Harmonic responsibility evaluation method and system based on multi-frequency decoupling

Abstract

The invention belongs to the field of harmonic wave processing, and provides a harmonic wave responsibility evaluation method and system based on multi-frequency decoupling. The evaluation method comprises the following steps: taking a node of harmonic traceability to be evaluated as a concerned node, and constructing a single harmonic source grid-connected equivalent model considering the harmonic coupling influence based on harmonic voltage data and harmonic current data of a harmonic frequency considered by the concerned node in a predetermined time period participating in evaluation; based on a single harmonic source grid-connected equivalent model, obtaining a decoupling relation between the h-order harmonic voltage at the user side common coupling point and the user same-frequency harmonic current, the other-frequency voltage and the background harmonic voltage, and obtaining an evaluation index according to the projection of each frequency harmonic voltage at the h-order harmonic voltage at the user side common coupling point; and respectively quantifying the contribution levels of the user-side same-frequency harmonic current source, the non-same-frequency harmonic voltage and the system-side same-frequency background harmonic voltage to the harmonic voltage at the concerned node to obtain a harmonic traceability quantitative evaluation result so as to identify the harmonic dominant frequency.

Description

Technical Field

[0001] The present invention belongs to the field of harmonic processing, and in particular relates to a harmonic responsibility assessment method and system based on multi-frequency decoupling. Background Art

[0002] The statements in this section merely provide background information related to the present invention and do not necessarily constitute prior art.

[0003] With the large-scale application of large-scale heterogeneous power electronic equipment in new power systems, the harmonic problem of power systems is becoming more and more serious, threatening the stability of the power grid and the safety of electricity use. However, the harmonic disturbances generated by power electronic equipment present a new characteristic of strong coupling, which will lead to significant and complex interactions between harmonic voltages and currents of different frequencies at the grid connection point. Under the interaction between power electronic equipment on the user side and background harmonics on the system side, harmonic voltages and currents of different frequencies are superimposed on each other, continuously aggravating the harmonic distortion problem of the system. Accurately identifying the root causes of harmonic disturbances and reasonably evaluating the specific impacts of power generation, power grids and users on power quality can ensure high-quality power supply in the power system.

[0004] The prior art believes that the user side does not contain the same frequency harmonic source, but only the coupling frequency harmonic source, which will cause the responsibility of the same frequency harmonics to come entirely from the background harmonics on the system side, while the responsibility of other coupling frequency harmonics comes entirely from the user side. In fact, it is common knowledge in the field that there must be a same frequency harmonic current source on the user side, which will cause harmonic distortion at the PCC under the interaction with the background harmonics on the system side. Therefore, when determining the harmonic source at the PCC, the impact of the same frequency harmonics on the user side cannot be ignored.

[0005] In addition, common sense holds that the harmonics generated on the user side are the main cause of harmonic distortion at the PCC, among which the same-frequency harmonics account for the main component, and the sum of non-same-frequency harmonics generally does not exceed the same-frequency harmonics. The existing technical model lacks the same-frequency harmonic source on the user side, which can be regarded as allocating the responsibility of the same-frequency harmonics generated on the user side to other non-same-frequency voltages. The evaluation results do not include the impact of the same-frequency harmonics on the user side, which is inconsistent with the actual principle of harmonic generation on the user side. In addition, the same-frequency harmonic current is obtained by analyzing the state at any two times in the same time period, while the non-same-frequency harmonic is obtained based on state fitting. There is a significant difference in the acquisition method, which is only a simple superposition on the basis of the original model, and the same-frequency harmonic current source cannot be obtained.

[0006] In summary, the current research on harmonic source tracing and quantitative evaluation equivalent the harmonic source to a harmonic Norton model. This model only includes a constant current source and the shunt harmonic impedance of the same frequency, and cannot effectively analyze the coupling effect between harmonic voltages and currents of different frequencies, making it difficult to distinguish the interactive influence between power electronic devices on the user side and background harmonics on the user side. The current harmonic source tracing and quantitative evaluation method based on the harmonic Norton model cannot deeply understand the essence of harmonic disturbances under multi-frequency coupling, so it is impossible to determine the true dominant frequency component of harmonic distortion, further increasing the difficulty of obtaining a reliable and accurate source tracing result. Summary of the Invention

[0007] To solve the technical problems existing in the above-mentioned background technology, the present invention provides a harmonic responsibility evaluation method and system based on multi-frequency decoupling. It uses a harmonic coupling model to characterize the user side in a single harmonic source scenario, establishes a multi-frequency responsibility evaluation model for a single harmonic source connected to the grid, can describe the dominant influence of the h-th harmonic voltage at the point of common coupling (PCC) between the system side and the user side, analyze the relationship between the user side's harmonic current of the same frequency, other non-homogeneous voltages, and the background harmonic voltage of the system side, and further determine the dominant disturbance frequency on the basis of traditional dominant source identification.

