Synchronous generator inertia time constant evaluation method and device based on data driving

Abstract

The invention provides a synchronous generator inertia time constant evaluation method based on data driving. The method comprises the following steps: acquiring nominal frequency, active power and frequency measurement data of a synchronous generator grid connection point; obtaining a frequency deviation value according to the nominal frequency and the frequency, and obtaining an evaluation moment when the frequency deviation value is equal to a frequency control dead zone; constructing an active average value expression based on the evaluation time so as to construct an active variation expression, and further constructing a frequency expression so as to obtain an evaluation function; reversely deducing a theoretical frequency curve according to the frequency expression so as to carry out time mark correction on the measurement data; and based on the average window integral, calculating an evaluation function according to the measurement data after the time mark correction to obtain an inertia time constant evaluation value. According to the evaluation method provided by the invention, on the basis of performing time mark correction on the measured data, the inertia time constant of the synchronous generator is reasonably and accurately evaluated by using the disturbed data, and the evaluation method has guiding significance for evaluating the real frequency supporting capability of a new energy station.

Description

Technical Field

[0001] The present invention relates to the technical field of synchronous generator inertia evaluation, and in particular to a synchronous generator inertia time constant evaluation method and device based on data drive. Background Art

[0002] Guided by the strategic goal of "dual carbon", China is accelerating the construction of a new power system with an increasing proportion of new energy. The development of new energy represented by wind and light will be further accelerated. The power system is gradually changing from a traditional AC system dominated by thermal synchronous machines to a power electronic AC / DC hybrid system dominated by new energy such as wind and light. The inertia and primary frequency regulation capabilities 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, it is urgent for new energy power stations to provide virtual inertia frequency regulation capabilities to enhance the support capacity for system frequency.

[0003] The virtual inertia control of the new energy station uses the frequency change rate as the input signal. By adding the frequency modulation power to the original power command, the power reference value of the new energy station is changed, aiming to simulate the inertia response function of the synchronous generator. At present, the frequency modulation parameter evaluation method of the new energy station cannot reflect the real frequency support capability of the station. The moment of inertia of the synchronous generator is an inherent property of itself. The evaluation result of the inertia time constant of the synchronous generator can reflect the actual frequency support capability. The study of the inertia time constant evaluation method of the synchronous generator has important guiding significance for the evaluation of the real frequency support capability of the new energy station. How to evaluate the inertia time constant of the generator is the subject of this invention. Summary of the invention

[0004] In view of the problems existing in the prior art, the present invention provides a data-driven synchronous generator inertia time constant evaluation method, which collects and corrects measurement data according to the synchronous generator grid-connected point, uses the disturbed data to reasonably and accurately evaluate the inertia time constant of the synchronous generator, and has important guiding significance for the evaluation of the real frequency supporting capacity of new energy stations.

[0005] To achieve the above object, the technical solution adopted by the present invention is as follows: a method for evaluating the inertia time constant of a synchronous generator based on data drive, comprising the following steps:

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

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

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

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

[0010] An active power average value expression is constructed based on the evaluation time; the active power average value is the active power average value of the synchronous generator grid connection point before the evaluation time;

[0011] An active power variation expression is constructed based on the active power average value expression; the active power variation is the variation of the frequency-modulated active power of the synchronous generator grid connection point relative to the active power average value;

[0012] Obtaining a preset value of the inertia time constant of a synchronous generator;

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

[0014] Obtaining a theoretical frequency curve by inverse deduction according to the frequency expression;

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

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

[0017] The inertia time constant evaluation value is obtained by calculating the evaluation function based on the measured data after the time scale correction based on the average window integration.

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

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

[0020] Furthermore, the preset time is 1 to 3 seconds, and the preset sampling time interval is 10 to 50 ms.

[0021] Furthermore, the frequency expression is a relationship expression between the frequency per unit value, the active power change per unit value and the preset value of the inertia time constant.

[0022] Furthermore, the evaluation function is:

[0023]

[0024] In the formula, HP is the estimated value of the inertia time constant of the synchronous generator, ΔP * is the per unit value of active power change, is the per unit value of the total active power change from time t0 to time t1, where t0 is the evaluation time and t1 is the evaluation period. is the per-unit value of the frequency change from time t0 to time t1, f * is the frequency per unit value.

[0025] Further, based on the average window integral, when the evaluation function is calculated according to the measured data after the time-scale correction, the calculation result is output when the calculation result converges, and the inertia time constant evaluation value is obtained according to the calculation result.

[0026] Furthermore, a PMU is installed at the grid-connected point of the synchronous generator, and the measurement data is obtained according to the PMU.

