Grid connection performance evaluation method and system of power station

Abstract

The invention discloses a grid-connected performance evaluation method and system of a power station, and relates to the technical field of power grid performance evaluation, and the method comprises the steps: collecting grid-connected performance key parameters of the power station; and testing each key parameter to complete evaluation of the grid-connected performance of the power station. The system comprises an active power control performance test module, a reactive power control performance test module, an energy storage power station charging and discharging response time test module, an energy storage power station charging and discharging adjustment time test module, an energy storage power station charging and discharging conversion time test module and an energy storage power station overload capacity test module. The system comprises an energy storage power station rated power energy conversion efficiency test module, an electric energy quality test module and an energy storage power station primary frequency modulation test module. According to the invention, a plurality of parameter angles are tested by searching a more accurate starting or ending transition point, so that more accurate data reference is provided for power station grid connection, and the safety and the stability are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of power grid performance evaluation, and in particular to a method and system for evaluating the grid-connected performance of a power station. Background Art

[0002] There is a huge demand for grid connection of new energy projects every year. In order to ensure the safety and stability of the grid and the orderly supply of electricity, all power grid companies have taken effective measures to ensure timely grid connection for wind power and photovoltaic power generation projects that meet the conditions for grid connection. The traditional manual evaluation method has the following problems: 1. The amount of calculation data involved in the performance evaluation of new energy grid-related performance is huge, the manual calculation process is slow and the probability of error is high, the evaluation efficiency is low and the audit is difficult. 2. The quality of the performance evaluation results of new energy grid-related performance is not high and the objectivity is poor; and the accuracy of the grid performance data evaluation is low, which has an adverse impact on the safety and stability of the grid. Summary of the invention

[0003] The present invention aims at solving the problems in the prior art and provides a method and system for evaluating the grid-connected performance of a power station.

[0004] To achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0005] A method for evaluating the grid-connected performance of a power station comprises the following steps: step 1, collecting key parameters of the grid-connected performance of the power station, wherein the power station comprises an energy storage power station, a photovoltaic power station and a wind power station, the key parameters of the energy storage power station at least include active power, reactive power, power factor, charge and discharge response time, charge and discharge adjustment time, charge and discharge conversion time, overload capacity, rated energy, rated power energy conversion efficiency, power quality, high voltage ride-through, and low voltage ride-through; the key parameters of the photovoltaic power station and the wind power station at least include active power, high voltage ride-through, and low voltage ride-through; step 2, testing each key parameter; comparing the test result with a pre-set qualified condition; judging the performance by comparing the result, and then completing the evaluation of the grid-connected performance of the power station.

[0006] Based on the above technical solution, the test process of active power is further as follows: find the starting transition point and the ending transition point; calculate the response time and the adjustment time; calculate the measured average value and control the accuracy; among them, find the first point beyond the transition range and record its subscript i, use the subscript to reverse recursion, when the active power P corresponding to the current subscript i i The value minus the active power P corresponding to the next subscript i+1 value, where i is 1, 2, 3, etc.; the target value is set to N×P N , where N takes a negative value when in the charging state and a positive value when in the discharging state. When N takes a negative value, the active power P corresponding to the current index i i The value minus the active power P corresponding to the previous subscripti-1 When the difference between the values ​​is less than or equal to 0, the current active power P i The value is used as the value corresponding to the starting transition point. Find the target value ±P N The first point of the 2% floating range is the entry point. If the target value is negative, the entry point is used as the starting point to determine that when the current value minus the next value is less than or equal to 0, the data corresponding to the current value is the data of the end transition point. If the current value is positive, when the current value minus the next value is greater than or equal to 0, the current point is the end transition point.

[0007] Based on the above technical solution, further, the process of testing the reactive power regulation capability is: finding the starting transition point and generating a table.

[0008] Based on the above technical solution, further, the test process of the charge and discharge response time is: find the starting transition point, when the data transition reaches P for the first time N When the value is 90% of the value, record the time and subtract the time point when the data transition starts. The resulting time is the response time.

[0009] Based on the above technical solution, further, the test process of the charge and discharge adjustment time is: find the starting transition point; when the data transition reaches the target value and the second column active power deviation is controlled within P N ±P N The first point within 2% of the value of the ADC; record the time and subtract the start time of the data transition.

[0010] Based on the above technical solution, further, the test process of the charge-discharge conversion time is: find the charge state is less than or equal to P N × 90% and the discharge state is greater than or equal to P N ×90% of the position and record it; the difference between the later recorded time and the earlier recorded time is the conversion time.

[0011] Based on the above technical solution, further, the overload capacity test process is as follows: ±1 times P N Find the end point of the transition to the target value and the start point of the transition away from the target value, and calculate the time difference and average value between the two points; whether to transition depends on whether it exceeds P N 2% range; target value is N×P N .

[0012] Based on the above technical solution, further, the test of power quality includes statistics of harmonic voltage at the grid connection point, statistics of harmonic voltage between grid connection points, statistics of harmonic current at the grid connection point, test of three-phase voltage imbalance, test of bus flicker, test of DC component and test of simulated actual frequency disturbance.

[0013] Based on the above technical solution, further, the tests in photovoltaic and wind power stations include active power change maximum measurement value and active power control capability test, high voltage and low voltage test.

[0014] A grid-connected performance evaluation system for a power station comprises an active power control performance test module, a reactive power control performance test module, an energy storage power station charge and discharge response time test module, an energy storage power station charge and discharge adjustment time test module, an energy storage power station charge and discharge conversion time test module, an energy storage power station overload capacity test module, an energy storage power station rated power energy conversion efficiency test module, a power quality test module, and an energy storage power station primary frequency regulation test module.

