KR102681649B1 - Monitoring method for the support structure of a wind turbine - Google Patents

Abstract

The present invention relates to a method for monitoring the integrity of a support structure by checking changes in the support structure corresponding to conditions that vary depending on whether the wind turbine is operated, even if there is no measurement information of the wind turbine, and is installed on the support structure of the wind turbine. Calculate the natural frequency and slope of the support structure and the stress acting on the support structure from the inclinometer, accelerometer and strain meter, and compare the calculated natural frequency, slope and stress with the management standards to determine the safety of the support structure. The standard value is set separately for normal operation of the wind turbine and emergency stop, so that monitoring is carried out differently depending on the operating status of the wind turbine.

Description

{MONITORING METHOD FOR THE SUPPORT STRUCTURE OF A WIND TURBINE}

The present invention relates to a method for monitoring the integrity of the structural safety of the support structure of a wind turbine. More specifically, the change in the support structure corresponding to the state that varies depending on whether the wind turbine is in operation even without measurement information of the wind turbine. It relates to a method of monitoring the integrity of the support structure by checking.

As fossil power generation, which accounts for a significant portion of carbon dioxide emissions worldwide, needs to be converted to power generation using new and renewable energy such as wind power, the size of the wind power generation market is expected to continue to expand.

A wind turbine is a device that converts wind energy into kinetic energy through a wind turbine and then converts it back into electrical energy. It consists of a wind turbine consisting of blades, a gearbox, a generator, a nacelle, etc., and a tower structure that supports it. .

Power generation by a wind generator is determined by the strength of the wind, so the wind turbine is located at a very high place so that it can receive greater wind pressure. Accordingly, the support structure also has a long pole structure and has a structural support for it. It becomes difficult for workers to access stability.

Accordingly, various methods have been proposed to remotely manage the support structures of wind power generators, and as one example, Registered Patent Publication No. 10-1507008 has proposed a remote safety evaluation system for offshore wind power generation structures.

The remote safety evaluation system includes an acceleration sensor installed in each of a plurality of offshore wind power generation structures consisting of substructures, towers, and nacelles to measure acceleration corresponding to vibration of each of the offshore wind power generation structures; A field terminal that collects field data from the plurality of offshore wind power structures and transmits it remotely by wire or wirelessly along with the acceleration signal measured by the acceleration sensor; And converting the acceleration signal transmitted from the field terminal into a displacement and comparing it with a preset reference displacement, primarily determining whether the offshore wind power generation structure is abnormal according to the displacement comparison result, and each of the offshore wind power generation structures. It is configured to include a remote terminal that remotely evaluates the safety of the offshore wind power generation structure by comparing the primary judgment data to secondarily determine whether each of the offshore wind power generation structures is abnormal.

Meanwhile, the stress generated in the support structure that supports the wind turbine may vary depending on whether the wind turbine is in operation or the operating state of the blades corresponding to wind pressure. For example, if the wind speed exceeds the rated wind speed, the wind power generator stops operating. However, in this case, the wind turbine does not yaw according to the wind direction and the blades do not fold, so the external load acting on the wind power generator and support structure is the greatest. However, on the other hand, since the action of such a large load is temporary, the application standards must be different from those in driving conditions.

However, the above-described prior technologies determine the status of the support structure based only on values obtained through uniform sensor measurements without considering whether the wind turbine is in operation, wind speed, and the operating condition of the wind turbine according to its changes, so diagnosis is not possible. The reliability of the results is not high.

In addition, monitoring of the operating status of wind turbines is managed by the manufacturer and is not disclosed, making it difficult to obtain information on their operating status.

KR 10-1529701 B1

The present invention is intended to solve the above-mentioned problems of the prior art. It is possible to easily and continuously monitor the integrity of the structure supporting the wind power generator without direct operation information about the wind power generator, and has a high level of accuracy in the monitoring results. The purpose of this study is to provide a method for monitoring the structural integrity of wind turbine support structures that can ensure reliability.

In the most preferred embodiment of the present invention to solve the above problems, the natural frequency and inclination of the support structure and the stress acting on the support structure are calculated from the inclinometer, accelerometer, and strain meter installed on the support structure of the wind power generator, and the calculated unique The safety of the support structure is determined by comparing the frequency, slope, and stress with the management standards, and the above management standards are set separately for normal operation and emergency stop of the wind turbine, so that monitoring is performed according to the operation status of the wind turbine. Let it be done differently.

