Method and device for measuring flywheel torque of rotating parts of pumped storage unit

Abstract

The embodiments of this specification provide a method and device for measuring the flywheel torque of the rotating parts of a pumped storage unit, including: during the automatic shutdown process of the unit in power generation phase adjustment or pumping phase adjustment conditions, obtaining the active power, generator outlet circuit breaker state and speed signal within a predetermined measurement time from the shutdown time point; determining the circuit breaker opening time point according to the generator outlet circuit breaker state; calculating the active power average value and the speed average value respectively according to the active power and speed signal within the first time period before the opening time point; determining the speed change rate according to the speed signal within the second time period after the opening time point; determining the flywheel torque according to the active power average value, the speed average value, the speed change rate and the preset stator core loss. The method of this specification can improve the measurement accuracy, and can complete the measurement of the flywheel torque during conventional commissioning tests or normal automatic shutdown of the unit in phase adjustment conditions.

Description

Technical Field

[0001] One or more embodiments of the present specification relate to the field of pumped storage technology, and in particular, to a method and device for measuring the flywheel torque of a rotating component of a pumped storage unit. Background Art

[0002] Pumped storage units require fast start-up and frequent switching of operating conditions, so they have high requirements for the flywheel torque of rotating parts. If the flywheel torque is too small, the speed of the unit will rise rapidly during load shedding, and mechanical parts will be easily damaged; if the flywheel torque is too large, the mechanical inertia will be large, and the start-up and adjustment time of the unit will be long. In the type test of the unit, the flywheel torque needs to be measured to verify whether the actual value of the flywheel torque meets the design requirements. However, the existing measurement methods not only have test risks, but also have low measurement accuracy. Summary of the invention

[0003] In view of this, an object of one or more embodiments of the present specification is to provide a method and device for measuring the flywheel torque of a rotating component of a pumped-storage unit.

[0004] Based on the above purpose, one or more embodiments of this specification provide a method for measuring the flywheel torque of a rotating component of a pumped storage unit, including:

[0005] During the automatic shutdown process of the unit under power generation phase adjustment or water pumping phase adjustment conditions, the active power, generator output circuit breaker status and speed signal within the predetermined measurement time starting from the shutdown time point are obtained;

[0006] Determine the opening time of the circuit breaker according to the state of the generator output circuit breaker;

[0007] Calculating the average active power and the average speed respectively according to the active power and speed signals in a first time period before the opening time point;

[0008] Determine the speed change rate according to the speed signal within a second time period after the opening time point; wherein the first time period and the second time period are both within the measurement time;

[0009] The flywheel torque is determined according to the active power average value, the rotational speed average value, the rotational speed change rate and the preset stator core loss.

[0010] Optionally, determining the speed change rate according to the speed signal within a second time period after the opening time point includes:

[0011] determining a plurality of rotation speed signals within the second time period;

[0012] Fitting several speed signals to obtain a speed signal fitting straight line;

[0013] The slope of the speed signal fitting straight line is taken as the speed change rate.

[0014] Optionally, the flywheel torque is determined according to the average active power value, the average speed value, the speed change rate and a preset stator core loss, including:

[0015] The moment of inertia is calculated based on the average active power, average speed, speed change rate and stator core loss:

[0016] The flywheel torque is calculated based on the rotational inertia.

[0017] Optionally, calculating the average active power value according to the active power in a first time period before the opening time point includes:

[0018] The active power average value is calculated according to the absolute value of the active power within the first time period.

[0019] Optionally, when the speed signal is a percentage of the rated speed, the method for calculating the moment of inertia is:

[0020]

[0021] Wherein, P0 is the average active power, n0 is the average speed, n N is the rated speed, P Fe is the stator core loss, and k is the speed change rate.

[0022] Optionally, when the speed signal is speed per minute, the method for calculating the moment of inertia is:

[0023]

[0024] Wherein, P0 is the average active power, n0 is the average speed, P Fe is the stator core loss, and k is the speed change rate.

