Disclosure of Invention
Based on the above, the invention aims to provide a fault diagnosis method for a variable pitch system of a wind driven generator, which can diagnose the cause of the fault of a wind turbine and locate the fault position.
A fault diagnosis method for a pitch system of a wind driven generator comprises the following steps: step 1: acquiring historical operating data of an SCADA system of the wind driven generator; step 2: constructing a fault characteristic model by using historical operating data of the SCADA system; and step 3: constructing a fault diagnosis model by using the fault feature model; and 4, step 4: acquiring real-time fault alarm data of an SCADA system of the wind driven generator, inputting the real-time fault alarm data into a fault characteristic model, and calculating to acquire real-time fault characteristics; and 5: and (4) inputting the real-time fault characteristics obtained in the step (4) into the fault diagnosis model to obtain a fault diagnosis result.
According to the fault diagnosis method for the variable pitch system of the wind driven generator, the fault characteristics are extracted by using the wind driven generator operation data measured by the SCADA system and the fault characteristics are input into the fault model to complete fault diagnosis, so that the real-time diagnosis of the fault reason and the fault position of the wind driven generator is realized.
Further, in step 1, the historical operating data of the SCADA system includes: the wind power generator comprises one or more of average wind speed outside a nacelle of the wind power generator, wind direction, pitch angles of first to third blades of the wind power generator, rotating speed of a low-speed shaft, active power of the generator, voltage and current of a variable pitch motor, temperature of the variable pitch motor, temperature of a blade converter, voltage of a variable pitch battery, oil pressure at an outlet of a variable pitch bearing grease pump and oil pressure at an outlet of the variable pitch gear grease pump.
Further, the method for extracting the fault features comprises the following steps:
the method for constructing the fault feature model comprises the following steps:
1) constructing a theoretical deviation fault characteristic model of the pitch angle:
the pitch angle data of the blades of the wind driven generator comprise pitch angle data measured by an encoder A
And B encoder data measured by the encoder
Acquiring a group of average wind speed data in historical operation of a fan, and acquiring each average wind speed data
The following equations are substituted, respectively, to solve for a set of corresponding pitch angles β:
wherein rho is air density, η is transmission efficiency, R is wind wheel diameter, P is rated power of the wind driven generator, c
1-c
8Is the characteristic coefficient of the wind wheel, lambda
iThe tip speed of the ith blade is the tip speed of the ith blade, and lambda is the tip speed ratio of the wind wheel;
at the set of average wind speeds
Is independent variable, and the calculated group of pitch angles β are used as dependent variables, and fitting is carried out by a least square method polynomial to obtain a theoretical value β of the pitch angle
thThe calculation formula of (2):
wherein,
the rated wind speed of the wind driven generator;
using theoretical value of pitch angle β
thConstructing theoretical deviation value of pitch angle
The pitch angle theoretical deviation fault characteristic model is taken as a calculation model of (1):
where Δ β is the pitch angle absolute deviation limit,
the data of the pitch angle measured by the ith encoder A is obtained;
in the same way, the method for preparing the composite material,
where Δ β is the pitch angle absolute deviation limit,
the data of the pitch angle measured by the ith B encoder is obtained;
and/or
2) Constructing a low-speed shaft rotating speed fault characteristic model:
the low-speed shaft rotating speed fault characteristic model comprises a wind wheel rotating speed relative deviation calculation model and a wind wheel rotating speed relative fluctuation calculation model;
constructing a wind wheel rotating speed relative deviation calculation model:
wherein, δ n
lsIs the relative deviation of the rotational speed of the rotor, n
lsFor the low-speed shaft speed data,
the theoretical value of the rotating speed of the low-speed shaft meets the following formula:
wherein n is
0Is the rated rotating speed of the low-speed shaft,
for the wind generator to cut into the wind speed,
cutting wind speed for the wind driven generator;
constructing a wind wheel rotating speed relative fluctuation calculation model:
wherein, δ Δ n
