Vibration isolation performance monitoring method and device for elastic support of wind turbine generator

Abstract

The invention discloses a vibration isolation performance monitoring method and device for an elastic support of a wind turbine generator. The method comprises the following steps: acquiring a vibration acceleration signal of the elastic support to be measured and a rotating speed signal of a generator; acquiring vibration order ratio signals corresponding to the specific order of the rotating speed signal in the active and passive end vibration acceleration signals as target vibration excitation and target vibration response by using a self-adaptive tracking filtering algorithm; calculating a current frequency response function between the target vibration excitation and the target vibration response; calculating a distortion degree characteristic index and a deviation direction characteristic index between the current frequency response function and the initial frequency response function; fitting the distortion degree characteristic indexes to obtain a distortion degree time trend curve; the second-order difference of the distortion degree time trend curve is calculated; and judging the vibration isolation performance according to the distortion degree characteristic index, a preset distortion degree characteristic index threshold, the deviation direction characteristic index and the second-order difference. According to the invention, the vibration isolation performance of the elastic support is accurately monitored in real time.

Description

Technical Field

[0001] The present invention relates to the technical field of wind turbine generator systems, and in particular to a method and device for monitoring vibration isolation performance of elastic supports of wind turbine generator systems. Background Art

[0002] Elastic supports are important vibration isolation components in the transmission chain of wind turbines. In doubly fed units, they are divided into gearbox elastic supports and generator elastic supports. They buffer and absorb the vibration and impact energy of the gearbox and generator, thereby increasing the service life of mechanical components and the operational stability of the unit.

[0003] During operation, the elastic support of a wind turbine is subjected to steady-state and transient excitations transmitted by rotating components. The alternating loads generated by steady-state excitations cause the elastic support to heat up, age, and slowly fatigue. The impact generated by transient excitations may cause the elastic support to be instantaneously overloaded, thereby causing the rubber material to collapse or extrude. The long-term accumulation of these two types of damage will cause the elastic support's stiffness, damping and other characteristic parameters to change, resulting in a decrease in vibration isolation performance, and an increase in the vibration and impact intensity of mechanical components such as the frame, gearbox, and generator, making it prone to failures such as damage to gear tooth surfaces, generator rotors, and bearings.

[0004] When the vibration isolation performance of the elastic support of a wind turbine is degraded, it needs to be replaced in a timely manner to avoid greater economic losses such as damage to the gearbox and generator and to ensure the smooth operation of the unit. However, the degradation of the vibration isolation performance of the elastic support caused by heat, ozone and fatigue aging is manifested in the dynamic vibration characteristics, which is difficult to detect through operation and maintenance methods such as human observation or mechanical dimension measurement. Secondly, when the crushing and extrusion of the rubber material is discovered, the unit has often been operating in a high-risk state for a long time. Therefore, it is necessary to monitor the vibration isolation performance of the elastic support in real time to achieve predictive maintenance and reduce the number and cost of maintenance.

[0005] Currently, there are two main monitoring methods for wind turbine elastic supports: 1) stiffness detection under resonance; 2) displacement offset measurement. However, during the implementation of the invention, the inventors discovered that the existing wind turbine elastic support monitoring methods have the following deficiencies: 1) Stiffness detection under resonance only measures the vibration acceleration response at the generator end to determine the resonance state and system stiffness changes, and cannot independently monitor each elastic support. In addition, the original acceleration signal at the generator end contains mixed vibration components such as the high-speed shaft, coupling, gearbox, and generator base. Therefore, the resonance does not come only from the elastic support, but is also affected by the critical speed of the rotor and the resonance of the generator structure. Furthermore, only monitoring stiffness will ignore the impact of the damping characteristics on the elastic support, resulting in large monitoring errors and poor operability and comprehensiveness. 2) Displacement offset measurement can only monitor material yielding after a serious accident in the elastic support, and cannot monitor slight changes in vibration isolation performance caused by aging of the elastic support due to factors such as fatigue, heat, and ozone, resulting in low predictability and sensitivity. Summary of the Invention

[0006] The purpose of the present invention is to overcome the shortcomings of the prior art in which vibration isolation performance monitoring of elastic supports of wind turbines is not comprehensive, has large errors, and is not operable, and to provide a method and device for monitoring vibration isolation performance of elastic supports of wind turbines.

[0007] The technical solution of the present invention provides a method for monitoring the vibration isolation performance of elastic supports of a wind turbine generator set, comprising:

[0008] Acquire a vibration acceleration signal of the elastic support to be tested and a speed signal of the generator, wherein the vibration acceleration signal includes a vibration acceleration signal of an active end and a vibration acceleration signal of a passive end of the elastic support to be tested;

[0009] Using an adaptive tracking filtering algorithm, obtaining a vibration order ratio signal corresponding to a specific order of the rotational speed signal in the active-end vibration acceleration signal as a target vibration excitation of the elastic support to be tested, and obtaining a vibration order ratio signal corresponding to the specific order of the rotational speed signal in the passive-end vibration acceleration signal as a target vibration response of the elastic support to be tested;

[0010] calculating a current frequency response function between the target vibration excitation and the target vibration response;

[0011] Calculating a distortion characteristic index and a deviation direction characteristic index between the current frequency response function and the initial frequency response function;

[0012] Fitting the distortion characteristic index to obtain a distortion time trend curve;

[0013] Calculating the second-order difference of the distortion time trend curve;

[0014] The vibration isolation performance of the elastic support to be tested is determined according to the distortion characteristic index, the preset distortion characteristic index threshold, the deviation direction characteristic index and the second-order difference.

[0015] In one of the optional technical solutions, obtaining the vibration acceleration signal of the elastic support to be tested and the speed signal of the generator includes:

[0016] The vibration acceleration signal and the rotation speed signal are acquired according to a preset sampling length, sampling frequency and sampling interval.

[0017] In one of the optional technical solutions, the method of using an adaptive tracking filtering algorithm to obtain a vibration order ratio signal corresponding to a specific order of the rotational speed signal in the active end vibration acceleration signal as a target vibration excitation of the elastic support to be tested, and obtaining a vibration order ratio signal corresponding to the specific order of the rotational speed signal in the passive end vibration acceleration signal as a target vibration response of the elastic support to be tested, includes:

[0018] The target vibration excitation and the target vibration response are obtained by using a Kalman tracking filter algorithm and taking the input shaft of the generator as a reference axis.

[0019] In one of the optional technical solutions, the use of a Kalman tracking filter algorithm with the input shaft of the generator as a reference axis to obtain the target vibration excitation and the target vibration response includes:

[0020] Establish the observation equation:

[0021] y(n)=x(n)Θ(n)+ξ(n)

[0022]

[0023] Where n = 1, 2, 3, ..., N, Θ(n) is the modulation envelope of the vibration order ratio signal x(n), ω(m) is the speed signal, f s is a function of the sampling frequency, ξ(n) is the non-order-ratio component and noise in the original acceleration signal y(n);

[0024] The weighting factor is calculated using the following formula:

[0025]

[0026] Among them, r is the weighting factor, f H is the low-pass analysis bandwidth;

[0027] The minimum value of the sum of squares of the non-order ratio component, noise, and non-consistent term is calculated according to the weighting factor to obtain the target vibration excitation and the target vibration response.

