Comprehensive safety monitoring system and method for wind turbine generator tower

Abstract

The invention provides a comprehensive safety monitoring system and method for a wind turbine generator tower, and the device comprises a threaded structure, a sensing optical fiber, and four springs which have the same structure and are in the same stretching state in the initial state, and the side walls of two fixed parts in the threaded structure are provided with circumferential clamping grooves; the two ends of the first spring are clamped with the clamping grooves in the first fixing piece and fixedly connected with the inner side of the tower, and the two ends of the second spring are clamped with the clamping grooves in the second fixing piece through the heat insulation gaskets and fixedly connected with the outer side of the tower. The two ends of the third spring are fixedly connected with the simulation piece of the first fixing piece and the inner side of the tower respectively. The two ends of the fourth spring are fixedly connected with the simulation piece of the second fixing piece and the outer side of the tower respectively through heat insulation gaskets. When the tower vibrates, the four springs are bent, and the sensing optical fiber sections on the four springs are connected in series and then are connected with a strain measurement system. The vibration and temperature of the tower and the loosening condition of the thread structure can be monitored at the same time, and the structure is simple.

Description

Technical Field

[0001] The invention belongs to the field of wind turbine safety monitoring, and in particular relates to a wind turbine tower comprehensive safety monitoring system and method. Background Art

[0002] Wind turbines are devices that convert wind energy into electrical energy. As a clean energy source, wind energy has a wide range of applications. For the threaded structure used to fix the tower in the wind turbine, since the tower has a certain temperature, the temperature will affect the monitoring of the sensing optical fiber segment on the threaded structure, and the temperature may change; in addition, the tower will vibrate, and when the threaded structure becomes loose, the vibration will also affect the determination of the degree of looseness of the threaded structure, and the vibration will also change. Therefore, when using the existing threaded structure loosening monitoring device based on optical fiber sensing for monitoring, the monitoring accuracy of the loose threaded structure on the wind turbine is very low, and the temperature and vibration cannot be detected. Although there are optical fiber sensing devices that can detect temperature, vibration and strain at the same time, the structure is relatively complex and is not suitable for loosening detection of threaded structures on wind turbines. Summary of the invention

[0003] The present invention provides a wind turbine tower comprehensive safety monitoring system and method to solve the problem that the existing threaded structure loosening monitoring device based on optical fiber sensing has low monitoring accuracy due to the influence of wind turbine temperature and vibration, and the existing optical fiber sensing device that can simultaneously detect temperature, vibration and strain has a relatively complex structure and is not suitable for threaded structure loosening detection.

[0004] According to a first aspect of an embodiment of the present invention, there is provided a comprehensive safety monitoring system for a wind turbine tower, comprising a threaded structure, a sensing optical fiber, and a first spring, a second spring, a third spring, and a fourth spring with the same structure and the same initial tension state, wherein the threaded structure uses its bolts and nuts to fix the wind turbine tower, the nut or the nut of the bolt is used as the first fixing member of the threaded structure, and the nut or the nut of the bolt is used as the second fixing member of the threaded structure, the side walls of the first fixing member and the second fixing member are both provided with circumferential grooves, when the first fixing member and / or the second fixing member are loosened, the vertically arranged bolt vibrates back and forth along the vibration direction of the tower, and a first simulation member corresponding to the first fixing member and a second simulation member corresponding to the second fixing member are respectively fixed on the inner and outer sides of the tower;

[0005] The two ends of the first spring are respectively engaged with the slots on the first fixing member and fixedly connected to the inner side of the tower; the two ends of the second spring are respectively engaged with the slots on the second fixing member through a thermal insulation gasket and fixedly connected to the outer side of the tower; the two ends of the third spring are respectively fixedly connected to the first simulation member and the inner side of the tower; the two ends of the fourth spring are respectively fixedly connected to the second simulation member and the outer side of the tower through a thermal insulation gasket; in an initial state, the first spring and the second spring are symmetrical with respect to the tower, and the inclination directions of the first spring and the third spring, and the second spring and the fourth spring are respectively the same; when the tower vibrates, the four springs are all bent, and the sensing optical fiber segments on the four springs are connected in series and connected to the strain measurement system.

