Method, device and equipment for suppressing ultra-low frequency oscillation of power system and storage medium

Abstract

Embodiments of the present application disclose a power system ultra-low frequency oscillation suppression method, device, equipment and storage medium, the method comprises: acquiring the frequency signal data of the power system and the rotor speed of each wind turbine generator collected by the synchronous phasor measurement device; using the oscillation frequency and the rotor speed of each wind turbine generator to determine whether each wind turbine generator enters the system frequency ultra-low frequency oscillation suppression mode; if any wind turbine generator enters the system frequency ultra-low frequency oscillation suppression mode, then correct the active output reference power of any target wind turbine generator entering the system frequency ultra-low frequency oscillation suppression mode according to the oscillation frequency and amplitude, and realize the suppression of the system frequency ultra-low frequency oscillation. The present application fully considers the flexible control potential of wind power frequency, can realize the active participation of wind power in system frequency ultra-low frequency oscillation suppression, improve system damping and reduce system ultra-low frequency oscillation risk, fully tap the potential of wind power frequency stability control and improve system operation stability.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of power system frequency control, and in particular to a power system ultra-low frequency oscillation suppression method, device, equipment and storage medium. BACKGROUND

[0002] With the development and construction of power grid in China, operation modes such as DC sending end island and inter-regional power grid asynchronous interconnection appear in the power system, and corresponding actual power grid operation has occurred several times of power system ultra-low frequency oscillation events, which are characterized by an oscillation frequency lower than 0.1 Hz, and the main reason is that the small disturbance frequency stability problem caused by the governor control in the power grid dominated by hydropower occurs, which is one of the main factors threatening the safe and stable operation of the power grid. With the increasing proportion of wind power access, the potential of flexible adjustment needs to be further tapped, and the weakly damped system is prone to frequency stability and oscillation problems, and wind power frequency control is an important measure to improve system operation reliability. The traditional wind power frequency control mainly deals with frequency instability problems, and the control strategy is relatively aggressive, so it cannot deal with the system ultra-low frequency oscillation with a longer time scale of relative frequency instability. SUMMARY

[0003] The main purpose of the present application is to provide a power system ultra-low frequency oscillation suppression method, device, equipment and storage medium, which can solve the lack of effective suppression of ultra-low frequency oscillation in the prior art.

[0004] To achieve the above-mentioned purpose, the first aspect of the present application provides a power system ultra-low frequency oscillation suppression method, which is applied to a wind farm main control system, and the method comprises the following steps:

[0005] Obtaining frequency signal data of the power system and rotor speeds of each wind turbine generator unit collected by a synchronous phasor measurement device, wherein the frequency signal data at least includes an oscillation frequency and an amplitude of the power system;

[0006] Determining whether each wind turbine generator unit enters a system frequency ultra-low frequency oscillation suppression mode by using the oscillation frequency and the rotor speeds of each wind turbine generator unit;

[0007] If any of the wind turbine generator units enters the system frequency ultra-low frequency oscillation suppression mode, correcting active output reference power of a target wind turbine generator unit according to the oscillation frequency and the amplitude to realize suppression of the system frequency ultra-low frequency oscillation, wherein the target wind turbine generator unit is any wind turbine generator unit entering the system frequency ultra-low frequency oscillation suppression mode.

[0008] In a feasible implementation manner, the step of determining whether each wind turbine generator unit enters the system frequency ultra-low frequency oscillation suppression mode by using the oscillation frequency and the rotor speeds of each wind turbine generator unit comprises:

[0009] The oscillation frequency and a preset frequency threshold are used to determine an oscillation type of the power system, the oscillation type at least including ultra-low frequency oscillation.

[0010] When the oscillation type of the power system is ultra-low frequency oscillation, the rotor speed of each wind turbine and the maximum power tracking mode lower limit speed are used to determine whether the wind turbine enters the system frequency ultra-low frequency oscillation suppression mode.

[0011] When the rotor speed of any wind turbine is greater than the maximum power tracking mode lower limit speed, it is determined that the corresponding wind turbine enters the system frequency ultra-low frequency oscillation suppression mode.

[0012] In a possible implementation, the method for suppressing system frequency ultra-low frequency oscillation by correcting the active output reference power of the target wind turbine according to the oscillation frequency and amplitude includes:

[0013] The maximum releasable rotor kinetic energy of the target wind turbine is determined by using the rotor speed of the target wind turbine and the maximum power tracking mode lower limit speed.

[0014] The current mechanical power and mechanical output power of the target wind turbine are determined according to the rotor speed, operating wind speed and pitch angle of the target wind turbine.

[0015] The mechanical power change value of the target wind turbine is determined by using the mechanical output power and the current mechanical power.

[0016] The wind power ultra-low frequency oscillation suppression control parameter is determined according to the maximum releasable rotor kinetic energy, the mechanical power change value, the oscillation frequency and the amplitude.

