A flexible direct current reactive power control method and device

Abstract

The embodiment of the application discloses a flexible direct current reactive power control method and device, the method comprises the following steps: according to the voltage drop deviation amount △U of the commutation bus of the flexible direct current receiving end commutation station when the short circuit fault of the alternating current system occurs and the voltage drop value △U of the alternating current system after the reactive power disturbance occurs i , and the voltage drop value △U of other direct current commutation buses after the reactive power disturbance of the alternating current system occurs j , and according to the voltage drop value △U of the direct current receiving end commutation bus i and △U j , the flexible direct current multi-inlet short circuit ratio K is calculated SCRi , the reactive power adjustment coefficient is calculated and determined according to the deviation amount △U and the K SCRi , and the reactive power compensation value of the flexible direct current receiving end commutation station is determined according to the reactive power adjustment coefficient and the deviation amount △U. The method and the system make full use of the direct current commutation converter margin to provide the reactive power compensation for the alternating current system, accelerate the recovery speed of the voltage of the fault near area, meanwhile, the control mode does not need the target value provided by the AVC, and is simple and easy to implement in engineering implementation.

Description

Technical Field

[0001] This invention relates to the field of ultra-high voltage power transmission technology, and in particular to a flexible DC reactive power control method and device. Background Technology

[0002] In the simulation analysis and operation control of flexible DC, the stability of voltage is highly dependent on the reactive power control mode of the flexible DC converter.

[0003] The existing reactive power control modes of flexible DC converters can be mainly divided into three types based on the equipment characteristics of the flexible DC converter: V / f (constant AC voltage, frequency) reactive power control, constant initial voltage operating point control, and constant reactive power control. V / f reactive power control refers to the control of AC system voltage amplitude, phase, and frequency by the flexible DC converter station. This control mode is only suitable for large-scale isolated new energy transmission and not for flexible DC systems connected to large-scale AC systems. Constant initial voltage operating point control refers to using the reactive power support of the flexible DC converter station to maintain a constant converter station bus amplitude. Under this control mode, due to the current carrying capacity limitation of the flexible DC converter devices, it may not be able to provide sufficient dynamic reactive power compensation and voltage support to the system during system faults. During system fault ride-through, the converter station bus voltage value cannot reach the target value of constant voltage control, and it is also not conducive to the equipment's own tolerance. Constant reactive power control means that the reactive power support of the flexible DC converter station is 0, and no reactive power is provided to the AC system. Currently, all operational flexible DC projects adopt this control strategy. The project implementation is simple and easy, and there is rich engineering experience. However, under this control mode, the near-field voltage recovery speed after a fault is slow, which threatens the voltage safety and stability of the system. Summary of the Invention

[0004] To address the technical problem in existing technologies where constant reactive power control fails to provide reactive power to the AC system, resulting in slow near-field voltage recovery after a fault and threatening the safety and stability of the system voltage, this invention provides a flexible DC reactive power control method and device.

[0005] According to one aspect of the present invention, a flexible DC reactive power control method is provided, the method comprising:

[0006] Collect the voltage value U1 of the converter bus of the i-th flexible DC receiving-end converter station before the AC system short-circuit fault and the voltage value U2 after the fault, and calculate the deviation of the AC system voltage drop ΔU, where 1≤i≤n;

[0007] The voltage drop ΔU of the converter bus of the i-th flexible DC receiving-end converter station after a reactive power disturbance in the AC system is collected. i And the voltage drop ΔU of the converter bus of other DC receiving-end converter stations after reactive power disturbance in the AC system. j Where 1≤j≤n and j≠i;

[0008] According to the voltage drop value ΔU i and △U j Calculate the flexible DC multi-infeed short-circuit ratio K of the i-th receiving-end flexible DC converter station. SCRi ;

[0009] Based on the deviation ΔU and the DC multi-feed short-circuit ratio K SCRi Calculate and determine the reactive power adjustment coefficient;

[0010] The reactive power compensation value of the i-th flexible DC receiving-end converter station is determined based on the reactive power adjustment coefficient and the deviation ΔU.

[0011] Optionally, in the above-described method embodiments of the present invention, the deviation ΔU of the AC system voltage drop is calculated using the following formula:

[0012] △U=U1-U2.