[0015] Compared with the prior art, the present invention has the following beneficial effects:

[0016] The present invention can achieve the technical effect of improving the accuracy of power grid performance evaluation by finding more accurate starting or ending transition points to test multiple parameter angles, and making judgments and analyses based on the test results and the set qualified conditions that meet the standards, thereby providing more accurate data reference for power station grid connection and improving safety and stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 is a flow chart of the method of the present invention;

[0018] Figure 2 It is the active power rise curve diagram of the present invention;

[0019] Figure 3 It is the active power reduction curve diagram of the present invention;

[0020] Figure 4 It is the active power and reactive power envelope diagram of the present invention;

[0021] Figure 5 This is a schematic diagram of the first charging response time of the present invention;

[0022] Figure 6 This is a schematic diagram of the second charging response time of the present invention;

[0023] Figure 7 This is a schematic diagram of the third charging response time of the present invention;

[0024] Figure 8 This is a schematic diagram of the first discharge response time of the present invention;

[0025] Fig. 9 This is a schematic diagram of the second discharge response time of the present invention;

[0026] Fig.10 This is a schematic diagram of the third discharge response time of the present invention;

[0027] Fig.11 This is a schematic diagram of the first charging adjustment time of the present invention;

[0028] Fig.12 This is a schematic diagram of the second charging adjustment time of the present invention;

[0029] Fig.13 This is a schematic diagram of the third charging adjustment time of the present invention;

[0030] Fig.14 This is a schematic diagram of the first discharge adjustment time of the present invention;

[0031] Fig.15 This is a schematic diagram of the second discharge adjustment time of the present invention;

[0032] Fig.16 This is a schematic diagram of the third discharge adjustment time of the present invention;

[0033] Fig.17 This is a schematic diagram of the first charge to discharge conversion time of the present invention;

[0034] Fig.18 This is a schematic diagram of the second charge to discharge conversion time of the present invention;

[0035] Fig.19 This is a schematic diagram of the third charge-to-discharge conversion time of the present invention;

[0036] Fig. 20 This is a schematic diagram of the first discharge to charge conversion time of the present invention;

[0037] Fig.21 This is a schematic diagram of the second discharge to charge conversion time of the present invention;

[0038] Fig. 22 This is a schematic diagram of the third discharge to charge conversion time of the present invention;

[0039] Fig.23 The charging state of the present invention is 1.1P N Schematic diagram of overload capacity test;

[0040] Fig.24 The charging state of the present invention is 1.2P N Schematic diagram of overload capacity test;

[0041] Fig.25 The discharge state of the present invention is 1.1P N Schematic diagram of overload capacity test;

[0042] Fig.26 The discharge state of the present invention is 1.2P N Schematic diagram of overload capacity test;

[0043] Fig. 27Schematic diagram of simulating actual frequency disturbance in the test of the present invention. DETAILED DESCRIPTION

[0044] It is worth noting that the raw materials used in the present invention are all common commercially available products, and their sources are not specifically limited.

[0045] The following sources of raw materials are provided for illustrative purposes:

[0046] Example 1

[0047] Combination Figure 1 As shown, this embodiment provides a method for evaluating the grid-connected performance of a power station, comprising the following steps: Step 1, collecting key parameters of the grid-connected performance of the power station, wherein the power station includes an energy storage power station, a photovoltaic power station and a wind power station, and the key parameters of the energy storage power station include at least active power, reactive power, power factor, charge and discharge response time, charge and discharge adjustment time, charge and discharge conversion time, overload capacity, rated energy, rated power energy conversion efficiency, power quality, high voltage ride-through, and low voltage ride-through; the key parameters of the photovoltaic power station and the wind power station include at least active power, high voltage ride-through, and low voltage ride-through.

[0048] Step 2: Test each key parameter; compare the test results with the pre-set qualified conditions; judge the performance through the comparison results, and then complete the evaluation of the grid-connected performance of the power station.

[0049] In this embodiment, the testing process of active power includes the following steps:

[0050] First, find the starting transition point: find the first point beyond the transition range and record its subscript i, and use the subscript to reverse the order. When the active power P corresponding to the current subscript i is i The value minus the active power P corresponding to the next subscript i+1 value, where i is 1, 2, 3, etc.; the target value is set to N×P N , where N takes a negative value when in the charging state and a positive value when in the discharging state. When N takes a negative value, the active power P corresponding to the current index i i The value minus the active power P corresponding to the previous subscript i-1 When the difference between the values ​​is less than or equal to 0, the current active power P i The value is taken as the value corresponding to the starting transition point. When N takes a positive value, the active power P corresponding to the current index i i The value minus the active power P corresponding to the previous subscript i-1 When the difference between the values ​​is greater than or equal to 0, the current active power P i The data corresponding to the value is the data of the starting transition point. It should be explained that P Nis the rated value of active power, which is provided by the station; whether to make a transition depends on whether it exceeds the target value ±P N 2% range, at this time N is 1. Second, find the end transition point: find the entry target value ±P N The first point of the 2% floating range is the entry point. If the target value is negative, when the current value minus the next value is less than or equal to 0, the data corresponding to the current value is the data of the end transition point. If the current value is positive, the current point is the end transition point when the current value minus the next value is greater than or equal to 0. Third, calculate the response time: the time corresponding to the position when the transition data reaches 0.9 times the end transition point - the time when the transition starts. Fourth, calculate the adjustment time: the time corresponding to the position when the transition data reaches the end transition point - the time when the transition starts; it should be noted that, considering that some data has not reached the target value, but remains stable within the normal floating range of the target value, the time corresponding to the point after the upward or downward direction changes is taken. Fifth, calculate the measured average value: start timing from the subscript position of the start transition point, and take the active value of 15S from the position 15S after the current position to find its average value. Control accuracy: (measured average value - N×P N ) / P N × 100%, where the result is the absolute value.

[0051] Specifically, the input process is: upload two csv files, the first column of each csv file is time in units of S. The second column is active power in units of W. The second column needs to be converted to MW, 1MW = 1000000W. Output results: Generate corresponding charts based on time data and active power. And obtain the measured average value (MW), control accuracy (%), response time, and adjustment time.

[0052] Specifically, the test process of active power is exemplified, and the input test data includes: the input data of active power increase file and active power reduction file in the active power regulation capability test folder. The corresponding test results include the active power increase regulation capability test results and the active power reduction regulation capability test results. The following Table 1 shows the data of the active power increase regulation capability test, and Table 2 shows the data of the active power reduction regulation capability test. Among them, Figure 2 The curve chart after the data test corresponding to Table 1; Figure 3 This is the curve chart after the data test corresponding to Table 2.