[0027] A device for implementing the data-driven synchronous generator inertia time constant evaluation method, comprising a data processing unit, a calculation unit and a modeling unit;

[0028] The data processing unit:

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

[0030] Used to obtain the evaluation period and transmit it to the computing unit;

[0031] Used to obtain the frequency control dead zone of the power system where the synchronous generator is located and transmit it to the calculation unit;

[0032] Used to obtain a preset value of the inertia time constant of the synchronous generator and transmit it to the modeling unit;

[0033] Used to obtain a theoretical frequency curve by inverse deduction according to the frequency expression;

[0034] Used to perform time-scale correction on the measurement data according to the theoretical frequency curve and transmit the time-scale correction to the calculation unit;

[0035] The computing unit:

[0036] Used to obtain a frequency deviation value according to the nominal frequency and the frequency;

[0037] Used to obtain an evaluation time according to the frequency deviation value being equal to the frequency control dead zone and transmit the evaluation time to the modeling unit;

[0038] for calculating the evaluation function to obtain the inertia time constant evaluation value based on the measured data corrected by the time scale based on the average window integration;

[0039] The modeling unit:

[0040] for constructing an active power average value expression based on the evaluation time;

[0041] Used to construct an active power variation expression based on the active power average value expression;

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

[0043] An evaluation function is obtained by replacing the preset value of the inertia time constant in the frequency expression with an evaluation value of the inertia time constant of the synchronous generator and transmitting the evaluation function to the calculation unit.

[0044] Further, the computing unit includes a first computing module and a second computing module;

[0045] The first calculation module:

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

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

[0048] The second calculation module:

[0049] The method is used for calculating the evaluation function based on the average window integration and the measured data after the time scale correction to obtain the inertia time constant evaluation value.

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

[0051] The evaluation method proposed in the present invention 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 synchronous generator grid connection point.

[0052] The present invention can determine the size of the inertia time constant of the synchronous generator based on the measurement data of the synchronous generator grid-connected point and on the basis of correcting the measurement data, which has important guiding significance for the evaluation of the real frequency supporting capacity of the new energy station. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Figure 1 It is a flow chart of a synchronous generator inertia time constant estimation method based on data drive of the present invention;

[0054] Figure 2 It is the active power diagram of the synchronous generator grid connection point in the calculation example of the present invention;

[0055] Figure 3 This is a diagram showing the frequency correction results of a synchronous generator in a calculation example of the present invention;

[0056] Figure 4 is a diagram showing the evaluation results of the inertia time constant evaluation value of the synchronous generator in the calculation example of the present invention;

[0057] Figure 5 It is a schematic diagram of the structure of the device in the present invention. DETAILED DESCRIPTION

[0058] In order to clearly illustrate the technical features of this solution, this solution is described below through a specific implementation method.

[0059] See also Figure 1 , a data-driven synchronous generator inertia time constant evaluation method, comprising the following steps:

[0060] Obtain the nominal frequency and measurement data of the synchronous generator grid-connected point; the measurement data includes frequency and active power, and also includes the frequency change rate; install PMU (Phasor Measurement Unit) at the synchronous generator grid-connected point, and obtain the measurement data according to the PMU; after obtaining the measurement data, standardize the measurement data according to the standardization formula; the standardization formula is:

[0061]

[0062] In the formula, f * is the frequency per unit value, f is the frequency measurement data, is the frequency measured by PMU, and f N The standard frequency of the power grid is 50Hz in my country. is the frequency change rate measurement data, is the frequency change rate measured by PMU, P is the per-unit value of the frequency change rate, * is the active power, P is the active power measurement data, is the active power measured by PMU, P N is the rated power of the synchronous generator, which is determined according to the rated power of the synchronous generator set;

[0063] Get the evaluation period;

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

[0065] The frequency deviation value is obtained 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] The evaluation time is obtained according to the frequency deviation value being equal to the frequency control dead zone; the evaluation time is the starting time of the evaluation period; the formula for obtaining the evaluation time is:

[0068] |Δf(t0)|=|f(t0)-f0|=Δfdead;

[0069] Where Δf(t0) is the frequency deviation value at time t0, t0 is the evaluation time, f(t0) is the frequency of the synchronous generator grid connection point at time t0, f0 is the nominal frequency of the synchronous generator grid connection point, Δf dead It 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] An active average value expression is constructed based on the evaluation time; the active average value is the active power average value of the synchronous generator grid-connected point before the evaluation time; the active average value is the 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 time, preferably, further, the preset time is 1 to 3s, and the preset sampling time interval is 10 to 50ms; more preferably, the preset time is 1s, the preset sampling time interval is 20ms, and the active average value is:

[0072]

[0073] Where P0 is the average active power, that is, the average active power of the synchronous generator grid-connected point sampled at the preset sampling time interval within the preset time before the evaluation moment, n is the preset time, i is the sampling sequence number, T s is the preset sampling time interval;