[0025] Optionally, the first time period is an integer multiple of the rotation period of the rotating component.

[0026] Optionally, the second time period ranges from 6 to 10 seconds.

[0027] The embodiment of this specification also provides a device for measuring the flywheel torque of the rotating parts of a pumped storage unit, comprising:

[0028] An acquisition module is used to acquire the active power, generator output circuit breaker status and speed signal within a predetermined measurement time from the shutdown time point during the automatic shutdown process of the unit in power generation phase adjustment or pumping phase adjustment conditions;

[0029] A time point determination module, used to determine the opening time point of the circuit breaker according to the state of the generator outlet circuit breaker;

[0030] A first calculation module, used to calculate the average active power and the average speed respectively according to the active power and speed signals within a first time period before the opening time point;

[0031] A speed change rate determination module, used to determine the speed change rate according to the speed signal within a second time period after the opening time point; wherein the first time period and the second time period are both within the measurement time;

[0032] The second calculation module is used to determine the flywheel torque according to the average active power, the average speed, the speed change rate and the preset stator core loss.

[0033] Optionally, the speed change rate determination module is used to determine a number of speed signals within the second time period, fit the several speed signals to obtain a speed signal fitting line, and use the slope of the speed signal fitting line as the speed change rate.

[0034] From the above, it can be seen that the method and device for measuring the flywheel torque of the rotating parts of the pumped storage unit provided in one or more embodiments of this specification, in the normal automatic shutdown process of the conventional commissioning test or the unit phase adjustment condition (power generation phase adjustment or pumping phase adjustment), obtains the active power, generator output circuit breaker status and speed signal within the predetermined measurement time from the shutdown time point; determines the circuit breaker opening time point according to the generator output circuit breaker status; calculates the active power average value and the speed average value respectively according to the active power and speed signal within the first time period before the opening time point; determines the speed change rate according to the speed signal within the second time period after the opening time point; determines the flywheel torque according to the active power average value, the speed average value, the speed change rate and the preset stator core loss. According to the method of this specification, there is no need to carry out a separate flywheel torque measurement test, which saves test costs and can improve measurement accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate one or more embodiments of the present specification or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only one or more embodiments of the present specification. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0036] Figure 1It is a schematic diagram of a speed variation curve in the process of measuring flywheel torque in the related art;

[0037] Figure 2 A schematic diagram of a method flow of one or more embodiments of this specification;

[0038] Figure 3 A schematic diagram of active power variation according to one or more embodiments of this specification;

[0039] Figure 4 A schematic diagram of GCB state changes according to one or more embodiments of this specification;

[0040] Figure 5 A schematic diagram of the rotation speed change of one or more embodiments of this specification;

[0041] Figure 6 A schematic diagram of a speed signal fitting straight line obtained by fitting in one or more embodiments of this specification;

[0042] Figure 7 A block diagram of the device structure of one or more embodiments of this specification. DETAILED DESCRIPTION

[0043] In order to make the objectives, technical solutions and advantages of the present disclosure more clearly understood, the present disclosure is further described in detail below in combination with specific embodiments and with reference to the accompanying drawings.

[0044] It should be noted that, unless otherwise defined, the technical terms or scientific terms used in one or more embodiments of this specification should be understood by people with ordinary skills in the field to which this disclosure belongs. The "first", "second" and similar words used in one or more embodiments of this specification do not indicate any order, quantity or importance, but are only used to distinguish different components. "Include" or "comprise" and similar words mean that the elements or objects appearing before the word cover the elements or objects listed after the word and their equivalents, without excluding other elements or objects. "Connect" or "connected" and similar words are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0045] As mentioned in the background technology section, flywheel torque is an important indicator for measuring the performance of pumped storage units. The measurement method recommended by relevant standards (for example, GB / T 1029 "Three-phase synchronous motor test method") generally proceeds as follows: after the unit has been running in the power generation direction with a certain load (generally 0.1 to 0.2 times the rated load) for a period of time, it is suddenly disconnected from the power grid to shed the load, and the speed change curve of the rotating parts changing with time is measured. The speed value corresponding to the load shedding is determined on the speed change curve, and the tangent slope at the speed change curve corresponding to the speed value is determined as the angular velocity change rate. The flywheel torque is calculated based on the angular velocity change rate combined with the angular momentum theorem. Among them, the angular momentum theorem shows:

[0046]

[0047] Where J is the moment of inertia, in kg·m 2 ;ω is the angular velocity of the rotating part, in radians per second (rad / s); M T M is the mechanical torque acting on the rotating parts, measured in Newton-meter (N·m); E is the electromagnetic torque acting on the rotating part, in N·m; P T P is the mechanical power acting on the rotating parts, measured in watts (W); E It is the electromagnetic power acting on the rotating parts, measured in W.

[0048] Before the unit is unloaded, the speed of the rotating parts is stable and the mechanical power P T and electromagnetic power P E Equal; after load shedding, electromagnetic power P E The speed drops to 0 in a very short time when the unit is disconnected. At this time, the guide vane opening remains unchanged. The speed change curve (such as Figure 1 As shown), the tangent slope k at the speed value when the load is dumped on the curve is the angular velocity change rate, and the mechanical power P T In a very short time after disconnection, it is still equal to the electromagnetic power P before load shedding. E , then the moment of inertia J can be calculated and expressed as:

[0049]

[0050] Among them, ω S It is the angular velocity of the rotating parts when the load is dropped, in rad / s.

[0051] After determining the moment of inertia, the flywheel torque GD can be obtained 2 , expressed as:

[0052] GD 2 =4J (3)

[0053] The test requirements that the above measurement method needs to meet are that the speed governor is shut down before the test, and the generator keeps the excitation unchanged during the test. However, in order to ensure the safety of the unit and prevent overspeed and overvoltage, conventional load shedding tests require the speed governor to be put into operation, and the excitation system is shut down after the load shedding. Therefore, the problems with the above measurement method are: it cannot be combined with conventional tests, and it is necessary to carry out special tests to measure the flywheel torque, which adds additional test items, test duration and test risks; on the other hand, since the stator core loss is not considered, the mechanical power and electromagnetic power are not actually equal, and there is a deviation in the calculation result; moreover, the measured speed signal has noise, and the obtained speed change curve is not a smooth curve, which makes it difficult to accurately determine the angular velocity change rate, increasing the measurement error.

[0054] In view of the above reasons, the embodiment of this specification provides a method for measuring the flywheel torque of the rotating parts of a pumped storage unit. After the unit is shut down normally under power generation phase adjustment or pumping phase adjustment conditions, the active power, generator output circuit breaker status and speed signal within a certain period of time are obtained, and the average active power and speed before the circuit breaker is opened are calculated. The speed change rate is determined according to the speed signal within a certain period of time after the circuit breaker is opened. After that, the flywheel torque is determined according to the average active power, the average speed, the speed change rate and the stator core loss. The measurement method of this specification can complete the measurement during the automatic shutdown or routine test process of the unit under normal operation phase adjustment conditions, without the need for special tests, and thus will not add additional test items, test duration and test risks. Moreover, the calculation process takes into account the stator core loss, and the speed change rate is determined by fitting, which can reduce errors and improve the accuracy of the measurement results.

[0055] The technical solution of the present application is further described in detail below through the accompanying drawings and specific embodiments.

[0056] like Figure 2 As shown, the embodiment of this specification provides a method for measuring the flywheel torque of the rotating parts of a pumped storage unit, comprising:

[0057] S201: Obtaining active power, generator output circuit breaker status and speed signal within a predetermined measurement time from the shutdown time point under the unit phase adjustment condition;

[0058] In this embodiment, the flywheel torque can be measured during the automatic shutdown process of the unit in the normal operation phase adjustment condition or in the normal commissioning test. During the normal shutdown process of the unit in the power generation phase adjustment condition or the pumping phase adjustment condition, the unit status monitoring system collects and obtains the active power, the generator output circuit breaker status (GCB status) and the speed signal within the predetermined measurement time for subsequent data analysis and calculation.

[0059] Combination Figure 3 , 4 As shown in Figure 5, taking the phase-shifting condition of power generation as an example, when the unit is operating under the phase-shifting condition, the pump-turbine rotates in the air and consumes less active power; it automatically shuts down after stable operation for a certain period of time (for example, 30 minutes) under this condition. Starting from the shutdown time point, according to the acquired active power, the state of the generator output circuit breaker and the speed signal, the active power change curve, the generator output circuit breaker state change line, and the speed change curve of the speed signal over time are drawn respectively. During the shutdown process, the GCB is opened. After the opening, the active power returns to zero, the torque drops to zero, and the unit phase-shifting water pressure system performs exhaust and water return operation. During the water return process, the water level in the tailwater pipe rises. Before the water level rises to the lower part of the pump-turbine runner, the pump-turbine and the generator motor rotate in the air. When the speed drops slightly from the average speed before the GCB is opened, it can be approximately considered that the combined resistance torque generated by wind resistance and mechanical friction is a constant value (recorded as T0), and the unit speed decreases uniformly (such as Figure 5 The approximate straight line portion enclosed by the ellipse during the change of the medium speed). When the water enters the runner, the resistance torque increases, and at the same time, under the action of the electric brake, the speed of the unit drops rapidly.

[0060] S202: Determine the opening time of the circuit breaker according to the state of the generator output circuit breaker;

[0061] S203: Calculating the average active power and the average speed respectively according to the active power and speed signals in the first time period before the tripping time point;

[0062] S204: determining the speed change rate according to the speed signal within a second time period after the gate opening time point; wherein the first time period and the second time period are both within the measurement time;

[0063] In this embodiment, after the unit is shut down, the circuit breaker is controlled to open, and the opening time point of the circuit breaker after the shutdown is determined according to the obtained generator outlet circuit breaker state, and the predetermined measurement time is divided into a first time period and a second time period based on the opening time point. Among them, the first time period is a certain time period before the opening time point, and the active power average value and the speed average value in the first time period are calculated according to the active power and speed signal obtained in the first time period; the second time period is a certain time period after the opening time point, and the speed change rate is determined according to the speed signal obtained in the second time period.

[0064] In some methods, under phase modulation conditions, the generator does not generate active power, but absorbs active power from the power grid. The pump turbine rotates in the air, which consumes part of the active power. When the average active power is calculated in the first time period, it is calculated based on the absolute value of the active power without considering the positive or negative sign of the active power. Among them, the active power with a negative sign indicates the absorbed active power, and the active power with a positive sign indicates the emitted active power.

[0065] In some embodiments, the first time period is an integer multiple of the rotation period of the rotating component. Under the phase adjustment condition of the unit, it can be considered that the active power fluctuates at the average active power value. At the average active power value, the dynamic torque and the resistance torque reach a balance. In order to obtain an accurate average active power value, a duration that is an integer multiple of the rotation period can be selected.

[0066] In some methods, as the speed decreases, the wind resistance and friction torque will change, and thus the speed change rate will change. When the speed decreases by a small amount, the speed change rate can be approximately considered to be consistent. If a shorter time period is selected, the amount of speed signal data involved in the speed signal linear fitting is smaller, which may increase the fitting error, and the determined speed change rate error is larger, affecting the accuracy of the flywheel torque measurement results. Therefore, in order to ensure the measurement accuracy, the time range of the second time period is selected to be 6-10 seconds.

[0067] In some embodiments, a method for determining the speed change rate according to the speed signal within the second time period is:

[0068] determining a plurality of speed signals within a second time period;

[0069] Fitting several speed signals to obtain a speed signal fitting straight line;

[0070] The slope of the speed signal fitting straight line is taken as the speed change rate.

[0071] like Figure 6 As shown, the speed signals actually obtained are different, the speed signals have the same changing trends, and the several speed signals obtained in the second time period are not on a straight line, and it is difficult to accurately determine the speed change rate based on one of the speed signals. Therefore, in this embodiment, fitting is performed based on several speed signals within the second time period to obtain a speed signal fitting line, and the slope of the speed signal fitting line is used as the speed change rate, which can more accurately characterize the speed change trend. Optionally, noise reduction processing is first performed based on the several speed signals obtained to remove the noise signal therein, and then based on the speed signal after noise reduction, the least squares method is used for linear fitting to obtain the speed signal fitting line. The specific noise reduction method and fitting method are not limited.

[0072] S205: Determine the flywheel torque according to the average active power, the average speed, the speed change rate and the preset stator core loss.

[0073] In this embodiment, within the measurement time during the normal shutdown process under the phase adjustment condition of the unit, after determining the average value of active power, the average value of speed, the speed change rate and the stator core loss, the flywheel torque is calculated based on the angular momentum theorem. Further, the moment of inertia is first calculated based on the average value of active power, the average value of speed, the speed change rate and the stator core loss: and then the flywheel torque is calculated based on the moment of inertia.

[0074] Specifically: Under the phase adjustment condition, the unit absorbs active power from the grid. Except for the stator core loss, the remaining active power is used to generate electromagnetic torque. Under this condition, when the unit is running stably, the electromagnetic torque is equal to the combined resistance torque. After the shutdown operation GCB is opened, the speed drops slightly in the second time period, the electromagnetic torque is zero, and the combined resistance torque is approximately unchanged. Its size can be regarded as P0-P Fe , according to the angular momentum theorem:

[0075]

[0076] available:

[0077]

[0078] Among them, P0 is the average active power, P Fe is the stator core loss, ω0 is the angular velocity of the rotating parts before the circuit breaker is opened, in rad / s.

[0079] When the measured speed signal is a percentage of the rated speed, the calculation method of the angular velocity ω0 before the circuit breaker is opened is:

[0080]

[0081] Among them, n N is the rated speed, in rad / s, and n0 is the average speed.

[0082] The rate of change of angular velocity in radians is calculated as:

[0083]

[0084] Wherein, k is the measured speed change rate.

[0085] Substituting formula (6) and (7) into formula (5), the moment of inertia can be obtained as:

[0086]

[0087] When the measured speed signal is in revolutions per minute, the calculation method of the angular velocity ω0 before the circuit breaker is opened is:

[0088]

[0089] The rate of change of angular velocity in radians is calculated as:

[0090]

[0091] Substituting formula (9) and (10) into formula (5), the moment of inertia can be obtained as:

[0092]

[0093] After the moment of inertia is calculated according to formula (8) or (11), the flywheel torque can be calculated according to formula (3).

[0094] In some application scenarios, the rated speed n of a pumped storage unit N The speed is 500 rpm, and the design value of the flywheel torque of the generator motor is 3600 T·m 2 The design value of the pump turbine flywheel torque is 271T·m 2 , then the design value of the flywheel torque of the rotating parts of the unit is 3871T·m 2 The stator core loss of the generator motor is 582kW. The unit automatically shuts down after running stably for 30 minutes under the phase modulation condition. The active power, generator output circuit breaker status and speed signal are obtained during the shutdown process. Figure 3-5 As shown, a corresponding change curve is drawn according to the acquired active power, generator outlet circuit breaker state and speed signal, wherein the speed signal is expressed as a percentage of the rated speed.

[0095] Through analysis, 30 rotation cycles (for example, 3.6s) are selected from the opening time point of the circuit breaker as the first time period. According to the active power in the first time period, the average active power is calculated, and P0 = 3961kW can be obtained. According to the speed signal in the first time period, the average speed is calculated, and n0 = 99.96 can be obtained. From the opening time point, a period of 8 seconds is selected as the second time period, and all speed signals in the second time period are obtained. Figure 6 As shown, the linear least square method is used to fit all the speed signals in the second time period to obtain a speed signal fitting straight line (such as Figure 6 The speed signal fitting line has a slope k = -0.129193, which is the speed change rate.

[0096] Then, the average active power, average speed, stator core loss, and speed change rate are substituted into formula (8) to calculate the moment of inertia:

[0097]

[0098] Calculate the flywheel torque based on the moment of inertia:

[0099] GD 2 =954.4×4=3817.6T·m 2 (13)

[0100] That is, the actual value of the measured flywheel torque is 3817.6 T·m 2 , compared with the design value of 3871T·m 2 The deviation is 53.4T·m 2 The measurement error is -1.4%, while the measurement error of the relevant standard is generally about 6%. It can be seen that the measurement method provided in this embodiment improves the measurement accuracy.

[0101] The method for measuring the flywheel torque of the rotating parts of the pumped storage unit provided in the embodiment of this specification, during the normal shutdown process of the unit under the phase-shifting or pumping phase-shifting conditions, by obtaining the active power and speed signal within a certain measurement time, the average active power and the average speed are determined, and the speed change rate is determined according to the speed signal within a certain time after the GCB is opened, and the flywheel torque is calculated based on the angular momentum theorem according to the average active power, the average speed, and the speed change rate, while considering the stator core loss. Compared with the existing measurement method, the flywheel torque can be measured during the routine commissioning test of the unit or the automatic shutdown process of the daily operation phase-shifting condition, without the need to perform a separate flywheel torque measurement test, thereby saving time and labor costs and avoiding test risks. At the same time, considering the stator core loss, the speed change rate is obtained by fitting a straight line, which can improve the measurement accuracy. For the pumped storage industry in a period of rapid development, the flywheel torque measurement method of this application is technologically advanced and can bring significant economic benefits.

[0102] like Figure 7 As shown, one or more embodiments of this specification also provide a device for measuring the flywheel torque of a rotating component of a pumped storage unit, comprising:

[0103] An acquisition module is used to acquire the active power, generator output circuit breaker status and speed signal within a predetermined measurement time from the shutdown time point during the automatic shutdown process of the unit in power generation phase adjustment or pumping phase adjustment conditions;

[0104] A time point determination module, used to determine the opening time point of the circuit breaker according to the state of the generator outlet circuit breaker;

[0105] A first calculation module, used to calculate the average active power and the average speed respectively according to the active power and speed signals within a first time period before the opening time point;

[0106] A speed change rate determination module, used to determine the speed change rate according to the speed signal within a second time period after the opening time point; wherein the first time period and the second time period are both within the measurement time;

[0107] The second calculation module is used to determine the flywheel torque according to the average active power, the average speed, the speed change rate and the preset stator core loss.

[0108] For the convenience of description, the above devices are described in terms of functions divided into various modules. Of course, when implementing one or more embodiments of this specification, the functions of each module can be implemented in the same or multiple software and / or hardware.

[0109] The apparatus of the above-mentioned embodiment is used to implement the corresponding method in the above-mentioned embodiment, and has the beneficial effects of the corresponding method embodiment, which will not be described in detail here.

[0110] Those skilled in the art should understand that the discussion of any of the above embodiments is merely illustrative and is not intended to imply that the scope of the present disclosure (including the claims) is limited to these examples. In line with the present disclosure, the technical features in the above embodiments or different embodiments may be combined, the steps may be implemented in any order, and there are many other variations of different aspects of one or more embodiments of the present specification as described above, which are not provided in detail for the sake of simplicity.

[0111] In addition, to simplify the description and discussion, and in order not to obscure one or more embodiments of the present specification, known power / ground connections to integrated circuit (IC) chips and other components may or may not be shown in the provided figures. In addition, devices may be shown in the form of block diagrams to avoid obscuring one or more embodiments of the present specification, and this also takes into account the fact that the details of the implementation of these block diagram devices are highly dependent on the platform on which one or more embodiments of the present specification will be implemented (i.e., these details should be fully within the scope of understanding of those skilled in the art). Where specific details (e.g., circuits) are set forth to describe exemplary embodiments of the present disclosure, it is apparent to those skilled in the art that one or more embodiments of the present specification may be implemented without these specific details or with variations in these specific details. Therefore, these descriptions should be considered illustrative rather than restrictive.