msIs the relative fluctuation value of the rotating speed of the wind wheel,
is the maximum value in the low-speed shaft speed data for several seconds,
is the minimum value in the low-speed shaft speed data within seconds; preferably, the first and second electrodes are formed of a metal,
is the maximum value in the low-speed shaft speed data for 60 seconds,
is the minimum value in the low speed shaft speed data for 60; and/or
3) Constructing a pitch angle deviation fault characteristic model:
the pitch angle data of the blades of the wind driven generator further comprise pitch angle data measured by three B encoders
The pitch angle deviation fault characteristic model comprises a pitch angle relative deviation calculation model and a pitch angle absolute deviation calculation model;
constructing a pitch angle relative deviation calculation model of the first blade to the third blade of the wind driven generator:
wherein,
the average pitch angle of the data is measured for three a encoders,
the average pitch angle of the data is measured for the three B encoders,
for the pitch angle relative deviation from the a encoder measurement data,
the relative deviation of the pitch angle obtained by the data measured by the B encoder;
constructing a pitch angle absolute deviation calculation model of the first blade to the third blade of the wind driven generator:
and/or
4) Constructing a fault characteristic model of the variable-pitch battery pack:
wherein, Vbp0Is changed into a first pitch to a third pitchThe normal voltage of the battery pack is set,
Vbp1-Vbp3the voltage data of the first to the third pitch-variable batteries included in the voltage number of the pitch-variable batteries is delta Vbp1-δVbp3The voltage relative deviation of the first variable-pitch battery pack, the second variable-pitch battery pack and the third variable-pitch battery pack is obtained; and/or
5) Constructing a converter temperature fault characteristic model delta t of a variable pitch motorf cbi:
Wherein, tf cb0Is the upper temperature limit, t, of the converterf cbiFor said converter temperature data, δ tf cbiThe temperature deviation of a current transformer of the ith variable pitch motor is obtained; and/or
6) Constructing a temperature deviation fault characteristic model of the variable pitch motor:
the temperature data of the variable pitch motors comprise temperature data t of the first to third variable pitch motorsm1-tm3;
The temperature deviation fault characteristic model of the variable pitch motor is as follows:
wherein, tm0For the temperature deviation limit, δ t, of the pitch motorm1-δtm3The temperature deviation of the first variable pitch motor, the second variable pitch motor and the third variable pitch motor is obtained; and/or
7) Constructing a variable pitch motor current fault characteristic model:
the variable pitch motor current data comprise current data I of the first to third variable pitch motorsm1-Im3;
The current fault characteristic model of the variable pitch motor is as follows:
wherein, Im0Is the current deviation limit value, delta, of the pitch motorIm1-δIm3The current deviation of the first variable pitch motor, the second variable pitch motor and the third variable pitch motor is obtained; and/or
8) Constructing a variable pitch motor rotating speed characteristic model:
the variable pitch motor rotating speed data comprises rotating speed data n of a first variable pitch motor, a second variable pitch motor, a third variable pitch motor and a fourth variable pitch motorm1-nm3;
The variable pitch motor rotating speed characteristic model is as follows:
wherein n is
m0Is the average rotating speed of a variable pitch motor and meets the requirement
δn
m1-δn
m3The rotating speed deviation of the first variable pitch motor, the second variable pitch motor and the third variable pitch motor is obtained;
and/or
9) Constructing a fault characteristic model of the variable-pitch bearing grease pump:
wherein,
respectively is the upper limit value and the lower limit value of the pressure at the outlet of the ith variable-pitch bearing grease pump, p
bgpiFor the ith variable pitch bearing grease pump outlet pressure data,
and
the pressure upper limit deviation and the pressure lower limit deviation of the ith variable pitch shaft oil pump are obtained;
and/or
10) Constructing a pressure fault characteristic model of an outlet of a variable pitch gear grease pump:
wherein,
respectively is the upper limit value and the lower limit value of the pressure at the outlet of the ith variable pitch gear grease pump, p
ggpiFor the ith pitch gear grease pump outlet pressure data,
and
and the pressure upper limit deviation and the pressure lower limit deviation of the ith variable pitch gear grease pump.