[0028] In one of the optional technical solutions, calculating the current frequency response function between the target vibration excitation and the target vibration response includes:

[0029] The current frequency response function is calculated using the following formula:

[0030]

[0031]

[0032] Where: H0(n) is the initial frequency response function; H j (n) is the current frequency response function; X 01 (n), X 02 (n), X j1 (n), X j2 (n) are x 01 (n), x 02(n), x j1 (n), x j2 (n) is the Fourier transform amplitude spectrum.

[0033] In one of the optional technical solutions, calculating the distortion characteristic index and the deviation direction characteristic index between the current frequency response function and the initial frequency response function includes:

[0034] The distortion characteristic index and the deviation direction characteristic index are calculated using the following formula:

[0035]

[0036] Where ΔH j is the characteristic index of the distortion degree, ΔM j is the deviation direction characteristic indicator.

[0037] In one of the optional technical solutions, calculating the second-order difference of the distortion time trend curve includes:

[0038] The second-order difference is calculated using the following formula:

[0039] D j =ΔH j+1 -2ΔH j +ΔH j-1

[0040] Among them, D j is the second-order difference; ΔH j+1 is the distortion characteristic index at the next moment; ΔH j-1 is the distortion characteristic index of the previous moment.

[0041] In one of the optional technical solutions, judging the vibration isolation performance of the elastic support to be tested based on the distortion characteristic index, the preset distortion characteristic index threshold, the deviation direction characteristic index, and the second-order difference includes:

[0042] If the distortion characteristic index exceeds the distortion characteristic index threshold, the deviation direction characteristic index is positive, and the second-order difference is positive, it is determined that the vibration isolation performance of the elastic support to be tested has deteriorated, and the degree of degradation of the elastic support to be tested is high and rapidly progressing;

[0043] If the distortion characteristic index exceeds the distortion characteristic index threshold, the deviation direction characteristic index is a negative value, and the second-order difference is a positive value, it is determined that the vibration isolation performance of the elastic support to be tested is normal, and the degree of degradation of the elastic support to be tested is high and the degree of degradation is rapidly developing;

[0044] If the distortion characteristic index exceeds the distortion characteristic index threshold, the deviation direction characteristic index is a positive value, and the second-order difference is a negative value, it is determined that the vibration isolation performance of the elastic support to be tested has deteriorated, and the degradation degree of the elastic support to be tested is high and the degradation trend is stable;

[0045] If the distortion characteristic index exceeds the distortion characteristic index threshold, the deviation direction characteristic index is a negative value, and the second-order difference is a negative value, it is determined that the vibration isolation performance of the elastic support to be tested is normal, the degradation degree of the elastic support to be tested is high, and the degradation trend is stable;

[0046] If the distortion characteristic index does not exceed the distortion characteristic index threshold, the deviation direction characteristic index is positive, and the second-order difference is positive, it is determined that the vibration isolation performance of the elastic support to be tested has deteriorated, and the degree of degradation of the elastic support to be tested is low and the degree of degradation is rapidly developing;

[0047] If the distortion characteristic index does not exceed the distortion characteristic index threshold, the deviation direction characteristic index is a negative value, and the second-order difference is a positive value, it is determined that the vibration isolation performance of the elastic support to be tested is normal, and the degradation degree of the elastic support to be tested is low and the degradation degree is rapidly developing;

[0048] If the distortion characteristic index does not exceed the distortion characteristic index threshold, the deviation direction characteristic index is a positive value, and the second-order difference is a negative value, it is determined that the vibration isolation performance of the elastic support to be tested has deteriorated, and the degradation degree of the elastic support to be tested is low and the degradation trend is stable;

[0049] If the distortion characteristic index does not exceed the distortion characteristic index threshold, the deviation direction characteristic index is a negative value, and the second-order difference is a negative value, it is judged that the vibration isolation performance of the elastic support to be tested is normal, the degradation degree of the elastic support to be tested is low, and the degradation trend is stable.

[0050] In one of the optional technical solutions, the vibration isolation performance of the elastic support to be tested is judged according to the distortion characteristic index, the preset distortion characteristic index threshold, the deviation direction characteristic index and the second-order difference, and then further includes:

[0051] If it is determined that the vibration isolation performance of the elastic support to be tested has deteriorated, the degree of degradation of the elastic support to be tested is high and the degradation degree is rapidly developing, prompting to immediately replace the elastic support to be tested;

[0052] If it is determined that the vibration isolation performance of the elastic support to be tested is normal, and the deterioration degree of the elastic support to be tested is high and the deterioration degree is rapidly developing, a prompt is given to check the body and installation status of the elastic support to be tested;

[0053] If it is determined that the vibration isolation performance of the elastic support to be tested has deteriorated, the degree of degradation of the elastic support to be tested is high and the degradation trend is stable, a prompt is given to check the body, installation status and transmission chain vibration of the elastic support to be tested;

[0054] If it is determined that the vibration isolation performance of the elastic support to be tested is normal, and the degradation degree of the elastic support to be tested is high and the degradation trend is stable, it is suggested to check whether the body of the elastic support to be tested is contaminated and / or cracked;

[0055] If it is determined that the vibration isolation performance of the elastic support to be tested has deteriorated, and the degree of degradation of the elastic support to be tested is low and rapidly progressing, it is suggested to continuously monitor the characteristic indicators of the elastic support to be tested and to check the vibration of the transmission chain;

[0056] If it is determined that the vibration isolation performance of the elastic support to be tested is normal, and the degradation degree of the elastic support to be tested is low and the degradation degree is rapidly developing, it is prompted to continuously monitor the characteristic indicators of the elastic support to be tested;

[0057] If it is determined that the vibration isolation performance of the elastic support to be tested has deteriorated, the degree of degradation of the elastic support to be tested is low and the degradation trend is stable, it is suggested to check the vibration of the transmission chain;

[0058] If it is determined that the vibration isolation performance of the elastic support to be tested is normal, the degradation degree of the elastic support to be tested is low and the degradation trend is stable, it is suggested that no intervention measures are required.

[0059] The technical solution of the present invention further provides a vibration isolation performance monitoring device for elastic supports of a wind turbine generator set, comprising:

[0060] a first acquiring unit, configured to acquire a vibration acceleration signal of the elastic support to be tested and a rotational speed signal of the generator, wherein the vibration acceleration signal includes a vibration acceleration signal of an active end and a vibration acceleration signal of a passive end of the elastic support to be tested;

[0061] a second acquiring unit, configured to acquire, by using an adaptive tracking filtering algorithm, a vibration order ratio signal corresponding to a specific order of the rotational speed signal in the active-end vibration acceleration signal as a target vibration excitation of the elastic support to be tested, and to acquire a vibration order ratio signal corresponding to the specific order of the rotational speed signal in the passive-end vibration acceleration signal as a target vibration response of the elastic support to be tested;

[0062] a response function calculation unit, configured to calculate a current frequency response function between the target vibration excitation and the target vibration response;

[0063] a characteristic index calculation unit, configured to calculate a distortion characteristic index and a deviation direction characteristic index between the current frequency response function and the initial frequency response function;

[0064] A curve generating unit, configured to fit the distortion characteristic index to obtain a distortion time trend curve;

[0065] A difference calculation unit, used to calculate the second-order difference of the distortion time trend curve;

[0066] A judging unit is configured to judge the vibration isolation performance of the elastic support to be tested based on the distortion characteristic index, a preset distortion characteristic index threshold, the deviation direction characteristic index, and the second-order difference.