[0013] Optionally, in the above-described method embodiments of the present invention, based on the voltage drop value ΔU i and △U j Calculate the multi-infeed short-circuit ratio K of the i-th flexible DC receiving-end converter station. SCRi The calculation formula is as follows:

[0014]

[0015] In the formula, S' i Let P' be the rated capacity of the i-th flexible DC receiving-end converter station. i Let P' be the active power of the i-th flexible DC receiving-end converter station. j Let be the active power of the j-th DC receiving-end converter station.

[0016] Optionally, in the above-described method embodiments of the present invention, the deviation amount ΔU and the DC multi-infeed short-circuit ratio K are used as the basis for the calculation. SCRi The calculation and determination of the reactive power adjustment factor includes:

[0017] When a1≤K SCRi When ≤a2 and 0≤△U≤b1, the formula for calculating the reactive power adjustment coefficient K1 is:

[0018]

[0019] When a1≤K SCRi When ≤a2, b1<△U<1p.u., the formula for calculating the reactive power adjustment coefficient K1 is:

[0020] K1 = N*(S1 - P1)

[0021] When K SCRiWhen <a1, 0≤△U≤b2, the formula for calculating the reactive power adjustment coefficient K2 is:

[0022]

[0023] When K SCRi When <a1, b2 < ΔU < 1p.u., the formula for calculating the reactive power adjustment coefficient K2 is:

[0024] K2 = N*(S1 - P1);

[0025] When K SCR When >a2, 0≤△U≤1p.u., the formula for calculating the reactive power adjustment coefficient K3 is:

[0026]

[0027] In the formula, 0≤b2<b1≤1, pu is the per-unit voltage value, N is the number of individual flexible DC converters in the flexible DC converter station, S1 is the rated capacity of a single flexible DC converter, P1 is the active power of a single flexible DC converter, and U... min This is the lowest voltage after a general fault at the receiving end of the flexible DC converter station, and it is a settable constant value.

[0028] Optionally, in the above-described embodiments of the present invention, the reactive power compensation value of the i-th flexible DC receiving-end converter station is determined based on the reactive power adjustment coefficient and the deviation ΔU, and the calculation formula is as follows:

[0029] Q i =K*△U

[0030] In the formula, Q i is the reactive power compensation value of the i-th flexible DC receiving-end converter station, and K is the reactive power compensation coefficient.

[0031] According to another aspect of the present invention, a flexible DC reactive power control device is provided, the device comprising:

[0032] The first acquisition module is used to acquire the voltage value U1 of the converter bus of the i-th flexible DC receiving-end converter station before the AC system short-circuit fault and the voltage value U2 after the fault, and to calculate the deviation of the AC system voltage drop ΔU, where 1≤i≤n;

[0033] The second acquisition module is used to acquire the voltage drop ΔU of the converter bus of the i-th flexible DC receiving-end converter station after a reactive power disturbance occurs in the AC system. i And the voltage drop ΔU of the converter bus of other DC converter stations after reactive power disturbance in the AC system. j Where 1≤j≤n and j≠i;

[0034] The first calculation module is used to calculate based on the voltage drop value ΔU. i and △U j Calculate the multi-infeed short-circuit ratio K of the i-th flexible DC receiving-end converter station. SCRi ;

[0035] The second calculation module is used to calculate the deviation amount ΔU and the DC multi-feed short-circuit ratio K. SCRi Calculate and determine the reactive power adjustment coefficient;

[0036] The result output module is used to determine the reactive power compensation value of the i-th flexible DC receiving-end converter station based on the reactive power adjustment coefficient and the deviation ΔU.

[0037] Optionally, in the above-described embodiments of the apparatus of the present invention, the first acquisition module calculates the deviation ΔU of the AC system voltage drop, and the calculation formula is as follows:

[0038] △U=U1-U2.

[0039] Optionally, in the above-described device embodiments of the present invention, the first calculation module calculates the voltage drop value ΔU based on the voltage drop value. i and △U j Calculate the multi-infeed short-circuit ratio K of the i-th flexible DC receiving-end converter station. SCRi The calculation formula is as follows:

[0040]

[0041] In the formula, S' i Let P' be the rated capacity of the i-th flexible DC receiving-end converter station. i Let P' be the active power of the i-th flexible DC receiving-end converter station. j Let be the active power of the j-th DC converter station.

