Multi-zone-area flexible direct current interconnection adaptive power mutual aid control method and multi-zone-area flexible direct current interconnection adaptive power mutual aid control system

Abstract

The invention discloses a multi-zone-area flexible direct current interconnection adaptive power mutual aid control method and system. The method comprises the following steps: setting a working mode of a current converter based on the real-time load condition of a zone area; electrical parameters of the flexible DC interconnection system are adjusted based on different working modes of the converter; and presetting an electrical parameter threshold, judging the operation state of the flexible DC interconnection system based on the electrical parameter and the preset electrical parameter threshold, and dynamically adjusting the load state of the transformer area based on the operation state. According to the invention, power mutual aid control among the transformer areas can be realized without depending on communication, the problem of high load rate of the transformer areas is solved, and stable and economical operation of the transformer areas is realized.

Description

Technical Field

[0001] The present invention relates to the technical field of power electronics control, and in particular, to a multi-substation area flexible DC interconnection adaptive power mutual assistance control method and system. Background Art

[0002] Multiple distribution substations are interconnected by DC flexibly through AC / DC converters, breaking through the limitation of the inherent capacity of a single substation area. The master-slave mode coordination control technology relying on communication is used to realize the dynamic capacity increase and power mutual assistance of the substation areas, and ensure the safe and reliable power supply of important loads. In addition to line losses, the distribution network losses also include transformer or converter losses. Compared with the transformer efficiency reaching 98%, the power conversion efficiency of the converter is about 85%-95%, and its losses seriously affect the loss assessment of the distribution network. However, in the application scenarios where the distance between substation areas is far, the on-site environment is complex, etc., it is inconvenient to lay communication lines and considering minimizing the losses of AC / DC converters, how to dynamically realize the power mutual assistance of substation areas has become a current technical problem. Summary of the Invention

[0003] The purpose of this part is to outline some aspects of the embodiments of the present invention and briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this part, as well as in the abstract and title of the present invention, to avoid obscuring the purpose of this part, the abstract, and the title of the invention, and such simplifications or omissions shall not be used to limit the scope of the present invention.

[0004] In view of the above existing problems, the present invention is proposed.

[0005] Therefore, the present invention provides a multi-substation area flexible DC interconnection adaptive power mutual assistance control method and system to solve the problem that the existing method cannot dynamically adjust the power mutual assistance of substation areas, resulting in a high load rate of substation areas.

[0006] To solve the above technical problems, the present invention provides the following technical solutions:

[0007] In a first aspect, an embodiment of the present invention provides a multi-substation area flexible DC interconnection adaptive power mutual assistance control method, including: setting the working mode of the converter based on the real-time load condition of the substation area;

[0008] Adjusting the electrical parameters of the flexible DC interconnection system based on different working modes of the converter;

[0009] Presetting the electrical parameter thresholds, judging the operating state of the flexible DC interconnection system based on the electrical parameters and the preset electrical parameter thresholds, and dynamically adjusting the load state of the substation area based on the operating state.

[0010] As a preferred embodiment of the multi-substation flexible DC interconnected adaptive power mutual assistance control method of the present invention, wherein: the setting of the converter operating mode includes:

[0011] If the substation is a heavily loaded substation, set its converter as a voltage source in droop mode;

[0012] If the substation is a lightly loaded or fully loaded substation, set its converter as a power source in constant power mode.

[0013] As a preferred embodiment of the multi-substation flexible DC interconnected adaptive power mutual assistance control method of the present invention, wherein: the electrical parameters of the flexible DC interconnected system include voltage and power, and adjusting the electrical parameters of the flexible DC interconnected system based on different operating modes of the converter includes:

[0014] The flexible DC interconnected system is established based on the voltage source in droop mode, and the voltage of the flexible DC interconnected system is controlled by dynamically adjusting the droop voltage. For the substation in constant power mode, its output or input power is automatically adjusted according to the DC link voltage.

[0015] As a preferred embodiment of the multi-substation flexible DC interconnected adaptive power mutual assistance control method of the present invention, wherein: the establishment of the flexible DC interconnected system includes:

[0016] When the DC link voltage is not greater than the first threshold, the flexible DC interconnected system is in a closed state;

[0017] When the DC link voltage is greater than the first threshold, the flexible DC interconnected system is in an established state;

[0018] If the converter valve of the substation converter is in an operating state and the DC switch is in a closed position, the substation is in an interconnected state; otherwise, the substation is in an off-grid state.

[0019] As a preferred embodiment of the multi-substation flexible DC interconnected adaptive power mutual assistance control method of the present invention, wherein: preset the electrical parameter thresholds, and based on the electrical parameters and the preset electrical parameter thresholds, judge the operating state of the flexible DC interconnected system, and dynamically adjust the load state of the substation based on the operating state, including:

[0020] When the DC link voltage is less than the preset threshold, the power mutual assistance of the flexible DC interconnected system is insufficient;

[0021] When the DC link voltage is equal to the preset threshold, the power mutual assistance of the flexible DC interconnected system is balanced;

[0022] When the DC link voltage is greater than the preset threshold, the power mutual assistance of the flexible DC interconnected system is excessive;

[0023] When the flexible DC interconnected system is in the establishment state and the power mutual assistance is insufficient, if any substation area is in the light load state and off-grid state, then according to the preset power mutual assistance level, the converter is switched to the constant power source mode, and the light load substation area provides additional power equal to the power surplus of the substation area to the flexible DC interconnected system to balance the system power;

[0024] When the flexible DC interconnected system is in the establishment state and the power mutual assistance is balanced or in surplus, if any substation area is in the heavy load state and off-grid state, then according to the preset power mutual assistance level, the converter is switched to the constant power source mode and added to the flexible DC interconnected system, and the heavy load substation area obtains the required additional power from the flexible DC interconnected system to balance the system power;

[0025] When the flexible DC interconnected system is in the establishment state and this substation area is in the interconnected state and serves as a voltage source in the droop mode, if this substation area is in the heavy load state or light load state, then the droop voltage is dynamically adjusted according to the actual load condition of the current substation area;

[0026] When the flexible DC interconnected system is in the establishment state and this substation area is in the interconnected state, if the voltage source in the droop mode of this substation area is in the light load state and the DC tie line voltage is greater than the preset threshold, then the active power is determined according to the delay, it is determined that there is no power mutual assistance requirement between substation areas, there is no power mutual assistance in the flexible DC interconnected system, the converter of this substation area is switched to the long standby state, and the AC and DC switches are disconnected to turn off the flexible DC interconnected system. As a preferred solution of the multi-substation area flexible DC interconnected adaptive power mutual assistance control method described in the present invention, it further includes:

[0027] When the flexible DC interconnected system is in the establishment state and this substation area serves as a power source in the constant power mode and is in the light load state, the constant power value is dynamically adjusted according to the substation area power mutual assistance level;

[0028] When the flexible DC interconnected system is in the establishment state and this substation area serves as a power source in the constant power mode and is in the heavy load state, the constant power value output by it is dynamically adjusted according to the substation area power mutual assistance level;

[0029] When the flexible DC interconnected system is in the establishment state and this substation area serves as a power source in the constant power mode and is in the full load or light load state, if the DC tie line voltage is not less than the preset threshold, then the active power is determined according to the delay, it is determined that this substation area does not need to participate in power mutual assistance, the converter of this substation area is switched to the long standby state, and the AC and DC switches are disconnected to withdraw from the flexible DC interconnected system.

