Data-driven synchronous generator inertia time constant evaluation method and apparatus

Abstract

The application provides a data-driven synchronous generator inertia time constant evaluation method, comprising the following steps: obtaining the nominal frequency and active power of a synchronous generator grid connection point, and frequency measurement data; obtaining a frequency deviation value according to the nominal frequency and the frequency, and obtaining an evaluation time when the frequency deviation value is equal to a frequency control dead zone; constructing an active average value expression based on the evaluation time to construct an active change amount expression and further construct a frequency expression to obtain an evaluation function; inversely deducing a theoretical frequency curve according to the frequency expression to correct the time scale of the measurement data; and based on average window integration, calculating the evaluation function according to the time scale corrected measurement data to obtain an inertia time constant evaluation value. The evaluation method provided by the application can reasonably and accurately evaluate the inertia time constant of the synchronous generator on the basis of time scale correction of the measurement data, and has guiding significance for real frequency support capability evaluation of a new energy station.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of synchronous generator inertia evaluation, and particularly relates to a synchronous generator inertia time constant evaluation method and device based on data driving. BACKGROUND

[0002] Under the guidance of the "double carbon" strategic goal, China is accelerating the construction of a new power system with a continuously increasing proportion of new energy. The development of new energy represented by wind and light will further accelerate, and the power system is gradually changing from the traditional alternating current system dominated by thermal synchronous generators to the power electronic hybrid AC / DC system dominated by wind, light and other new energy. The inertia and primary frequency modulation capability of the power system are gradually weakening, resulting in a significant deterioration of the frequency index of the power system after being disturbed. In order to cope with the frequency stability problem faced by the power system after large-scale grid connection of new energy power stations, it is urgent to provide virtual inertia frequency modulation capability for new energy power stations to enhance the support capability of the system frequency.

[0003] The virtual inertia control of the new energy station takes the frequency change rate as the input signal, changes the power reference value of the new energy station by adding frequency modulation power to the original power instruction, and aims to simulate the inertia response function of the synchronous generator. At present, the new energy station frequency modulation parameter evaluation method cannot reflect the real frequency support capability of the station. The rotational inertia of the synchronous generator is a self-inherent property, and the inertia time constant evaluation result of the synchronous generator can reflect the actual frequency support capability. Therefore, it is of great guiding significance to study the inertia time constant evaluation method of the synchronous generator for the real frequency support capability evaluation of the new energy station. How to evaluate the inertia time constant of the generator is the subject of the present application. SUMMARY

[0004] The present application provides a synchronous generator inertia time constant evaluation method based on data driving, which can reasonably and accurately evaluate the inertia time constant of the synchronous generator according to the measurement data collected at the grid connection point of the synchronous generator and the correction, and has important guiding significance for the real frequency support capability evaluation of the new energy station.

[0005] To achieve the above-mentioned purpose, the technical scheme adopted by the present application is as follows: a synchronous generator inertia time constant evaluation method based on data driving, comprising the following steps:

[0006] Obtaining the nominal frequency and measurement data of the grid connection point of the synchronous generator; the measurement data includes frequency and active power;

[0007] Obtaining the evaluation period and the frequency control dead zone of the power system where the synchronous generator is located;

[0008] Obtaining the frequency deviation value according to the nominal frequency and the frequency;

[0009] obtaining an evaluation moment according to the frequency deviation value being equal to the frequency control dead zone; the evaluation moment is a starting moment of the evaluation period;

[0010] constructing an active average value expression based on the evaluation moment; the active average value is an active power average value of the synchronous generator grid-connected point before the evaluation moment;

[0011] constructing an active change amount expression based on the active average value expression; the active change amount is a change amount of the frequency modulation active power of the synchronous generator grid-connected point relative to the active average value;

[0012] obtaining an inertia time constant preset value of the synchronous generator;

[0013] constructing a frequency expression based on the evaluation period, the active change amount and the inertia time constant preset value; the frequency expression is a relationship between the frequency at the end of the evaluation period and the frequency at the evaluation moment;

[0014] obtaining a theoretical frequency curve according to the frequency expression;

[0015] performing time scale correction on the measurement data according to the theoretical frequency curve;

[0016] replacing the inertia time constant preset value in the frequency expression with an inertia time constant evaluation value of the synchronous generator to obtain an evaluation function;

[0017] obtaining the inertia time constant evaluation value based on average window integration and the measurement data after the time scale correction.

[0018] Further, the frequency deviation value is an absolute value of the nominal frequency and the frequency difference.

[0019] Further, the active average value is an active power average value of the synchronous generator grid-connected point sampled at a preset sampling time interval within a preset time before the evaluation moment.

