Cooperative operation method and device of network construction type converter and static reactive power compensation device

Abstract

The embodiment of the invention provides a cooperative operation method and device for a network-forming converter and static reactive power compensation devices, and the method comprises the steps: obtaining the first rated capacity of the network-forming converter in a target region, the initial reactive power load outputted at the current time, and the first number of all static reactive power compensation devices in the target region, the second number of the static reactive power compensation devices participating in replacement and the second rated capacity of each static reactive power compensation device are determined, and the rated capacities of the static reactive power compensation devices are the same; according to the first rated capacity, the initial reactive load, the first number, the second number and the second rated capacity, calculating a third number of newly-added and replaced static reactive power compensation devices and replacement duration of putting each newly-added and replaced static reactive power compensation device; and according to the third number and the replacement duration, calculating the target putting time for putting each newly added and replaced static reactive power compensation device, and executing putting operation.

Description

Technical Field

[0001] The embodiments of this specification relate to the technical field of grid-connected energy processing, and particularly to a collaborative operation method and device for a grid-forming converter and a static var compensator. Background Art

[0002] Reactive power compensation technology is an important means to maintain voltage stability, reduce transmission losses, and optimize system operation in the power system. Static var compensators such as shunt capacitors and shunt reactors have a large delay due to their switching characteristics, which determines that they cannot provide flexible and sufficient dynamic reactive power support to the power grid under AC-DC fault conditions. Dynamic var compensators such as static var generators (SVG) based on grid-following (GFL) converters are widely used in the power generation side and load side of new energy (such as wind energy and photovoltaic) because they instantaneously respond to the voltage changes of the power system to increase or decrease reactive power output. However, grid-following converters are prone to sub-high-frequency oscillations in a high-proportion new energy power grid. The SVG based on grid-forming (GFM) converters has a fast response speed and can effectively suppress system oscillations, and will be widely used in high-proportion new energy power grids in the future.

[0003] With the increase in the access scale of new energy, the demand for reactive power compensation and technological development show significant trends and challenges. Due to the volatility and intermittency of new energy power generation, the voltage at its access point fluctuates frequently. At the same time, new energy access usually occurs in areas far from the main grid, and the insufficient short-circuit capacity makes the system's dependence on dynamic reactive power support increase significantly. To ensure sufficient dynamic reactive power support during faults, the use of grid-forming converters and static var compensators should be reasonably allocated during steady state. Under normal steady-state conditions, the grid-forming converter retains its reactive power output capacity as an accident standby resource to enhance the dynamic regulation margin of the power grid. At the same time, static var compensators are preferentially put into use to undertake the reactive power demand during steady-state operation, thereby reducing the continuous operation pressure of the grid-forming converter. However, existing research has a trade-off problem between dynamic response speed and static resource utilization efficiency, and it is difficult to meet the requirements of modern power systems for efficient and stable voltage support. A collaborative optimization strategy is needed to achieve a reasonable allocation of dynamic and static reactive power resources in the time and space scales. Summary of the Invention

[0004] In view of this, the embodiments of this specification provide a collaborative operation method for a grid-forming converter and a static var compensator. One or more embodiments of this specification simultaneously relate to a collaborative operation device for a grid-forming converter and a static var compensator, a computing device, a computer-readable storage medium, and a computer program to solve the technical defects existing in the prior art.

[0005] According to the first aspect of the embodiments of the present specification, a collaborative operation method for a network-forming converter and a static var compensator is provided, including:

[0006] Obtain the first rated capacity of the network-forming converter in the target area, the initial reactive power load output at the current time, the first quantity of all static var compensators in the target area, the second quantity of the static var compensators that have participated in the replacement, and the second rated capacity of each static var compensator, where the rated capacity of each static var compensator is the same;

[0007] Calculate the third quantity of the newly added static var compensators to be replaced, and the replacement duration for each newly added static var compensator to be replaced, according to the first rated capacity, the initial reactive power load, the first quantity, the second quantity, and the second rated capacity;

[0008] Calculate the target delivery time for each newly added static var compensator to be replaced and perform the delivery operation according to the third quantity and the replacement duration.

[0009] In some embodiments, the step of calculating the third quantity of the newly added static var compensators to be replaced includes:

[0010] Judge whether the initial reactive power load is greater than the first rated capacity;

[0011] In the case where the initial reactive power load is greater than the first rated capacity, determine the first rated capacity as the total dynamic amount to be reduced;

[0012] In the case where the initial reactive power load is not greater than the first rated capacity, determine the initial reactive power load as the total dynamic amount to be reduced;

[0013] Calculate the third quantity according to the total dynamic amount to be reduced, the first quantity, the second quantity, and the second rated capacity.

[0014] In some embodiments, calculating the third quantity according to the total dynamic amount to be reduced, the first quantity, the second quantity, and the second rated capacity includes:

[0015] Obtain the central voltage of the voltage central point in the target area, the voltage influence coefficient during the replacement of the static var compensator, the balanced voltage and balanced reactive power of the power grid system;

[0016] Calculate the total static amount to be invested according to the second quantity and the second rated capacity;

[0017] Calculate the third quantity according to the total dynamic amount to be reduced, the first quantity, the second quantity, the second rated capacity, the total static amount to be invested, the central voltage, the voltage influence coefficient, the balanced voltage, and the balanced reactive power.

[0018] In some embodiments, calculating a third quantity based on a dynamic total amount to be subtracted, a first quantity, a second quantity, a second rated capacity, a static total amount to be invested, a central voltage, a voltage influence coefficient, a balanced voltage, and a balanced reactive power includes:

[0019] When the dynamic total reactive power to be invested is greater than the static total amount to be invested, determining the difference between the first quantity and the second quantity as the third quantity;

[0020] When the dynamic total reactive power to be invested is not greater than the static total amount to be invested, determining the quotient of the dynamic total amount to be subtracted divided by the second rated capacity as the third quantity;

[0021] Among them, the static total amount to be invested, the central voltage, the voltage influence coefficient, the balanced voltage, and the balanced reactive power meet the requirements of a preset first calculation formula.