[0008] To achieve the above object, the present invention adopts the following technical solutions:

[0009] The first aspect of the present invention provides a harmonic responsibility evaluation method based on multi-frequency decoupling.

[0010] A harmonic responsibility evaluation method based on multi-frequency decoupling includes:

[0011] Taking the node to be evaluated for harmonic source tracing as the concerned node, based on the harmonic voltage data and harmonic current data of the considered harmonic frequencies at the concerned node during a pre-determined evaluation time period, establishing a user-side harmonic coupling model, and then constructing an equivalent model for a single harmonic source connected to the grid considering the influence of harmonic coupling;

[0012] Based on the equivalent model for a single harmonic source connected to the grid, obtaining the decoupling relationship between the h-th harmonic voltage at the user-side point of common coupling, the harmonic current of the same frequency of the user, the voltages of other frequencies, and the background harmonic voltage, and then obtaining an evaluation index according to the projection of the harmonic voltages of each frequency on the h-th harmonic voltage at the user-side point of common coupling;

[0013] According to the evaluation index, respectively quantifying the contribution levels of the user-side harmonic current source of the same frequency, the non-homogeneous harmonic voltages, and the system-side background harmonic voltage of the same frequency to the harmonic voltage at the concerned node, obtaining a quantitative evaluation result of harmonic source tracing to identify the dominant harmonic frequency.

[0014] As an implementation manner, the evaluation indexes include: the projection amount of the h - th harmonic voltage of the system - side co - frequency background harmonics at the common coupling point on the user side, the projection amount of the h - th harmonic voltage of the same frequency on the user side at the common coupling point on the user side, and the projection amount of the k - th harmonic voltage on the user side at the h - th harmonic voltage at the common coupling point on the user side.

[0015] As an implementation manner, the projection of the harmonic voltage of each frequency at the h - th harmonic voltage at the common coupling point on the user side is:

[0016]

[0017] Among them, is the h - th harmonic voltage at the common coupling point on the user side; H h,k is the projection amount of the k - th harmonic voltage on the user side at the h - th harmonic voltage at the common coupling point on the user side, and k≠h; H I,h is the projection amount of the h - th harmonic voltage of the same frequency on the user side at the common coupling point on the user side; H S,h is the projection amount of the system - side co - frequency background harmonics at the h - th harmonic voltage at the common coupling point on the user side; C h,k is the influence coefficient of the non - co - frequency k - th harmonic voltage, and k≠h; is the k - th harmonic voltage at the common coupling point on the user side; cos is the cosine function; C I,h is the influence coefficient of the user - side co - frequency harmonic current source; is the user - side h - th harmonic equivalent current source; C S,h is the influence coefficient of the background - side co - frequency background harmonic voltage; is the system - side h - th harmonic equivalent voltage source.

[0018] As an implementation manner, the decoupling relationship between the h - th harmonic voltage at the common coupling point on the user side and the user's same - frequency harmonic current, other - frequency voltages, and background harmonic voltages is:

[0019]

[0020] Among them, is the h - th harmonic voltage at the common coupling point on the user side; C h,k is the influence coefficient of the non - co - frequency k - th harmonic voltage, and k≠h; is the k - th harmonic voltage at the common coupling point on the user side; C I,h is the influence coefficient of the user - side co - frequency harmonic current source; is the user - side h - th harmonic equivalent current source; C S,h is the influence coefficient of the background - side co - frequency background harmonic voltage; is the system - side h - th harmonic equivalent voltage source; Y h,his the influence coefficient of the user-side in-phase harmonic current source on the h-th harmonic current; Y S,h is the influence coefficient of the background-side in-phase background harmonic voltage on the h-th harmonic current; H is the harmonic order.

[0021] As an implementation, if the projection of the system-side in-phase background harmonic voltage at the h-th harmonic voltage at the point of common coupling on the user side is greater than the projection of all frequencies on the user side at the h-th harmonic voltage at the point of common coupling on the user side, it is determined that the dominant source of the harmonic is the system side;

[0022] As an implementation, if the projection of the user-side harmonic current source at the h-th harmonic voltage at the point of common coupling on the user side is greater than the projection of other frequencies on the user side at the h-th harmonic voltage at the point of common coupling on the user side, and at the same time greater than the projection of the user-side background harmonic at the h-th harmonic voltage at the point of common coupling on the user side, it is determined that the dominant source of the harmonic is the user-side harmonic source.