[0020] Further, the preset time is 1-3s, and the preset sampling time interval is 10-50ms.

[0021] Further, the frequency expression is a relationship expression between a frequency per unit, an active change amount per unit and the inertia time constant preset value.

[0022] Further, the evaluation function is:

[0023]

[0024] H in the formulaP an inertia time constant evaluation value of a synchronous generator * a power variation unit value, a total power variation unit value in a period from t0 to t1, t0 being an evaluation time, and t1 being an evaluation period, a frequency variation unit value in a period from t0 to t1, f * a frequency unit value.

[0025] Further, when a calculation result converges, the calculation result is outputted according to the evaluation function calculated based on average window integration and according to the time scale corrected measurement data, and the inertia time constant evaluation value is obtained according to the calculation result.

[0026] Further, a PMU is installed at a synchronous generator grid connection point, and the measurement data is obtained according to the PMU.

[0027] An apparatus for implementing the data-driven inertia time constant evaluation method of a synchronous generator, comprising a data processing unit, a calculation unit, and a modeling unit.

[0028] The data processing unit comprises:

[0029] a unit for obtaining a nominal frequency and measurement data of a synchronous generator grid connection point and transmitting the same to the calculation unit;

[0030] a unit for obtaining an evaluation period and transmitting the same to the calculation unit;

[0031] a unit for obtaining a frequency control dead zone of a power system in which the synchronous generator is located and transmitting the same to the calculation unit;

[0032] a unit for obtaining a preset inertia time constant value of a synchronous generator and transmitting the same to the modeling unit;

[0033] a unit for obtaining a theoretical frequency curve according to backstepping of the frequency expression;

[0034] a unit for time scale correcting the measurement data according to the theoretical frequency curve and transmitting the same to the calculation unit;

[0035] The calculation unit comprises:

[0036] a unit for obtaining a frequency deviation value according to the nominal frequency and the frequency;

[0037] a unit for obtaining an evaluation time according to the frequency deviation value being equal to the frequency control dead zone and transmitting the same to the modeling unit;

[0038] a unit for obtaining the inertia time constant evaluation value according to the evaluation function calculated based on average window integration and according to the time scale corrected measurement data.

[0039] The modeling unit is configured to:

[0040] construct an active average value expression based on the evaluation time;

[0041] construct an active change amount expression based on the active average value expression;

[0042] construct a frequency expression based on the evaluation period, the active change amount and the preset inertia time constant, and transmit the frequency expression to the data processing unit;

[0043] replace the preset inertia time constant in the frequency expression with an evaluated inertia time constant of a synchronous generator to obtain an evaluation function and transmit the evaluation function to the calculation unit.

[0044] Further, the calculation unit comprises a first calculation module and a second calculation module.

[0045] The first calculation module is configured to:

[0046] obtain a frequency deviation value according to the nominal frequency and the frequency;

[0047] obtain an evaluation time according to the frequency control dead zone when the frequency deviation value is equal to the frequency control dead zone, and transmit the evaluation time to the modeling unit;

[0048] The second calculation module is configured to:

[0049] calculate the evaluation function based on the measurement data after the time scale correction according to the average window integration to obtain the evaluated inertia time constant.

[0050] Compared with the prior art, the present application has the following beneficial effects:

[0051] The evaluation method disclosed by the present application can reasonably and accurately evaluate the inertia time constant of the synchronous generator based on the frequency, frequency change rate and active power data collected at the grid connection point of the synchronous generator.

[0052] The present application can determine the size of the inertia time constant of the synchronous generator based on the measurement data at the grid connection point of the synchronous generator and the corrected measurement data, which has important guiding significance for the evaluation of the real frequency support capability of the new energy station. BRIEF DESCRIPTION OF DRAWINGS

[0053] Figure 1 The figure is a flowchart of the data-driven inertia time constant evaluation method of the synchronous generator according to the present application;

[0054] Figure 2 The figure is an active power graph at the grid connection point of the synchronous generator in the example of the present application;

[0055] Figure 3 A figure of frequency correction result of the synchronous generator in the example of the application;

[0056] Figure 4 A figure of evaluation result of the inertia time constant evaluation value of the synchronous generator in the example of the application;

[0057] Figure 5 A structure diagram of the device in the application. DETAILED DESCRIPTION

[0058] In order to clearly illustrate the technical features of the scheme, the scheme will be described below through specific embodiments.

