A voltage control method for active distribution network with source-grid-load-storage coordination

Abstract

The present invention discloses a source-grid-load-storage coordinated active distribution network voltage control method, comprising: selecting a target area in the active distribution network, wherein the target area includes a plurality of feeders; periodically selecting two feeders i and j that can be operated in a closed loop, and monitoring the terminal voltages of the two feeders in real time to obtain real-time monitoring data; calculating the real-time monitoring data to obtain a voltage difference ΔV between the two feeders. i,j ; respectively, the voltage difference ΔV i,j Compare with different voltage difference setting values, and select to control the voltage on a single feeder according to the comparison result, specifically take the voltage difference at the end of the distribution network feeder as the judgment basis, and maintain the voltage at the end of the distribution network within the standard range through means such as energy storage charging and discharging, load / distributed power supply transfer, and cutting off distributed power supply. The present invention solves the problem of voltage increase at the end of the distribution network caused by the reverse transmission of distributed renewable energy power generation, and at the same time keeps the global voltage of the distribution network within a reasonable range.

Description

Technical Field

[0001] The present invention belongs to the field of distribution network voltage control, and in particular relates to a source-grid-load-storage coordinated active distribution network voltage control method. Background Art

[0002] The distribution network is gradually developing from a single power consumption network to a source-load coexistence direction. More and more distributed renewable energy power generation systems have appeared in the distribution network, which has brought many problems to the operation and control of the distribution network. Among them, the problem of distributed renewable energy power generation backflow leading to increased voltage at the end of the distribution network is particularly prominent.

[0003] At present, some regions are trying to solve this problem by transforming lines, increasing energy storage, and combining voltage control technology. However, traditional voltage control technology mainly adopts on-site decentralized reactive power regulation control method, which not only consumes a lot of investment costs, but also lacks coordination and globality. It is difficult to achieve the expected results, and often makes the control objectives contradictory, which ultimately leads to losing sight of one thing while focusing on another. Therefore, it is urgent to explore voltage control methods that coordinate sources, grids, loads and storage. Summary of the invention

[0004] Purpose of the invention: In order to overcome the deficiencies in the prior art, the present invention provides a source-grid-load-storage coordinated active distribution network voltage control method, which takes the voltage difference at the end of the distribution network feeder as the judgment basis, and maintains the voltage at the end of the distribution network within the standard range through means such as energy storage charging and discharging, load / distributed power supply transfer, and cutting off distributed power supplies.

[0005] Technical solution: In the first aspect, the present invention provides a source-grid-load-storage coordinated active distribution network voltage control method, comprising:

[0006] Selecting a target area in the active distribution network, wherein the target area includes a plurality of feeders;

[0007] Two feeders i and j that can operate in a closed loop are selected periodically, and the terminal voltages of the two feeders are monitored in real time to obtain real-time monitoring data;

[0008] Calculate the real-time monitoring data to obtain the voltage difference ΔV between the two feeders i,j ;

[0009] The voltage difference ΔV i,j The voltage on a single feeder is controlled based on the comparison result to maintain the voltage in the power grid within the range of different voltage difference setting values.

[0010] In a further embodiment, the different pressure difference setting values ​​include: the pressure difference upper limit setting value ΔV lim , Pressure difference upper limit setting value ΔV uplim .

[0011] In a further embodiment, the voltage difference ΔV i,j The method of comparing with different voltage difference setting values ​​and selecting to control the voltage on a single feeder according to the comparison result to maintain the voltage in the power grid within the range of different voltage difference setting values ​​includes:

[0012] When the voltage difference ΔV i,j Less than or equal to the upper limit setting value of the pressure difference ΔV lim When , it means that the voltage difference between the two feeders is normal, and the voltage of a single feeder is controlled separately;

[0013] When the voltage difference ΔV i,j Greater than the upper limit setting value of the pressure difference ΔV lim And less than the upper limit setting value of the pressure difference ΔV uplim When the voltage difference is , the charge and discharge of the energy storage system on the feeder is controlled to reduce the voltage difference.

