Non-contact monitoring system and monitoring method for blade faults of offshore wind turbine
Technical Field
The invention belongs to the field of instruments and meters, and particularly relates to a non-contact monitoring system and a non-contact monitoring method for blade faults of an offshore wind turbine based on pneumatic acoustic signal characteristics in the field.
Background
The traditional energy can not meet the sustainable development requirements of resources and environment, the final source of wind energy resources is solar energy which is inexhaustible and inexhaustible, and people pay more and more attention to and pay attention to the final source, and the offshore wind power becomes an important direction for the development of the wind power technology due to the progress and maturity of the wind power technology.
However, since the offshore wind farm is generally built in an intertidal zone or an offshore area, the construction cost is high, and the complex marine environment increases the difficulty in operating and maintaining the offshore wind turbine. The wind turbine blade is used as a wind energy acquisition device, the reliability of the wind turbine blade directly affects the power generation quality and efficiency of an offshore wind turbine generator, and in addition, the offshore wind turbine blade is larger in size and higher in manufacturing cost than an onshore wind turbine blade, and accordingly, after serious faults occur, the destructiveness is larger, and the economic loss is higher. However, the current home and abroad wind turbine blade fault detection and diagnosis methods still stay at a relatively low level. Therefore, the development of a real-time online monitoring system and a monitoring method which can timely detect the fault and accurately identify the fault type at the initial stage of the fault of the fan blade and provide support and basis for fault elimination has important value.
On one hand, the sensor used in the existing online detection mode of the fan blade fault needs to be arranged in the fan blade in advance, which can generate adverse effect on the structure of the fan blade, reduce the strength of the blade and increase the manufacturing difficulty of the blade; on the other hand, once the prefabricated sensor fails, the maintenance cost is high.
Disclosure of Invention
The invention aims to solve the technical problem of providing a non-contact monitoring system and a non-contact monitoring method for blade faults of an offshore wind turbine based on pneumatic acoustic signal characteristics.
The invention adopts the following technical scheme:
the non-contact monitoring system for the blade fault of the offshore wind turbine has the improvement that: the system comprises a meteorological information acquisition system arranged on an offshore wind turbine foundation, a tower foundation or an independent platform, a hydrological information acquisition system arranged in an offshore area near the offshore wind turbine, and a pneumatic acoustic acquisition system arranged on the offshore wind turbine foundation or the tower, wherein data acquired by the meteorological information acquisition system, the hydrological information acquisition system and the pneumatic acoustic acquisition system are transmitted to an acquisition node in real time and then transmitted to an onshore data center through a wireless terminal by the acquisition node, and the data center, the monitoring system and the monitoring equipment are connected and communicated through an industrial Ethernet.
Furthermore, the number of the offshore wind turbines is more than two, and each offshore wind turbine is provided with a meteorological information acquisition system, a hydrological information acquisition system, a pneumatic acoustic acquisition system, an acquisition node and a wireless terminal.
Furthermore, the meteorological information acquisition system comprises a temperature sensor, a humidity sensor, a wind sensor, a rainfall sensor and a lightning sensor.
Further, the hydrological information acquisition system comprises a wave sensor, an ocean current sensor and a tide sensor.
Furthermore, the pneumatic acoustic acquisition system comprises an acoustic sensor and an acoustic signal processing unit, the measurement range of the acoustic sensor is 20 Hz-20 kHz, the sampling frequency of a digital-to-analog converter of the acoustic signal processing unit is not lower than 200kHz, the acquisition bit number is not lower than 16 bits, and the acquisition channel is not less than 4 channels.
Further, the wireless terminal transmits data to an onshore data center by means of microwave communication.
Furthermore, the monitoring equipment comprises a central monitoring room computer monitoring platform, a remote computer and handheld equipment.
The non-contact monitoring method for the blade fault of the offshore wind turbine uses the monitoring system, and the improvement is that the non-contact monitoring method comprises the following steps:
(1) acquiring meteorological information through a meteorological information acquisition system, and correcting noise interference of wind noise, extreme storms, thunder and rain; acquiring hydrological information through a hydrological information acquisition system, and correcting noise interference of sea waves, currents and tides; acquiring pneumatic acoustic information of the fan blade through a pneumatic acoustic acquisition system; the acquisition process is controlled by the acquisition node and the acquired data is transmitted to the onshore data center through the wireless terminal;
(2) carrying out decision-level information fusion on meteorological information, hydrological information and aerodynamic acoustic information of the fan blade, correcting interference of environmental noise on the acquisition of the aerodynamic acoustic information, calculating multi-scale sample entropy of the aerodynamic acoustic information based on variational modal decomposition, namely extracting sample entropy of time series on different scales, so as to construct a state feature vector set of the fan blade, analyzing and extracting time-frequency features of the constructed aerodynamic acoustic information through a time-frequency analysis tool, inputting the multi-scale sample entropy feature vector set constructed by test samples into a neural network for learning and training, continuously updating network weight and structure, and finally converging to obtain a neural network model for identifying and classifying fan blade faults;
(3) downloading the neural network model into a monitoring system, calculating the time-frequency characteristics of newly acquired pneumatic acoustic information by the monitoring system, inputting the time-frequency characteristics into the neural network model for identification and classification, and updating the weight and the neural network structure in time according to the new characteristics by the neural network model to enhance the generalization capability of the neural network;
(4) the monitoring system provides the state and the fault information of each offshore wind turbine blade in real time, sends alarm information to the monitoring equipment when a fault occurs, and meanwhile, the state of each offshore wind turbine blade can be checked on the monitoring equipment in real time and is processed when the fault occurs.