[0067] The above technical solution has the following beneficial effects: according to the changes in the frequency response functions of the active and passive ends of the elastic support to be tested, the distortion characteristic index and the deviation direction characteristic index of the elastic support to be tested are calculated, and the distortion characteristic index is fitted to obtain a distortion time trend curve, and the second-order difference of the distortion time trend curve is calculated. According to the distortion characteristic index, the preset distortion characteristic index threshold, the deviation direction characteristic index and the second-order difference, the vibration isolation performance of the elastic support to be tested is judged, and the vibration isolation performance of the elastic support to be tested is monitored in real time and accurately; and no additional complex sensing equipment is required except for the vibration sensor. The speed signal of the generator comes from the unit, and the system composition is simple and the cost is low. At the same time, by calculating the changes in the frequency response functions of the active and passive ends of the elastic support to be tested, the vibration transfer characteristic level of the elastic support body is monitored, which is not affected by the operating conditions of the unit and the external vibration interference of the elastic support, reduces errors, and has strong real-time performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0068] The disclosure of the present invention will become more easily understood with reference to the accompanying drawings. It should be understood that these drawings are for illustrative purposes only and are not intended to limit the scope of protection of the present invention. In the drawings:

[0069] Figure 1 A flowchart of a method for monitoring vibration isolation performance of elastic supports of a wind turbine generator system according to an embodiment of the present invention;

[0070] Figure 2 This is a schematic structural diagram of the elastic support of a wind turbine generator system according to the present invention;

[0071] Figure 3 It is a structural diagram of the relationship between the deviation characteristic index and the second-order difference;

[0072] Figure 4 This is a schematic diagram of the relationship between the time trend, threshold and second-order difference of the distortion characteristic indicator;

[0073] Figure 5 A flowchart of a method for monitoring vibration isolation performance of elastic supports of a wind turbine generator system according to another embodiment of the present invention;

[0074] Figure 6 A schematic structural diagram of a vibration isolation performance monitoring device for elastic supports of a wind turbine generator set provided by one embodiment of the present invention. DETAILED DESCRIPTION

[0075] The specific embodiments of the present invention will be further described below with reference to the accompanying drawings.

[0076] It is easy to understand that according to the technical solution of the present invention, a variety of structural modes and implementation modes can be replaced with each other by those skilled in the art without changing the essential spirit of the present invention. Therefore, the following specific embodiments and drawings are only exemplary descriptions of the technical solution of the present invention and should not be regarded as the entire invention or as a limitation or restriction of the technical solution of the invention.

[0077] The directional terms such as up, down, left, right, front, back, front, back, top, and bottom mentioned or possibly mentioned in this specification are defined relative to the structure shown in the drawings. They are relative concepts and may vary depending on the location and usage of the device. Therefore, these or other directional terms should not be interpreted as restrictive.

[0078] like Figure 1 As shown, an embodiment of the present invention provides a method for monitoring the vibration isolation performance of an elastic support of a wind turbine generator set, comprising:

[0079] Step S101: obtaining a vibration acceleration signal of the elastic support to be tested and a rotational speed signal of the generator, wherein the vibration acceleration signal includes a vibration acceleration signal of an active end and a vibration acceleration signal of a passive end of the elastic support to be tested;

[0080] Step S102: using an adaptive tracking filtering algorithm, obtaining a vibration order ratio signal corresponding to a specific order of the rotational speed signal in the active end vibration acceleration signal as a target vibration excitation of the elastic support to be tested, and obtaining a vibration order ratio signal corresponding to the specific order of the rotational speed signal in the passive end vibration acceleration signal as a target vibration response of the elastic support to be tested;

[0081] Step S103: Calculating a current frequency response function between the target vibration excitation and the target vibration response;

[0082] Step S104: calculating a distortion characteristic index and a deviation direction characteristic index between the current frequency response function and the initial frequency response function;

[0083] Step S105: fitting the distortion characteristic index to obtain a distortion time trend curve;

[0084] Step S106: Calculating the second-order difference of the distortion time trend curve;

[0085] Step S107: judging the vibration isolation performance of the elastic support to be tested according to the distortion characteristic index, the preset distortion characteristic index threshold, the deviation direction characteristic index and the second-order difference.

[0086] Specifically, in step S101, the controller obtains the vibration acceleration signal of the elastic support to be tested and the speed signal of the generator. The vibration acceleration signal is detected by a vibration acceleration sensor. The vibration acceleration sensor can be installed at the active end and passive end (hereinafter referred to as the active and passive ends) of the elastic support to be tested of the gear box and the generator respectively using a magnetic base. Figure 2 As shown, there are two gearbox elastic supports, located at the ends of the left and right torque arms of the gearbox. The active end measuring points are located in the z-direction of the torque arms, namely measuring points 1 and 2. The corresponding passive end measuring points are located in the z-direction of the gearbox elastic support frame, namely measuring points 3 and 4. There are four generator elastic supports, located at the four bases of the generator base. The active end measuring points are located in the z-direction of the generator base, namely measuring points 5, 6, 7, and 8. The corresponding passive end measuring points are located in the z-direction outside the generator elastic supports, namely measuring points 9, 10, 11, and 12.

[0087] In step S102 , the controller uses an adaptive tracking filtering algorithm to obtain vibration order ratio signals corresponding to specific orders of the speed signal in the active and passive end vibration acceleration signals as target vibration excitation and target vibration response, respectively.

[0088] In step S103, the controller calculates the current frequency response function between the target vibration excitation and the target vibration response

[0089] In step S104, the controller calculates a distortion characteristic index and a deviation direction characteristic index between the current frequency response function and the initial frequency response function. These indicators are used to measure the degree of difference and deviation direction between the vibration isolation performance of the elastic support in the current state and the initial state. The distortion characteristic index can be used to determine the degree of degradation of the vibration isolation performance of the elastic support under test, and the deviation direction characteristic index can be used to determine the direction of development of the vibration isolation performance of the elastic support under test. The initial frequency response function is the first calculated frequency response function.

[0090] In step S105 , the distortion characteristic index is fitted using time as the horizontal coordinate to obtain a distortion time trend curve.

[0091] In step S106 , the second-order difference of the distortion time trend curve is calculated, and the degradation trend of the distortion characteristic index can be determined based on the second-order difference.