[0030] In a second aspect, the present invention provides a multi-substation area flexible DC interconnected adaptive power mutual assistance control system, including: an operation module for setting the working mode of the converter based on the real-time load condition of the substation area;

[0031] An adjustment module for adjusting the electrical parameters of the flexible DC interconnected system based on different operating modes of the converter;

[0032] A control module for presetting the threshold of the electrical parameters, judging the operating state of the flexible DC interconnected system based on the electrical parameters and the preset electrical parameter threshold, and dynamically adjusting the load state of the substation area based on the operating state.

[0033] As a preferred solution of the multi-substation area flexible DC interconnected adaptive power mutual assistance control method of the present invention, wherein: the control module is used for:

[0034] When the DC tie line voltage is less than the preset threshold, the power mutual assistance of the flexible DC interconnected system is insufficient;

[0035] When the DC tie line voltage is equal to the preset threshold, the power mutual assistance of the flexible DC interconnected system is balanced;

[0036] When the DC tie line voltage is greater than the preset threshold, the power mutual assistance of the flexible DC interconnected system is excessive;

[0037] When the flexible DC interconnected system is in the established state and the power mutual assistance is insufficient, if any substation area is in the light load state and off-grid state, then according to the preset power mutual assistance level, the converter is switched to the constant power source mode, and the light load substation area provides additional power equal to the power surplus of the substation area to the flexible DC interconnected system to balance the system power;

[0038] When the flexible DC interconnected system is in the established state and the power mutual assistance is balanced or excessive, if any substation area is in the heavy load state and off-grid state, then according to the preset power mutual assistance level, the converter is switched to the constant power source mode and added to the flexible DC interconnected system, and the heavy load substation area obtains the required additional power from the flexible DC interconnected system to balance the system power;

[0039] When the flexible DC interconnected system is in the established state and this substation area is in the interconnected state and is a voltage source in the droop mode, if this substation area is in the heavy load state or the light load state, then the droop voltage is dynamically adjusted according to the actual load condition of the current substation area;

[0040] When the flexible DC interconnected system is in the established state and this substation area is in the interconnected state, if the voltage source in the droop mode of this substation area is in the light load state and the DC tie line voltage is greater than the preset threshold, then the active power is determined according to the delay, it is determined that there is no power mutual assistance requirement between substation areas, there is no power mutual assistance in the flexible DC interconnected system, the converter of this substation area is switched to the long standby state, and the AC and DC switches are disconnected to turn off the flexible DC interconnected system.

[0041] In a third aspect, the present invention provides an electronic device, including:

[0042] A memory and a processor;

[0043] The memory is used to store computer-executable instructions, and the processor is used to execute the computer-executable instructions. When the computer-executable instructions are executed by the processor, the steps of the multi-substation flexible DC interconnected adaptive power mutual assistance control method are implemented.

[0044] In a fourth aspect, the present invention provides a computer-readable storage medium storing computer-executable instructions, and when the computer-executable instructions are executed by a processor, the steps of the multi-substation flexible DC interconnected adaptive power mutual assistance control method are implemented.

[0045] Compared with the prior art, the beneficial effects of the present invention are as follows: The present invention provides a multi-substation flexible DC interconnected adaptive power mutual assistance control method and system. Under the full-load state of the substation transformer, according to the real-time load of the present substation, the droop voltage is calculated by using the droop control formula and sent to the converter valve to output the DC tie line voltage, thereby establishing a flexible DC interconnected system; when the system power is insufficient, the substation in the light-load state accesses the system as a power source in the constant-power mode; when the system power is balanced or excessive, the substation in the heavy-load state accesses the system as a power source in the constant-power mode; the voltage source operates based on the full-load state of the substation transformer under the light or heavy load state of the substation transformer, and adjusts the DC tie line voltage to reflect the under-power state or over-power state of the system; the constant-power value of the converter valve of the present substation is adjusted by the constant-power mode power source in the heavy-load state according to the required compensation power, and the constant-power value of the converter valve of the present substation is adjusted by the constant-power mode power source in the light-load state according to the DC tie line voltage; when there is no active power flowing in or out of the AC / DC converter of the power source substation, the power source substation exits the flexible DC interconnected system; the voltage source substation determines that there is no power mutual assistance in the flexible DC interconnected system and then exits and shuts down the flexible DC interconnected system.

[0046] This system does not require communication between substations and is particularly suitable for application scenarios where it is inconvenient to lay communication lines, such as long distances between substations and complex on-site environments. When there is no power mutual assistance, the substation automatically exits the flexible DC interconnected system, and the AC / DC converter is in a long standby state, saving power and cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts. Among them:

[0048] Figure 1Schematic diagram of the method flow of a multi-substation flexible DC interconnected adaptive power mutual assistance control method and system according to an embodiment of the present invention;

[0049] Figure 2 Power mutual assistance control flow chart of a multi-substation flexible DC interconnected adaptive power mutual assistance control method and system according to an embodiment of the present invention;

[0050] Figure 3 Schematic diagram of the grid structure of a multi-substation flexible DC interconnected adaptive power mutual assistance control method and system according to an embodiment of the present invention;

[0051] FIG. 4 is a schematic diagram of the implementation of a 3-substation flexible DC interconnected adaptive power mutual assistance control system of a multi-substation flexible DC interconnected adaptive power mutual assistance control method and system according to an embodiment of the present invention;

[0052] Among them, (a) in FIG. 4 is a schematic diagram of the grid structure in the initial state of the 3 substations, (b) in FIG. 4 is a schematic diagram of the grid structure when the first substation initiates the system establishment, (c) in FIG. 4 is a schematic diagram of the grid structure when the third lightly loaded substation joins the system, (d) in FIG. 4 is a schematic diagram of the grid structure when the second substation changes from a lightly loaded state to a heavily loaded state, (e) in FIG. 4 is a schematic diagram of the grid structure when the second substation adjusts its power, (f) in FIG. 4 is a schematic diagram of the grid structure when the third lightly loaded substation increases its power output, (g) in FIG. 4 is a schematic diagram of the grid structure when the second substation exits the system, (h) in FIG. 4 is a schematic diagram of the grid structure when the third lightly loaded substation reduces its power output, (i) in FIG. 4 is a schematic diagram of the grid structure when the first substation becomes lightly loaded, (j) in FIG. 4 is a schematic diagram of the grid structure when the third lightly loaded substation completely exits the system, and (k) in FIG. 4 is a schematic diagram of the grid structure when the first substation exits the system. Detailed implementation manners

[0053] In order to make the above objects, features, and advantages of the present invention more obvious and understandable, the following will describe the detailed implementation manners of the present invention in conjunction with the drawings of the specification. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative work shall fall within the protection scope of the present invention.

