered, and the comprehensive peak shaving benefit of the photovoltaic equipment for multiple distribution transformers is exerted, improving the load status of multiple distribution transformers in the charging station.

[0069] Embodiment 2

[0070] This embodiment describes the specific process of formulating a regulation plan for reducing the load of the distribution transformer in the charging station and transferring the photovoltaic grid connection. First, according to the active power P of the charging load at the t-th moment of each day in the past week of the i-th distribution transformer 7,i,t 、…、P 2,i,t 、P 1,i,t and the active power P of the charging load at the t-th moment of the i-th distribution transformer i,t , the charging load P of the i-th distribution transformer at the t+1-th moment is predicted i,t+1 , and the prediction expression satisfies:

[0071]

[0072] P i,t+1 =P i,t (1+η i.t ) (2)

[0073] Among them, η i.t is the predicted growth rate of the active power of the charging load at the t-th moment of the i-th distribution transformer;

[0074] According to the active power output P of the photovoltaic equipment at the t-th moment of each day in the past week 7,PV,t 、…、P 2,PV,t 、P 1,PV,t and the active power output P of the photovoltaic equipment at the t-th moment PV,t , the active power P of the photovoltaic equipment at the t+1-th moment is predicted PV,t+1 , and the prediction expression is:

[0075]

[0076] P PV,t+1 =P PV,t (1+η PV.t ) (4)

[0077] Among them, η PV.tIt is the predicted growth rate of the active power output of the photovoltaic device at the t-th moment.

[0078] Then, based on the charging load P i,t+1 and the active power P PV,t+1 of the photovoltaic device, determine the load rate of the distribution transformer. The process is as follows:

[0079] According to the predicted charging load Pi,t+1 of each distribution transformer at the (t + 1)-th moment, calculate the pure load rate λ i,t+1 of each distribution transformer at the (t + 1)-th moment. The calculation expression is:

[0080]

[0081] Sort the load rate λ i,t+1 in descending order. If there is a distribution transformer with a load rate that satisfies: λ i,t+1 > 100%, then include this distribution transformer j in the target set A of the equipment to be regulated and enter the regulation plan for reducing the load of the distribution transformer in the charging station and transferring the photovoltaic grid connection; if there is no λ i,t+1 > 100%, then set that the grid connection point of the photovoltaic device does not transfer, and all distribution transformers do not need to reduce the charging load, and end the formulation of the regulation process.

[0082] On the basis of considering the load rate of the distribution transformer, formulate the regulation plan for reducing the load of the distribution transformer in the charging station and transferring the photovoltaic grid connection. The process of formulating the regulation plan for reducing the load of the distribution transformer in the charging station and transferring the photovoltaic grid connection is as follows:

[0083] S31. Denote the serial number of the distribution transformer with the highest load rate λ i,t+1 as m. Assume that the original grid connection of the photovoltaic device is at the serial number k of the distribution transformer. If m = k, then set that the grid connection point of the photovoltaic device does not transfer, and calculate the reduction of the charging load P j,DT,t+1 for all overloaded distribution transformers in the target set A of the controlled equipment. The expression is:

[0084]

[0085] Then, end the formulation of the regulation plan; if m ≠ k, then execute step S32;

[0086] S32. Evaluate the comprehensive regulation costs of the distribution transformer m and the distribution transformer k in the two cases of transferring the photovoltaic grid connection to the distribution transformer m and not transferring the grid connection point to the distribution transformer m, and denote them as C1 and C2 respectively;

[0087] S33. By comparing the magnitudes of C1 and C2, formulate the regulation plan for reducing the load of the distribution transformer in the charging station and transferring the photovoltaic grid connection. The process satisfies:

[0088] If C1 < C2, then set that the grid connection point of the photovoltaic device is transferred from the distribution transformer k to the distribution transformer m, and all overloaded distribution transformers in the target set A of the controlled equipment obtain the reduction of the charging load P j,DT,t+1;

[0089] If C1≥C2, then set the grid connection point of the photovoltaic device to remain unchanged, and the charging load reduction magnitude P of all overloaded distribution transformers in the regulation device target set A is obtained according to Equation (7). j,DT,t+1 :

[0090]

[0091] S34. End the formulation of the regulation plan.

[0092] The calculation process of C1 satisfies:

[0093] 1) If k belongs to A, then:

[0094]

[0095] 2) If k does not belong to A, then:

[0096]

[0097] Preferably, in step S32, the calculation process of C2 satisfies:

[0098] 1) If k belongs to A, then:

[0099]

[0100] 2) If k does not belong to A, then:

[0101] C2 = c EV,deal,t+1 (P m,t+1 -S m cosθ m ) (11).