[0053] Table 1 Data of active power regulation capability test

[0054]

[0055]

[0056] Table 2 Data of active power reduction regulation capability test

[0057]

[0058] The data in Tables 1 and 2 above show that the conclusions we can draw are: when testing with increased power, the longest response time is 136.7s, the longest adjustment time is 249.5s, and the maximum control deviation is 1.85%; when testing with reduced power, the longest response time is 522.2s, the longest adjustment time is 826.4s, and the maximum control deviation is 1.15%. According to the standards GB / T36548-2018 / 7.2.1 and GB / T36547-2018 / 6.2.3, we can know that the data is qualified. It should be noted that if the data is not suitable, it needs to be retested.

[0059] In this embodiment, the process of testing the reactive power regulation capability is as follows: First, find the starting transition point, and calculate the average value of active power and reactive power within 30 seconds from the starting transition point (it is necessary to confirm that there is at least 30 seconds of data between the current starting transition point and the next starting transition point). Second, generate a table. When the table generates a chart, the measured value of reactive power / QN, where the unit of the measured value of reactive power is Mvar, Q N is the rated reactive power, which is similar to P N Equal, with the target value N×P N N is the X-axis, charging is negative, discharging is positive, and N is 1 at this time; finally a chart is generated.

[0060] Specifically, the input process is as follows: four csv files are uploaded, namely charging inductive reactive power, charging capacitive reactive power, discharging inductive reactive power, and discharging capacitive reactive power. Each csv file contains three columns, the first column is time, in seconds; the second column is active power value, in MW; the third column is reactive power value, in Mvar. The output result is: the reactive power regulation capacity table of the charging state and the reactive power regulation capacity table of the discharging state are output respectively through the algorithm calculation results, and the picture is generated by the principle of charging as negative and discharging as positive and the two regulation capacity tables.

[0061] Exemplarily, for the reactive power regulation capability test, the test data is input as follows: four files are input in the reactive power regulation capability test folder: charging inductive reactive power, charging capacitive reactive power, discharging inductive reactive power, and discharging capacitive reactive power. The corresponding test results include the reactive power regulation capability test results under charging state and the reactive power regulation capability test results under discharging state. Table 3 below shows the data of the reactive power regulation capability test under charging state, and Table 4 shows the data of the reactive power regulation capability test under discharging state. Among them, Figure 4 It is the envelope diagram after the data test corresponding to Table 3 and Table 4.

[0062] Table 3 Data of reactive power regulation capability test under charging state

[0063]

[0064] Table 4 Data of reactive power regulation capability test under discharge state

[0065]

[0066] The data in Table 3 and Table 4 above show that the conclusion is: reactive power range: -43.70 MVar to 53.10 MVar. According to the standards GB / T36548-2018 / 7.2.2 and GB / T36547-2018 / 6.1.2, it can be known that the data is qualified. Figure 4 As shown in the figure, when the trend of inductive reactive data is not similar to the symmetrical form of capacitive reactive data, it is considered as unqualified data. When unqualified data appears, you can choose to retest according to actual needs. It should be noted that 0P N 0 times in P is 0, but in P N When it is 0 and the state is floating, the data is still floating.

[0067] In this embodiment, the test process of the charge and discharge response time includes the following steps: First, find the starting transition point. Among them, whether the transition needs to be determined whether it exceeds P N 2% range; it should be noted that the target value is N×P N Second, when the data transition reaches the rated value P for the first time N When the value is 90% of the value, record the time and subtract the time point when the data transition starts. The resulting time is the response time.

[0068] Specifically, the input process is: two csv files of charging data and discharging data are grouped together, and a total of three groups of data are uploaded. Each csv file contains two columns, the first column is time, the unit is s; the second column is active power, the unit is W. The output result is: output a table and three charts, the chart uses active power as the Y axis unit MW, and time as the X axis unit s, mainly including the number of tests and response time (s). The number of tests is three times, corresponding to the calculation results of each group of data. See the standard results for examples.

[0069] Exemplarily, the charge and discharge response time is tested, and the test data is input: the data of charging first response, charging second response, charging third response, discharging first response, discharging second response, and discharging third response are input in the charge and discharge response time test folder. The corresponding test results include the charging response time test results and the discharging response time test results. The following Table 5 shows the data of the charging response time test, and Table 6 shows the data of the discharging response time test. Among them, corresponding to the data in Table 5, Figure 5-Figure 7 The curves corresponding to the first, second and third charging response times are shown in Table 6. Figure 8-Figure 10 The graphs correspond to the first, second and third discharge response times respectively.

[0070] Table 5 is the charging response time test

[0071] Number of tests Response time(s) first 0.680 Second time 0.450 The third time 0.871

[0072] Table 6 is the data of the discharge response time test

[0073] Number of tests Response time(s) First Test 0.840 Second test 1.081 Third test 0.900

[0074] The data in Table 5 and Table 6 above show that the conclusion is that the charging response time should be up to 0.871s, and the discharging response time should be up to 1.081s. Based on the standards: GB / T36548-2018 / 7.8 and GB / T36547-2018 / 6.2.3.

[0075] In this embodiment, the test process of the charge and discharge adjustment time includes the following steps: First, find the starting transition point. Among them, whether to transition needs to determine whether it exceeds P N ±(2%×P N ) range. Among them, the target value is N×P N , at this time N is 1. Second, when the data transition reaches the target value and the active power deviation of the second column is controlled at P N ±(2%×P N ) range; record the time and subtract the start time of the data transition.

[0076] Specifically, the input process is: two csv files of charging data and discharging data are grouped together, and a total of three groups of data are uploaded. Each csv file contains two columns, the first column is time, the unit is s; the second column is active power, the unit is MW. The output result is: output a table and three charts, the chart uses active power as the Y axis, the unit is MW, and time as the X axis, the unit is s, mainly including the number of tests and response time. The number of tests is three times, corresponding to the calculation results of each group of data.

