A zero-weight dynamic balancing method for vertical hydro-generator sets

Abstract

The present invention discloses a zero-counterweight method for dynamic balancing of a vertical hydro-turbine generator set, relating to the technical field of hydro-turbine generator sets. The present invention performs eccentricity control during the rotor assembly stage. Specifically, the present invention controls the rotor mass eccentricity during the rotor assembly process, controlling the rotor imbalance caused by assembly to a negligible range. Simultaneously, the imbalance caused by the rotor's asymmetric structure is calculated. Counterweighting is applied during the rotor assembly process based on the calculated results, significantly reducing or eliminating the rotor imbalance during the unit installation stage. This ensures that the unit's vibration after startup meets the contract requirements, thereby achieving the zero-counterweight purpose during the unit's dynamic balancing test stage.

Description

Technical Field

[0001] The present invention relates to the technical field of hydro-generator sets, in particular to the technical field of vertical hydro-generator sets, and more specifically to a dynamic balancing zero-weight method for vertical hydro-generator sets. Background Art

[0002] Among the hydroelectric generator sets put into operation in my country, vertical hydroelectric generator sets account for the largest proportion. Large hydropower stations such as the Three Gorges, Xiluodu, Wudongde, and Baihetan all use vertical hydroelectric generator sets. The key indicator for evaluating the stability of hydroelectric generator sets is unit vibration. In order to ensure that the unit vibration meets the contract requirements, the existing technology is to reduce the rotor imbalance by applying dynamic balancing weights during the unit commissioning phase, thereby reducing the unit vibration caused by the rotor imbalance. In the existing technology, the implementation plan of dynamic balancing weights for vertical hydroelectric generator sets is as follows:

[0003] 1. After the unit is installed and the conditions for startup and commissioning are met, install the dynamic balance weight test equipment, including vibration measurement sensors and data analysis instruments;

[0004] 2. Start the unit and monitor the vibration of the unit. If the vibration of the unit meets the requirements, increase the speed to the rated speed. Otherwise, analyze the vibration data and calculate the rotor imbalance, and adjust the weight according to the calculation results.

[0005] 3. After the unit reaches the rated speed, the overspeed test shall be carried out if the vibration meets the requirements. Otherwise, the rotor unbalance amount shall be analyzed and calculated based on the idling vibration data, and the weight shall be balanced according to the calculated results.

[0006] 4. After the unit is connected to the grid and carries the rated load, the load rejection test shall be carried out if the vibration meets the requirements. Otherwise, the rotor unbalance amount shall be analyzed and calculated based on the rated load vibration data, and the weight shall be continued according to the calculated results;

[0007] 5. For pumped storage units, the vibration data of the pump operating conditions should also be analyzed, and counterweights should be added if necessary;

[0008] 6. After the vibration of each operating condition of the unit meets the contract requirements, the counterweight block shall be effectively fixed (usually by welding).

[0009] Each balancing operation involves machining the counterweights based on the calculated rotor imbalance and then installing them. The general steps for balancing weight installation are: isolate the unit - remove the windshield - crank the rotor (rotate the rotor where the counterweights will be added to the area where the windshields will be removed) - install the counterweights - reinstall the windshield - and then restore the unit. A single balancing operation requires 5-10 people and takes 5-8 hours. The entire dynamic balancing process consumes significant manpower and material resources, taking up significant time during the unit commissioning process and delaying the unit's commissioning. Furthermore, frequent installation and removal of the windshield and rotor access during commissioning are detrimental to safe unit operation. Summary of the Invention

[0010] In order to overcome the defects and deficiencies in the above-mentioned prior art, the present invention provides a method for dynamic balancing of a vertical hydro-turbine generator set with zero counterweight. The purpose of the present invention is to shorten the installation and commissioning period of the vertical hydro-turbine generator set and save manpower and material investment costs. The dynamic balancing zero counterweight described in the present invention means that the rotor of the generator set assembled by the method of the present invention does not need to be equipped with counterweights during the dynamic balancing test stage. The present invention performs eccentricity control during the rotor assembly stage. Specifically, the present invention controls the eccentricity of the rotor mass during the rotor assembly process, controls the imbalance of the rotor caused by assembly to a negligible range, and calculates the imbalance caused by the asymmetric structure of the rotor at the same time. According to the calculation results, counterweights are applied during the rotor assembly process, and the rotor imbalance is greatly reduced or eliminated during the unit installation stage, so that the vibration of the unit after startup meets the contract requirements, thereby achieving the purpose of zero counterweight during the unit dynamic balancing test stage.

[0011] In order to solve the problems existing in the above-mentioned prior art, the present invention is achieved through the following technical solutions:

[0012] The present invention provides a zero-counterweight method for dynamic balancing of a vertical hydro-generator set, the method comprising the following steps:

[0013] S1. During the rotor assembly stage, the rotor assembly quality eccentricity control is performed to control the rotor imbalance caused by assembly to a negligible range;

[0014] S2. Calculate the rotor unbalance caused by the asymmetric structure on the rotor;

[0015] S3. Formulate a rotor weighting plan based on the rotor imbalance calculated in step S2;

[0016] S4. Implementing the rotor weight balancing scheme developed in step S3 on the rotor;

[0017] S5. After the rotor is assembled with counterweights, the counterweight effect of the rotor is verified.

[0018] Further preferably, in step S1, the rotor assembly mass eccentricity control specifically includes:

[0019] Yoke stacking eccentricity control, yoke stacking mass eccentricity control and pole hanging mass eccentricity control.

[0020] More preferably, the yoke stacking eccentricity control specifically refers to raising the yoke eccentricity standard to ≯0.1 mm to reduce the rotor imbalance caused by the yoke eccentricity.

[0021] More preferably, the yoke stacking mass eccentricity control specifically refers to subdividing the yoke punching weighing classification gradient into 0.2Kg, and controlling the mass deviation of each layer of yoke punching within 0.2Kg, so as to control the overall mass eccentricity of the yoke after stacking, thereby reducing the rotor imbalance caused by the yoke stacking mass eccentricity.

[0022] Further preferably, the pole mounting mass eccentricity control specifically refers to increasing the mass deviation standard of the two poles mounted in the symmetrical direction to ≯1Kg when the pole is mounted; when the current pole weight cannot meet the mass deviation standard requirement, vector synthetic counterweight is used to reduce the rotor imbalance caused by the pole mounting mass eccentricity.

[0023] Further preferably, in step S2, the asymmetric structure on the rotor includes a rotor lead assembly and a rotor bracket access hole; in step S2, the unbalance amounts caused by the rotor lead assembly and the rotor bracket access hole are calculated separately.

[0024] Further preferably, the unbalance caused by the rotor lead assembly and the rotor bracket entry manhole is calculated respectively according to the formula U=│Gr│∠α, where G represents the unbalanced mass, that is, the mass of the rotor lead assembly and the rotor bracket entry manhole; r is the radius where the unbalanced mass exists, that is, the radius of the center of gravity of the rotor lead assembly and the rotor bracket entry manhole; α is the circumferential reference angle, which is the angle between the unbalanced mass and the +X axis.

[0025] More preferably, the rotor lead assembly is divided into arc segment lead assembly and straight segment lead assembly, and the formula U X =│Gr│cosα and U Y =│Gr│sinαThe lead and clip assembly unbalance vectors of the arc segment lead assembly are decomposed into the X and Y coordinate axes respectively, and the arc segment lead assembly unbalance U1=│U1│∠α1 is obtained by vector synthesis; the straight segment lead assembly unbalance U2=│U2│∠α2 is calculated in the same way.

[0026] Further preferably, in step S3, the formulating of the rotor matching plan specifically refers to installing the rotor counterweight on the keyway of the tangential key on the inner wall of the rotor yoke, calculating the counterweight mass M1 required for the arc segment rotor lead assembly according to the formula M1=│U1│ / R, where R is the counterweight installation radius, the counterweight installation angle is α1+180°, and the counterweight installation height is in the same cross section as the arc segment rotor lead assembly;

[0027] The same method is used to calculate the mass M2 of the counterweight required for the straight segment rotor lead assembly, with an angle of α2+180° and a height at the same cross section as the straight segment rotor lead assembly;

[0028] If there is a rotor bracket entry hole on the rotor, the mass M3 of the counterweight required for the rotor bracket entry hole is calculated according to the formula M3=│U3│ / R, the angle α3, and the height are in the same cross section as the rotor bracket entry hole.

[0029] More preferably, in the rotor balancing weight scheme formulated in step S3, the balancing weight block installation angle cannot be used to install the balancing weight block, and the balancing weight mass is decomposed into adjacent installable positions.

[0030] Compared with the prior art, the beneficial technical effects brought about by the present invention are as follows:

[0031] 1. The method of the present invention is performed during rotor assembly and does not occupy the linear period of unit installation and commissioning. Compared with the existing technology, the unit can be put into operation earlier, creating considerable economic benefits. The method of the present invention is performed during rotor assembly, eliminating the need for multiple dynamic balancing weights, unit isolation, windshield removal, and turning operations. Only one static balancing weight is performed during rotor assembly, significantly reducing the manpower and material resources invested compared to the existing technology. Compared with the existing technology, the method of the present invention reduces the number of operations above the rotor during commissioning, effectively reducing the safety risks of the unit.

[0032] 2. In the present invention, during the rotor assembly stage, by controlling the yoke stacking eccentricity standard, the yoke stacking mass eccentricity standard, and the pole mounting mass eccentricity standard, the yoke eccentricity standard is raised to ≯0.1mm, the yoke punching weighing classification gradient is refined to 0.2kg, and the pole mass deviation standard is raised to ≯1kg, thereby reducing the rotor imbalance caused by yoke eccentricity, the rotor imbalance caused by yoke stacking mass eccentricity, and the rotor imbalance caused by pole mounting mass eccentricity. Through the above means, it can be effectively ensured that the rotor imbalance caused by assembly is controlled within a negligible range.

[0033] 3. In the present invention, the composition of the asymmetric structure on the rotor of a vertical hydro-turbine generator set is analyzed, primarily comprising the rotor lead assembly and the rotor bracket access manhole. The rotor lead assembly comprises a lead and wire clamp assembly. When calculating the imbalance, the fact that the rotor lead assembly and the rotor bracket are not at the same height is taken into account. Therefore, the imbalance caused by the rotor lead assembly and the imbalance caused by the rotor bracket are calculated separately. The specific structure of the rotor lead assembly is also taken into account. The rotor lead assembly includes multiple lead segments and multiple wire clamps with different distribution radii and circumferential reference angles. For ease of calculation, the lead assembly is divided into arc segment lead assembly and straight segment lead assembly. Counterweight schemes are then formulated based on the imbalance caused by the arc segment lead assembly and the straight segment lead assembly, respectively, to ensure the effectiveness of the counterweight scheme.

[0034] 4. According to the rotor counterweight scheme developed using the present method, the prepared counterweights are installed on the rotor yoke at the calculated angle and height and secured according to the drawing. After the unit is started, the runout data is checked using dedicated measuring equipment or unit status monitoring equipment to verify that it meets the contract requirements. This present invention only requires one static balancing operation during rotor assembly, significantly reducing manpower and material resources compared to existing technologies. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 This is a flow chart of a zero-counterweight method for dynamic balancing of a vertical hydro-generator set according to the present invention;

[0036] Figure 2 This is a cross-sectional view of the installation of the counterweight block of the vertical hydro-generator set of the present invention;

[0037] Figure 3 This is a top view of the installation of the counterweight block of the vertical hydro-generator set of the present invention;

[0038] Figure numerals: 1. rotor bracket, 2. yoke, 3. counterweight, 4. magnetic pole, 5. straight segment lead assembly, 6. arc segment lead assembly, 7. straight segment lead counterweight, 8. arc segment lead counterweight. DETAILED DESCRIPTION

[0039] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the drawings in the present invention specification. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0040] As a preferred embodiment of the present invention, refer to the attached Figure 1 As shown, this embodiment discloses a method for dynamic balancing of a vertical hydro-generator set with zero counterweight, the method comprising the following steps:

[0041] S1. During the rotor assembly stage, the rotor assembly quality eccentricity control is performed to control the rotor imbalance caused by assembly to a negligible range;

[0042] S2. Calculate the rotor unbalance caused by the asymmetric structure on the rotor;

[0043] S3. Formulate a rotor weighting plan based on the rotor imbalance calculated in step S2;

[0044] S4. Implementing the rotor weight balancing scheme developed in step S3 on the rotor;

[0045] S5. After the rotor is assembled with counterweights, the counterweight effect of the rotor is verified.

[0046] It is important to note that the present invention's solution is implemented during the rotor assembly phase, not during the dynamic balancing and commissioning phase after rotor assembly. The "zero-weight" dynamic balancing method described in this invention refers to the method used to perform rotor assembly. No additional weights are required during the rotor dynamic balancing and commissioning phase, thus constituting the zero-weight dynamic balancing method.

[0047] In this embodiment, the rotor imbalance of a vertical hydro-turbine generator set is primarily caused by the following factors: first, rotor material non-uniformity, including material deviations and component processing deviations; second, rotor assembly mass eccentricity, including mass eccentricity of the rotor yoke 1 stacking and mass eccentricity of the pole 4 mounting; and third, the asymmetric structure of the rotor. Thanks to iterations of processing equipment and improvements in processing technology, rotor material non-uniformity has been significantly improved, making the resulting rotor imbalance negligible. The mass eccentricity caused by the stacking of the rotor yoke 2 during assembly cannot be accurately calculated and can only be controlled during the yoke 2 stacking process. The imbalance caused by the asymmetric structure of the rotor can be calculated. This embodiment controls rotor mass eccentricity during the rotor assembly process, keeping the rotor imbalance caused by assembly within a negligible range. Simultaneously, the imbalance caused by the asymmetric structure of the rotor is calculated. Based on the calculated results, counterweighting is applied during the rotor assembly process, significantly reducing or eliminating rotor imbalance during the unit installation phase. This ensures that the unit vibration meets the contract requirements after startup, achieving zero counterweight for dynamic balancing of the unit.

[0048] As a preferred implementation of this embodiment, the rotor mass eccentricity is controlled during the rotor assembly stage, and the unbalance amount of the rotor caused by assembly is controlled within a negligible range. Specifically:

[0049] When stacking yokes, the yoke eccentricity standard is increased from the current ≯0.2mm to ≯0.1mm to reduce the rotor imbalance caused by yoke eccentricity;

[0050] Yoke stacking mass eccentricity control: For conventional laminated yokes, the yoke punching weighing classification gradient is subdivided from 2Kg to 0.2Kg. The mass deviation of each layer of yoke punching is controlled within 0.2Kg to control the overall mass eccentricity of the yoke after stacking, thereby reducing the rotor imbalance caused by the mass eccentricity of the yoke stacking;

[0051] When mounting the magnetic poles, the mass deviation standard of the two magnetic poles mounted in the symmetrical direction is increased from the current ≯2Kg to ≯1Kg. If the existing magnetic pole weight cannot meet the requirements, vector synthetic counterweights can be used to reduce the rotor imbalance caused by the eccentricity of the magnetic pole mounting mass.

[0052] like Figure 2As shown, the asymmetric structures on the rotor of a vertical hydro-turbine generator set primarily include the rotor lead assembly (including the lead and wire clamp assembly) and the rotor bracket 1 access hole. The rotor unbalance caused by the rotor lead assembly and rotor bracket access hole is calculated using the formula U=│Gr│∠α, where G represents the unbalance mass, i.e., the mass of the rotor lead assembly and rotor bracket access hole; r is the radius where the unbalance mass exists, i.e., the radius of the center of gravity of the rotor lead assembly and rotor bracket access hole; and α is the circumferential reference angle, generally the angle between the unbalance mass and the +X axis. Since the rotor lead assembly and rotor bracket are not at the same height, they must be calculated separately.

[0053] like Figure 3 As shown, the rotor lead assembly includes multiple lead segments and multiple wire clips, and the distribution radius and circumferential reference angle are different. For the convenience of calculation, the lead assembly is usually divided into arc segment lead assembly 6 and straight segment lead assembly 5. X =│Gr│cosα and U Y =│Gr│sinαThe lead and clip assembly unbalance vectors of the arc segment lead assembly are decomposed into the X and Y coordinate axes respectively, and the arc segment lead assembly unbalance U1=│U1│∠α1 is obtained by vector synthesis; the straight segment lead assembly unbalance U2=│U2│∠α2 is calculated in the same way.

[0054] like Figure 3 As shown, the rotor counterweight 3 of a conventional vertical hydro-turbine generator is typically installed in the keyway of the tangential key on the inner wall of the rotor yoke. The mass M1 of the circular arc lead counterweight 8 required for the arc-segment rotor lead assembly is calculated using the formula M1=│U1│ / R, where R is the counterweight installation radius. The counterweight installation angle is α1+180°, and the height of the counterweight installation should be aligned with the cross-section of the arc-segment rotor lead assembly as much as possible. The mass M2 of the straight-segment lead counterweight 7 required for the straight-segment rotor lead assembly is calculated using the same method, using an angle of α2+180° and a height aligned with the cross-section of the straight-segment rotor lead assembly as much as possible. If a rotor bracket access manhole is provided, the mass M3 of the counterweight required for the rotor bracket access door should be calculated using the formula M3=│U3│ / R, with an angle of α3 and a height aligned with the cross-section of the rotor bracket access door as much as possible.

[0055] If the counterweight installation angle does not allow for the installation of the counterweight, the counterweight mass must be split into adjacent installable positions.

[0056] The counterweight blocks are manufactured based on the calculated mass. These blocks are typically provided by the manufacturer and require only weighing and simple cutting at the power plant site (bolts, locking plates, and weld metal should be included in the counterweight mass). The manufactured counterweight blocks are installed on the rotor yoke at the calculated angle and height, and secured according to the drawing.

[0057] After the unit is started, the runout data is checked using dedicated measuring equipment or unit status monitoring equipment to verify whether it meets the contract requirements. Verification has shown that the rotor assembled using the present method does not require additional counterweights during the dynamic balancing test phase. After assembly and unit startup, the runout data meets the contract requirements.

Claims

1. A method for dynamic balancing of a vertical hydro-generator set with zero counterweight, characterized in that: The method comprises the following steps: S1. During the rotor assembly stage, the rotor assembly quality eccentricity control is performed to control the rotor imbalance caused by assembly to a negligible range; S2. Calculate the rotor imbalance caused by the asymmetric structure on the rotor; the asymmetric structure on the rotor includes the rotor lead assembly and the rotor bracket entry hole; calculate the imbalance caused by the rotor lead assembly and the rotor bracket entry hole separately; calculate the imbalance caused by the rotor lead assembly and the rotor bracket entry hole separately according to the formula U=│Gr│∠α, where G represents the unbalanced mass, that is, the mass of the rotor lead assembly and the rotor bracket entry hole; r is the radius where the unbalanced mass exists, that is, the radius of the center of gravity of the rotor lead assembly and the rotor bracket entry hole; α is the circumferential reference angle, which is the angle between the unbalanced mass and the +X axis; divide the rotor lead assembly into arc segment lead assembly and straight segment lead assembly, and calculate the unbalance caused by the rotor lead assembly and the rotor bracket entry hole according to the formula U X =│Gr│cosα and U Y =│Gr│sinα The lead and clip assembly unbalance vectors of the arc segment lead assembly are decomposed into the X and Y coordinate axes respectively, and the arc segment lead assembly unbalance amount U1=│U1│∠α1 is obtained by vector synthesis; the straight segment lead assembly unbalance amount U2=│U2│∠α2 is calculated in the same way; S3. Formulate a rotor balancing plan based on the rotor imbalance calculated in step S2. Formulating the rotor balancing plan specifically includes installing the rotor balancing weight on the keyway of the tangential key on the inner wall of the rotor yoke, calculating the mass M1 of the balancing weight required for the arc segment lead assembly according to the formula M1=│U1│ / R, where R is the balancing weight installation radius, U1 represents the imbalance of the arc segment lead assembly, the balancing weight installation angle is α1+180°, and the balancing weight installation height is in the same cross section as the arc segment lead assembly; The same method is used to calculate the mass M2 of the counterweight required for the straight lead assembly, with an angle of α2+180° and a height at the same cross section as the straight lead assembly; If there is a rotor bracket entry hole on the rotor, the mass M3 of the counterweight required for the rotor bracket entry hole is calculated according to the formula M3=│U3│ / R, where U3 represents the imbalance caused by the rotor bracket entry hole, the angle α3, and the height are in the same cross section as the rotor bracket entry hole; S4. Implementing the rotor weight balancing scheme developed in step S3 on the rotor; S5. After the rotor is assembled with counterweights, the counterweight effect of the rotor is verified.

2. A method for dynamic balancing of a vertical hydro-generator set with zero counterweight according to claim 1, characterized in that: In step S1, the rotor assembly mass eccentricity control specifically includes: Yoke stacking eccentricity control, yoke stacking mass eccentricity control and pole hanging mass eccentricity control.

3. A method for dynamic balancing of a vertical hydro-generator set with zero counterweight according to claim 2, characterized in that: The yoke stacking eccentricity control specifically refers to raising the yoke eccentricity standard to ≯0.1mm to reduce the rotor imbalance caused by the yoke eccentricity.

4. A method for dynamic balancing of a vertical hydro-generator set with zero counterweight according to claim 2, characterized in that: The yoke stacking mass eccentricity control specifically refers to subdividing the yoke punching weighing classification gradient into 0.2Kg, and controlling the mass deviation of each layer of yoke punching within 0.2Kg, so as to control the overall mass eccentricity of the yoke after stacking, thereby reducing the rotor imbalance caused by the yoke stacking mass eccentricity.

5. A method for dynamic balancing of a vertical hydro-generator set with zero counterweight according to claim 2, characterized in that: The pole mounting mass eccentricity control specifically refers to increasing the mass deviation standard of the two poles mounted in the symmetrical direction to ≯1Kg when the poles are mounted; when the current pole weight cannot meet the mass deviation standard requirement, vector synthesis counterweight is used to reduce the rotor imbalance caused by the pole mounting mass eccentricity.

6. A method for dynamic balancing of a vertical hydro-generator set with zero counterweight according to claim 1, characterized in that: In the rotor counterweight solution formulated in step S3, the counterweight block installation angle cannot be used to install the counterweight block, and the counterweight mass is decomposed into adjacent installable positions.

Images