[0074] The active power variation expression is constructed based on the active power average value expression; the active power variation is the variation of the frequency modulation active power of the synchronous generator grid connection point relative to the active power average value; the active power variation expression is:

[0075] ΔP(t)=P(t)-P0;

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

[0077] Obtaining a preset value H of the inertia time constant of the synchronous generator;

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

[0079]

[0080] The theoretical frequency curve is obtained by inverse deduction based on the frequency expression;

[0081] Perform time-scale correction on the measured data according to the theoretical frequency curve;

[0082] The evaluation function is obtained by 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; the evaluation function is:

[0083]

[0084] In the formula, H P is the estimated value of the inertia time constant of the synchronous generator, ΔP * is the per unit value of active power change, is the per unit value of the total active power change from time t0 to time t1, where t0 is the evaluation time and t1 is the evaluation period. is the per-unit value of the frequency change from time t0 to time t1, f * is the frequency per unit value.

[0085] Based on the average window integration, the evaluation function is calculated according to the time-scale corrected measurement data to obtain the inertia time constant evaluation value.

[0086] Based on the average window integral, the steps to calculate the evaluation function and obtain the evaluation value of the inertial time constant according to the time-scale corrected measurement data are as follows:

[0087] The evaluation function is calculated according to the numerical integration formula, and the calculation result is output when the calculation result converges, and the inertia time constant evaluation value is obtained according to the calculation result.

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

[0089] Data processing unit:

[0090] Used to obtain the nominal frequency and measurement data of the synchronous generator grid connection point and transmit them to the calculation unit;

[0091] Used to obtain the evaluation period and transmit it to the computing unit;

[0092] Used to obtain the frequency control dead zone of the power system where the synchronous generator is located and transmit it to the calculation unit;

[0093] Used to obtain a preset value of the inertia time constant of the synchronous generator and transmit it to the modeling unit;

[0094] Used to obtain the theoretical frequency curve based on the frequency expression;

[0095] Used to perform time-scale correction on the measured data according to the theoretical frequency curve and transmit it to the calculation unit;

[0096] Computational Unit:

[0097] Used to obtain frequency deviation value according to nominal frequency and frequency;

[0098] Used to obtain the evaluation time according to the frequency deviation value being equal to the frequency control dead zone and transmit it to the modeling unit;

[0099] Used to calculate the evaluation function based on the average window integration and the measured data after time scale correction to obtain the evaluation value of the inertial time constant;

[0100] Modeling unit:

[0101] Used to construct an expression for the average value of active power based on the evaluation moment;

[0102] Used to construct the active power change expression based on the active power average value expression;

[0103] Used to construct a frequency expression based on the evaluation period, the active power change and the preset value of the inertia time constant and transmit it to the data processing unit;

[0104] An evaluation function is obtained by replacing a preset value of the inertia time constant in the frequency expression with an evaluation value of the inertia time constant of the synchronous generator and transmitted to a calculation unit.

[0105] Further, the computing unit includes a first computing module and a second computing module;

[0106] First calculation module:

[0107] Used to obtain frequency deviation value according to nominal frequency and frequency;

[0108] Used to obtain the evaluation time according to the frequency deviation value being equal to the frequency control dead zone and transmit it to the modeling unit;

[0109] Second calculation module:

[0110] It is used to calculate the evaluation function based on the average window integration and the time-scale corrected measurement data to obtain the inertia time constant evaluation value.

[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 evaluation function based on the average window integral is calculated by the second calculation module, which can functionally divide the calculation unit and improve the calculation rate.

[0112] Calculation example

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

[0114] Depend on Figure 3 It can be seen that the present invention performs time-scale correction on the frequency data to align the theoretical frequency curve with the active power measurement data, that is, the measurement data is time-scaled according to the theoretical frequency curve, which can prove that the frequency expression proposed in the present disclosure can calculate the inertia time constant more accurately. Figure 4 It can be seen that, by using the evaluation method proposed in the present disclosure, the synchronous generator frequency, frequency change rate and active power can be analyzed, and the inertia time constant of the synchronous generator can be extracted using the measured data.

[0115] It can be seen from this example that the evaluation method proposed in the present invention can reasonably and accurately evaluate the inertia time constant of the synchronous generator. According to the frequency, frequency change rate and active power data collected at the synchronous generator grid connection point, the measured data can be corrected using the method proposed in the present invention to evaluate the inertia time constant of the synchronous generator.

[0116] Therefore, the present invention adopts the above-mentioned data-driven synchronous generator inertia time constant evaluation method, which can be based on the measurement data of the PMU at the synchronous generator grid connection point. On the basis of correcting the measurement data, the size of the synchronous generator inertia time constant can be determined using the disturbed data. Research on the synchronous generator inertia time constant evaluation method has important guiding significance for the evaluation of the real frequency support capacity of new energy stations.