[0023] As an implementation, if the projection of the user-side k-th harmonic voltage at the h-th harmonic voltage at the point of common coupling on the user side is greater than the projection of other frequencies at the h-th harmonic voltage at the point of common coupling on the user side, and at the same time greater than the projection of the user-side background harmonic at the h-th harmonic voltage at the point of common coupling on the user side, it is determined that the dominant source of the harmonic is the user side, and the dominant frequency is the k-th harmonic on the user side.

[0024] The second aspect of the present invention provides a harmonic responsibility assessment system based on multi-frequency decoupling.

[0025] A harmonic responsibility assessment system based on multi-frequency decoupling, which includes:

[0026] A single harmonic source grid-connected equivalent model construction module, which is used to take the node to be evaluated for harmonic tracing as the concerned node, and based on the harmonic voltage data and harmonic current data of the concerned node at the harmonic frequencies considered during the pre-determined evaluation period, establish a user-side harmonic coupling model, and then construct a single harmonic source grid-connected equivalent model considering the influence of harmonic coupling;

[0027] An evaluation index determination module, which is used to obtain the decoupling relationship between the h-th harmonic voltage at the point of common coupling on the user side and the user's in-phase harmonic current, other frequency voltages, and background harmonic voltages based on the single harmonic source grid-connected equivalent model, and then obtain the evaluation index according to the projection of the harmonic voltages at each frequency at the h-th harmonic voltage at the point of common coupling on the user side;

[0028] A quantitative evaluation result calculation module, which is used to respectively quantify the contribution levels of the user-side in-phase harmonic current source, non-in-phase frequency harmonic voltages, and the system-side in-phase background harmonic voltages to the harmonic voltage at the concerned node according to the evaluation index, and obtain the quantitative evaluation result of harmonic tracing to identify the dominant harmonic frequency.

[0029] The third aspect of the present invention provides a computer-readable storage medium.

[0030] A computer-readable storage medium, on which a computer program is stored, and when the program is executed by a processor, it implements the steps in the above-mentioned harmonic liability assessment method based on multi-frequency decoupling.

[0031] The fourth aspect of the present invention provides a computer program product.

[0032] A computer program product, including a computer program / instructions, and when the computer program / instructions are executed by a processor, it implements the steps in the above-mentioned harmonic liability assessment method based on multi-frequency decoupling.

[0033] The fifth aspect of the present invention provides an electronic device.

[0034] An electronic device, including a memory, a processor, and a computer program stored on the memory and executable on the processor, and when the processor executes the program, it implements the steps in the above-mentioned harmonic liability assessment method based on multi-frequency decoupling.

[0035] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0036] The harmonic liability assessment method and system based on multi-frequency decoupling provided by the present invention use a harmonic coupling model to characterize the user side in a single harmonic source scenario, establish a grid-connected equivalent model of a single harmonic source considering the influence of harmonic coupling, use the grid-connected equivalent model of a single harmonic source to determine the decoupling relationship between the h-th harmonic voltage at the point of common coupling (PCC) on the user side and the user's harmonic current of the same frequency, voltages of other frequencies, and background harmonic voltages, and then determine the evaluation index to describe the dominant influence of the h-th harmonic voltage at the PCC on the system side and the user side, analyze the relationship between the user's harmonic current of the same frequency, other non-harmonic voltages, and the background harmonic voltage on the system side, further determine the dominant disturbance frequency on the basis of traditional identification of the dominant source, solve the limitation that the traditional Norton model can only consider the harmonic emission level of the user side at a single frequency, and more accurately and reliably identify the dominant disturbance frequency by quantifying and comparing the responsibilities of harmonic voltages at each frequency for the voltage distortion at the grid connection point, which can provide a more targeted reference for subsequent targeted treatment.

[0037] The advantages of the additional aspects of the present invention will be partially given in the following description, partially become obvious from the following description, or be understood through the practice of the present invention. Description of the Drawings

[0038] The accompanying drawings forming a part of this invention are used to provide a further understanding of the invention. The schematic embodiments and descriptions thereof of the invention are used to explain the invention and do not unduly limit the invention.

