Difference evaluation method and device for influence of grid connection intensity on impedance of new energy station

Abstract

The invention provides a difference evaluation method and device for influence of grid connection intensity on impedance of a new energy field station, and relates to the technical field of new energy. The method comprises the following steps: acquiring a reference impedance real part value of a secondary diagonal element under a historical amplitude-frequency oscillation voltage when a new energy grid-connected strength improvement strategy is not adopted, and acquiring a to-be-compared impedance real part value of the secondary diagonal element under the historical amplitude-frequency oscillation voltage when at least one new energy grid-connected strength improvement strategy is adopted; and randomly selecting one reference impedance real part value and the impedance real part value to be compared of the corresponding position element to carry out numerical comparison, and determining a difference evaluation result of the influence of the new energy grid-connected strength improvement strategy on the impedance of the new energy field station according to a first comparison result. The device executes the method. According to the method and the device provided by the embodiment of the invention, the difference evaluation of the influence of the grid-connected strength on the impedance of the new energy field station can be comprehensively and accurately realized.

Description

Technical Field

[0001] The present invention relates to the field of new energy technology, and in particular to a method and device for evaluating the difference in the impact of grid connection strength on the impedance of a new energy station. Background Art

[0002] With the increasing reliance on renewable energy, the proportion of new energy sites (such as wind farms and photovoltaic power plants) in the power system continues to rise. However, there are significant differences in the way new energy sites are connected to the grid from traditional power generation units, mainly reflected in their power supply characteristics with weaker damping and smaller inertia. This characteristic makes it easy for new energy sites to cause amplitude-frequency modulation oscillation when facing grid disturbances, which in turn affects the stable operation of the system.

[0003] AFM oscillation refers to the frequency and voltage fluctuations in the power system caused by various factors (such as load changes, network congestion, output fluctuations of new energy stations, etc.). Such fluctuations may lead to unstable power output of new energy stations and even cause system oscillations, threatening the safe and stable operation of the power grid.

[0004] The existing strategies for improving grid connection strength mainly include increasing synchronous generators, adopting virtual synchronous machine technology, and applying grid-type unit control strategies, installed capacity and access location, phase-shifting machine access location, capacity, and quantity. Although these strategies can improve the impedance characteristics of new energy stations to a certain extent, their effects and applicability vary significantly under different grid conditions. Therefore, the difference in impedance matrix elements can also reflect the difference in grid connection strength to determine its specific impact on new energy stations. At present, there is a mature theory for the calculation research scheme of the main diagonal elements of the impedance matrix. Regardless of sub-synchronous oscillation, super-synchronous oscillation, or amplitude-frequency modulation oscillation, the existing methods can achieve accurate measurement of the main diagonal elements of the impedance matrix. However, there is no effective measurement method for the accurate measurement of the sub-diagonal elements of the impedance matrix, which makes the difference in the impact of grid connection strength on the impedance of new energy stations not comprehensive and accurate. Summary of the invention

[0005] In view of the problems in the prior art, an embodiment of the present invention provides a method and device for evaluating the difference in the impact of grid connection strength on the impedance of a new energy station, which can at least partially solve the problems in the prior art.

[0006] On the one hand, the present invention proposes a method for evaluating the difference in the impact of grid connection intensity on the impedance of a new energy station, comprising:

[0007] Obtaining the real part value of the reference impedance of the sub-diagonal element under the historical amplitude-frequency oscillation voltage when the strategy for improving the grid connection strength of new energy is not adopted, and obtaining the real part value of the impedance to be compared of the sub-diagonal element under the historical amplitude-frequency oscillation voltage when at least one strategy for improving the grid connection strength of new energy is adopted;

[0008] A real part value of a benchmark impedance is arbitrarily selected to be numerically compared with the real part value of the impedance to be compared of the element at the corresponding position, and a difference evaluation result of the impact of the new energy grid-connected intensity improvement strategy on the impedance of the new energy site is determined according to the first comparison result.

[0009] The obtaining of the real part value of the reference impedance of the sub-diagonal element under the historical amplitude-frequency oscillation voltage when the new energy grid connection strength improvement strategy is not adopted includes:

[0010] Subsynchronous voltage excitation signals and supersynchronous voltage excitation signals are respectively applied to the new energy grid connection points that do not adopt the new energy grid connection strength improvement strategy, and the amplitude and phase of the sub-diagonal elements of the reference impedance matrix are calculated;

[0011] Calculate the real part value of the reference impedance according to the amplitude and phase of the sub-diagonal elements of the reference impedance matrix, and the pre-obtained reference first initial phase, reference second initial phase, reference third initial phase and reference fourth initial phase;

[0012] Among them, the reference first initial phase corresponds to the reference voltage amplitude response signal, the reference second initial phase corresponds to the reference voltage frequency response signal, the reference third initial phase corresponds to the reference voltage amplitude measurement signal of the historical oscillation event, and the reference fourth initial phase corresponds to the reference voltage frequency measurement signal of the historical oscillation event.

