Charging control method and system for transformer area power transformation and distribution network

Abstract

The invention belongs to the technical field of charging control, and particularly relates to a transformer area power transformation and distribution network charging control method and system. The method comprises the following steps: acquiring a real-time electrical load and an average electrical load of a transformer in a zone area in a current time period, and determining a load state grade of the transformer in the zone area based on the real-time electrical load and the average electrical load of the transformer in the current time period and a rated power of the transformer in the zone area; calculating the available power allocated to the charging equipment under the corresponding load state level, and calculating the maximum output power of each charging equipment in the next time period according to the available power allocated to the charging equipment and the number of the charging equipment in the charging state in the transformer area in the current time period; and in the next time period, each charging device in the charging state is controlled to output power by taking the maximum output power of the charging device as a limit value, so that the calculation error and the requirements on the reliability and the calculation capability of the charging management platform are reduced.

Description

Technical Field

[0001] The present invention belongs to the technical field of charging control, and in particular relates to a charging control method and system for a transformer substation distribution network. Background Art

[0002] With the rapid promotion and application of electric vehicles, a large number of charging devices have been connected to the distribution network. The disorderly charging behavior of electric vehicles has brought a great impact on the distribution network system. In order to solve this problem, the main technical solution is to add a dedicated transformer on the distribution side of the substation substation system, and connect the charging equipment to the dedicated transformer to obtain charging power. The charging equipment is connected to the cloud charging management platform through 4G, WiFi or Ethernet and other communication methods. Figure 1 In actual operation, the charging management platform automatically collects the actual output power of the charging equipment during operation, and automatically generates a power adjustment parameter model based on the transformer nameplate parameters, the charging equipment nameplate parameters and the power limit model set by the platform. The maximum output power limit of the charging equipment is calculated based on the power adjustment parameter model, and then the maximum output power limit modification command of the charging equipment is sent to all charging equipment connected to the platform for execution. The process is as follows: Figure 2 This solution is highly dependent on the charging management platform and is greatly affected by the platform reliability, computing power, and parameter adjustment model. It is prone to errors and the calculation is relatively complex, which places high requirements on the management platform. Summary of the invention

[0003] The object of the present invention is to provide a charging control method and system for a transformer substation distribution network, so as to solve the problem that the existing transformer substation distribution network charging control method is prone to errors and has relatively complex calculations.

[0004] In order to solve the above technical problems, the present invention provides a charging control method for a transformer substation, comprising:

[0005] Obtain the real-time power load and average power load of the transformer in the current time period, and determine the load state level of the transformer in the area based on the real-time power load, average power load and rated power of the transformer in the current time period; the real-time power load of the transformer in the area refers to the real-time power load for non-charging equipment within the area;

[0006] Calculate the available power allocated to the charging equipment under the corresponding load state level, and calculate the maximum output power of each charging equipment in the next time period based on the available power allocated to the charging equipment and the number of charging equipment in the area in the current time period;

[0007] In the next time period, each charging device in the charging state is controlled to output power with the maximum output power of the charging device as the limit value.

[0008] Furthermore, the load status levels include Load Status Level 1, Load Status Level 2, Load Status Level 3, and Load Status Level 4. The method for determining the load status level of the substation area transformer is as follows: If P1 < P and P1' < P, the substation area transformer is in Load Status Level 1; if P1 > P and P1' < P, the substation area transformer is in Load Status Level 2; if P1 < P and P1' > P, the substation area transformer is in Load Status Level 3; if P1 > P and P1' > P, the substation area transformer is in Load Status Level 4. Wherein, P1 is the real-time power consumption load of the substation area transformer in the current time period, P1' is the average power consumption load of the substation area transformer in the current time period, and P is the rated power of the substation area transformer.

[0009] Furthermore, when the substation area transformer is in Load Status Level 1, the available power allocated to the charging equipment is calculated based on the rated power of the substation area transformer and the average power consumption load of the substation area transformer in the current time period. The calculation formula is:

[0010]

[0011] Wherein, is the available power allocated to the charging equipment.

[0012] Furthermore, when the substation area transformer is in Load Status Level 2, the available power allocated to the charging equipment is calculated based on the rated power of the substation area transformer, the reserved safety margin, and the average power consumption load of the substation area transformer in the current time period. The calculation formula is:

[0013]

[0014] Wherein, ΔP is the reserved safety margin of the substation area transformer.