[0077] For example, for the test of charge and discharge adjustment time, the test data input is: input data charging first adjustment, charging second adjustment, charging third adjustment, discharging first adjustment, discharging second adjustment, and discharging third adjustment in the charge and discharge response time test folder. The corresponding test results include the charge adjustment time test results and the discharge adjustment time test results. The following Table 7 shows the data of the charge adjustment time test, and Table 8 shows the data of the discharge adjustment time test. Among them, corresponding to the data in Table 7, Figure 11-13The curves corresponding to the first, second and third charging adjustment time are shown in Table 6. Figure 14-16 The graphs correspond to the first, second and third discharge adjustment times respectively.

[0078] Table 7 shows the data of the charge regulation time test

[0079] Number of tests Adjustment time(s) first 0.680 Second time 0.450 The third time 0.871

[0080] Table 8 is the data of the discharge regulation time test

[0081] Number of tests Adjustment time(s) First Test 0.840 Second test 1.081 Third test 0.900

[0082] The data in Table 7 and Table 8 above show that the conclusion is: the longest charging adjustment time is 0.871s, and the longest discharging adjustment time is 1.081s. Based on the standards: GB / T36548-2018 / 7.9; GB / T36547-2018 / 6.2.3.

[0083] In this embodiment, the test process of the charge-discharge conversion time includes the following steps: first, finding a charge state equal to or less than P N × 90% of the discharge state is equal to or greater than P N ×90% of the position and record it. Among them, whether the transition is to determine whether it exceeds P N The target value is N×P N . Second, the time recorded later minus the time recorded previously is the conversion time. Specifically, the input process is: one csv file of charging to discharging data is a group, and a total of six groups of data are uploaded. Each csv file contains two columns. The first column is time, in seconds; the second column is active power, in W. The output result is: Output a

[0084] The table and three charts, with active power as the Y-axis unit MW and time as the X-axis unit S, mainly include the number of tests and response time (s). The number of tests is three times, corresponding to the calculation results of each set of data.

[0085] For example, for the test of charge-discharge conversion time, the test data is input: in the charge-discharge response time test folder, input data charge-to-discharge first conversion, charge-to-discharge second conversion, charge-to-discharge third conversion, discharge-to-charge first conversion, discharge-to-charge first conversion, discharge-to-charge first conversion, discharge-to-charge first conversion. The corresponding test results include the charge-to-discharge conversion time test results and the discharge-to-charge conversion time test results. The following Table 9 shows the data of the charge-to-discharge conversion time test, and Table 10 shows the data of the discharge-to-charge conversion time test. Among them, corresponding to the data in Table 9, Figure 17-Figure 19 The curves corresponding to the first, second and third charge-to-discharge conversion times are shown in Table 10. Figure 20-Figure 22 The graphs correspond to the first, second and third discharge to charge conversion times respectively.

[0086] Table 9 Data of charge to discharge conversion time test

[0087] Number of tests Conversion time(s) first 0.680 Second time 0.450 The third time 0.871

[0088] Table 10 Data of discharge to charge conversion time test

[0089] Number of tests Adjustment time(s) First Test 0.840 Second test 1.081 Third test 0.900

[0090] The data in Tables 9 and 10 above show that the conclusion is that the longest charge-to-discharge conversion time is 0.871s, and the longest discharge-to-charge conversion time is 1.081s. Based on standards: GB / T36548-2018 / 7.10; GB / T36547-2018 / 6.2.3.

[0091] In this embodiment, the overload capacity test process includes the following steps: taking -1.1 times PN as an example, finding the end point of the transition into the target value and the start point of the transition away from the target value, calculating the time difference between the two points and the average value. N 2% range; target value is N×P N . Specifically, the input process is: input four csv files, charging 1.2 times power file, charging 1.1 times power file, discharging 1.2 times power file, discharging 1.1 times power file. Each file contains two columns, time and power. The output results are: two tables, charging and discharging, charging 1.2 times and 1.1 times.

[0092] For example, for the overload capacity test, the test data is input: the data in the overload capacity test folder are input as follows: charging 1.1 times data, charging 1.2 times data, discharging 1.1 times data, and discharging 1.2 times data. The corresponding test results include the charging state overload capacity test results and the discharging state overload capacity test results. The following Table 11 shows the data of the charging state overload capacity test, and Table 12 shows the data of the discharging state overload capacity test. Among them, corresponding to the data in Table 11, Figure 23-Figure 24 Corresponding to charging status 1.1P N , 1.2P N Curve diagram of overload capacity test; corresponding to the data in Table 12, Figure 25-26 Corresponding to the discharge state 1.1P N , 1.2P N Graph of overload capacity test.

[0093] Table 11 Data of charging state overload capacity test

[0094] Active power setting value Measured average value (MW) Request time(s) Measured time(s) <![CDATA[-1.1P N ]]> -44.263 600 613 <![CDATA[-1.2P N ]]> -48.139 60 71

[0095] Table 12 Data of overload capacity test in discharge state

[0096] Active power setting value Measured average value (MW) Request time(s) Measured time(s) <![CDATA[1.1P N ]]> 44.046 600 617 <![CDATA[1.2P N ]]> 47.397 60 72

[0097] The data in Tables 11 and 12 above show that the maximum overload for charging is -49.12MW, and the maximum overload for discharging is 47.51MW. According to the standard: GB / T36548-2018 / 7.3.

[0098] In this embodiment, the test process for the rated energy includes the following steps: N Take the example of finding the end point of the transition into the target value and the start point of the transition out of the target value to calculate the time difference and average value between the two points. Among them, whether to transition needs to determine whether it exceeds the 2% range of PN. The target value is N×P N .

[0099] Specifically, the input process is: one charge and one discharge data is a group, a total of three groups of data. One data is 0.2s, including the time column, the energy W_fund@POWER / 0_AVG[Wh] column, and the power P_fund@POWER / 0_AVG[W] column. The auxiliary energy consumption Wc (MWh) during charging and the auxiliary energy consumption WD (MWh) during discharging need to be uploaded. If not uploaded, the default value is 0. The output result is: a table, respectively for charging and discharging, charging 1.2 times and 1.1 times.