Further, in step 3, the method for constructing the fault diagnosis model includes the following steps:
1) constructing a fault diagnosis model of the variable pitch gearbox:
when the current deviation of the ith variable pitch motor and the temperature deviation of the ith variable pitch motor meet the following conditions:
the fault of the ith variable pitch gearbox can be judged;
if the upper limit deviation and the lower limit deviation of the ith variable pitch gear grease pump meet the following requirements at the same time:
or
It can be further judged that: an ith pitch gearbox fault; and/or
2) Constructing a fault diagnosis model of the variable-pitch bearing:
the following equation holds:
the current deviation of the first to the third variable pitch motors satisfies
And the temperature deviation of the first to the third variable pitch motors meets the requirement
And the upper limit deviation and the lower limit deviation of the first to third variable pitch shaft oil pumps meet the conditions:
or
And the fault of the variable pitch bearing can be judged.
Further, in step 3, the method for constructing the fault diagnosis model further includes constructing a fault diagnosis model of a mechanical component of the pitch system:
1) constructing a fault diagnosis model of the variable pitch gearbox:
when the current deviation of the ith variable pitch motor and the temperature deviation of the ith variable pitch motor meet the following conditions:
the fault of the ith variable pitch gearbox can be judged;
if the upper limit deviation and the lower limit deviation of the ith variable pitch gear grease pump meet the following requirements at the same time:
or
It can be further judged that: an ith pitch gearbox fault; and/or
2) Constructing a fault diagnosis model of the variable-pitch bearing:
the following equation holds:
the current deviation of the first to the third variable pitch motors satisfies
And the temperature deviation of the first to the third variable pitch motors meets the requirement
And the upper limit deviation and the lower limit deviation of the first to third variable pitch shaft oil pumps meet the conditions:
or
And the fault of the variable pitch bearing can be judged.
Further, in step 3, the method for constructing the fault diagnosis model further includes constructing a fault diagnosis model of a control system of the pitch system:
1) constructing a variable pitch angle difference fault diagnosis model:
when the relative deviation of the pitch angle and the deviation of the pitch angle delta βbiSatisfies the following formula:
and is
Judging that the B encoder of the ith blade has a fault;
relative and absolute Pitch Angle deviations Δ βbiSatisfies the following formula:
and is
Judging the failure of an encoder A of the ith blade, wherein a is the allowable error of the variable pitch angle;
and/or
2) Constructing a blade limit switch trigger early fault diagnosis model:
if the pitch angle relative deviation and blade angle satisfy the following equation:
the fault cause can be diagnosed as early triggering of the paddle limit switch; and/or
3) Constructing a high-temperature fault diagnosis model of the variable pitch motor:
if: variable pitch motor temperature deviation deltatmiThe temperature of the variable-pitch motor is more than or equal to 10.0 percent, and the high-temperature fault of the variable-pitch motor can be judged to occur in the ith blade;
if the temperature deviation of the variable pitch motor and the current deviation of the variable pitch motor meet the following conditions:
the high-temperature fault of the pitch motor of the ith blade can be judged, and the fault is mostly caused by the fault of the pitch gearbox; and/or
4) Constructing a fault diagnosis model for overhigh rotating speed of a variable pitch motor:
if the following two equations hold:
the rotating speed deviation of the variable pitch motor meets the requirement
And the rotating speed of the variable pitch motor meets
The fault that the rotating speed of the variable pitch motor is too high can be judged, and the fault is mostly caused by the fault of an A encoder, wherein a is the allowable rotating speed deviation of the wind driven generator; and/or
5) Constructing a variable pitch failure diagnosis model:
the following equation holds:
the relative deviation of the pitch angle measured by the A encoder satisfies
And the relative deviation of the pitch angle measured by the B encoder satisfies
And the theoretical deviation of the pitch angles of the first to third blades satisfies
Then the occurrence of a pitch failure fault can be judged; and/or
6) Constructing a pitch system signal transmission fault diagnosis model:
the following equation holds:
the relative deviation of the rotating speed of the low-speed shaft meets delta nlsNot less than 10.0% and the rotation speed deviation of the variable pitch motor meets delta nmsAnd if the pitch control signal transmission fault is more than or equal to 10.0 percent, the occurrence of the pitch control signal transmission fault can be judged.