[0015] Furthermore, when the substation area transformer is in Load Status Level 3, the available power allocated to the charging equipment is calculated based on the rated power of the substation area transformer, the average power consumption load of the substation area transformer in the current time period, and the average output power of all charging equipment connected to the substation area power distribution system in the current time period. The calculation formula is:

[0016]

[0017] Wherein, P2' is the average output power of all charging equipment connected to the substation area power distribution system in the current time period.

[0018] Furthermore, when the transformer in the substation is in load state level 4, the available power allocated to the charging equipment is calculated based on the rated power and reserved safety margin of the transformer in the substation, the average power load of the transformer in the substation in the current time period, and the average output power of all charging equipment connected to the substation power distribution system in the current time period. The calculation formula is:

[0019]

[0020] Among them, P2' is the average output power of all charging devices connected to the substation substation distribution system in the current time period.

[0021] Furthermore, the available power allocated to the charging devices is calculated and distributed in an average distribution manner to obtain the maximum output power of each charging device in the next time period.

[0022] Furthermore, if a new charging device enters the charging state within the next time period, the new charging device is controlled to output with the offline default maximum output power as the limit; wherein, the offline default maximum output power is calculated based on the rated power of the substation transformer, the average power load of the substation transformer corresponding to the time period, and the total number of charging devices connected to the substation substation system.

[0023] The beneficial effects of the above technical solution are as follows: the present invention is a pioneering invention, which first performs real-time detection of the power load on the substation side and evaluates the working status of the substation power distribution system, that is, determines the load state level of the substation transformer according to the real-time power load, average power load and rated power of the substation transformer in the current time period, and calculates the available power allocated to the charging equipment under the corresponding load state level according to the load state level of the transformer in the current time period, and then determines the maximum output power of the charging equipment in the charging state in the next time period according to the available power allocated to the charging equipment. The calculation method is simple when determining the charging strategy, and there is no need to use a parameter adjustment model. There is no need to use a platform with high calculation accuracy and high calculation complexity to realize the charging control of the charging equipment by the substation power distribution system, which reduces the calculation error and the requirements for the reliability and computing power of the charging management platform.

[0024] In order to solve the above technical problems, the present invention also provides a substation substation distribution network charging control system, including a substation energy control unit, which is arranged in the substation substation distribution system and is used to execute computer program instructions to implement the steps in the substation substation distribution network charging control method introduced above.

[0025] Furthermore, the substation energy control unit communicates with the charging equipment connected to the substation through power carrier communication, RS485 communication or CAN bus communication.

[0026] The beneficial effects of the above technical solution are as follows: the present invention is a pioneering invention, which only requires the installation of an area energy control unit on the area power transformation and distribution system. The area energy control unit first performs real-time detection of the power load on the area side and evaluates the working status of the area power distribution system, that is, the load state level of the area transformer is determined according to the real-time power load, average power load and rated power of the area transformer in the current time period, and the available power allocated to the charging equipment under the corresponding load state level is calculated according to the load state level of the transformer in the current time period. The maximum output power of the charging equipment in the charging state in the next time period can be determined according to the available power allocated to the charging equipment. The calculation method is simple when determining the charging strategy, and there is no need to use a parameter adjustment model. There is no need to use a platform with high calculation accuracy and high calculation complexity to realize the charging control of the charging equipment by the area power transformation and distribution system, which reduces the calculation error and the requirements for the reliability and computing power of the charging management platform, and realizes the on-site control of the charging equipment within the area, and the management is more convenient and simple. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a schematic diagram of a charging management control system in the prior art;

[0028] Figure 2 It is a schematic diagram of the output power limit configuration of the charging equipment by the charging management platform in the prior art;

[0029] Figure 3 is a system schematic diagram of an embodiment of the system of the present invention;

[0030] Figure 4 It is a charging control flow chart of the substation substation distribution network in an embodiment of the system of the present invention. DETAILED DESCRIPTION

[0031] In order to make the purpose, technical solutions and advantages of the present invention more clear, the specific implementation methods of the present invention are further described below in conjunction with the accompanying drawings.