[0017] The active output reference power of the target wind turbine is corrected by using the system frequency change, the wind power ultra-low frequency oscillation suppression control parameter and the reference power of the operating point of the target wind turbine before entering the system frequency ultra-low frequency oscillation suppression mode, so as to suppress the system frequency ultra-low frequency oscillation.

[0018] In a possible implementation, the maximum releasable rotor kinetic energy of the target wind turbine is determined by using the rotor speed of the target wind turbine and the maximum power tracking mode lower limit speed.

[0019]

[0020] In the formula, ΔE WT is the maximum releasable rotor kinetic energy, H WT is the inherent inertia time constant of the wind turbine, ω1 is the current operating rotor speed of the wind turbine, and ω0 is the maximum power tracking mode lower limit speed.

[0021] In an implementable manner, the current mechanical power and the mechanical output power of the target wind turbine are determined by using the rotor speed, the operating wind speed and the pitch angle of the target wind turbine, which comprises:

[0022]

[0023] wherein, ρ is the air density, C p is the wind energy capture efficiency coefficient; λ is the tip speed ratio, λ i is an intermediate variable, A is the blade wind energy capture area, ω is the rotor speed, v is the operating wind speed, β is the pitch angle, R is the wind turbine rotor radius, ω = ω1 gives the current wind turbine mechanical power P1, and ω = ω1 and β = 0 give the mechanical power output P2.

[0024] In an implementable manner, in a half cycle of the frequency change of the ultra-low frequency oscillation, the rotor kinetic energy contained in the target wind turbine is sufficient to continuously provide support for the active output reference power, and the wind power ultra-low frequency oscillation suppression control parameter is determined according to the maximum releasable rotor kinetic energy, the mechanical power change value, the oscillation frequency and the amplitude, which comprises:

[0025]

[0026] wherein, A0 is the amplitude of the system frequency oscillation, T is the oscillation period, K WT is the wind power ultra-low frequency oscillation suppression control parameter, ΔE WT is the maximum releasable rotor kinetic energy, and ΔP is the mechanical power change value.

[0027] In an implementable manner, the active output reference power of the target wind turbine is corrected by using the system frequency change, the wind power ultra-low frequency oscillation suppression control parameter and the reference power of the operating point of the target wind turbine before entering the system frequency ultra-low frequency oscillation suppression mode, which comprises:

[0028] P ref = P0 + K WT Δf

[0029] wherein, P ref is the active output reference power, P0 is the reference power of the operating point of the target wind turbine before entering the system frequency ultra-low frequency oscillation suppression mode, Δf is the system frequency change, and K WT is the wind power ultra-low frequency oscillation suppression control parameter.

[0030] To achieve the above-mentioned purposes, the second aspect of the present application provides a power system ultra-low frequency oscillation suppression device, which is applied to a wind farm main control system, and the device comprises:

[0031] The data acquisition module is used for acquiring frequency signal data of the power system collected by the synchronous phasor measurement device and rotor speeds of each wind turbine, and the frequency signal data at least includes an oscillation frequency and an amplitude of the power system.

[0032] The state determination module is used for determining whether each wind turbine enters the system frequency ultra-low frequency oscillation suppression mode by using the oscillation frequency and the rotor speeds of each wind turbine.

[0033] The frequency suppression module is used for correcting active output reference power of a target wind turbine according to the oscillation frequency and the amplitude if any wind turbine enters the system frequency ultra-low frequency oscillation suppression mode, so as to realize suppression of the system frequency ultra-low frequency oscillation, and the target wind turbine is any wind turbine entering the system frequency ultra-low frequency oscillation suppression mode.

[0034] To achieve the above object, the third aspect of the present application provides a computer readable storage medium, which stores a computer program, and the computer program is executed by a processor to make the processor execute the steps shown in the first aspect and any feasible implementation manner.

[0035] To achieve the above object, the fourth aspect of the present application provides a computer device, which includes a memory and a processor, and the memory stores a computer program, and the computer program is executed by the processor to make the processor execute the steps shown in the first aspect and any feasible implementation manner.

[0036] The embodiment of the present application has the following beneficial effects:

[0037] The present application provides a power system ultra-low frequency oscillation suppression method, which is applied to a wind farm main control system, and the method includes the following steps: acquiring frequency signal data of the power system collected by a synchronous phasor measurement device and rotor speeds of each wind turbine, and the frequency signal data at least includes an oscillation frequency and an amplitude of the power system; determining whether each wind turbine enters a system frequency ultra-low frequency oscillation suppression mode by using the oscillation frequency and the rotor speeds of each wind turbine; and correcting active output reference power of a target wind turbine according to the oscillation frequency and the amplitude if any wind turbine enters the system frequency ultra-low frequency oscillation suppression mode, so as to realize suppression of the system frequency ultra-low frequency oscillation, and the target wind turbine is any wind turbine entering the system frequency ultra-low frequency oscillation suppression mode. The present application fully considers flexible control potential of wind power frequency, can realize active participation of wind power in system frequency ultra-low frequency oscillation suppression, improves system damping and reduces system ultra-low frequency oscillation risk, and has far-reaching significance for fully tapping wind power frequency stability control potential and improving system operation stability. BRIEF DESCRIPTION OF DRAWINGS

[0038] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description only constitute some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained from these drawings without creative labor.