[0092] In step S107, the larger the distortion characteristic index is, the more likely the elastic support body to be tested is to be affected by contamination, overheating, overcooling, ozone, etc. The development direction of the vibration isolation performance of the elastic support to be tested can be determined by combining the deviation direction characteristic index, and the degradation trend of the distortion characteristic index can be determined by combining the second-order difference, so that corresponding maintenance suggestions can be given, such as replacing the elastic support, checking the elastic support body and installation status, checking the vibration of the transmission chain, continuously monitoring the elastic support characteristic index, checking whether the elastic support body has contamination and cracks, and no intervention measures are required.

[0093] The present invention provides a method for monitoring the vibration isolation performance of an elastic support of a wind turbine generator set. The method calculates the distortion characteristic index and the deviation direction characteristic index of the elastic support to be tested based on the changes in the frequency response functions of the active and passive ends of the elastic support to be tested, fits the distortion characteristic index to obtain a distortion time trend curve, and calculates the second-order difference of the distortion time trend curve. The vibration isolation performance of the elastic support to be tested is judged based on the distortion characteristic index, a preset distortion characteristic index threshold, the deviation direction characteristic index, and the second-order difference, thereby achieving real-time and accurate monitoring of the vibration isolation performance of the elastic support. In addition, no additional complex sensing equipment is required except for the vibration sensor. The speed signal of the generator is derived from the generator set, and the system composition is simple and the cost is low. At the same time, by calculating the changes in the frequency response functions of the active and passive ends of the elastic support to be tested, the vibration transfer characteristic level of the elastic support body is monitored, which is not affected by the operating conditions of the unit and the external vibration interference of the elastic support, reduces errors, and has strong real-time performance.

[0094] In one embodiment, step S101 includes:

[0095] The vibration acceleration signal and the speed signal are obtained according to the preset sampling length, sampling frequency and sampling interval.

[0096] Specifically, the controller sets the sampling length N and sampling frequency f s And the sampling interval is T. After the unit is started, the acceleration signal y(n) of length N and the generator speed signal s(n) of the unit main control system with the same length N are obtained every T s.

[0097] In one embodiment, step S102 includes:

[0098] The Kalman tracking filter algorithm is used to obtain the target vibration excitation and target vibration response with the input shaft of the generator as the reference axis.

[0099] Specifically, the controller uses an adaptive tracking filter algorithm such as the Kalman tracking filter to extract the vibration order ratio signal x corresponding to the order p of the generator speed signal ω(n) from the vibration acceleration signal y(n) of the active and passive ends of the elastic support, with the generator input shaft as the reference axis.p (n) as the target vibration excitation and target vibration response. Accordingly, the generator elastic support monitoring extracts the 1st order (p=1) vibration order ratio signal x1(n) corresponding to the original generator rotation frequency signal 1*ω(n) / 60, and the gearbox elastic support monitoring extracts the pth order vibration order ratio signal x corresponding to the planetary gear transmission meshing frequency p*ω(n) / (60) at the torque arm. p (n). Where: p is the ratio of the planetary gear meshing frequency to the generator rotation frequency.

[0100] In one embodiment, in order to obtain the target vibration excitation and target vibration response and to more accurately determine the vibration isolation performance of the elastic support, the Kalman tracking filter algorithm is used to obtain the target vibration excitation and target vibration response with the input shaft of the generator as the reference axis, including:

[0101] Establish the observation equation:

[0102] y(n)=x(n)Θ(n)+ξ(n)

[0103]

[0104] Where n = 1, 2, 3, ..., N, Θ(n) is the modulation envelope of the vibration order ratio signal x(n), ω(m) is the speed signal, f s is a function of the sampling frequency, ξ(n) is the non-order-ratio component and noise in the original acceleration signal y(n);

[0105] The weighting factor is calculated using the following formula:

[0106]

[0107] Among them, r is the weighting factor, f H is the low-pass analysis bandwidth, f H It can be set as the maximum value of the planetary gear meshing frequency;

[0108] The minimum value of the sum of squares of non-order ratio components, noise and non-uniform terms is calculated according to the weighting factor, and the target vibration excitation and target vibration response are obtained.

[0109] Specifically, the non-order ratio component and noise ξ(n) are written in matrix form as:

[0110] y-Cx=ξ

[0111] Among them: the known matrix C is:

[0112]

[0113] The non-uniform term ε(n) is used to characterize the changes in the amplitude, frequency, and phase of the sine wave. The matrix form of the non-uniform term ε(n) can be written as:

[0114] Ax=ε

[0115] Among them: the known matrix A is the second-order Kalman tracking filter polynomial matrix:

[0116]

[0117] The square sum J of the non-order ratio component and noise ξ(n) and the non-uniform term ε(n) is:

[0118] ξ T ξ=(y T -x H C H )(y-Cx)

[0119] J=r 2 ε T ε+ξ T ξ=r 2 x T A T Ax+[(y T -x H C H )(y-Cx)]

[0120] Minimize J, that is, J with respect to x H The first-order partial derivative of is 0, so:

[0121]

[0122] The vibration order ratio signal x is obtained as:

[0123]

[0124] Therefore, the active end vibration order ratio signal x is the target vibration excitation, and the passive end vibration order ratio signal x is the target response.

[0125] In one embodiment, in order to facilitate calculation of the current frequency response function and more accurately determine the vibration isolation performance of the elastic support, step S103 includes:

[0126] The current frequency response function is calculated using the following formula:

[0127]

[0128] Where: H0(n) is the initial frequency response function; H j (n) is the current frequency response function; X 01 (n), X 02 (n), X j1 (n), X j2 (n) are x 01(n), x 02 (n), x j1 (n), x j2 (n) is the Fourier transform amplitude spectrum.

[0129] In one embodiment, in order to calculate the distortion characteristic index and the deviation direction characteristic index and more accurately determine the vibration isolation performance of the elastic support, step S104 includes:

[0130] The following formula is used to calculate the distortion characteristic index and the deviation direction characteristic index:

[0131]

[0132] Where ΔH j is the characteristic index of distortion, ΔM j It is a characteristic indicator of deviation direction.

[0133] In one embodiment, in order to calculate the second-order difference and more accurately determine the vibration isolation performance of the elastic support, step S106 includes:

[0134] The second-order difference is calculated using the following formula:

[0135] D j =ΔH j+1 -2ΔH j +ΔH j-1

[0136] Among them, D j is the second-order difference; ΔH j+1 is the distortion characteristic index at the next moment; ΔH j-1 is the distortion characteristic index of the previous moment.

[0137] Specifically, taking a single elastic support as an example, when sampling for the first time, the acceleration order ratio signal x of the active and passive ends of the elastic support is used. 01 (n), x 02 (n), calculate the initial frequency response function H0(n) of the elastic support, and use the x j1 (n), x j2 (n) The calculated frequency response function H of the elastic support in the current state j (n), and calculate the distortion characteristic index ΔH j (n) and deviation direction characteristic index ΔM j And the second-order difference D of the time curve of the distortion characteristic index.