[0022] In some embodiments, the first calculation formula includes:

[0023] Q e =(N - n c )Q C

[0024] |Q e -Q AC |≤Q ref

[0025] U+(N - n C )wQ C ≤U ref

[0026] Among them, Qe represents the static total amount to be invested, N represents the first quantity, n c represents the second quantity, Q C represents the second rated capacity, Q ref represents the balanced reactive power, U represents the central voltage, w represents the point - smoke influence coefficient, U ref represents the balanced voltage.

[0027] In some embodiments, calculating the replacement duration for each newly added replaced static reactive power compensation device is obtained by calculating based on the obtained placement duration and margin duration of each reactive power compensation device.

[0028] In some embodiments, calculating the target placement time for each static reactive power compensation device with a newly added replacement according to the third quantity and the replacement duration includes:

[0029] Calculating the target placement time for each static reactive power compensation device with a newly added replacement according to the third quantity, the replacement duration, and a preset second calculation formula, where the second calculation formula includes:

[0030]

[0031] where t si represents the time when the i-th newly added and replaced static var compensator is put into operation, M represents the third quantity, i represents the sequence value of the newly added and replaced static var compensators put into operation, and t pin represents the replacement duration.

[0032] In some embodiments, it further includes:

[0033] Calculating the total replacement duration of all newly added and replaced static var compensators according to the third quantity and the replacement duration;

[0034] Calculating the decreasing rate of the reactive power output of the network-forming converter according to the total replacement duration and the initial reactive power load;

[0035] Performing simulation display based on the total replacement duration and the decreasing rate.

[0036] According to the second aspect of the embodiments of the present specification, a coordinated operation device for a network-forming converter and a static var compensator is provided, including:

[0037] An acquisition module, configured to acquire the first rated capacity of the network-forming converter in the target area, the initial reactive power load output at the current time, the first quantity of all static var compensators in the target area, the second quantity of the static var compensators that have participated in the replacement, and the second rated capacity of each static var compensator, where the rated capacity of each static var compensator is the same;

[0038] A first calculation module, configured to calculate the third quantity of the newly added and replaced static var compensators, and the replacement duration for putting each newly added and replaced static var compensator into operation according to the first rated capacity, the initial reactive power load, the first quantity, the second quantity, and the second rated capacity;

[0039] A second calculation module, configured to calculate the target putting time of each newly added and replaced static var compensator according to the third quantity and the replacement duration and perform the putting operation.

[0040] In some embodiments, the step of calculating the third quantity of the newly added and replaced static var compensators includes:

[0041] Judging whether the initial reactive power load is greater than the first rated capacity;

[0042] When the initial reactive power load is greater than the first rated capacity, determining the first rated capacity as the dynamic total amount to be reduced;

[0043] When the initial reactive power load is not greater than the first rated capacity, determining the initial reactive power load as the dynamic total amount to be reduced;

[0044] Calculate a third quantity based on the total amount to be reduced dynamically, a first quantity, a second quantity, and a second rated capacity.

[0045] In some embodiments, calculating a third quantity based on the total amount to be reduced dynamically, a first quantity, a second quantity, and a second rated capacity includes:

[0046] Obtain the central voltage of the voltage central point in the target area, the voltage influence coefficient during the replacement of the static var compensator, the balanced voltage and the balanced reactive power of the power grid system;

[0047] Calculate the total static amount to be invested according to the second quantity and the second rated capacity;

[0048] Calculate a third quantity based on the total amount to be reduced dynamically, a first quantity, a second quantity, a second rated capacity, the total static amount to be invested, the central voltage, the voltage influence coefficient, the balanced voltage, and the balanced reactive power.

[0049] In some embodiments, calculating a third quantity based on the total amount to be reduced dynamically, a first quantity, a second quantity, a second rated capacity, the total static amount to be invested, the central voltage, the voltage influence coefficient, the balanced voltage, and the balanced reactive power includes:

[0050] When the total dynamic reactive power to be invested is greater than the total static amount to be invested, determine the difference between the first quantity and the second quantity as the third quantity;

[0051] When the total dynamic reactive power to be invested is not greater than the total static amount to be invested, determine the quotient of the total amount to be reduced dynamically divided by the second rated capacity as the third quantity;

[0052] Wherein, the total static amount to be invested, the central voltage, the voltage influence coefficient, the balanced voltage, and the balanced reactive power meet the requirements of a preset first calculation formula.

[0053] In some embodiments, the first calculation formula includes:

[0054] Q e =(N - n c )Q C

[0055] |Q e - Q AC |≤Q ref

[0056] U+(N - n C )wQ C ≤U ref

[0057] Wherein, Qe represents the total static amount to be invested, N represents the first quantity, n c represents the second quantity, Q C represents the second rated capacity, Q refQ represents the balanced reactive power, U represents the central voltage, w represents the influence coefficient of the ignition, and U ref represents the balanced voltage.

[0058] In some embodiments, the replacement duration for each newly added replacement static var compensator is calculated based on the obtained placement duration and margin duration of each var compensator.

[0059] In some embodiments, according to the third quantity and the replacement duration, calculating the target placement time for each static var compensator with a newly added replacement includes:

[0060] According to the third quantity, the replacement duration, and a preset second calculation formula, calculate the target placement time for each static var compensator with a newly added replacement, where the second calculation formula includes:

[0061]

[0062] where t si represents the time of the i-th static var compensator with a newly added replacement, M represents the third quantity, i represents the sequence value of the static var compensator with a newly added replacement, and t pin represents the replacement duration.