[0054] In the following description, many specific details are set forth in order to fully understand the present invention. However, the present invention can also be implemented in other ways different from those described herein. Those skilled in the art can make similar extensions without departing from the connotation of the present invention. Therefore, the present invention is not limited by the specific embodiments disclosed below.

[0055] Secondly, the so-called "one embodiment" or "embodiment" herein refers to specific features, structures or characteristics that may be included in at least one implementation manner of the present invention. The appearances of "in one embodiment" in different places in this specification do not all refer to the same embodiment, nor are they separate or alternative embodiments that exclude each other with other embodiments.

[0056] The present invention will be described in detail in conjunction with schematic diagrams. When describing the embodiments of the present invention in detail, for the convenience of explanation, the cross-sectional views showing the device structure will be enlarged locally in a non-general proportion, and the schematic diagrams are only examples, which should not limit the protection scope of the present invention here. In addition, in actual production, three-dimensional spatial dimensions including length, width and depth should be included.

[0057] At the same time, in the description of the present invention, it should be noted that the orientation or positional relationship indicated by terms such as "upper, lower, inner and outer" is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation to the present invention. In addition, the terms "first, second or third" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0058] Unless otherwise clearly defined and limited in the present invention, the terms "installed, connected, connected" should be understood in a broad sense. For example: it can be a fixed connection, a detachable connection or an integral connection; it can also be a mechanical connection, an electrical connection or a direct connection, and can also be indirectly connected through an intermediate medium, or can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0059] Embodiment 1

[0060] Referring to Figures 1 to 3 , which is an embodiment of the present invention, this embodiment provides a multi-region flexible DC interconnection adaptive power mutual assistance control method, including:

[0061] S100: Set the working mode of the converter based on the real-time load situation of the region;

[0062] S200: Adjust the electrical parameters of the flexible DC interconnection system based on different working modes of the converter;

[0063] S300: Preset electrical parameter thresholds, and based on the electrical parameters and the preset electrical parameter thresholds, judge the operating state of the flexible DC interconnection system, and dynamically adjust the load state of the region based on the operating state.

[0064] It should be noted that in the embodiments of the present invention, an adaptive power mutual assistance control device is configured for each substation area. The substation areas are interconnected through a flexible AC / DC converter and a DC 750V DC tie line to form a flexible DC interconnected system, which can flexibly adjust the voltage and power direction of the DC tie line to achieve power mutual assistance between substation areas. When each substation area is not overloaded, the AC / DC converter of the substation area is in a long standby state and the DC tie switch is disconnected, and each substation area operates independently.

[0065] In the embodiments of the present invention, the set working modes of the converter include:

[0066] If the substation area is an overloaded substation area, its converter is set as a voltage source in the droop mode;

[0067] If the substation area is a lightly loaded or fully loaded substation area, its converter is set as a power source in the constant power mode.

[0068] In the embodiments of the present invention, the electrical parameters of the flexible DC interconnected system include voltage and power. Adjusting the electrical parameters of the flexible DC interconnected system based on different working modes of the converter includes:

[0069] The flexible DC interconnected system is established based on a voltage source in the droop mode. By dynamically adjusting the droop voltage, the voltage of the flexible DC interconnected system is controlled. The substation areas in the constant power mode automatically adjust their output or input power according to the DC tie line voltage.

[0070] It should be noted that for the substation area with a voltage source operating in the droop mode: the first overloaded substation area in the system serves as the voltage source, which is responsible for the establishment, shutdown of the flexible DC interconnected system and the stable operation of the DC tie line voltage, and adjusts the droop voltage in real time according to the load of the substation area, reflecting the unbalanced state of the system power.

[0071] For the substation area with a power source operating in the constant power mode: the lightly loaded substation areas in the system adjust the constant power value in real time according to the system power shortage and system power surplus conditions to maintain the balanced state of the system power.

[0072] In the embodiments of the present invention, setting the working mode of the converter based on the real-time load condition of the substation area can, according to the load change of the substation area, compare the variable load rate of the substation area with the set load rate limit value of the substation area to determine the working state of this substation area, which is expressed as:

[0073] β = P tl / S e

[0074] Among them, β is the variable load rate of the substation area, P tl is the variable real-time power of the substation area, and S e is the rated apparent power of the substation area.

[0075] When β > β set, the substation in the area is overloaded, and the power deficit of the substation in the area is ΔP qe-t = P e - P load ;

[0076] When β = β set , the substation in the area is fully loaded;

[0077] When β < β set , the substation in the area is lightly loaded, and the power surplus of the substation in the area is ΔP gs-t = P e - P load .

[0078] Among them, β set is the load rate limit of the substation in the area, P e is the full-load power of the substation in the area, P load is the load power of the area, P pcs is the active power of the PCS;

[0079] Specifically, the full-load power of the substation in the area is expressed as:

[0080] P e = S e × β set

[0081] Specifically, the load power of the area is expressed as:

[0082] P load = P tl - P pcs

[0083] It should be noted that the active power of the PCS is a real-time monitored value. When P pcs < 0, the power flows into the area; when P pcs > 0, the power flows out of the area.

[0084] In the embodiment of the present invention, the establishment of the flexible DC interconnected system includes:

[0085] When the voltage of the DC connection line is not greater than the first threshold, the flexible DC interconnected system is in the off state;

[0086] When the voltage of the DC connection line is greater than the first threshold, the flexible DC interconnected system is in the established state;

[0087] If the converter valve of the area converter is in the operating state and the DC switch is in the closed position, the area is in the interconnected state; otherwise, the area is in the off-grid state.

[0088] In an optional embodiment, the area measures the voltage V of the DC connection line in real time dc and the no-voltage setting value V of the DC connection line nullCompare with the operation status of the AC / DC converter valve and the DC switch position signal to determine whether the flexible DC interconnected system is established and the interconnection status of the power distribution area.