[0039] Figure 1 is a flowchart of a harmonic liability assessment method based on multi-frequency decoupling according to an embodiment of the present invention;

[0040] Figure 2 is an equivalent circuit diagram for 7th harmonic analysis based on harmonic coupling admittance according to an embodiment of the present invention;

[0041] Figure 3 is a decoupled responsibility vector diagram of the 7th harmonic voltage in the frequency domain at the PCC according to an embodiment of the present invention;

[0042] Figure 4 is the quantitative assessment result of harmonic traceability across frequencies of each harmonic voltage according to an embodiment of the present invention;

[0043] Figure 5 is a schematic structural diagram of an electronic device according to an embodiment of the present invention;

[0044] Figure 6 is a schematic structural diagram of a harmonic liability assessment system based on multi-frequency decoupling according to an embodiment of the present invention. Detailed Embodiments

[0045] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0046] It should be noted that the following detailed descriptions are all illustrative and are intended to provide a further description of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present invention belongs.

[0047] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular forms are also intended to include the plural forms. In addition, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0048] Embodiment 1

[0049] Referring to Figure 1 , an embodiment of the present invention provides a harmonic liability assessment method based on multi-frequency decoupling, which includes:

[0050] S101: Take the node to be evaluated for harmonic tracing as the concerned node. Based on the harmonic voltage data and harmonic current data of the concerned node at the harmonic frequencies considered during the pre-determined evaluation period, establish a harmonic coupling model on the user side, and then construct a single harmonic source grid-connected equivalent model considering the influence of harmonic coupling.

[0051] Select the node to be evaluated for harmonic liability as the concerned node, i.e., the PCC. Select the evaluation period and the harmonic order. The length of the evaluation period can be chosen as 15 minutes. Obtain the harmonic voltage data and harmonic current data of the concerned node at the harmonic frequencies considered during the selected period. Establish a harmonic coupling model on the user side and construct a single harmonic source grid-connected equivalent model considering the influence of harmonic coupling.

[0052] The step of selecting the node to be evaluated for harmonic liability as the concerned node and constructing the harmonic coupling model on the user side is shown in Equation (1).

[0053]

[0054] Where, I PCC is the matrix composed of currents at each frequency; is the h-th harmonic current at the PCC; V PCC is the matrix composed of voltages at each frequency; is the k-th harmonic voltage at the PCC; Y h,k is the influence coefficient of the k-th harmonic voltage on the h-th harmonic current. Y h,k can be equivalent to admittance. Y is the harmonic coupling admittance matrix representing the multi-frequency harmonic coupling relationship. The larger the magnitude of Y h,k , the higher the coupling degree. H is the highest harmonic order considered.

[0055] The harmonic coupling model established for the PCC can decouple the influence of harmonic voltages at each frequency on harmonic currents. To describe the h-th harmonic current generated when the fundamental voltage and harmonic voltages are applied to nonlinear power electronic devices, Equation (1) can be simplified to the following form:

[0056]

[0057] Taking the fundamental frequency and the 5th, 7th, and 11th harmonics as the harmonic orders considered, the equivalent circuit for the 7th harmonic analysis based on the harmonic coupling model on the user side is as Figure 2 shown. Where, is the h-th harmonic equivalent voltage source on the system side; Z S,h is the h-th harmonic equivalent impedance on the system side of the PCC, is the h-th harmonic equivalent current source on the user side.

[0058] For the same-frequency harmonics, the harmonic current source remains constant and can be calculated in the following way:

[0059]

[0060] Wherein, t1 and t2 respectively represent any two moments within the time period participating in the evaluation. and respectively represent the harmonic current values at the moments of t1 and t2. and respectively represent the harmonic voltage values at the moments of t1 and t2.

[0061] For non - co - frequency harmonics, the h - th harmonic equivalent current source is a controlled current source, and it has the following relationship with the harmonic voltage at the PPC and each element Y in the harmonic coupling model matrix i,j :

[0062]

[0063] The present invention considers the coupling relationship between cross - frequency harmonic voltages and harmonic currents, uses the harmonic coupling model to establish the coupling admittance model on the user side, and introduces the effect of each - order voltage at the concerned node on the harmonic current of the user equipment by each element of the frequency - domain coupling admittance matrix, thereby constructing a single - harmonic - source grid - connected equivalent model based on frequency - domain coupling, and solving the limitation that the traditional Norton model can only consider the harmonic emission level on the user side at a single frequency.

[0064] S102: Based on the single - harmonic - source grid - connected equivalent model, obtain the decoupling relationship between the h - th harmonic voltage at the point of common coupling (PCC) on the user side and the user's same - frequency harmonic current, other - frequency voltages, and background harmonic voltages, and then obtain the evaluation index according to the projection of each - order harmonic voltage on the h - th harmonic voltage at the PCC on the user side.