[0059] Referring to Figure 1 A data-driven-based inertia time constant evaluation method of a synchronous generator, comprising the following steps:

[0060] Obtaining the nominal frequency and measurement data of the grid connection point of the synchronous generator; the measurement data includes frequency and active power, and also includes frequency change rate; installing a PMU (Phasor Measurement Unit) at the grid connection point of the synchronous generator, and obtaining the measurement data according to the PMU; after obtaining the measurement data, performing unitization on the measurement data according to a unitization formula; the unitization formula is:

[0061]

[0062] In the formula, f * is the frequency unit value, f is the frequency measurement data, f N is the grid standard frequency, which is 50 Hz in China, is the frequency change rate measurement data, f is the frequency change rate measured by the PMU, is the frequency change rate unit value, P * is the active power, P is the active power measurement data, P is the active power measured by the PMU, P N is the rated power of the synchronous generator, and is obtained according to the rated power of the synchronous generator unit;

[0063] Obtaining an evaluation period;

[0064] Obtaining the frequency control dead zone Δf dead of the power system where the synchronous generator is located;

[0065] Obtaining the frequency deviation value according to the nominal frequency and the frequency; the frequency deviation value is the absolute value of the difference between the nominal frequency and the frequency, that is:

[0066] |Δf(t0)|=|f(t0)-f0|;

[0067] obtaining an evaluation moment according to the frequency deviation value being equal to the frequency control dead zone; the evaluation moment is a starting moment of the evaluation period; a formula for obtaining the evaluation moment is:

[0068] |Δf(t0)|=|f(t0)-f0|=Δfdead;

[0069] In the formula, Δf(t0) is a frequency deviation value at t0 moment, t0 is the evaluation moment, f(t0) is a frequency of the synchronous generator grid connection point at t0 moment, f0 is a nominal frequency of the synchronous generator grid connection point, Δf dead is the frequency control dead zone;

[0070] that is, the moment when the frequency deviation value is equal to the frequency control dead zone is the evaluation moment;

[0071] constructing an active average value expression based on the evaluation moment; the active average value is an active power average value of the synchronous generator grid connection point before the evaluation moment; the active average value is an active power average value of the synchronous generator grid connection point sampled at a preset sampling time interval within a preset time before the evaluation moment, preferably, further, the preset time is 1-3 s, and the preset sampling time interval is 10-50 ms; more preferably, the preset time is 1 s, the preset sampling time interval is 20 ms, and the active average value is:

[0072]

[0073] In the formula, P0 is the active average value, that is, the active power average value of the synchronous generator grid connection point sampled at the preset sampling time interval within the preset time before the evaluation moment, n is the preset time, i is a sampling serial number, and T s is the preset sampling time interval;

[0074] constructing an active change amount expression based on the active average value expression; the active change amount is a change amount of the frequency modulation active power of the synchronous generator grid connection point relative to the active average value; the active change amount expression is:

[0075] ΔP(t)=P(t)-P0;

[0076] In the formula, ΔP(t) is the active change amount at t moment, and t is time;

[0077] obtaining an inertia time constant preset value H of the synchronous generator;

[0078] constructing a frequency expression based on the evaluation period, the active change amount, and the inertia time constant preset value; the frequency expression is a relationship between the frequency at the end of the evaluation period and the frequency at the evaluation moment; the frequency expression is:

[0079]

[0080] obtaining a theoretical frequency curve according to the frequency expression;

[0081] performing time scale correction on the measurement data according to the theoretical frequency curve;

[0082] replacing the preset value of the inertia time constant in the frequency expression with the evaluation value of the inertia time constant of the synchronous generator to obtain an evaluation function; the evaluation function is:

[0083]

[0084] wherein H P is the evaluation value of the inertia time constant of the synchronous generator, ΔP * is the active power change per unit, is the total active power change per unit in the period t0-t1, t0 is the evaluation time, t1 is the evaluation period, is the frequency change per unit in the period t0-t1, f * is the frequency per unit.

[0085] obtaining the evaluation value of the inertia time constant based on the average window integral according to the evaluation function calculated by the time scale corrected measurement data.

[0086] The step of obtaining the evaluation value of the inertia time constant based on the average window integral according to the evaluation function calculated by the time scale corrected measurement data is:

[0087] calculating the evaluation function according to the numerical integral formula, outputting the calculation result when the calculation result converges, and obtaining the evaluation value of the inertia time constant according to the calculation result.