[0089] When V dc ≤V null , the flexible DC interconnected system is in the closed state;

[0090] When V dc >V null , the flexible DC interconnected system is in the established state;

[0091] If the operation status of the AC / DC converter valve in the power distribution area and the DC switch is in the closed position, then the interconnection status of the power distribution area; otherwise, the power distribution area is in the off-grid state.

[0092] In the embodiment of the present invention, a preset electrical parameter threshold is set. Based on the electrical parameters and the preset electrical parameter threshold, the operation status of the flexible DC interconnected system is judged, and the load status of the power distribution area is dynamically adjusted based on the operation status, including:

[0093] When the voltage of the DC tie line is less than the preset threshold, the power mutual assistance of the flexible DC interconnected system is insufficient;

[0094] When the voltage of the DC tie line is equal to the preset threshold, the power mutual assistance of the flexible DC interconnected system is balanced;

[0095] When the voltage of the DC tie line is greater than the preset threshold, the power mutual assistance of the flexible DC interconnected system is excessive.

[0096] In an alternative embodiment, the power distribution area compares the voltage V dc of the DC tie line measured in real time with the preset stable operating voltage V dcs of the DC tie line to determine the power mutual assistance status of the flexible DC interconnected system.

[0097] When V dc <V dcs , the power mutual assistance of the system is insufficient, and the power deficit ΔP qe-f =(V dc -V dcs ) / K dp >0;

[0098] When V dc =V dcs , the power mutual assistance of the system is balanced;

[0099] When V dc >V dcs , the power mutual assistance of the system is excessive, and the power surplus ΔP gs-f =(V dc -V dcs ) / K dp <0.

[0100] In an optional embodiment, in the flexible DC interconnected system in the off state (the area AC / DC converter operates in a long standby state, the AC switches and DC switches on the upper and lower sides of the AC / DC converter are disconnected, and the DC tie line voltage V dc equals 0) and in the case of heavy overload of the area transformer in the islanded state, the AC / DC converter switches to a voltage source in the working droop mode, and issues the droop voltage V dp which is expressed as:

[0101] V dp = V dcs - K dp ×ΔP qe-t

[0102] where V dp is the DC droop no-load voltage, V dcs is the stable operating voltage of the DC tie line, and K dp is the voltage source droop coefficient.

[0103] When the flexible DC interconnected system is in the established state (the establishment of the DC tie line voltage represents the establishment of the flexible DC interconnected system), since there is no power transfer between the areas at this time, the DC tie line voltage V dc equals the converter droop voltage and is expressed as:

[0104] V dc = V dp <V dcs

[0105] The flexible DC interconnected system is in a state of insufficient power mutual assistance.

[0106] It should be noted that for the power mutual assistance level setting between different areas, a delay mechanism is adopted to divide the priorities to ensure that when there is a power imbalance in the system, the corresponding areas can be connected orderly for regulation.

[0107] In the embodiment of the present invention, it further includes: when the flexible DC interconnected system is in the established state and there is insufficient power mutual assistance, if any area is in the light load state and in the islanded state, then according to the preset power mutual assistance level, the converter is switched to the constant power source mode, and the light load area provides additional power equal to the power surplus of the area to the flexible DC interconnected system to balance the system power;

[0108] Specifically, the AC / DC converter is switched to a power source in the constant power source mode and added to the flexible DC interconnected system, and the constant power value P adj for power transfer is issued, which is expressed as:

[0109] P adj = ΔP qe-f

[0110] When the flexible DC interconnection system is in the establishment state and the power mutual assistance is balanced or in excess, if any substation is in a heavy-load state and is off-grid, the converter will be switched to the constant power source mode according to the preset power mutual assistance level and added to the flexible DC interconnection system. The heavy-load substation will obtain the required additional power from the flexible DC interconnection system to balance the system power.

[0111] Specifically, the AC / DC converter switches to a power source in a constant power source mode, joins the flexible DC interconnection system, and issues a constant power value P for transfer. adj It is expressed as:

[0112] P adj =ΔP qe-t

[0113] In an embodiment of the present invention, it also includes:

[0114] When the flexible DC interconnection system is in the establishment state and the current substation is in the interconnection state, as a voltage source in the droop mode, if the current substation is in the heavy load state or light load state, the droop voltage is dynamically adjusted according to the actual load condition of the current substation;

[0115] Specifically, the droop voltage is dynamically adjusted according to the actual load condition of the current substation as follows:

[0116] V dp =V dcs -K dp ×ΔP t

[0117] Where ΔP t =P e -P load .

[0118] When the flexible DC interconnection system is in the establishment state and the current substation is in the interconnection state, if the voltage source in the droop mode of the substation is in a light load state and the DC interconnection line voltage is greater than the preset threshold, the active power is determined based on the delay, and it is determined that there is no power mutual assistance demand between the substations, and the flexible DC interconnection system has no power mutual assistance. The converter of this substation is switched to the long standby state, and the AC and DC switches are disconnected to shut down the flexible DC interconnection system.

[0119] Specifically, when the flexible DC interconnection system is in the established state, the interconnection state of the local area and the voltage source in the working droop mode is lightly loaded, the DC interconnection line voltage V dc =V dp >V dcs , after a delay of P pcs= 0, it can be determined that there is no need for power mutual assistance between substations, and there is no power mutual assistance in the flexible DC interconnected system. The AC / DC converter in this substation switches to the long standby state, and the AC and DC switches are disconnected, and the flexible DC interconnected system is shut down.

[0120] In the embodiment of the present invention, it further includes:

[0121] When the flexible DC interconnected system is in the established state, and this substation is in a light load state as a power source in the constant power mode, dynamically adjust the constant power value according to the power mutual assistance level of the substation area;

[0122] Specifically, dynamically adjusting the constant power value according to the power mutual assistance level of the substation area is expressed as:

[0123] P adj = ΔP t

[0124] Wherein, ΔP t = P e -P load .

[0125] When the flexible DC interconnected system is in the established state, and this substation is in a heavy load state as a power source in the constant power mode, dynamically adjust the constant power value output according to the power mutual assistance level of the substation area;

[0126] When the flexible DC interconnected system is in the established state, and this substation is in a full load or light load state as a power source in the constant power mode, if the DC tie line voltage is not less than the preset threshold, determine the active power according to the delay, determine that this substation does not need to participate in power mutual assistance, switch the converter of this substation to the long standby state, and disconnect the AC and DC switches, and exit the flexible DC interconnected system.

