Fault voltage transient data evaluation method and device in grid-related test of photovoltaic power station

Abstract

The invention provides a fault voltage transient data evaluation method, device and equipment in a photovoltaic power station grid-related test and a medium, and the method comprises the steps: collecting fault ride-through test time sequence data of a static var generator, and determining a voltage difference value between adjacent sampling time points; each voltage difference value is compared with a preset voltage difference threshold value, a steady-state interval and a transient-state interval are determined according to a comparison result, when the voltage difference value of a time interval is larger than the preset voltage difference threshold value, the time interval is the transient-state interval, and otherwise, the time interval is the steady-state interval; and according to a preset evaluation index and an evaluation index standard value, determining an actual value corresponding to the evaluation index based on the determined steady state interval and transient state interval, and comparing the actual value of the evaluation index with the corresponding evaluation index standard value to obtain a test evaluation result. According to the method and the device, the time cost and the labor cost of the fault ride-through test in the network-related test are effectively saved, and the inaccuracy or the incredibility of the evaluation result caused by human participation is also avoided.

Description

Technical Field

[0001] The present invention relates to the technical field of transient data evaluation, and in particular to a method, device, equipment and medium for evaluating transient data of fault voltage in grid-related testing of a photovoltaic power station. Background Art

[0002] With the accelerated transformation and development of new power systems, the penetration rate of renewable energy generation is gradually increasing, and the safety and stability of the power grid are also facing great challenges, which puts forward certain requirements for photovoltaic stations. For example, after being connected to the grid, photovoltaic stations need to carry out a series of grid-related tests such as automatic generation control (AGC) / automatic voltage control (AVC) system testing, power quality testing, primary frequency regulation testing, static var generator (SVG) grid-connected performance testing, SVG single-machine fault ride-through testing, and grid-connected adaptability, and submit corresponding test reports.

[0003] In the prior art, SVG fault ride-through test mainly uses a fault signal generator connected to the test line to provide a fault signal, and uses the fault signal generator to collect various test data of the test line to evaluate indicators such as voltage drop depth and drop time. In the process of SVG fault ride-through test of photovoltaic power station, the data of fault ride-through involves various types, such as different voltage swell / drop depths. When evaluating the SVG fault ride-through performance, testers mainly rely on manual positioning, collection, and calculation, which requires a lot of time and manpower costs, especially when locating the fault voltage time point, which consumes more time and manpower costs, causing a great workload for testers.

[0004] In view of this, there is an urgent need to provide a method for distinguishing the steady-state interval and the transient interval in the test data and automatically realizing the evaluation of the transient data of the fault voltage. Summary of the invention

[0005] In order to overcome the problems existing in the related art, the present disclosure provides a method, device, equipment and medium for evaluating transient data of fault voltage in grid-related testing of a photovoltaic power station to solve the technical problems in the related art.

[0006] One or more embodiments of this specification provide a method for evaluating transient data of fault voltage in a photovoltaic power station grid-related test, characterized in that it includes the steps of:

[0007] Collect the time series data of the fault ride-through test of the static reactive generator, and determine the voltage difference between each adjacent sampling time point; compare each voltage difference with a preset voltage difference threshold, and determine the steady-state interval and the transient interval according to the comparison result, wherein when the voltage difference of a time interval is greater than the preset voltage difference threshold, it is a transient interval, otherwise it is a steady-state interval;

[0008] According to the preset evaluation index and the standard value of the evaluation index, based on the determined steady-state interval and transient interval, the actual value corresponding to the evaluation index is determined, and the actual value of the evaluation index is compared with the corresponding standard value of the evaluation index to obtain the test evaluation result.

[0009] Furthermore, the step of comparing each voltage difference with a preset voltage difference threshold and determining the steady-state interval and the transient interval according to the comparison result specifically includes the following steps:

[0010] Determine the voltage difference on both sides of each sampling time point one by one. If the voltage difference on both sides is not both greater than the voltage difference threshold or both less than the voltage difference threshold, the corresponding sampling time point is used as the interval demarcation point;

[0011] According to the interval demarcation point, when the voltage difference of the demarcation interval is greater than the preset voltage difference threshold, it is a transient interval, otherwise it is a steady-state interval.

[0012] Further, according to the voltage rise and fall, the transient interval includes a surge transient interval and a drop transient interval, and the steady-state interval includes a fault steady-state interval and a pre-fault steady-state interval;

[0013] The determination of the swell transient interval and the drop transient interval includes the following steps: if the voltage value corresponding to the termination demarcation point of the transient interval is greater than the voltage value corresponding to the termination demarcation point of the transient interval, it is a swell transient interval; if it is less than, it is a drop transient interval;

[0014] The determination of the fault steady-state interval and the non-fault steady-state interval includes the following steps: if the voltage average value corresponding to the steady-state interval is greater than the starting voltage value, it is a fault steady-state interval; if the voltage average value corresponding to the steady-state interval is approximately equal to the starting voltage value, it is a non-fault steady-state interval.