[0039] Wherein:

[0040] Figure 1 It is a flowchart of a power system ultra-low frequency oscillation suppression method in an embodiment of the present application.

[0041] Figure 2 It is another flowchart of a power system ultra-low frequency oscillation suppression method in an embodiment of the present application.

[0042] Figure 3 It is a structure block diagram of a power system ultra-low frequency oscillation suppression device in an embodiment of the present application.

[0043] Figure 4 It is a structure block diagram of a computer device in an embodiment of the present application. DETAILED DESCRIPTION

[0044] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments only constitute some embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0045] Please refer to Figure 1 , Figure 1 It is a flowchart of a power system ultra-low frequency oscillation suppression method in an embodiment of the present application, as shown in the method applied to a wind farm main control system, the method comprises the following steps: Figure 1

[0046] 101, acquiring frequency signal data of a power system and rotor speeds of each wind turbine generator collected by a synchronous phasor measurement device, the frequency signal data at least includes an oscillation frequency and an amplitude of the power system;

[0047] ​It should be noted that the present application can be executed by a wind farm master control system included in a power system, the wind farm master control system being used to control each wind turbine generator included in the power system. Further, the wind farm master control system can acquire the rotor speed of each wind turbine generator, and acquire frequency signal data of the power system collected by a synchronous phasor measurement device, the frequency signal data including but not limited to frequency information reflecting the operating state of the power system, and the frequency signal data at least including the frequency signal of the power system, the oscillation frequency and amplitude corresponding to the frequency signal. Wherein the synchronous phasor measurement device can transmit the acquired frequency signal of the power system and the oscillation frequency and amplitude corresponding to the frequency signal to the wind farm master control system in real time. Wherein the synchronous phasor measurement device (PMU: phasor measurement unit) is a phasor measurement unit constituted by using a global positioning system (GPS) second pulse as a synchronous clock. It can be used in the fields of dynamic monitoring, system protection, system analysis and prediction of the power system. It is an important equipment to ensure the safe operation of the power grid.

[0048] 102, using the oscillation frequency and the rotor speed of each wind turbine generator, determine whether each wind turbine generator enters the system frequency ultra-low frequency oscillation suppression mode;

[0049] In the embodiment of the present application, by using the oscillation frequency and the rotor speed of each wind turbine generator, it is determined whether each wind turbine generator enters the system frequency ultra-low frequency oscillation suppression mode, that is, it is necessary to determine whether each wind turbine generator participates in the system frequency ultra-low frequency oscillation suppression process. It should be noted that there are many types of oscillation of the power system containing wind power, and the ultra-low frequency oscillation is different from the ordinary low frequency oscillation. The ordinary low frequency oscillation is the relative oscillation between wind turbine generators, which belongs to the problem of power angle stability. While the ultra-low frequency oscillation is the coherent oscillation of all wind turbine generators, which belongs to the problem of frequency stability. Different oscillation types correspond to different processing modes. Therefore, according to the characteristics of the ultra-low frequency oscillation, it is determined whether each wind turbine generator enters the system frequency ultra-low frequency oscillation suppression mode, that is, whether each wind turbine generator participates in the ultra-low frequency oscillation suppression process to suppress the oscillation.

[0050] 103, if any of the wind turbine generators enters the system frequency ultra-low frequency oscillation suppression mode, then the active output reference power of the target wind turbine generator is corrected according to the oscillation frequency and amplitude, so as to realize the suppression of the system frequency ultra-low frequency oscillation, and the target wind turbine generator is any wind turbine generator entering the system frequency ultra-low frequency oscillation suppression mode.

[0051] Further, if any wind turbine enters the system frequency ultra-low frequency oscillation suppression mode, that is, any wind turbine participates in the system frequency ultra-low frequency oscillation suppression process, then the active output reference power of the target wind turbine can be corrected according to the oscillation frequency and amplitude, so as to realize the suppression of the system frequency ultra-low frequency oscillation by using the wind turbine. It should be noted that the target wind turbine is any wind turbine that enters the system frequency ultra-low frequency oscillation suppression mode. It should be noted that the typical method for suppressing the phenomenon of power system ultra-low frequency oscillation mainly includes optimizing the control parameters of the prime mover and adding an additional damping controller to improve the system damping. In this embodiment, considering that the wind turbine has small single-machine capacity but good dynamic characteristics and fast active adjustment speed, the wind power frequency regulation is an ideal scheme for improving the system frequency stability.