[0006] In an optional implementation, when the first fixing member and the second fixing member rotate, the clamping ends of the first spring and the second spring move in the corresponding clamping grooves, so that the first spring and the second spring are always on the same vertical plane.

[0007] According to a second aspect of an embodiment of the present invention, a monitoring method of the above-mentioned wind turbine tower integrated safety monitoring system is provided, and the strain measurement system performs the following steps:

[0008] Step S100, determining the vibration period of the fourth spring according to the time interval between two adjacent maximum strains measured by the sensing optical fiber segment on the fourth spring, and determining the vibration frequency of the tower according to the vibration period of the fourth spring;

[0009] Step S200, subtracting the maximum strain measured by the sensing optical fiber segment on the fourth spring from the maximum strain measured by the sensing optical fiber segment on the third spring to obtain the strain caused by the temperature of the tower;

[0010] Step S300, based on the correspondence between the locally stored temperature and the strain on the sensing optical fiber segment, the temperature of the tower is determined according to the obtained strain caused by the temperature;

[0011] Step S400: At the determined vibration frequency, there is a corresponding relationship between the amplitude of the second fixing member and the maximum strain of the sensing optical fiber segment on the second spring. Based on the locally stored corresponding relationship between the amplitude and the maximum strain at the determined vibration frequency, the amplitude of the second fixing member is determined according to the maximum strain measured by the sensing optical fiber segment on the second spring, thereby obtaining the looseness between the first fixing member and the second fixing member.

[0012] In an optional implementation, before step S400, the method further includes:

[0013] The minimum strain measured by the sensing optical fiber segment on the first spring is subtracted from the obtained strain caused by temperature to obtain a target strain, and it is determined whether the target strain is greater than the minimum strain measured by the sensing optical fiber segment on the second spring. If so, it means that the distance between the nut and the nut in the threaded structure is greater than the amplitude of the threaded structure at the determined vibration frequency, and step S600 is executed; otherwise, step S400 is executed;

[0014] Step S600: at the determined vibration frequency, there is a corresponding relationship between the amplitude of the second fixing member and the maximum strain of the sensing optical fiber segment on the second spring. Based on the locally stored corresponding relationship between the amplitude and the maximum strain at the determined vibration frequency, the amplitude of the second fixing member is determined according to the maximum strain measured by the sensing optical fiber segment on the second spring.

[0015] Step S700: There is a corresponding relationship between the vertical movement distance of the first spring from one position to another position and the minimum strain difference of the sensing optical fiber segment on the first spring. Based on the corresponding relationship between the vertical movement distance and the minimum strain difference stored locally, the minimum strain measured by the sensing optical fiber segment on the second spring is subtracted from the target strain to obtain the minimum strain difference. The vertical movement distance is determined according to the obtained minimum strain difference.

[0016] Step S800: Add the determined vertical movement distance to the amplitude of the second fixing member to obtain the looseness between the first fixing member and the second fixing member.

[0017] In another optional implementation, the minimum strain is the strain measured by the corresponding sensing optical fiber segment when the corresponding spring does not bend during the up and down vibration of the threaded structure.

[0018] The beneficial effects of the present invention are:

[0019] The present invention can simultaneously monitor the temperature, vibration frequency and looseness of the threaded structure of the tower in the wind turbine generator set, and both the structure and the method are very simple. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic structural diagram of an embodiment of the wind turbine tower comprehensive safety monitoring system of the present invention;

[0021] Figure 2 It is a schematic diagram of the arrangement of the sensing optical fiber segment on the spring of the present invention;

[0022] Figure 3 It is a schematic diagram of two vibration paths of the thread structure when the vibration frequency is constant;

[0023] Figure 4It is a flow chart of an embodiment of the comprehensive safety monitoring method for wind turbines of the present invention. DETAILED DESCRIPTION

[0024] In order to enable those skilled in the art to better understand the technical solutions in the embodiments of the present invention and to make the above-mentioned purposes, features and advantages of the embodiments of the present invention more obvious and understandable, the technical solutions in the embodiments of the present invention are further described in detail below in conjunction with the accompanying drawings.