In one embodiment of the present invention regarding the installation of sensors for calculating or confirming the natural frequency of a support structure, an inclinometer is installed at the top of the support structure, an accelerometer is installed at the center of the support structure, and a strain gauge is installed at the bottom of the support structure.

One embodiment of the present invention regarding the calculation of the natural frequency is made using data measured from an inclinometer, an accelerometer, and a strain gauge in the front, rear, and left and right directions of the support structure, and a management standard for comparing the natural frequency calculated thereby. The reference natural frequency is set through computerized values in virtual space.

One embodiment of the present invention regarding the confirmation of the slope is carried out in the forward and backward and left and right directions by measuring the inclinometer installed on the support structure, and is a standard of the normal range among the management standards at the time of emergency stop to prepare for the slope confirmed by this. The slope is set to a structurally analyzed value by applying the maximum horizontal force allowed to the support structure to the wind turbine location in virtual space.

In another embodiment of the present invention regarding the confirmation of the slope, the normal standard slope of the management standard during normal operation is set based on the wind speed assumed to act on the wind turbine or the amount of power assumed to be produced by the wind generator.

One embodiment of the present invention regarding the calculation of the stress is performed by measuring a strain gauge installed on the support structure, and the stress in the normal range among the management standards for emergency stops to prepare for the stress calculated by this is determined by the material of the support structure. It is set based on the yield strength calculated by weight and thickness. At this time, the stress calculated by the measurement of the strain gauge can be verified at least once by the estimated wind speed at the location of the wind turbine. In addition, the estimated wind speed is the measured wind speed confirmed at a height of 2 to 5 m above the ground of the support structure. It can be calculated using the wind speed at a height of 10m above the ground provided by the Korea Meteorological Administration.

Another embodiment of the present invention regarding the calculation of the stress is made by measuring a strain gauge installed on the support structure, and the normal range of the management standard during normal operation to prepare for the stress calculated by this is the fatigue failure variable. It is set based on the value calculated by included and applied structural calculation. At this time, the stress calculated by the measurement of the strain meter can be verified by the amount of power produced by the wind power generator at least once, and the amount of power produced for verification of the stress is measured by installing a power meter on the power line. It can be done indirectly.

The present invention overlaps to confirm the natural frequency of the support structure using each of the inclinometer, accelerometer, and strain gauge, and also allows for easy verification of the stress measured by the strain gauge using the estimated wind speed and power generation amount. This ensures high reliability of the monitoring results.

In addition, the present invention enables precise monitoring by varying the management standards according to the emergency stop of the wind power generator and the normal operation.

In addition, the present invention allows monitoring of the stability of the support structure by indirectly acquiring it from the outside even without knowing the internal data about the wind turbine for monitoring, so it can be applied to the support structure of all wind turbines. It has versatility.

1 is a conceptual diagram of the monitoring method of the present invention.
Figure 2 is a table of computer modeling and eigenvalue analysis results for calculating the reference natural frequency in a test example of the present invention.
Figure 3 is a table of the results of calculating the maximum load and maximum stress through computer analysis according to wind speed of the present invention.
Figure 4 is a graph comparing the estimated wind power of the present invention and the actual wind power.
Figure 5 is a comparison table of the reference stress calculated by computer analysis based on the above estimated wind power and the measured stress.
Figure 6 is a graph comparing the power produced by the wind turbine and the stress measured by the strain gauge of the present invention.
Figure 7 is a graph comparing the power produced by a wind power generator and the power indirectly measured according to the present invention.
Figure 8 is an algorithm for determining integrity according to an embodiment of the present invention.

Hereinafter, the present invention will be described in detail with reference to the attached drawings based on the most preferred embodiment. However, when explaining the present invention in detail, if the technical idea of the present invention is obscured or unclear, the description of the known configuration will be omitted.

Figure 1 conceptually illustrates a method for monitoring the structural integrity of a support structure of a wind turbine according to the present invention.

The present invention attaches a plurality of sensors for measuring behavior to a specific position of a support structure supporting a wind power generator, collects and analyzes data on the behavior of the support structure from each of these sensors, and confirms or calculates the safety by these. By comparing each related indicator with each preset management standard, the safety status of the support structure can be monitored at all times.