[0102] Finally, after S4, it further includes: returning to step S2 and continuing to perform the next round of regulation of the photovoltaic grid connection point and the distribution transformer charging load.

[0103] Embodiment 3

[0104] This embodiment takes the method proposed by the present invention as a means and takes a photovoltaic charging station powered by multiple distribution transformers as an example for simulation calculation. In this embodiment, the regulation period T is 15 minutes, and the number of distribution transformers N in the charging station dis is 3, the capacity S of each distribution transformer i is 500 kVA, and the power factor cosθ of each distribution transformer i is 0.95. The predicted load characteristic curves of the 3 distribution transformers are as Figure 2 shown, and the predicted output characteristic curve of the photovoltaic device is as Figure 3 shown. The serial number of the distribution transformer connected by the photovoltaic device at the initial moment t = 0 is 1, and the unit switching transfer cost c of the photovoltaic device PV,deal,tIt is 100 yuan per time, reducing the compensation cost c of the unit charging load EV,deal,t It is 1 yuan / kW.

[0105] As can be seen from the example settings, when the time is 12:00, it is predicted that the pure load rate of distribution transformer 3 at the next moment 12:15 reaches 137.3%, exceeding 100% and thus being in an overloaded state. Distribution transformer 3 is included in the target set A of the equipment to be regulated. Since the photovoltaic equipment was originally connected to distribution transformer 1, that is, m≠k, it is necessary to evaluate the comprehensive regulation costs of distribution transformer 3 and distribution transformer 1 in two cases: when the photovoltaic grid connection is transferred to distribution transformer 3 and when the grid connection point is not transferred to distribution transformer 3. According to step (6-4), the costs C1 and C2 for the photovoltaic grid connection to be transferred to distribution transformer 3 are 132.23 yuan and 211.60 yuan respectively, that is, C1 < C2. Set the grid connection point of the photovoltaic equipment to be transferred from distribution transformer 1 to distribution transformer 3, and reduce the magnitude P of the charging load at the next moment j,DT,t+1 It is 32.23 kW. Thus, the regulation plan for the moment of 12:15 is formulated. After waiting for 15 minutes, adjust the photovoltaic grid connection point to be transferred to distribution transformer 3 according to the regulation plan, and reduce the charging load of distribution transformer 3 by 32.23 kW.

[0106] The embodiments are only examples for clearly illustrating the present invention, and are not intended to limit the implementation manners of the present invention. For those of ordinary skill in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation manners here. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention shall be included within the protection scope of the claims of the present invention.

Claims

1. A collaborative control method for a photovoltaic charging station powered by multiple distribution transformers, characterized in that, The method includes: S1. Obtain data: including obtaining the device parameters of each distribution transformer in the charging station, the real-time operation data of the charging station equipment, and the historical operation data of the charging station equipment; S2. Taking t as the real-time moment, based on the data obtained in S1, predict the charging load Pi of the i-th distribution transformer at the moment t + 1 i,t+1 , and the active power Ppv of the photovoltaic device at the moment t + 1 PV,t+1 ; In step S2, according to the active power P of the charging load at the t-th moment of each day in the recent week of the i-th distribution transformer 7,i,t , …, P 2,i,t , P 1,i,t and the active power P of the charging load at the t-th moment of the i-th distribution transformer i,t , predict the charging load P of the i-th distribution transformer at the (t + 1)-th moment i,t+1 , and the prediction expression satisfies: P i,t+1 = P i,t (1 + η i.t )(2) Among them, η i.t is the predicted growth rate of the active power of the charging load at the t-th moment of the i-th distribution transformer; According to the active power output $P$ of the photovoltaic device at the $t$-th moment of each day in the past week 7,PV,t ,..., $P$ 2,PV,t , $P$ 1,PV,t and the active power output $P$ of the photovoltaic device at the $t$-th moment PV,t , predict the active power $P$ of the photovoltaic device at the $(t + 1)$-th moment PV,t+1 , and the prediction expression is: P PV,t+1 = P PV,t (1 + η PV.t ) (4) Among them, η PV.t is the predicted growth rate of the active power output of the photovoltaic device at the t-th moment; S3. Based on the charging load P i,t+1 and the active power P PV,t+1 of the photovoltaic device, determine the load rate of the distribution transformer; on the basis of considering the load rate of the distribution transformer, formulate a regulation plan for load reduction of the distribution transformer of the charging station and photovoltaic grid-connected transfer; Based on the charging load P i,t+1 and the active power P of the photovoltaic device PV,t+1 , the process of determining the load rate of the distribution transformer is as follows: According to the predicted charging load \(P\) of each distribution transformer at the \((t + 1)\)-th moment i,t+1 , calculate the pure load rate \(\lambda\) of each distribution transformer at the \((t + 1)\)-th moment i,t+1 , and the calculation expression is as follows: Sort the load factor λ i,t+1 in descending order. If there is a load factor of a distribution transformer that satisfies: λ i,t+1 > 100%, then include this distribution transformer j in the target set A of the equipment to be regulated and enter the regulation plan for load reduction of the distribution transformer in the charging station and transfer of photovoltaic grid connection; if there is no λ i,t+1 > 100%, then set that the grid connection point of the photovoltaic equipment does not transfer, and all distribution transformers do not need to reduce the charging load, and end the formulation of the regulation process; The process of formulating a regulation plan for reducing the load of the distribution transformer in the charging station and transferring the PV grid connection is as follows: S31. Record the load rate λ i,t+1 The highest distribution transformer serial number is m. Suppose the original grid - connection serial number of the photovoltaic device to the distribution transformer is k. If m = k, then set that the grid - connection point of the photovoltaic device does not transfer, and calculate and reduce the charging load P of all overloaded distribution transformers in the target set A of the control device; j,DT,t+1 Then, end the formulation of the control plan. If m ≠ k, then execute step S32; S32. Evaluate the comprehensive regulation costs of distribution transformer m and distribution transformer k in two cases: when the PV grid connection is transferred to distribution transformer m and when the grid connection point is not transferred to distribution transformer m, denoted as C1 and C2 respectively; S33. By comparing the magnitudes of C1 and C2, formulate a regulation plan for reducing the load of the distribution transformer in the charging station and transferring the PV grid connection; S34. End the formulation of the regulation plan; S4. Set a regulation period, wait for the change duration of ΔT based on the regulation period, and adjust the charging loads of the PV grid connection point and the distribution transformer according to the regulation plan.