[0042] Optionally, in the above-described device embodiments of the present invention, the second calculation module calculates the deviation amount ΔU and the DC multi-infeed short-circuit ratio K. SCRi The calculation and determination of the reactive power adjustment factor includes:

[0043] When a1≤K SCRi When ≤a2 and 0≤△U≤b1, the formula for calculating the reactive power adjustment coefficient K1 is:

[0044]

[0045] When a1≤K SCRi When ≤a2, b1<△U<1p.u., the formula for calculating the reactive power adjustment coefficient K1 is:

[0046] K1 = N*(S1 - P1)

[0047] When KSCRi When <a1, 0≤△U≤b2, the formula for calculating the reactive power adjustment coefficient K2 is:

[0048]

[0049] When K SCRi When <a1, b2 < ΔU < 1p.u., the formula for calculating the reactive power adjustment coefficient K2 is:

[0050] K2 = N*(S1 - P1);

[0051] When K SCR When >a2, 0≤△U≤1p.u., the formula for calculating the reactive power adjustment coefficient K3 is:

[0052]

[0053] In the formula, 0≤b2<b1≤1, pu is the per-unit voltage value, N is the number of individual flexible DC converters in the flexible DC converter station, S1 is the rated capacity of a single flexible DC converter, P1 is the active power of a single flexible DC converter, and U... min This is the lowest voltage after a general fault at the receiving end of the flexible DC converter station, and it is a settable constant value.

[0054] Optionally, in the above-described embodiments of the apparatus of the present invention, the result output module determines the reactive power compensation value of the i-th flexible DC receiving-end converter station based on the reactive power adjustment coefficient and the deviation ΔU, and the calculation formula is as follows:

[0055] Q i =K*△U

[0056] In the formula, Q i is the reactive power compensation value of the i-th flexible DC receiving-end converter station, and K is the reactive power compensation coefficient.

[0057] The flexible DC reactive power control method and apparatus provided in this embodiment include: the method comprising: based on the voltage drop deviation ΔU of the converter bus of the flexible DC receiving-end converter station during an AC system short-circuit fault, and the voltage drop value ΔU after a reactive power disturbance occurs in the AC system. i And the voltage drop ΔU of the converter bus of other DC receiving-end converter stations after reactive power disturbance in the AC system. j And based on the voltage drop ΔU at the DC receiving end of the converter bus. i and △U j Calculate the short-circuit ratio K of flexible DC multi-infeed SCRi According to the deviation amount ΔU and the DC multi-feed short-circuit ratio K SCRiThe reactive power adjustment coefficient is calculated and determined; based on the reactive power adjustment coefficient and the deviation ΔU, the reactive power compensation value of the flexible DC receiving-end converter station is determined. The method and system determine the reactive power adjustment coefficient by comparing the voltage changes of the flexible DC converter station before and after a short-circuit fault, and before and after a reactive power disturbance in the AC system. This ensures that while the flexible DC converter station experiences fault ride-through, it fully utilizes the converter margin to provide reactive power compensation to the AC system, accelerating the recovery speed of the voltage in the fault's vicinity and maintaining the safe and stable voltage of the system. Furthermore, this control mode can automatically determine the reactive power compensation capacity without requiring a target value from the AVC, making it simple and easy to implement in engineering projects.

[0058] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0059] The above and other objects, features, and advantages of the present invention will become more apparent from the more detailed description of the embodiments of the invention in conjunction with the accompanying drawings. The drawings are provided to further illustrate the embodiments of the invention and form part of the specification. They are used together with the embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings, the same reference numerals generally represent the same parts or steps.

[0060] Figure 1 This is a flowchart illustrating a flexible DC reactive power control method provided in an exemplary embodiment of the present invention.

[0061] Figure 2 This is a schematic diagram of the structure of a flexible DC reactive power control device provided in an exemplary embodiment of the present invention. Detailed Implementation

[0062] Hereinafter, exemplary embodiments according to the present invention will be described in detail with reference to the accompanying drawings. Obviously, the described embodiments are merely some embodiments of the present invention, and not all embodiments of the present invention. It should be understood that the present invention is not limited to the exemplary embodiments described herein.

[0063] It should be noted that, unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps described in these embodiments do not limit the scope of the invention.

[0064] Those skilled in the art will understand that the terms "first," "second," etc., in the embodiments of the present invention are only used to distinguish different steps, devices, or modules, and do not represent any specific technical meaning, nor do they indicate a necessary logical order between them.

[0065] It should also be understood that in the embodiments of the present invention, "multiple" can refer to two or more, and "at least one" can refer to one, two or more.

[0066] It should also be understood that any component, data or structure mentioned in the embodiments of the present invention can generally be understood as one or more unless explicitly defined or given contrary instructions in the context.

[0067] Furthermore, the term "and / or" in this invention is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, the character " / " in this invention generally indicates that the preceding and following related objects have an "or" relationship.