Further, in step 5, when the real-time fault characteristics are input into the fault diagnosis model, firstly, the real-time fault characteristics are input into the fault diagnosis model of the variable pitch power system and the fault diagnosis model of the mechanical component of the variable pitch system, and the fault type of the real-time fault characteristics is judged; and if the real-time fault characteristics are judged not to belong to the two types of fault models, inputting the real-time fault characteristics into a control system fault diagnosis model of the variable pitch system for diagnosis.
Further, in step 5, the fault diagnosis result includes a fault reason and a fault location.
Further, in step 2, the historical operating data is subjected to preprocessing and then fault feature extraction is carried out; the preprocessing comprises denoising, filtering, translating and amplifying the electric signals of the historical operating data to obtain standard operating data with the amplitude range of 0-5V.
Further, in the steps 1-5, the data collector is adopted to obtain the wind driven generator operation data measured by all the SCADA systems, and the computer is adopted to store and complete data storage, fault diagnosis and result display.
For a better understanding and practice, the invention is described in detail below with reference to the accompanying drawings.
Detailed Description
According to the fault diagnosis method for the variable pitch system of the wind driven generator, disclosed by the invention, the fault characteristics are extracted and the fault diagnosis model of each part of the variable pitch system is constructed by utilizing various historical operating data of the wind driven generator, which are acquired by the SCADA system, so that the specific fault reason and the fault position of the variable pitch system of the wind driven generator can be accurately judged in the real-time operating process of the wind driven generator.
Specifically, the fault diagnosis method for the pitch system of the wind driven generator comprises the following steps:
step 1: acquiring historical operating data of an SCADA system of the wind driven generator, wherein the historical operating data comprises average wind speed and wind direction outside a cabin of the wind driven generator, a pitch angle of a blade of the wind driven generator, the rotating speed of a low-speed shaft of a variable pitch system, active power of the generator, voltage and current of a variable pitch motor, the temperature of the variable pitch motor, the temperature of a blade converter, the voltage of a variable pitch battery, the oil pressure of an outlet of a variable pitch bearing grease pump and the oil pressure of an outlet of a variable pitch; the pitch angle data of the blades of the wind driven generator comprise encoder data obtained by measuring a pitch angle data of an encoder A and an encoder B.
Wherein the paddle of the wind driven generator bladeThe pitch angle data comprises pitch angle data measured by an A encoder
And B encoder data measured by the encoder
The variable pitch battery voltage number comprises voltage data V of the first to third variable pitch batteries
bp1-V
bp3(ii) a The blade converter temperature data comprises converter temperature data t of the first to third variable pitch motors
f cb1-t
f cb3(ii) a The temperature data of the variable pitch motors comprise temperature data t of the first to third variable pitch motors
m1-t
m3(ii) a The variable pitch motor current data comprise current data I of the first to third variable pitch motors
m1-I
m3(ii) a The variable pitch motor rotating speed data comprises rotating speed data n of a first variable pitch motor, a second variable pitch motor, a third variable pitch motor and a fourth variable pitch motor
m1-n
m3(ii) a The oil pressure at the outlet of the variable-pitch bearing grease pump comprises
Step 2: firstly, preprocessing the historical operating data: denoising, filtering, translating and amplifying the measurement signal of each historical operation data to obtain standard operation data with the amplitude range of 0-5V; and then, constructing a fault characteristic model of each position of the wind driven generator variable pitch system by using the standard operation data. The method for constructing the fault characteristic model specifically comprises the following steps:
1) constructing a theoretical deviation fault characteristic model of the pitch angle:
acquiring a group of average wind speed data in historical operation of a fan, and acquiring each average wind speed data
The following equations are substituted, respectively, to solve for a set of corresponding pitch angles β:
wherein rho is air density, η is transmission efficiency, R is wind wheel diameter, P is rated power of the wind driven generator, c
1-c
8Is the characteristic coefficient of the wind wheel, lambda
iThe tip speed of the ith blade is the tip speed of the ith blade, and lambda is the tip speed ratio of the wind wheel;
at the set of average wind speeds
Is independent variable, and the calculated group of pitch angles β are used as dependent variables, and fitting is carried out by a least square method polynomial to obtain the theoretical value β of the pitch angle
thExpression (c):
wherein,
the rated wind speed of the wind driven generator;
using theoretical value of pitch angle β
thConstructing theoretical deviation value of pitch angle
The pitch angle theoretical deviation fault characteristic model is taken as a calculation model of (1):
where Δ β is the pitch angle absolute deviation limit,
the data of the pitch angle measured by the ith encoder A is obtained;
where Δ β is the pitch angle absolute deviation limit,
is the pitch angle data measured by the ith B encoder. When the blade pitch angle is normal, the theoretical deviation value of the pitch angle
Theoretical offset value of pitch angle
Is one of the conditions that the pitch angle is abnormal.