[0032] The present invention only requires the installation of an area energy control unit for the area power transformation and distribution system. The area energy control unit first performs real-time detection of the power load on the area side and evaluates the working status of the area power distribution system, that is, the load state level of the area transformer is determined according to the real-time power load, average power load and rated power of the area transformer in the current time period, and the available power allocated to the charging equipment under the corresponding load state level is calculated according to the load state level of the transformer in the current time period. The maximum output power of the charging equipment in the charging state in the next time period can be determined according to the available power allocated to the charging equipment. The calculation method is simple when determining the charging strategy, and there is no need to use a parameter adjustment model. There is no need to use a platform with high calculation accuracy and high calculation complexity to realize the charging control of the charging equipment by the area power transformation and distribution system, which reduces the calculation error and the requirements for the reliability and computing power of the charging management platform, and realizes the on-site control of the charging equipment within the area, and the management is more convenient and simple.

[0033] System Example

[0034] A charging control system for a transformer substation network of the present invention, such as Figure 3 As shown: it includes a substation energy control unit, which is set in the substation power distribution system, used to detect the power load on the substation side in real time and evaluate the load state of the substation power distribution system; and communicate with the electric vehicle charging equipment connected within the substation area, calculate the real-time output power of the charging equipment within the substation area, and evaluate the load state of the charging equipment within the substation area; according to the load state of the substation power distribution system and the load state of the charging equipment within the substation area, formulate a new charging control strategy, and send the control strategy to the charging equipment within the substation area for execution, so as to realize a substation power distribution network charging control method, thereby realizing intelligent charging control of charging equipment on the basis of ensuring the basic electricity consumption of residents, ensuring the power consumption safety of the substation power distribution system, and at the same time, the working state and parameters of the distribution network system and the working state and parameters of the charging equipment are used as the parameter source of system management to form a closed-loop control, which has higher reliability and safety, and ensures that the substation power distribution system is in a safe and reliable working state. The substation energy control unit can communicate with the charging equipment connected to the substation area through 4G, WiFi, Ethernet and other methods. Furthermore, in order to avoid the situation where the charging device cannot be controlled when the network is offline, the substation energy control unit communicates with the charging device connected to the substation through power carrier communication, RS485 communication or CAN bus communication. Preferably, in order to reduce costs, in this embodiment, the substation energy control unit communicates bidirectionally with the charging device through power carrier communication.

[0035] The specific process of the charging control method of the transformer substation is as follows: Figure 4 As shown, the following steps are included:

[0036] 1. The rated power P of the substation transformer in the substation power distribution system, the reserved safety margin ΔP, and the time slice parameter t (i.e., the time period) of the substation energy control unit have been default set.

[0037] The control scheme of the present invention is updated according to the time period, and the time period can be set according to actual needs. For example, the time period is set to 2 min, 5 min, 10 min, 15 min, etc. The time period of the present invention is set to 5 min, and the substation energy control unit divides 24 h into each 5 min / time slice, a total of 288 time slices are divided, and the charging control strategy is updated every 5 min. The charging control strategy can be sent to the charging device in the form of a charging parameter configuration file. At this time, the time period represents the effective duration of the charging parameter configuration file.

[0038] 2. Obtain the real-time power consumption load and average power consumption load of the substation transformer within the current time period.

[0039] The substation energy control unit of the present invention is equipped with 3 current sampling modules. The current sampling module is a current transformer. The substation energy control unit samples the output current of each phase of the substation transformer in real time through the circuit transformer, calculates the real-time power consumption load P1 of the substation transformer within the current time period, and calculates the average power consumption load P1' of the substation transformer within the current corresponding time period based on the real-time power consumption load. The real-time power consumption load of the substation transformer refers to the real-time power consumption load of non-charging devices within the scope of the substation, such as the real-time power consumption load for ensuring the basic electricity consumption of residents in the substation.

[0040] 3. Determine the load status level of the substation transformer within the current time period.

[0041] Based on the real-time power consumption load, average power consumption load of the substation transformer within the current time period and the rated power of the substation transformer, determine the load status level of the substation transformer. Specifically, the load status levels include load status level one, load status level two, load status level three, and load status level four; the method for determining the load status level of the substation transformer is: if P1 < P and P1' < P, the substation transformer is in load status level one; if P1 > P and P1' < P, the substation transformer is in load status level two; if P1 < P and P1' > P, the substation transformer is in load status level three; if P1 > P and P1' > P, the substation transformer is in load status level four.