In particular, the present invention analyzes the data obtained regarding a plurality of safety indicators in an overlapping manner to ensure the reliability of the monitoring results, verifies and confirms the results confirmed or calculated by these data, and also enables the wind power generator's One of the important technical features is to enable precise monitoring by setting different management standards according to operating conditions. In relation to this, it is located in Woljeong-ri, Gujwa-eup, Jeju-si, Jeju Special Self-Governing City. The capacity of the wind power generator is 3MW (top turbine; WinDS3000 ^TM , weight 192t), and the support structure is connected to a concrete direct foundation through a strong joint structure, and has a yield strength considering the thickness. It is made of S355 steel with a force of 355 MPa, has a weight of 200 tons, and has a height of 80 m. This is described in detail as an example (hereinafter referred to as a 'test example') as follows.

1) Setting management standards

The present invention calculates the natural frequency, slope, and stress values of the support structure in its current state, and compares the safety-related indicators calculated through each of these measured values with the management standards to determine the integrity of the support structure. do.

<Management standards for natural frequency>

The reference natural frequency to prepare for the natural frequency in the current state, that is, the first natural frequency in the intact state (this is referred to as the reference natural frequency), is determined by building a model of the wind power generator support structure on which the monitoring system will be installed in the virtual space of the computer. It can be confirmed by performing a computerized analysis based on this.

The results of confirming the standard natural frequency for the test example are shown in Table 1 below, as shown in FIG. 2.

No. Frequency
(rad/sec) Frequency
(cycle/sec) Period
(sec) Remark One 2.127 0.338 2.954 1st mode (Side-side) 2 2.132 0.339 2.948 1st mode (Fore-aft) 3 17.273 2.749 0.364 2nd mode (Fore-aft) 4 18.088 2.879 0.347 2nd mode (Side-side)

For the computerized analysis of the test example, the support structure was modeled using frame elements, the flange connection was considered as a load, and the RNA (Roter Nacelle Assembly) was considered eccentric by referring to the specifications of the same output.

As a result of the above computerized analysis, in the test example, the basic natural frequency is calculated to be 0.338Hz, and based on this, the change in natural frequency of the current state of the support structure is monitored.

Therefore, the management standard value of natural frequency according to the above test example can be set as shown in Table 2 below.

Adequate Within ±8% (0.311~0.365) of the reference value (0.338) caution Exceeds ±8% (0.311~0.365) to within ±12% (0.297~0.379) of the standard value serious Exceeds ±12% (0.297~0.379) of reference value

<Slope management standard>

It is assumed that the support structure is precisely constructed vertically in all directions.

However, in response to the horizontal load of wind pressure, the support structure has a cantilever structure where the lower part is a fixed end strongly connected to the foundation and the upper part is a free end, so this needs to be taken into consideration.

In addition, it is necessary to set different management standards for when the wind power generator is operating normally and when it is emergency stopped due to strong winds. For example, when a wind power generator is brought to an emergency stop due to strong winds exceeding the rated wind speed (in the test example, it was 25 m/s), the blades may be subjected to high wind pressure without being folded, but this is temporary, so the support structure While a standard slope in the normal range for determining stability can be set based on the maximum allowable stress according to the material, continuous vibration caused by the wind power generator has occurred during the period the support structure has been used during normal operation. As a result, it is necessary to consider the fatigue failure of the support structure and the current vibration during operation to set a standard slope in the normal range.

Therefore, the management standard for slope during an emergency stop of a wind turbine is set as a structurally analyzed value by applying the maximum horizontal force allowed to the support structure built in the above-mentioned virtual space to the position of the wind turbine, and as a result, Table 3 below and can be set together.

Top center bottom Adequate Within 1.13° Within 0.64° Within 0.09° caution Above 1.13° ~ Within 1.53° Greater than 0.64° to within 0.87° Greater than 0.09° to within 1.13° serious Greater than 1.53° Greater than 0.87° Greater than 0.13°

However, when a wind power generator is in normal operation (including when the blades are folded to prevent excessive power production), more stringent management standards must be set in consideration of fatigue failure of the support structure, etc., as described above, and in addition, the It must be set differently depending on the wind speed.