[0068] It should also be understood that the description of the various embodiments in this invention emphasizes the differences between the various embodiments, and the similarities or similarities can be referred to each other. For the sake of brevity, they will not be described in detail.

[0069] At the same time, it should be understood that, for ease of description, the dimensions of the various parts shown in the accompanying drawings are not drawn according to actual scale.

[0070] The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the invention or its application or use.

[0071] Techniques, methods, and equipment known to those skilled in the art may not be discussed in detail, but where appropriate, they should be considered part of the specification.

[0072] It should be noted that similar labels and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be discussed further in subsequent figures.

[0073] The embodiments of this invention can be applied to electronic devices such as terminal devices, computer systems, and servers, and can operate together with a wide range of other general-purpose or special-purpose computing system environments or configurations. Well-known examples of terminal devices, computing systems, environments, and / or configurations suitable for use with electronic devices such as terminal devices, computer systems, and servers include, but are not limited to: personal computer systems, server computer systems, thin clients, thick clients, handheld or laptop devices, microprocessor-based systems, set-top boxes, programmable consumer electronics, network PCs, minicomputer systems, mainframe computer systems, and distributed cloud computing environments including any of the above systems, etc.

[0074] Electronic devices such as terminal devices, computer systems, and servers can be described in the general context of computer system executable instructions (such as program modules) executed by a computer system. Typically, program modules can include routines, programs, object programs, components, logic, data structures, etc., which perform specific tasks or implement specific abstract data types. Computer systems / servers can be implemented in distributed cloud computing environments, where tasks are executed by remote processing devices linked through communication networks. In distributed cloud computing environments, program modules can reside on local or remote computing system storage media, including storage devices.

[0075] Exemplary methods

[0076] Figure 1 This is a schematic flowchart of a flexible DC reactive power control method provided by an exemplary embodiment of the present invention. This embodiment can be stored in a storage medium and applied to electronic devices, such as… Figure 1 As shown, the method described in the embodiment includes the following steps:

[0077] Step 101: Collect the voltage value U1 of the converter bus of the i-th flexible DC receiving-end converter station before the AC system short-circuit fault and the voltage value U2 after the fault, and calculate the deviation of the AC system voltage drop ΔU, where 1≤i≤n.

[0078] Preferably, the deviation ΔU of the AC system voltage drop is calculated using the following formula:

[0079] △U=U1-U2.

[0080] Step 102: Collect the voltage drop ΔU of the converter bus of the i-th flexible DC receiving-end converter station after a reactive power disturbance occurs in the AC system. i And the voltage drop ΔU of the converter bus of other DC receiving-end converter stations after reactive power disturbance in the AC system. j , where 1≤j≤n and j≠i.

[0081] Step 103, based on the voltage drop value ΔU i and △U j Calculate the flexible DC multi-infeed short-circuit ratio K of the i-th receiving-end flexible DC converter station. SCRi .

[0082] Preferably, based on the voltage drop value ΔU i and △U j Calculate the multi-infeed short-circuit ratio K of the i-th flexible DC receiving-end converter station. SCRi The calculation formula is as follows:

[0083]

[0084] In the formula, S' i Let P' be the rated capacity of the i-th flexible DC receiving-end converter station. i Let P' be the active power of the i-th flexible DC receiving-end converter station. j Let be the active power of the j-th DC receiving-end converter station.

[0085] Step 104, based on the deviation amount ΔU and the DC multi-infeed short-circuit ratio K SCRi Calculate and determine the reactive power adjustment coefficient.

[0086] Preferably, based on the deviation amount ΔU and the DC multi-feed short-circuit ratio K SCRi The calculation and determination of the reactive power adjustment factor includes:

[0087] When a1≤K SCRi When ≤a2 and 0≤△U≤b1, the formula for calculating the reactive power adjustment coefficient K1 is:

[0088]

[0089] When a1≤K SCRi When ≤a2, b1<△U<1p.u., the formula for calculating the reactive power adjustment coefficient K1 is:

[0090] K1 = N*(S1 - P1)

[0091] When K SCRi When <a1, 0≤△U≤b2, the formula for calculating the reactive power adjustment coefficient K2 is:

[0092]

[0093] When K SCRi When <a1, b2 < ΔU < 1p.u., the formula for calculating the reactive power adjustment coefficient K2 is:

[0094] K2 = N*(S1 - P1);

[0095] When K SCR When >a2, 0≤△U≤1p.u., the formula for calculating the reactive power adjustment coefficient K3 is:

[0096]

[0097] In the formula, 0≤b2<b1≤1, pu is the per-unit voltage value, N is the number of individual flexible DC converters in the flexible DC converter station, S1 is the rated capacity of a single flexible DC converter, P1 is the active power of a single flexible DC converter, and U... min This is the lowest voltage after a general fault at the receiving end of the flexible DC converter station, and it is a settable constant value.