[0025] In the description of the present invention, unless otherwise specified and limited, it should be noted that the term "connection" should be understood in a broad sense. For example, it can be a mechanical connection or an electrical connection, or it can be the internal connection between two elements. It can be a direct connection or an indirect connection through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to specific circumstances.

[0026] See also Figure 1 , is a schematic diagram of the structure of an embodiment of the wind turbine tower comprehensive safety monitoring system of the present invention. Figure 2 As shown, the wind turbine tower integrated safety monitoring system may include a threaded structure, a sensing optical fiber 5, and a first spring 1, a second spring 2, a third spring 3, and a fourth spring 4 with the same structure and the same initial tension state. The threaded structure uses its bolts 13 and nuts to fix the wind turbine tower 6, and the nut of the nut or bolt 13 is used as the first fixing member 11 of the threaded structure, and the nut of the bolt is used as the second fixing member 12 of the threaded structure. The side walls of the first fixing member 11 and the second fixing member 12 are both provided with circumferential grooves 14. When the first fixing member 11 and / or the second fixing member 12 are loosened, the vertically arranged bolt 13 vibrates back and forth along the vibration direction of the tower, and a first simulation member 15 corresponding to the first fixing member 11 and a second simulation member 16 corresponding to the second fixing member 12 are respectively fixed on the inner and outer sides 6 of the tower.

[0027] The two ends of the first spring 1 are respectively engaged with the slots 14 on the first fixing member 11 and fixedly connected to the inner side of the tower, and the two ends of the second spring 2 are respectively engaged with the slots 14 on the second fixing member 12 through thermal insulation gaskets and fixedly connected to the outer side of the tower; the two ends of the third spring 3 are respectively fixedly connected to the first simulation member 15 and the inner side of the tower, and the two ends of the fourth spring 4 are respectively fixedly connected to the second simulation member 16 and the outer side of the tower through thermal insulation gaskets; in the initial state, the first spring 1 and the second spring 2 are symmetrical with respect to the tower, and the inclination directions of the first spring 1 and the third spring 3, the second spring 2 and the fourth spring 4 are respectively the same; when the tower 6 vibrates, the four springs are bent, and the sensing optical fiber segments on the four springs are connected in series and connected to the strain measurement system. The strain measurement system determines the temperature, vibration frequency and looseness of the tower according to the strain detected by the sensing optical fiber segments on the four springs. Among them, the sensing optical fiber segments on the first spring 1 and the second spring 2 can be connected through the vertical through hole 7 opened on the tower 6.

[0028] The present invention provides four springs, and corresponding first simulation members and second simulation members are provided on the inner and outer sides of the tower frame for the first fixing members and the second fixing members located on the inner and outer sides of the tower frame. Since the four springs will bend synchronously under the action of inertia when the tower frame vibrates, the two ends of the third spring are fixedly connected to the first simulation member and the inner side of the tower frame respectively, so that the strain of the sensing optical fiber segment on the third spring is only affected by the vibration and temperature of the tower frame, and the two ends of the fourth spring are fixedly connected to the second simulation member and the outer side of the tower frame respectively through a heat insulation gasket, so that the strain of the sensing optical fiber segment on the fourth spring is only affected by the vibration of the tower frame.

[0029] Since the structures and initial states of the four springs are the same, and in the initial state, the first spring and the second spring are symmetrical with respect to the tower frame, and the first spring has the same inclination direction as the third spring, the second spring and the fourth spring, respectively, the strain of the sensing fiber segment of the third spring minus the strain of the sensing fiber segment of the fourth spring can be obtained to obtain the strain of the sensing fiber segment of the third spring that is only affected by temperature; since the spring will bend as the tower frame vibrates, the sensing fiber of the fourth spring detects two maximum strains within one vibration cycle, and therefore the vibration cycle of the tower frame can be determined according to the time interval between the two adjacent maximum strains measured by the sensing fiber segment of the fourth spring, thereby determining the vibration frequency of the tower frame; in addition, the relationship between the temperature and the strain on the sensing fiber segment can be simulated, and the maximum strain of the sensing fiber segment of the third spring can be subtracted from the maximum strain of the sensing fiber segment of the fourth spring, and the temperature can be determined according to the strain obtained by subtraction.