[0100] For example, for the rated energy test, the test data is input: the data of the first charge, the first discharge, the second charge, the second discharge, the third charge, and the third discharge are input in the rated energy test folder. The corresponding rated energy test results are shown in Table 13.

[0101] Table 13 Rated energy test data

[0102]

[0103]

[0104] Among them, for the energy storage system whose auxiliary energy consumption is supplied by itself, W C =0,W D =0. C =(E C1 +W C1 +E C2 +W C2 +E C3 +W C3 ) / 3; E D =(E D1-W D1 +E D2- W D2 +E D3- W D3 ) / 3. The data in Table 13 above show that the conclusion is: the average charging energy is 0.795MWh, and the average discharging energy is -0.021MWh. Based on the standard: GB / T36548-2018 / 7.11.

[0105] In this embodiment, the test process of rated power energy conversion efficiency includes the following steps: First, single energy conversion efficiency (%) = total charging energy Ec / total discharging energy E D , where Ec and E D The unit is MWh. Second, rated power energy conversion efficiency η (%) = [(E D1 -W D1 ) / (E C1 +W C1 )+(E D2 -W D2 ) / (E C2 +W C2 )+(E D3 -W D3 ) / (E C3 +W C3 )] / 3. Specifically, the input process is: call the total energy of three charges and three discharges in the rated energy test, the auxiliary energy consumption Wc (MWh) during charging, and the auxiliary energy consumption WD (MWh) during discharging. The output result is: a table.

[0106] For example, the test data input is: total energy of three charges and three discharges, auxiliary energy consumption Wc (MWh) during charging, auxiliary energy consumption WD (MWh) during discharging. The corresponding test results are shown in the data recorded in Table 14.

[0107] Table 14 Rated power energy conversion efficiency test

[0108]

[0109] It should be noted that for energy storage systems whose auxiliary energy consumption is supplied by themselves, W C =0,W D =0. η = 1 / 3*[(E D1 -W D1 ) / (E C1 +W C1 )+(E D2 -W D2 ) / (E C2 +W C2 )+(E D3 -WD3 ) / (E C3 +W C3 )]. The above data show that the conclusion is: rated power energy conversion efficiency: the conversion efficiency is 24.4%. According to the standard: GB / T36548-2018 / 7.12. It should be noted that E C1 is the total energy of the first charge; E C2 E is the total energy of the second charge; C3 The total energy of the third charge; E D1 is the total energy of the first discharge; E D2 is the total energy of the second discharge; E D3 is the total energy of the third discharge.

[0110] In this embodiment, the test process for power quality includes the following steps: Statistics of the harmonic voltage (95% probability maximum value) at the grid connection point: (1) Calculate the average value of the fundamental voltage (V) of phases ABC respectively. The calculation result is the corresponding fundamental voltage position in the table. (2) Calculate each data / fundamental voltage in each phase except the fundamental voltage respectively, and calculate the 95% probability maximum value of each column of the result. The calculation results of each column are stored in Table 15 by item and in sequence. Referring to the limit values ​​in Table 15 below, the limit value of odd items is 2.1, and the limit value of even items is 1.2. (3) After the table data is generated, compare the value of each phase and each row with the corresponding limit value. When the row value is greater than the limit value, the power quality test is judged as unqualified.

[0111] Specifically, the input process is: two csv files, each with 154 columns of data. The first column is time, in seconds, the third column is the fundamental voltage of phase A (V), represented by U1_hRMS@POWER / 0[1][V], and the fourth to the fifth columns correspond to the 2nd to 50th harmonic voltage values ​​of phase A. The fifth column is the fundamental voltage of phase B (V), represented by U2_hRMS@POWER / 0[1][V], and the fifth to the tenth columns correspond to the 2nd to 50th harmonic voltage values ​​of phase B. The 107th column is the fundamental voltage of phase C (V), represented by U3_hRMS@POWER / 0[1][V], and the tenth to the tenth columns correspond to the 2nd to 50th harmonic voltage values ​​of phase C. The second data structure is the same. The output result is: a table containing the corresponding 2nd to 50th harmonic current content (%), fundamental voltage, and limit value.

[0112] Example, test data input: charging state 100% P N Harmonic voltage data and discharge state 100% P N Harmonic voltage data. See Table 15 for the corresponding output result data.

[0113] Table 15

[0114]

[0115]

[0116] The data in Table 15 above show that the conclusion is that if the 2-50th harmonic voltage content does not exceed the number in the limit corresponding to the limit, the harmonic voltage content is qualified.

[0117] First, statistics on the inter-harmonic voltage (95% probability maximum value) at the grid connection point: (1) Calculate the average value of the fundamental voltage (V) of phases ABC respectively. The calculation result is the corresponding fundamental voltage position in the table. (2) Calculate each data / fundamental voltage in each phase except the fundamental voltage respectively, and calculate the 95% probability maximum value of each column of the result. Store the calculation results of each column in Table 16 by item and in sequence. Refer to the limit values ​​in Table 16 below. When the inter-harmonic frequency is 75Hz, the limit value is 0.16, and the remaining limit values ​​are 0.4. (3) After the table data is generated, compare the value of each phase and each row with the corresponding limit value. When the row value is greater than the limit value, the power quality test is judged as unqualified.

[0118] Specifically, the input process is: two csv files, each with 154 columns of data. The first column is time, in seconds, followed by the corresponding data for each phase. Output result: a table containing the 2nd to 50th harmonic current content (%), fundamental voltage, and limit value for each corresponding phase.

[0119] For example, test data input: input the charge and discharge interharmonic voltage CSV or Excel data respectively. The corresponding test results are shown in Table 16.

[0120] Table 16

[0121]

[0122] The data in Table 16 above show that the conclusion is: if the content rate of the 2nd to 25th simple harmonic voltage is not greater than the limit value, the inter-grid harmonic voltage (95% probability maximum value) is statistically qualified, otherwise it is unqualified.