[0013] The sub-synchronous voltage excitation signal and the super-synchronous voltage excitation signal are respectively applied to the new energy grid connection points that do not adopt the new energy grid connection strength improvement strategy, and the amplitude and phase of the sub-diagonal elements of the reference impedance matrix are calculated, including:

[0014] When applying the sub-synchronous voltage excitation signal, obtaining a reference first induced voltage and a reference first induced current associated with a reference first diagonal element;

[0015] Determining the amplitude and phase of the first diagonal element of the reference impedance matrix according to the ratio of the reference first induced voltage to the reference first induced current;

[0016] When applying the super-synchronous voltage excitation signal, obtaining a reference second induced voltage and a reference second induced current associated with the reference second diagonal element;

[0017] The amplitude and phase of the second sub-diagonal elements of the reference impedance matrix are determined according to the ratio of the reference second induced voltage to the reference second induced current.

[0018] The step of obtaining the real part value of the impedance to be compared of the sub-diagonal element under the historical amplitude-frequency oscillation voltage when adopting at least one new energy grid-connected strength improvement strategy includes:

[0019] Applying a subsynchronous voltage excitation signal and a supersynchronous voltage excitation signal to a new energy grid connection point that adopts at least one new energy grid connection strength improvement strategy, respectively, and calculating the amplitude and phase of the sub-diagonal elements of the impedance matrix to be compared;

[0020] Calculate the real part value of the impedance to be compared according to the amplitude and phase of the sub-diagonal elements of the impedance matrix to be compared, and the pre-obtained first initial phase to be compared, the second initial phase to be compared, the third initial phase to be compared, and the fourth initial phase to be compared;

[0021] Among them, the first initial phase to be compared corresponds to the voltage amplitude response signal to be compared, the second initial phase to be compared corresponds to the voltage frequency response signal to be compared, the third initial phase to be compared corresponds to the voltage amplitude measurement signal to be compared of the historical oscillation event, and the fourth initial phase to be compared corresponds to the voltage frequency measurement signal to be compared of the historical oscillation event.

[0022] The sub-synchronous voltage excitation signal and the super-synchronous voltage excitation signal are respectively applied to the new energy grid connection point adopting at least one new energy grid connection strength improvement strategy, and the amplitude and phase of the sub-diagonal elements of the impedance matrix to be compared are calculated, including:

[0023] When applying the sub-synchronous voltage excitation signal, obtaining a first induced voltage to be compared and a first induced current to be compared related to the first diagonal element to be compared;

[0024] Determining the amplitude and phase of the first sub-diagonal element of the impedance matrix to be compared according to the ratio of the first induced voltage to be compared to the first induced current to be compared;

[0025] When applying the super-synchronous voltage excitation signal, obtaining a second induced voltage to be compared and a second induced current to be compared related to the second diagonal element to be compared;

[0026] The amplitude and phase of the second sub-diagonal element of the impedance matrix to be compared are determined according to the ratio of the second induced voltage to be compared to the second induced current to be compared.

[0027] The difference evaluation result of the impact of the new energy grid connection intensity improvement strategy on the new energy station impedance is determined according to the first comparison result, including:

[0028] The first comparison results are sorted in descending order, and the difference evaluation result is determined according to the sorting order.

[0029] Wherein, after the step of determining the difference evaluation result of the impact of the new energy grid connection strength improvement strategy on the new energy station impedance according to the first comparison result, the difference evaluation method of the impact of the grid connection strength on the new energy station impedance also includes:

[0030] Another reference impedance real part value is selected to perform numerical comparison with the real part value of the impedance to be compared of the element at the corresponding position, and the difference evaluation result is verified according to the second comparison result.

[0031] On the one hand, the present invention proposes a device for evaluating the difference of the impact of grid connection strength on the impedance of a new energy station, comprising:

[0032] An acquisition unit, used to acquire the real part value of the reference impedance of the sub-diagonal element under the historical amplitude-frequency oscillation voltage when the new energy grid-connected strength improvement strategy is not adopted, and to acquire the real part value of the impedance to be compared of the sub-diagonal element under the historical amplitude-frequency oscillation voltage when at least one new energy grid-connected strength improvement strategy is adopted;

[0033] An evaluation unit is used to arbitrarily select a reference impedance real part value and compare it with the real part value of the impedance to be compared of the corresponding position element, and determine the difference evaluation result of the impact of the new energy grid-connected strength improvement strategy on the impedance of the new energy station according to the first comparison result.

[0034] In another aspect, an embodiment of the present invention provides an electronic device, including: a processor, a memory, and a bus, wherein:

[0035] The processor and the memory communicate with each other via the bus;

[0036] The memory stores program instructions that can be executed by the processor, and the processor calls the program instructions to execute the following method:

[0037] Obtaining the real part value of the reference impedance of the sub-diagonal element under the historical amplitude-frequency oscillation voltage when the strategy for improving the grid connection strength of new energy is not adopted, and obtaining the real part value of the impedance to be compared of the sub-diagonal element under the historical amplitude-frequency oscillation voltage when at least one strategy for improving the grid connection strength of new energy is adopted;

[0038] A real part value of a benchmark impedance is arbitrarily selected to be numerically compared with the real part value of the impedance to be compared of the element at the corresponding position, and a difference evaluation result of the impact of the new energy grid-connected intensity improvement strategy on the impedance of the new energy site is determined according to the first comparison result.