[0030] Since the side walls of the first fixing member and the second fixing member are both provided with circumferential slots, the first spring and the second spring are respectively engaged with the slots on the corresponding fixing members, and the first spring and the second spring are both in a stretched state in their initial state, when the nut and the screw rotate, the engaging ends of the two springs will only move in the slots under the action of tension, and will not deform with the rotation of the nut and the screw, that is, the axial stretching of the two springs is only determined by the up and down movement of the corresponding fixing members. Figure 3 Two situations are shown. Figure 3 (a) is the vibration condition of the threaded structure when the amplitude (i.e. the maximum amplitude of vibration) of the threaded structure is greater than or equal to the actual distance between the nut and the cap at the corresponding vibration frequency. Figure 3 (a) It can be seen that when the threaded structure vibrates to the middle position, the first spring 1 and the second spring 2 are not bent, the first fixing member 11 and the second fixing member 12 are at the same distance from the tower 6, and the strain measured by the sensing fiber segment on the first spring 1 and the second spring 2 is the minimum strain in the measurement cycle. Since both ends of the second spring 2 are connected to the second fixing member 12 and the outer side of the tower respectively through a heat insulating gasket, the strain of the sensing fiber segment on the second spring 2 is not affected by temperature. Therefore, the minimum strain measured by the sensing fiber segment on the first spring 1 minus the strain caused by temperature is equal to the minimum strain measured by the sensing fiber segment on the second spring 2. The measurement cycle is the maximum time allowed for the threaded structure to complete the up and down vibration.

[0031] Figure 3 (b) is the vibration of the threaded structure when the amplitude of the threaded structure is smaller than the actual distance between the nuts at the corresponding vibration frequency. Figure 3 (b) It can be seen that when the threaded structure vibrates to the middle position, the first spring 1 and the second spring 2 do not bend, the first fixing member 11 and the second fixing member 12 are at different distances from the tower 6, and the strain measured by the sensing optical fiber segments on the first spring 1 and the second spring 2 is the minimum strain within the measurement period, and the strain difference obtained by subtracting the strain caused by temperature from the minimum strain measured by the sensing optical fiber on the first spring 1 is greater than the minimum strain measured by the sensing optical fiber segment on the second spring 2, that is, the strain of the sensing optical fiber segment on the first spring 1 caused only by the loose threaded structure is greater than the strain of the sensing optical fiber segment on the second spring 2 caused only by the loose threaded structure.

[0032] for Figure 3In the case shown in (a), when the vibration frequency is constant, the looser the first fixing member and the second fixing member are, the larger the distance between them is, the larger the amplitude of the second fixing member is, and when the amplitude of the second fixing member is different, the maximum strain of the sensing fiber segment on the second spring is different. That is, when the vibration frequency is constant, there is a corresponding relationship between the amplitude of the second fixing member and the maximum strain of the sensing fiber segment on the second spring, so the corresponding relationship can be simulated, and after the maximum strain of the sensing fiber segment on the second spring is measured, the amplitude of the second fixing member can be obtained according to the corresponding relationship, thereby obtaining the looseness of the first fixing member and the second fixing member.

[0033] for Figure 3 (b) shows the situation that when the strain measured by the sensing fiber section on the first spring and the second spring is the smallest, the first spring and the second spring do not bend, and the minimum strain can directly reflect the position of the first fixing member and the second fixing member in the vertical direction. Therefore, there is a corresponding relationship between the vertical movement distance of the first spring from one position to another and the minimum strain difference of the sensing fiber section on the first spring, and the corresponding relationship can be simulated. After the minimum strain is measured by the sensing fiber section on the first spring, the minimum strain can be subtracted from the strain caused by temperature to obtain the target strain, and the minimum strain measured by the sensing fiber section on the second spring can be subtracted from the target strain to obtain the minimum strain difference. According to the obtained minimum strain difference, the vertical movement distance is determined. Thereafter, the determined vertical movement distance can be added to the amplitude of the second fixing member to obtain the looseness between the first fixing member and the second fixing member.

[0034] It can be seen from the above embodiments that the present invention can simultaneously monitor the temperature, vibration frequency and looseness of the threaded structure of the tower through the sensing optical fiber, and the structure and method are very simple.