[0065] According to the evaluation index, further clarify the harmonic responsibility, that is, the harmonic source, under the coupling of each - order voltage and each - order current considering the influence of background harmonics.

[0066] According to Kirchhoff's law and the superposition theorem, Figure 2 the 7 - th harmonic voltage at the PCC in

[0067]

[0068] can be further sorted out to obtain:

[0069]

[0070] Wherein, Y S,7 is the 7 - th harmonic equivalent admittance on the system side, and it is reciprocal to the 7 - th harmonic impedance Z S,7 on the system side.

[0071] Thus, the functional relationships between the harmonic voltage at the point of common coupling (PCC), the harmonic current of the same frequency of the user, the voltage of other frequencies, and the background harmonic voltage are established. The meaning represented by each component can be traced back to the harmonic voltage of each order and the influence of the harmonic current of the user side itself on the 7th harmonic current of the user side, thereby clarifying the impact on the 7th voltage distortion at the PCC.

[0072] Further generalization can be extended to the influence of all harmonic frequencies, and the decoupling relationship of the hth harmonic voltage at the PCC is obtained:

[0073]

[0074] where, is the hth harmonic voltage at the PCC on the user side; C h,k is the influence coefficient of the kth harmonic voltage of different frequencies, and k≠h; is the kth harmonic voltage at the PCC on the user side; C I,h is the influence coefficient of the harmonic current source of the same frequency on the user side; is the equivalent current source of the hth harmonic on the user side; C S,h is the influence coefficient of the background harmonic voltage of the same frequency on the background side; is the equivalent voltage source of the hth harmonic on the system side; Y h,h is the influence coefficient of the harmonic current source of the same frequency on the user side on the hth harmonic current; Y S,h is the influence coefficient of the background harmonic voltage of the same frequency on the background side on the hth harmonic current; H is the harmonic order.

[0075] Among them, the evaluation indexes include: the projection of the background harmonic of the same frequency on the system side on the hth harmonic voltage at the PCC on the user side, the projection of the harmonic of the same frequency on the user side on the hth harmonic voltage at the PCC on the user side, and the projection of the kth harmonic voltage on the user side on the hth harmonic voltage at the PCC on the user side.

[0076] The projection of the harmonic voltage of each frequency on the hth harmonic voltage at the PCC on the user side is:

[0077]

[0078] where, is the hth harmonic voltage at the PCC on the user side; H h,k is the projection of the kth harmonic voltage on the user side on the hth harmonic voltage at the PCC on the user side, and k≠h; H I,h is the projection of the harmonic of the same frequency on the user side on the hth harmonic voltage at the PCC on the user side; H S,h is the projection of the background harmonic of the same frequency on the system side on the hth harmonic voltage at the PCC on the user side; C h,k is the influence coefficient of the kth harmonic voltage of different frequencies, and k≠h; is the k-th harmonic voltage at the point of common coupling on the user side; cos is the cosine function; C I,h is the influence coefficient of the in-phase harmonic current source on the user side; is the equivalent current source of the h-th harmonic on the user side; C S,h is the influence coefficient of the in-phase background harmonic voltage on the background side; is the equivalent voltage source of the h-th harmonic on the system side.

[0079] Taking the 7th harmonic voltage at the PCC as an example, the multi-frequency responsibility decoupling vector diagram is as Figure 3 shown. In traditional harmonic modeling and responsibility assessment, the user side is regarded as the form of a constant current source in parallel with a admittance, which is equivalent to believing that the distortion of the PCC harmonic voltage comes from the influence of the user side harmonic current source and the in-phase background voltage, without considering the mutual coupling influence between harmonics of each order. Therefore, there is no distinction in the contribution of the fundamental wave and harmonic voltages of other frequencies. As Figure 3 can be seen, the traditional harmonic tracing quantitative assessment method cannot quantify the proportion of (H 7,1 +H 7,7 +H 7,11 +H I,7 ), so it is impossible to clarify the specific influence of harmonics of different frequencies, and only the responsibility ratio between the user side and the system side can be distinguished. Compared with the traditional method, the proposed method can describe the dominant influence of the h-th harmonic voltage at the PCC between the system side and the user side, and analyze the relationship between the in-phase harmonic current on the user side, other non-in-phase voltages, and the background harmonic voltage on the system side.