[0127] Specifically, in the flexible DC interconnected system in the established state, when this substation's interconnection state and the power source in the working constant power mode are in full load or light load, the DC tie line voltage V dc ≥ V dcs , after the delay P pcs = 0, it can be determined that the system power mutual assistance is balanced or excessive, and this substation does not need power mutual assistance. The AC / DC converter of this substation switches to the long standby state, and the AC and DC switches are disconnected, and exits the flexible DC interconnected power mutual assistance system.

[0128] It should be noted that the present invention divides the transformer substation areas into light load, full load, and heavy load states according to the load rate. One heavy load transformer substation area sets the converter as a voltage source in the droop mode to initiate the establishment of a flexible DC interconnected system, and the other light load transformer substation areas and heavy load transformer substation areas set the converters as power sources in the constant power mode and automatically connect to the flexible DC interconnected system. In the flexible DC interconnected system, the stable transmission of power depends on the stability of the DC tie line voltage. The voltage source in the droop mode adjusts the droop voltage according to the load power of the transformer substation area to achieve system voltage stability. The light load power source in the constant power mode automatically adjusts the constant power setting value according to the DC tie line voltage to achieve constant power supply, and the heavy load power source in the constant power mode automatically adjusts the constant power setting value according to the load rate to achieve constant power power taking. In the flexible DC interconnected system, the power source transformer substation areas in the constant power mode automatically withdraw from the flexible DC interconnected system according to the reactive power mutual assistance in their own areas, and the voltage source transformer substation areas in the droop mode automatically shut down the flexible DC interconnected system according to the reactive power mutual assistance in the system. The present invention can realize the reactive power mutual assistance control between transformer substation areas without relying on communication, solve the problem of high load rate in transformer substation areas, and realize the stable and economic operation of transformer substation areas.

[0129] Embodiment 2

[0130] The above embodiment is a schematic solution of a multi-transformer substation area flexible DC interconnected adaptive reactive power mutual assistance control method. It should be noted that the technical solution of this multi-transformer substation area flexible DC interconnected adaptive reactive power mutual assistance control system belongs to the same concept as the technical solution of the above multi-transformer substation area flexible DC interconnected adaptive reactive power mutual assistance control method. For the details not described in detail in the technical solution of the multi-transformer substation area flexible DC interconnected adaptive reactive power mutual assistance control system in this embodiment, reference can be made to the description of the technical solution of the above multi-transformer substation area flexible DC interconnected adaptive reactive power mutual assistance control method.

[0131] A multi-transformer substation area flexible DC interconnected adaptive reactive power mutual assistance control system in this embodiment includes:

[0132] An operation module, configured to set the working mode of the converter based on the real-time load condition of the transformer substation area;

[0133] An adjustment module, configured to adjust the electrical parameters of the flexible DC interconnected system based on different working modes of the converter;

[0134] A control module, configured to preset electrical parameter thresholds, judge the operating state of the flexible DC interconnected system based on the electrical parameters and the preset electrical parameter thresholds, and dynamically adjust the load state of the transformer substation area based on the operating state.

[0135] In the embodiment of the present invention, the operation module is used for:

[0136] If the transformer substation area is a heavy load transformer substation area, set its converter as a voltage source in the droop mode;

[0137] If the substation area is a lightly loaded or fully loaded substation area, set its converter to a power source in constant power mode.

[0138] In the embodiments of the present invention, the electrical parameters of the flexible DC interconnected system include voltage and power. The adjustment module is specifically used for:

[0139] The flexible DC interconnected system is established based on a droop-mode voltage source. By dynamically adjusting the droop voltage, the voltage of the flexible DC interconnected system is controlled. The substation area in constant power mode automatically adjusts its output or input power according to the DC tie line voltage.

[0140] In the embodiments of the present invention, the adjustment module is further used for:

[0141] When the DC tie line voltage is not greater than the first threshold, the flexible DC interconnected system is in a closed state;

[0142] When the DC tie line voltage is greater than the first threshold, the flexible DC interconnected system is in an established state;

[0143] If the converter valve of the substation area converter is in an operating state and the DC switch is in the closed position, the substation area is in an interconnected state; otherwise, the substation area is in an off-grid state.

[0144] In the embodiments of the present invention, the control module is used for:

[0145] When the DC tie line voltage is less than the preset threshold, the power mutual assistance of the flexible DC interconnected system is insufficient;

[0146] When the DC tie line voltage is equal to the preset threshold, the power mutual assistance of the flexible DC interconnected system is balanced;

[0147] When the DC tie line voltage is greater than the preset threshold, the power mutual assistance of the flexible DC interconnected system is excessive;

[0148] When the flexible DC interconnected system is in an established state and the power mutual assistance is insufficient, if any substation area is in a lightly loaded state and in an off-grid state, according to the preset power mutual assistance level, switch the converter to the constant power source mode. This lightly loaded substation area provides additional power equal to the power surplus of the substation area to the flexible DC interconnected system to balance the system power;

[0149] When the flexible DC interconnected system is in an established state and the power mutual assistance is balanced or excessive, if any substation area is in a heavily loaded state and in an off-grid state, according to the preset power mutual assistance level, switch the converter to the constant power source mode and add it to the flexible DC interconnected system. This heavily loaded substation area obtains the required additional power from the flexible DC interconnected system to balance the system power;

[0150] When the flexible DC interconnected system is in the establishment state and this station area is in the interconnected state, and it serves as a voltage source in the droop mode, if this station area is in a heavy load state or a light load state, the droop voltage is dynamically adjusted according to the actual load condition of the current station area.

[0151] When the flexible DC interconnected system is in the establishment state and this station area is in the interconnected state, if the voltage source in the droop mode of this station area is in a light load state and the DC tie line voltage is greater than the preset threshold, the active power is determined according to the delay, it is determined that there is no power mutual assistance requirement between the station areas, there is no power mutual assistance in the flexible DC interconnected system, the converter of this station area is switched to the long standby state, and the AC and DC switches are disconnected to turn off the flexible DC interconnected system.

[0152] In the embodiment of the present invention, the control module is further used for:

[0153] When the flexible DC interconnected system is in the establishment state, and this station area serves as a power source in the constant power mode and is in a light load state, the constant power value is dynamically adjusted according to the power mutual assistance level setting of the station area.

[0154] When the flexible DC interconnected system is in the establishment state, and this station area serves as a power source in the constant power mode and is in a heavy load state, the constant power value output by it is dynamically adjusted according to the power mutual assistance level setting of the station area.

[0155] When the flexible DC interconnected system is in the establishment state, and this station area serves as a power source in the constant power mode and is in a full load or light load state, if the DC tie line voltage is not less than the preset threshold, the active power is determined according to the delay, it is determined that this station area does not need to participate in power mutual assistance, the converter of this station area is switched to the long standby state, and the AC and DC switches are disconnected to exit the flexible DC interconnected system.