[0088] Referring to Figure 5 , the embodiment of the present application also provides a device for implementing the data-driven inertia time constant evaluation method of the synchronous generator, comprising a data processing unit, a calculation unit and a modeling unit; the data processing unit comprises a PMU installed at the grid connection point of the synchronous generator;

[0089] The data processing unit comprises:

[0090] is used for obtaining the nominal frequency and the measurement data of the grid connection point of the synchronous generator and transmitting them to the calculation unit;

[0091] is used for obtaining the evaluation period and transmitting it to the calculation unit;

[0092] is used for obtaining the frequency control dead zone of the power system where the synchronous generator is located and transmitting it to the calculation unit;

[0093] is used for obtaining the preset value of the inertia time constant of the synchronous generator and transmitting it to the modeling unit;

[0094] is used for obtaining a theoretical frequency curve according to the frequency expression;

[0095] for time correction of the measurement data according to the theoretical frequency curve and transmitting to the calculation unit;

[0096] the calculation unit:

[0097] for obtaining the frequency deviation value according to the nominal frequency and the frequency;

[0098] for obtaining the evaluation time according to the frequency deviation value equaling the frequency control dead zone and transmitting to the modeling unit;

[0099] for obtaining the inertia time constant evaluation value according to the evaluation function calculated based on the average window integration and the time corrected measurement data;

[0100] the modeling unit:

[0101] for constructing the active average value expression based on the evaluation time;

[0102] for constructing the active change amount expression based on the active average value expression;

[0103] for constructing the frequency expression based on the evaluation period, the active change amount and the inertia time constant preset value and transmitting to the data processing unit;

[0104] for obtaining the evaluation function by replacing the inertia time constant preset value in the frequency expression with the inertia time constant evaluation value of the synchronous generator and transmitting to the calculation unit.

[0105] Further, the calculation unit comprises a first calculation module and a second calculation module;

[0106] the first calculation module:

[0107] for obtaining the frequency deviation value according to the nominal frequency and the frequency;

[0108] for obtaining the evaluation time according to the frequency deviation value equaling the frequency control dead zone and transmitting to the modeling unit;

[0109] the second calculation module:

[0110] for obtaining the inertia time constant evaluation value according to the evaluation function calculated based on the average window integration and the time corrected measurement data.

[0111] The calculation of the evaluation time and the calculation of the active average value are respectively performed by the first calculation module, and the calculation of the evaluation function based on the average window integration is performed by the second calculation module, so that the calculation unit can be functionally divided and the calculation rate is improved.

[0112] Example

[0113] The evaluation method of the present disclosure is used to evaluate the inertia time constant of a synchronous generator of a power plant, and the evaluation process uses actual operation data of the synchronous generator of the power plant, as shown in Figure 2 .

[0114] From Figure 3 It can be seen that the present application corrects the time scale of the frequency data to align the theoretical frequency curve with the time scale of the active power measurement data, that is, the measurement data is corrected according to the theoretical frequency curve, and it can be proved that the frequency expression of the present disclosure can accurately calculate the inertia time constant. From Figure 4 It can be seen that using the evaluation method of the present disclosure, the inertia time constant of the synchronous generator can be extracted using measurement data by analyzing the frequency, frequency rate of change and active power of the synchronous generator.

[0115] From the calculation example, it can be seen that the evaluation method of the present application can reasonably and accurately evaluate the inertia time constant of the synchronous generator. According to the frequency, frequency rate of change and active power data collected at the grid connection point of the synchronous generator, the measurement data is corrected using the method of the present application, and the inertia time constant of the synchronous generator can be evaluated.

[0116] Therefore, the present application uses the above-mentioned data-driven synchronous generator inertia time constant evaluation method, which can determine the size of the inertia time constant of the synchronous generator based on the measurement data of the PMU at the grid connection point of the synchronous generator and on the basis of correcting the measurement data. Research on the evaluation method of the inertia time constant of the synchronous generator has important guiding significance for the evaluation of the real frequency support capability of new energy stations.

[0117] Finally, it should be noted that the above content is only used to illustrate the technical solutions of the present application, and is not a limitation on the protection scope of the present application. Simple modifications or equivalent replacements of the technical solutions of the present application made by those skilled in the art do not deviate from the essence and scope of the technical solutions of the present application.

