Leakage detection method and device for energy accumulator of wind generating set

Abstract

The invention provides a leakage detection method and device for an energy accumulator of a wind generating set. The leakage detection method comprises the steps that in the starting stage of the wind generating set, loop hydraulic parameters of an energy accumulator of the hydraulic variable-pitch system, environment temperature parameters of the energy accumulator and volume parameters of liquid discharged from starting of a hydraulic pump of the hydraulic variable-pitch system are obtained in real time; based on the loop hydraulic parameters, the environment temperature parameters and the liquid volume parameters which are obtained in real time, gas quality parameters of the energy accumulator are estimated; and under the condition that the gas quality parameter is lower than a first preset threshold value, it is determined that the energy accumulator leaks.

Description

Technical Field

[0001] The present disclosure generally relates to the field of wind power generation technology, and more specifically, to a leakage detection method and device for an accumulator of a wind power generator set. Background Art

[0002] Energy is the main material basis of social economy and human life, and is the driving force of social development. However, the reserves of non-renewable energy such as oil, coal, and natural gas, which are the main pillars of the world's energy, are decreasing day by day. Countries around the world are developing wind power generation. As a new energy source, wind power has formed a mature scale. Wind turbines (hereinafter referred to as wind turbines) are devices that convert wind energy into electrical energy. Hydraulic variable pitch systems are widely used in large wind turbines. The safety of their backup energy is crucial to the safety and power generation performance of the entire machine.

[0003] The detection device of a wind turbine is of great significance to the performance, reliability and economy of the unit. Existing detection devices cannot diagnose the leakage of the accumulator of the hydraulic pitch system with high accuracy, and if a device (e.g., a sensor) is added to directly detect the position of the accumulator piston, it will lead to increased costs and a higher possibility of gas leakage. Summary of the invention

[0004] An exemplary embodiment of the present disclosure provides a method and device for detecting leakage of an accumulator of a wind turbine generator set, which can achieve high-accuracy diagnosis of accumulator leakage without adding additional sensors.

[0005] According to a first aspect of an embodiment of the present disclosure, a method for detecting leakage of an accumulator of a wind turbine is provided, comprising: in a startup phase of the wind turbine, acquiring in real time loop hydraulic parameters of an accumulator of a hydraulic pitch system, ambient temperature parameters of the accumulator, and volume parameters of liquid discharged by a hydraulic pump of the hydraulic pitch system since startup; estimating a gas quality parameter of the accumulator based on the loop hydraulic parameters, ambient temperature parameters, and liquid volume parameters acquired in real time; and determining that the accumulator is leaking when the gas quality parameter is lower than a first preset threshold.

[0006] Optionally, the step of estimating the gas mass parameter of the accumulator based on the circuit hydraulic parameters, ambient temperature parameters and liquid volume parameters acquired in real time comprises: estimating the gas temperature parameter of the accumulator based on the ambient temperature parameter acquired in real time; estimating the gas volume parameter of the accumulator based on the liquid volume parameter acquired in real time; estimating the gas mass parameter of the accumulator based on the circuit hydraulic parameters, estimated gas temperature parameters and gas volume parameters acquired in real time.

[0007] Optionally, the step of estimating the gas quality parameters of the accumulator based on the circuit hydraulic parameters acquired in real time, the estimated gas temperature parameters and the gas volume parameters includes: estimating the gas quality parameters of the accumulator in real time through a Kalman filter based on the circuit hydraulic parameters acquired in real time, the estimated gas temperature parameters and the gas volume parameters.

[0008] Optionally, the Kalman filter is constructed based on the Benedict-Weider-Rubin equation regarding a circuit hydraulic parameter, a gas temperature parameter, and a gas volume parameter of the accumulator.

[0009] Optionally, the Kalman filter is an extended Kalman filter; wherein, the step of estimating the gas quality parameters of the accumulator in real time through the Kalman filter based on the real-time acquired circuit hydraulic parameters, the real-time estimated gas temperature parameters and the gas volume parameters includes: based on the gas quality parameters estimated by the extended Kalman filter last time, the currently acquired circuit hydraulic parameters, the currently estimated gas volume parameters and the gas temperature parameters, obtaining the estimated gas quality parameters this time through the extended Kalman filter.

[0010] Optionally, the step of estimating the gas temperature parameter of the accumulator based on the ambient temperature parameter acquired in real time includes: obtaining the estimated gas temperature parameter based on the volume and pre-charge pressure of the accumulator, the gas temperature parameter estimated last time, and the ambient temperature parameter currently acquired; and / or, the step of estimating the gas volume parameter of the accumulator based on the liquid volume parameter acquired in real time includes: obtaining the estimated gas volume parameter based on the volume of the accumulator and the liquid volume parameter currently acquired.

[0011] Optionally, the leakage detection method further includes: acquiring circuit hydraulic parameters of the accumulator in real time during the operation stage of the wind turbine generator set; and determining whether the accumulator is leaking based on amplitude-frequency characteristics of the circuit hydraulic parameters acquired in real time.

[0012] Optionally, the amplitude-frequency feature includes: the amplitude of a frequency band lower than a preset frequency threshold.

[0013] Optionally, the step of determining whether the accumulator is leaking based on the amplitude-frequency characteristics of the circuit hydraulic parameters acquired in real time includes: performing wavelet transform on the circuit hydraulic parameters acquired in real time to obtain an approximate coefficient corresponding to a detail coefficient lower than the preset frequency threshold; and determining that the accumulator is leaking when the approximate coefficient is higher than a second preset threshold.

[0014] Optionally, the hydraulic pitch system comprises: an oil tank, a hydraulic pump, a hydraulic cylinder, a hydraulic valve group and an accumulator; wherein the piston of the hydraulic cylinder is connected to the blade bearing of the wind turbine generator set.

[0015] Optionally, the step of real-time acquiring the circuit hydraulic parameters of the accumulator of the hydraulic pitch system, the ambient temperature parameters of the accumulator, and the volume parameters of the liquid discharged by the hydraulic pump of the hydraulic pitch system since startup includes: acquiring the circuit hydraulic parameters in real time through a pressure sensor installed on the accumulator circuit of the hydraulic pitch system; acquiring the ambient temperature parameters in real time through a temperature sensor installed in the wind turbine generator set; and acquiring the liquid volume parameters in real time based on the liquid flow delivered by the hydraulic pump.

[0016] According to a second aspect of an embodiment of the present disclosure, a leakage detection device for an accumulator of a wind turbine generator set is provided, comprising: a data acquisition unit, configured to acquire, in real time during the startup phase of the wind turbine generator set, circuit hydraulic parameters of the accumulator of a hydraulic pitch system, ambient temperature parameters of the accumulator, and volume parameters of liquid discharged by a hydraulic pump of the hydraulic pitch system since startup; a gas mass estimation unit, configured to estimate a gas mass parameter of the accumulator based on the circuit hydraulic parameters, ambient temperature parameters, and liquid volume parameters acquired in real time; and a leakage determination unit, configured to determine that the accumulator is leaking when the gas mass parameter is lower than a first preset threshold value.

[0017] Optionally, the gas mass estimation unit is configured to: estimate the gas temperature parameter of the accumulator based on the ambient temperature parameter acquired in real time; estimate the gas volume parameter of the accumulator based on the liquid volume parameter acquired in real time; estimate the gas mass parameter of the accumulator based on the circuit hydraulic parameter acquired in real time, the estimated gas temperature parameter and the gas volume parameter.

[0018] Optionally, the gas mass estimation unit is configured to estimate the gas mass parameter of the accumulator in real time through a Kalman filter based on the circuit hydraulic parameters acquired in real time, the gas temperature parameters and the gas volume parameters estimated in real time.

[0019] Optionally, the Kalman filter is constructed based on the Benedict-Weider-Rubin equation regarding a circuit hydraulic parameter, a gas temperature parameter, and a gas volume parameter of the accumulator.

[0020] Optionally, the Kalman filter is an extended Kalman filter; wherein the gas quality estimation unit is configured to obtain the estimated gas quality parameters this time through the extended Kalman filter based on the gas quality parameters estimated last time by the extended Kalman filter, the currently acquired circuit hydraulic parameters, the currently estimated gas volume parameters and the gas temperature parameters.

[0021] Optionally, the gas mass estimation unit is configured to obtain the estimated gas temperature parameter based on the volume and pre-charge pressure of the accumulator, the gas temperature parameter estimated last time, and the currently acquired ambient temperature parameter; and / or, the gas mass estimation unit is configured to obtain the estimated gas volume parameter based on the volume of the accumulator and the currently acquired liquid volume parameter.

[0022] Optionally, the data acquisition unit is further configured to: acquire the circuit hydraulic parameters of the accumulator in real time during the operation stage of the wind turbine generator set; the leakage determination unit is further configured to: determine whether the accumulator is leaking based on the amplitude-frequency characteristics of the circuit hydraulic parameters acquired in real time.

[0023] Optionally, the amplitude-frequency feature includes: the amplitude of a frequency band lower than a preset frequency threshold.

[0024] Optionally, the leakage determination unit is configured to: perform wavelet transform on the circuit hydraulic parameters acquired in real time to obtain an approximate coefficient corresponding to a detail coefficient lower than the preset frequency threshold; and determine that the accumulator is leaking when the approximate coefficient is higher than a second preset threshold.

[0025] Optionally, the hydraulic pitch system comprises: an oil tank, a hydraulic pump, a hydraulic cylinder, a hydraulic valve group and an accumulator; wherein the piston of the hydraulic cylinder is connected to the blade bearing of the wind turbine generator set.

[0026] Optionally, the data acquisition unit is configured to: acquire circuit hydraulic parameters in real time through a pressure sensor installed on the accumulator circuit of the hydraulic pitch system; acquire ambient temperature parameters in real time through a temperature sensor installed in the wind turbine generator set; and acquire liquid volume parameters in real time based on the liquid flow delivered by the hydraulic pump.

[0027] According to a third aspect of an embodiment of the present disclosure, there is provided a computer-readable storage medium storing instructions, which, when executed by a processor of an electronic device, enables the electronic device to perform the leakage detection method as described above.

[0028] According to a fourth aspect of an embodiment of the present disclosure, an electronic device is provided, comprising: a processor; and a memory storing computer executable instructions, wherein the computer executable instructions, when executed by the processor, prompt the processor to execute the leakage detection method as described above.

[0029] According to the exemplary embodiment of the present disclosure, the wind turbine generator accumulator leakage detection method and device can realize high-accuracy diagnosis of accumulator leakage without adding additional sensors. In addition, the hydraulic pitch system accumulator leakage detection can be realized in both the startup stage and the operation stage of the unit, that is, the accumulator leakage can be diagnosed with high accuracy under all working conditions.

[0030] In the following description, some aspects and / or advantages of the general inventive concept will be set forth, and some other aspects and / or advantages will be known through the following description or the implementation of the general inventive concept. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] These and / or other aspects and advantages of the present application will become clearer and easier to understand from the following detailed description of the embodiments of the present application in conjunction with the accompanying drawings, in which:

[0032] Figure 1 A flow chart showing a leakage detection method of an energy storage device of a wind turbine generator system according to an exemplary embodiment of the present disclosure;

[0033] Figure 2 A structural schematic diagram of a hydraulic pitch system according to an exemplary embodiment of the present disclosure is shown;

[0034] Figure 3 A flow chart showing a method of estimating a gas quality parameter of an accumulator according to an exemplary embodiment of the present disclosure;

[0035] Figure 4 A flow chart showing a method for detecting leakage of an accumulator during the operation phase of a wind turbine generator system according to an exemplary embodiment of the present disclosure;

[0036] Figure 5 and Figure 6 An amplitude-frequency characteristic curve of a transfer function under different accumulator pre-charge pressures according to an exemplary embodiment of the present disclosure is shown;

[0037] Figure 7 A schematic diagram of wavelet transformation according to an exemplary embodiment of the present disclosure is shown;

[0038] Figure 8 A structural block diagram of a leakage detection device for an energy storage device of a wind turbine generator system according to an exemplary embodiment of the present disclosure is shown. DETAILED DESCRIPTION

[0039] Reference will now be made in detail to the embodiments of the present disclosure, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to like parts throughout. The embodiments will be described below with reference to the drawings in order to explain the present disclosure.

[0040] It should be noted that the terms "first", "second", etc. in the specification and claims of the present disclosure and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present disclosure described herein can be implemented in an order other than those illustrated or described herein. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present disclosure. Instead, they are merely examples of devices and methods consistent with some aspects of the present disclosure as detailed in the appended claims.

[0041] It should be noted that the phrase "at least one of the items" in the present disclosure includes three types of parallel situations: "any one of the items", "a combination of any number of the items", and "all of the items". For example, "including at least one of A and B" includes the following three parallel situations: (1) including A; (2) including B; (3) including A and B. Another example is "executing at least one of step 1 and step 2" which means the following three parallel situations: (1) executing step 1; (2) executing step 2; (3) executing step 1 and step 2.

[0042] Figure 1 A flow chart showing a leakage detection method for an energy storage device of a wind turbine generator system according to an exemplary embodiment of the present disclosure.

[0043] As an example, the leakage detection method of the accumulator of a wind turbine generator set according to the exemplary embodiment of the present disclosure can be executed by an electronic device with data processing capabilities. For example, the electronic device can be a hydraulic pitch system controller, a wind turbine generator set controller, or a wind farm controller. The embodiment of the present disclosure is not limited to this.

[0044] The hydraulic pitch system is mainly composed of an oil tank, a hydraulic pump, a hydraulic cylinder, a hydraulic valve group and an accumulator. Figure 2 A structural schematic diagram of a hydraulic pitch control system according to an exemplary embodiment of the present disclosure is shown. For example, the piston of the hydraulic cylinder is connected to the blade bearing to convert the linear motion made by the piston of the hydraulic cylinder when it is extended and retracted into the rotational motion of the blade bearing, and the blades of the wind turbine generator set rotate under the drive of the blade bearing to achieve pitch control.

[0045] Reference Figure 1 In step S101, during the startup phase of the wind turbine generator set (i.e., the start-up phase), the circuit hydraulic parameter Ps of the accumulator of the hydraulic pitch system, the ambient temperature parameter Ta of the accumulator, and the volume parameter Vp of the liquid discharged by the hydraulic pump of the hydraulic pitch system from the start are obtained in real time.

[0046] As an example, you can Figure 2The pressure sensor PI in the accumulator is used to obtain the circuit hydraulic parameter Ps of the accumulator. In an exemplary embodiment of the present disclosure, the circuit hydraulic pressure of the accumulator is approximately regarded as the gas pressure of the accumulator (ie, the pressure of the gas in the accumulator) Pg, that is, Ps=Pg.

[0047] As an example, the ambient temperature parameter Ta of the accumulator may be obtained by a temperature sensor. For example, the temperature sensor may be disposed in the unit to detect the temperature in the unit.

[0048] As an example, during the startup phase of the unit, as the hydraulic pump is started, the hydraulic pump begins to discharge liquid (e.g., hydraulic oil) from the oil tank to the circuit of the accumulator, that is, the volume of liquid discharged by the hydraulic pump increases with time from 0, and the increase is proportional to the volume of the hydraulic pump. Figure 2 Liquid flow rate q p As an example, the liquid flow rate q p The volume of liquid discharged by the hydraulic pump is obtained by time integration.

[0049] In step S102 , the gas mass parameter mg of the accumulator is estimated based on the circuit hydraulic parameters, the ambient temperature parameters, and the liquid volume parameters acquired in real time.

[0050] Specifically, based on the circuit hydraulic parameters, ambient temperature parameters, and liquid volume parameters acquired in real time, the gas mass parameter of the accumulator (ie, the mass of the gas in the accumulator) is estimated in real time.

[0051] As an example, the unit of the gas mass parameter mg may be kg.

[0052] In step S103 , when the gas quality parameter is lower than a first preset threshold, it is determined that the accumulator is leaking.

[0053] As an example, the value of the first preset threshold may be set according to the gas mass of the accumulator when the accumulator actually leaks.

[0054] The present disclosure considers that the gas quality parameter mg will not change when the accumulator does not leak, but if the accumulator leaks, the gas quality parameter will decrease. Therefore, it is proposed to determine whether the accumulator leaks by estimating the gas quality of the accumulator during the startup phase of the wind turbine generator set. Thus, the accumulator can be leaked during the startup of the unit without the need for additional tools, tooling, and procedures for special detection.

[0055] Figure 3 A flow chart showing a method of estimating a gas quality parameter of an accumulator according to an exemplary embodiment of the present disclosure.

[0056] Reference Figure 3In step S201, the gas temperature parameter Tg of the accumulator is estimated based on the ambient temperature parameter acquired in real time.

[0057] Specifically, the gas temperature parameter of the accumulator (i.e., the temperature of the gas in the accumulator) can be estimated in real time based on the ambient temperature parameter acquired in real time. As an example, the estimated gas temperature parameter can be obtained based on the volume Va and pre-charge pressure Ppc of the accumulator, the gas temperature parameter estimated last time, and the ambient temperature parameter currently acquired.

[0058] As an example, the differential of the gas temperature parameter with respect to time can be estimated by equation (1):

[0059]

[0060] Among them, the time constant C v It represents the heat capacity parameter corresponding to the gas volume; h represents the thermal conductivity coefficient of the gas container, which is related to the outer wall material of the accumulator; A represents the outer wall area of ​​the gas container.

[0061] As an example, the time constant τ can be estimated based on the pre-charge pressure Ppc and the accumulator volume Va by equation (2):

[0062] τ≈0.3·10 -5 ·p pc V a 0.33 +86.2 V a 0.49 (2)

[0063] As an example, since the detection in the startup phase is mainly used for long-term detection, the change period of mg is generally in months, the change of relative temperature can be considered as a constant, and the partial derivative of ps with respect to Tg is almost 0. Therefore, when estimating the differential of the gas temperature parameter with respect to time through formula (1), When , we can mainly consider the part before the minus sign and ignore the part after the minus sign.

[0064] As an example, the gas temperature parameter Tg estimated last time can be k-1 And the calculated value obtained by formula (1) The result of time integration is the estimated gas temperature parameter Tg. k .

[0065] In step S202 , a gas volume parameter Vg of the accumulator is estimated based on the liquid volume parameter acquired in real time.

[0066] Specifically, the gas volume parameter of the accumulator (i.e., the volume of the gas in the accumulator, the volume of the gas chamber of the accumulator) can be estimated in real time based on the liquid volume parameter obtained in real time. As an example, the estimated gas volume parameter Vg can be obtained based on the volume Va of the accumulator and the currently obtained liquid volume parameter Vp.

[0067] Before the hydraulic pump is started, there is no hydraulic oil in the accumulator, and the initial value of the gas volume parameter Vg0 is equal to the accumulator volume Va. As the pump is started, the gas volume parameter starts to decrease from Va, and the amount of decrease is proportional to the delivered liquid flow rate q p Regarding, for example, Represents the differential of the gas volume parameter with respect to time. Accordingly, the difference between the accumulator volume and the currently acquired liquid volume parameter can be used as the gas volume parameter estimated this time, that is, Vg=Va-Vp.

[0068] In step S203 , the gas mass parameter of the accumulator is estimated based on the circuit hydraulic parameters acquired in real time, the estimated gas temperature parameters and the gas volume parameters.

[0069] Specifically, the gas mass parameter of the accumulator may be estimated in real time based on the circuit hydraulic parameters, estimated gas temperature parameters, and gas volume parameters acquired in real time.

[0070] As an example, the gas quality parameter of the accumulator can be estimated in real time through a Kalman filter (KF) based on the real-time acquired circuit hydraulic parameters, the real-time estimated gas temperature parameters and the gas volume parameters. For example, the Kalman filter used can be an extended Kalman filter (Extended Kalman Filter, EKF).

[0071] The Kalman filter is an efficient optimal estimator (a set of mathematical equations) that provides a recursive calculation method to obtain a gas quality parameter (i.e., a target variable) from a circuit hydraulic parameter with noise, a gas temperature parameter, and a gas volume parameter (i.e., an intermediate variable).

[0072] As an example, the Kalman filter can be constructed based on the Benedict-Webb-Rubine equation (BWRequation) about the circuit hydraulic parameters, gas temperature parameters and gas volume parameters of the accumulator. In other words, the Kalman filter obtains an estimated value of the gas quality parameter by filtering the BWR equation.

[0073] As an example, the Benedict-Wade-Rubin equation may be expressed as:

[0074]

[0075] Among them, A0, B0, C0, a, b, c, α, γ, and R represent characteristic constants of nitrogen, e represents the base of natural logarithm, Vg represents the gas volume parameter, mg represents the gas mass parameter, Tg represents the gas temperature parameter, and ps represents the circuit hydraulic parameter (that is, the gas pressure parameter).

[0076] As an example, step S203 may include: based on the gas quality parameter estimated by the extended Kalman filter last time, the currently acquired circuit hydraulic parameter, the currently estimated gas volume parameter and the gas temperature parameter, obtaining the estimated gas quality parameter this time through the extended Kalman filter.

[0077] As an example, the EKF equation of the extended Kalman filter may be shown as equation (4), and mg may be iterated through equation (4).

[0078] Initialization (k=0)

[0079]

[0080]

[0081] R=cov(V k )=(10 5 [Pa]) 2

[0082] P0=100·Q

[0083] predict

[0084]

[0085]

[0086] renew

[0087]

[0088]

[0089]

[0090] P k|k =(IK k C k ) k|k-1 (4)

[0091] As an example, represents the predicted state vector; Represents the difference between the observed value y and the predicted value; P represents the state covariance matrix; Q represents the process noise matrix; A represents the state transfer matrix; K represents the filter gain; R represents the measurement noise matrix; C represents the measurement matrix; I represents the unit matrix of the same dimension as the state vector; k represents the kth moment.

[0092] As an example, Vg0 represents the initial value of the gas volume parameter, which is generally the volume of the accumulator; Tg0 represents the initial value of the gas temperature parameter, which is generally the initial ambient temperature of the accumulator; and mg0 represents the initial value of the gas mass parameter.

[0093] As an example, the specific forms of function f and function g can be shown as formula (5):

[0094]

[0095]

[0096] x(0)=x0 (5)

[0097] As an example,

[0098] The above exemplary embodiments are mainly used for accumulator leakage detection in the startup phase. In addition, the present disclosure also provides accumulator leakage detection during unit operation. Figure 4 A flow chart showing a method for detecting leakage of an accumulator during the operation stage of a wind turbine generator system according to an exemplary embodiment of the present disclosure.

[0099] Reference Figure 4 In step S301, during the operation phase of the wind turbine generator set, the circuit hydraulic parameters of the accumulator are obtained in real time.

[0100] In step S302, it is determined whether the accumulator is leaking based on the amplitude-frequency characteristics of the circuit hydraulic parameters acquired in real time.

[0101] As an example, the amplitude-frequency feature may include but is not limited to: the amplitude of the frequency segment below the preset frequency threshold. For example, the preset frequency threshold may be 0.1 MHz. It should be understood that the value of the preset frequency threshold may be set according to actual conditions and specific requirements.

[0102] In fact, the present disclosure obtains the expressions of δps and δTg as shown in equations (6) and (7) by taking partial derivatives of equation (3).

[0103] Δp s =K pv ΔV g +K pt ΔT g (6)

[0104]

[0105] in,

[0106] Based on equations (6) and (7), the transfer function between the gas pressure parameter and the liquid flow rate is obtained as shown in equation (8).

[0107]

[0108] in,

[0109] Through analysis, it can be obtained that the amplitude-frequency characteristics of this transfer function are related to the pre-charge pressure Ppc. The lower the pre-charge pressure, the higher the amplitude-frequency gain of the transfer function. For example, Figure 5 The disclosure takes into account that the gas leakage of the accumulator is equivalent to the change of the pre-charge pressure. This feature is mainly reflected in the change of the amplitude-frequency gain before 0.1MHz, such as Figure 6 As shown, therefore, the present disclosure proposes to determine whether the accumulator is leaking based on the amplitude of the gas pressure signal (ie, the circuit hydraulic parameter signal acquired in real time) before 0.1 MHz.

[0110] As an example, in order to obtain the amplitude-frequency characteristics of the gas pressure signal, the gas pressure signal can be processed using wavelet transform, as shown in formula (9):

[0111]

[0112] Among them, ψ represents the scaling function, φ represents the mother wavelet, a l The approximate coefficient of the lth level represents the low-frequency characteristics, that is, the assignment characteristics, d j represents the j-th level detail coefficient, i.e., the frequency characteristic, a l and d j This can be obtained by applying high-pass and low-pass filters with different cut-off frequencies to the measured signal, such as Figure 7 shown.

[0113] As an example, step S302 may include: performing wavelet transform on the circuit hydraulic parameters acquired in real time to obtain an approximate coefficient corresponding to a detail coefficient lower than a preset frequency threshold; and determining that the accumulator is leaking when the approximate coefficient is higher than a second preset threshold.

[0114] Specifically, the real-time loop hydraulic parameters (i.e., gas pressure signals) are subjected to wavelet transformation to obtain detail coefficients and approximate coefficients at all levels. If the i-th level detail coefficient d i If the frequency is lower than the preset frequency threshold, the approximate coefficient corresponding to the detail coefficient lower than the preset frequency threshold is: the i-th level approximate coefficient a i , where i is an integer greater than 0.

[0115] The present disclosure proposes to use a d i The corresponding a i The change in the amplitude of the gas pressure signal is judged. If the value of ai increases significantly, it means that the pre-charge pressure becomes lower, that is, there is a gas leakage (either internal or external leakage), so that the accumulator leakage can be determined.

[0116] According to an exemplary embodiment of the present disclosure, accumulator leakage diagnosis is performed through existing hydraulic pitch sensors and operating information, so that high-accuracy diagnosis of accumulator leakage can be achieved without adding additional sensors, and leakage detection of the hydraulic pitch system accumulator can be achieved during the startup and operation stages of the unit.

[0117] According to the exemplary embodiments of the present disclosure, the following technical effects can be achieved: (1) the accumulator can be detected without changing the design of the hydraulic system; (2) the accumulator can be detected without adding additional actions to the variable pitch system; (3) external leakage and internal leakage can be detected simultaneously; (4) the probability of missed alarms and false alarms in the detection is greatly reduced compared with the original judgment based solely on pressure.

[0118] Figure 8 The structural block diagram of the leakage detection device of the accumulator of the wind turbine generator set according to the exemplary embodiment of the present disclosure is shown. As an example, the leakage detection device can be set in the hydraulic pitch system controller, the wind turbine generator set controller, and the wind farm controller, and the present disclosure does not limit this.

[0119] like Figure 8 As shown, the leakage detection device for an energy accumulator of a wind turbine generator set according to an exemplary embodiment of the present disclosure includes: a data acquisition unit 101 , a gas quality estimation unit 102 , and a leakage determination unit 103 .

[0120] Specifically, the data acquisition unit 101 is configured to acquire in real time during the startup phase of the wind turbine the circuit hydraulic parameters of the accumulator of the hydraulic pitch system, the ambient temperature parameters of the accumulator, and the volume parameters of the liquid discharged by the hydraulic pump of the hydraulic pitch system since startup.

[0121] The gas quality estimation unit 102 is configured to estimate the gas quality parameter of the accumulator based on the circuit hydraulic parameters, the ambient temperature parameters, and the liquid volume parameters acquired in real time.

[0122] The leakage determination unit 103 is configured to determine that the accumulator is leaking when the gas quality parameter is lower than a first preset threshold.

[0123] As an example, the gas quality estimation unit 102 may be configured to: estimate the gas temperature parameter of the accumulator based on the ambient temperature parameter acquired in real time; estimate the gas volume parameter of the accumulator based on the liquid volume parameter acquired in real time; estimate the gas quality parameter of the accumulator based on the circuit hydraulic parameter acquired in real time, the estimated gas temperature parameter and the gas volume parameter.

[0124] Optionally, the gas quality estimation unit 102 may be configured to estimate the gas quality parameter of the accumulator in real time through a Kalman filter based on the circuit hydraulic parameters acquired in real time, the gas temperature parameters estimated in real time and the gas volume parameters.

[0125] Optionally, the Kalman filter may be constructed based on the Benedict-Weider-Rubin equation regarding the circuit hydraulic parameter, the gas temperature parameter and the gas volume parameter of the accumulator.

[0126] Optionally, the Kalman filter is an extended Kalman filter; wherein the gas quality estimation unit 102 can be configured to: based on the gas quality parameters estimated last time by the extended Kalman filter, the currently acquired circuit hydraulic parameters, the currently estimated gas volume parameters and the gas temperature parameters, obtain the estimated gas quality parameters this time through the extended Kalman filter.

[0127] Optionally, the gas quality estimation unit 102 may be configured to obtain the estimated gas temperature parameter based on the volume and pre-charge pressure of the accumulator, the gas temperature parameter estimated last time, and the currently acquired ambient temperature parameter.

[0128] As an example, the gas mass estimation unit 102 may be configured to obtain the estimated gas volume parameter based on the volume of the accumulator and the currently acquired liquid volume parameter.

[0129] As an example, the data acquisition unit 101 can also be configured to: acquire the circuit hydraulic parameters of the accumulator in real time during the operation stage of the wind turbine generator set; the leakage determination unit 103 can also be configured to: determine whether the accumulator is leaking based on the amplitude-frequency characteristics of the circuit hydraulic parameters acquired in real time.

[0130] As an example, the amplitude-frequency feature may include: the amplitude of a frequency band lower than a preset frequency threshold.

[0131] As an example, the leakage determination unit 103 may be configured to: perform wavelet transform on the circuit hydraulic parameters acquired in real time to obtain an approximate coefficient corresponding to a detail coefficient lower than the preset frequency threshold; and determine that the accumulator is leaking when the approximate coefficient is higher than a second preset threshold.

[0132] As an example, the hydraulic pitch system may include, but is not limited to: an oil tank, a hydraulic pump, a hydraulic cylinder, a hydraulic valve group, and an accumulator; wherein the piston of the hydraulic cylinder is connected to the blade bearing of the wind turbine generator set.

[0133] As an example, the data acquisition unit 101 can be configured to: obtain circuit hydraulic parameters in real time through a pressure sensor installed on the accumulator circuit of the hydraulic pitch system; obtain ambient temperature parameters in real time through a temperature sensor installed in the wind turbine generator set; and obtain liquid volume parameters in real time based on the liquid flow delivered by the hydraulic pump.

[0134] It should be understood that the specific processing performed by the leakage detection device of the energy storage device of the wind turbine generator set according to the exemplary embodiment of the present disclosure has been referred to. Figures 1 to 7 The details have been described in detail and will not be repeated here.

[0135] It should be understood that the various units in the leakage detection device for the energy storage device of the wind turbine generator set according to the exemplary embodiment of the present disclosure can be implemented as hardware components and / or software components. Those skilled in the art can implement the various units, for example, using a field programmable gate array (FPGA) or an application specific integrated circuit (ASIC) according to the processing performed by the various defined units.

[0136] An exemplary embodiment of the present disclosure provides a computer-readable storage medium storing instructions, and when the instructions are executed by a processor of an electronic device, the electronic device is enabled to perform the leakage detection method of the energy storage device of the wind turbine generator set as described in the above exemplary embodiment. The computer-readable storage medium is any data storage device that can store data read by a computer system. Examples of computer-readable storage media include: read-only memory, random access memory, read-only optical disk, magnetic tape, floppy disk, optical data storage device, and carrier wave (such as data transmission through the Internet via a wired or wireless transmission path).

[0137] The electronic device according to the exemplary embodiment of the present disclosure includes: at least one processor; at least one memory storing computer executable instructions, wherein the computer executable instructions, when executed by the at least one processor, prompt the at least one processor to execute the leakage detection method of the accumulator of the wind turbine generator set as described in the above exemplary embodiment. As an example, the electronic device can be a hydraulic pitch system controller, a wind turbine generator set controller, or a wind farm controller, which is not limited by the embodiment of the present disclosure.

[0138] Although some exemplary embodiments of the present disclosure have been shown and described, it will be appreciated by those skilled in the art that modifications may be made to these embodiments without departing from the scope and spirit of the present disclosure as defined by the claims and their equivalents.

Claims

1. A method for detecting leakage of an accumulator of a wind turbine generator set, characterized in that: include: During the start-up phase of the wind turbine generator set, the circuit hydraulic parameters of the accumulator of the hydraulic pitch system, the ambient temperature parameters of the accumulator, and the volume parameters of the liquid discharged by the hydraulic pump of the hydraulic pitch system from the start-up are obtained in real time; estimating a gas mass parameter of the accumulator based on the circuit hydraulic parameters, ambient temperature parameters, and liquid volume parameters acquired in real time; When the gas quality parameter is lower than a first preset threshold, it is determined that the accumulator is leaking.

2. The leakage detection method according to claim 1, characterized in that: The step of estimating the gas mass parameter of the accumulator based on the circuit hydraulic parameters, ambient temperature parameters, and liquid volume parameters acquired in real time comprises: estimating a gas temperature parameter of the accumulator based on the ambient temperature parameter acquired in real time; estimating a gas volume parameter of the accumulator based on the liquid volume parameter acquired in real time; A gas quality parameter of the accumulator is estimated based on the circuit hydraulic parameters, the estimated gas temperature parameters and the gas volume parameters acquired in real time.

3. The leakage detection method according to claim 2, characterized in that: The step of estimating the gas quality parameter of the accumulator based on the circuit hydraulic parameters, estimated gas temperature parameters and gas volume parameters acquired in real time comprises: Based on the circuit hydraulic parameters acquired in real time, the gas temperature parameters and the gas volume parameters estimated in real time, the gas mass parameters of the accumulator are estimated in real time through a Kalman filter.

4. The leakage detection method according to claim 3, characterized in that: The Kalman filter is constructed based on the Benedict-Weider-Rubin equation regarding a circuit hydraulic parameter, a gas temperature parameter, and a gas volume parameter of the accumulator.

5. The leakage detection method according to claim 3 or 4, characterized in that: The Kalman filter is an extended Kalman filter; The step of estimating the gas quality parameter of the accumulator in real time by using a Kalman filter based on the loop hydraulic parameters acquired in real time, the gas temperature parameters estimated in real time and the gas volume parameters comprises: Based on the gas quality parameter estimated by the extended Kalman filter last time, the currently acquired circuit hydraulic parameter, the currently estimated gas volume parameter and the gas temperature parameter, the estimated gas quality parameter this time is obtained by the extended Kalman filter.

6. The leakage detection method according to claim 2, characterized in that: The step of estimating the gas temperature parameter of the accumulator based on the ambient temperature parameter acquired in real time comprises: obtaining the estimated gas temperature parameter based on the volume and pre-charge pressure of the accumulator, the gas temperature parameter estimated last time, and the ambient temperature parameter currently acquired; And / or, the step of estimating the gas volume parameter of the accumulator based on the liquid volume parameter acquired in real time includes: obtaining the estimated gas volume parameter based on the volume of the accumulator and the liquid volume parameter currently acquired.

7. The leakage detection method according to claim 1, characterized in that: The leakage detection method further comprises: During the operation phase of the wind turbine generator set, the circuit hydraulic parameters of the accumulator are obtained in real time; Based on the amplitude-frequency characteristics of the circuit hydraulic parameters acquired in real time, it is determined whether the accumulator is leaking.

8. The leakage detection method according to claim 7, characterized in that: The amplitude-frequency feature includes: the amplitude of the frequency segment below a preset frequency threshold.

9. The leakage detection method according to claim 8, characterized in that: The step of determining whether the accumulator is leaking based on the amplitude-frequency characteristics of the circuit hydraulic parameters acquired in real time comprises: Performing wavelet transformation on the circuit hydraulic parameters acquired in real time to obtain approximate coefficients corresponding to detail coefficients below the preset frequency threshold; In the case where the approximation coefficient is higher than a second preset threshold value, it is determined that the accumulator is leaking.

10. The leakage detection method according to claim 1, characterized in that: The hydraulic pitch system comprises: an oil tank, a hydraulic pump, a hydraulic cylinder, a hydraulic valve group and an accumulator; Wherein, the piston of the hydraulic cylinder is connected to the blade bearing of the wind turbine generator set.

11. The leakage detection method according to claim 1 or 10, characterized in that: The step of obtaining in real time the circuit hydraulic parameters of the accumulator of the hydraulic pitch system, the ambient temperature parameters of the accumulator, and the volume parameters of the liquid discharged by the hydraulic pump of the hydraulic pitch system since startup comprises: The circuit hydraulic parameters are obtained in real time by means of a pressure sensor installed on the accumulator circuit of the hydraulic pitch system; Acquiring ambient temperature parameters in real time through a temperature sensor installed in the wind turbine generator set; The liquid volume parameter is acquired in real time based on the liquid flow delivered by the hydraulic pump.

12. A leakage detection device for an accumulator of a wind turbine generator set, characterized in that: include: A data acquisition unit is configured to acquire, in real time during the startup phase of the wind turbine generator set, a circuit hydraulic parameter of an accumulator of a hydraulic pitch system, an ambient temperature parameter of the accumulator, and a volume parameter of liquid discharged by a hydraulic pump of the hydraulic pitch system since startup; a gas quality estimation unit configured to estimate a gas quality parameter of the accumulator based on a circuit hydraulic parameter, an ambient temperature parameter, and a liquid volume parameter acquired in real time; The leakage determination unit is configured to determine that the accumulator is leaking when the gas quality parameter is lower than a first preset threshold.

13. A computer-readable storage medium storing instructions, characterized in that: When the instructions are executed by a processor of an electronic device, the electronic device is enabled to execute the leakage detection method according to any one of claims 1 to 11.

14. An electronic device, characterized in that: The electronic device comprises: processor; a memory storing computer executable instructions, Wherein, when the computer executable instructions are executed by the processor, the processor is prompted to perform the leakage detection method according to any one of claims 1 to 11.

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