[0138] like Figure 3 and Figure 4 As shown, Figure 3The solid line is the initial frequency response function H0, and the dotted line is the current frequency response function H j , ΔM j is the current frequency response function H j The deviation value from the initial frequency response function H0, the distortion characteristic index ΔH j Characterizes the degree of elastic support degradation, which is always positive. If the value increases, it indicates that the elastic support body may be affected by contamination, overheating, overcooling, ozone, etc., but its impact on the vibration isolation performance in the system cannot be determined. It is necessary to combine the deviation direction characteristic index ΔM j The positive or negative value of ΔM determines the development direction of vibration isolation performance. j A positive value indicates that the vibration isolation performance is reduced, ΔM j A negative value indicates that the vibration isolation performance has improved. j A positive value indicates that the distortion characteristic index is increasing rapidly and the degree of degradation is developing rapidly, such as Figure 4 The raised part; if D j A negative value indicates that the distortion characteristic index trend is stable, such as Figure 4 The concave part, Figure 4 Medium Δ max is the distortion feature index threshold.

[0139] like Figure 5 As shown, another embodiment of the present invention provides a method for monitoring vibration isolation performance of elastic supports of a wind turbine generator set, comprising:

[0140] Step S501: obtaining a vibration acceleration signal of the elastic support to be tested and a rotation speed signal of the generator;

[0141] Step S502: Using the Kalman tracking filter algorithm, obtain vibration order ratio signals corresponding to specific orders of the speed signal in the vibration acceleration signals of the driving and moving ends as target vibration excitation and target vibration response respectively;

[0142] Step S503: Calculating a current frequency response function between the target vibration excitation and the target vibration response;

[0143] Step S504: calculating a distortion characteristic index and a deviation direction characteristic index between the current frequency response function and the initial frequency response function;

[0144] Step S505: fitting the distortion characteristic index to obtain a distortion time trend curve;

[0145] Step S506: Calculating the second-order difference of the distortion time trend curve;

[0146] Step S507: If the distortion characteristic index exceeds the distortion characteristic index threshold, the deviation direction characteristic index is positive, and the second-order difference is positive, it is determined that the vibration isolation performance of the elastic support to be tested has deteriorated, the degree of degradation of the elastic support to be tested is high and the degradation degree is rapidly developing, and a prompt is given to immediately replace the elastic support to be tested;

[0147] Step S508: If the distortion characteristic index exceeds the distortion characteristic index threshold, the deviation direction characteristic index is negative, and the second-order difference is positive, it is determined that the vibration isolation performance of the elastic support to be tested is normal, or the degradation degree of the elastic support to be tested is high and rapidly progressing, and a prompt is given to check the body and installation status of the elastic support to be tested;

[0148] Step S509: If the distortion characteristic index exceeds the distortion characteristic index threshold, the deviation direction characteristic index is positive, and the second-order difference is negative, it is determined that the vibration isolation performance of the elastic support to be tested has deteriorated, the degree of degradation of the elastic support to be tested is high, and the degradation trend is stable. A prompt is given to check the elastic support to be tested, its installation status, and the vibration of the transmission chain.

[0149] Step S510: If the distortion characteristic index exceeds the distortion characteristic index threshold, the deviation direction characteristic index is negative, and the second-order difference is negative, it is determined that the vibration isolation performance of the elastic support to be tested is normal, the degree of degradation of the elastic support to be tested is high and the degradation trend is stable, and a prompt is given to check whether the body of the elastic support to be tested is contaminated and / or cracked;

[0150] Step S511: If the distortion characteristic index does not exceed the distortion characteristic index threshold, the deviation direction characteristic index is positive, and the second-order difference is positive, it is determined that the vibration isolation performance of the elastic support to be tested has deteriorated, the degree of degradation of the elastic support to be tested is low and the degradation is rapidly progressing, and a prompt is given to continuously monitor the characteristic index of the elastic support to be tested and to check the vibration of the transmission chain;

[0151] Step S512: If the distortion characteristic index does not exceed the distortion characteristic index threshold, the deviation direction characteristic index is negative, and the second-order difference is positive, it is determined that the vibration isolation performance of the elastic support to be tested is normal, the degree of degradation of the elastic support to be tested is low and the degradation degree is rapidly developing, and a prompt is given to continuously monitor the characteristic index of the elastic support to be tested;

[0152] Step S513: If the distortion characteristic index does not exceed the distortion characteristic index threshold, the deviation direction characteristic index is positive, and the second-order difference is negative, it is determined that the vibration isolation performance of the elastic support to be tested has deteriorated, the degradation degree of the elastic support to be tested is low, and the degradation trend is stable, and a prompt is given to check the vibration of the transmission chain;

[0153] Step S514: If the distortion characteristic index does not exceed the distortion characteristic index threshold, the deviation direction characteristic index is negative, and the second-order difference is negative, it is determined that the vibration isolation performance of the elastic support to be tested is normal, the degradation degree of the elastic support to be tested is low, and the degradation trend is stable, and a prompt is given that no intervention measures are required.

[0154] Specifically, the controller simultaneously obtains the vibration acceleration signal of the elastic support to be tested and the speed signal of the generator, and then executes steps S502 to S506. It then determines whether the distortion characteristic index exceeds the distortion characteristic index threshold, whether the deviation direction characteristic index is a positive value, and whether the second-order difference is a positive value. Based on the corresponding judgment results, steps S507 to S514 are executed to judge the vibration isolation performance of the elastic support to be tested, and corresponding maintenance suggestions can be given based on the judgment results, as shown in Table 1 below:

[0155] Table 1

[0156]

[0157]

[0158] In Table 1, ΔH j is the characteristic index of distortion, Δ max is the threshold value of the distortion characteristic index, ΔM j is the deviation direction characteristic index, D j is the second-order difference.

[0159] By comprehensively considering the degree to which the elastic support's state deviates from its initial state, the speed of the deviation, and the direction in which the deviation affects the vibration isolation performance, early warnings can be provided, and precise troubleshooting and maintenance strategies can be given to reduce the number and cost of routine maintenance, thereby avoiding excessive wear of transmission chain components due to elastic support damage, and even the resulting safety hazards.

[0160] It should be understood that the size of the serial numbers of each step in step S507-step S514 does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiment of the present invention.

[0161] like Figure 6 As shown, an embodiment of the present invention provides a vibration isolation performance monitoring device for elastic supports of a wind turbine generator set, comprising:

[0162] A first acquisition unit 601 is configured to acquire a vibration acceleration signal of the elastic support to be tested and a rotational speed signal of the generator, wherein the vibration acceleration signal includes a vibration acceleration signal of an active end and a vibration acceleration signal of a passive end of the elastic support to be tested;

[0163] A second acquiring unit 602 is configured to use an adaptive tracking filtering algorithm to acquire a vibration order ratio signal corresponding to a specific order of the rotational speed signal in the active-end vibration acceleration signal as a target vibration excitation of the elastic support to be tested, and to acquire a vibration order ratio signal corresponding to the specific order of the rotational speed signal in the passive-end vibration acceleration signal as a target vibration response of the elastic support to be tested;

[0164] A response function calculation unit 603 is used to calculate a current frequency response function between the target vibration excitation and the target vibration response;

[0165] The characteristic index calculation unit 604 is used to calculate the distortion characteristic index and the deviation direction characteristic index between the current frequency response function and the initial frequency response function;

[0166] A curve generating unit 605 is used to fit the distortion characteristic index to obtain a distortion time trend curve;

[0167] A difference calculation unit 606 is used to calculate the second-order difference of the distortion time trend curve;

[0168] The judging unit 607 is configured to judge the vibration isolation performance of the elastic support to be tested according to the distortion characteristic index, a preset distortion characteristic index threshold, the deviation direction characteristic index, and the second-order difference.