[0039] An embodiment of the present invention provides a non-transitory computer-readable storage medium, including:

[0040] The non-transitory computer-readable storage medium stores computer instructions, which cause the computer to execute the following method:

[0041] Obtaining the real part value of the reference impedance of the sub-diagonal element under the historical amplitude-frequency oscillation voltage when the strategy for improving the grid connection strength of new energy is not adopted, and obtaining the real part value of the impedance to be compared of the sub-diagonal element under the historical amplitude-frequency oscillation voltage when at least one strategy for improving the grid connection strength of new energy is adopted;

[0042] A real part value of a benchmark impedance is arbitrarily selected to be numerically compared with the real part value of the impedance to be compared of the element at the corresponding position, and a difference evaluation result of the impact of the new energy grid-connected intensity improvement strategy on the impedance of the new energy site is determined according to the first comparison result.

[0043] The embodiment of the present invention provides a method and device for evaluating the difference in the impact of grid connection strength on the impedance of a new energy station, which obtains the real part value of the reference impedance of the sub-diagonal elements under the historical amplitude-frequency oscillation voltage when the new energy grid connection strength improvement strategy is not adopted, and obtains the real part value of the impedance to be compared of the sub-diagonal elements under the historical amplitude-frequency oscillation voltage when at least one new energy grid connection strength improvement strategy is adopted; arbitrarily selects a reference impedance real part value and the real part value of the impedance to be compared of the element at the corresponding position for numerical comparison, and determines the difference evaluation result of the impact of the new energy grid connection strength improvement strategy on the impedance of the new energy station according to the first comparison result. By accurately calculating the relevant values ​​of the sub-diagonal elements of the impedance matrix, the difference evaluation of the impact of the grid connection strength on the impedance of the new energy station can be fully and accurately achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the prior art descriptions. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work. In the drawings:

[0045] Figure 1 It is a flow chart of a method for evaluating the difference in the impact of grid connection strength on the impedance of a new energy station provided by an embodiment of the present invention.

[0046] Figure 2 It is a schematic diagram illustrating the electromagnetic transient simulation model provided by an embodiment of the present invention.

[0047] Figure 3 It is a schematic diagram illustrating the active power of the unit after applying 7 Hz oscillation provided by an embodiment of the present invention.

[0048] Figure 4It is a schematic diagram illustrating the reactive power of the unit after applying 7 Hz oscillation provided by an embodiment of the present invention.

[0049] Figure 5 It is a flow chart of a method for evaluating the difference in the impact of grid connection strength on the impedance of a new energy station provided by another embodiment of the present invention.

[0050] Figure 6 It is a structural schematic diagram of a device for evaluating the difference in the impact of grid connection strength on the impedance of a new energy station provided by an embodiment of the present invention.

[0051] Figure 7 A schematic diagram of the physical structure of an electronic device provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0052] In order to make the purpose, technical scheme and advantages of the embodiments of the present invention more clear, the embodiments of the present invention are further described in detail below in conjunction with the accompanying drawings. Here, the illustrative embodiments of the present invention and their descriptions are used to explain the present invention, but are not intended to limit the present invention. It should be noted that, in the absence of conflict, the embodiments in this application and the features in the embodiments can be combined with each other arbitrarily.

[0053] Figure 1 : is a flow chart of a method for evaluating the difference in the impact of grid connection strength on the impedance of a new energy station provided by an embodiment of the present invention. Figure 1 As shown, the method for evaluating the difference in the impact of grid connection strength on the impedance of a new energy station provided by an embodiment of the present invention includes:

[0054] Step S1: Obtain the real part value of the baseline impedance of the sub-diagonal element under the historical amplitude-frequency oscillation voltage when the new energy grid-connected strength improvement strategy is not adopted, and obtain the real part value of the impedance to be compared of the sub-diagonal element under the historical amplitude-frequency oscillation voltage when at least one new energy grid-connected strength improvement strategy is adopted.

[0055] Step S2: arbitrarily select a reference impedance real part value and compare it with the real part value of the impedance to be compared of the element at the corresponding position, and determine the difference evaluation result of the impact of the new energy grid-connected strength improvement strategy on the new energy station impedance according to the first comparison result.

[0056] In the above step S1, the device obtains the real part value of the reference impedance of the sub-diagonal element under the historical amplitude-frequency oscillation voltage when the new energy grid connection strength improvement strategy is not adopted, and obtains the real part value of the impedance to be compared of the sub-diagonal element under the historical amplitude-frequency oscillation voltage when at least one new energy grid connection strength improvement strategy is adopted. The device can be a computer device that executes the method. The new energy grid connection strength improvement strategy can include the application of grid-type unit grid control strategy; installed capacity ratio and access location; phase-shifting machine access location, capacity, quantity, etc.

[0057] The obtaining of the real part value of the reference impedance of the sub-diagonal element under the historical amplitude-frequency oscillation voltage when the new energy grid connection strength improvement strategy is not adopted includes:

[0058] Subsynchronous voltage excitation signals and supersynchronous voltage excitation signals are respectively applied to the new energy grid connection points that do not adopt the new energy grid connection strength improvement strategy, and the amplitude and phase of the sub-diagonal elements of the reference impedance matrix are calculated;

[0059] Calculate the real part value of the reference impedance according to the amplitude and phase of the sub-diagonal elements of the reference impedance matrix, and the pre-obtained reference first initial phase, reference second initial phase, reference third initial phase and reference fourth initial phase;

[0060] Among them, the reference first initial phase corresponds to the reference voltage amplitude response signal, the reference second initial phase corresponds to the reference voltage frequency response signal, the reference third initial phase corresponds to the reference voltage amplitude measurement signal of the historical oscillation event, and the reference fourth initial phase corresponds to the reference voltage frequency measurement signal of the historical oscillation event.