Additionally, since the amount of power generation varies depending on wind speed, the amount of power generation can be converted to the wind speed acting on the support structure. Therefore, the normal range of management standards when a wind turbine is normally operated can be set based on the wind speed assumed to act on the wind turbine or the amount of power assumed to be produced by the wind turbine, for example, Table 4 below can be set together.

wind speed
(m/s) Print
(W) Management standard (degree) Top center bottom caution serious caution serious caution serious 3 0 0.25 0.34 0.14 0.19 0.01 0.02 5 1,000 0.39 0.53 0.22 0.30 0.03 0.04 7 1,500 0.63 0.85 0.36 0.49 0.05 0.07 9 2,000 0.63 0.85 0.36 0.49 0.05 0.07 11 2,500 0.73 0.98 0.41 0.56 0.05 0.08 13 3,000 0.77 1.04 0.43 0.59 0.06 0.08 15 3,000 0.77 1.04 0.43 0.59 0.06 0.08 17 3,000 0.79 1.07 0.45 0.61 0.06 0.09 19 3,000 0.79 1.09 0.45 0.61 0.06 0.09 21 3,000 0.73 1.06 0.41 0.60 0.06 0.09 23 3,000 0.73 0.99 0.41 0.56 0.05 0.08 25 3,000 0.73 0.99 0.41 0.56 0.05 0.08

<Stress management standard>

As mentioned above, the stress generated by strong winds exceeding the rated wind speed is temporary, and among the management standards for determining the stability of the stress generated during an emergency stop, the stress in the normal range is determined by the material of the support structure and It is set based on the yield strength calculated by thickness.

Therefore, in the test example, the support structure is made of S355 steel with a yield strength of 355 MPa, and the stress management standard considering the thickness and safety factor can be set as shown in Table 5 below.

Adequate Within 180MPa caution Exceeding 180MPa ~ Within 255MPa serious Exceeding 255MPa

However, like the standard slope, the allowable stress when the wind power generator is operated normally is based on the value calculated by the applied structural calculation, including fatigue failure due to the use of the support structure and vibration due to the current blade in operation as variables. It should be set to .

Figure 3 shows the results of computer analysis considering the intensity (%) of turbulence (Ti) for the maximum load and maximum stress according to wind speed acting on the support structure. According to this, it can be seen that when the wind speed is 11 m/s to 19 m/s, the maximum load and maximum stress appear the largest due to the influence of turbulence.

Additionally, as will be described later, the stress acting on the support structure and the amount of power produced by the wind generator appear similar.

Therefore, it is desirable to set management standards for determining the safety of stress occurring in support structures based on wind speed or electric power so that they can be compared and reviewed efficiently. Table 6 is an example of management standards set based on wind speed or power amount.

wind speed
(m/s) Print
(W) Management standard (MPa) caution serious 3 0 30 40 5 1,000 50 70 7 1,500 90 120 9 2,000 90 130 11 2,500 100 140 13 3,000 110 150 15 3,000 110 150 17 3,000 120 160 19 3,000 120 170 21 3,000 100 150 23 3,000 100 140 25 3,000 100 140

2) Collection and analysis of data on the behavior of support structures

The present invention installs sensors such as inclinometers, accelerometers, and strain gauges in a support structure, calculates the natural frequency and inclination in the current state of the support structure from these, and the maximum stress acting on the support structure, and then calculates the maximum stress acting on the support structure. Determine the integrity of the support structure against the management standards.

At this time, sensors such as inclinometers, accelerometers, and strain gauges must be newly installed in the existing support structure, which is a circular cross-section steel structure that has already been built, and physical damage occurs when the support structure is added to the fixing means such as welding or bolting. It is desirable to attach a magnet to the housing of the sensor so that it can be easily attached and detached and fixed by its magnetic force. In this way, if the sensor is fixed to the support structure using a magnet, not only is its installation and disassembly very easy, but there is no need for separate repainting after disassembly.

In addition, it is desirable to minimize power interference from wind power generators and minimize the amount of work for installation by having measurement data from sensors, etc. transmitted to an external server using IoT wireless equipment.

<Check natural frequency>

Confirmation of the natural frequency is made individually by each data measured from the inclinometer, accelerometer, and strain meter in the front, rear, and left and right directions of the support structure. This is explained in detail as follows.

The natural frequency value of the support structure is independently confirmed using data acquired from the inclinometer, accelerometer, and strain meter installed on the support structure of the wind turbine. That is, the natural frequency of the support structure is individually calculated through FFT (Fast Fourier Transform) analysis of the change in the slope of the support structure by the inclinometer, the change in vibration acceleration of the support structure by the accelerometer, and the change in stress by the strain gauge.