2) Constructing a low-speed shaft rotating speed fault characteristic model:
the low-speed shaft rotating speed fault characteristic model comprises a wind wheel rotating speed relative deviation calculation model and a wind wheel rotating speed relative fluctuation calculation model;
constructing a wind wheel rotating speed relative deviation calculation model:
wherein, δ n
lsIs the relative deviation of the rotational speed of the rotor, n
lsFor the low-speed shaft speed data,
the theoretical value of the rotating speed of the low-speed shaft meets the following formula:
wherein n is
0Is the rated rotating speed of the low-speed shaft,
for the wind generator to cut into the wind speed,
cutting wind speed for the wind driven generator;
constructing a wind wheel rotating speed relative fluctuation calculation model:
wherein, δ Δ n
msIs the relative fluctuation value of the rotating speed of the wind wheel,
is the maximum value in the low-speed shaft speed data in n seconds,
is the minimum value in the low-speed shaft speed data within n seconds. Preferably, the first and second electrodes are formed of a metal,
is the maximum value in the low-speed shaft speed data for 60 seconds,
is the minimum value in the low speed shaft speed data for 60 seconds.
3) Constructing a pitch angle deviation fault characteristic model:
the pitch angle deviation fault characteristic model comprises a pitch angle relative deviation calculation model and a pitch angle absolute deviation calculation model;
constructing a pitch angle relative deviation calculation model of the first blade to the third blade of the wind driven generator:
wherein,
the average pitch angle of the data is measured for three a encoders,
the average pitch angle of the data is measured for the three B encoders,
for the pitch angle relative deviation from the a encoder measurement data,
the relative deviation of the pitch angle obtained by the data measured by the B encoder;
constructing a pitch angle absolute deviation calculation model of the first blade to the third blade of the wind driven generator:
4) constructing a fault characteristic model of the variable-pitch battery pack:
the variable pitch battery voltage number comprises voltage data V of the first to third variable pitch batteriesbp1-Vbp3,
The fault characteristic model of the variable-pitch battery pack is as follows:
wherein, Vbp0Is the normal voltage of the first to third pitch battery packs,
δVbp1-δVbp3and the voltage relative deviation of the first variable pitch battery pack, the second variable pitch battery pack and the third variable pitch battery pack.
5) Constructing a converter temperature fault characteristic model delta t of a variable pitch motorf cbi:
Wherein, tf cb0Is the upper temperature limit, t, of the converterf cbiFor the converter temperature data of the ith variable pitch motor, deltatf cbiAnd the current transformer temperature deviation of the ith variable pitch motor is obtained.
6) Constructing a temperature deviation fault characteristic model of the variable pitch motor:
the temperature data of the variable pitch motors comprise temperature data t of the first to third variable pitch motorsm1-tm3;
The temperature deviation fault characteristic model of the variable pitch motor is as follows:
wherein, tm0For the temperature deviation limit, delta, of the pitch motortm1-δtm3The temperature deviation of the first variable pitch motor, the second variable pitch motor and the third variable pitch motor.
7) Constructing a variable pitch motor current fault characteristic model:
the variable pitch motor current data comprise current data I of the first to third variable pitch motorsm1-Im3;
The current fault characteristic model of the variable pitch motor is as follows:
wherein, Im0Is the current deviation limit, delta I, of the pitch motorm1-δIm3The current deviation of the first pitch motor, the second pitch motor and the third pitch motor.
8) Constructing a variable pitch motor rotating speed characteristic model:
the variable pitch motor rotating speed data comprises rotating speed data n of a first variable pitch motor, a second variable pitch motor, a third variable pitch motor and a fourth variable pitch motorm1-nm3;
The variable pitch motor rotating speed characteristic model is as follows:
wherein n is
m0Is the average rotating speed of a variable pitch motor and meets the requirement
δn
m1-δn
m3The rotating speed deviation of the first variable pitch motor, the second variable pitch motor and the third variable pitch motor.