[0098] In one embodiment, Umin Generally, 0.2 PU is used, a1 is 2, a2 ​​is 3, b2 is 0.4 PU, and b1 is 0.8 PU.

[0099] Step 105: Determine the reactive power compensation value of the i-th flexible DC receiving-end converter station based on the reactive power adjustment coefficient and the deviation ΔU.

[0100] Preferably, the reactive power compensation value of the i-th receiving-end flexible DC converter station is determined based on the reactive power adjustment coefficient and the deviation ΔU, and the calculation formula is as follows:

[0101] Q i =K*△U

[0102] In the formula, Q i is the reactive power compensation value of the i-th flexible DC receiving-end converter station, and K is the reactive power compensation coefficient.

[0103] The flexible DC reactive power control method described in this embodiment is based on the flexible DC multi-infeed short-circuit ratio K. SCRi Different reactive power adjustment coefficient values ​​are determined based on the magnitude of the load and the intensity of the AC / DC system fed into the receiving end. This allows the flexible DC receiving end converter station to fully utilize the margin of the flexible DC converter (the difference between the capacity of the flexible DC converter and the active power) to provide reactive power compensation for the system while ensuring fault ride-through. The voltage recovery speed in the fault near-zone is faster, and the reactive power control mode of the flexible DC is more reasonable.

[0104] Taking the Baihetan-Jiangsu flexible DC transmission line as an example, the reactive power control method for flexible DC transmission described in this embodiment is implemented as follows:

[0105] Step 1: Measure the voltage values ​​of the flexible DC receiving-end converter station before and after the AC system short-circuit fault, and record them as U1 = 0.98pu and U2 = 0.8pu respectively. Based on the voltage values ​​before and after the fault, calculate the voltage drop deviation ΔU = U1 - U2 = 0.18pu.

[0106] Step 2: Measure the voltage drop ΔU on the bus of this DC converter station caused by the reactive power disturbance of the system. i The voltage drop ΔU of the bus at other DC converter stations j The short-circuit ratio K of the flexible DC multi-infeed system is calculated according to the formula. SCR =2.8.

[0107] Step 3: When the flexible DC multi-feed short-circuit ratio is 2 <K SCR When the value is less than 3, the DC-fed AC / DC system at the receiving end is a weak system. When 0 ≤ ΔU ≤ 0.8pu, since N is the number of individual flexible DC converters in the flexible DC converter station, which is 2, S1 is the rated capacity of a single flexible DC converter, which is 1000MW, and P1 is the active power of a single flexible DC converter, which is 667MW, Umin Assuming the minimum voltage of the flexible DC converter station is 0.2 pu, then according to the formula... K1 = 833.

[0108] Step 4: Based on the calculated reactive power adjustment coefficient and voltage deviation, the reactive power compensation value Q of the flexible DC receiving-end converter station can be determined. i =K*△U=150Mvar.

[0109] After the flexible DC receiving-end converter station performs reactive power control on the AC system according to the calculated reactive power compensation value, the voltage in the fault-prone area of ​​the AC system recovers quickly, effectively proving the rationality of the flexible DC reactive power control method described in this embodiment.

[0110] Exemplary device

[0111] Figure 2 This is a schematic diagram of the structure of a flexible DC reactive power control device provided in an exemplary embodiment of the present invention. Figure 2 As shown, the device includes:

[0112] The first acquisition module 201 is used to acquire the voltage value U1 of the converter bus of the i-th flexible DC receiving-end converter station before the AC system short-circuit fault and the voltage value U2 after the fault, and to calculate the deviation of the AC system voltage drop ΔU, where 1≤i≤n;

[0113] The second acquisition module 202 is used to acquire the voltage drop ΔU of the converter bus of the i-th flexible DC receiving-end converter station after a reactive power disturbance occurs in the AC system. i And the voltage drop ΔU of the converter bus of other DC converter stations after reactive power disturbance in the AC system. j Where 1≤j≤n and j≠i;

[0114] The first calculation module 203 is used to calculate based on the voltage drop value ΔU. i and △U j Calculate the multi-infeed short-circuit ratio K of the i-th flexible DC receiving-end converter station. SCRi ;

[0115] The second calculation module 204 is used to calculate the deviation amount ΔU and the DC multi-infeed short-circuit ratio K based on the deviation amount ΔU and the DC multi-infeed short-circuit ratio K. SCRi Calculate and determine the reactive power adjustment coefficient;

[0116] The result output module 205 is used to determine the reactive power compensation value of the i-th flexible DC receiving-end converter station based on the reactive power adjustment coefficient and the deviation ΔU.