[0063] In some embodiments, the coordinated operation device of the network-forming converter and the static var compensator further includes a simulation display module, and the simulation display module is configured to: calculate the total replacement duration of all newly added replacement static var compensators according to the third quantity and the replacement duration; calculate the decreasing rate of the reactive power output of the network-forming converter according to the total replacement duration and the initial reactive load; and perform a simulation display based on the total replacement duration and the decreasing rate.

[0064] According to the third aspect of the embodiments of the present specification, there is provided a computing device, including:

[0065] a memory and a processor;

[0066] 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 above-mentioned coordinated operation method of the network-forming converter and the static var compensator are implemented.

[0067] According to the fourth aspect of the embodiments of the present specification, there is provided a computer-readable storage medium, which stores computer-executable instructions. When the instructions are executed by the processor, the steps of the above-mentioned coordinated operation method of the network-forming converter and the static var compensator are implemented.

[0068] According to a fifth aspect of the embodiments of the present specification, a computer program is provided, wherein when the computer program is executed in a computer, the computer is made to execute the steps of the above-mentioned cooperative operation method of the network-forming converter and the static var compensator.

[0069] In at least one embodiment of the embodiments of the present specification, by obtaining the first rated capacity of the network-forming converter in the target area, the initial reactive power load output at the current time, the first quantity of all static var compensators in the target area, the second quantity of the static var compensators that have participated in the replacement, and the second rated capacity of each static var compensator, wherein the rated capacity of each static var compensator is the same; calculating the third quantity of the newly added replaced static var compensators and the replacement duration of each newly added replaced static var compensator according to the first rated capacity, the initial reactive power load, the first quantity, the second quantity, and the second rated capacity; calculating the target placement time of each newly added replaced static var compensator according to the third quantity and the replacement duration and performing the placement operation. On the one hand, the static reactive power resources are used to replace the dynamic reactive power resources, so as to make full use of the transient voltage support performance of the network-forming converter, effectively suppress the fault voltage drop phenomenon of the new energy unit when a fault occurs, and reduce the load of the network-forming converter to improve the service life and ensure the long-term stable operation of the system. On the other hand, based on the accurate switching moment (target placement time) to perform switching, the reactive power compensation effect of the new energy grid-connected system can be improved, and the reactive power fluctuation at the switching moment can be reduced. Description of the Drawings

[0070] Figure 1 is a flowchart of some embodiments of a cooperative operation method of a network-forming converter and a static var compensator provided by some embodiments of the present specification;

[0071] Figure 2 is provided by some embodiments of the present specification Figure 1 a flowchart of the detailed steps of step 102 therein;

[0072] Figure 3 is a comparison schematic diagram of the reactive power fluctuations between a cooperative operation method of a network-forming converter and a static var compensator provided by some embodiments of the present specification and a conventional method;

[0073] Figure 4 is a comparison schematic diagram of the voltage fluctuations between a cooperative operation method of a network-forming converter and a static var compensator provided by some embodiments of the present specification and a conventional method;

[0074] Figure 5 is a flowchart of some other embodiments of a cooperative operation method of a network-forming converter and a static var compensator provided by some embodiments of the present specification;

[0075] Figure 6 It is a simplified structural schematic diagram of a coordinated operation device of a grid-forming converter and a static var compensator provided by some embodiments of this specification;

[0076] Figure 7 It is a structural block diagram of a computing device provided by some embodiments of this specification. Specific embodiments

[0077] In the following description, many specific details are set forth in order to provide a thorough understanding of this specification. However, this specification can be implemented in many other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the connotation of this specification. Therefore, this specification is not limited by the specific embodiments disclosed below.

[0078] The terms used in one or more embodiments of this specification are for the purpose of describing specific embodiments only and are not intended to limit one or more embodiments of this specification. The singular forms "a" and "the" used in one or more embodiments of this specification and the appended claims are also intended to include the plural forms unless the context clearly dictates otherwise. It should also be understood that the term "and / or" used in one or more embodiments of this specification refers to and includes any or all possible combinations of one or more of the associated listed items. The modifiers "a" and "multiple" mentioned in this disclosure are illustrative rather than restrictive, and those skilled in the art should understand that unless clearly specified otherwise in the context, it should be understood as "one or more".

[0079] It should be understood that although the terms first, second, etc. may be used in one or more embodiments of this specification to describe various information, such information should not be limited to these terms. These terms are only used to distinguish information of the same type from each other. For example, without departing from the scope of one or more embodiments of this specification, the first may also be referred to as the second, and similarly, the second may also be referred to as the first. Depending on the context, the word "if" as used herein may be interpreted as "when" or "while" or "in response to determining".

[0080] The synergy among reactive power sources is mainly reflected in the collaborative cooperation in the spatio-temporal dimension. The network-forming converter can respond instantaneously to the change of system voltage and has the reactive power output ability in the millisecond level, so it can play a major role in the transient voltage support stage; while static reactive power compensation devices such as reactors and capacitors have a relatively slow switching speed and can only play an effective role in the steady-state voltage support stage. Based on this, the collaborative optimization strategy among reactive power sources can be reasonably planned. Under steady-state conditions, static reactive power resources can be used to replace dynamic reactive power resources to make full use of the transient voltage support performance of the network-forming converter, effectively suppress the fault voltage drop of new energy units during faults, and ensure the stable operation of the system.

[0081] See Figure 1 , Figure 1 Fig. shows a flowchart of a collaborative operation method of a network-forming converter and a static reactive power compensation device according to some embodiments of the present specification, which specifically includes the following steps.

[0082] Step 101: Obtain the first rated capacity of the network-forming converter in the target area, the initial reactive power load output at the current time, the first quantity of all static reactive power compensation devices in the target area, the second quantity of static reactive power compensation devices that have participated in the replacement, and the second rated capacity of each static reactive power compensation device.