[0035] In addition, the present invention also provides a monitoring method for the above-mentioned wind turbine tower integrated safety monitoring system, in which the strain measurement system performs the following steps:

[0036] Step S100: Determine the vibration period of the fourth spring according to the time interval between two adjacent maximum strains measured by the sensing optical fiber segment on the fourth spring, and determine the vibration frequency of the tower according to the vibration period of the fourth spring.

[0037] Step S200, subtracting the maximum strain measured by the sensing optical fiber segment on the fourth spring from the maximum strain measured by the sensing optical fiber segment on the third spring to obtain the strain caused by the temperature of the tower;

[0038] Step S300: There is a corresponding relationship between the temperature of the tower and the strain on the sensing optical fiber segment. Based on the locally stored corresponding relationship between the temperature and the strain on the sensing optical fiber segment, the temperature of the tower is determined according to the obtained strain caused by the temperature.

[0039] Step S400: At the determined vibration frequency, there is a corresponding relationship between the amplitude of the second fixing member and the maximum strain of the sensing optical fiber segment on the second spring. Based on the locally stored corresponding relationship between the amplitude and the maximum strain at the determined vibration frequency, the amplitude of the second fixing member is determined according to the maximum strain measured by the sensing optical fiber segment on the second spring, thereby obtaining the looseness between the first fixing member and the second fixing member.

[0040] Before step S400, the method further includes:

[0041] The target strain is obtained by subtracting the strain caused by temperature from the minimum strain measured by the sensing optical fiber segment on the first spring, and judging whether the target strain is greater than the minimum strain measured by the sensing optical fiber segment on the second spring. If so, it indicates that the distance between the nut and the nut in the threaded structure is greater than the amplitude of the threaded structure at the determined vibration frequency, and step S600 is executed; otherwise, step S400 is executed; the minimum strain is the strain measured by the corresponding sensing optical fiber segment when the corresponding spring does not bend during the up and down vibration of the threaded structure.

[0042] Step S600: At the determined vibration frequency, there is a corresponding relationship between the amplitude of the second fixing member and the maximum strain of the sensing optical fiber segment on the second spring. Based on the locally stored corresponding relationship between the amplitude and the maximum strain at the determined vibration frequency, the amplitude of the second fixing member is determined according to the maximum strain measured by the sensing optical fiber segment on the second spring.

[0043] Step S700: There is a corresponding relationship between the vertical movement distance of the first spring from one position to another and the minimum strain difference of the sensing optical fiber segment on the first spring. Based on the corresponding relationship between the vertical movement distance and the minimum strain difference stored locally, the minimum strain measured by the sensing optical fiber segment on the second spring is subtracted from the target strain to obtain the minimum strain difference. The vertical movement distance is determined based on the obtained minimum strain difference.

[0044] Step S800: Add the determined vertical movement distance to the amplitude of the second fixing member to obtain the looseness between the first fixing member and the second fixing member.

[0045] It can be seen from the above embodiments that the present invention can simultaneously monitor the temperature, vibration frequency and looseness of the threaded structure of the tower in the wind turbine generator set through the sensing optical fiber, and the structure and method are very simple.

[0046] Those skilled in the art will readily appreciate other embodiments of the present invention after considering the specification and practicing the invention disclosed herein. This application is intended to cover any variations, uses or adaptations of the present invention that follow the general principles of the present invention and include common knowledge or customary techniques in the art that are not disclosed by the present invention. The specification and examples are to be considered exemplary only, and the true scope and spirit of the present invention are indicated by the following claims.

[0047] It will be appreciated that the invention is not limited to the precise construction that has been described above and shown in the drawings and that various modifications and changes may be made without departing from its scope. The scope of the invention is governed solely by the appended claims.