[0052] The present application provides a power system ultra-low frequency oscillation suppression method, which is applied to a wind farm main control system. The method comprises the following steps: acquiring frequency signal data of a power system and rotor speeds of each wind turbine collected by a synchronous phasor measurement device, wherein the frequency signal data at least includes an oscillation frequency and an amplitude of the power system; determining whether each wind turbine enters a system frequency ultra-low frequency oscillation suppression mode by using the oscillation frequency and the rotor speeds of each wind turbine; and correcting active output reference power of a target wind turbine according to the oscillation frequency and the amplitude to realize suppression of the system frequency ultra-low frequency oscillation if any wind turbine enters the system frequency ultra-low frequency oscillation suppression mode, wherein the target wind turbine is any wind turbine that enters the system frequency ultra-low frequency oscillation suppression mode. The present application fully considers the flexible control potential of wind power frequency, can realize active participation of wind power in system frequency ultra-low frequency oscillation suppression, improve system damping and reduce system ultra-low frequency oscillation risk, and has far-reaching significance for fully tapping the potential of wind power frequency stability control and improving system operation stability.

[0053] Please refer to Figure 2 , Figure 2 Another flowchart of the power system ultra-low frequency oscillation suppression method in the embodiment of the present application is shown in FIG. 2. As shown in FIG. 2, the method is applied to a wind farm main control system. The method comprises the following steps: Figure 2 Figure 2

[0054] 201. Acquire frequency signal data of a power system and rotor speeds of each wind turbine collected by a synchronous phasor measurement device, wherein the frequency signal data at least includes an oscillation frequency and an amplitude of the power system;

[0055] 202. Determine whether each wind turbine enters a system frequency ultra-low frequency oscillation suppression mode by using the oscillation frequency and the rotor speeds of each wind turbine;

[0056] It should be noted that the contents of steps 201-202 are the same as those of steps 101-102 shown in FIG. 1.​​Figure 1 The contents of steps 101-102 are similar, and to avoid repetition, the contents of steps 101-102 are not described here again.

[0057] In one possible implementation, step 202 can include steps A-C as follows:

[0058] A. Determine the oscillation type of the power system using the oscillation frequency and a preset frequency threshold, the oscillation type including at least ultra-low frequency oscillation;

[0059] In this embodiment, the oscillation type of the power system can be determined using the oscillation frequency of the power system and a preset frequency threshold. The oscillation type includes, but is not limited to, ultra-low frequency oscillation. Different preset frequency thresholds correspond to different oscillation types. For example, the ultra-low frequency oscillation corresponds to a preset frequency threshold of 0.1 Hz. Thus, if the oscillation frequency of the power system is lower than the preset frequency threshold of 0.1 Hz, it is determined that the oscillation type of the power system is ultra-low frequency oscillation. The above is only an example and is not limited in a specific manner.

[0060] B. When the oscillation type of the power system is ultra-low frequency oscillation, determine whether each wind turbine enters the system frequency ultra-low frequency oscillation suppression mode using the rotor speed of each wind turbine and the maximum power tracking mode lower limit speed;

[0061] C. When the rotor speed of any wind turbine is greater than the maximum power tracking mode lower limit speed, it is determined that the corresponding wind turbine enters the system frequency ultra-low frequency oscillation suppression mode.

[0062] Further, when the oscillation type of the power system is ultra-low frequency oscillation, the rotor speed of each wind turbine and the maximum power tracking mode lower limit speed can be used to determine whether each wind turbine enters the system frequency ultra-low frequency oscillation suppression mode. It should be noted that after determining that the oscillation type of the power system is ultra-low frequency oscillation, it is further necessary to determine whether the current wind turbine is running in the maximum power point tracking (MPPT) mode, i.e., the maximum power tracking mode. When the oscillation type of the power system is ultra-low frequency oscillation, and the rotor speed of the wind turbine is greater than the lower limit speed in the maximum power point tracking mode, it is determined that the corresponding wind turbine enters the ultra-low frequency oscillation suppression mode.

[0063] 203. If any wind turbine enters the system frequency ultra-low frequency oscillation suppression mode, the maximum releasable rotor kinetic energy of the target wind turbine is determined using the rotor speed of the target wind turbine and the maximum power tracking mode lower limit speed;

[0064] It can be understood that if any wind turbine enters the system frequency ultra-low frequency oscillation suppression mode, the ultra-low frequency oscillation suppression is performed by using the wind turbine. Among them, the target wind turbine is any wind turbine entering the system frequency ultra-low frequency oscillation suppression mode. Further, the maximum releasable rotor kinetic energy of the target wind turbine is determined by using the rotor speed of the target wind turbine and the maximum power tracking mode speed lower limit. It should be noted that the target wind turbine is the rotor speed greater than the maximum power tracking mode speed lower limit, so the target wind turbine has releasable rotor kinetic energy, and the maximum releasable rotor kinetic energy of the target wind turbine can be determined by using the rotor speed and the maximum power tracking mode speed lower limit.