[0014] When the voltage difference ΔV i,j Greater than or equal to the upper limit setting value of the pressure difference ΔV uplim At this time, the voltage difference is so large that the two feeders cannot be closed synchronously, so the corresponding load branch or distributed power supply branch cannot be adjusted without power outage; on the feeder with a voltage higher than the other feeders, the real-time power and ΔV i,j The distributed power supply branch closest to K is used to reduce the voltage of the feeder with a voltage higher than other feeders, and finally control the voltage difference to the upper limit setting value ΔV uplim the following.

[0015] In a further embodiment, the voltage difference between the two feeders is normal, and the method of controlling the voltage of a single feeder separately includes:

[0016] Determine the voltage V of feeder i respectively i and the voltage V of feeder j j ;

[0017] By switching on and off distributed power sources and controlling the charging and discharging of energy storage, the voltage V i and the voltage V of feeder j j Respectively control the voltage within the set upper and lower limits [V min ,V max ]Inside.

[0018] In a further embodiment, the voltage V of the feeder i is i and the voltage V of feeder j j Respectively control the voltage within the set upper and lower limits [V min ,V max ] also includes:

[0019] If any feeder voltage Vi Greater than the upper limit V max , the corresponding energy storage system is given priority to charge, and the expression of energy storage charging power is:

[0020] P bat =min(P bmax , P0+(V i -V max )K)

[0021] Where P bat Charging power for energy storage system, P bmax is the maximum charging power of energy storage, P0 is the current power of energy storage system, K is the active voltage proportional coefficient;

[0022] If any feeder voltage V i Still greater than the upper limit V max , select power and (V i -V max )K The closest distributed power generation branch is cut off;

[0023] If any feeder voltage V i Less than the lower limit V min , put the distributed power generation branches into the feeder line one by one;

[0024] If any feeder voltage V i Still less than the lower limit V min , control the corresponding energy storage system to discharge, and the expression of energy storage discharge power is:

[0025] P bat =max(P bmin , P0-(V min -V i )K)

[0026] Where P bat Charging power for energy storage system, P bmin is the maximum discharge power of the energy storage (the sign is negative), P0 is the current power of the energy storage system, and K is the active voltage proportional coefficient.

[0027] In a further embodiment, the method of reducing the voltage difference by preferentially controlling the charging and discharging of the energy storage system on the feeder includes:

[0028] The high voltage feeder controls the corresponding energy storage system to charge and the low voltage feeder controls the corresponding energy storage system to discharge;

[0029] If the voltage difference between the feeders is still greater than the upper voltage difference setting value ΔV lim , then adjust the load branch or distributed power branch between the two feeders to restore the voltage difference between the two feeders to less than or equal to the upper limit setting value of the voltage difference ΔV limwithin the normal range;

[0030] Among them, the expression of the energy storage system charging power is:

[0031] P bat =min(P bmax , P0+(V i -V max )K)

[0032] The expression of the energy storage system discharge power is:

[0033] P bat =max(P bmin , P0-(V min -V i )K)

[0034] In a further embodiment, if ΔV i,j Still greater than the upper limit setting value of the pressure difference ΔV lim , compare the distributed power supply branch on the high voltage feeder and the load branch on the low voltage feeder, and select the branch that meets the switching conditions and whose real-time power is consistent with ΔV according to the comparison results. i,j K / 2 is the closest distributed power branch or load branch, and the distributed power branch or load branch is switched to another feeder.

[0035] Beneficial effects: Compared with the prior art, the present invention has the following advantages:

[0036] Through the source-grid-load-storage coordinated voltage control method of the present invention, the voltage difference between the feeders is determined, the charging and discharging of the energy storage system, the switching of the distributed power source branches, and the transfer of the distributed power source branches and the load branches are controlled, and a global coordinated and shared method is used to solve the problem of voltage increase at the end of the distribution network caused by the reverse transmission of distributed renewable energy power generation, while keeping the global voltage of the distribution network within a reasonable range. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 A flow chart of the invented control method;

[0038] Figure 2 It is a diagram of an embodiment of the system architecture of the present invention. DETAILED DESCRIPTION

[0039] In order to more fully understand the technical content of the present invention, the technical solution of the present invention is further introduced and illustrated in conjunction with specific embodiments below, but is not limited thereto.