[0042] 4. Determine the number M of devices in the charging state in the substation within the current time period and the average output power of all charging devices connected to the substation.

[0043] The substation energy control unit collects the real-time charging information of the charging devices connected to the substation power distribution system in the current time period through carrier communication, determines the number M of charging devices in the charging state, and calculates the real-time output power P2 and average output power P2' of all charging devices connected to the substation power distribution system in the current time period.

[0044] 5. Calculate the available power allocated to the charging equipment under the corresponding load status level, and calculate the maximum output power of the charging equipment in the next time period based on the available power allocated to the charging equipment and the number of charging equipment in the charging state in the station area in the current time period.

[0045] When the transformer in the substation is in load state level 1, the available power allocated to the charging equipment is calculated based on the rated power of the transformer in the substation and the average power load of the transformer in the current time period. The calculation formula is:

[0046]

[0047] When the transformer in the substation is in load state level 2, the available power allocated to the charging equipment is calculated based on the rated power of the transformer in the substation, the reserved safety margin and the average power load of the transformer in the current time period. The calculation formula is:

[0048]

[0049] When the transformer in the substation is in load state level three, the available power allocated to the charging equipment is calculated based on the rated power of the transformer in the substation, the average power load of the transformer in the substation in the current time period, and the average output power of all charging equipment connected to the substation in the current time period. The calculation formula is:

[0050]

[0051] When the transformer in the substation is in load state level 4, the available power allocated to the charging equipment is calculated based on the rated power and reserved safety margin of the transformer in the substation, the average power load of the transformer in the current time period, and the average output power of all charging equipment connected to the substation in the current time period. The calculation formula is:

[0052]

[0053] in, To allocate available power to charging equipment.

[0054] The present invention uses an average distribution method to distribute and calculate the available power allocated to the charging device to obtain the maximum output power of the charging device in the next time period. The calculation formula for the maximum output power Pout of each charging device in the next time period is:

[0055]

[0056] 6. In the next time period, each charging device in the charging state is controlled to output power with the maximum output power of the charging device as the limit.

[0057] In a time period, P1', P2' and M corresponding to each moment will be obtained according to the real-time P1 and P2, that is, multiple Pouts will be obtained in a time period, that is, when it is sent to the charging device in the form of a charging parameter configuration file for charging control, the charging parameter configuration file in the time period will be updated multiple times. The Pout calculated at a certain moment in the middle of the current time period or the Pout obtained by averaging multiple moments can be used for charging control. Preferably, in order to improve the control accuracy, the M value, P1' and P2' calculated at the end of the current time period, that is, the last moment of the current time period, are used as the parameter basis for formulating the charging strategy in the next time period, that is, the Pout calculated at the last moment of the current time period is the maximum output power of each charging device in the next time period. That is, the charging parameter configuration file updated at the last moment of the current time period is sent to the charging device, and the charging device uses Pout as the output power limit of the charging device in the next time period.

[0058] If a new charging device enters the charging state in the next time period, the new charging device is controlled to output with the offline default maximum output power Pout' as the limit value; wherein, the offline default maximum output power is calculated based on the rated power of the substation transformer, the average power load of the substation transformer corresponding to the time period, and the total number of charging devices connected to the substation transformer and distribution system, and the calculation formula is:

[0059]

[0060] Among them, P3 is the average power load of the substation transformer corresponding to the time period (i.e., the next time period), and N is the total number of charging devices connected to the substation power distribution system; P3 can be determined based on the historical average power load of the substation power distribution system corresponding to the time period. The corresponding charging parameter configuration file includes the time period t, the maximum output power Pout of each charging device in the next time period, and the offline default maximum output power Pout'. After entering the next time period, the charging device in the charging state outputs power with the obtained Pout as the limit value. If a new charging device is detected to have entered the charging state during the time period, the new charging device outputs power with Pout' as the limit value.

[0061] Method Embodiment

[0062] The charging control method of the substation transformer distribution network of the present invention first obtains the real-time power load and average power load of the substation transformer in the current time period, and determines the load state level of the substation transformer based on the real-time power load, average power load and rated power of the substation transformer in the current time period; then calculates the available power allocated to the charging equipment under the corresponding load state level, and calculates the maximum output power of each charging equipment in the next time period according to the available power allocated to the charging equipment and the number of charging equipment in the charging state in the substation in the current time period; finally, in the next time period, control each charging equipment in the charging state to output power with the maximum output power of the charging equipment as the limit. The specific implementation process of this method has been described in detail in the system embodiment, and will not be repeated here.