9) Constructing a fault characteristic model of the variable-pitch bearing grease pump:
wherein,
respectively is the upper limit value and the lower limit value of the pressure at the outlet of the ith variable-pitch bearing grease pump, p
bgpiFor the ith variable pitch bearing grease pump outlet pressure data,
and
and the pressure upper limit deviation and the pressure lower limit deviation of the ith variable pitch shaft oil pump are obtained.
10) Constructing a pressure fault characteristic model of an outlet of a variable pitch gear grease pump:
wherein,
respectively is the upper limit value and the lower limit value of the pressure at the outlet of the ith variable pitch gear grease pump, p
ggpiFor the ith pitch gear grease pump outlet pressure data,
and
pressure upper limit of ith variable pitch gear grease pumpDeviation from the lower pressure limit.
And step 3: constructing a fault diagnosis model by using the fault characteristics, which comprises the following specific steps:
1) constructing a fault diagnosis model of a variable pitch power supply system:
1.1 constructing a variable pitch battery fault diagnosis model:
if the battery pack for the ith blade has:
the relative voltage deviation of the first variable-pitch battery pack, the second variable-pitch battery pack and the third variable-pitch battery pack meets delta Vbpi≥100%*(Vs-Vd)/VsThen, it can be judged that the ith battery pack has a fault, wherein VsIs the rated voltage, V, of the battery packdThe end-of-discharge voltage of the battery pack, when the battery pack voltage is less than or equal to the end-of-discharge voltage at the time of operation, indicates that the battery pack has been damaged.
1.2, constructing a fault diagnosis model of a variable-pitch battery charger:
because the first to third become oar group battery independent work, do not have mutual influence, rare the condition that breaks down simultaneously, consequently, when the voltage relative deviation of first to third become oar group battery satisfies:
and judging that the variable pitch battery charger is in fault.
1.3, constructing a high-temperature fault diagnosis model of the converter:
because the converter has thermal overload protection, in order to prevent that the thermal overload protection system starts to influence the normal operation of aerogenerator, need in time report an emergency and ask for help or increased vigilance when the converter temperature exceeds temperature limit 10%, consequently, the converter temperature deviation when first to third become oar motor satisfies:
δtf cbiand if the current transformer of the ith variable pitch motor has a high-temperature fault, judging that the current transformer of the ith variable pitch motor has the high-temperature fault.
2) Constructing a fault diagnosis model of a mechanical component of a variable pitch system:
2.1 constructing a fault diagnosis model of the variable pitch gearbox:
the maximum current allowed by the variable pitch motor is generally 110% of the rated current, and when the current of the variable pitch motor is greater than 10% of the rated current, the temperature of the variable pitch motor exceeds the temperature limit value by 10% and reaches an alarm value, so that the characteristic can be used as a fault judgment index. Therefore, when the current deviation of the ith variable pitch motor and the temperature deviation of the ith variable pitch motor meet the following conditions:
the fault of the ith variable pitch gearbox can be judged.
If the upper limit deviation and the lower limit deviation of the ith variable pitch gear grease pump meet the following requirements at the same time:
or
It can be further judged that: failure of the ith pitch gearbox.
2.2, constructing a fault diagnosis model of the variable pitch bearing:
three become oar bearings mutually independent, each other does not influence, and the rare three condition that becomes the oar bearing and break down simultaneously, consequently, when following the formula and hold:
the current deviation of the first to the third variable pitch motors satisfies
And the temperature deviation of the first to the third variable pitch motors meets the requirement
And the upper limit deviation and the lower limit deviation of the first to third variable pitch shaft oil pumps meet the conditions:
or
And the fault of the variable pitch bearing can be judged.