[0015] Furthermore, the evaluation index includes the voltage before the fault, the voltage during the fault, the drop / surge amplitude, the drop / surge time and / or the fault time.

[0016] One or more embodiments of this specification provide a device for evaluating transient data of fault voltage in a photovoltaic power station grid-related test, including:

[0017] A data acquisition module is used to acquire the static reactive generator fault ride-through test time series data and determine the voltage difference between each adjacent sampling time point;

[0018] A partitioning module is used to compare the voltage difference between each adjacent sampling time point with a preset voltage difference threshold, and determine the steady-state interval and the transient interval according to the comparison result, wherein when the voltage difference in a time interval is greater than the preset voltage difference threshold, it is a transient interval, otherwise it is a steady-state interval;

[0019] The evaluation module is used to determine the actual value corresponding to the evaluation indicator according to the preset evaluation indicator and the standard value of the evaluation indicator, based on the determined steady-state interval and transient interval, and compare the actual value of the evaluation indicator with the corresponding standard value of the evaluation indicator to obtain the test evaluation result.

[0020] Furthermore, the partition module is specifically configured to perform the following steps:

[0021] The voltage difference on both sides of each sampling time point is determined one by one. If the voltage difference on both sides is not both greater than the voltage difference threshold or both less than the voltage difference threshold, the corresponding sampling time point is used as the interval demarcation point.

[0022] According to the interval demarcation point, when the voltage difference of the demarcation interval is greater than the preset voltage difference threshold, it is a transient interval, otherwise it is a steady-state interval.

[0023] Further, according to the voltage rise and fall, the transient interval includes a sudden rise transient interval and a drop transient interval, and the steady state interval includes a fault steady state interval and a pre-fault steady state interval. The partition module is further configured to perform the following steps:

[0024] The step of judging the swell transient interval and the sag transient interval is as follows: if the voltage value corresponding to the termination demarcation point of the transient interval is greater than the voltage value corresponding to the termination demarcation point of the transient interval, it is a swell transient interval; if it is less than, it is a sag transient interval;

[0025] The steps for judging the fault steady-state interval and the non-fault steady-state interval are as follows: if the voltage average value corresponding to the steady-state interval is greater than the starting voltage value, it is a fault steady-state interval; if the voltage average value corresponding to the steady-state interval is approximately equal to the starting voltage value, it is a non-fault steady-state interval.

[0026] Furthermore, the evaluation index includes the voltage before the fault, the voltage during the fault, the drop / surge amplitude, the drop / surge time and / or the fault time.

[0027] One or more embodiments of the present specification provide a computer device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the computer program, a method for evaluating transient data of fault voltage in a grid-related test of a photovoltaic power station as described in any one of the above items is implemented.

[0028] One or more embodiments of the present specification provide a computer-readable storage medium storing a computer program, which, when executed by a processor, implements a method for evaluating transient data of fault voltage in a photovoltaic power station grid-related test as described in any one of the above items.

[0029] The present invention provides a method, device, equipment and medium for evaluating transient data of fault voltage in grid-related testing of photovoltaic power stations. The advantages are that key data collection is achieved by collecting SVG fault ride-through test data, the steady-state interval and transient interval are quickly located by using the change of voltage data, the actual value corresponding to the evaluation index is determined based on the steady-state interval and the transient interval, and whether the test data is qualified is identified by comparing the actual value corresponding to the evaluation index with the standard value. The whole process can be realized through a computer program. When determining the steady-state interval and the transient interval, the voltage difference between each adjacent sampling time point is compared with the voltage difference threshold, so as to quickly and accurately realize the interval positioning of the steady-state interval of the transient interval, effectively avoiding the influence of the small fluctuation of the steady-state interval that cannot be found by humans on the interval positioning result, not only effectively saving the time cost and labor cost of the fault ride-through test in the grid-related testing, but also avoiding the inaccuracy or unreliability of the evaluation result caused by human participation. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate one or more embodiments of this specification or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this specification. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0031] Figure 1 A flow chart of a method for evaluating fault voltage transient data in a photovoltaic power station grid-related test provided by one or more embodiments of this specification;

[0032] Figure 2 A timing diagram of a fault ride-through test of SVG collected for one or more embodiments of this specification;

[0033] Figure 3 A specific architecture diagram of a method for evaluating fault voltage transient data in a photovoltaic power station grid-related test provided by one or more embodiments of this specification;

[0034] Figure 4 A block diagram of a device for evaluating transient data of fault voltage in a photovoltaic power station grid-related test provided by one or more embodiments of this specification; and

[0035] Figure 5A schematic diagram of the structure of a computer device provided for one or more embodiments of this specification. DETAILED DESCRIPTION

[0036] In order to enable those skilled in the art to better understand the technical solutions in one or more embodiments of this specification, the technical solutions in one or more embodiments of this specification will be clearly and completely described below in conjunction with the drawings in one or more embodiments of this specification. Obviously, the described embodiments are only part of the embodiments of this specification, not all of the embodiments. Based on one or more embodiments of this specification, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0037] The present invention is described in detail below in conjunction with specific implementation methods and the accompanying drawings.