[0156] In an optional embodiment, the operation module is further used for: the droop mode voltage source unit and the flexible DC interconnected system establishment unit;

[0157] The droop mode voltage source unit is used to establish the first heavy-load station area as the voltage source before the flexible DC interconnected system is established, and the converter valve of its station area operates in the droop mode and establishes the DC tie line voltage.

[0158] The flexible DC interconnected system establishment unit is used for the voltage source to calculate the droop voltage according to the real-time load when the station area becomes full load, and issue it to the AC / DC converter to output the DC tie line voltage to establish the flexible DC interconnected system.

[0159] In an optional embodiment, the adjustment module is further used for: the constant power mode power source unit, the system DC voltage adjustment unit and the system mutual assistance power adjustment unit;

[0160] A constant power mode power source unit is used to be connected to the system as a power source of the substation area in the light load state when the flexible DC interconnected system is established and the system power is insufficient; and to be connected to the system as a power source of the substation area in the heavy load state when the system power is balanced or excessive.

[0161] A system DC voltage regulation unit is used to work based on the full load state of the substation area when the voltage source is in the light or heavy load state of the substation area. According to the real-time load of this substation area, the droop voltage is calculated by using the droop control formula and sent to the AC / DC converter to regulate the DC tie line voltage to reflect the under-power state or over-power state of the system.

[0162] A system mutual power regulation unit is used to regulate the constant power value of the AC / DC converter of this substation area by the constant power mode power source in the heavy load state according to the required compensation power, and to regulate the constant power value of the AC / DC converter of this substation area by the constant power mode power source in the light load state according to the DC tie line voltage.

[0163] In an optional embodiment, the control module is further used for: a power source withdrawal unit and a voltage source withdrawal and system shutdown unit.

[0164] The power source withdrawal unit is used to withdraw from the flexible DC interconnected system as a power source substation area when there is no active power flowing in or out of the AC / DC converter of this substation area.

[0165] The voltage source withdrawal and system shutdown unit is used for when V dc = V dp There is no power mutual aid between substations in the system. It is judged that there is no power source in the system. At this time, the AC / DC converter switches to the long standby state, and the AC and DC switches are disconnected, and the flexible DC interconnected system is shut down, and each substation area is independent.

[0166] Embodiment 3

[0167] This embodiment provides an electronic device, which is applicable to the case of the multi-substation area flexible DC interconnected adaptive power mutual aid control method, including:

[0168] A memory and a processor; the memory is used to store computer-executable instructions, and the processor is used to execute the computer-executable instructions to implement the multi-substation area flexible DC interconnected adaptive power mutual aid control method as proposed in the above embodiment.

[0169] Embodiment 4

[0170] This embodiment provides a storage medium, on which a computer program is stored, and when the program is executed by a processor, it implements the multi-substation area flexible DC interconnected adaptive power mutual aid control method as proposed in the above embodiment.

[0171] The storage medium proposed in this embodiment belongs to the same inventive concept as the method for realizing adaptive power mutual assistance control for flexible DC interconnection among multiple substations. Technical details not described in detail in this embodiment can be referred to the above embodiments, and this embodiment has the same beneficial effects as the above embodiments.

[0172] Those skilled in the art should understand that the embodiments of the present invention can be provided as a method, a system, or a computer program product. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present invention can take 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.) containing computer-usable program code.

[0173] The present invention is described with reference to the flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to the embodiments of the present invention. It should be understood that each process and / or block in the flowchart and / or block diagram can be implemented by computer program instructions, and the combination of the processes and / or blocks in the flowchart and / or block diagram can also be implemented by computer program instructions. These computer program instructions can be provided to the processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing devices to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing devices generate a device for realizing the functions specified in Figure 1 one process or multiple processes and / or blocks Figure 1 one block or multiple blocks.

[0174] These computer program instructions can also be stored in a computer-readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer-readable memory generate a manufactured article including an instruction device, and the instruction device realizes the functions specified in Figure 1 one process or multiple processes and / or blocks Figure 1 one block or multiple blocks.

[0175] These computer program instructions can also be loaded onto a computer or other programmable data processing device, so that a series of operation steps are executed on the computer or other programmable device to generate a computer-implemented process, and thus the instructions executed on the computer or other programmable device provide steps for realizing the functions specified in Figure 1 one process or multiple processes and / or blocks Figure 1 one block or multiple blocks.

[0176] The above is only the preferred embodiment of the present invention. It should be noted that for those of ordinary skill in the art in the technical field, without departing from the technical principle of the present invention, several improvements and deformations can be made, and these improvements and deformations should also be regarded as the protection scope of the present invention.

[0177] Embodiment 5

[0178] Referring to FIG. 4, which is an embodiment of the present invention. In this embodiment of the present invention, taking 3 power distribution areas as an example, flexible DC interconnection adaptive power mutual assistance control is carried out to verify the feasibility and beneficial effects of the present invention.

[0179] In the embodiment of the present invention, the power mutual assistance level of the power distribution areas is set as: Substation #3 > Substation #2 > Substation #1.

[0180] As shown in FIG. 4(a), in the case of no overload in the power distribution areas, the AC / DC converters of each independently operating power distribution area operate in a long standby state, the AC switches and DC switches on the upper and lower sides of the AC / DC converter are disconnected, and each power distribution area is in an off-grid state.

[0181] As shown in FIG. 4(b), the heavily loaded Substation #1 initiates the establishment of a flexible DC interconnection system and calculates the droop no-load voltage value using the droop control formula.

[0182] V dp = V dcs - K dp ×ΔP f = 745V

[0183] V dp is the DC droop no-load voltage, V dcs is the stable operating voltage of the DC connection line (750V), K dp is the voltage source droop coefficient (-0.1).

[0184] The AC / DC converter of Substation #1 is switched to a voltage source in the working droop mode, the AC switch QF1 and the DC switch QD1 are closed, and the flexible DC interconnection system (the establishment of the DC connection line voltage represents the establishment of the flexible DC interconnection system). Since there is no power transfer between the power distribution areas at this time, the DC connection line voltage (the real-time voltage at the lower port of the DC circuit breaker) V dc is equal to the droop voltage of the converter valve,

[0185] V dc = V dp = 745V

[0186] As shown in FIG. 4(c), the lightly loaded Substation #3 monitors the underpower state of the system. The AC / DC converter of Substation #3 is switched to a power source in the constant power source mode, the AC switch QF3 and the DC switch QD3 are closed, and it joins the flexible DC interconnection system and issues the constant power value P adj,

[0187] P adj = ΔP qe-f = 50KW

[0188] #1 AC / DC Converter Valve P pcs = -50KW, with droop mode control,

[0189] V dc = V dp + K dp ×ΔP f = 745 - 0.1×(-50) = 750V

[0190] The flexible DC interconnected system reaches a power mutual assistance balance state.