[0123] Second, for the statistics of harmonic currents at the grid connection point, it should be noted that the comparison table of the allowable values ​​of harmonic currents injected into the public connection point is as follows: (1) The allowable value of harmonic current under the actual short-circuit capacity is calculated by the benchmark short-circuit capacity corresponding to the standard voltage and the allowable value of harmonic current corresponding to the harmonic order = the minimum short-circuit capacity of the public connection point / benchmark short-circuit capacity*the allowable value of the nth harmonic current in the table. (2) The allowable value of the nth harmonic current calculated by the above formula × (the power consumption agreement capacity of the jth user / the power consumption equipment capacity of the public connection point) 1 / a. (3) When n is 3, 5, 7, 11, and 13, a corresponds to 1.1, 1.2, 1.4, 1.8, and 1.9 respectively. When n is equal to 9 or greater than 13 or equal to an even number, a=2. (4) Determine whether the value of each column is greater than 0.5%. If it is greater, it is judged as unqualified. Specifically, the input process is: input the csv file of charging harmonic current and discharge point harmonic current. The output result is: a table containing the corresponding 2nd to 50th harmonic current content (%), fundamental voltage, and limit value.

[0124] For example, test data input: input charging and discharging harmonic current csv or excel files respectively. And input four calculation parameters: power supply equipment capacity, user agreement capacity, access point voltage kV, and minimum short-circuit capacity of public connection point. The test results are shown in Table 17 below.

[0125] Table 17

[0126]

[0127] The data in Table 17 above show that the conclusion is: Grid-connected point harmonic current statistics: If the harmonic current value of each item does not exceed the limit, the conclusion is: Grid-connected point harmonic current statistics are qualified.

[0128] Third, the three-phase voltage imbalance test: The input process is: two csv files, each of which has 2 columns of data. The first column is the time, the unit is s, and the second column is the state of 100% PN, the unit is %. The output results are: (1) Calculate the maximum value of the second column and the 95% probability maximum value of the second column. (2) Determine whether the maximum value is greater than 4 and whether the 95% probability maximum value is greater than 2. If greater, it is judged as unqualified.

[0129] For example, test data input: input the charge and discharge voltage imbalance test data in CSV or Excel. The test results are shown in Table 18.

[0130] Table 18

[0131] Power range (100% PN) Maximum value (%) Limits 95% Maximum value (%) Limits Charging status 0.846 4 0.519 2 Discharge status 0.576 4 0.407 2

[0132] The data in Table 18 above show that the conclusion can be drawn as follows: if the maximum value or 95% of the maximum value is greater than the limit value following the maximum value, the three-phase voltage unbalance is qualified, otherwise it is unqualified.

[0133] Fourth, for the bus flicker test: calculate the maximum value of the second column, the minimum value of the third column, and the average value of the fourth column. Specifically, input: two csv files, each with 4 columns of data; the first column is time, the unit is s. Output: the table shows the maximum, minimum, and average values ​​of the short flash data. Exemplary, test data input: input charging and discharging flicker test csv or excel data. The test results are shown in Table 19. It should be noted that Pst_L1 represents short-time flicker 1; Pst_L2 represents short-time flicker 2; Pst_L3 represents short-time flicker 3.

[0134] Table 19

[0135]

[0136] Fifth, for DC component test: (1) Calculate rated power × 1000000 / nominal voltage during measurement / The unit for page input is KV, which needs to be multiplied by 1000 for calculation. (2) Calculate each value in the second column / (calculated rated power / nominal voltage during measurement / ), the result is converted into percentage and three decimal places are retained. (3) Determine whether the value of each column is greater than 0.5%. If so, it is considered unqualified.

[0137] Specifically, the input process is: upload a total of six csv files, namely charging status (100%P N ) DC component of each phase, charging state (66%P N ) DC component of each phase, charging state (33%P N ) The DC component data of each phase, the same as the discharge. Each of them has 2 columns of data. The first column is time, in seconds, and the second column is 100%P N The unit is %. You also need to input the surge voltage 110kv / 35KV during measurement. For example, test data input: Input different P for charging or discharging N Multiple DC component test csv or excel file data and access point voltage value. Refer to Table 20 for test results.

[0138] Table 20

[0139]

[0140] The data in Table 20 above show that the conclusion is: if the DC component in different states does not exceed the proportion limit (0.5) or the DC component of each phase is not greater than the DC component limit, the DC component test is qualified. Otherwise, it fails.

[0141] In this embodiment, the process of simulating the actual frequency disturbance test includes: (1) recording the actual active minimum value, recording the theoretical active minimum value, recording the theoretical active start value-actual active minimum value, recording as A, recording the theoretical active start value-theoretical active minimum value as B, C=A / B×100. (2) First, determine the data whose actual active power is not equal to 0, and then determine whether there is a value greater than 50.04 in the two frequency data with the same subscript or before and after the subscript. If there is a value greater than 50.04, return the first value of the theoretical active power-the current actual active power value. Store in a list. After traversing the complete column data, add all the values ​​in the list. (3) Determine the data whose actual active power is not equal to 0 again. Under this premise, determine whether there is a value greater than 50.04 in the range of the frequency data corresponding to the subscript and the floating range before and after the subscript of 1. If there is, return the first value of the theoretical active power data-the theoretical active power value corresponding to the current subscript, and store the result in another list. After traversing the complete column data, add all the values ​​in the list. (4) The ratio of the sum calculated in (2) to the sum calculated in (3) × 100. (5) Calculate the primary frequency modulation pass rate (%): [C + (4)] / 2. It should be noted that the actual active data, frequency data, theoretical active data and time can also be used to calculate the integral.

[0142] Specifically, the input process is: input 8 disturbance data under different states, the first column is time data unit s, the second column is actual active data unit MW, the third column is frequency data unit Hz, and the fourth column is theoretical active data unit MW. The output result is the output parameter index table data and the fluctuation upper and lower winding diagrams. Exemplarily, the test data input: input the corresponding step upper and step lower winding CSV or EXCEL files in the simulated actual step disturbance folder. The test results are shown in Table 21.