[0038] Method Embodiment

[0039] According to an embodiment of the present invention, a method for evaluating transient data of fault voltage in a photovoltaic power station grid-related test is provided. Figure 1 As shown, it is a flow chart of the method for evaluating transient data of fault voltage in the grid-related test of a photovoltaic power station provided in this embodiment. The method for evaluating transient data of fault voltage in the grid-related test of a photovoltaic power station according to an embodiment of the present invention includes:

[0040] Step S1, collecting static reactive power generator fault ride-through test time series data, and determining the voltage difference between each adjacent sampling time point;

[0041] Step S2, comparing the voltage difference between each adjacent sampling time point with the preset voltage difference threshold, and determining the steady-state interval and the transient interval according to the comparison result, wherein when the voltage difference in a time interval is greater than the preset voltage difference threshold, it is a transient interval, otherwise it is a steady-state interval.

[0042] Step S3, according to the preset evaluation index and the standard value of the evaluation index, based on the determined steady-state interval and transient interval, determine the actual value corresponding to the evaluation index, compare the actual value of the evaluation index with the corresponding standard value of the evaluation index, and obtain the test evaluation result.

[0043] The method for evaluating transient data of fault voltage in grid-related tests of photovoltaic power stations provided in this embodiment realizes key data collection by collecting SVG fault ride-through test data, quickly locates steady-state intervals and transient intervals by using changes in voltage data (i.e., voltage differences), determines actual values ​​corresponding to evaluation indicators based on steady-state intervals and transient intervals, and determines whether test data is qualified by comparing actual values ​​corresponding to evaluation indicators with standard values. The entire process can be realized through a computer program. When determining steady-state intervals and transient intervals, the voltage difference between adjacent sampling time points is compared with the voltage difference threshold, thereby quickly and accurately realizing interval positioning of the steady-state interval of the transient interval, effectively avoiding the influence of small fluctuations in the steady-state interval that cannot be discovered by humans on the interval positioning results, not only effectively saving the time cost and labor cost of fault ride-through tests in grid-related tests, but also avoiding inaccurate or unreliable evaluation results caused by human participation.

[0044] In this embodiment, the acquisition of the static reactive power generator fault ride-through test timing data mainly involves sequentially acquiring the voltage values ​​corresponding to each sampling time point during the SVG fault ride-through test in chronological order, storing the acquired voltage values ​​and their corresponding sampling time points, and then determining the voltage difference between each adjacent sampling time point, which is the voltage value corresponding to the next sampling time point minus the voltage value corresponding to the previous sampling time point adjacent to it; for example, each sampling time point is t1, t2, ..., tn, and corresponds to voltage values ​​U1, U2, ..., Un, respectively, then the voltage difference between each adjacent sampling time point is ΔU1, ΔU2, ..., ΔUn-1, respectively, wherein ΔU1 is the difference between U2 and U1, ΔU2 is the difference between U3 and U2, and so on, ΔUn-1 is the difference between Un and Un-1.

[0045] In one embodiment, comparing the voltage difference between each adjacent sampling time point with a preset voltage difference threshold, and determining the steady-state interval and the transient interval according to the comparison result specifically includes the following steps:

[0046] Step S21, determine the voltage difference on both sides of each sampling time point one by one, if the voltage difference on both sides is not both greater than the voltage difference threshold or both less than the voltage difference threshold, then use the corresponding sampling time point as the interval demarcation point.

[0047] refer to Figure 2 As shown in FIG. 1 , it is a timing diagram of the SVG fault ride-through test collected in this embodiment; Figure 2, assuming that ta, tb, tc, and td in the figure are sampling time points t1, t2, t3, and t4 respectively, this is an extreme case, t1, t2, t3, and t4 can actually be any continuous sampling time points on the time axis. In order to better illustrate the determination of the steady-state interval and the transient interval of this embodiment, it is assumed that ta, tb, tc, and td in the figure are sampling time points t1, t2, t3, and t4 respectively, then the corresponding voltage values ​​U1, U2, U3, and U4, the voltage difference between each adjacent sampling point They are ΔU1, ΔU2, and ΔU3 respectively. The voltage differences ΔU1 and ΔU2 on both sides of the sampling time point t2 (tb) do not satisfy that they are both greater than or both less than the voltage difference threshold ΔUm, the voltage differences ΔU2 and ΔU3 on both sides of the sampling time point t3 (tc) do not satisfy that they are both greater than or both less than the voltage difference threshold ΔUm, and the voltage differences ΔU3 and ΔU4 on both sides of the sampling time point t4 (td) do not satisfy that they are both greater than or both less than the voltage difference threshold ΔUm. Therefore, the sampling time points t2, t3, and t4 are all interval dividing points.

[0048] For example, assuming that at time point te between time points tb and tc, the voltage difference on both sides of the time point te satisfies the voltage difference threshold value ΔUm, so the time point te is not the interval demarcation point. This embodiment determines the interval demarcation point by determining whether the voltage difference on both sides of each sampling time point is greater than or less than the voltage difference threshold value, and can quickly and accurately locate the interval demarcation point.

[0049] Step S22: According to the interval demarcation point, when the voltage difference of the demarcation interval is greater than the preset voltage difference threshold, it is a transient interval, otherwise it is a steady-state interval.

[0050] The voltage in the steady-state interval usually tends to be stable, and the voltage difference between adjacent interval dividing points is small. However, due to the existence of voltage jumps in the transient interval, the voltage difference between adjacent interval dividing points will become larger. Therefore, the steady-state interval and the transient interval are determined according to the interval dividing points, including: traversing the dividing points of two adjacent intervals, calculating the voltage difference between the dividing points of two adjacent intervals, if it is less than the voltage difference threshold, then the voltage interval between the dividing points of the two adjacent intervals is regarded as the steady-state interval; if it is greater than the voltage difference threshold, then the voltage interval between the dividing points of the two adjacent intervals is regarded as the transient interval.

[0051] Furthermore, in order to determine the actual values ​​corresponding to the evaluation indicators in subsequent steps, the transient interval is divided into a sudden rise transient interval and a drop transient interval according to the rise and fall of the voltage, and the steady-state interval includes a fault steady-state interval and a pre-fault steady-state interval.

[0052] The determination of the swell transient interval and the drop transient interval includes the following steps: if the voltage value corresponding to the termination demarcation point of the transient interval is greater than the voltage value corresponding to the termination demarcation point of the transient interval, it is a swell transient interval; if it is less than, it is a drop transient interval;

[0053] The determination of the fault steady-state interval and the non-fault steady-state interval includes the following steps: if the voltage average value corresponding to the steady-state interval is greater than the starting voltage value, it is a fault steady-state interval; if the voltage average value corresponding to the steady-state interval is approximately equal to the starting voltage value, it is a non-fault steady-state interval.

[0054] Continue to refer Figure 2 Between the interval boundary points ta and tb, the voltage difference is greater than the voltage difference threshold ΔUm, so it is a transient interval. Between the interval boundary points tb and tc, the voltage difference is less than the voltage difference threshold ΔUm, so it is a steady-state interval.

[0055] In this embodiment, in order to prevent the positioning error of the demarcation point caused by the small voltage change in the steady-state interval, the voltage difference threshold is used to distinguish the steady-state interval from the transient interval, and the voltage difference threshold value can be 0.01pu. Of course, this embodiment does not limit the specific value of the voltage difference threshold, and those skilled in the art can set it according to actual needs, as long as it can meet the accuracy requirements for distinguishing the steady-state interval and the transient interval.

[0056] In this embodiment, step S3 calculates the actual value corresponding to each evaluation index based on the steady-state interval and transient interval and voltage change determined in step S2, thereby evaluating the high and low voltage ride-through capability of SVG on the test data according to the standard value corresponding to each evaluation index.

[0057] In this embodiment, the evaluation index is an index that can be used to evaluate the high and low voltage ride-through capability of the SVG, and may include but is not limited to the pre-fault voltage, the voltage during the fault, the drop / swell amplitude, the drop / swell time, the fault time and other indicators.

[0058] In one embodiment, when the evaluation index is the voltage value before the fault and the voltage value during the fault, the actual value corresponding to the evaluation index is determined as follows:

[0059] Based on the determined steady-state interval and transient interval, the voltage value corresponding to the starting sampling time point of the first transient interval arranged in chronological order is the starting voltage, that is, the actual value of the voltage before the fault, and the voltage value at the middle moment corresponding to the fault steady-state interval between the surge transient interval and the drop transient interval is the actual value of the voltage during the fault.