[0083] In the actual operation process, 1 network-forming converter can be set in the target area to adjust reactive power quickly in real time. At the same time, multiple static reactive power compensation devices (or a group of static reactive power compensation devices, and the following static reactive power compensation devices all correspond to a single or a single group) can be set. When there is a continuous reactive power load in the network-forming converter, static reactive power compensation devices need to be put into use for replacement to reduce the reactive power load of the network-forming converter, thereby improving the service life of the network-forming converter. In addition, when in the following situations, the static reactive power compensation devices can be cut out to reduce the equipment switching loss and the risk of dielectric aging and improve the overall energy efficiency:

[0084] Situation 1: When the network-forming converter is in a 0-load state for a long time and the system reactive power demand is stable.

[0085] Situation 2: When the user-side load demand changes and causes the voltage level to be too high.

[0086] Situation 3: When in the light-load stage at night, the line charging capacitance effect is significant and the voltage level is high.

[0087] The operation details of cutting out the static reactive power compensation equipment are prior art and will not be elaborated here.

[0088] In some embodiments, in order to calculate various parameters when a network-forming converter and a static var compensator operate in coordination for execution of connection or disconnection, it is necessary to first obtain the first rated capacity of the network-forming converter in the target area, the initial reactive power load output at the current time, the first quantity of all static var compensators in the target area, the second quantity of static var compensators that have participated in replacement, and the second rated capacity of each static var compensator. The first rated capacity may refer to the rated reactive power capacity of the network-forming converter in the operating state. The second rated capacity may refer to the rated reactive power capacity of the static var compensator in the operating state. When there is a load on the network-forming converter, it indicates that the reactive power capacity of the currently connected static var compensators cannot carry the reactive power of the power grid. Therefore, more static var compensators need to be added. The first quantity may refer to the quantity of all static var compensators in the target area. The second quantity may refer to the quantity of static var compensators that have been put into use.

[0089] Since the actual operating capacity of a network-forming converter during operation may be greater than its rated capacity. For example, certain models of network-forming converters allow short-term overload of 10% to 50% (generally within a few seconds), and long-term operation needs to be limited within 105% - 110% of the rated value, depending on the material, factory settings, and other relevant content of each converter. The initial reactive power load may refer to the actual reactive power load of the network-forming converter during operation. As an example, assume that the rated power of the reactive power of network-forming converter A is 200 kW, then its reactive power load during normal operation can be 0 to 210 kW for long-term operation, and occasionally can operate up to 300 kW for short-term operation.

[0090] Step 102: Calculate the third quantity of newly replaced static var compensators and the replacement duration for each newly replaced static var compensator according to the first rated capacity, the initial reactive power load, the first quantity, the second quantity, and the second rated capacity.

[0091] In some embodiments, the step of calculating the third quantity of newly replaced static var compensators may include the following steps as Figure 2 shown:

[0092] Step 1021: Determine whether the initial reactive power load is greater than the first rated capacity.

[0093] As can be seen from the foregoing, the initial reactive power load may be greater than its rated capacity. Therefore, when the network-forming converter has a load, it is necessary to first determine whether its initial reactive power load is greater than the rated capacity, and then adopt different calculation methods to calculate the third quantity for different situations.

[0094] Step 1022: When the initial reactive power load is greater than the first rated capacity, determine the first rated capacity as the dynamic total to be subtracted.

[0095] Step 1023: When the initial reactive power load is not greater than the first rated capacity, determine the initial reactive power load as the total amount to be dynamically reduced.

[0096] The total amount to be dynamically reduced may refer to the total amount of reactive power that the grid-forming converter expects to reduce. Since the grid-forming converter can often only operate for a short period of time when it exceeds the load, if the calculation is based on the load that exceeds the rated capacity, the accuracy of the calculation result will decrease after a short time, which may lead to too many static var compensators and large reactive power fluctuations.

[0097] In some embodiments, when the initial reactive power load is greater than the first rated capacity, determine the first rated capacity as the total amount to be dynamically reduced. In other embodiments, when the initial reactive power load is not greater than the first rated capacity, determine the initial reactive power load as the total amount to be dynamically reduced.

[0098] Step 1024: Calculate the third quantity according to the total amount to be dynamically reduced, the first quantity, the second quantity, and the second rated capacity.

[0099] In some alternative implementation manners, the third quantity can be calculated according to the total amount to be dynamically reduced, the first quantity, the second quantity, and the second rated capacity through the following steps:

[0100] First step, obtain the central voltage of the voltage central point in the target area, the voltage influence coefficient when replacing the static var compensator, the balanced voltage of the power grid system, and the balanced reactive power. The central voltage, the voltage influence coefficient, the balanced voltage, and the balanced reactive power are conventional parameters in the art and will not be elaborated here. The above parameters are used to limit the range of the total amount of static var compensators to be put into operation in the subsequent steps, reduce the reactive power fluctuations when putting into operation the static var compensators, and further enhance the stability when putting into operation the static var compensators.

[0101] Second step, calculate the total amount of static var compensators to be put into operation according to the second quantity and the second rated capacity. The total amount of static var compensators to be put into operation may refer to the sum of the reactive power capacitors of all the var compensators that have not been put into operation. Obviously, the product of the second quantity and the second rated capacity is the total amount of static var compensators to be put into operation.

[0102] Step 3: Calculate the third quantity based on the dynamic total amount to be subtracted, the first quantity, the second quantity, the second rated capacity, the static total amount to be invested, the central voltage, the voltage influence coefficient, the balance voltage, and the balance reactive power. This step can be further decomposed as follows: When the dynamic total reactive power to be invested is greater than the static total amount to be invested, the difference between the first quantity and the second quantity is determined as the third quantity. When the dynamic total reactive power to be invested is not greater than the static total amount to be invested, the quotient of the dynamic total amount to be subtracted divided by the second rated capacity is determined as the third quantity. Among them, the static total amount to be invested, the central voltage, the voltage influence coefficient, the balance voltage, and the balance reactive power meet the requirements of a preset first calculation formula.