[0169] The present invention provides a vibration isolation performance monitoring device for an elastic support of a wind turbine generator set. The device calculates the distortion characteristic index and the deviation direction characteristic index of the elastic support to be tested based on the changes in the frequency response functions of the active and passive ends of the elastic support to be tested, fits the distortion characteristic index to obtain a distortion time trend curve, and calculates the second-order difference of the distortion time trend curve. The vibration isolation performance of the elastic support to be tested is judged based on the distortion characteristic index, a preset distortion characteristic index threshold, the deviation direction characteristic index, and the second-order difference, thereby achieving real-time and accurate monitoring of the vibration isolation performance of the elastic support. In addition, no additional complex sensing equipment is required except for the vibration sensor. The speed signal of the generator is derived from the generator set, and the system composition is simple and the cost is low. At the same time, by calculating the changes in the frequency response functions of the active and passive ends of the elastic support to be tested, the vibration transfer characteristic level of the elastic support body is monitored, which is not affected by the operating conditions of the unit and the external vibration interference of the elastic support, reduces errors, and has strong real-time performance.

[0170] In one embodiment, the first obtaining unit 601 is further configured to:

[0171] The vibration acceleration signal and the speed signal are obtained according to the preset sampling length, sampling frequency and sampling interval.

[0172] Specifically, the controller sets the sampling length N and sampling frequency f s And the sampling interval is T. After the unit is started, the acceleration signal y(n) of length N and the generator speed signal s(n) of the unit main control system with the same length N are obtained every T s.

[0173] In one embodiment, the second obtaining unit 602 is further configured to:

[0174] The Kalman tracking filter algorithm is used to obtain the target vibration excitation and target vibration response with the input shaft of the generator as the reference axis.

[0175] Specifically, the controller uses an adaptive tracking filter algorithm such as the Kalman tracking filter to extract the vibration order ratio signal x corresponding to the order p of the generator speed signal ω(n) from the vibration acceleration signal y(n) of the active and passive ends of the elastic support, with the generator input shaft as the reference axis. p (n) as the target vibration excitation and target vibration response. Accordingly, the generator elastic support monitoring extracts the 1st order (p=1) vibration order ratio signal x1(n) corresponding to the original generator rotation frequency signal 1*ω(n) / 60, and the gearbox elastic support monitoring extracts the pth order vibration order ratio signal x corresponding to the planetary gear transmission meshing frequency p*ω(n) / (60) at the torque arm. p (n). Where: p is the ratio of the planetary gear meshing frequency to the generator rotation frequency.

[0176] In one embodiment, in order to obtain the target vibration excitation and the target vibration response and to more accurately determine the vibration isolation performance of the elastic support, the second obtaining unit 602 is further configured to:

[0177] Establish the observation equation:

[0178] y(n)=x(n)Θ(n)+ξ(n)

[0179]

[0180] Where n = 1, 2, 3, ..., N, Θ(n) is the modulation envelope of the vibration order ratio signal x(n), ω(m) is the speed signal, f s is a function of the sampling frequency, ξ(n) is the non-order-ratio component and noise in the original acceleration signal y(n);

[0181] The weighting factor is calculated using the following formula:

[0182]

[0183] Among them, r is the weighting factor, f H is the low-pass analysis bandwidth, f HIt can be set as the maximum value of the planetary gear meshing frequency;

[0184] The minimum value of the sum of squares of non-order ratio components, noise and non-uniform terms is calculated according to the weighting factor, and the target vibration excitation and target vibration response are obtained.

[0185] Specifically, the non-order ratio component and noise ξ(n) are written in matrix form as:

[0186] y-Cx=ξ

[0187] Among them: the known matrix C is:

[0188]

[0189] The non-uniform term ε(n) is used to characterize the changes in the amplitude, frequency, and phase of the sine wave. The matrix form of the non-uniform term ε(n) can be written as:

[0190] Ax=ε

[0191] Among them: the known matrix A is the second-order Kalman tracking filter polynomial matrix:

[0192]

[0193] The square sum J of the non-order ratio component and noise ξ(n) and the non-uniform term ε(n) is:

[0194] ξ T ξ=(y T -x H C H )(y-Cx)

[0195] J=r 2 ε T ε+ξ T ξ=r 2 x T A T Ax+[(y T -x H C H )(y-Cx)]

[0196] Minimize J, that is, J with respect to x H The first-order partial derivative of is 0, so:

[0197]

[0198] The vibration order ratio signal x is obtained as:

[0199]

[0200] Therefore, the active end vibration order ratio signal x is the target vibration excitation, and the passive end vibration order ratio signal x is the target response.

[0201] In one embodiment, in order to calculate the current frequency response function and more accurately determine the vibration isolation performance of the elastic support, the response function calculation unit 603 is further configured to:

[0202] The current frequency response function is calculated using the following formula:

[0203]

[0204] Where: H0(n) is the initial frequency response function; H j (n) is the current frequency response function; X 01 (n), X 02 (n), X j1 (n), X j2 (n) are x 01 (n), x 02 (n), x j1 (n), x j2 (n) is the Fourier transform amplitude spectrum.

[0205] In one embodiment, in order to calculate the distortion characteristic index and the deviation direction characteristic index and more accurately determine the vibration isolation performance of the elastic support, the characteristic index calculation unit 604 includes:

[0206] The following formula is used to calculate the distortion characteristic index and the deviation direction characteristic index:

[0207]

[0208] Where ΔH j is the characteristic index of distortion, ΔM j It is a characteristic indicator of deviation direction.

[0209] In one embodiment, in order to facilitate calculation of the second-order difference and more accurately determine the vibration isolation performance of the elastic support, the difference calculation unit 606 is further configured to:

[0210] The second-order difference is calculated using the following formula:

[0211] D j =ΔH j+1 -2ΔH j +ΔH j-1

[0212] Among them, D j is the second-order difference; ΔH j+1 is the distortion characteristic index at the next moment; ΔH j-1 is the distortion characteristic index of the previous moment.

[0213] Specifically, taking a single elastic support as an example, when sampling for the first time, the acceleration order ratio signal x of the active and passive ends of the elastic support is used. 01 (n), x 02 (n), calculate the initial frequency response function H0(n) of the elastic support, and use the x j1 (n), x j2 (n) The calculated frequency response function H of the elastic support in the current state j (n), and calculate the distortion characteristic index ΔH j (n) and deviation direction characteristic index ΔM j And the second-order difference D of the time curve of the distortion characteristic index.