Further, the pneumatic acoustic acquisition system removes the interference of the background noise of the marine environment by using a self-adaptive filtering method according to the time-frequency characteristics of the signals to obtain pure pneumatic acoustic information of the fan blade.
The invention has the beneficial effects that:
the monitoring system disclosed by the invention does not need to damage the original structure of the fan blade, and is convenient for maintaining the detection equipment. The monitoring requirement of the traditional monitoring room can be met, and meanwhile, a remote computer and handheld equipment can be convenient for field maintenance.
The monitoring method disclosed by the invention comprehensively and accurately describes the pneumatic noise signal of the fan and the environmental background noise through a multi-sensor information fusion technology, and corrects the interference of the environmental noise on the pneumatic acoustic information acquisition. An offshore wind turbine blade aerodynamic acoustic feature vector set is established through a self-adaptive signal processing method, and then state monitoring and fault identification of the offshore wind turbine blade are achieved through a machine learning method.
Drawings
FIG. 1 is a schematic diagram of the monitoring system disclosed in embodiment 1 of the present invention;
fig. 2 is a schematic flow chart of the monitoring method disclosed in embodiment 1 of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be described in further detail below with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
Embodiment 1, as shown in fig. 1, this embodiment discloses a non-contact monitoring system for blade faults of an offshore wind turbine, where the system includes a meteorological information acquisition system disposed on an offshore wind turbine foundation, a tower foundation or a separate platform, a hydrological information acquisition system disposed in an offshore area near the offshore wind turbine, and a pneumatic acoustic acquisition system disposed on the offshore wind turbine foundation or a tower, where data acquired by the meteorological information acquisition system, the hydrological information acquisition system, and the pneumatic acoustic acquisition system are transmitted to an acquisition node in real time, and then transmitted to an onshore data center, the monitoring system, and a monitoring device via an industrial ethernet connection.
In this embodiment, the number of the offshore wind turbines is two or more, and each offshore wind turbine is provided with a meteorological information acquisition system, a hydrological information acquisition system, a pneumatic acoustic acquisition system, an acquisition node and a wireless terminal, so that a shore data center can obtain data of each offshore wind turbine, and a monitoring system can read various information of each offshore wind turbine of an offshore wind farm at any time through the data center. The meteorological information acquisition system comprises a temperature sensor, a humidity sensor, a wind sensor, a rainfall sensor and a lightning sensor. The hydrological information acquisition system comprises a wave sensor, an ocean current sensor and a tide sensor. The pneumatic acoustic acquisition system comprises an acoustic sensor and an acoustic signal processing unit, the measuring range of the acoustic sensor is 20 Hz-20 kHz, the sampling frequency of a digital-to-analog converter of the acoustic signal processing unit is not lower than 200kHz, the acquisition number is not lower than 16, and in order to ensure the accuracy of acquiring acoustic signals, the acquisition channel is not less than 4 channels. The wireless terminal transmits data to an onshore data center by means of microwave communication. The monitoring equipment comprises a central monitoring room computer monitoring platform, a remote computer and handheld equipment, wherein the handheld equipment is intelligent mobile phone equipment, and various monitoring equipment can realize functions of checking fan blade state data, monitoring faults, processing alarms and the like.
As shown in fig. 2, the embodiment further discloses a non-contact monitoring method for offshore wind turbine blade fault, and the monitoring system includes the following steps:
(1) acquiring meteorological information through a meteorological information acquisition system, and correcting noise interference of wind noise, extreme storms, thunder and rain; acquiring hydrological information through a hydrological information acquisition system, and correcting noise interference of sea waves, currents and tides; acquiring aerodynamic acoustic information of the fan blade through an aerodynamic acoustic acquisition system, specifically, in the embodiment, the aerodynamic acoustic acquisition system performs variation modal decomposition on a signal, and by comparing the correlation with the rotation period of the fan blade and the time-frequency characteristics of sub-bands, the sub-bands interfered by background noise of the marine environment are removed, so that pure aerodynamic acoustic information of the fan blade is obtained; the acquisition process is controlled by the acquisition node and the acquired data is transmitted to the onshore data center through the wireless terminal;
(2) the method comprises the steps of carrying out decision-level information fusion on meteorological information, hydrological information and aerodynamic acoustic information of the fan blade, correcting interference of environmental noise on the acquisition of the aerodynamic acoustic information, measuring the complexity of signals on the whole by calculating multi-scale sample entropies of the aerodynamic acoustic information based on variation modal decomposition, namely extracting the sample entropies of time series on different scales, mining deep-level detail characteristics of the signals on different scales to construct a state characteristic vector set of the fan blade, analyzing and extracting time-frequency characteristics of the aerodynamic acoustic information by a time-frequency analysis tool when the fan blade fails, inputting the multi-scale sample entropy characteristic vector set established by a test sample into a neural network for learning and training, and continuously updating network weight and structure, finally converging to obtain a neural network model for identifying and classifying the faults of the fan blades;
(3) downloading the neural network model into a monitoring system, calculating the time-frequency characteristics of newly acquired pneumatic acoustic information by the monitoring system, inputting the time-frequency characteristics into the neural network model for identification and classification, and updating the weight and the neural network structure in time according to the new characteristics by the neural network model to enhance the generalization capability of the neural network;
(4) the monitoring system provides the state and the fault information of each offshore wind turbine blade in real time, sends alarm information to the monitoring equipment when a fault occurs, and meanwhile, the state of each offshore wind turbine blade can be checked on the monitoring equipment in real time and is processed when the fault occurs.
In this embodiment, the aeroacoustic acquisition system removes the interference of the background noise of the marine environment by using an adaptive filtering method according to the time-frequency characteristics of the signals, so as to obtain pure aeroacoustic information of the fan blade.