[0080] The present invention establishes the coupling relationship between the single-harmonic distortion at the concerned node and voltages of other frequencies, and proposes a harmonic tracing method considering multi-frequency coupling influence. By quantifying and comparing the responsibilities of harmonic voltages of each frequency for the voltage distortion at the grid connection point, it can more accurately and reliably identify the dominant disturbance frequency on the basis of traditional identification of the dominant source, and can provide a more targeted reference for subsequent targeted treatment.

[0081] S103: According to the evaluation index, respectively quantify the contribution levels of the in-phase harmonic current source on the user side, the harmonic voltages of non-in-phase frequencies, and the in-phase background harmonic voltage on the system side to the harmonic voltage at the concerned node, and obtain the harmonic tracing quantitative assessment result, as Figure 4 shown, to identify the dominant harmonic frequency.

[0082] If the projection of the in-phase background harmonic on the system side on the h-th harmonic voltage at the point of common coupling on the user side is greater than the projection of all frequencies on the user side on the h-th harmonic voltage at the point of common coupling on the user side, it is determined that the dominant source of the harmonic is the system side;

[0083] If the projection of the h -th harmonic current source on the user side at the point of common coupling (PCC) is greater than the projections of other frequencies on the user side at the h -th harmonic voltage at the PCC, and at the same time greater than the projection of the background harmonics on the user side at the h -th harmonic voltage at the PCC, then it is determined that the dominant source of harmonics is the harmonic source on the user side.

[0084] If the projection of the k -th harmonic voltage on the user side at the h -th harmonic voltage at the PCC is greater than the projections of other frequencies on the user side at the h -th harmonic voltage at the PCC, and at the same time greater than the projection of the background harmonics on the user side at the h -th harmonic voltage at the PCC, then it is determined that the dominant source of harmonics is the user side, and the dominant frequency is the k -th harmonic on the user side.

[0085] On the one hand, the harmonic responsibility assessment method based on multi - frequency decoupling of the present invention can refine the responsibility that the equipment on the user side should bear for the distortion at the PCC after generating and responding to each harmonic voltage, and further clarify the harmonic source and generation mechanism. On the other hand, it can intuitively reflect the coupling relationship between the distortion of the single - frequency harmonic voltage at the PCC and the voltages of other frequencies, providing a basis for formulating the next - step harmonic control and management measures for each frequency.

[0086] Embodiment 2

[0087] This embodiment provides a computer - readable storage medium, on which a computer program is stored. When the program is executed by a processor, it implements the steps in the harmonic responsibility assessment method based on multi - frequency decoupling as described in Embodiment 1 above.

[0088] Embodiment 3

[0089] This embodiment provides a computer program product, including a computer program / instructions. When the computer program / instructions are executed by a processor, they implement the steps in the harmonic responsibility assessment method based on multi - frequency decoupling as described in Embodiment 1 above.

[0090] Embodiment 4

[0091] This embodiment provides an electronic device, including a memory, a processor, and a computer program stored on the memory and executable on the processor. When the processor executes the program, it implements the steps in the harmonic responsibility assessment method based on multi - frequency decoupling as described above.

[0092] Refer to Figure 5 , a schematic structural diagram of the electronic device in this embodiment. It should be noted that Figure 5 The illustrated electronic device 500 is only an example and should not bring any limitations to the functions and usage scope of the embodiments of the present invention.

[0093] As Figure 5As shown, the electronic device 500 includes a central processing unit (CPU) 501, which can perform various appropriate actions and processes according to the programs stored in the read-only memory (ROM) 502 or the programs loaded from the storage section 508 into the random access memory (RAM) 503. In the RAM 503, various programs and data required for system operation are also stored. The central processing unit 501, the ROM 502, and the RAM 503 are connected to each other via a bus 504. An input / output (I / O) interface 505 is also connected to the bus 504.

[0094] The following components are connected to the I / O interface 505: an input section 506 including a keyboard, a mouse, etc.; an output section 507 including a cathode ray tube (CRT), a liquid crystal display (LCD), etc. and a speaker, etc.; a storage section 508 including a hard disk, etc.; and a communication section 509 including a network interface card such as a local area network (LAN) card, a modem, etc. The communication section 509 performs communication processing via a network such as the Internet. A drive 510 is also connected to the I / O interface 505 as needed. A removable medium 511, such as a magnetic disk, an optical disk, a magneto-optical disk, a semiconductor memory, etc., is installed on the drive 510 as needed so that a computer program read from it can be installed into the storage section 508 as needed.