[0040] Combination Figure 1 The voltage control method of the active distribution network with source-grid-load-storage coordination in this embodiment is further described, including:

[0041] A target area is selected in the active power distribution network, wherein the target area includes a plurality of feeders; wherein the feeders of this embodiment include: feeder 1, feeder 2, and feeder 3.

[0042] Two feeders i and j that can operate in a closed loop are selected periodically and the terminal voltages of the two feeders are monitored in real time; the monitoring data obtained is specifically real-time monitoring data for determining the voltage difference between feeder 1 and feeder 2 or feeder 2 and feeder 3.

[0043] Calculate the real-time monitoring data to obtain the voltage difference ΔV between the two feeders i,j ;

[0044] The voltage difference ΔV i,j Compare with different voltage difference setting values, and select to control the voltage on a single feeder according to the comparison result to maintain the voltage in the power grid within the standard range.

[0045] Different pressure difference setting values ​​include: Pressure difference upper limit setting value ΔV lim , Pressure difference upper limit setting value ΔV uplim .

[0046] The voltage difference ΔV i,j Comparing with different voltage difference setting values, and selecting a method for controlling the voltage on a single feeder according to the comparison result includes:

[0047] When the voltage difference ΔV i,j Less than or equal to the upper limit setting value of the pressure difference ΔV lim When , it indicates that the voltage difference between the two feeders is normal, and the voltage of a single feeder is controlled respectively; in this embodiment, Figure 2 As shown, if the voltage difference between feeder 1 and feeder 2 is less than or equal to the voltage difference upper limit setting value, the voltages of feeder 1 and feeder 2 will be determined respectively, and feeder 1 and feeder 2 will be adjusted respectively.

[0048] When the voltage difference ΔV i,j Greater than the upper limit setting value of the pressure difference ΔV lim And less than the upper limit setting value of the pressure difference ΔV uplim When the voltage difference is , the charge and discharge of the energy storage system on the feeder is controlled to reduce the voltage difference.

[0049] exist Figure 2 In the system shown, if the voltage difference between feeder 1 and feeder 2 is greater than the upper limit setting value of the voltage difference and less than the upper limit setting value of the voltage difference, the voltage difference between feeder 1 and feeder 2 will be reduced by controlling the energy storage system 1 associated with feeder 1 and the energy storage system 2 associated with feeder 2 to charge and discharge. If the line voltage difference is still too large, a suitable branch will be selected from the distributed power branch associated with feeder 2, the load branch associated with feeder 3, and the distributed power branch associated with feeder 3 for transfer.

[0050] When the voltage difference ΔV i,j Greater than or equal to the upper limit setting value of the pressure difference ΔV uplim At this time, the voltage difference is so large that the two feeders cannot be closed synchronously, so the corresponding load branch or distributed power supply branch cannot be adjusted without power outage; on the feeder with a voltage higher than the other feeders, the real-time power and ΔV i,j K is the closest distributed power generation branch, reducing the voltage of the higher voltage feeder and controlling the voltage difference to the upper limit setting value ΔV uplim the following.

[0051] exist Figure 2 In the system shown in the figure, if the voltage difference between feeder 1 and feeder 2 is greater than or equal to the upper limit setting value ΔV uplim , and the voltage of feeder 1 is higher than that of feeder 2, then the distributed power branch associated with feeder 1, the distributed power branch associated with feeder 2, and the distributed power branch associated with feeder 3 are selected to cut off the real-time power and ΔV i,j K is the closest distributed generation branch.

[0052] When the voltage difference between the two feeders is normal, the methods for controlling the voltage of a single feeder include:

[0053] Determine the voltage V of feeder i respectively i and the voltage V of feeder j j ;

[0054] By switching on and off distributed power sources and controlling the charging and discharging of energy storage, the voltage V i and the voltage V of feeder j j Respectively control the voltage within the set upper and lower limits [V min ,V max ]Inside.