[0061] The sub-synchronous voltage excitation signal and the super-synchronous voltage excitation signal are respectively applied to the new energy grid connection point that does not adopt the new energy grid connection strength improvement strategy, and the amplitude and phase of the sub-diagonal elements of the reference impedance matrix are calculated, including:

[0062] When applying the sub-synchronous voltage excitation signal, obtaining a reference first induced voltage and a reference first induced current associated with a reference first diagonal element;

[0063] Determining the amplitude and phase of the first diagonal element of the reference impedance matrix according to the ratio of the reference first induced voltage to the reference first induced current;

[0064] When applying the super-synchronous voltage excitation signal, obtaining a reference second induced voltage and a reference second induced current associated with the reference second diagonal element;

[0065] The amplitude and phase of the second sub-diagonal elements of the reference impedance matrix are determined according to the ratio of the reference second induced voltage to the reference second induced current.

[0066] like Figure 2 As shown, the impact of grid-connected strength differences can be evaluated and verified based on this electromagnetic transient simulation model, where the wind turbine is a direct-drive wind turbine.

[0067] Taking the application of 7Hz oscillation as an example for verification, the active power of the unit after applying 7Hz oscillation is as follows: Figure 3 As shown, after applying 7Hz oscillation, the reactive power of the unit is as follows Figure 4 shown.

[0068] Sub- and super-synchronous voltage excitation signals are applied respectively, and the four impedance elements of the initial impedance matrix are measured (taking the application of sub- and super-synchronous voltage excitation signals of 43 Hz and 57 Hz as an example):

[0069] When the voltage signal When excited alone, a 43Hz current will be induced With 57Hz current The two are measured and the relevant elements of the impedance matrix are calculated as follows:

[0070]

[0071] in, is the reference first induced voltage, is the reference first induction current, Z 21 is the magnitude of the first diagonal element, is the phase of the first diagonal element.

[0072] For example, the calculated result is Z 11 =30.96Ω, Z 21 =2577.39Ω,

[0073] When the voltage signal When excited alone, a 43Hz current will be induced With 57Hz current The two are measured and the relevant elements of the impedance matrix are calculated as follows:

[0074]

[0075] in, is the reference second induced voltage, is the reference second induction current, Z 12 is the magnitude of the second diagonal element, is the phase of the second diagonal elements.

[0076] For example, the calculated result is Z 12 =769.23Ω, Z 22 =357.1428Ω,

[0077] Obtaining a reference first initial phase phi1 and a reference second initial phase phi2 includes:

[0078] Based on the subsynchronous voltage excitation signal and supersynchronous voltage excitation signal applied above, the subsynchronous voltage response signal and supersynchronous voltage response signal of the new energy grid-connected point are obtained. After converting these two response signals into voltage amplitude and voltage frequency modulation response signals, phi1 corresponding to the reference voltage amplitude response signal and phi2 corresponding to the reference voltage frequency response signal are obtained by measurement.

[0079] Obtaining a reference third initial phase phi3 and a reference fourth initial phase phi4 includes:

[0080] The voltage amplitude-frequency modulation oscillation signal at the renewable energy grid connection point in the historical oscillation event is decomposed into amplitude and frequency modulation signals; the initial phases phi3 and phi4 of the voltage amplitude and frequency modulation signals are measured respectively, as follows:

[0081] This step assumes that the oscillation event is caused by voltage amplitude-frequency modulation oscillation, and decomposes the voltage amplitude-frequency modulation oscillation signal at the new energy grid-connected point in the oscillation event into amplitude and frequency modulation signals, and measures phi3 corresponding to the reference voltage amplitude measurement signal of the historical oscillation event and phi4 corresponding to the reference voltage frequency measurement signal of the historical oscillation event respectively.

[0082] In the above step S2, the device arbitrarily selects a reference impedance real part value and the real part value of the impedance to be compared of the corresponding position element for numerical comparison, and determines the difference evaluation result of the impact of the new energy grid-connected strength improvement strategy on the new energy station impedance according to the first comparison result.

[0083] The amplitude and phase of the sub-diagonal elements of the reference impedance matrix, as well as the reference first initial phase, the reference second initial phase, the reference third initial phase and the reference fourth initial phase, can be input into the matlab tool, and the amplitude and phase of the sub-diagonal elements under the historical amplitude-frequency oscillation voltage can be obtained by calling the relevant calculation module, and then the real part value of the reference impedance can be calculated according to the above amplitude and phase. For example, the amplitude of the two sub-diagonal impedance elements is: Z 12 =769.23W and Z 21 =2577.39W, the phase is: and Z 12 For example, its actual value is 763.85W.

[0084] For the situation when at least one strategy for improving the grid-connected intensity of new energy is adopted, you can refer to the above description of the situation when no strategy for improving the grid-connected intensity of new energy is adopted, and no further details will be given.

[0085] like Figure 5 As shown, the way to improve the grid connection strength is changed, that is, a variety of new energy grid connection strength improvement strategies are adopted. Examples are as follows:

[0086] After changing the installed capacity ratio, 12 The corresponding real part value is 795.62W.

[0087] Apply the network control strategy of networked units and Z 12 The corresponding real part value is 773.4W. Subtracting the above two values ​​from 763.85W, the difference corresponding to changing the installed capacity ratio is 31.77W, and the difference corresponding to applying the grid-type unit grid control strategy is 9.55W. It can be determined that "changing the installed capacity ratio" has a greater impact on improving the grid connection strength than "applying the grid-type unit grid control strategy".