[0095] Specifically, according to an embodiment of the present application, the process described above with reference to the flowchart can be implemented as a computer software program. For example, an embodiment of the present application includes a computer program product, which includes a computer program carried on a computer-readable medium, and the computer program contains program codes for executing the method shown in the flowchart. In such an embodiment, the computer program can be downloaded and installed from the network through the communication section 509, and / or installed from the removable medium 511. When the computer program is executed by the central processing unit 501, various functions defined in the device of the present application are executed.

[0096] The present invention is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products of the embodiments of the present invention. It should be understood that each flow and / or block in the flowcharts and / or block diagrams, and the combination of flows and / or blocks in the flowcharts and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to the processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing devices to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing devices generate a device for realizing the functions specified in Figure 1 one flow or multiple flows and / or blocks Figure 1 one block or multiple blocks.

[0097] Embodiment Five

[0098] As Figure 6 shown, the embodiment of the present invention provides a harmonic liability assessment system based on multi-frequency decoupling, which includes:

[0099] A single harmonic source grid-connected equivalent model construction module 601, which is used to take the node to be evaluated for harmonic traceability as the concerned node, and based on the harmonic voltage data and harmonic current data of the concerned node at the harmonic frequencies considered during the pre-determined evaluation period, establish a user-side harmonic coupling model, and then construct a single harmonic source grid-connected equivalent model considering the influence of harmonic coupling;

[0100] An evaluation index determination module 602, which is used to obtain the decoupling relationship between the h-th harmonic voltage at the point of common coupling on the user side and the harmonic current of the same frequency of the user, voltages of other frequencies, and background harmonic voltage based on the single harmonic source grid-connected equivalent model, and then obtain the evaluation index according to the projection of the harmonic voltages of each frequency on the h-th harmonic voltage at the point of common coupling on the user side;

[0101] A quantitative evaluation result calculation module 603, which is used to quantify the contribution levels of the harmonic current source of the same frequency on the user side, the harmonic voltage of non-same frequencies, and the background harmonic voltage of the same frequency on the system side to the harmonic voltage at the concerned node according to the evaluation index, and obtain the quantitative evaluation result of harmonic traceability to identify the dominant harmonic frequency.

[0102] It should be noted here that each module in the embodiment of the present invention corresponds to each step in the first embodiment above, and the specific implementation process is the same, so it will not be elaborated here.

[0103] The above are only the preferred embodiments of the present invention and are not used to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A harmonic liability assessment method based on multi-frequency decoupling, characterized in that, Including: Taking the node to be evaluated for harmonic tracing as the concerned node, based on the harmonic voltage data and harmonic current data of the concerned node at the harmonic frequencies considered during the pre-determined evaluation period, establishing a user-side harmonic coupling model, and then constructing a single harmonic source grid-connected equivalent model considering the influence of harmonic coupling; Based on the single harmonic source grid-connected equivalent model, obtaining the decoupling relationship between the h-th harmonic voltage at the point of common coupling on the user side and the user's harmonic current at the same frequency, voltages at other frequencies, and background harmonic voltage, and then obtaining the evaluation index according to the projection of the harmonic voltages at each frequency on the h-th harmonic voltage at the point of common coupling on the user side; According to the evaluation index, respectively quantifying the contribution levels of the user-side harmonic current source at the same frequency, non-harmonic voltages at different frequencies, and the system-side harmonic voltage at the same frequency in the background to the harmonic voltage at the concerned node, obtaining the quantitative evaluation result of harmonic tracing to identify the dominant harmonic frequency.

2. The harmonic liability assessment method based on multi-frequency decoupling according to claim 1, wherein The evaluation index includes: the projection amount of the system-side harmonic voltage at the same frequency in the background on the h-th harmonic voltage at the point of common coupling on the user side, the projection amount of the user's harmonic current at the same frequency on the h-th harmonic voltage at the point of common coupling on the user side, and the projection amount of the user's k-th harmonic voltage on the h-th harmonic voltage at the point of common coupling on the user side.

3. The harmonic liability assessment method based on multi-frequency decoupling according to claim 1 or 2, characterized in that The projection of the harmonic voltages at each frequency on the h-th harmonic voltage at the point of common coupling on the user side is: Among them, is the h - th harmonic voltage at the common coupling point on the user side; H h,k is the projection of the k - th harmonic voltage on the user side onto the h - th harmonic voltage at the common coupling point on the user side, and k≠h; H I,h is the projection of the harmonic voltage of the same frequency on the user side onto the h - th harmonic voltage at the common coupling point on the user side; H S,h is the projection of the background harmonic voltage of the same frequency on the system side onto the h - th harmonic voltage at the common coupling point on the user side; C h,k is the influence coefficient of the non - same - frequency k - th harmonic voltage, and k≠h; is the k - th harmonic voltage at the common coupling point on the user side; cos is the cosine function; C I,h is the influence coefficient of the harmonic current source of the same frequency on the user side; is the equivalent current source of the h - th harmonic on the user side; C S,h is the influence coefficient of the background harmonic voltage of the same frequency on the background side; is the equivalent voltage source of the h - th harmonic on the system side.