3) Constructing a control system fault diagnosis model of a variable pitch system:
when the variable pitch system has faults, after the faults of the variable pitch power supply system in 1) and the mechanical parts of the variable pitch system in 2) are eliminated, if the variable pitch system still has fault points, the faults are considered as the faults of the control system of the variable pitch system. The specific diagnosis method comprises the following steps:
3.1 constructing a variable pitch angle difference fault diagnosis model:
the pitch angle deviation delta β of the existing wind generating set is knownbiThe upper limit value of the pitch angle deviation is 2 degrees, the allowable deviation of the pitch angle is set to be a percent, the upper limit value of the pitch angle deviation is limited to be 2a percent, and when the relative deviation of the pitch angle and the deviation delta β of the pitch angle are achievedbiSatisfies the following formula:
Judging that the B encoder of the ith blade has a fault;
when the relative deviation of the pitch angle and the deviation of the pitch angle delta βbiSatisfies the following formula:
and is
The failure of the encoder A of the ith blade is judged.
Preferably, a has a value of 5.
3.2, constructing a blade limit switch trigger early fault diagnosis model:
in the existing wind power generation system, the setting value of the limiter of the blade angle is generally 91 degrees, if the relative deviation of the pitch angle and the blade angle satisfy the following formula:
namely, the encoder works normally, the paddle does not reach the normal action value of the paddle limit switch at the moment, the fault alarm occurs at the moment, and the diagnosis fault reason is that the trigger of the paddle limit switch is earlier.
3.3 constructing a high-temperature fault diagnosis model of the variable pitch motor:
if: variable pitch motor temperature deviation deltatmiThe temperature of the variable pitch motor is more than or equal to 10.0 percent, namely the temperature of the variable pitch motor exceeds the temperature limit value by 10 percent, and the high-temperature fault of the variable pitch motor can be judged to occur in the ith blade;
if the temperature deviation of the variable pitch motor and the current deviation of the variable pitch motor meet the following conditions:
the high-temperature fault of the variable pitch motor of the ith blade can be judged, and the fault is mostly caused by the fault of the variable pitch gearbox.
3.4, constructing a high-rotating-speed fault diagnosis model of the variable pitch motor:
generally, the allowable rotation speed deviation of the existing wind power generator is the same as the a%, and the rotation speed of the pitch motor is limited not to exceed 31(deg/s), if the following two formulas are satisfied:
the rotating speed deviation of the variable pitch motor meets
And the rotating speed of the variable pitch motor meets
The fault that the rotating speed of the variable pitch motor is too high can be judged, and the fault is mostly caused by the fault of the A encoder.
3.5 constructing a variable pitch failure diagnosis model:
when the encoder works well and the blade deviation exceeds a limit value, the variable-pitch failure condition is determined, namely the following formula is satisfied:
the relative deviation of the pitch angle measured by the A encoder satisfies
And the relative deviation of the pitch angle measured by the B encoder satisfies
And the theoretical deviation of the pitch angles of the first to third blades satisfies
It can be judged that a pitch failure fault has occurred.
3.6 constructing a pitch system signal transmission fault diagnosis model:
the following equation holds:
the relative deviation of the rotating speed of the low-speed shaft meets delta nlsNot less than 10.0 percent and the relative fluctuation of the rotating speed of the wind wheel meets delta nmsAnd if the pitch control signal transmission fault is more than or equal to 10.0 percent, the occurrence of the pitch control signal transmission fault can be judged.
And 4, step 4: and acquiring real-time fault alarm data of an SCADA system of the wind driven generator, inputting the real-time fault alarm data into a fault characteristic model, and calculating to acquire real-time fault characteristics.
And 5: and (4) inputting the real-time fault characteristics obtained in the step (4) into the fault diagnosis model to obtain a fault diagnosis result, wherein the fault diagnosis result comprises a fault reason and a fault position.
In this embodiment, the data collector is used to obtain the operating data of the various wind power generators measured by the SCADA system, and the computer is used to store and complete data storage, fault diagnosis and result display.
Compared with the prior art, the fault diagnosis method for the variable pitch system of the wind driven generator acquires the required fan operation data from the existing SCADA system, extracts the fault characteristics of fault high-occurrence positions in the power system of the variable pitch system, the mechanical components of the variable pitch system and the control system of the variable pitch system, constructs a comprehensive fault characteristic model, can diagnose the real-time fault position of the wind driven generator set to the fault reason, and improves the overhaul efficiency.
The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention.