Method for aligning the shafting of a hydroelectric power plant

Abstract

The invention relates to a method for aligning the shafting of a hydroelectric power plant, comprising the following steps: S1: setting the shafting into rotational motion; S2: while the shafting rotates, the control unit (9) continuously acquiring the signals generated by the vibration sensors (3.1, 3.2) and the angle sensor (4); S3: the control unit (9) analyzing the continuously acquired signals with respect to the concentricity of the shafting; S4: the control unit (9) outputting at least one notification; S5: stopping the rotational motion of the shafting; S6: if necessary, performing a corrective action.

Description

[0001] Method for aligning the shaft train of a hydroelectric power plant

[0002] The invention relates to a method for aligning the shaft of a hydroelectric power plant. The invention further relates to a control unit and a computer program for carrying out such a method, as well as a computer program product comprising such a computer program. The invention also relates to an operating method of a hydroelectric power plant.

[0003] Methods for aligning the shaft train of a hydroelectric power plant are known from the prior art. For example, documents SU 1 358042 A1 and SU 1 474318 A1 disclose such methods.

[0004] The object of the invention is to provide an alternative method which is characterized by the fact that the shaft train of a hydroelectric power plant can be aligned simply and reliably by it.

[0005] The problem is solved according to the invention by an embodiment according to the independent claim. Further advantageous embodiments of the present invention are found in the dependent claims.

[0006] The invention will be explained below with the aid of figures. The figures show, in detail:

[0007] Fig. 1: Shaft train of a hydroelectric power plant

[0008] Fig. 2: Sensor arrangement for detecting vibrations

[0009] Figure 1 shows an example of a shaft assembly of a hydroelectric power plant with the equipment required for carrying out the method according to the invention. Figure 1 shows a shaft assembly of a type commonly used in hydroelectric power plants. Therefore, the method according to the invention will be explained in more detail below using the arrangement shown in Figure 1 as an example. However, there are also hydroelectric power plants with differently designed shaft assemblies that are nevertheless suitable for carrying out the method according to the invention.

[0010] Figure 1 shows a shaft assembly with a vertically oriented axis of rotation, indicated by the dashed line. Hydropower plants with a horizontal axis of rotation are also known (and suitable for carrying out the method according to the invention). The shaft assembly further comprises an impeller of a hydraulic machine and a rotor of an electric machine. The impeller is designated 1 and the rotor 2. In general, the shaft assembly comprises at least one impeller 1 and at least one rotor 2.

[0011] Furthermore, the shaft assembly comprises at least two partial shafts. In Figure 1, the shaft assembly comprises three partial shafts, which are designated 5.1, 5.2, and 5.3. A partial shaft can be connected to the rotor 2 (as in partial shafts 5.1 and 5.2), to the impeller 1 (as in partial shaft 5.3), or to another partial shaft (as in partial shafts 5.2 and 5.3). The connection of the partial shafts to their respective counterparts can be achieved via flanges or by the respective partial shaft forming an integral part of the respective counterpart. In the latter case, the connection is permanent. In Figure 1, two flange connections are indicated by the rectangles designated 6. Thus, partial shaft 5.1 is connected to the rotor 2 via a flange 6, partial shaft 5.2 forms an integral part of the rotor 2, and partial shaft 5.3 forms an integral part of the impeller 1, and it is more common for the impeller to be connected to the associated partial shaft by a flange. The connection of two partial shafts to each other is always made via flanges 6. The aforementioned detachable connections (i.e., the connection via flanges) are referred to below as shaft assembly connections 6. In general, the shaft assembly comprises at least one shaft assembly connection 6.

[0012] The shaft assembly is rotatably connected to the stationary parts of the hydroelectric power plant by means of bearings. For this purpose, the shaft assembly comprises at least two radially acting bearings and one axially acting bearing, whereby one bearing can also combine radial and axial action. An axially acting bearing absorbs the thrust force and, in the case of vertical machines, the weight force. In horizontal machines, the weight force is absorbed by the radially acting bearings. The shaft assembly can therefore, for example, comprise a combined axial-radial bearing and at least one further radial bearing. The shaft assembly shown in Figure 1 comprises one axial-radial bearing, which is designated 8, and two radial bearings, which are designated 7.

[0013] The term "partial shaft" is further defined as one that is supported by at least one bearing. Parts of the shaft assembly that are not supported by at least one bearing are not considered "partial shafts".

[0014] To carry out the method according to the invention, the shaft train comprises a plurality of sensors or is equipped with a plurality of sensors. For each partial shaft, the shaft train includes at least one sensor arrangement for detecting vibrations. In Figure 1, the sensor arrangements for detecting vibrations are indicated by the rectangles labeled 3. The sensor arrangements 3 are arranged on the partial shafts such that they can detect the vibrations of the partial shafts. The structure of the sensor arrangements 3 and their orientation relative to a partial shaft are shown in Figure 2.

[0015] Furthermore, the shaft assembly includes at least one angle encoder as an additional sensor, which makes it possible to determine the rotational position of the shaft assembly from the angle encoder's signal. The angle encoder is indicated in Figure 1 by the rectangle labeled 4.

[0016] Furthermore, the shaft assembly includes a control unit, indicated by the rectangle labeled 9. The control unit 9 serves to acquire and evaluate the measurement signals from the sensors. For this purpose, the control unit 9 is connected to the sensors. The connection can be made via cable or wirelessly. The control unit 9 is also designed to provide the operator with a message regarding the alignment or concentricity of the shaft assembly. Figure 2 shows a sensor arrangement 3 for detecting vibrations. The sensor arrangement 3 comprises a first vibration sensor, labeled 3.1, and a second vibration sensor, labeled 3.2. The vibration sensors 3.1 and 3.2 are aligned so that they can detect the vibrations of a partial shaft. The partial shaft is labeled 5.The two vibration sensors are arranged at the same height axially along the partial shaft 5 and offset by 90° circumferentially along the partial shaft 5, so that the two sensors can detect the entire vibration of the partial shaft in a plane perpendicular to the shaft axis through the signal they detect. Due to the orthogonal arrangement of the sensors, the signals detected by them are linearly independent. All sensor arrangements 3 are configured in this way. All sensor arrangements can be oriented the same way, so that, viewed axially, the first sensors 3.1 and the second sensors 3.2 are positioned one above the other. The sensor arrangements can also be oriented differently. The orientation of sensors 3.1 and 3.2 of the sensor arrangements 3 must be known in each case, since the detected signals are used to calculate the orbits of the partial shafts.

[0017] It is advantageous to position the sensor arrays near the bearings. It is particularly advantageous if the vibration sensors of the sensor arrays are mechanically connected to the bearing housing, i.e., if both vibration sensors of a sensor array are connected to the housing of a bearing. This allows them to detect force transmission between the rotating and stationary parts of the bearing in question.

[0018] Examples of suitable vibration sensors include inductive proximity sensors or radar sensors.

[0019] The inventive method for aligning the shaft assembly of a hydroelectric power plant is described in more detail below. The method requires the following state of the hydroelectric power plant: The shaft assembly is installed in the turbine. The bearing shells of a suitable radial bearing are closed to their nominal diameter. It is advantageous if this bearing is located approximately in the middle of the shaft assembly. It is also advantageous if it is a combined axial-radial bearing. In the arrangement according to Figure 1, bearing 8 would be the best choice for this bearing. For all other radial bearings, the bearing shells are moved as far away as possible from the associated rotating part. These bearings are therefore fully open. In Figure 1, this would be the case for bearings designated 7. Furthermore, the vibration sensors were calibrated as necessary. The inventive method comprises the following steps:

[0020] - S1 : The wave train is set into rotational motion;

[0021] - S2: While the shaft train rotates, the signals generated by the vibration sensors 3.1 and 3.2 and the angle encoder 4 are continuously recorded by the control unit 9;

[0022] - S3: Evaluation of the continuously recorded signals with regard to the rotation of the shaft train by the control unit 9;

[0023] - S4: Output of at least one message by control unit 9;

[0024] - S5: Stopping the rotation of the shaft train;

[0025] - S6: If necessary, implement a corrective action;

[0026] The specified steps are repeated if a corrective action was required in the preceding step S6. If no corrective action was required in the preceding step S6, the procedure terminates, as the shaft assembly is then aligned. The bearing shells of the opened bearings can then be closed to their nominal diameter. Steps S1, S5, and S6 are performed by an operator. Whether a corrective action is performed in step S6 depends on the message from control unit 9 in the preceding step S4.

[0027] During the evaluation of the continuously acquired signals (step S3) with regard to the runout, the control unit performs, among other things, a consistency check of the signals. If the signals are consistent, the control unit 9 is able to calculate the runout of the shaft from the signals. A first message from the control unit 9 in step S4 can occur as soon as consistency has been determined. Afterwards, the runout calculation by the control unit 9 can be fully completed, and then another message can be issued by the control unit 9; that is, step S4 is performed in two temporally separated sub-steps. In this case, steps S3, S4, and possibly also S5 are executed partially in parallel. However, a single message in an undivided step S4 can also be issued only after the runout calculation by the control unit 9 has been completed.after completion of step S3. In this case, all steps are executed sequentially in the specified order.

[0028] It is advantageous if the control unit 9 outputs the calculated concentricity. Concentricity includes both the overall path of the shaft assembly and the orbits of the individual shafts at all locations where vibration assemblies are situated. Furthermore, the control unit 9 may indicate a necessary corrective action, including the angle at which the corrective action must be performed. Possible corrective actions include loosening a shaft assembly connection 6, which is then re-closed with a specific offset and / or tilt to improve concentricity.

[0029] The evaluation of the vibration signals from the vibration sensors to calculate the concentricity involves isolating the vibration signal component that has the same periodicity as the signal from the angle encoder. The vibration signal components thus determined from the two vibration sensors of a sensor arrangement yield the orbit of the respective partial shaft at the location of the sensor arrangement.

[0030] If the concentricity is so poor that force is transmitted to one of the open bearings, this can be detected by a disproportionate increase in the vibration signals from the corresponding vibration sensors and indicated by the control unit. It is advantageous if the control unit 9 includes a graphical user interface on which the concentricity data is displayed to the operator. The user interface could, for example, be a tablet wirelessly connected to the fixed part of the control unit 9. It is also advantageous if the data output via the graphical user interface uses colors to indicate the progress of the shaft alignment, e.g., a sequence of red, yellow, green, with green indicating the success of the procedure.

[0031] A particular advantage of the inventive method for aligning a shaft assembly lies in the fact that the vibration sensors of the sensor arrangements can be used not only for aligning the shaft assembly during commissioning, but also for monitoring the vibrations of the hydropower plant during its normal operation. The invention therefore also relates to an operating method of a hydropower plant in which the vibration sensors are used for aligning the shaft assembly during commissioning and for monitoring the vibrations of the shaft assembly during the normal operation of the hydropower plant.

[0032] Furthermore, the problem is solved by a computer program for carrying out one of the methods according to the invention, as well as by a computer program product with such a computer program.

[0033] Such a computer program is executed on a computer that is part of the control unit. If the control unit includes one or more separate graphical user interfaces, such as tablets, then part of the computer program is executed on the permanently installed part of the control unit, and other parts of the computer program are executed on the separate graphical user interface(s). In this case, the computer program product can also be designed in two or more parts. (Reference symbol list)

[0034] 1 impeller of a hydraulic machine

[0035] 2 Rotor of an electric machine

[0036] 3 Sensor arrangement for detecting vibrations 3.1 Vibration sensor

[0037] 3.2 Vibration sensor

[0038] 4 angle encoders

[0039] 5 partial wave

[0040] 5.1 Partial wave

[0041] 5.2 Partial wave

[0042] 5.3 Partial wave

[0043] 6 shaft connection

[0044] 7 radial bearings

[0045] 8 axial-radial bearings

[0046] 9 Control unit

Claims

Patent claims 1. Method for aligning the shaft train of a water power plant, wherein the shaft train comprises at least one impeller (1) of a hydraulic machine, at least one rotor (2) of an electric machine, at least two partial shafts (5.1, 5.2, 5.3) and at least one shaft train connection (6), and wherein the shaft train further comprises at least two radially acting bearings (7, 8) with a plurality of bearing shells, at least one axially acting bearing (8) and at least one angle sensor (4), characterized in that the shaft train comprises at least one sensor arrangement (3) for detecting vibrations for each partial shaft (5, 5.1, 5.2, 5.3), and wherein at least one sensor arrangement (3) is arranged on each partial shaft (5, 5.1, 5.2, 5.3) such that it can detect the vibrations of the associated partial shaft (5, 5.1, 5.2, 5.3), and wherein each sensor arrangement (3) comprises a first vibration sensor (3.1) and a second vibration sensor (3.2) comprises, and wherein the two vibration sensors (3.1, 3.2) are arranged at the same height in the axial direction of the associated partial shaft (5, 5.1, 5.2, 5.3) and offset by 90° in the circumferential direction of the associated partial shaft (5, 5.1, 5.2, 5.3) so that the signals detected by the vibration sensors (3.1, 3.2) are linearly independent, and wherein the shaft train comprises a control unit (9) configured to detect and evaluate the signals from the vibration sensors (3.1, 3.2) and the angle encoder (4), and wherein the method requires the following state of the hydroelectric power plant: The shaft train is installed in the hydroelectric turbine, the bearing shells of one radially acting bearing (8) are closed to nominal diameter, and the other radially acting bearings (7) are fully open; and wherein the method comprises the following steps:. S1: The wave train is set into rotational motion; S2: As the wave train rotates, the The signals generated by the vibration sensors (3.1, 3.2) and the angle encoder (4) are detected by the control unit (9); S3: Evaluation of the continuously recorded signals with regard to a complete rotation of the wave train by the control unit (9); S4: Output of at least one message by the control unit (9); S5: Stopping of the rotation of the shaft train; S6: If necessary, implement a corrective action; and wherein steps S1 to S6 are executed again if a corrective action was carried out in the preceding step S6, and wherein the execution of a corrective action in step S6 depends on the message in the preceding step S4.

2. Method according to claim 1, wherein the vibration sensors (3.1 , 3.2) of at least one sensor arrangement (3) are mechanically connected to a housing of a bearing (7, 8).

3. Method according to claim 1 or 2, wherein the vibration sensors (3.1 , 3.2) are designed as inductive proximity sensors.

4. Method according to claim 1 or 2, wherein the vibration sensors (3.1 , 3.2) are designed as radar sensors.

5. Method according to any of the preceding claims, wherein the control unit (9) comprises a graphical user interface.

6. Method for operating a hydroelectric power plant with a shaft train, and according to one of the preceding claims, wherein the shaft train comprises at least one impeller (1) of a hydraulic machine, at least one rotor (2) of an electric machine, at least two partial shafts (5.1, 5.2, 5.3) and at least one shaft train connection (6), and wherein the shaft train further comprises at least two radially acting bearings (7, 8) with a plurality of bearing shells, at least one axially acting bearing (8) and at least one angle sensor (4), characterized in that the shaft train comprises, for each partial shaft (5, 5.1, 5.2, 5.3) comprising at least one sensor arrangement (3) for detecting vibrations, and wherein at least one sensor arrangement (3) is arranged on each partial shaft (5, 5.1, 5.2, 5.3) such that it can detect the vibrations of the associated partial shaft (5, 5.1, 5.2, 5.3), and wherein each sensor arrangement (3) comprises a first vibration sensor (3.1) and a second vibration sensor (3.2), and wherein the two vibration sensors (3.1, 3.2) are arranged at the same height in the axial direction of the associated partial shaft (5, 5.1, 5.2, 5.3) and offset by 90° in the circumferential direction of the associated partial shaft (5, 5.1, 5.2, 5.3) so that the signals detected by the vibration sensors (3.1, 3.2) are linearly independent, and wherein the shaft train includes a control unit (9) comprises, which is designed to detect and evaluate the signals from the vibration sensors (3.1, 3.2) and the angle encoder (4), wherein the vibration sensors (3.1, 3.2) are used during commissioning to align the shaft train according to a method according to one of claims 1 to 5, and wherein the vibration sensors (3.1, 3.2) are used during normal operation to monitor the vibration of the shaft train.

7. Computer program for carrying out a method according to one of the preceding claims.

8. Computer program product comprising a computer program according to claim 7.

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