[0065] In a feasible implementation mode, step 203: the maximum releasable rotor kinetic energy of the target wind turbine is determined by using the rotor speed of the target wind turbine and the maximum power tracking mode speed lower limit, which can be obtained by using the following formula:

[0066]

[0067] In the formula, ΔE WT is the maximum releasable rotor kinetic energy, H WT is the inherent inertia time constant of the wind turbine, ω1 is the current operating rotor speed of the wind turbine, and ω0 is the maximum power tracking mode speed lower limit.

[0068] 204, according to the rotor speed, operating wind speed and pitch angle of the target wind turbine, the current mechanical power and mechanical output power of the target wind turbine are determined;

[0069] It should be noted that the current mechanical power and mechanical output power of the target wind turbine can be determined by the rotor speed, operating wind speed and pitch angle of the target wind turbine. The current mechanical power and mechanical output power obtained are used to perform subsequent wind turbine active power correction and wind power participation in primary frequency modulation control strategy, including overspeed control and pitch angle control.

[0070] In a feasible implementation mode, step 204: according to the rotor speed, operating wind speed and pitch angle of the target wind turbine, the current mechanical power and mechanical output power of the target wind turbine are determined, including:

[0071]

[0072] In the formula, ρ is air density, C p is the wind energy capture efficiency coefficient; λ is the tip speed ratio, λ iis an intermediate variable, A is the wind energy capture area of the blade, ω is the rotor speed, v is the running wind speed, β is the pitch angle, R is the radius of the wind turbine, ω = ω1 is the current wind turbine mechanical power P1, and ω = ω1 and β = 0 is the mechanical power output P2.

[0073] 205. determining the mechanical power change value of the target wind turbine using the mechanical output power and the current mechanical power;

[0074] For example, the mechanical power change value ΔP of the target wind turbine in step 205 can be obtained by the following formula:

[0075] ΔP = P2 - P1

[0076] 206. determining the wind power suppression ultra-low frequency oscillation control parameter according to the maximum releasable rotor kinetic energy, the mechanical power change value, the oscillation frequency and the amplitude;

[0077] In one possible implementation, the wind power suppression ultra-low frequency oscillation control parameter is determined according to the obtained maximum releasable rotor kinetic energy, the mechanical power change value, the oscillation frequency and the amplitude. It should be noted that the oscillation frequency of the system is an equal-amplitude oscillation with an oscillation period T, so that the cumulative wind power response energy needs to reach at least half a period to reach the maximum value. Therefore, within half a period of the frequency change of the ultra-low frequency oscillation, the rotor kinetic energy contained in the target wind turbine is sufficient to continuously provide support for the active output reference power, and then step 206 determines the wind power suppression ultra-low frequency oscillation control parameter according to the maximum releasable rotor kinetic energy, the mechanical power change value, the oscillation frequency and the amplitude, including:

[0078]

[0079] In the formula, A0 is the amplitude of the system frequency oscillation, T is the oscillation period, K WT is the wind power suppression ultra-low frequency oscillation control parameter, ΔE WT is the maximum releasable rotor kinetic energy, and ΔP is the mechanical power change value

[0080] 207. correcting the active output reference power of the target wind turbine using the system frequency change, the wind power suppression ultra-low frequency oscillation control parameter and the reference power of the operating point of the target wind turbine before entering the system frequency ultra-low frequency oscillation suppression mode, to achieve suppression of the system frequency ultra-low frequency oscillation.

[0081] Furthermore, by utilizing the obtained system frequency changes, wind power suppression ultra-low frequency oscillation control parameters, and the reference power at the operating point of the target wind turbine before entering the system frequency ultra-low frequency oscillation suppression mode, the active power output reference power of the target wind turbine can be corrected, thereby achieving suppression of the system frequency ultra-low frequency oscillation. Specifically, correcting the active power output reference power of the target wind turbine refers to correcting the active power reference value of the wind turbine converter. For example, step 207 can correct the active power output reference power of the target wind turbine using the following formula:

[0082] P ref =P0+K WT Δf

[0083] In the formula, P ref P0 is the reference power for active power output, P0 is the reference power at the operating point of the target wind turbine before entering the ultra-low frequency oscillation suppression mode of the system, Δf is the system frequency change, and K is the reference power for active power output. WT These are control parameters for suppressing ultra-low frequency oscillations in wind power.

[0084] To clarify this embodiment, the following description uses the ultra-low frequency oscillation in the Yunnan asynchronous grid interconnection test as an example. The oscillation frequency in the Yunnan asynchronous grid interconnection test is approximately 0.05Hz, and the oscillation amplitude is approximately ±0.1Hz. For the wind turbine, the inherent inertial time constant is 5.04s, the wind speed for frequency regulation operation is 7m / s, the rated wind speed is 12m / s, the maximum rotor speed is 1.2pu, and the minimum rotor speed is 0.7pu. Currently, the wind speed is 8m / s, corresponding to a rotor speed of 0.8pu.