The natural frequencies of each sensor are generally confirmed to be almost the same, but if there is a difference, the average value or the most unfavorable value among them is determined as the natural frequency of the support structure and compared with the management standard to ensure high reliability in determining integrity. make it possible

In addition, the inclinometer, accelerometer, and strain sensor for determining the natural frequency are installed so that the measured values are obtained with minimal interference from vibrations that occur during wind turbine operation, and the behavior of the support structure can be largely confirmed. It can be installed in different locations.

For example, the slope is greatest at the top of the support structure, so by installing an inclinometer there, the behavior can be acquired and analyzed accurately.

However, the upper part of the support structure experiences a large amount of vibration caused by the wind power generator, which interferes with the acceleration behavior of the support structure and causes the natural frequency of the support structure to be buried in the vibration of the wind power generator. Therefore, it is desirable to install the accelerometer in the central part of the support structure, where there is less interference from vibration caused by the wind turbine and where the secondary vibration mode of the support structure occurs.

In addition, the greatest stress occurs at the bottom of the support structure. Therefore, if the strain gauge is installed at the bottom of the support structure, the behavior of the support structure can be confirmed and analyzed accurately.

In this way, by installing an inclinometer at the top of the support structure, an accelerometer at the center, and a strain gauge at the bottom, it is possible to check the precise natural frequency without errors due to external interference. Each of the above sensors is also used as a means for checking inclination and calculating stress, which will be described later.

<Check the slope>

Confirmation of the current state of inclination of the support structure is made in the front-to-back and left-right directions by measuring the inclinometer installed on the support structure.

When installing an inclinometer to check the inclination, it is desirable to check the overall behavior of the support structure by installing it at the top, center, and bottom of the support structure.

<Calculation of maximum stress>

The maximum stress acting on the support structure is measured by a strain gauge installed on the support structure. For this purpose, the strain gauges are arranged to be symmetrical front-to-back and left-to-right on the same cross-section of the support structure. To calculate the maximum stress, the strain gauges arranged as above can be installed at the top, center, and bottom of the support structure.

Calculation of the maximum stress in the support structure using a strain gauge is determined by the following sequence and formula.

First, the strain with the largest absolute value ( ), and the strain with the next largest value and the same direction (same sign) ( ) to the elastic modulus ( ) to obtain the stress at each point above (the position of each strain gauge) ( , ) is calculated.

,

Maximum stress within the cross section ( )silver The position of the strain gauge with It is located between the strain gauges having, The position of the strain gauge and the maximum stress in the cross section ( The angle between positions with ) ( ) is calculated as follows.

가 된다.Therefore, the maximum stress ( )= ×

It becomes.

3) Verification

Table 7 below shows the maximum daily stress (B) calculated by the method described above after measuring the strain using a strain gauge for the support structure and the wind speed actually acting on the support structure, which was calculated by computer analysis. This is the result of comparing the maximum daily standard stress (A).

item 1st round 2nd round Maximum daily reference stress (A) 71.147 MPa 71.797 MPa Maximum daily stress (B) 68.529 MPa 70.865 MPa Allowable stress of material (C) 355 MPa 355 MPa Error rate (A-B)/C) 0.74% 0.26%

According to Table 7 above, the stress of the support structure calculated by the measurement using a strain gauge and the above-mentioned formula based on this can be judged to be sufficiently reliable.

On the other hand, the wind turbine is located high above the support structure (usually at a height of about 80 m as in the test example), and the wind speed is measured directly at this location to verify the stress determined by the measurement of the strain gauge. It's not easy to do.

Therefore, in the present invention, the maximum and minimum wind speeds are calculated by linking the measured wind speed measured at a height of 2 to 5 m above the ground with the wind speed provided by the Korea Meteorological Administration at a height of 10 m in the wind turbine installation area, and then the average value of these is calculated. Estimate the wind speed (estimated wind speed) at the wind turbine location, calculate the load acting on the support structure for each wind speed and turbulence intensity through integrated load analysis (Aero-Hydro-Servo-Elastic coupling), or build a digital twin model. By learning this, the load acting on the support structure is calculated and verified according to wind speed.