2. The collaborative regulation method of the photovoltaic charging station with multi-transformer power supply according to claim 1, characterized in that In step S1, the device parameters of each distribution transformer of the charging station include: the number of distribution transformers N of the charging station dis ; the capacity S of each distribution transformer i , where i ∈ 1 to N dis ; the power factor cosθ of each distribution transformer i , where i ∈ 1 to N dis .

3. The collaborative regulation method of the photovoltaic charging station with multiple distribution transformers power supply according to claim 2, wherein, The real-time operation data of the charging station equipment includes: the active power P of the charging load at the t-th moment of the i-th distribution transformer i,t ; the active power output P of the photovoltaic equipment at the t-th moment PV,t ; the distribution transformer k accessed by the photovoltaic equipment at the t-th moment; the unit switching transfer cost c of the photovoltaic equipment PV,deal,t ; the compensation cost c for reducing the unit charging load EV,deal,t .

4. The collaborative regulation method of a photovoltaic charging station with multiple distribution transformers for power supply according to claim 3, characterized in that, The historical operation data of the charging station equipment includes: the active power P of the charging load at the t-th moment of each day in the past week for the i-th distribution transformer 7,i,t ,..., P 2,i,t , P 1,i,t ; the active power output P of the charging station's photovoltaic equipment at the t-th moment of each day in the past week 7,PV,t ,..., P 2,PV,t , P 1,PV,t .

5. The collaborative regulation method of a photovoltaic charging station with multiple power conversions and power supplies according to any one of claims 1 to 4, characterized in that The expression satisfied by step S31 is: The process of comparing the magnitudes of C1 and C2 in step S33 and formulating a regulation plan for reducing the load of the distribution transformer in the charging station and transferring the PV grid connection satisfies: If C1 < C2, set the grid connection point of the photovoltaic device to transfer from distribution transformer k to distribution transformer m, and all overloaded distribution transformers in the target set A of the control device obtain the reduced charging load magnitude P according to Equation (6). j,DT,t+1 ; If C1 ≥ C2, set the grid connection point of the photovoltaic device to remain unchanged, and obtain the magnitude P of the reduced charging load for all overloaded distribution transformers in the target set A of the control device according to Equation (7). j,DT,t+1 :

6. The collaborative regulation method of the photovoltaic charging station with multi-distribution transformer power supply according to claim 5, characterized in that, In step 32, the calculation process of C1 satisfies: 1) If k belongs to A, then: 2) If k does not belong to A, then:

7. The collaborative regulation method of the photovoltaic charging station with multiple distribution transformers power supply according to claim 6, wherein, In step S32, the calculation process of C2 satisfies: 1) If k belongs to A, then: 2) If k does not belong to A, then: C2 = c EV,deal,t+1 (P m,t+1 -S m cosθ m ) (11).

8. The collaborative regulation method of the photovoltaic charging station with multiple distribution transformers power supply according to claim 1, characterized in that, After S4, it further includes: returning to step S2 and continuing to execute the next round of regulation of the charging loads of the PV grid connection point and the distribution transformer.

Images