[0085] The wind farm's main control system determines the frequency of oscillation based on the system's frequency oscillation. When the frequency oscillation is below 0.1Hz, it is classified as ultra-low frequency oscillation. The system monitors the rotor speed of each wind turbine in the wind farm. When the rotor speed is higher than the lower limit of the maximum power point tracking mode, the corresponding wind turbine can participate in the system's ultra-low frequency oscillation suppression. The measured oscillation frequency is 0.05, which is less than the judgment threshold. When the wind turbine rotor speed is 0.8pu, which is higher than the judgment threshold (the lower limit of the maximum power point tracking mode), the wind turbine can participate in oscillation suppression.

[0086] According to the formula in step 203: ΔE was calculated WT =0.7560.

[0087] Furthermore, according to the formula in step 204:

[0088] Let ω = ω1 to obtain the current mechanical power P1 of the wind turbine, and let ω = ω1 and β = 0 to obtain the mechanical power output P2.

[0089] Further, the change ΔP of the mechanical power of the wind power during the oscillation suppression can be expressed as: ΔP=P2-P1

[0090] According to the formula of step 206: K is calculated as WT =31.3. According to K WT The active power reference of the wind turbine converter part is corrected according to the formula of step 207: P ref =P0+K WT Δf.

[0091] The application provides a power system ultra-low frequency oscillation suppression method, which is applied to a wind farm main control system, and comprises the following steps: acquiring frequency signal data of a power system and rotor speeds of wind turbines collected by a synchronous phasor measurement device; determining whether each wind turbine enters a system frequency ultra-low frequency oscillation suppression mode by using an oscillation frequency and the rotor speeds of the wind turbines; if any wind turbine enters the system frequency ultra-low frequency oscillation suppression mode, determining the maximum releasable rotor kinetic energy of a target wind turbine by using a rotor speed of the target wind turbine and a maximum power tracking mode rotor speed lower limit; determining current mechanical power and mechanical output power of the target wind turbine according to the rotor speed of the target wind turbine, an operating wind speed and a pitch angle; further determining a mechanical power change value of the target wind turbine and determining a wind power suppression ultra-low frequency oscillation control parameter; correcting active output reference power of the target wind turbine by using a system frequency change, the wind power suppression ultra-low frequency oscillation control parameter and reference power of an operating point of the target wind turbine before the target wind turbine enters the system frequency ultra-low frequency oscillation suppression mode, so as to realize suppression of the system frequency ultra-low frequency oscillation. The application fully considers the flexible control potential of wind power frequency, can realize active participation of wind power in system frequency ultra-low frequency oscillation suppression, improve system damping and reduce system ultra-low frequency oscillation risk, and has far-reaching significance for fully tapping the wind power frequency stability control potential and improving system operation stability.

[0092] Please refer to Figure 3 , Figure 3 The application provides a structure block diagram of a power system ultra-low frequency oscillation suppression device in an embodiment, as shown in the figure. Figure 3 The device is applied to a wind farm main control system, as shown in the figure. Figure 3 The device comprises the following components.

[0093] A data acquisition module 301 is configured to acquire frequency signal data of a power system and rotor speeds of wind turbines collected by a synchronous phasor measurement device, wherein the frequency signal data at least comprises an oscillation frequency and an amplitude of the power system.

[0094] The state determining module 302 is configured to determine whether each wind turbine enters the system frequency ultra-low frequency oscillation suppression mode by using the oscillation frequency and the rotor speed of each wind turbine.

[0095] The frequency suppression module 303 is configured to correct the active output reference power of the target wind turbine according to the oscillation frequency and the amplitude if any wind turbine enters the system frequency ultra-low frequency oscillation suppression mode, so as to suppress the system frequency ultra-low frequency oscillation, and the target wind turbine is any wind turbine entering the system frequency ultra-low frequency oscillation suppression mode.

[0096] It should be noted that the functions of each module in the device shown in Figure 3 are similar to the contents of each step in the method shown in Figure 1 , and to avoid repetition, details are not described here, and the contents of each step in the method shown in Figure 1 are referred to.