4. The harmonic liability assessment method based on multi-frequency decoupling according to claim 1 or 2, characterized in that, The decoupling relationship between the h-th harmonic voltage at the point of common coupling on the user side and the user's harmonic current at the same frequency, voltages at other frequencies, and background harmonic voltage is: Among them, is the h - th harmonic voltage at the common coupling point on the user side; C h,k is the influence coefficient of the non - co - frequency k - th harmonic voltage, and k≠h; is the k - th harmonic voltage at the common coupling point on the user side; C I,h is the influence coefficient of the co - frequency harmonic current source on the user side; is the equivalent current source of the h - th harmonic on the user side; C S,h is the influence coefficient of the co - frequency background harmonic voltage on the background side; is the equivalent voltage source of the h - th harmonic on the system side; Y h,h is the influence coefficient of the co - frequency harmonic current source on the user side on the h - th harmonic current; Y S,h is the influence coefficient of the co - frequency background harmonic voltage on the background side on the h - th harmonic current; H is the harmonic order.

5. The harmonic liability assessment method based on multi-frequency decoupling according to claim 1, wherein, If the projection amount of the system-side harmonic voltage at the same frequency in the background on the h-th harmonic voltage at the point of common coupling on the user side is greater than the projection amounts of all frequencies on the user side on the h-th harmonic voltage at the point of common coupling on the user side, it is determined that the dominant source of harmonics is the system side; Or if the projection amount of the user-side harmonic current source on the h-th harmonic voltage at the point of common coupling on the user side is greater than the projection amounts of other frequencies on the user side on the h-th harmonic voltage at the point of common coupling on the user side, and at the same time greater than the projection amount of the user-side background harmonic on the h-th harmonic voltage at the point of common coupling on the user side, it is determined that the dominant source of harmonics is the user-side harmonic source.

6. The harmonic liability assessment method based on multi-frequency decoupling according to claim 1, characterized in that If the projection amount of the user's k-th harmonic voltage on the h-th harmonic voltage at the point of common coupling on the user side is greater than the projection amounts of other frequencies on the user side on the h-th harmonic voltage at the point of common coupling on the user side, and at the same time greater than the projection amount of the user-side background harmonic on the h-th harmonic voltage at the point of common coupling on the user side, it is determined that the dominant source of harmonics is the user side, and the dominant frequency is the user's k-th harmonic.

7. A harmonic liability assessment system based on multi-frequency decoupling, characterized in that, Including: A single harmonic source grid-connected equivalent model construction module, which is used to take the node to be evaluated for harmonic tracing as the concerned node, based on the harmonic voltage data and harmonic current data of the concerned node at the harmonic frequencies considered during the pre-determined evaluation period, establish a user-side harmonic coupling model, and then construct a single harmonic source grid-connected equivalent model considering the influence of harmonic coupling; An evaluation index determination module, which is used to obtain the decoupling relationship between the h-th harmonic voltage at the point of common coupling on the user side and the user's harmonic current at the same frequency, voltages at other frequencies, and background harmonic voltage based on the single harmonic source grid-connected equivalent model, and then obtain the evaluation index according to the projection of the harmonic voltages at each frequency on the h-th harmonic voltage at the point of common coupling on the user side; A quantitative evaluation result calculation module, which is used to quantify the contribution levels of the user-side in-phase harmonic current source, out-of-phase harmonic voltage, and the system-side in-phase background harmonic voltage to the harmonic voltage at the concerned node respectively according to the evaluation index, so as to obtain a quantitative evaluation result of harmonic tracing to identify the dominant harmonic frequency.

8. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the program is executed by a processor, it implements the steps in the multi-frequency decoupling-based harmonic liability assessment method according to any one of claims 1-6.

9. A computer program product, comprising a computer program / instructions, characterized in that, When the computer program / instructions are executed by a processor, it implements the steps in the multi-frequency decoupling-based harmonic liability assessment method according to any one of claims 1-6.

10. An electronic device, comprising a memory, a processor, and a computer program stored on the memory and executable on the processor, characterized in that, When the processor executes the program, it implements the steps in the multi-frequency decoupling-based harmonic liability assessment method according to any one of claims 1-6.

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