Claims

1. A wind turbine tower comprehensive safety monitoring system, characterized in that: It comprises a threaded structure, a sensing optical fiber, and a first spring, a second spring, a third spring and a fourth spring with the same structure and the same initial tension state. The threaded structure uses its bolts and nuts to fix the wind turbine tower. The nut or the nut of the bolt is used as the first fixing piece of the threaded structure, and the nut or the nut of the bolt is used as the second fixing piece of the threaded structure. The side walls of the first fixing piece and the second fixing piece are both provided with circumferential grooves. When the first fixing piece and / or the second fixing piece are loosened, the vertically arranged bolt vibrates back and forth along the vibration direction of the tower. A first simulation piece corresponding to the first fixing piece and a second simulation piece corresponding to the second fixing piece are respectively fixed on the inner and outer sides of the tower. The two ends of the first spring are respectively engaged with the slots on the first fixing member and fixedly connected to the inner side of the tower; the two ends of the second spring are respectively engaged with the slots on the second fixing member through a thermal insulation gasket and fixedly connected to the outer side of the tower; the two ends of the third spring are respectively fixedly connected to the first simulation member and the inner side of the tower; the two ends of the fourth spring are respectively fixedly connected to the second simulation member and the outer side of the tower through a thermal insulation gasket; in an initial state, the first spring and the second spring are symmetrical with respect to the tower, and the inclination directions of the first spring and the third spring, and the second spring and the fourth spring are respectively the same; when the tower vibrates, the four springs are all bent, and the sensing optical fiber segments on the four springs are connected in series and connected to the strain measurement system.

2. The system according to claim 1, characterized in that When the first fixing member and the second fixing member rotate, the clamping ends of the first spring and the second spring move in the corresponding clamping grooves, so that the first spring and the second spring are always on the same vertical plane.

3. A monitoring method for the wind turbine tower comprehensive safety monitoring system according to claim 1 or 2, characterized in that: The strain measurement system performs the following steps: Step S100, determining the vibration period of the fourth spring according to the time interval between two adjacent maximum strains measured by the sensing optical fiber segment on the fourth spring, and determining the vibration frequency of the tower according to the vibration period of the fourth spring; Step S200, subtracting the maximum strain measured by the sensing optical fiber segment on the fourth spring from the maximum strain measured by the sensing optical fiber segment on the third spring to obtain the strain caused by the temperature of the tower; Step S300, based on the correspondence between the locally stored temperature and the strain on the sensing optical fiber segment, the temperature of the tower is determined according to the obtained strain caused by the temperature; Step S400: At the determined vibration frequency, there is a corresponding relationship between the amplitude of the second fixing member and the maximum strain of the sensing optical fiber segment on the second spring. Based on the locally stored corresponding relationship between the amplitude and the maximum strain at the determined vibration frequency, the amplitude of the second fixing member is determined according to the maximum strain measured by the sensing optical fiber segment on the second spring, thereby obtaining the looseness between the first fixing member and the second fixing member.

4. The method according to claim 3, characterized in that Before step S400, the method further includes: The minimum strain measured by the sensing optical fiber segment on the first spring is subtracted from the obtained strain caused by temperature to obtain a target strain, and it is determined whether the target strain is greater than the minimum strain measured by the sensing optical fiber segment on the second spring. If so, it means that the distance between the nut and the nut in the threaded structure is greater than the amplitude of the threaded structure at the determined vibration frequency, and step S600 is executed; otherwise, step S400 is executed; Step S600: at the determined vibration frequency, there is a corresponding relationship between the amplitude of the second fixing member and the maximum strain of the sensing optical fiber segment on the second spring. Based on the locally stored corresponding relationship between the amplitude and the maximum strain at the determined vibration frequency, the amplitude of the second fixing member is determined according to the maximum strain measured by the sensing optical fiber segment on the second spring. Step S700: There is a corresponding relationship between the vertical movement distance of the first spring from one position to another position and the minimum strain difference of the sensing optical fiber segment on the first spring. Based on the corresponding relationship between the vertical movement distance and the minimum strain difference stored locally, the minimum strain measured by the sensing optical fiber segment on the second spring is subtracted from the target strain to obtain the minimum strain difference. The vertical movement distance is determined according to the obtained minimum strain difference. Step S800: Add the determined vertical movement distance to the amplitude of the second fixing member to obtain the looseness between the first fixing member and the second fixing member.

5. The method according to claim 4, characterized in that The minimum strain is the strain measured by the corresponding sensing optical fiber segment when the corresponding spring does not bend during the up and down vibration of the threaded structure.

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