[0191] As shown in Figure 4(d), the #2 substation area changes from a light load state to a heavy load state, and the power deficit of the substation transformer is ΔP qe-t ,

[0192] ΔP qe-t = P e - P load = 250 - 300 = -50KW

[0193] As shown in Figure 4(e), the #2 heavy load substation area monitors the system power balance state. The #2 AC / DC converter switches to a constant power source mode power source, closes the AC switch QF2 and the DC switch QD2, joins the flexible DC interconnected system, and issues the constant power value P for power transfer adj ,

[0194] P adj = ΔP qe-t = -50KW

[0195] #1 AC / DC Converter Valve P pcs = 0KW, with droop mode control,

[0196] V dc = V dp + K dp ×ΔP f = 745 - 0.1×0 = 745V

[0197] The flexible DC interconnected system enters a power mutual assistance imbalance state.

[0198] As shown in Figure 4(f), the #3 light load substation area monitors the system underpower state. After power regulation calculation, the constant power value P for power transfer is issued adj ,

[0199] P adj = P a ′dj +ΔP adj = 50 + 50 = 100 KW

[0200] #1 AC / DC Converter Valve P pcs = -50 KW, obtained by droop mode control,

[0201] V dc = V dp + K dp ×ΔP f = 745 - 0.1×(-50) = 750 V

[0202] The flexible DC interconnected system reaches the power mutual assistance balance state.

[0203] As shown in Figure 4(g), #2 changes from the heavy load state to the light load state, the #2 AC / DC converter switches to the long standby state, disconnects the current switch QF2 and the DC switch QD2, and exits the flexible DC interconnected system.

[0204] #1 AC / DC Converter Valve P pcs = -100 KW, obtained by droop mode control,

[0205] V dc = V dp + K dp ×ΔP f = 745 - 0.1×(-100) = 750 V

[0206] The flexible DC interconnected system enters the power mutual assistance imbalance state.

[0207] As shown in Figure 4(h), the #3 light load area monitors the system over-power state. After power regulation calculation, the constant power value P for power transfer is issued adj ,

[0208] P adj = P a ′ dj +ΔP adj = 100 - 50 = 50 KW

[0209] #1 AC / DC Converter Valve P pcs = -50 KW, obtained by droop mode control,

[0210] V dc = V dp + K dp ×ΔP f = 745 - 0.1×(-50) = 750 V

[0211] The flexible DC interconnected system reaches the power mutual assistance balance state.

[0212] As shown in Figure 4(i), #1 changes from the heavy-load state to the light-load state, and the droop no-load voltage value is calculated using the droop control formula.

[0213] V dp = V dcs - K dp ×ΔP f = 750 + 0.1×50 = 755V

[0214] #1 AC / DC converter valve P pcs = -50KW. From the droop mode control,

[0215] V dc = V dp + K dp ×ΔP f = 755 - 0.1×(-50) = 760V

[0216] The flexible DC interconnected system enters the power mutual assistance imbalance state.

[0217] As shown in Figure 4(j), the light-load area #3 monitors that the system is in an over-power state. After power regulation calculation, the constant power value P for power transfer is issued adj ,

[0218] P adj = P a ′ dj +ΔP adj = 50 - 100 = -50KW

[0219] Since P adj < 0, set P adj = 0. The #3 AC / DC converter switches to the long standby state, disconnects the current switch QF3 and the DC switch QD3, and exits the flexible DC interconnected system.

[0220] #1 AC / DC converter valve P pcs = 0KW. From the droop mode control,

[0221] V dc = V dp + K dp ×ΔP f = 755 - 0.1×0 = 755V

[0222] The flexible DC interconnected system reaches the over-power mutual assistance balance state.

[0223] As shown in Figure 4(k), the light-load area #1, acting as a voltage source, monitors that the system is in an over-power state. The DC link voltage V dc = 755V > V dcs , after a time delay Ppcs = 0, it is determined that there is no need for power mutual assistance in the substation area interval, and there is no power mutual assistance in the flexible DC interconnected system. The #1 AC / DC converter valve switches to the long standby state, and the current switch QF1 and the DC switch QD1 are disconnected, and the flexible DC interconnected system is shut down.

[0224] In the case of the transformer substation in the substation area being fully loaded, according to the real-time load of the local substation area, the droop control formula is used to calculate the droop voltage and send it to the converter valve, and the DC tie line voltage is output to establish a flexible DC interconnected system; when the system power is insufficient, the substation area in the light load state is connected to the system as a constant power mode power source; when the system power is balanced or excessive, the substation area in the heavy load state is connected to the system as a constant power mode power source; when the voltage source is in the light or heavy load state of the transformer substation, it works based on the fully loaded state of the transformer substation, and adjusts the DC tie line voltage to reflect the under-power state or over-power state of the system; the constant power mode power source in the heavy load state adjusts the constant power value of the converter valve of the local substation area according to the required compensation power size, and the constant power mode power source in the light load state adjusts the constant power value of the converter valve of the local substation area according to the DC tie line voltage size; when there is no active power flowing in or out of the AC / DC converter of the power source substation area, it exits the flexible DC interconnected system as the power source substation area; the voltage source substation area determines that there is no power mutual assistance in the flexible DC interconnected system and exits and shuts down the flexible DC interconnected system. This system does not require communication between substations, and is especially suitable for application scenarios where it is inconvenient to lay communication lines, such as long distances between substations and complex on-site environments. When there is no power mutual assistance, the substation area automatically exits the flexible DC interconnected system, and the AC / DC converter is in the long standby state, saving electricity and cost.

[0225] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the spirit and scope of the technical solutions of the present invention, and they should all be covered within the scope of the claims of the present invention.

Claims

1. A method for adaptive power mutual assistance control of flexible DC interconnection in multiple areas, characterized in that: include: Set the working mode of the converter based on the real-time load conditions of the substation; Adjust the electrical parameters of the flexible DC interconnection system based on different working modes of the converter; The electrical parameter threshold is preset, the operating state of the flexible DC interconnection system is judged based on the electrical parameter and the preset electrical parameter threshold, and the load state of the substation is dynamically adjusted based on the operating state.

2. The method for adaptive power mutual assistance control of multiple flexible DC interconnection areas according to claim 1, characterized in that: The setting of the working mode of the converter includes: If the substation is a heavy-load substation, its converter is set as a voltage source in droop mode; If the station area is a light-load or full-load station area, its converter is set as a power source in a constant power mode.

