Method and system for detecting abrasion loss of brake of offshore wind generating set
Technical Field
The invention relates to the field of wind power generation, in particular to a method and a system for detecting the abrasion loss of a brake of an offshore wind generating set.
Background
Wind power generation is the most potential renewable energy power generation technology except for hydroelectric power generation, and in recent years, wind power generation has been rapidly developed in China, and land power generation has become popular. In order to further utilize wind resources, offshore wind power generation is starting and developing vigorously, and due to the fact that offshore wind speed is high and is not affected by obstacles and surface roughness, wind speed and wind direction are stable, turbulence is low, and offshore wind power development value is high.
When a fan is overhauled and maintained or in a strong wind state, shutdown is realized through a brake, the brake performance of the fan is inevitably influenced by continuous abrasion of the brake in the long-term use process, so that the safe operation of the fan is endangered, and particularly in an offshore wind generating set, the importance of online monitoring and service life prediction of the brake of the wind driven generator is more and more prominent.
In the prior art, an offshore wind generating set does not have a brake wear amount detection device, the brake wear amount is difficult to automatically measure, the brake wear amount can only be manually and periodically checked and maintained, the brake wear amount is immediately replaced once damage is found, real-time monitoring cannot be achieved, and a runaway phenomenon is possible to happen once the brake fails, so that danger is brought, and great loss is also caused.
Disclosure of Invention
The invention aims to overcome the defects in the prior art and provide a method and a system for detecting the brake wear of an offshore wind turbine generator system.
The purpose of the invention can be realized by the following technical scheme:
a method for detecting abrasion loss of a brake of an offshore wind generating set comprises the following steps:
s1: acquiring historical data, wherein the historical data comprises operation data of a brake and the abrasion loss of the brake;
s2: extracting n (n >0) pieces of feature data from the operating data, and preprocessing the feature data to obtain a sample data set consisting of the feature data and the abrasion loss;
s3: constructing a three-layer BP neural network, which comprises an input layer, a hidden layer and an output layer, wherein the number of neurons in the input layer is n, the number of neurons in the hidden layer is 2n +1, and the number of neurons in the output layer is 1;
s4: training the BP neural network based on the sample data set, and updating the weight of the BP neural network according to the following formula in the training process:
wherein, Δ wkjRepresenting input and hidden layersThe connection weight of (1); Δ vikRepresenting the connection weight of the hidden layer and the output layer; q represents the number of iterations in the training process; alpha and beta represent learning rate, gamma represents momentum factor, the value is (0, 1), when weight is updated, the ratio of weight and error in current iteration can be flexibly adjusted through gamma, and E represents error between expected output and actual output of output neuron;
s5: repeating the step S4 until the iteration number is equal to the preset iteration number threshold or the prediction error of the BP neural network is smaller than the preset training error threshold, so as to obtain a wear loss prediction model;
s6: the method comprises the steps of obtaining operation data of a brake of the offshore wind generating set, extracting characteristic data from the operation data, preprocessing the characteristic data, inputting a wear loss prediction model, and obtaining a wear loss prediction value of the brake.
Further, step S7 is also included, which specifically includes: after the preset time period, step S6 is executed, and the actual wear amount of the brake is obtained at the same time, and if the error between the actual wear amount and the predicted wear amount is greater than the preset model error threshold, step S1 is repeated.
Further, in the steps S2 and S6, before extracting the feature data from the operation data, data cleaning is further included, specifically: and denoising the operating data, and clearing abnormal data in the operating data, wherein the abnormal data is the operating data with a vacant field or the operating data with a field value not in a field specified interval.
Further, in the steps S2 and S6, the preprocessing the feature data includes data normalization, where the normalization formula is:
wherein x represents a characteristic data value, max represents a maximum value of the characteristic data, min represents a minimum value of the characteristic data, x represents a maximum value of the characteristic data, andnewrepresenting the normalized feature data value.
Further, in step S5, the training error threshold value is 1%.
Further, after obtaining the predicted wear amount of the brake in step S6, the method further includes: and obtaining the service life predicted value of the brake according to the model of the brake and the wear loss predicted value.
A detection system for the abrasion loss of a brake of an offshore wind generating set is based on the detection method for the abrasion loss of the brake of the offshore wind generating set, and comprises the following steps:
the data acquisition device is used for acquiring the operation data of the brake;
the data analysis platform outputs a predicted value of the abrasion loss of the brake based on the abrasion loss prediction model and the operation data of the brake;
the wireless communication device is respectively in communication connection with the data acquisition device and the data analysis platform and is used for transmitting the operation data of the brake to the data analysis platform;
and the storage device is connected with the data analysis platform and is used for storing the running data and the predicted value of the wear loss of the brake.
Further, the data acquisition device comprises an AD conversion circuit and a signal amplification circuit.
Further, the wireless communication device performs data transmission through a GPRS network.
Furthermore, the detection system also comprises a local storage device and a display system, wherein the local storage device is electrically connected with the data acquisition device and is used for storing the operation data of the brake; and the display system is connected with the data analysis platform and is used for displaying the predicted value of the abrasion loss of the brake.
Compared with the prior art, the invention has the following beneficial effects:
(1) by acquiring the operation data of the brake, and predicting the abrasion loss of the brake through the BP neural network, the abrasion condition of the brake of the offshore wind driven generator can be known in daily operation, active maintenance is carried out before the brake breaks down, and the operation reliability of the whole machine is improved.
(2) Compared with the traditional training algorithm, the weight updating formula in the BP neural network training process is improved, the weight and the ratio of errors in the current iteration can be flexibly adjusted when the weight is updated, and the algorithm performance is higher.