[0117] 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 data-driven synchronous generator inertia time constant evaluation method, characterized in that: The following steps are involved: Obtaining the nominal frequency and measurement data of the synchronous generator grid connection point; the measurement data includes frequency and active power; Get the evaluation period; Obtaining a frequency control dead zone of the power system where the synchronous generator is located; Obtaining a frequency deviation value according to the nominal frequency and the frequency; Obtaining an evaluation time according to the frequency deviation value being equal to the frequency control dead zone; the evaluation time is the starting time of the evaluation period; An active power average value expression is constructed based on the evaluation time; the active power average value is the active power average value of the synchronous generator grid connection point before the evaluation time; Constructing an active power variation expression based on the active power average value expression; The active power variation is the variation of the frequency-modulated active power of the synchronous generator grid connection point relative to the active power average value; Obtaining a preset value of the inertia time constant of a synchronous generator; Constructing a frequency expression based on the evaluation period, the active power change and the preset value of the inertia time constant; The frequency expression is the relationship between the frequency at the end of the evaluation period and the frequency at the evaluation moment; Obtaining a theoretical frequency curve by inverse deduction according to the frequency expression; Performing time-scale correction on the measurement data according to the theoretical frequency curve; Replacing the preset value of the inertia time constant in the frequency expression with an estimated value of the inertia time constant of the synchronous generator to obtain an evaluation function; The inertia time constant evaluation value is obtained by calculating the evaluation function based on the measured data after the time scale correction based on the average window integration.

2. The method for evaluating the inertia time constant of a synchronous generator based on data drive according to claim 1, characterized in that: The frequency deviation value is the absolute value of the difference between the nominal frequency and the frequency.

3. The method for evaluating the inertia time constant of a synchronous generator based on data drive according to claim 2, characterized in that: The active average value is the 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.

4. The method for evaluating the inertia time constant of a synchronous generator based on data drive 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 method for evaluating the inertia time constant of a synchronous generator based on data drive according to claim 3, characterized in that: The frequency expression is a relationship expression between the frequency per unit value, the active power change per unit value and the preset value of the inertia time constant.

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

7. The method for evaluating the inertia time constant of a synchronous generator based on data drive according to claim 1, characterized in that: When the evaluation function is calculated according to the measurement data corrected with the time scale based on the average window integration, the calculation result is output when the calculation result converges, and the inertia time constant evaluation value is obtained according to the calculation result.

8. The method for evaluating the inertia time constant of a synchronous generator based on data drive according to claim 1, characterized in that: A PMU is installed at the grid-connected point of the synchronous generator, and the measurement data is obtained according to the PMU.

9. A device for implementing the data-driven synchronous generator inertia time constant estimation method according to any one of claims 1 to 8, characterized in that: It includes a data processing unit, a computing unit and a modeling unit; The data processing unit: for obtaining the nominal frequency and measurement data of the synchronous generator grid connection point and transmitting them to the calculation unit; Used to obtain 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 calculation unit; Used to obtain a preset value of the inertia time constant of the synchronous generator and transmit it to the modeling unit; Used to obtain a theoretical frequency curve by inverse deduction according to the frequency expression; Used to perform time-scale correction on the measurement data according to the theoretical frequency curve and transmit the time-scale correction to the calculation unit; The computing unit: Used to obtain a frequency deviation value according to the nominal frequency and the frequency; Used to obtain an evaluation time according to the frequency deviation value being equal to the frequency control dead zone and transmit the evaluation time to the modeling unit; for calculating the evaluation function to obtain the inertia time constant evaluation value based on the measured data corrected by the time scale based on the average window integration; The modeling unit: for constructing an active power average value expression based on the evaluation time; Used to construct an active power variation expression based on the active power average value expression; Used to construct a frequency expression based on the evaluation period, the active power change and the preset value of the inertia time constant and transmit the frequency expression to the data processing unit; An evaluation function is obtained by replacing the preset value of the inertia time constant in the frequency expression with an evaluation value of the inertia time constant of the synchronous generator and transmitting the evaluation function to the calculation unit.

10. The device according to claim 9, characterized in that The computing unit includes a first computing module and a second computing module; The first calculation module: Used to obtain a frequency deviation value according to the nominal frequency and the frequency; Used to obtain an evaluation time according to the frequency deviation value being equal to the frequency control dead zone and transmit the evaluation time to the modeling unit; The second calculation module: The method is used for calculating the evaluation function based on the average window integration and the measured data after the time scale correction to obtain the inertia time constant evaluation value.

Images