3. The method for adaptive power mutual assistance control of multiple flexible DC interconnection areas according to claim 2 is characterized in that: The electrical parameters of the flexible DC interconnection system include voltage and power. The electrical parameters of the flexible DC interconnection system adjusted based on different working modes of the converter include: The flexible DC interconnection system is established based on the voltage source in the droop mode, and the voltage of the flexible DC interconnection system is controlled by dynamically adjusting the droop voltage. The constant power mode substation automatically adjusts its output or input power according to the DC interconnection line voltage.

4. The method for adaptive power mutual assistance control of multiple flexible DC interconnection areas according to claim 3 is characterized in that: The establishment of the flexible DC interconnection system includes: When the DC tie line voltage is not greater than the first threshold, the flexible DC interconnection system is in a closed state; When the DC tie line voltage is greater than a first threshold, the flexible DC interconnection system is in an established state; If the converter valve of the substation converter is in operation and the DC switch is in the closed position, the substation is in an interconnected state; otherwise, the substation is in an off-grid state.

5. The method for adaptive power mutual assistance control of multiple flexible DC interconnection areas according to claim 4, characterized in that: Presetting the electrical parameter threshold, judging the operating state of the flexible DC interconnection system based on the electrical parameter and the preset electrical parameter threshold, and dynamically adjusting the load state of the substation based on the operating state, including: When the DC interconnection line voltage is less than a preset threshold, the power mutual assistance of the flexible DC interconnection system is insufficient; When the DC interconnection line voltage is equal to a preset threshold, the power of the flexible DC interconnection system is mutually balanced; When the DC interconnection line voltage is greater than a preset threshold, the flexible DC interconnection system has excess power mutual assistance; When the flexible DC interconnection system is in the establishment state and the power mutual aid is insufficient, if any substation is in a light-load state and is off-grid, the converter is switched to the constant power source mode according to the preset power mutual aid level, and the light-load substation provides the flexible DC interconnection system with additional power equal to the excess power of the substation to balance the system power; When the flexible DC interconnection system is in the establishment state and the power mutual aid is balanced or in excess, if any substation is in a heavy-load state and is off-grid, the converter will be switched to the constant power source mode according to the preset power mutual aid level and added to the flexible DC interconnection system. The heavy-load substation will obtain the required additional power from the flexible DC interconnection system to balance the system power. When the flexible DC interconnection system is in the establishment state and the current substation is in the interconnection state, as a voltage source in the droop mode, if the current substation is in the heavy load state or light load state, the droop voltage is dynamically adjusted according to the actual load condition of the current substation; When the flexible DC interconnection system is in the establishment state and the current substation is in the interconnection state, if the voltage source in the droop mode of the substation is in a light load state and the DC interconnection line voltage is greater than the preset threshold, the active power is determined based on the delay, and it is determined that there is no power mutual assistance demand between the substations, and the flexible DC interconnection system has no power mutual assistance. The converter of this substation is switched to the long standby state, and the AC and DC switches are disconnected to shut down the flexible DC interconnection system.

6. The method for adaptive power mutual assistance control of multiple flexible DC interconnection areas according to claim 5, characterized in that: Also includes: When the flexible DC interconnection system is in the establishment state and the power source of the area as a constant power mode is in a light load state, the constant power value is dynamically adjusted according to the power mutual assistance level setting of the area; When the flexible DC interconnection system is in the establishment state and the power source of the area as a constant power mode is in a heavy load state, the constant power value of its output is dynamically adjusted according to the power mutual assistance level setting of the area; When the flexible DC interconnection system is in the establishment state and this substation is in full load or light load state as a power source in constant power mode, if the DC interconnection line voltage is not less than the preset threshold, the active power is determined based on the delay, and it is determined that this substation does not need to participate in power mutual assistance. The converter of this substation is switched to long standby state, and the AC and DC switches are disconnected to exit the flexible DC interconnection system.

7. A multi-station flexible DC interconnection adaptive power mutual assistance control system, characterized in that: include: An operation module is used to set the working mode of the converter based on the real-time load conditions of the substation; A regulation module, used for adjusting electrical parameters of the flexible DC interconnection system based on different working modes of the converter; The control module is used to preset the electrical parameter threshold, determine the operating state of the flexible DC interconnection system based on the electrical parameter and the preset electrical parameter threshold, and dynamically adjust the load state of the substation based on the operating state.

8. The multi-station flexible DC interconnection adaptive power mutual assistance control system according to claim 7, characterized in that: The control module is used to: When the DC interconnection line voltage is less than a preset threshold, the power mutual assistance of the flexible DC interconnection system is insufficient; When the DC interconnection line voltage is equal to a preset threshold, the power of the flexible DC interconnection system is mutually balanced; When the DC interconnection line voltage is greater than a preset threshold, the flexible DC interconnection system has excess power mutual assistance; When the flexible DC interconnection system is in the establishment state and the power mutual aid is insufficient, if any substation is in a light-load state and is off-grid, the converter is switched to the constant power source mode according to the preset power mutual aid level, and the light-load substation provides the flexible DC interconnection system with additional power equal to the excess power of the substation to balance the system power; When the flexible DC interconnection system is in the establishment state and the power mutual aid is balanced or in excess, if any substation is in a heavy-load state and is off-grid, the converter will be switched to the constant power source mode according to the preset power mutual aid level and added to the flexible DC interconnection system. The heavy-load substation will obtain the required additional power from the flexible DC interconnection system to balance the system power. When the flexible DC interconnection system is in the establishment state and the current substation is in the interconnection state, as a voltage source in the droop mode, if the current substation is in the heavy load state or light load state, the droop voltage is dynamically adjusted according to the actual load condition of the current substation; When the flexible DC interconnection system is in the establishment state and the current substation is in the interconnection state, if the voltage source in the droop mode of the substation is in a light load state and the DC interconnection line voltage is greater than the preset threshold, the active power is determined based on the delay, and it is determined that there is no power mutual assistance demand between the substations, and the flexible DC interconnection system has no power mutual assistance. The converter of this substation is switched to the long standby state, and the AC and DC switches are disconnected to shut down the flexible DC interconnection system.

9. An electronic device, characterized in that: include: Memory and processor; The memory is used to store computer-executable instructions, and the processor is used to execute the computer-executable instructions. When the computer-executable instructions are executed by the processor, the steps of the multi-station flexible DC interconnection adaptive power mutual assistance control method described in any one of claims 1 to 6 are implemented.

10. A computer-readable storage medium, characterized in that: It stores computer executable instructions, which, when executed by a processor, can implement the steps of the multi-station flexible DC interconnection adaptive power mutual assistance control method as described in any one of claims 1 to 6.

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