[0112] Although the present disclosure has been described in conjunction with specific embodiments of the present disclosure, many replacements, modifications and variations of these embodiments will be apparent to those skilled in the art from the foregoing description. For example, other memory architectures (e.g., dynamic RAM (DRAM)) may use the embodiments discussed.

[0113] One or more embodiments of this specification are intended to cover all such substitutions, modifications and variations that fall within the broad scope of the appended claims. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of one or more embodiments of this specification should be included in the scope of protection of this disclosure.

Claims

1. A method for measuring the flywheel torque of a rotating component of a pumped storage unit, characterized in that: include: During the automatic shutdown process of the unit under power generation phase adjustment or water pumping phase adjustment conditions, the active power, generator output circuit breaker status and speed signal within the predetermined measurement time starting from the shutdown time point are obtained; Determine the opening time of the circuit breaker according to the state of the generator output circuit breaker; Calculating the average active power and the average speed respectively according to the active power and speed signals in a first time period before the opening time point; Determine the speed change rate according to the speed signal within a second time period after the opening time point; wherein the first time period and the second time period are both within the measurement time; The flywheel torque is determined according to the active power average value, the rotational speed average value, the rotational speed change rate and the preset stator core loss.

2. The method according to claim 1, characterized in that Determining the speed change rate according to the speed signal within a second time period after the opening time point includes: determining a plurality of rotation speed signals within the second time period; Fitting several speed signals to obtain a speed signal fitting straight line; The slope of the speed signal fitting straight line is taken as the speed change rate.

3. The method according to claim 1 or 2, characterized in that: Determining the flywheel torque according to the active power average value, the speed average value, the speed change rate and the preset stator core loss includes: The moment of inertia is calculated based on the average active power, average speed, speed change rate and stator core loss: The flywheel torque is calculated based on the rotational inertia.

4. The method according to claim 1, characterized in that: Calculating the average active power according to the active power in a first time period before the opening time point includes: The active power average value is calculated according to the absolute value of the active power within the first time period.

5. The method according to claim 3, characterized in that: When the speed signal is a percentage of the rated speed, the method for calculating the moment of inertia is: Wherein, P0 is the average active power, n0 is the average speed, n N is the rated speed, P Fe is the stator core loss, and k is the speed change rate.

6. The method according to claim 3, characterized in that When the speed signal is speed per minute, the method for calculating the moment of inertia is: Wherein, P0 is the average active power, n0 is the average speed, P Fe is the stator core loss, and k is the speed change rate.

7. The method according to claim 1, characterized in that The first time period is an integer multiple of a rotation period of the rotating component.

8. The method according to claim 1, characterized in that The second time period ranges from 6 to 10 seconds.

9. A device for measuring the flywheel torque of a rotating part of a pumped storage unit, characterized in that: include: An acquisition module is used to acquire the active power, generator output circuit breaker status and speed signal within a predetermined measurement time from the shutdown time point during the automatic shutdown process of the unit in power generation phase adjustment or pumping phase adjustment conditions; A time point determination module, used to determine the opening time point of the circuit breaker according to the state of the generator outlet circuit breaker; A first calculation module, used to calculate the average active power and the average speed respectively according to the active power and speed signals within a first time period before the opening time point; A speed change rate determination module, used to determine the speed change rate according to the speed signal within a second time period after the opening time point; wherein the first time period and the second time period are both within the measurement time; The second calculation module is used to determine the flywheel torque according to the average active power, the average speed, the speed change rate and the preset stator core loss.

10. The device according to claim 9, characterized in that The speed change rate determination module is used to determine a plurality of speed signals within the second time period, fit the plurality of speed signals to obtain a speed signal fitting straight line, and use the slope of the speed signal fitting straight line as the speed change rate.

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