[0103] The first calculation formula includes:

[0104] Q e =(N - n c )Q C

[0105] |Q e - Q AC | ≤ Q ref

[0106] U + (N - n C )wQ C ≤ U ref

[0107] Among them, Qe represents the static total amount to be invested, N represents the first quantity, n c represents the second quantity, Q C represents the second rated capacity, Q ref represents the balance reactive power, U represents the central voltage, w represents the point smoke influence coefficient, U ref represents the balance voltage.

[0108] By restricting the static total amount to be invested through the first calculation formula and calculating the third quantity through the above method, the third quantity of the static reactive power compensation device to be placed can be obtained accurately.

[0109] The replacement duration of the newly added replacement static reactive power compensation device can refer to the total sum of all the time required for this static reactive power compensation device to be put into the power grid system. Usually during the placement, a preset automatic switching device is used to perform placement / cutting out for each static reactive power compensation device that needs to be newly added and replaced, so there will be a placement duration. In addition, the existence of delays caused by various reasons in the system also needs to be considered, so a margin time, that is, a margin duration, also needs to be set.

[0110] In some alternative implementation manners, the replacement duration for placing each newly added replacement static reactive power compensation device is calculated based on the obtained placement duration and margin duration of each reactive power compensation device.

[0111] Step 103: Calculate the target deployment time for each newly deployed static var compensator according to the third quantity and the replacement duration, and perform the deployment operation.

[0112] The target deployment time can refer to the specific time point for starting to deploy each newly replaced static var compensator calculated based on the target time base point. If it is set to deploy the first capacitor bank after the reactive power load of the grid-forming converter has decreased by one capacitor bank capacity, the impact on the system is B. Analysis shows that when the output of the grid-forming converter drops to 0.5B and the capacitor bank is deployed, the reactive power impact on the reactive power partition during the reactive power replacement process can be minimized. At this time, the reactive power impact on the reactive power partition caused by each reactive power replacement process is only 0.5B, which helps to significantly improve the voltage stability during the replacement process. In order to more effectively reduce the reactive power impact on the reactive power partition during the replacement process and thus ensure the reactive power balance and voltage stability of the power system to the greatest extent, it is necessary to accurately determine the instantaneous moment of capacitor bank switching, so as to ensure that the reactive power deficit or surplus during the replacement process can be minimized and the reactive power fluctuation of the system can be reduced.

[0113] In some embodiments, calculating the target deployment time for each newly deployed static var compensator according to the third quantity and the replacement duration includes:

[0114] Calculating the target deployment time for each newly deployed static var compensator according to the third quantity, the replacement duration, and a preset second calculation formula, where the second calculation formula includes:

[0115]

[0116] where t si represents the time of the i-th newly deployed static var compensator, M represents the third quantity, i represents the sequence value of the newly deployed static var compensator, and t pin represents the replacement duration.

[0117] The beneficial effects of one of the embodiments in this specification at least include: by obtaining the first rated capacity of the grid-forming converter in the target area, the initial reactive power load output at the current time, the first quantity of all static var compensators in the target area, the second quantity of the static var compensators that have participated in the replacement, and the second rated capacity of each static var compensator, where the rated capacity of each static var compensator is the same; calculating the third quantity of the newly added static var compensators for replacement and the replacement duration for each newly added static var compensator to be put into use according to the first rated capacity, the initial reactive power load, the first quantity, the second quantity, and the second rated capacity; calculating the target delivery time for each newly added static var compensator to be put into use and performing the delivery operation according to the third quantity and the replacement duration. On the one hand, the static reactive power resources are used to replace the dynamic reactive power resources, so as to make full use of the transient voltage support performance of the grid-forming converter, effectively suppress the fault voltage drop phenomenon of the new energy unit when a fault occurs, and reduce the load of the grid-forming converter to extend its service life and ensure the long-term stable operation of the system. On the other hand, based on the precise switching moment (target delivery time) for switching, the reactive power compensation effect of the new energy grid-connected system can be improved, and the reactive power fluctuation at the switching moment can be reduced.

[0118] In some embodiments, the method for the coordinated operation of the grid-forming converter and the static var compensator further includes: calculating the total replacement duration of all the newly added static var compensators for replacement according to the third quantity and the replacement duration; calculating the decreasing rate of the reactive power output of the grid-forming converter according to the total replacement duration and the initial reactive power load; and performing a simulation display based on the total replacement duration and the decreasing rate.

[0119] Through the simulation display, the differences between the embodiments of the present invention and the ordinary processing methods can be obtained. As Figure 3 and Figure 4 shown, Figure 3 shows a schematic diagram of the difference in reactive power fluctuation between the processing by the embodiments of the present invention (the precise switching moment in the figure corresponds to the target delivery time in the embodiments of this specification, Figure 4 similarly) and the ordinary processing method. Figure 4 shows a schematic diagram of the difference in voltage fluctuation between the processing by the embodiments of the present invention and the ordinary processing method. It can be seen that both the reactive power fluctuation and the voltage fluctuation processed by the embodiments of this specification are significantly reduced.

[0120] The following combines the attached Figure 5 , taking the application of the method for the coordinated operation of the grid-forming converter and the static var compensator provided in this specification in 00000 as an example, to further illustrate the method for the coordinated operation of the grid-forming converter and the static var compensator. Among them, Figure 5The flowchart of the processing procedure of a cooperative operation method for a network-forming converter and a static var compensator provided by some embodiments of this specification is shown, which specifically includes the following steps.

[0121] Step 501: Obtain the first rated capacity of the network-forming converter in the target area, the initial reactive power load output at the current time, the first quantity of all static var compensators in the target area, the second quantity of the static var compensators that have participated in the replacement, and the second rated capacity of each static var compensator.