[0060] refer to Figure 2As shown, the non-fault steady-state interval A, the sudden swell transient interval A, the fault steady-state interval B, the drop transient interval B, and the non-fault steady-state interval C are arranged in chronological order, wherein the voltage difference ΔU of the non-fault steady-state interval A, the fault steady-state interval B, and the non-fault steady-state interval C are all less than the voltage difference threshold ΔUm, the voltage difference ΔU of the sudden swell transient interval A and the drop transient interval B are all greater than the voltage difference threshold ΔUm, the interval demarcation point between the non-fault steady-state interval A and the sudden swell transient interval A is the sampling time point ta, the sudden swell transient interval The interval demarcation point between the fault steady-state interval A and the fault steady-state interval B is the sampling time point tb, the interval demarcation point between the fault steady-state interval B and the drop transient interval B is the sampling time point tc, and the interval demarcation point between the drop transient interval B and the non-fault steady-state interval C is the sampling time point td. Assuming that the voltage values ​​corresponding to the interval demarcation points ta, tb, tc, and td are Ua, Ub, Uc, and Ud, respectively, then the voltage value Ua corresponding to the starting sampling time ta of the first transient interval, i.e., the non-fault steady-state interval A, is the actual value of the voltage before the fault. The middle moment of the fault steady-state interval B between the swell transient interval A and the drop transient interval B arranged in time order is recorded as te, and the voltage value Ue corresponding to the middle moment te is the actual value of the voltage during the fault, wherein the middle moment te = (tb+tc) / 2.

[0061] In another embodiment, when the evaluation index is the sudden increase amplitude, the actual value corresponding to the sudden increase amplitude is the ratio of the actual voltage value at the middle moment corresponding to the fault steady-state interval to the actual value of the initial / pre-fault voltage.

[0062] refer to Figure 2 As shown, when the actual value of the voltage during the fault is Ue and the actual value of the voltage before the fault is Ua, the actual value of the surge amplitude is Ue / Ua.

[0063] In one embodiment, when the evaluation index includes the surge time or the drop time, the actual value of the surge time is the time difference between the end demarcation point and the start demarcation point corresponding to the surge transient interval, which is used as the actual value of the surge time; the actual value of the drop time is the time difference between the end demarcation point and the start demarcation point corresponding to the drop transient interval.

[0064] refer to Figure 2 As shown, the difference Δta between the end sampling time point tb and the start sampling time point ta of the sudden rise transient interval A is the actual value of the sudden rise time, Δta=tb-ta.

[0065] In one embodiment, when the evaluation index includes fault time, the fault time is determined as follows: the time difference between the end dividing point of the drop transient interval arranged in chronological order and the interval dividing point of the surge transient interval before the time axis is taken as the actual value of the fault time.

[0066] refer to Figure 2 , the interval demarcation point time point of the sudden rise transient interval A is ta, and the termination sampling time point of the drop transient interval B is td, then the actual value of the fault time Δtb is Δtb=td-ta.

[0067] Compared with the prior art, the method for evaluating transient data of fault voltage in grid-related tests of photovoltaic power stations provided in this embodiment realizes key data collection by collecting SVG fault-crossing test data, and uses the rate of change of voltage data, that is, the voltage difference between adjacent sampling time points, to quickly locate the steady-state interval and transient interval, and determines the actual value corresponding to the evaluation index based on the steady-state interval and transient interval. By comparing the actual value corresponding to the evaluation index with the standard value, it automatically determines whether the test data is qualified, which effectively saves the time and labor costs of fault-crossing tests in grid-related tests. When determining the steady-state interval and transient interval, by comparing the voltage difference between adjacent sampling time points with the voltage difference threshold, it also effectively avoids the influence of small fluctuations in the steady-state interval on the interval positioning results.

[0068] To more clearly understand the implementation process of the above embodiment, according to Figure 2-Figure 3 The following is a specific example to illustrate the specific process steps of the fault voltage transient data evaluation method in the photovoltaic power station grid-related test.

[0069] (1) Based on the collected static reactive generator fault ride-through test time series data, the voltage test data change is calculated:

[0070] (1-1) Collect SVG fault ride-through test data and obtain the voltage values ​​U corresponding to each sampling time point t1, t2, ..., tn 1 , U 2 ,……,U n , store each sampling time point and its corresponding voltage value.

[0071] (1-2) Determine the voltage time series change rate: Calculate the voltage difference ΔU between each adjacent sampling time point 1 , ΔU 2 ,……,ΔU n-1 , where ΔU 1 For U 2 with U 1 The difference, ΔU 2 For U 3 with U 2 The difference between n-1 For U n with U n-1 The difference.

[0072] (2) Data judgment, determination of the starting and ending voltages and time of the transient interval:

[0073] (2-1) The voltage difference threshold ΔUm is set to 0.01pu to prevent the interval boundary point positioning error caused by small voltage changes in the steady-state interval.

[0074] (2-2) Determine the relationship between the voltage difference and the voltage difference threshold value between each adjacent sampling time point one by one in chronological order, determine the first voltage difference ΔU that satisfies ΔU>ΔUm, that is, the first voltage difference that is greater than the voltage difference threshold ΔUm, and record the starting sampling time point ta of the first voltage difference and its corresponding voltage value Ua.