Claims

1. A charging control method for a transformer substation, characterized in that: Including: Obtain the real-time power consumption load and average power consumption load of the substation area transformer within the current time period, and determine the load status level of the substation area transformer based on the real-time power consumption load, average power consumption load of the substation area transformer within the current time period, and the rated power of the substation area transformer; wherein, the real-time power consumption load of the substation area transformer refers to the real-time power consumption load of non-charging equipment within the scope of the substation area. Calculate the available power allocated to the charging equipment corresponding to the load status level, and calculate the maximum output power of each charging equipment in the next time period according to the available power allocated to the charging equipment and the number of charging equipment in the charging state within the current time period. In the next time period, control each charging equipment in the charging state to output power with the maximum output power of the charging equipment as the limit.

2. The charging control method of the transformer substation according to claim 1, characterized in that: The load status levels include Load Status Level One, Load Status Level Two, Load Status Level Three, and Load Status Level Four; the method for determining the load status level of the substation area transformer is: if P1 < P and P1' < P, then the substation area transformer is in Load Status Level One; if P1 > P and P1' < P, then the substation area transformer is in Load Status Level Two; if P1 < P and P1' > P, then the substation area transformer is in Load Status Level Three; if P1 > P and P1' > P, then the substation area transformer is in Load Status Level Four; where, P1 is the real-time power consumption load of the substation area transformer within the current time period, P1' is the average power consumption load of the substation area transformer within the current time period, and P is the rated power of the substation area transformer.

3. The charging control method for the transformer substation network according to claim 2, characterized in that: When the substation area transformer is in Load Status Level One, the available power allocated to the charging equipment is calculated based on the rated power of the substation area transformer and the average power consumption load of the substation area transformer within the current time period, and the calculation formula is: in, To allocate available power to charging equipment.

4. The charging control method for the transformer substation distribution network according to claim 3 is characterized in that: When the substation area transformer is in Load Status Level Two, the available power allocated to the charging equipment is calculated based on the rated power of the substation area transformer, the reserved safety margin, and the average power consumption load of the substation area transformer within the current time period, and the calculation formula is: Where, ΔP is the reserved safety margin of the substation area transformer.

5. The charging control method for the transformer substation network according to claim 4 is characterized in that: When the substation area transformer is in Load Status Level Three, the available power allocated to the charging equipment is calculated based on the rated power of the substation area transformer, the average power consumption load of the substation area transformer within the current time period, and the average output power of all charging equipment connected to the substation area power distribution system within the current time period, and the calculation formula is: Where, P2' is the average output power of all charging equipment connected to the substation area power distribution system within the current time period.

6. The charging control method for the transformer substation network according to claim 4 or 5, characterized in that: When the substation area transformer is in Load Status Level Four, the available power allocated to the charging equipment is calculated based on the rated power of the substation area transformer, the reserved safety margin, the average power consumption load of the substation area transformer within the current time period, and the average output power of all charging equipment connected to the substation area power distribution system within the current time period, and the calculation formula is: Where, P2' is the average output power of all charging equipment connected to the substation area power distribution system within the current time period.

7. The charging control method of the transformer substation network according to claim 1, characterized in that: Use the average distribution method to calculate the distribution of the available power allocated to the charging equipment, and obtain the maximum output power of each charging equipment in the next time period.

8. The charging control method for the transformer substation distribution network according to claim 1, characterized in that: If a new charging device enters the charging state within the next time period, the new charging device will be controlled to output with the offline default maximum output power as the limit; wherein, the offline default maximum output power is calculated based on the rated power of the substation transformer, the average power load of the substation transformer corresponding to the time period, and the total number of charging devices connected to the substation substation distribution system.

9. A charging control system for a transformer substation, characterized in that: It includes an area energy control unit, which is arranged in the area power transformation and distribution system and is used to execute computer program instructions to implement the steps in the area power transformation and distribution network charging control method as described in any one of claims 1-8.

10. The charging control system for the transformer substation distribution network according to claim 9, characterized in that: The energy control unit of the substation communicates with the charging equipment connected to the substation through power carrier communication, RS485 communication or CAN bus communication.

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