[0117] Preferably, the first acquisition module 201 calculates the deviation ΔU of the AC system voltage drop, and the calculation formula is as follows:

[0118] △U=U1-U2.

[0119] Preferably, the first calculation module 203 calculates the voltage drop value ΔU based on the voltage drop value. i and △U j Calculate the multi-infeed short-circuit ratio K of the i-th flexible DC receiving-end converter station. SCRi The calculation formula is as follows:

[0120]

[0121] In the formula, S' i Let P' be the rated capacity of the i-th flexible DC receiving-end converter station. i Let P' be the active power of the i-th flexible DC receiving-end converter station. j Let be the active power of the j-th DC converter station.

[0122] Preferably, the second calculation module 204 calculates the deviation amount ΔU and the DC multi-feed short-circuit ratio K. SCRi The calculation and determination of the reactive power adjustment factor includes:

[0123] When a1≤K SCRi When ≤a2 and 0≤△U≤b1, the formula for calculating the reactive power adjustment coefficient K1 is:

[0124]

[0125] When a1≤K SCRi When ≤a2, b1<△U<1p.u., the formula for calculating the reactive power adjustment coefficient K1 is:

[0126] K1 = N*(S1 - P1)

[0127] When K SCRi When <a1, 0≤△U≤b2, the formula for calculating the reactive power adjustment coefficient K2 is:

[0128]

[0129] When K SCRi When <a1, b2 < ΔU < 1p.u., the formula for calculating the reactive power adjustment coefficient K2 is:

[0130] K2 = N*(S1 - P1);

[0131] When K SCR When >a2, 0≤△U≤1p.u., the formula for calculating the reactive power adjustment coefficient K3 is:

[0132]

[0133] In the formula, 0≤b2<b1≤1, pu is the per-unit voltage value, N is the number of individual flexible DC converters in the flexible DC converter station, S1 is the rated capacity of a single flexible DC converter, P1 is the active power of a single flexible DC converter, and U... min This is the lowest voltage after a general fault at the receiving end of the flexible DC converter station, and it is a settable constant value.

[0134] Preferably, the result output module 205 determines the reactive power compensation value of the i-th flexible DC receiving-end converter station based on the reactive power adjustment coefficient and the deviation ΔU, and the calculation formula is as follows:

[0135] Q i =K*△U

[0136] In the formula, Q i is the reactive power compensation value of the i-th flexible DC receiving-end converter station, and K is the reactive power compensation coefficient.

[0137] The steps of the flexible DC reactive power control device described in this embodiment, which controls the reactive power of the AC system after a short-circuit fault, are the same as those of the flexible DC reactive power control method described in this invention, and the technical effects achieved are also the same. Therefore, they will not be repeated here.

[0138] In addition to the methods and systems described above, embodiments of this disclosure may also be computer program products comprising computer program instructions that, when executed by a processor, cause the processor to perform the steps of the methods for wireless partial discharge sensors according to various embodiments of this disclosure as described in the "Exemplary Methods" section of this specification.

[0139] The computer program product can be written in any combination of one or more programming languages ​​to perform the operations of the embodiments of this disclosure. The programming languages ​​include object-oriented programming languages ​​such as Java and C++, as well as conventional procedural programming languages ​​such as C or similar languages. The program code can be executed entirely on a user's computing device, partially on a user's computing device, as a standalone software package, partially on a user's computing device and partially on a remote computing device, or entirely on a remote computing device or server.

[0140] Furthermore, embodiments of this disclosure may also be computer-readable storage media having computer program instructions stored thereon, which, when executed by a processor, cause the processor to perform the steps of the methods for wireless partial discharge sensors according to various embodiments of this disclosure as described in the "Exemplary Methods" section above.

[0141] The computer-readable storage medium may be any combination of one or more readable media. A readable medium may be a readable signal medium or a readable storage medium. A readable storage medium may, for example, include, but is not limited to, electrical, magnetic, optical, electromagnetic, infrared, or semiconductor systems, apparatuses, or devices, or any combination thereof. More specific examples of readable storage media (a non-exhaustive list) include: electrical connections having one or more wires, portable disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fibers, portable compact disk read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination thereof.