Maximum wind speed (m/s) = Min(25, Min (measured wind speed × 1.5), provided wind speed × 2.0)

Minimum wind speed (m/s) = Min(25, Max (measured wind speed × 0.5), provided wind speed × 1.0)

Estimated wind speed at wind turbine location = average value of maximum and minimum wind speeds

As a result of applying the calculation of the above estimated wind speed to a test example and checking the actual wind speed (SCADA wind speed in the orange graph) with an anemometer installed inside the wind power generator, as shown in Figure 4, the wind speed at 80m above the ground is It was confirmed to be higher than the provided wind speed at 10m (provided by the Korea Meteorological Administration, AWS wind speed in the blue graph) and similar to or somewhat lower than the estimated wind speed (estimated wind speed at the top of the tower in the green graph). Therefore, the estimated wind speed based on the above calculation can be assumed to be the actual wind speed and used.

Figure 5 compares the reference stress calculated by computer analysis based on the above-described estimated wind speed and the stress generated by measurement by a strain gauge.

For reference, the 'test target product data' in Figure 5 refers to the 'measured wind speed' measured at a position of 2 to 5 m above the ground in the support structure of the test example, and the 'Korea Meteorological Administration data' refers to the 'provided wind speed' at a height of 10 m above the ground provided by the Korea Meteorological Administration. ', and 'estimated wind speed at the top of the tower' means 'estimated wind speed' calculated as the wind speed at the wind turbine location using the above-mentioned formula. In addition, 'reference stress' refers to the stress calculated by computerized analysis of the above estimated wind speed, and 'stress generated by the test product' refers to the stress calculated by measurement of a strain gauge.

Comparing the respective stress values in FIG. 5, they generally show similar values without large deviations, and it can be seen that the wind speed at the wind turbine location can be estimated and utilized by the above-described method.

This method of estimating wind speed allows stress verification to be carried out very efficiently and easily. The stress calculated by measuring the strain gauge can be verified by the estimated wind speed at the location of the wind turbine at least once. It is desirable.

In addition, the rotation of the blades and the resulting vibrations caused by the operation of the wind turbine affect the stress acting on the support structure. Therefore, it is necessary to confirm whether the influence of wind turbine operation is reflected in the stress determined by strain gauge measurement.

Figure 6 compares the change in the amount of power produced by the wind power generator and the change in stress determined by measurement of the strain gauge.

According to this, the output of power produced in real time has a similar shape to the stress determined by measuring in real time, and it can be seen that the stress determined by measurement of the strain gauge appropriately reflects the influence of wind power generator operation depending on wind speed. there is. Therefore, it is desirable to verify the amount of power produced by the wind power generator by measuring the stress determined by measuring the strain gauge at least once.

Meanwhile, a number of sensors are installed inside the wind power generator to measure wind speed, power generation output, and movement of the generator acting on the wind power generator. As mentioned above, this information is managed by the manufacturer of the wind power generator, but is not disclosed. It is common not to.

However, as described above, it is desirable to set management standards during operation based on the amount of power produced by the wind power generator in real time and the wind speed acting on it. In the present invention, a power meter is installed on the power line to measure the power produced by the wind power generator. By indirectly measuring the amount of power in real time and using it, it is easy to set management standards and verify stress or monitor integrity.

Figure 7 shows a real-time comparison between the actual power produced by the wind turbine and the amount of power measured by a power meter installed on the power line. According to this, the results measured by the power meter and the actual amount of power produced are very similar, so the estimation of the wind power generator output by the power meter is judged to be reliable.

4) Determination of integrity

To determine the integrity of the support structure, the natural frequency and slope of the support structure and the stress acting on the support structure are calculated from the inclinometer, accelerometer and strain meter installed on the support structure of the wind power generator, and the calculated natural frequency, slope and stress are used to determine the integrity of the support structure. This is done by comprehensively confirming the safety of the support structure by comparing it with the management standards.

Of course, the above-mentioned preparation must be made based on each management standard set separately for normal operation and emergency stop of the wind power generator, as described above.

For example, in the event of an emergency stop of a wind power generator, comprehensive integrity can be determined through the algorithm illustrated in FIG. 8. Of course, during normal operation, the management standards for slope and stress should be replaced with those in Tables 4 and 6, respectively.

In the example of FIG. 8, when a caution level occurs three or more times in a row for three or more of the same measurement items, or a serious level occurs three times in a row for one or more of the same measurement items, these are judged to be a comprehensive serious level.