[0097] The present application provides a kind of power system ultra-low frequency oscillation suppression device, device is applied to wind farm main control system, device includes: data acquisition module: for obtaining the frequency signal data of power system and the rotor speed of each wind turbine collected by synchronous phasor measurement device, frequency signal data at least includes the oscillation frequency and amplitude of power system;State determining module: for using oscillation frequency and the rotor speed of each wind turbine, determine whether each wind turbine enters system frequency ultra-low frequency oscillation suppression mode;Frequency suppression module: for if any wind turbine enters system frequency ultra-low frequency oscillation suppression mode, then according to the oscillation frequency and the amplitude, the active output reference power of target wind turbine is corrected, realizes the suppression to system frequency ultra-low frequency oscillation, and target wind turbine is any wind turbine entering system frequency ultra-low frequency oscillation suppression mode.The present application fully considers the flexible control potential of wind power frequency, can realize that wind power actively participates in system frequency ultra-low frequency oscillation suppression, improves system damping and reduces system ultra-low frequency oscillation risk, and it has far-reaching significance to fully tap the potential of wind power frequency stability control and improve the stability of system operation.

[0098] Figure 4 The internal structure of the computer device in one embodiment is shown. The computer device can be a terminal or a server. As Figure 4 shown, the computer device includes a processor, a memory and a network interface connected by a system bus. The memory includes a non-volatile storage medium and an internal memory. The non-volatile storage medium of the computer device stores an operating system, and can also store a computer program, which, when executed by the processor, can enable the processor to implement the above method. The internal memory can also store a computer program, which, when executed by the processor, can enable the processor to execute the above method. Those skilled in the art can understand that Figure 4The structure shown is merely a block diagram of a portion of the structure related to the present application and does not constitute a limitation on the computer device to which the present application is applied. Specific computer devices may include more or fewer components than those shown in the figure, or combine certain components, or have different component arrangements.

[0099] In one embodiment, a computer device is provided, including a memory and a processor, the memory storing a computer program that, when executed by the processor, causes the processor to perform actions such as... Figure 1 or Figure 2 The steps of the method shown.

[0100] In one embodiment, a computer-readable storage medium is provided storing a computer program that, when executed by a processor, causes the processor to perform the following actions: Figure 1 or Figure 2 The steps of the method shown.

[0101] Those skilled in the art will understand that all or part of the processes in the above embodiments can be implemented by a computer program instructing related hardware. The program can be stored in a non-volatile computer-readable storage medium, and when executed, it can include the processes of the embodiments described above. Any references to memory, storage, databases, or other media used in the embodiments provided in this application can include non-volatile and / or volatile memory. Non-volatile memory can include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM), or flash memory. Volatile memory can include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM is available in various forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), dual data rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous link DRAM (SLDRAM), RAMbus direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and RAMbus dynamic RAM (RDRAM), etc.

[0102] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0103] The above-described embodiments are merely illustrative of several embodiments of the present application, which are described in more detail and in a specific manner, but should not be construed as limiting the scope of the patent of the present application. It should be noted that, for those of ordinary skill in the art, several modifications and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application should be subject to the appended claims.

Claims

1. A method for power system ultra-low frequency oscillation suppression, characterized in that, The method is applied to a wind farm master control system, and the method comprises: acquiring frequency signal data of a power system and rotor speeds of each wind turbine collected by a synchronous phasor measurement device, the frequency signal data at least comprising an oscillation frequency and an amplitude of the power system; determining whether each wind turbine enters a system frequency ultra-low frequency oscillation suppression mode by using the oscillation frequency and the rotor speeds of each wind turbine; if any wind turbine enters the system frequency ultra-low frequency oscillation suppression mode, correcting active output reference power of a target wind turbine according to the oscillation frequency and the amplitude to realize suppression of the system frequency ultra-low frequency oscillation, the target wind turbine being any wind turbine entering the system frequency ultra-low frequency oscillation suppression mode; wherein the correcting of the active output reference power of the target wind turbine according to the oscillation frequency and the amplitude to realize suppression of the system frequency ultra-low frequency oscillation comprises: determining maximum releasable rotor kinetic energy of the target wind turbine by using the rotor speed of the target wind turbine and a maximum power tracking mode rotor speed lower limit; determining current mechanical power and mechanical output power of the target wind turbine according to the rotor speed, an operating wind speed and a pitch angle of the target wind turbine; determining a mechanical power change value of the target wind turbine by using the mechanical output power and the current mechanical power; determining a wind power ultra-low frequency oscillation suppression control parameter according to the maximum releasable rotor kinetic energy, the mechanical power change value, the oscillation frequency and the amplitude; correcting the active output reference power of the target wind turbine by using a system frequency change, the wind power ultra-low frequency oscillation suppression control parameter and reference power of an operating point of the target wind turbine before the target wind turbine enters the system frequency ultra-low frequency oscillation suppression mode to realize suppression of the system frequency ultra-low frequency oscillation; wherein, within a half cycle of a frequency change of the ultra-low frequency oscillation, rotor kinetic energy contained in the target wind turbine is sufficient to continuously provide support for the active output reference power, and the determining of the wind power ultra-low frequency oscillation suppression control parameter according to the maximum releasable rotor kinetic energy, the mechanical power change value, the oscillation frequency and the amplitude comprises: In the formula, is the amplitude of the system frequency oscillation, T is the oscillation period, is the wind power suppression ultra-low frequency oscillation control parameter, is the maximum releasable rotor kinetic energy, is the mechanical power change value.