[0143] Table 21

[0144]

[0145]

[0146] In this embodiment, the active power test process of the new energy includes the maximum measurement value of the active power change, the active power control capability test, and the high and low voltage test; it should be noted that the new energy includes wind power and photovoltaic power, and specifically includes the following steps:

[0147] First, the maximum measured value of active power change: (1) Maximum limit of active power change in 1 minute MW: calculated according to the installed capacity of the photovoltaic power field. If the installed capacity of the photovoltaic power field is less than 30MW, the standard change rate in one minute is 3. If the installed capacity of the photovoltaic power field is between 30-150MW, the standard change rate in one minute is required to be installed capacity / 10. If the installed capacity of the photovoltaic power field is greater than 150MW, the standard change rate in one minute is required to be 15. (2) Maximum limit of active power change in 10 minutes MW: calculated according to the installed capacity of the photovoltaic power field. If the installed capacity of the photovoltaic power field is less than 30MW, the standard change rate in one minute is 10. If the installed capacity of the photovoltaic power field is between 30-150MW, the standard change rate in one minute is required to be installed capacity / 10. If the installed capacity of the photovoltaic power field is greater than 150MW, the standard change rate in one minute is required to be 15. (3) Maximum value of change rate in 1 minute: find the maximum and minimum values ​​in each minute of the file, calculate and record the difference between the maximum and minimum values, and calculate the maximum value of the difference after the calculation of one file is completed. The maximum value of the 10-minute rate of change is consistent with that of the 1-minute rate of change. (4) Whether it exceeds the standard: Determine whether the maximum value of the 1-minute rate of change and the maximum value of the 10-minute rate of change are greater than the corresponding maximum limit of active power change MW. If so, return yes; otherwise, return no. It should be noted that (1) and (2) calculate the qualified limit of active power change rate.

[0148] For example, test data input: input csv or excel files of automatic start, automatic stop, manual start, and manual stop. The test results are shown in Table 22. Maximum measured value of active power change of photovoltaic power station in 1 minute.

[0149] Table 22

[0150]

[0151] The data in Table 22 above show that it can be concluded that during the normal operation of the photovoltaic power station, the 1-minute change rate of active power does not exceed the change rate limit during the increase of solar irradiance, and meets the technical indicator requirements specified in Article 4.2.2 of the "Technical Regulations for Photovoltaic Power Station Access to Power System" (GB / T19964-2012).

[0152] Second, active power control capability test: (1) Actual power (MW): Before the transition begins, calculate the average value of the data two minutes before the transition start point. (2) Maximum power deviation (MW): (test point (MW) value - actual power) result takes the absolute value. (3) Control accuracy (%): target value minus the average value of active power takes the absolute value / target value × 100%. (4) Response time: the corresponding time difference from the transition start point to the point where the next transition target value × 90% is reached. The active power control response time of the electric field does not exceed 120s. This condition is used to judge whether it has reached the qualified basis. (5) Overshoot: within 2 minutes after the transition ends, the data takes the maximum and minimum values, the result of the maximum value - target value takes the absolute value, and the result of the minimum value - target value (test point) takes the absolute value, and then the maximum value of the above calculation results is taken. The result obtained / rated capacity × 100%. The active power control overshoot σ does not exceed 10% of the installed capacity of the wind farm. This condition is used to judge whether it has reached the qualified basis. For example, test data input: input wind power or photovoltaic active power control capability test csv or excel data. The test results are shown in Table 23.

[0153] Table 23 Active power control capability test data table

[0154]

[0155] The data in Table 23 above show that the control capability of the active power target value of the photovoltaic power station does not meet the technical index requirements specified in Article 8.1.2 of the "Test and Evaluation Method for Grid-connected Performance of Photovoltaic Power Stations" (NB / T32026-2015).

[0156] In this embodiment, the high and low voltage test process includes the following steps: 1. Read the voltage transition target value contained in the file name. 2. Read the voltage per unit value column data, find the first point that exceeds the first voltage value ±0.1, and find the first value greater than or equal to 0 (if it is a high voltage, find a value less than or equal to 0) by subtracting the current value from the previous value. This point is the starting transition point. Get the active power value and active power per unit value corresponding to this point. 3. Starting from the starting transition point found in the previous step, find the first value whose voltage data enters the range of ±0.1 of the voltage transition target value. The current value - the next value, whose result is less than or equal to 0 (if it is a high voltage, find the first value whose result is greater than or equal to 0). This point is the ending transition point. 4. From the ending transition point, find the first value that exceeds the voltage transition target value within the range of ±0.1, which is the voltage hold end point. 5. Take the voltage data and voltage per unit value data from the ending transition point to the voltage hold end point. Calculate the average value of the data in the second half of this interval. The average value is the unit value of the actual drop amplitude and the nominal value (actual value). 6. The time from the start transition point to the end point of voltage retention is the fault duration. 7. The time from the voltage recovery moment to the power recovery steady-state value: the time corresponding to the first point within the range of ±0.01 of the power unit value at the start transition point from the end point of voltage retention - the time corresponding to the end point of retention. 8. Reactive current steady-state mean: the reactive current data corresponding to the voltage start transition point to the end point of voltage retention are used to calculate the average value of the reactive current in the second half and the reactive current unit value.

[0157] Example 2

[0158] The present embodiment provides a power station grid-connected performance evaluation system, which is used to execute a power station grid-connected performance evaluation method recorded in Example 1. Specifically, the system includes an active power control performance test module, a reactive power control performance test module, an energy storage power station charge and discharge response time test module, an energy storage power station charge and discharge adjustment time test module, an energy storage power station charge and discharge conversion time test module, an energy storage power station overload capacity test module, an energy storage power station rated power energy conversion efficiency test module, a power quality test module, and an energy storage power station primary frequency modulation test module; wherein the active power control performance test module is used to test the active power of energy storage power stations, photovoltaic power stations and wind power stations; the reactive power The control performance test module is used to test reactive power; the energy storage power station charge and discharge response time test module is used to test the charge and discharge response time; the energy storage power station charge and discharge regulation time test module is used to test the charge and discharge regulation time; the energy storage power station charge and discharge conversion time test module is used to test the charge and discharge conversion time; the energy storage power station overload capacity test module is used to test the overload capacity; the energy storage power station rated power energy conversion efficiency test module is used to test the rated power energy conversion efficiency; the power quality test module is used to test the power quality; the energy storage power station primary frequency modulation test module is used to test the simulation of the actual frequency disturbance; the low voltage ride-through test module and the high voltage ride-through test module are used to test the corresponding high and low voltage tests.