[0122] Step 502: Calculate the third quantity of the newly added replaced static var compensators according to the first rated capacity, the initial reactive power load, the first quantity, the second quantity, and the second rated capacity.

[0123] Step 503: Determine whether the initial reactive power load is greater than the first rated capacity.

[0124] Step 504: When the initial reactive power load is greater than the first rated capacity, determine the first rated capacity as the total dynamic amount to be reduced.

[0125] Step 505: When the initial reactive power load is not greater than the first rated capacity, determine the initial reactive power load as the total dynamic amount to be reduced.

[0126] Step 506: Obtain the central voltage of the voltage central point in the target area, the voltage influence coefficient during the replacement of the static var compensator, the balanced voltage and the balanced reactive power of the power grid system.

[0127] Step 507: Calculate the total static amount to be put into operation according to the second quantity and the second rated capacity. Among them, the total static amount to be put into operation, the central voltage, the voltage influence coefficient, the balanced voltage, and the balanced reactive power meet the requirements of a preset first calculation formula.

[0128] Step 508: When the total dynamic reactive power amount to be put into operation is greater than the total static amount to be put into operation, determine the difference between the first quantity and the second quantity as the third quantity.

[0129] Step 509: When the total dynamic reactive power amount to be put into operation is not greater than the total static amount to be put into operation, determine the quotient of the total dynamic amount to be reduced divided by the second rated capacity as the third quantity.

[0130] Step 510: Calculate the replacement duration of each newly added replaced static var compensator according to the obtained placement duration and margin duration of each var compensator.

[0131] Step 511: Calculate the target placement time of each newly added replaced static var compensator according to the third quantity and the replacement duration, and perform the placement operation.

[0132] In some embodiments, steps 501 - 511Figure 1 For the specific implementation of the corresponding steps in the corresponding embodiments and the resulting technical effects, reference can be made to Figure 1 the steps therein, which will not be elaborated here.

[0133] Corresponding to the above method embodiments, this specification also provides embodiments of a coordinated operation device for a network-forming converter and a static var compensator. Figure 6 FIG. shows a schematic structural diagram of a coordinated operation device for a network-forming converter and a static var compensator provided by some embodiments of this specification. As Figure 6 shown, the device includes:

[0134] An acquisition module 601, configured to acquire the first rated capacity of the network-forming converter in the target area, the initial reactive power load output at the current time, the first quantity of all static var compensators in the target area, the second quantity of the static var compensators that have participated in the replacement, and the second rated capacity of each static var compensator, where the rated capacity of each static var compensator is the same;

[0135] A first calculation module 602, configured to calculate the third quantity of the newly added replaced static var compensators and the replacement duration for each newly added replaced static var compensator according to the first rated capacity, the initial reactive power load, the first quantity, the second quantity, and the second rated capacity;

[0136] A second calculation module 603, configured to calculate the target placement time for each newly added replaced static var compensator and perform the placement operation according to the third quantity and the replacement duration.

[0137] In some embodiments, the step of calculating the third quantity of the newly added replaced static var compensators includes:

[0138] Determine whether the initial reactive power load is greater than the first rated capacity;

[0139] In the case where the initial reactive power load is greater than the first rated capacity, determine the first rated capacity as the dynamic total to be reduced;

[0140] In the case where the initial reactive power load is not greater than the first rated capacity, determine the initial reactive power load as the dynamic total to be reduced;

[0141] Calculate the third quantity according to the dynamic total to be reduced, the first quantity, the second quantity, and the second rated capacity.

[0142] In some embodiments, calculating the third quantity according to the dynamic total to be reduced, the first quantity, the second quantity, and the second rated capacity includes:

[0143] Obtain the central voltage of the voltage central point within the target area, the voltage influence coefficient when replacing the static var compensator, the balanced voltage and balanced reactive power of the power grid system;

[0144] Calculate the total static investment to be put in according to the second quantity and the second rated capacity;

[0145] Calculate the third quantity according to the total dynamic reduction amount, the first quantity, the second quantity, the second rated capacity, the total static investment to be put in, the central voltage, the voltage influence coefficient, the balanced voltage and the balanced reactive power.

[0146] In some embodiments, calculating the third quantity according to the total dynamic reduction amount, the first quantity, the second quantity, the second rated capacity, the total static investment to be put in, the central voltage, the voltage influence coefficient, the balanced voltage and the balanced reactive power includes:

[0147] When the total dynamic reactive power to be put in is greater than the total static investment to be put in, determine the difference between the first quantity and the second quantity as the third quantity;

[0148] When the total dynamic reactive power to be put in is not greater than the total static investment to be put in, determine the quotient of the total dynamic reduction amount divided by the second rated capacity as the third quantity;

[0149] Among them, the total static investment to be put in, the central voltage, the voltage influence coefficient, the balanced voltage and the balanced reactive power meet the requirements of a preset first calculation formula.

[0150] In some embodiments, the first calculation formula includes:

[0151] Q e =(N - n c )Q C

[0152] |Q e -Q AC |≤Q ref

[0153] U+(N - n C )wQ C ≤U ref

[0154] Among them, Qe represents the total static investment to be put in, N represents the first quantity, n c represents the second quantity, Q C represents the second rated capacity, Q ref represents the balanced reactive power, U represents the central voltage, w represents the point smoke influence coefficient, U ref represents the balanced voltage.

[0155] In some embodiments, the replacement duration of each newly added static var compensator is calculated based on the obtained placement duration and margin duration of each var compensator.

[0156] In some embodiments, according to the third quantity and the replacement duration, calculating the target placement time of each static var compensator for newly added replacement includes:

[0157] According to the third quantity, the replacement duration, and a preset second calculation formula, calculating the target placement time of each static var compensator for newly added replacement, where the second calculation formula includes:

[0158]

[0159] where t si represents the time of the i-th static var compensator for newly added replacement, M represents the third quantity, i represents the sequence value of the newly added replacement static var compensators, and t pin represents the replacement duration.