[0075] (2-3) Determine the first voltage difference value ΔU that satisfies ΔU<ΔUm after the sampling time point ta, that is, the first voltage difference value that is less than the voltage difference threshold, and record the starting sampling time point tb of the first voltage difference value and its corresponding voltage value Ub.

[0076] (2-4) Determine the first voltage difference value ΔU that satisfies ΔU>ΔUm after the sampling time point tb, i.e., the first voltage difference value that is greater than the voltage difference threshold, and record the starting sampling time point tc of the first voltage difference value and its corresponding voltage value Uc.

[0077] (2-5) Determine the first voltage difference ΔU that satisfies ΔU<ΔUm after the sampling time point tc, that is, the first voltage difference that is less than the voltage difference threshold, and record the starting sampling time point td of the first voltage difference and its corresponding voltage value Ud. Thus, according to the time sequence and voltage change, the waveform is divided into a non-fault steady-state interval A, a sudden rise transient interval A, a fault steady-state interval B, a drop transient interval B, and a non-fault steady-state interval C, wherein the sampling time point ta is the interval demarcation point between the non-fault steady-state interval A and the sudden rise transient interval A, the sampling time point tb is the interval demarcation point between the sudden rise transient interval A and the fault steady-state interval B, the sampling time point tc is the interval demarcation point between the fault steady-state interval B and the drop transient interval B, and the sampling time point td is the interval demarcation point between the drop transient interval B and the non-fault steady-state interval.

[0078] (2-6) Determine the middle time te=(tb+tc) / 2 corresponding to the fault steady-state interval between the sudden rise transient interval A and the drop transient interval B, and collect the voltage value Ue corresponding to the sampling time point te.

[0079] (3) Calculate the actual value of the evaluation index:

[0080] (3-1) Evaluation index The actual value of the voltage before the fault is Ua.

[0081] (3-2) Evaluation index The actual value of the voltage during the fault is Ue.

[0082] (3-3) The actual value of the sudden increase in the evaluation index is Ue / Ua.

[0083] (3-4) The actual value of the evaluation index drop / surge time is Δta1=td-tc / Δta2=tb-ta.

[0084] (3-5) The actual value of the evaluation indicator failure time is Δtb=td-ta.

[0085] (3-6) Standard evaluation: Compare the actual value of each evaluation indicator with the corresponding standard value to obtain the evaluation result, which is the standard evaluation result.

[0086] Device Embodiment

[0087] According to an embodiment of the present invention, a device for evaluating transient data of fault voltage in a photovoltaic power station grid-related test is provided. Figure 4 As shown, it is a block diagram of a device for evaluating transient data of fault voltage in a photovoltaic power station grid-related test provided by this embodiment. The device for evaluating transient data of fault voltage in a photovoltaic power station grid-related test according to an embodiment of the present invention comprises:

[0088] The data acquisition module 10 is used to acquire the static reactive generator fault ride-through test time series data and determine the voltage difference between each adjacent sampling time point;

[0089] The partition module 20 is used to compare the voltage difference between each adjacent sampling time point with a preset voltage difference threshold, and determine the steady-state interval and the transient interval according to the comparison result, wherein when the voltage difference in a time interval is greater than the preset voltage difference threshold, it is a transient interval, otherwise it is a steady-state interval.

[0090] The evaluation module 30 is used to determine the actual value corresponding to the evaluation indicator according to the preset evaluation indicator and the evaluation indicator standard value, based on the determined steady-state interval and transient interval, and compare the actual value of the evaluation indicator with the corresponding evaluation indicator standard value to obtain the test evaluation result.

[0091] The present embodiment provides a device for evaluating transient data of fault voltage in grid-related tests of photovoltaic power stations. The partition module 20 collects key data by collecting SVG fault ride-through test data, and uses the change of voltage data (i.e., voltage difference) to quickly locate the steady-state interval and transient interval. The evaluation module 30 then determines the actual value corresponding to the evaluation index based on the steady-state interval and the transient interval, and compares the actual value corresponding to the evaluation index with the standard value to determine whether the test data is qualified. The entire process can be implemented through a computer program. When determining the steady-state interval and the transient interval, the voltage difference between each adjacent sampling time point is compared with the voltage difference threshold, so as to quickly and accurately realize the interval positioning of the steady-state interval of the transient interval, effectively avoiding the influence of the small fluctuation of the steady-state interval that cannot be found by humans on the interval positioning result, which not only effectively saves the time cost and labor cost of the fault ride-through test in the grid-related test, but also avoids the inaccuracy or unreliability of the evaluation result caused by human participation.

[0092] In this embodiment, the partition module 20 is specifically configured to perform the following steps:

[0093] Step S21, determine the voltage difference on both sides of each sampling time point one by one, if the voltage difference on both sides is not both greater than the voltage difference threshold or both less than the voltage difference threshold, then use the corresponding sampling time point as the interval demarcation point.

[0094] Step S22: According to the interval demarcation point, when the voltage difference of the demarcation interval is greater than the preset voltage difference threshold, it is a transient interval, otherwise it is a steady-state interval.

[0095] In this embodiment, the steady-state interval and the transient interval are determined according to the interval dividing points: traverse the two adjacent interval dividing points, calculate the voltage difference between the two adjacent interval dividing points, if it is less than the voltage difference threshold, then the voltage interval between the two adjacent interval dividing points is taken as the steady-state interval; if it is greater than the voltage difference threshold, then the voltage interval between the two adjacent interval dividing points is taken as the transient interval.

[0096] Further, in order for the subsequent evaluation module 30 to better determine the actual value corresponding to the evaluation index, the corresponding transient interval is divided into a sudden rise transient interval and a drop transient interval according to the rise and fall of the voltage, and the steady state interval includes a fault steady state interval and a pre-fault steady state interval, so the partition module 20 is further configured to perform the following steps:

[0097] The determination of the swell transient interval and the drop transient interval includes the following steps: if the voltage value corresponding to the termination demarcation point of the transient interval is greater than the voltage value corresponding to the termination demarcation point of the transient interval, it is a swell transient interval; if it is less than, it is a drop transient interval;

[0098] The determination of the fault steady-state interval and the non-fault steady-state interval includes the following steps: if the voltage average value corresponding to the steady-state interval is greater than the starting voltage value, it is a fault steady-state interval; if the voltage average value corresponding to the steady-state interval is approximately equal to the starting voltage value, it is a non-fault steady-state interval.

[0099] In this embodiment, in order to prevent the demarcation point positioning error caused by a small voltage change in the steady-state interval, a voltage difference threshold is used to distinguish the steady-state interval from the transient interval, and the voltage difference threshold value may be 0.01 pu.

[0100] In this embodiment, the evaluation index is an index that can be used to evaluate the high and low voltage ride-through capability of the SVG, and may include but is not limited to the pre-fault voltage, the voltage during the fault, the drop / swell amplitude, the drop / swell time, the fault time and other indicators.

[0101] The embodiment of the present invention is an apparatus embodiment corresponding to the above-mentioned method embodiment. The specific operations of the processing steps of each module can be understood by referring to the description of the method embodiment, which will not be repeated here.

[0102] like Figure 5 As shown, the present invention also provides a computer device, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the method for evaluating transient data of fault voltage in the grid-related test of a photovoltaic power station in the above-mentioned embodiment is implemented.

[0103] The present invention also provides a computer-readable storage medium having a computer program stored thereon. When the computer program is executed by a processor, the method for evaluating transient data of fault voltage in a photovoltaic power station grid-related test in the above-mentioned embodiment is implemented; or when the computer program is executed by a processor, the method for evaluating transient data of fault voltage in a photovoltaic power station grid-related test in the above-mentioned embodiment is implemented.

[0104] Those skilled in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be completed by instructing the relevant hardware through a computer program, and the computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to memory, storage, database or other media used in the embodiments provided in this application can include non-volatile and / or volatile memory. Non-volatile memory can include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM) or flash memory. Volatile memory can include random access memory (RAM) or external cache memory. As an illustration and not limitation, RAM is available in many forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous link (Synchlink) DRAM (SLDRAM), memory bus (Rambus) direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM).

[0105] Each embodiment in this specification is described in a progressive manner, and the same or similar parts between the embodiments can be referred to each other, and each embodiment focuses on the differences from other embodiments. In particular, for the device or system embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and the relevant parts can be referred to the partial description of the method embodiment. The device and system embodiments described above are merely schematic, wherein the units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place, or they may be distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the scheme of this embodiment. Ordinary technicians in this field can understand and implement it without paying creative labor.

[0106] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein by equivalents. These modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention, and the contents not described in detail in the specification of the present invention belong to the common knowledge of those skilled in the art.

Claims

1. A method for evaluating transient data of fault voltage in grid-related testing of photovoltaic power stations, characterized in that: Includes steps: Collect the time series data of the fault ride-through test of the static reactive generator, and determine the voltage difference between each adjacent sampling time point; compare each voltage difference with a preset voltage difference threshold, and determine the steady-state interval and the transient interval according to the comparison result, wherein when the voltage difference of a time interval is greater than the preset voltage difference threshold, it is a transient interval, otherwise it is a steady-state interval; According to the preset evaluation index and the standard value of the evaluation index, based on the determined steady-state interval and transient interval, the actual value corresponding to the evaluation index is determined, and the actual value of the evaluation index is compared with the corresponding standard value of the evaluation index to obtain the test evaluation result.

2. The method for evaluating transient data of fault voltage in grid-related testing of photovoltaic power station according to claim 1, characterized in that: The step of comparing each voltage difference with a preset voltage difference threshold and determining a steady-state interval and a transient interval according to the comparison result specifically includes the following steps: Determine the voltage difference on both sides of each sampling time point one by one. If the voltage difference on both sides is not both greater than the voltage difference threshold or both less than the voltage difference threshold, the corresponding sampling time point is used as the interval demarcation point; According to the interval demarcation point, when the voltage difference of the demarcation interval is greater than the preset voltage difference threshold, it is a transient interval, otherwise it is a steady-state interval.

3. The method for evaluating transient data of fault voltage in grid-related testing of photovoltaic power station according to claim 1, characterized in that: According to the voltage rise and fall, the transient interval includes a surge transient interval and a drop transient interval, and the steady-state interval includes a fault steady-state interval and a pre-fault steady-state interval; The determination of the swell transient interval and the drop transient interval includes the following steps: if the voltage value corresponding to the termination demarcation point of the transient interval is greater than the voltage value corresponding to the termination demarcation point of the transient interval, it is a swell transient interval; if it is less than, it is a drop transient interval; The determination of the fault steady-state interval and the non-fault steady-state interval includes the following steps: if the voltage average value corresponding to the steady-state interval is greater than the starting voltage value, it is a fault steady-state interval; if the voltage average value corresponding to the steady-state interval is equal to the starting voltage value, it is a non-fault steady-state interval.

4. The method for evaluating transient data of fault voltage in a photovoltaic power station grid-related test according to any one of claims 1 to 3, characterized in that: The evaluation indexes include the voltage before the fault, the voltage during the fault, the drop / surge amplitude, the drop / surge time and / or the fault time.

5. A device for evaluating transient data of fault voltage in grid-related testing of photovoltaic power stations, characterized in that: include: A data acquisition module is used to acquire the static reactive generator fault ride-through test time series data and determine the voltage difference between each adjacent sampling time point; A partitioning module is used to compare the voltage difference between each adjacent sampling time point with a preset voltage difference threshold, and determine the steady-state interval and the transient interval according to the comparison result, wherein when the voltage difference in a time interval is greater than the preset voltage difference threshold, it is a transient interval, otherwise it is a steady-state interval; The evaluation module is used to determine the actual value corresponding to the evaluation indicator according to the preset evaluation indicator and the standard value of the evaluation indicator, based on the determined steady-state interval and transient interval, and compare the actual value of the evaluation indicator with the corresponding standard value of the evaluation indicator to obtain the test evaluation result.

6. The device for evaluating transient data of fault voltage in grid-related testing of photovoltaic power station according to claim 5, characterized in that: The partition module is specifically configured to perform the following steps: Determine the voltage difference on both sides of each sampling time point one by one. If the voltage difference on both sides is not both greater than the voltage difference threshold or both less than the voltage difference threshold, the corresponding sampling time point is used as the interval demarcation point; According to the interval demarcation point, when the voltage difference of the demarcation interval is greater than the preset voltage difference threshold, it is a transient interval, otherwise it is a steady-state interval.

7. The device for evaluating transient data of fault voltage in grid-related testing of photovoltaic power station according to claim 5, characterized in that: According to the voltage rise and fall, the transient interval includes a sudden rise transient interval and a drop transient interval, and the steady state interval includes a fault steady state interval and a pre-fault steady state interval. The partition module is also specifically configured to perform the following steps: The step of judging the swell transient interval and the sag transient interval is as follows: if the voltage value corresponding to the termination demarcation point of the transient interval is greater than the voltage value corresponding to the termination demarcation point of the transient interval, it is a swell transient interval; if it is less than, it is a sag transient interval; The judgment steps of the fault steady-state interval and the non-fault steady-state interval are as follows: if the voltage average value corresponding to the steady-state interval is greater than the starting voltage value, it is a fault steady-state interval; if the voltage average value corresponding to the steady-state interval is equal to the starting voltage value, it is a non-fault steady-state interval.

8. The device for evaluating transient data of fault voltage in grid-related testing of a photovoltaic power station according to any one of claims 5 to 7, characterized in that: The evaluation indexes include the voltage before the fault, the voltage during the fault, the drop / surge amplitude, the drop / surge time and / or the fault time.

9. A computer 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 method for evaluating fault voltage transient data in a photovoltaic power station grid-related test according to any one of claims 1 to 4 is implemented.

10. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by a processor, the method for evaluating transient data of fault voltage in a photovoltaic power station grid-related test according to any one of claims 1 to 4 is implemented.

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