[0142] The basic principles of this disclosure have been described above with reference to specific embodiments. However, it should be noted that the advantages, benefits, and effects mentioned in this disclosure are merely examples and not limitations, and should not be considered as essential features of each embodiment of this disclosure. Furthermore, the specific details disclosed above are for illustrative and facilitative purposes only, and are not limitations. These details do not limit the scope of this disclosure to the necessity of employing the aforementioned specific details for implementation.

[0143] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For system embodiments, since they largely correspond to method embodiments, the description is relatively simple; relevant parts can be referred to the descriptions in the method embodiments.

[0144] The block diagrams of devices, apparatuses, devices, and systems disclosed herein are merely illustrative examples and are not intended to require or imply that they must be connected, arranged, or configured in the manner shown in the block diagrams. As those skilled in the art will recognize, these devices, apparatuses, devices, and systems can be connected, arranged, and configured in any manner. Words such as “comprising,” “including,” “having,” etc., are open-ended terms meaning “including but not limited to,” and are used interchangeably with them. The terms “or” and “and” as used herein refer to the terms “and / or,” and are used interchangeably with them unless the context clearly indicates otherwise. The term “such as” as used herein refers to the phrase “such as but not limited to,” and is used interchangeably with it.

[0145] The methods and apparatus of this disclosure may be implemented in many ways. For example, they may be implemented by software, hardware, firmware, or any combination of software, hardware, and firmware. The above-described order of steps for the methods is for illustrative purposes only, and the steps of the methods of this disclosure are not limited to the order specifically described above unless otherwise specifically stated. Furthermore, in some embodiments, this disclosure may also be implemented as a program recorded on a recording medium, the program including machine-readable instructions for implementing the methods according to this disclosure. Thus, this disclosure also covers recording media storing programs for performing the methods according to this disclosure.

[0146] It should also be noted that in the apparatus, devices, and methods of this disclosure, the components or steps are decomposable and / or recombinable. Such decomposition and / or recombination should be considered equivalent to the present disclosure. The above description of the disclosed aspects is provided to enable any person skilled in the art to make or use this disclosure. Various modifications to these aspects will be readily apparent to those skilled in the art, and the general principles defined herein can be applied to other aspects without departing from the scope of this disclosure. Therefore, this disclosure is not intended to be limited to the aspects shown herein, but rather to be carried out within the widest scope consistent with the principles and novel features disclosed herein.

[0147] The above description has been given for purposes of illustration and description. Furthermore, this description is not intended to limit the embodiments of this disclosure to the forms disclosed herein. Although numerous exemplary aspects and embodiments have been discussed above, those skilled in the art will recognize certain variations, modifications, alterations, additions, and sub-combinations therein.

Claims

1. A flexible DC reactive power control method, characterized in that, The method includes: Collect the voltage value U1 of the converter bus of the i-th flexible DC receiving-end converter station before the AC system short-circuit fault and the voltage value U2 after the fault, and calculate the deviation of the AC system voltage drop ΔU, where 1≤i≤n; The voltage drop ΔU of the converter bus of the i-th flexible DC receiving-end converter station after a reactive power disturbance in the AC system is collected. i And the voltage drop ΔU of the converter bus of other DC receiving-end converter stations after reactive power disturbance in the AC system. j Where 1≤j≤n and j≠i; According to the voltage drop value ΔU i and △U j Calculate the flexible DC multi-infeed short-circuit ratio K of the i-th receiving-end flexible DC converter station. SCRi ; Based on the deviation ΔU and the flexible DC multi-infeed short-circuit ratio K SCRi The calculation and determination of the reactive power adjustment factor includes: When a1≤K SCRi When ≤a2, 0≤△U≤b1, the reactive power adjustment coefficient K 11 The calculation formula is: When a1≤K SCRi When ≤a2, b1<△U<1p.u., the reactive power adjustment coefficient K 12 The calculation formula is: When K SCRi When <a1, 0≤△U≤b2, the reactive power adjustment coefficient K 21 The calculation formula is: When K SCRi When <a1, b2 < ΔU < 1p.u., the reactive power adjustment coefficient K 22 The calculation formula is: When K SCR When >a2, 0≤△U≤1p.u., the formula for calculating the reactive power adjustment coefficient K3 is: In the formula, 0≤b2<b1≤1, pu is the per-unit voltage value, N is the number of individual flexible DC converters in the flexible DC converter station, S1 is the rated capacity of a single flexible DC converter, P1 is the active power of a single flexible DC converter, and U... min It is a settable constant value; The reactive power compensation value of the i-th flexible DC receiving-end converter station is determined based on the reactive power adjustment coefficient and the deviation ΔU.