[0159] The system also includes a dynamic reactive compensation device performance test module for testing dynamic reactive compensation, a synchronous phasor measurement unit (PMU) performance test module for testing synchronous phasors, and an AVC performance test module for testing AVC. The testing ideas of the dynamic reactive compensation device performance test module, the synchronous phasor measurement unit (PMU) performance test module, and the AVC performance test module are similar to the testing ideas of the reactive power control performance test module. The active power control performance test module, the reactive power control performance test module, etc. constitute the energy storage power station power control test module; the low voltage ride-through test module, the high voltage ride-through test module, etc. constitute the grid adaptability test module, which can test parameters such as voltage and frequency; the energy storage power station rated energy test module is used to test the rated energy.

[0160] Finally, it should be noted that the above content is only used to illustrate the technical solution of the present invention, rather than to limit the scope of protection of the present invention. Simple modifications or equivalent substitutions of the technical solution of the present invention by ordinary technicians in this field do not deviate from the essence and scope of the technical solution of the present invention.

Claims

1. A method for evaluating the grid-connected performance of a power station, characterized in that: The following steps are involved: Step 1: Collect key parameters of the grid-connected performance of the power station, where the power station includes energy storage power station, photovoltaic power station and wind power station. The key parameters of energy storage power stations include at least active power, reactive power, power factor, charge and discharge response time, charge and discharge adjustment time, charge and discharge conversion time, overload capacity, rated energy, rated power energy conversion efficiency, power quality, high voltage ride-through, and low voltage ride-through; the key parameters of photovoltaic and wind power stations include at least active power, high voltage ride-through, and low voltage ride-through; Step 2: Test each key parameter; compare the test results with the pre-set qualified conditions; judge the performance through the comparison results, and then complete the evaluation of the grid-connected performance of the power station.

2. A method for evaluating the grid-connected performance of a power station according to claim 1, characterized in that: The testing process of active power in the energy storage power station is: finding the starting transition point and the ending transition point; calculating the response time and the adjustment time; Calculate the measured average value and control the accuracy; Among them, find the first point beyond the transition range and record its subscript i, and use the subscript i to reverse the order and recursively calculate the active power P corresponding to the current subscript i i The value minus the active power P corresponding to the next subscript i+1 value, where i is 1, 2, 3, etc.; the target value is set to N×P N , where N takes a negative value when in the charging state and a positive value when in the discharging state. When N takes a negative value, the active power P corresponding to the current index i i The value minus the active power P corresponding to the previous subscript i-1 When the difference between the values ​​is less than or equal to 0, the current active power P i The value is used as the value corresponding to the starting transition point; Find the target value ±(2%×P N ) is the entry point. If the target value is negative, when the current value minus the next value is less than or equal to 0, the data corresponding to the current value is the data of the end transition point; if the current value is positive, when the current value minus the next value is greater than or equal to 0, the current point is the end transition point.

3. A method for evaluating the grid-connected performance of a power station according to claim 2, characterized in that: The process of testing the reactive power regulation capability is: finding the starting transition point and generating a table.

4. A method for evaluating the grid-connected performance of a power station according to claim 2, characterized in that: The test process of charge and discharge response time is as follows: find the starting transition point, when the data transition reaches P for the first time N When the value is 90% of the value, record the time and subtract the time point when the data transition starts. The resulting time is the response time.

5. A method for evaluating the grid-connected performance of a power station according to claim 1, characterized in that: The test process of charge and discharge regulation time is as follows: find the starting transition point; when the data transition reaches the target value and the active power deviation of the second column is controlled within P N ±(2%×P N ) within the range; record the time and subtract the start time of the data transition.

6. A method for evaluating the grid-connected performance of a power station according to claim 1, characterized in that: The test process of charge-discharge conversion time is: find the value less than or equal to P in the charging state N ×90% and greater than or equal to P in the discharge state N ×90% of the position and record it; the difference between the later recorded time and the earlier recorded time is the conversion time.

7. A method for evaluating the grid-connected performance of a power station according to claim 1, characterized in that: The test process for overload capacity is as follows: N×P N is the target value. At this time, N is 1 or -1. Find the end point of the transition to the target value and the start point of the transition away from the target value to calculate the time difference and the average value between the two points. Among them, whether to transition needs to determine whether it exceeds P N 2% range.

8. A method for evaluating the grid-connected performance of a power station according to claim 1, characterized in that: The power quality test includes statistics on harmonic voltage at the grid connection point, statistics on inter-harmonic voltage at the grid connection point, statistics on harmonic current at the grid connection point, test on three-phase voltage imbalance, test on bus flicker and test on DC component.

9. A method for evaluating the grid-connected performance of a power station according to claim 1, characterized in that: Tests in photovoltaic and wind power plants include active power change maximum measurement value and active power control capability test, high voltage and low voltage test.

10. A grid-connected performance evaluation system for a power station, characterized in that: A method for evaluating the grid-connected performance of a power station according to any one of claims 1 to 9, comprising an active power control performance test module, a reactive power control performance test module, an energy storage power station charge and discharge response time test module, an energy storage power station charge and discharge adjustment time test module, an energy storage power station charge and discharge conversion time test module, an energy storage power station overload capacity test module, an energy storage power station rated power energy conversion efficiency test module, a power quality test module and an energy storage power station primary frequency modulation test module; Among them, the active power control performance test module is used to test the active power of the energy storage power station, the active power of the photovoltaic and wind power stations; the reactive power control performance test module is used to test the reactive power; the energy storage power station charge and discharge response time test module is used to test the charge and discharge response time; the energy storage power station charge and discharge regulation time test module is used to test the charge and discharge regulation time; the energy storage power station charge and discharge conversion time test module is used to test the charge and discharge conversion time; the energy storage power station overload capacity test module is used to test the overload capacity; the energy storage power station rated power energy conversion efficiency test module is used to test the rated power energy conversion efficiency; the power quality test module is used to test the power quality; the energy storage power station primary frequency regulation test module is used to test the simulation of the actual frequency disturbance.

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