[0160] In some embodiments, the coordinated operation device of the network-forming converter and the static var compensator further includes a simulation display module, and the simulation display module is configured to: calculate the total replacement duration of all newly added replacement static var compensators according to the third quantity and the replacement duration; calculate the decreasing rate of the reactive power output of the network-forming converter according to the total replacement duration and the initial reactive power load; and perform simulation display based on the total replacement duration and the decreasing rate.

[0161] The above is a schematic solution of a coordinated operation device of a network-forming converter and a static var compensator in this embodiment. It should be noted that the technical solution of this coordinated operation device of the network-forming converter and the static var compensator belongs to the same concept as the above technical solution of the coordinated operation method of the network-forming converter and the static var compensator. For the details not described in the technical solution of this coordinated operation device of the network-forming converter and the static var compensator, reference can be made to the description of the technical solution of the above coordinated operation method of the network-forming converter and the static var compensator.

[0162] Figure 7 FIG. shows a structural block diagram of a computing device 700 according to some embodiments of the present specification. The components of the computing device 700 include, but are not limited to, a memory 701 and a processor 702. The processor 702 is connected to the memory 701 through a bus 703, and a database 705 is used to store data.

[0163] The computing device 700 also includes an access device 704 that enables the computing device 700 to communicate via one or more networks 706. Examples of such networks include the Public Switched Telephone Network (PSTN), Local Area Network (LAN), Wide Area Network (WAN), Personal Area Network (PAN), or a combination of communication networks such as the Internet. The access device 704 may include one or more of any type of wired or wireless network interface (e.g., network interface controller (NIC)), such as an IEEE 802.11 Wireless Local Area Network (WLAN) wireless interface, Worldwide Interoperability for Microwave Access (Wi-MAX) interface, Ethernet interface, Universal Serial Bus (USB) interface, cellular network interface, Bluetooth interface, Near Field Communication (NFC).

[0164] In one embodiment of the present specification, the above components of the computing device 700, as well as Figure 4 other components not shown, may also be connected to each other, for example, via a bus. It should be understood that Figure 4 the block diagram of the computing device shown is for illustrative purposes only and is not a limitation on the scope of the present specification. Those skilled in the art may add or replace other components as needed.

[0165] The computing device 700 can be any type of stationary or mobile computing device, including mobile computers or mobile computing devices (e.g., tablet computers, personal digital assistants, laptop computers, notebook computers, netbooks, etc.), mobile phones (e.g., smartphones), wearable computing devices (e.g., smartwatches, smart glasses, etc.), or other types of mobile devices, or stationary computing devices such as desktop computers or personal computers (PCs). The computing device 700 can also be a mobile or stationary server.

[0166] Among them, the processor 702 is configured to execute the following computer-executable instructions. When the computer-executable instructions are executed by the processor, the steps of the above-mentioned collaborative operation method of the network-forming converter and the static var compensator are implemented. The above is a schematic solution of a computing device according to this embodiment. It should be noted that the technical solution of this computing device and the technical solution of the above-mentioned collaborative operation method of the network-forming converter and the static var compensator belong to the same concept. For the details not described in detail in the technical solution of the computing device, reference can be made to the description of the technical solution of the above-mentioned collaborative operation method of the network-forming converter and the static var compensator.

[0167] An embodiment of this specification also provides a computer-readable storage medium, which stores computer-executable instructions. When the computer-executable instructions are executed by a processor, the steps of the above-mentioned collaborative operation method of the network-forming converter and the static var compensator are implemented.

[0168] The above is a schematic solution of a computer-readable storage medium according to this embodiment. It should be noted that the technical solution of this storage medium and the technical solution of the above-mentioned collaborative operation method of the network-forming converter and the static var compensator belong to the same concept. For the details not described in detail in the technical solution of the storage medium, reference can be made to the description of the technical solution of the above-mentioned collaborative operation method of the network-forming converter and the static var compensator.

[0169] An embodiment of this specification also provides a computer program. When the computer program is executed on a computer, the computer is made to execute the steps of the above-mentioned collaborative operation method of the network-forming converter and the static var compensator.

[0170] The above is a schematic solution of a computer program according to this embodiment. It should be noted that the technical solution of this computer program and the technical solution of the above-mentioned collaborative operation method of the network-forming converter and the static var compensator belong to the same concept. For the details not described in detail in the technical solution of the computer program, reference can be made to the description of the technical solution of the above-mentioned collaborative operation method of the network-forming converter and the static var compensator.

[0171] The above describes specific embodiments of this specification. Other embodiments are within the scope of the appended claims. In some cases, the actions or steps recited in the claims may be performed in a different order than in the embodiments and still achieve the desired result. Additionally, the processes depicted in the figures do not necessarily require the particular order or sequential order shown to achieve the desired result. In certain implementations, multitasking and parallel processing are also possible or may be advantageous.

[0172] Computer instructions include computer program code, which can be in the form of source code, object code, executable files, or some intermediate forms, etc. A computer-readable medium can include: any entity or device capable of carrying computer program code, recording media, USB flash drives, external hard drives, magnetic disks, optical discs, computer memories, read-only memories (ROM), random access memories (RAM), electrical carrier signals, telecommunication signals, and software distribution media, etc. It should be noted that the content included in the computer-readable medium can be appropriately increased or decreased according to the requirements of legislation and patent practice within the jurisdiction. For example, in some jurisdictions, according to legislation and patent practice, the computer-readable medium does not include electrical carrier signals and telecommunication signals.