Claims

1. A data-driven method for evaluating the inertial time constant of a synchronous generator, characterized in that: Includes the following steps: Obtain the nominal frequency and measurement data of the synchronous generator's grid connection point; the measurement data includes frequency and active power; Obtain the assessment period; Obtain the frequency control dead zone of the power system where the synchronous generator is located; The frequency deviation value is obtained based on the nominal frequency and the frequency; The evaluation time is obtained based on the frequency deviation value being equal to the frequency control dead zone; the evaluation time is the start time of the evaluation period. An expression for the average active power is constructed based on the assessment time; the average active power is the average active power of the synchronous generator grid connection point before the assessment time; Construct an expression for the change in active power based on the expression for the average active power value; The change in active power is the change in the frequency-regulated active power at the grid connection point of the synchronous generator relative to the average active power value. Obtain the preset value of the inertial time constant of the synchronous generator; A frequency expression is constructed based on the evaluation period, the change in active power, and the preset value of the inertial time constant; The frequency expression represents the relationship between the frequency at the end of the evaluation period and the frequency at the evaluation time. The theoretical frequency curve is obtained by reverse calculation based on the frequency expression. The measurement data are time-scaled and corrected according to the theoretical frequency curve. The evaluation function is obtained by replacing the preset value of the inertial time constant in the frequency expression with the evaluation value of the inertial time constant of the synchronous generator. The inertial time constant evaluation value is obtained by calculating the evaluation function based on the average window integral and the time-scaled corrected measurement data.

2. The data-driven synchronous generator inertial time constant evaluation method according to claim 1, characterized in that: The frequency deviation value is the absolute value of the nominal frequency and the frequency difference.

3. The data-driven synchronous generator inertial time constant evaluation method according to claim 2, characterized in that: The active power average is the average active power of the synchronous generator grid connection point sampled at a preset sampling time interval within a preset time period before the evaluation time.

4. The data-driven synchronous generator inertial time constant evaluation method according to claim 3, characterized in that: The preset time is 1 to 3 seconds, and the preset sampling time interval is 10 to 50 ms.

5. The data-driven synchronous generator inertial time constant evaluation method according to claim 3, characterized in that: The frequency expression is a relationship expression between the per-unit frequency value, the per-unit value of the active power change, and the preset value of the inertial time constant.

6. The data-driven synchronous generator inertial time constant evaluation method according to claim 5, characterized in that: The evaluation function is: In the formula, H P ΔP is the estimated value of the inertial time constant of a synchronous generator. * This is the per-unit value of the change in active power. This represents the per-unit value of the total change in active power during the time interval t1 from time t0, where t0 is the evaluation time and t1 is the evaluation period. f is the per-unit value of the frequency change during the time interval t1 from time t0. * This is the per-unit value for frequency.

7. The data-driven synchronous generator inertial time constant evaluation method according to claim 1, characterized in that: When calculating the evaluation function based on the average window integral and the time-scaled corrected measurement data, the calculation result is output when the calculation result converges, and the inertial time constant evaluation value is obtained based on the calculation result.

8. The data-driven synchronous generator inertial time constant evaluation method according to claim 1, characterized in that: A PMU is installed at the grid connection point of the synchronous generator, and the measurement data is obtained from the PMU.

9. An apparatus for implementing the data-driven synchronous generator inertial time constant evaluation method according to any one of claims 1-8, characterized in that: It includes data processing units, computing units, and modeling units; The data processing unit: Used to acquire the nominal frequency and measurement data of the synchronous generator's grid connection point and transmit them to the computing unit; Used to acquire the evaluation period and transmit it to the computing unit; Used to obtain the frequency control dead zone of the power system where the synchronous generator is located and transmit it to the computing unit; Used to obtain the preset value of the inertial time constant of the synchronous generator and transmit it to the modeling unit; Used to inversely deduce the theoretical frequency curve based on the frequency expression; Used to perform time-scale correction on the measurement data according to the theoretical frequency curve and transmit it to the calculation unit; The computing unit: Used to obtain a frequency deviation value based on the nominal frequency and the frequency; Used to obtain the evaluation time based on the frequency deviation value being equal to the frequency control dead zone and transmit it to the modeling unit; This is used to calculate the evaluation function based on the time-scaled corrected measurement data, using the average window integral, to obtain the inertial time constant evaluation value; The modeling unit: Used to construct an expression for the average active power based on the evaluation time; Used to construct an expression for the change in active power based on the expression for the average active power value; Used to construct a frequency expression based on the evaluation period, the change in active power, and the preset value of the inertial time constant, and then transmit it to the data processing unit; The function is used to replace the preset value of the inertial time constant in the frequency expression with the evaluation value of the inertial time constant of the synchronous generator to obtain the evaluation function and transmit it to the calculation unit.

10. The apparatus according to claim 9, characterized in that, The computing unit includes a first computing module and a second computing module; First calculation module: Used to obtain a frequency deviation value based on the nominal frequency and the frequency; Used to obtain the evaluation time based on the frequency deviation value being equal to the frequency control dead zone and transmit it to the modeling unit; Second calculation module: The evaluation function is used to calculate the inertial time constant evaluation value based on the time-scaled corrected measurement data using the average window integral.

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