(3) The running data of the brake is transmitted to the data analysis platform through the wireless communication device, the abrasion loss is predicted on the data analysis platform, and the local storage device is further arranged, so that the safety of data storage is guaranteed when wireless communication fails.
Drawings
FIG. 1 is a flow chart of a method for detecting abrasion loss of a brake of an offshore wind turbine generator system.
Detailed Description
The invention is described in detail below with reference to the figures and specific embodiments. The present embodiment is implemented on the premise of the technical solution of the present invention, and a detailed implementation manner and a specific operation process are given, but the scope of the present invention is not limited to the following embodiments.
Example 1:
a method for detecting the abrasion loss of a brake of an offshore wind generating set is shown in figure 1 and comprises the following steps:
s1: acquiring historical data, wherein the historical data comprises operation data of a brake and the abrasion loss of the brake;
s2: extracting n (n >0) pieces of feature data from the operating data, and preprocessing the feature data to obtain a sample data set consisting of the feature data and the abrasion loss;
s3: constructing a three-layer BP neural network, which comprises an input layer, a hidden layer and an output layer, wherein the number of neurons in the input layer is n, the number of neurons in the hidden layer is 2n +1, and the number of neurons in the output layer is 1;
s4: training the BP neural network based on the sample data set, and updating the weight of the BP neural network according to the following formula in the training process:
wherein, Δ wkjRepresenting the connection weight of the input layer and the hidden layer; Δ vikRepresenting the connection weight of the hidden layer and the output layer; q represents the number of iterations in the training process; alpha and beta represent learning rate, gamma represents momentum factor, the value is (0, 1), when weight is updated, the ratio of weight and error in current iteration can be flexibly adjusted through gamma, the performance of training algorithm is improved, and E represents error between expected output and actual output of output neuron;
s5: repeating the step S4 until the iteration number is equal to the preset iteration number threshold or the prediction error of the BP neural network is smaller than the preset training error threshold, so as to obtain a wear loss prediction model;
s6: the method comprises the steps of obtaining operation data of a brake of the offshore wind generating set, extracting characteristic data from the operation data, preprocessing the characteristic data, inputting a wear loss prediction model, and obtaining a wear loss prediction value of the brake.
S7: after the preset time period, step S6 is executed, and the actual wear amount of the brake is obtained at the same time, and if the error between the actual wear amount and the predicted wear amount is greater than the preset model error threshold, step S1 is repeated.
After a period of time, the error between the actual wear loss and the predicted wear loss value can be detected, if the error is too large, the prediction effect of the wear loss prediction model is not ideal, the latest data is obtained again, and the wear loss prediction model is retrained.
The operation data of the brake includes various information such as time, operation speed, braking information, voltage, current, and the like, and in steps S2 and S6, before extracting the characteristic data from the operation data, the method further includes data cleaning, specifically: and denoising the operating data, and clearing abnormal data in the operating data, wherein the abnormal data is the operating data with a vacant field or the operating data with a field value not in a field specified interval. Such as running data with missing time, running data with missing running speed, running data with a negative time value, etc.
In order to eliminate the influence of dimension between different feature data, in steps S2 and S6, the feature data are normalized by the following formula:
wherein x represents a characteristic data value, max represents a maximum value of the characteristic data, min represents a minimum value of the characteristic data, x represents a maximum value of the characteristic data, andnewrepresenting the normalized feature data value.
In this embodiment, the maximum number of iterations is 500, and the value of the training error threshold is 1%.
In step S6, after the predicted wear amount value of the brake is obtained, the predicted life value of the brake can be obtained according to the model number and the predicted wear amount value of the brake.
A detection system for brake wear loss of an offshore wind generating set comprises:
the data acquisition device is used for acquiring the operation data of the brake; the data acquisition device comprises an AD conversion circuit and a signal amplification circuit, converts received information to form a data packet, and sends the data packet through the wireless communication device.
In order to ensure the reliability of data storage, a local storage device can be arranged and is electrically connected with the data acquisition device and used for storing the operation data of the brake; once the wireless transmission fails, the data in the local storage may be used.
The data analysis platform outputs a predicted value of the abrasion loss of the brake based on the abrasion loss prediction model and the operation data of the brake; and after receiving the data, the data analysis platform processes the data and inputs the data into the wear loss prediction model to obtain the wear loss prediction value of the brake. A display system can be arranged to display the operation data of the brake, the predicted value of the abrasion loss and some working parameters of the wind generating set.
The wireless communication device (WTD) is respectively in communication connection with the data acquisition device and the data analysis platform and is used for transmitting the operation data of the brake to the data analysis platform; and data transmission is carried out through a GPRS network, and bidirectional data transmission between the data acquisition device and the data analysis platform is realized.
And the storage device is connected with the data analysis platform and is used for storing the running data and the predicted value of the wear loss of the brake. The storage device can use a cloud storage platform, and stored data can be checked and analyzed more flexibly in subsequent work.
And an alarm system can be further arranged, and when the obtained predicted value of the wear loss exceeds a preset safety threshold value, alarm information is sent out to remind a worker to maintain or replace the brake.
The foregoing detailed description of the preferred embodiments of the invention has been presented. It should be understood that numerous modifications and variations could be devised by those skilled in the art in light of the present teachings without departing from the inventive concepts. Therefore, the technical solutions available to those skilled in the art through logic analysis, reasoning and limited experiments based on the prior art according to the concept of the present invention should be within the scope of protection defined by the claims.