[0214] In one embodiment, the determining unit 607 is further configured to:

[0215] If the distortion characteristic index exceeds the distortion characteristic index threshold, the deviation direction characteristic index is positive, and the second-order difference is positive, it is determined that the vibration isolation performance of the elastic support to be tested has deteriorated, the degree of degradation of the elastic support to be tested is high and the degradation degree is rapidly developing, and a prompt is given to immediately replace the elastic support to be tested;

[0216] If the distortion characteristic index exceeds the distortion characteristic index threshold, the deviation direction characteristic index is negative, and the second-order difference is positive, it is judged that the vibration isolation performance of the elastic support to be tested is normal, and the degradation degree of the elastic support to be tested is high and the degradation degree is rapidly developing. It is suggested to check the body and installation status of the elastic support to be tested;

[0217] If the distortion characteristic index exceeds the distortion characteristic index threshold, the deviation direction characteristic index is positive, and the second-order difference is negative, it is judged that the vibration isolation performance of the elastic support to be tested has deteriorated, the degree of degradation of the elastic support to be tested is high, and the degradation trend is stable. It is suggested to check the elastic support to be tested, its installation status, and the vibration of the transmission chain;

[0218] If the distortion characteristic index exceeds the distortion characteristic index threshold, the deviation direction characteristic index is negative, and the second-order difference is negative, it is judged that the vibration isolation performance of the elastic support to be tested is normal, the degradation degree of the elastic support to be tested is high and the degradation trend is stable, and it is suggested to check whether the body of the elastic support to be tested is contaminated and / or cracked;

[0219] If the distortion characteristic index does not exceed the distortion characteristic index threshold, the deviation direction characteristic index is positive, and the second-order difference is positive, it is judged that the vibration isolation performance of the elastic support to be tested has deteriorated, the degradation degree of the elastic support to be tested is low and the degradation degree is rapidly developing, and it is suggested to continuously monitor the characteristic index of the elastic support to be tested and check the vibration of the transmission chain;

[0220] If the distortion characteristic index does not exceed the distortion characteristic index threshold, the deviation direction characteristic index is negative, and the second-order difference is positive, it is judged that the vibration isolation performance of the elastic support to be tested is normal, the degradation degree of the elastic support to be tested is low and the degradation degree is rapidly developing, and it is suggested to continuously monitor the characteristic index of the elastic support to be tested;

[0221] If the distortion characteristic index does not exceed the distortion characteristic index threshold, the deviation direction characteristic index is positive, and the second-order difference is negative, it is determined that the vibration isolation performance of the elastic support to be tested has deteriorated. The degradation degree of the elastic support to be tested is low and the degradation trend is stable, prompting the vibration of the transmission chain to be checked.

[0222] If the distortion characteristic index does not exceed the distortion characteristic index threshold, the deviation direction characteristic index is negative, and the second-order difference is negative, it is judged that the vibration isolation performance of the elastic support to be tested is normal, the degradation degree of the elastic support to be tested is low, and the degradation trend is stable, indicating that no intervention measures are required.

[0223] By comprehensively considering the degree to which the elastic support's state deviates from its initial state, the speed of the deviation, and the direction in which the deviation affects the vibration isolation performance, early warnings can be provided, and precise troubleshooting and maintenance strategies can be given to reduce the number and cost of routine maintenance, thereby avoiding excessive wear of transmission chain components due to elastic support damage, and even the resulting safety hazards.

[0224] The above embodiments are only used to illustrate the technical solutions of the embodiments of the present invention, rather than to limit them. Although the embodiments of the present invention have been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for monitoring the vibration isolation performance of an elastic support of a wind turbine generator system, characterized in that: include: Acquire a vibration acceleration signal of the elastic support to be tested and a speed signal of the generator, wherein the vibration acceleration signal includes a vibration acceleration signal of an active end and a vibration acceleration signal of a passive end of the elastic support to be tested; Using an adaptive tracking filtering algorithm, obtaining a vibration order ratio signal corresponding to a specific order of the rotational speed signal in the active-end vibration acceleration signal as a target vibration excitation of the elastic support to be tested, and obtaining a vibration order ratio signal corresponding to the specific order of the rotational speed signal in the passive-end vibration acceleration signal as a target vibration response of the elastic support to be tested; calculating a current frequency response function between the target vibration excitation and the target vibration response; Calculating a distortion characteristic index and a deviation direction characteristic index between the current frequency response function and the initial frequency response function; Fitting the distortion characteristic index to obtain a distortion time trend curve; Calculating the second-order difference of the distortion time trend curve; The vibration isolation performance of the elastic support to be tested is determined according to the distortion characteristic index, the preset distortion characteristic index threshold, the deviation direction characteristic index and the second-order difference.

2. The method for monitoring vibration isolation performance of elastic supports of wind turbines according to claim 1, characterized in that: The step of obtaining the vibration acceleration signal of the elastic support to be tested and the rotation speed signal of the generator includes: The vibration acceleration signal and the rotation speed signal are acquired according to a preset sampling length, sampling frequency and sampling interval.

3. The vibration isolation performance monitoring method of the elastic support of a wind turbine according to claim 2, characterized in that: The method of using an adaptive tracking filtering algorithm to obtain a vibration order ratio signal corresponding to a specific order of the rotational speed signal in the active end vibration acceleration signal as a target vibration excitation of the elastic support to be tested, and obtaining a vibration order ratio signal corresponding to the specific order of the rotational speed signal in the passive end vibration acceleration signal as a target vibration response of the elastic support to be tested, includes: The target vibration excitation and the target vibration response are obtained by using a Kalman tracking filter algorithm and taking the input shaft of the generator as a reference axis.

4. The method for monitoring vibration isolation performance of elastic supports of wind turbines according to claim 3, characterized in that: The method of using a Kalman tracking filter algorithm to obtain the target vibration excitation and the target vibration response with the input shaft of the generator as a reference axis includes: Establish the observation equation: y(n)=x(n)Θ(n)+ξ(n) Where n = 1, 2, 3, ..., N, Θ(n) is the modulation envelope of the vibration order ratio signal x(n), ω(m) is the speed signal, f s is a function of the sampling frequency, ξ(n) is the non-order-ratio component and noise in the original acceleration signal y(n); The weighting factor is calculated using the following formula: Among them, r is the weighting factor, f H is the low-pass analysis bandwidth; The minimum value of the sum of squares of the non-order ratio component, noise, and non-consistent term is calculated according to the weighting factor to obtain the target vibration excitation and the target vibration response.

5. The method for monitoring vibration isolation performance of elastic supports of wind turbines according to claim 1, characterized in that: The calculating a current frequency response function between the target vibration excitation and the target vibration response includes: The current frequency response function is calculated using the following formula: Where: H0(n) is the initial frequency response function; H j (n) is the current frequency response function; X 01 (n), X 02 (n), X j1 (n), X j2 (n) are x 01 (n), x 02 (n), x j1 (n), x j2 (n) is the Fourier transform amplitude spectrum.