[0173] It should be noted that for the foregoing method embodiments, for the sake of simplicity of description, they are all expressed as a series of action combinations. However, those skilled in the art should be aware that the embodiments of this specification are not limited by the described order of actions, because according to the embodiments of this specification, certain steps can be performed in other orders or simultaneously. Secondly, those skilled in the art should also be aware that the embodiments described in the specification are all preferred embodiments, and the actions and modules involved are not necessarily essential to the embodiments of this specification.

[0174] In the above embodiments, the descriptions of the various embodiments have their own emphases. For the parts not detailed in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0175] The preferred embodiments of this specification disclosed above are only used to help explain this specification. The alternative embodiments do not elaborate on all the details, nor do they limit the invention to only the specific implementation manners. Obviously, many modifications and changes can be made according to the content of the embodiments of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the embodiments of this specification, so that those skilled in the art can well understand and utilize this specification. This specification is only limited by the claims and their full scope and equivalents.

Claims

1. A method for coordinated operation of a grid-connected converter and a static VAR compensation device, characterized in that: include: Obtaining a first rated capacity of a grid-connected converter in a target area, an initial reactive load output at a current time, a first number of all static reactive compensation devices in the target area, a second number of static reactive compensation devices that have participated in the replacement, and a second rated capacity of each of the static reactive compensation devices, wherein the rated capacity of each of the static reactive compensation devices is the same; Calculate the third number of newly replaced static reactive compensation devices and the replacement time of each newly replaced static reactive compensation device according to the first rated capacity, the initial reactive load, the first number, the second number and the second rated capacity; According to the third quantity and the replacement duration, the target delivery time of each newly-added replaced static reactive power compensation device is calculated and the delivery operation is performed.

2. The method according to claim 1, characterized in that The step of calculating the third number of newly added and replaced static VAR compensation devices comprises: determining whether the initial reactive load is greater than the first rated capacity; In a case where the initial reactive load is greater than the first rated capacity, determining the first rated capacity as the total dynamic reduction amount; In a case where the initial reactive load is not greater than the first rated capacity, determining the initial reactive load as the dynamic total amount to be reduced; The third quantity is calculated according to the dynamic total amount to be reduced, the first quantity, the second quantity and the second rated capacity.

3. The method according to claim 2, characterized in that Calculating the third quantity according to the dynamic total amount to be reduced, the first quantity, the second quantity and the second rated capacity includes: Obtaining the central voltage of the voltage central point in the target area, the voltage influence coefficient when replacing the static reactive power compensation device, and the balanced voltage and balanced reactive power of the power grid system; Calculate the static total amount to be invested according to the second quantity and the second rated capacity; The third quantity is calculated based on the total dynamic amount to be reduced, the first quantity, the second quantity, the second rated capacity, the total static amount to be invested, the central voltage, the voltage influence coefficient, the balanced voltage and the balanced reactive power.

4. The method according to claim 3, characterized in that Calculating the third quantity according to the dynamic total amount to be reduced, the first quantity, the second quantity, the second rated capacity, the static total amount to be invested, the central voltage, the voltage influence coefficient, the balanced voltage and the balanced reactive power includes: When the total amount of dynamic reactive power to be invested is greater than the total amount of static reactive power to be invested, the difference between the first amount and the second amount is determined as the third amount; When the total amount of dynamic reactive power to be invested is not greater than the total amount of static reactive power to be invested, the quotient of the total amount of dynamic reactive power to be reduced and the second rated capacity is determined as the third amount; Among them, the total static waiting amount, central voltage, voltage influence coefficient, balanced voltage and balanced reactive power meet the requirements of the preset first calculation formula.

5. The method according to claim 4, characterized in that The first calculation formula includes: Q e =(N-n c )Q C |Q e -Q AC |≤Q ref U+(N-n C )wQ C ≤U ref Among them, Qe represents the static total amount to be invested, N represents the first amount, and n c represents the second quantity, Q C Indicates the second rated capacity, Q ref represents balanced reactive power, U represents the central voltage, w represents the cigarette lighting influence coefficient, U ref Indicates the equilibrium voltage.

6. The method according to claim 1, characterized in that The replacement duration of each newly replaced static reactive compensation device is calculated based on the obtained deployment duration and margin duration of each of the reactive compensation devices.

7. The method according to claim 1, characterized in that Calculating the target delivery time of each newly delivered and replaced static reactive power compensation device according to the third quantity and the replacement duration includes: According to the third quantity, the replacement time and a preset second calculation formula, a target delivery time of each newly replaced static reactive power compensation device is calculated, wherein the second calculation formula includes: Among them, t si represents the time of placing the i-th newly replaced static reactive power compensation device, M represents the third number, i represents the sequence value of the newly replaced static reactive power compensation device placed, t pin Indicates the replacement duration.

8. The method according to any one of claims 1 to 7, characterized in that: Also includes: Calculate the total replacement duration of all newly replaced static VAR compensation devices according to the third number and the replacement duration; Calculating a decreasing rate of reactive output of the grid-connected converter according to the total replacement time and the initial reactive load; A simulation display is performed based on the total replacement time and the decrease rate.

9. A coordinated operation device of a grid-connected converter and a static VAR compensation device, characterized in that: include: An acquisition module is configured to acquire a first rated capacity of a grid-connected converter in a target area, an initial reactive load output at a current time, a first number of all static reactive compensation devices in the target area, a second number of static reactive compensation devices that have participated in the replacement, and a second rated capacity of each of the static reactive compensation devices, wherein the rated capacity of each of the static reactive compensation devices is the same; A first calculation module is configured to calculate a third number of newly replaced static reactive compensation devices and a replacement time length of each newly replaced static reactive compensation device according to the first rated capacity, the initial reactive load, the first number, the second number and the second rated capacity; The second calculation module is configured to calculate the target delivery time of each newly replaced static reactive power compensation device according to the third number and the replacement duration and perform the delivery operation.

10. A computing 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 method for coordinated operation of a grid-connected converter and a static VAR compensation device as described in any one of claims 1 to 7 are implemented.

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