[0088] The determining, according to the first comparison result, a difference evaluation result of the impact of the new energy grid connection strength improvement strategy on the new energy station impedance includes:

[0089] The first comparison results are sorted in descending order, and the difference evaluation result is determined according to the sorting order. Referring to the above example, the sorting order is 31.77W, 9.55W, so that the difference evaluation result can be determined more intuitively and conveniently.

[0090] After the step of determining the difference evaluation result of the impact of the new energy grid connection strength improvement strategy on the new energy station impedance according to the first comparison result, the difference evaluation method of the impact of the grid connection strength on the new energy station impedance also includes:

[0091] Another reference impedance real part value is selected to compare with the real part value of the impedance to be compared of the element at the corresponding position, and the difference evaluation result is verified according to the second comparison result. 12 The real part of the impedance is the same as Z. 21 The corresponding real part of the impedance is used to calculate Z 12 The same calculation process is performed for the real part of the impedance, thereby verifying the correctness of the above difference evaluation results.

[0092] The present invention aims to systematically evaluate the differences in the impact of different grid-connected strength improvement methods on the impedance characteristics of new energy stations under amplitude-frequency modulation oscillation conditions. It is important to emphasize the differences in the calculation of the impact on the sub-diagonal elements of the impedance matrix, thereby providing a scientific basis and technical support for practical engineering applications.

[0093] In order to evaluate the difference in the impact of different grid-connected strength improvement methods on the impedance of new energy stations under amplitude-frequency modulation oscillation, the present invention provides a method for converting the sub-diagonal impedance elements under amplitude-frequency modulation oscillation conditions according to the sub-diagonal impedance elements under sub- and super-synchronous oscillation conditions, and accurately measures the sub-diagonal impedance elements under amplitude-frequency modulation oscillation conditions, providing an effective solution for evaluating the difference in the impact of grid-connected strength on amplitude-frequency modulation oscillation types.

[0094] The embodiment of the present invention provides a method for evaluating the difference in the impact of grid connection strength on the impedance of a new energy station, which obtains the real part value of the reference impedance of the sub-diagonal elements under the historical amplitude-frequency oscillation voltage when the new energy grid connection strength improvement strategy is not adopted, and obtains the real part value of the impedance to be compared of the sub-diagonal elements under the historical amplitude-frequency oscillation voltage when at least one new energy grid connection strength improvement strategy is adopted; arbitrarily selects a reference impedance real part value and the real part value of the impedance to be compared of the element at the corresponding position for numerical comparison, and determines the difference evaluation result of the impact of the new energy grid connection strength improvement strategy on the impedance of the new energy station according to the first comparison result. By accurately calculating the relevant values ​​of the sub-diagonal elements of the impedance matrix, the difference evaluation of the impact of the grid connection strength on the impedance of the new energy station can be fully and accurately achieved.

[0095] Furthermore, the obtaining of the real part value of the reference impedance of the sub-diagonal element under the historical amplitude-frequency oscillation voltage when the new energy grid connection strength improvement strategy is not adopted includes:

[0096] Subsynchronous voltage excitation signals and supersynchronous voltage excitation signals are applied to the new energy grid connection points that do not adopt the new energy grid connection strength improvement strategy, and the amplitude and phase of the sub-diagonal elements of the reference impedance matrix are calculated; the above-mentioned embodiment can be referred to for description and will not be repeated here.

[0097] The real part value of the reference impedance is calculated based on the amplitude and phase of the sub-diagonal elements of the reference impedance matrix, and the pre-obtained reference first initial phase, reference second initial phase, reference third initial phase and reference fourth initial phase; please refer to the above embodiment for description and will not be repeated here.

[0098] The first reference initial phase corresponds to the reference voltage amplitude response signal, the second reference initial phase corresponds to the reference voltage frequency response signal, the third reference initial phase corresponds to the reference voltage amplitude measurement signal of the historical oscillation event, and the fourth reference initial phase corresponds to the reference voltage frequency measurement signal of the historical oscillation event. The above embodiments can be referred to for explanation and will not be described in detail.

[0099] Furthermore, the sub-synchronous voltage excitation signal and the super-synchronous voltage excitation signal are respectively applied to the new energy grid connection point that does not adopt the new energy grid connection strength improvement strategy, and the amplitude and phase of the sub-diagonal elements of the reference impedance matrix are calculated, including:

[0100] When applying the sub-synchronous voltage excitation signal, a reference first induced voltage and a reference first induced current related to the reference first diagonal element are obtained; the above-mentioned embodiment can be referred to for description and will not be described in detail.

[0101] According to the ratio of the reference first induced voltage and the reference first induced current, the amplitude and phase of the first diagonal element of the reference impedance matrix are determined; the above-mentioned embodiment can be referred to for description and will not be repeated here.

[0102] When the super-synchronous voltage excitation signal is applied, a reference second induced voltage and a reference second induced current related to the reference second diagonal element are obtained; the description may refer to the above embodiment and will not be repeated here.

[0103] According to the ratio of the reference second induced voltage to the reference second induced current, the amplitude and phase of the second diagonal element of the reference impedance matrix are determined. The above description can be made with reference to the above embodiment, which will not be repeated here.

[0104] Furthermore, the step of obtaining the real part value of the impedance to be compared of the sub-diagonal element under the historical amplitude-frequency oscillation voltage when adopting at least one new energy grid-connected strength improvement strategy includes:

[0105] Subsynchronous voltage excitation signals and supersynchronous voltage excitation signals are respectively applied to the new energy grid connection points that adopt at least one new energy grid connection strength improvement strategy, and the amplitude and phase of the sub-diagonal elements of the impedance matrix to be compared are calculated; the above-mentioned embodiments can be referred to for description and will not be repeated here.

[0106] The real part value of the impedance to be compared is calculated based on the amplitude and phase of the sub-diagonal elements of the impedance matrix to be compared, and the pre-obtained first initial phase to be compared, the second initial phase to be compared, the third initial phase to be compared, and the fourth initial phase to be compared; the description can be made with reference to the above embodiment and will not be repeated here.

[0107] The first initial phase to be compared corresponds to the voltage amplitude response signal to be compared, the second initial phase to be compared corresponds to the voltage frequency response signal to be compared, the third initial phase to be compared corresponds to the voltage amplitude measurement signal to be compared of the historical oscillation event, and the fourth initial phase to be compared corresponds to the voltage frequency measurement signal to be compared of the historical oscillation event. The above embodiments can be referred to for explanation and will not be repeated here.

[0108] Further, the sub-synchronous voltage excitation signal and the super-synchronous voltage excitation signal are respectively applied to the new energy grid connection point adopting at least one new energy grid connection strength improvement strategy, and the amplitude and phase of the sub-diagonal elements of the impedance matrix to be compared are calculated, including:

[0109] When applying the sub-synchronous voltage excitation signal, the first induced voltage to be compared and the first induced current to be compared related to the first diagonal element to be compared are obtained; the above-mentioned embodiment can be referred to for description and will not be repeated here.

[0110] According to the ratio of the first induced voltage to be compared and the first induced current to be compared, the amplitude and phase of the first diagonal element of the impedance matrix to be compared are determined; the above-mentioned embodiment can be referred to for description and will not be repeated here.

[0111] When the super-synchronous voltage excitation signal is applied, the second induced voltage to be compared and the second induced current to be compared related to the second diagonal element to be compared are obtained; the above-mentioned embodiment can be referred to for description and will not be repeated here.

[0112] According to the ratio of the second induced voltage to be compared and the second induced current to be compared, the amplitude and phase of the second diagonal element of the impedance matrix to be compared are determined. The above description can be made with reference to the above embodiment, which will not be repeated here.

[0113] Furthermore, the determining of the difference evaluation result of the impact of the new energy grid connection strength improvement strategy on the new energy station impedance according to the first comparison result includes:

[0114] The first comparison results are sorted in descending order, and the difference evaluation result is determined according to the sorting order. The above description can be referred to in the above embodiment, which will not be repeated here.

[0115] Further, after the step of determining the difference evaluation result of the impact of the new energy grid connection strength improvement strategy on the new energy station impedance according to the first comparison result, the difference evaluation method of the impact of the grid connection strength on the new energy station impedance also includes:

[0116] Another reference impedance real part value is selected to perform numerical comparison with the real part value of the impedance to be compared of the element at the corresponding position, and the difference evaluation result is verified according to the second comparison result. The above-mentioned embodiment can be referred to for explanation and will not be described in detail.

[0117] Figure 6 is a schematic diagram of a structure of a device for evaluating the difference in the impact of grid connection strength on impedance of a new energy station provided by an embodiment of the present invention. Figure 6 As shown, the difference evaluation device of the influence of grid connection strength on the impedance of new energy stations provided by the embodiment of the present invention includes an acquisition unit 601 and an evaluation unit 602, wherein:

[0118] The acquisition unit 601 is used to obtain the real part value of the reference impedance of the sub-diagonal elements under the historical amplitude-frequency oscillation voltage when the new energy grid-connected strength improvement strategy is not adopted, and to obtain the real part value of the impedance to be compared of the sub-diagonal elements under the historical amplitude-frequency oscillation voltage when at least one new energy grid-connected strength improvement strategy is adopted; the evaluation unit 602 is used to arbitrarily select a reference impedance real part value and the real part value of the impedance to be compared of the element at the corresponding position for numerical comparison, and determine the difference evaluation result of the impact of the new energy grid-connected strength improvement strategy on the impedance of the new energy station according to the first comparison result.

[0119] Specifically, the acquisition unit 601 in the device is used to obtain the real part value of the reference impedance of the sub-diagonal elements under the historical amplitude-frequency oscillation voltage when the new energy grid-connected strength improvement strategy is not adopted, and to obtain the real part value of the impedance to be compared of the sub-diagonal elements under the historical amplitude-frequency oscillation voltage when at least one new energy grid-connected strength improvement strategy is adopted; the evaluation unit 602 is used to arbitrarily select a reference impedance real part value and the real part value of the impedance to be compared of the element at the corresponding position for numerical comparison, and determine the difference evaluation result of the impact of the new energy grid-connected strength improvement strategy on the impedance of the new energy station according to the first comparison result.

[0120] The embodiment of the present invention provides a device for evaluating the difference in the impact of grid connection strength on the impedance of a new energy station, which obtains the real part value of the reference impedance of the sub-diagonal elements under the historical amplitude-frequency oscillation voltage when the new energy grid connection strength improvement strategy is not adopted, and obtains the real part value of the impedance to be compared of the sub-diagonal elements under the historical amplitude-frequency oscillation voltage when at least one new energy grid connection strength improvement strategy is adopted; arbitrarily selects a reference impedance real part value and the real part value of the impedance to be compared of the element at the corresponding position for numerical comparison, and determines the difference evaluation result of the impact of the new energy grid connection strength improvement strategy on the impedance of the new energy station according to the first comparison result. By accurately calculating the relevant values ​​of the sub-diagonal elements of the impedance matrix, the difference evaluation of the impact of the grid connection strength on the impedance of the new energy station can be fully and accurately achieved.

[0121] The embodiment of the present invention provides an embodiment of a device for evaluating the difference in the impact of grid-connected strength on the impedance of a new energy station, which can be specifically used to execute the processing flow of the above-mentioned method embodiments. Its functions are not repeated here, and reference can be made to the detailed description of the above-mentioned method embodiments.

[0122] Figure 7 A schematic diagram of the physical structure of an electronic device provided in an embodiment of the present invention, such as Figure 7 As shown, the electronic device includes: a processor (processor) 701, a memory (memory) 702 and a bus 703;

[0123] The processor 701 and the memory 702 communicate with each other via a bus 703;

[0124] The processor 701 is used to call the program instructions in the memory 702 to execute the methods provided by the above method embodiments, for example, including:

[0125] Obtaining the real part value of the reference impedance of the sub-diagonal element under the historical amplitude-frequency oscillation voltage when the strategy for improving the grid connection strength of new energy is not adopted, and obtaining the real part value of the impedance to be compared of the sub-diagonal element under the historical amplitude-frequency oscillation voltage when at least one strategy for improving the grid connection strength of new energy is adopted;

[0126] A real part value of a benchmark impedance is arbitrarily selected to be numerically compared with the real part value of the impedance to be compared of the element at the corresponding position, and a difference evaluation result of the impact of the new energy grid-connected intensity improvement strategy on the impedance of the new energy site is determined according to the first comparison result.

[0127] This embodiment discloses a computer program product, which includes a computer program stored on a non-transitory computer-readable storage medium. The computer program includes program instructions. When the program instructions are executed by a computer, the computer can perform the methods provided by the above method embodiments, for example, including:

[0128] Obtaining the real part value of the reference impedance of the sub-diagonal element under the historical amplitude-frequency oscillation voltage when the strategy for improving the grid connection strength of new energy is not adopted, and obtaining the real part value of the impedance to be compared of the sub-diagonal element under the historical amplitude-frequency oscillation voltage when at least one strategy for improving the grid connection strength of new energy is adopted;

[0129] A real part value of a benchmark impedance is arbitrarily selected to be numerically compared with the real part value of the impedance to be compared of the element at the corresponding position, and a difference evaluation result of the impact of the new energy grid-connected intensity improvement strategy on the impedance of the new energy site is determined according to the first comparison result.

[0130] This embodiment provides a computer-readable storage medium, wherein the computer-readable storage medium stores a computer program, wherein the computer program enables the computer to execute the methods provided by the above method embodiments, for example, including:

[0131] Obtaining the real part value of the reference impedance of the sub-diagonal element under the historical amplitude-frequency oscillation voltage when the strategy for improving the grid connection strength of new energy is not adopted, and obtaining the real part value of the impedance to be compared of the sub-diagonal element under the historical amplitude-frequency oscillation voltage when at least one strategy for improving the grid connection strength of new energy is adopted;

[0132] A real part value of a benchmark impedance is arbitrarily selected to be numerically compared with the real part value of the impedance to be compared of the element at the corresponding position, and a difference evaluation result of the impact of the new energy grid-connected intensity improvement strategy on the impedance of the new energy site is determined according to the first comparison result.

[0133] Those skilled in the art will appreciate that embodiments of the present invention may be provided as methods, systems, or computer program products. Therefore, the present invention may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0134] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0135] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0136] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0137] In the description of this specification, the description with reference to the terms "one embodiment", "a specific embodiment", "some embodiments", "for example", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0138] The specific embodiments described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for evaluating the difference in the impact of grid connection intensity on the impedance of new energy stations, characterized in that: include: Obtaining the real part value of the reference impedance of the sub-diagonal element under the historical amplitude-frequency oscillation voltage when the strategy for improving the grid connection strength of new energy is not adopted, and obtaining the real part value of the impedance to be compared of the sub-diagonal element under the historical amplitude-frequency oscillation voltage when at least one strategy for improving the grid connection strength of new energy is adopted; A real part value of a benchmark impedance is arbitrarily selected to be numerically compared with the real part value of the impedance to be compared of the element at the corresponding position, and a difference evaluation result of the impact of the new energy grid-connected intensity improvement strategy on the impedance of the new energy site is determined according to the first comparison result.

2. The method for evaluating the difference of the impact of grid connection strength on the impedance of new energy stations according to claim 1 is characterized in that: The obtaining of the real part value of the reference impedance of the sub-diagonal element under the historical amplitude-frequency oscillation voltage when the new energy grid connection strength improvement strategy is not adopted includes: Subsynchronous voltage excitation signals and supersynchronous voltage excitation signals are respectively applied to the new energy grid connection points that do not adopt the new energy grid connection strength improvement strategy, and the amplitude and phase of the sub-diagonal elements of the reference impedance matrix are calculated; Calculate the real part value of the reference impedance according to the amplitude and phase of the sub-diagonal elements of the reference impedance matrix, and the pre-obtained reference first initial phase, reference second initial phase, reference third initial phase and reference fourth initial phase; Among them, the reference first initial phase corresponds to the reference voltage amplitude response signal, the reference second initial phase corresponds to the reference voltage frequency response signal, the reference third initial phase corresponds to the reference voltage amplitude measurement signal of the historical oscillation event, and the reference fourth initial phase corresponds to the reference voltage frequency measurement signal of the historical oscillation event.

3. The method for evaluating the difference of the impact of grid connection strength on the impedance of new energy stations according to claim 2 is characterized in that: The sub-synchronous voltage excitation signal and the super-synchronous voltage excitation signal are respectively applied to the new energy grid connection point that does not adopt the new energy grid connection strength improvement strategy, and the amplitude and phase of the sub-diagonal elements of the reference impedance matrix are calculated, including: When applying the sub-synchronous voltage excitation signal, obtaining a reference first induced voltage and a reference first induced current associated with a reference first diagonal element; Determining the amplitude and phase of the first diagonal element of the reference impedance matrix according to the ratio of the reference first induced voltage to the reference first induced current; When applying the super-synchronous voltage excitation signal, obtaining a reference second induced voltage and a reference second induced current associated with the reference second diagonal element; The amplitude and phase of the second sub-diagonal elements of the reference impedance matrix are determined according to the ratio of the reference second induced voltage to the reference second induced current.

4. The method for evaluating the difference of the impact of grid connection strength on the impedance of new energy stations according to claim 1 is characterized in that: The step of obtaining the real part value of the impedance to be compared of the sub-diagonal element under the historical amplitude-frequency oscillation voltage when adopting at least one new energy grid-connected strength improvement strategy comprises: Applying a subsynchronous voltage excitation signal and a supersynchronous voltage excitation signal to a new energy grid connection point that adopts at least one new energy grid connection strength improvement strategy, respectively, and calculating the amplitude and phase of the sub-diagonal elements of the impedance matrix to be compared; Calculate the real part value of the impedance to be compared according to the amplitude and phase of the sub-diagonal elements of the impedance matrix to be compared, and the pre-obtained first initial phase to be compared, the second initial phase to be compared, the third initial phase to be compared, and the fourth initial phase to be compared; Among them, the first initial phase to be compared corresponds to the voltage amplitude response signal to be compared, the second initial phase to be compared corresponds to the voltage frequency response signal to be compared, the third initial phase to be compared corresponds to the voltage amplitude measurement signal to be compared of the historical oscillation event, and the fourth initial phase to be compared corresponds to the voltage frequency measurement signal to be compared of the historical oscillation event.

5. The method for evaluating the difference of the impact of grid connection strength on the impedance of new energy stations according to claim 4 is characterized in that: The sub-synchronous voltage excitation signal and the super-synchronous voltage excitation signal are respectively applied to the new energy grid connection point adopting at least one new energy grid connection strength improvement strategy, and the amplitude and phase of the sub-diagonal elements of the impedance matrix to be compared are calculated, including: When applying the sub-synchronous voltage excitation signal, obtaining a first induced voltage to be compared and a first induced current to be compared related to the first diagonal element to be compared; Determining the amplitude and phase of the first sub-diagonal element of the impedance matrix to be compared according to the ratio of the first induced voltage to be compared to the first induced current to be compared; When applying the super-synchronous voltage excitation signal, obtaining a second induced voltage to be compared and a second induced current to be compared related to the second diagonal element to be compared; The amplitude and phase of the second sub-diagonal element of the impedance matrix to be compared are determined according to the ratio of the second induced voltage to be compared to the second induced current to be compared.

6. The method for evaluating the difference of the impact of grid connection strength on the impedance of new energy stations according to claim 1 is characterized in that: The determining, according to the first comparison result, a difference evaluation result of the impact of the new energy grid connection strength improvement strategy on the new energy station impedance includes: The first comparison results are sorted in descending order, and the difference evaluation result is determined according to the sorting order.

7. The method for evaluating the difference in the impact of grid connection strength on the impedance of new energy stations according to any one of claims 1 to 6, characterized in that: After the step of determining the difference evaluation result of the impact of the new energy grid connection strength improvement strategy on the new energy station impedance according to the first comparison result, the difference evaluation method of the impact of the grid connection strength on the new energy station impedance also includes: Another reference impedance real part value is selected to perform numerical comparison with the real part value of the impedance to be compared of the element at the corresponding position, and the difference evaluation result is verified according to the second comparison result.

8. A device for evaluating the difference in the impact of grid connection strength on the impedance of a new energy station, characterized in that: include: An acquisition unit, used to acquire the real part value of the reference impedance of the sub-diagonal element under the historical amplitude-frequency oscillation voltage when the new energy grid-connected strength improvement strategy is not adopted, and to acquire the real part value of the impedance to be compared of the sub-diagonal element under the historical amplitude-frequency oscillation voltage when at least one new energy grid-connected strength improvement strategy is adopted; An evaluation unit is used to arbitrarily select a reference impedance real part value and compare it with the real part value of the impedance to be compared of the corresponding position element, and determine the difference evaluation result of the impact of the new energy grid-connected strength improvement strategy on the impedance of the new energy station according to the first comparison result.

9. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the computer program, the steps of the method according to any one of claims 1 to 7 are implemented.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 7 are implemented.

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