2. The method according to claim 1, characterized in that, The formula for calculating the voltage drop deviation ΔU in an AC system is as follows: △U = U1 - U2.

3. The method according to claim 1, characterized in that, According to the voltage drop value ΔU i and △U j Calculate the flexible DC multi-infeed short-circuit ratio K of the i-th flexible DC receiving-end converter station. SCRi The calculation formula is as follows: In the formula, Let i be the rated capacity of the i-th flexible DC receiving-end converter station. Let be the active power of the i-th flexible DC receiving-end converter station. Let be the active power of the j-th DC receiving-end converter station.

4. The method according to claim 1, characterized in that, The reactive power compensation value of the i-th receiving-end flexible DC converter station is determined based on the reactive power adjustment coefficient and the deviation ΔU, and the calculation formula is as follows: Q i =K*△U In the formula, Q i is the reactive power compensation value of the i-th flexible DC receiving-end converter station, and K is the reactive power compensation coefficient.

5. A flexible DC reactive power control device, characterized in that, The device includes: The first acquisition module is used to acquire the voltage value U1 of the converter bus of the i-th flexible DC receiving-end converter station before the AC system short-circuit fault and the voltage value U2 after the fault, and to calculate the deviation of the AC system voltage drop ΔU, where 1≤i≤n; The second acquisition module is used to acquire the voltage drop ΔU of the converter bus of the i-th flexible DC receiving-end converter station after a reactive power disturbance occurs in the AC system. i And the voltage drop ΔU of the converter bus of other DC converter stations after reactive power disturbance in the AC system. j Where 1≤j≤n and j≠i; The first calculation module is used to calculate based on the voltage drop value ΔU. i and △U j Calculate the flexible DC multi-infeed short-circuit ratio K of the i-th flexible DC receiving-end converter station. SCRi ; The second calculation module is used to calculate the deviation ΔU and the flexible DC multi-infeed short-circuit ratio K. SCRi The calculation and determination of the reactive power adjustment factor includes: When a1≤K SCRi When ≤a2, 0≤△U≤b1, the reactive power adjustment coefficient K 11 The calculation formula is: When a1≤K SCRi When ≤a2, b1<△U<1p.u., the reactive power adjustment coefficient K 12 The calculation formula is: When K SCRi When <a1, 0≤△U≤b2, the reactive power adjustment coefficient K 21 The calculation formula is: When K SCRi When <a1, b2 < ΔU < 1p.u., the reactive power adjustment coefficient K 22 The calculation formula is: When K SCR When >a2, 0≤△U≤1p.u., the formula for calculating the reactive power adjustment coefficient K3 is: In the formula, 0≤b2<b1≤1, pu is the per-unit voltage value, N is the number of individual flexible DC converters in the flexible DC converter station, S1 is the rated capacity of a single flexible DC converter, P1 is the active power of a single flexible DC converter, and U... min It is a settable constant value; The result output module is used to determine the reactive power compensation value of the i-th flexible DC receiving-end converter station based on the reactive power adjustment coefficient and the deviation ΔU.

6. The apparatus according to claim 5, characterized in that, The first acquisition module calculates the deviation ΔU of the AC system voltage drop, and the calculation formula is as follows: △U = U1 - U2.

7. The apparatus according to claim 5, characterized in that, The first calculation module calculates based on the voltage drop value ΔU. i and △U j Calculate the flexible DC multi-infeed short-circuit ratio K of the i-th flexible DC receiving-end converter station. SCRi The calculation formula is as follows: In the formula, Let i be the rated capacity of the i-th flexible DC receiving-end converter station. Let be the active power of the i-th flexible DC receiving-end converter station. Let be the active power of the j-th DC receiving-end converter station.

8. The apparatus according to claim 5, characterized in that, The result output module determines the reactive power compensation value of the i-th flexible DC receiving-end converter station based on the reactive power adjustment coefficient and the deviation ΔU. The calculation formula is as follows: Q i =K*△U In the formula, Q i is the reactive power compensation value of the i-th flexible DC receiving-end converter station, and K is the reactive power compensation coefficient.

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