[0055] The voltage V of feeder i i and the voltage V of feeder j j Respectively control the voltage within the set upper and lower limits [V min ,V max ] also includes:

[0056] If any feeder voltage V i Greater than the upper limit V max , the energy storage system is given priority to charge, and the expression of energy storage charging power is:

[0057] P bat =min(P bmax , P0+(V i -V max )K)

[0058] Where P batCharging power for energy storage system, P bmax is the maximum charging power of energy storage, P0 is the current power of energy storage system, K is the active voltage proportional coefficient;

[0059] If any feeder voltage V i Still greater than the upper limit V max , select power and (V i -V max )K The closest distributed power generation branch is cut off;

[0060] If any feeder voltage V i Less than the lower limit V min , and put the distributed power generation branches one by one into the corresponding feeder lines;

[0061] If any feeder voltage V i Still less than the lower limit V min , control the energy storage system discharge, the expression of energy storage discharge power is:

[0062] P bat =max(P bmin , P0-(V min -V i )K)

[0063] Where P bat Charging power for energy storage system, P bmin is the maximum discharge power of the energy storage (the sign is negative), P0 is the current power of the energy storage system, and K is the active voltage proportional coefficient.

[0064] Prioritizing the reduction of voltage difference by controlling the charging and discharging of the energy storage system on the feeder includes:

[0065] High voltage feeders control energy storage charging and low voltage feeders control energy storage discharging;

[0066] If the voltage difference between the two feeders is still greater than the upper limit setting value of the voltage difference ΔV lim , then adjust the load branch or distributed power branch between the two feeders to restore the voltage difference between the two feeders to less than or equal to the upper limit setting value of the voltage difference ΔV lim within the normal range;

[0067] Among them, the expression of the energy storage system charging power is:

[0068] P bat =min(P bmax , P0+(V i -V max )K)

[0069] The expression of the energy storage system discharge power is:

[0070] Pbat =max(P bmin , P0-(V min -V i )K)

[0071] If ΔV i,j Still greater than the upper limit setting value of the pressure difference ΔV lim , compare the distributed power supply branch on the high voltage feeder and the load branch on the low voltage feeder, and select the branch that meets the switching conditions and whose real-time power is consistent with ΔV according to the comparison results. i,j K / 2 is the closest load branch or distributed power branch and switches it to another feeder.

[0072] Through the source-grid-load-storage coordinated voltage control method of the present invention, the voltage difference between the feeders is determined, the charging and discharging of the energy storage system, the switching of the distributed power source branches, and the transfer of the distributed power source branches and the load branches are controlled, and a global coordinated and shared method is used to solve the problem of voltage increase at the end of the distribution network caused by the reverse transmission of distributed renewable energy power generation, while keeping the global voltage of the distribution network within a reasonable range.

[0073] The embodiments of the present application may be provided as methods, systems, or computer program products. Therefore, the present application may adopt the form of complete hardware embodiments, complete software embodiments, or embodiments in combination with software and hardware. Moreover, the present application may adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) that contain computer-usable program code.

[0074] The embodiments of the present application may be provided as methods, systems, or computer program products. Therefore, the present application may adopt the form of complete hardware embodiments, complete software embodiments, or embodiments in combination with software and hardware. Moreover, the present application may adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) that contain computer-usable program code.

[0075] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1A device that provides the functions specified in a block or multiple blocks.

[0076] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0077] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0078] The above is only a preferred embodiment of the present invention. Without departing from the technical principle of the present invention, several improvements and modifications can be made, and these improvements and modifications should also be regarded as the protection scope of the present invention.