However, these safety evaluation standards can be set more strictly or more relaxed in consideration of the degree of deterioration of the support structure and the climate or environmental conditions of the area, and this also applies during normal operation of the wind turbine.

In the above, the present invention has been described in detail with reference to specific embodiments, but the embodiments are merely examples to make the present invention easier to understand, so those skilled in the art will understand the scope of the technical idea of the present invention. It is obvious that this can be implemented with various modifications. Accordingly, such modifications will be said to fall within the scope of the present invention as set forth in the claims.

Claims (12)

Confirm or calculate the natural frequency and slope of the support structure and the stress acting on the support structure from the inclinometer, accelerometer and strain meter installed on the support structure of the wind power generator, and compare the confirmed or calculated natural frequency, slope and stress with the management standards. Determine the safety of the support structure,
A method of monitoring the structural integrity of the support structure of a wind turbine, characterized in that the above management standards are set separately during normal operation and emergency stop of the wind turbine. According to paragraph 1,
The inclinometer is installed at the top of the support structure,
The accelerometer is installed in the center of the support structure,
A method for monitoring the structural integrity of a support structure of a wind turbine, characterized in that the strain gauge is installed at the lower part of the support structure. According to paragraph 1,
A method for monitoring the structural integrity of a support structure of a wind turbine, characterized in that the inclinometer, accelerometer, and strain gauge are each installed on the support structure via a magnet. According to paragraph 1,
Confirmation of the natural frequency is made by measuring data from inclinometers, accelerometers, and strain meters in the front, rear, and left and right directions of the support structure,
A method for monitoring the structural integrity of the support structure of a wind power generator, characterized in that the standard natural frequency of the management standard to prepare for the natural frequency confirmed by this is set through a computerized value in virtual space. According to paragraph 1,
The inclination is confirmed in the front, rear, and left directions of the support structure by measuring the inclinometer installed on the support structure,
The standard slope in the normal range among the emergency stop management standards to prepare for the slope confirmed by this is set to a structurally analyzed value by loading the maximum horizontal force allowed for the support structure in virtual space at the wind turbine location. Methods for monitoring the structural integrity of a generator's support structures. According to paragraph 1,
The inclination is confirmed in the front, rear, and left directions of the support structure by measuring the inclinometer installed on the support structure,
The normal standard slope of the management standard during normal operation to prepare for the slope confirmed by this is set based on the wind speed assumed to act on the wind turbine or the amount of power assumed to be produced by the wind generator. Methods for monitoring structural integrity of support structures. According to paragraph 1,
Calculation of the stress is made by measuring a strain gauge installed on the support structure,
The stress in the normal range among the management standards at the time of emergency stop to prepare for the stress calculated by this is set based on the yield strength calculated by the material and thickness of the support structure to ensure the structural integrity of the support structure of the wind power generator. How to monitor. In clause 7,
A method for monitoring the structural integrity of a support structure of a wind turbine, characterized in that the stress calculated by the measurement of the strain gauge is verified at least once by the estimated wind speed at the location of the wind turbine. According to clause 8,
The estimated wind speed is calculated by the following formula using the measured wind speed confirmed at a height of 2 to 5 m above the ground of the support structure and the wind speed provided at a height of 10 m above the ground provided by the Korea Meteorological Administration. How to monitor integrity.
Maximum wind speed (m/s) = Min(25, Min (measured wind speed × 1.5), provided wind speed × 2.0)
Minimum wind speed (m/s) = Min(25, Max (measured wind speed × 0.5), provided wind speed × 1.0)
Estimated wind speed at wind turbine location = average value of maximum and minimum wind speeds According to paragraph 1,
Calculation of the stress is made by measuring a strain gauge installed on the support structure,
The normal range of the management standard during normal operation to prepare for the stress calculated by this is set based on the value calculated by the applied structural calculation with fatigue failure included as a variable. How to monitor integrity. According to clause 10,
A method for monitoring the structural integrity of a support structure of a wind turbine, characterized in that the stress calculated by the measurement of the strain gauge is verified by the amount of power produced by the wind turbine at least once. According to clause 11,
A method of monitoring the structural integrity of a support structure of a wind turbine, characterized in that the measurement of the amount of power produced for verification of the stress is indirectly made by installing a power meter on the power line.