2. The method of claim 1, wherein, the determining of whether each wind turbine enters the system frequency ultra-low frequency oscillation suppression mode by using the oscillation frequency and the rotor speeds of each wind turbine comprises: determining an oscillation type of the power system by using the oscillation frequency and a preset frequency threshold, the oscillation type at least comprising an ultra-low frequency oscillation; when the oscillation type of the power system is the ultra-low frequency oscillation, determining whether each wind turbine enters the system frequency ultra-low frequency oscillation suppression mode by using the rotor speeds of each wind turbine and a maximum power tracking mode rotor speed lower limit; when the rotor speed of any wind turbine is greater than the maximum power tracking mode rotor speed lower limit, it is determined that the corresponding wind turbine enters the system frequency ultra-low frequency oscillation suppression mode.

3. The method of claim 1, wherein, the determining of the maximum releasable rotor kinetic energy of the target wind turbine by using the rotor speed of the target wind turbine and a maximum power tracking mode rotor speed lower limit comprises: wherein is the maximum releasable rotor kinetic energy, is the inherent inertia time constant of the wind turbine, is the current operating rotor speed of the wind turbine, is the maximum power tracking mode rotor speed lower limit.

4. The method of claim 1, wherein, The determining the current mechanical power and the mechanical output power of the target wind turbine according to the rotor speed, the operating wind speed and the pitch angle of the target wind turbine comprises: wherein: is the air density, is the wind energy capture efficiency coefficient; is the tip speed ratio, is an intermediate variable, is the blade wind energy capture area, is the rotor rotational speed, is the operating wind speed, is the pitch angle, R is the wind turbine rotor radius, let gives the current wind turbine mechanical power P1, let and = 0 gives the mechanical power output as P2.​​ 5. The method of claim 1, wherein, The correcting the active output reference power of the target wind turbine by using the system frequency variation, the wind power suppression ultra-low frequency oscillation control parameter and the reference power of the operating point of the target wind turbine before entering the system frequency ultra-low frequency oscillation suppression mode comprises: wherein P ref is the active output reference power, P ref,0 is the reference power for the target wind turbine to operate at before entering the frequency oscillation damping mode, is the system frequency variation, is the wind power damping ultra-low frequency oscillation control parameter.

6. A power system ultra-low frequency oscillation suppression device, characterized by, The device is applied to a wind farm main control system, and the device comprises: The data acquisition module is configured to acquire frequency signal data of a power system and rotor speeds of wind turbines collected by a synchronous phasor measurement device, wherein the frequency signal data at least comprises an oscillation frequency and an amplitude of the power system; The state determination module is configured to determine whether the wind turbines enter a system frequency ultra-low frequency oscillation suppression mode by using the oscillation frequency and the rotor speeds of the wind turbines; The frequency suppression module is configured to correct the active output reference power of a target wind turbine according to the oscillation frequency and the amplitude if any of the wind turbines enters the system frequency ultra-low frequency oscillation suppression mode, so as to suppress the system frequency ultra-low frequency oscillation, wherein the target wind turbine is any wind turbine entering the system frequency ultra-low frequency oscillation suppression mode; The frequency suppression module is configured to determine the maximum releasable rotor kinetic energy of the target wind turbine by using the rotor speed and the maximum power tracking mode lower limit speed of the target wind turbine, determine the current mechanical power and the mechanical output power of the target wind turbine according to the rotor speed, the operating wind speed and the pitch angle of the target wind turbine, determine the mechanical power variation value of the target wind turbine by using the mechanical output power and the current mechanical power, determine the wind power suppression ultra-low frequency oscillation control parameter according to the maximum releasable rotor kinetic energy, the mechanical power variation value, the oscillation frequency and the amplitude, correct the active output reference power of the target wind turbine by using the system frequency variation, the wind power suppression ultra-low frequency oscillation control parameter and the reference power of the operating point of the target wind turbine before entering the system frequency ultra-low frequency oscillation suppression mode, and suppress the system frequency ultra-low frequency oscillation. The determining the wind power suppression ultra-low frequency oscillation control parameter according to the maximum releasable rotor kinetic energy, the mechanical power variation value, the oscillation frequency and the amplitude comprises: In the formula, is the amplitude of the system frequency oscillation, T is the oscillation period, is the wind power suppression ultra-low frequency oscillation control parameter, is the maximum releasable rotor kinetic energy, is the mechanical power change value.

7. A computer readable storage medium storing a computer program, characterized in that, The computer program is executed by the processor to enable the processor to perform the steps of the method according to any one of claims 1 to 5. 8.A computer device, comprising a memory and a processor, and characterized in that, The memory stores the computer program, and the computer program is executed by the processor to enable the processor to perform the steps of the method according to any one of claims 1 to 5.

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