Claims

1. A source-grid-load-storage coordinated active distribution network voltage control method, characterized in that: include: Selecting a target area in the active distribution network, wherein the target area includes a plurality of feeders; Two feeders i and j that can operate in a closed loop are selected periodically, and the terminal voltages of the two feeders are monitored in real time to obtain real-time monitoring data; Calculate the real-time monitoring data to obtain the voltage difference ΔV between the two feeders i,j ; The voltage difference ΔV i,j Compare with different voltage difference setting values, and select to control the voltage on a single feeder according to the comparison result, so as to maintain the voltage in the power grid within the range of different voltage difference setting values; Different pressure difference setting values ​​include: Pressure difference upper limit setting value ΔV lim , Pressure difference upper limit setting value ΔV uplim ; The voltage difference ΔV i,j The method of comparing with different voltage difference setting values ​​and selecting to control the voltage on a single feeder according to the comparison result to maintain the voltage in the power grid within the range of different voltage difference setting values ​​includes: When the voltage difference ΔV i,j Less than or equal to the upper limit setting value of the pressure difference ΔV lim When , it means that the voltage difference between the two feeders is normal, and the voltage of a single feeder is controlled separately; When the voltage difference ΔV i,j Greater than the upper limit setting value of the pressure difference ΔV lim And less than the upper limit setting value of the pressure difference ΔV uplim When the voltage difference is , the charge and discharge of the energy storage system on the feeder is controlled to reduce the voltage difference. When the voltage difference ΔV i,j Greater than or equal to the upper limit setting value of the pressure difference ΔV uplim At this time, the voltage difference is so large that the two feeders cannot be closed synchronously, so the corresponding load branch or distributed power supply branch cannot be adjusted without power outage; on the feeder with a voltage higher than the other feeders, the real-time power and ΔV i,j The distributed power supply branch closest to K is used to reduce the voltage of the feeder with a voltage higher than other feeders, and finally control the voltage difference to the upper limit setting value ΔV uplim the following; Methods for reducing the voltage difference by preferentially controlling the charging and discharging of the energy storage system on the feeder include: The high voltage feeder controls the corresponding energy storage system to charge and the low voltage feeder controls the corresponding energy storage system to discharge; If the voltage difference between the feeders is still greater than the upper voltage difference setting value ΔV lim , then adjust the load branch or distributed power branch between the two feeders to restore the voltage difference between the two feeders to less than or equal to the upper limit setting value of the voltage difference ΔV lim within the normal range; Among them, the expression of the energy storage system charging power is: P bat =min(P bmax ,P0+(V i -V max )K) The expression of the energy storage system discharge power is: P bat =max(P bmin ,P0-(V min -V i )K)。 2. The source-grid-load-storage coordinated active distribution network voltage control method according to claim 1 is characterized in that: The voltage difference between the two feeders is normal. The methods for controlling the voltage of a single feeder include: Determine the voltage V of feeder i respectively i and the voltage V of feeder j j ; By switching on and off distributed power sources and controlling the charging and discharging of energy storage, the voltage V i and the voltage V of feeder j j Respectively control the voltage within the set upper and lower limits [V min ,V max ]Inside.

3. The source-grid-load-storage coordinated active distribution network voltage control method according to claim 2 is characterized in that: The voltage V of feeder i i and the voltage V of feeder j j Respectively control the voltage within the set upper and lower limits [V min ,V max ] also includes: If any feeder voltage V i Greater than the upper limit V max , the corresponding energy storage system is given priority to charge, and the expression of energy storage charging power is: P bat =min(P bmax ,P0+(V i -V max )K) Where P bat Charging power for energy storage system, P bmax is the maximum charging power of energy storage, P0 is the current power of energy storage system, K is the active voltage proportional coefficient; If any feeder voltage V i Still greater than the upper limit V max , select power and (V i -V max )K The closest distributed power generation branch is cut off; If any feeder voltage V i Less than the lower limit V min , put the distributed power generation branches into the feeder line one by one; If any feeder voltage V i Still less than the lower limit V min , control the corresponding energy storage system to discharge, and the expression of energy storage discharge power is: P bat =max(P bmin ,P0-(V min -V i )K) Where P bat Charging power for energy storage system, P bmin is the maximum discharge power of the energy storage (the sign is negative), P0 is the current power of the energy storage system, and K is the active voltage proportional coefficient.

4. The source-grid-load-storage coordinated active distribution network voltage control method according to claim 3 is characterized in that: If ΔV i,j Still greater than the upper limit setting value of the pressure difference ΔV lim , compare the distributed power supply branch on the high voltage feeder and the load branch on the low voltage feeder, and select the branch that meets the switching conditions and whose real-time power is consistent with ΔV according to the comparison results. i,j K / 2 is the closest distributed power branch or load branch, and the distributed power branch or load branch is switched to another feeder.

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