6. The method for monitoring vibration isolation performance of elastic supports of wind turbines according to claim 5, characterized in that: The calculating of the distortion characteristic index and the deviation direction characteristic index between the current frequency response function and the initial frequency response function includes: The distortion characteristic index and the deviation direction characteristic index are calculated using the following formula: Where ΔH j is the characteristic index of the distortion degree, ΔM j is the deviation direction characteristic indicator.

7. The method for monitoring vibration isolation performance of elastic supports of wind turbines according to claim 6, characterized in that: The calculating of the second-order difference of the distortion time trend curve includes: The second-order difference is calculated using the following formula: D j =ΔH j+1 -2ΔH j +ΔH j-1 Among them, D j is the second-order difference; ΔH j+1 is the distortion characteristic index at the next moment; ΔH j-1 is the distortion characteristic index of the previous moment.

8. The method for monitoring vibration isolation performance of elastic supports of a wind turbine generator set according to any one of claims 1 to 7, wherein: The step of determining the vibration isolation performance of the elastic support to be tested based on the distortion characteristic index, the preset distortion characteristic index threshold, the deviation direction characteristic index, and the second-order difference includes: If the distortion characteristic index exceeds the distortion characteristic index threshold, the deviation direction characteristic index is positive, and the second-order difference is positive, it is determined that the vibration isolation performance of the elastic support to be tested has deteriorated, and the degree of degradation of the elastic support to be tested is high and rapidly progressing; If the distortion characteristic index exceeds the distortion characteristic index threshold, the deviation direction characteristic index is a negative value, and the second-order difference is a positive value, it is determined that the vibration isolation performance of the elastic support to be tested is normal, and the degree of degradation of the elastic support to be tested is high and the degree of degradation is rapidly developing; If the distortion characteristic index exceeds the distortion characteristic index threshold, the deviation direction characteristic index is a positive value, and the second-order difference is a negative value, it is determined that the vibration isolation performance of the elastic support to be tested has deteriorated, and the degradation degree of the elastic support to be tested is high and the degradation trend is stable; If the distortion characteristic index exceeds the distortion characteristic index threshold, the deviation direction characteristic index is a negative value, and the second-order difference is a negative value, it is determined that the vibration isolation performance of the elastic support to be tested is normal, the degradation degree of the elastic support to be tested is high, and the degradation trend is stable; If the distortion characteristic index does not exceed the distortion characteristic index threshold, the deviation direction characteristic index is positive, and the second-order difference is positive, it is determined that the vibration isolation performance of the elastic support to be tested has deteriorated, and the degree of degradation of the elastic support to be tested is low and the degree of degradation is rapidly developing; If the distortion characteristic index does not exceed the distortion characteristic index threshold, the deviation direction characteristic index is a negative value, and the second-order difference is a positive value, it is determined that the vibration isolation performance of the elastic support to be tested is normal, and the degradation degree of the elastic support to be tested is low and the degradation degree is rapidly developing; If the distortion characteristic index does not exceed the distortion characteristic index threshold, the deviation direction characteristic index is a positive value, and the second-order difference is a negative value, it is determined that the vibration isolation performance of the elastic support to be tested has deteriorated, and the degradation degree of the elastic support to be tested is low and the degradation trend is stable; If the distortion characteristic index does not exceed the distortion characteristic index threshold, the deviation direction characteristic index is a negative value, and the second-order difference is a negative value, it is judged that the vibration isolation performance of the elastic support to be tested is normal, the degradation degree of the elastic support to be tested is low, and the degradation trend is stable.

9. The method for monitoring vibration isolation performance of elastic supports of wind turbines according to claim 8, characterized in that: The vibration isolation performance of the elastic support to be tested is determined according to the distortion characteristic index, the preset distortion characteristic index threshold, the deviation direction characteristic index, and the second-order difference, and then further includes: If it is determined that the vibration isolation performance of the elastic support to be tested has deteriorated, the degree of degradation of the elastic support to be tested is high and the degradation degree is rapidly developing, prompting to immediately replace the elastic support to be tested; If it is determined that the vibration isolation performance of the elastic support to be tested is normal, and the deterioration degree of the elastic support to be tested is high and the deterioration degree is rapidly developing, a prompt is given to check the body and installation status of the elastic support to be tested; If it is determined that the vibration isolation performance of the elastic support to be tested has deteriorated, the degree of degradation of the elastic support to be tested is high and the degradation trend is stable, a prompt is given to check the body, installation status and transmission chain vibration of the elastic support to be tested; If it is determined that the vibration isolation performance of the elastic support to be tested is normal, and the degradation degree of the elastic support to be tested is high and the degradation trend is stable, it is suggested to check whether the body of the elastic support to be tested is contaminated and / or cracked; If it is determined that the vibration isolation performance of the elastic support to be tested has deteriorated, and the degree of degradation of the elastic support to be tested is low and rapidly progressing, it is suggested to continuously monitor the characteristic indicators of the elastic support to be tested and to check the vibration of the transmission chain; If it is determined that the vibration isolation performance of the elastic support to be tested is normal, and the degradation degree of the elastic support to be tested is low and the degradation degree is rapidly developing, it is prompted to continuously monitor the characteristic indicators of the elastic support to be tested; If it is determined that the vibration isolation performance of the elastic support to be tested has deteriorated, the degree of degradation of the elastic support to be tested is low and the degradation trend is stable, it is suggested to check the vibration of the transmission chain; If it is determined that the vibration isolation performance of the elastic support to be tested is normal, the degradation degree of the elastic support to be tested is low and the degradation trend is stable, it is suggested that no intervention measures are required.

10. A vibration isolation performance monitoring device for elastic supports of a wind turbine generator set, characterized in that: include: a first acquiring unit, configured to acquire a vibration acceleration signal of the elastic support to be tested and a rotational speed signal of the generator, wherein the vibration acceleration signal includes a vibration acceleration signal of an active end and a vibration acceleration signal of a passive end of the elastic support to be tested; a second acquiring unit, configured to acquire, by using an adaptive tracking filtering algorithm, a vibration order ratio signal corresponding to a specific order of the rotational speed signal in the active-end vibration acceleration signal as a target vibration excitation of the elastic support to be tested, and to acquire a vibration order ratio signal corresponding to the specific order of the rotational speed signal in the passive-end vibration acceleration signal as a target vibration response of the elastic support to be tested; a response function calculation unit, configured to calculate a current frequency response function between the target vibration excitation and the target vibration response; a characteristic index calculation unit, configured to calculate a distortion characteristic index and a deviation direction characteristic index between the current frequency response function and the initial frequency response function; A curve generating unit, configured to fit the distortion characteristic index to obtain a distortion time trend curve; A difference calculation unit, used to calculate the second-order difference of the distortion time trend curve; A judging unit is configured to judge the vibration isolation performance of the elastic support to be tested based on the distortion characteristic index, a preset distortion characteristic index threshold, the deviation direction characteristic index, and the second-order difference.

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