Water-turbine generator set rotor dynamic balance detection and counterweight method based on air gap monitoring

Abstract

The invention discloses a water-turbine generator set rotor dynamic balance detection and weight balancing method based on air gap monitoring. The method comprises the steps that air gap values of all magnetic poles on a rotor of a water-turbine generator set under the idle working condition are collected through a plurality of air gap sensors; calculating the air gap of each magnetic pole on the rotor, the average air gap deviation vector sum and the orientation; collecting the air gap value of each magnetic pole on the rotor of the water-turbine generator set under the working condition of 50% rated rotating speed through a plurality of air gap sensors; calculating the deviation vector sum of the air gap and the average air gap of each magnetic pole and the orientation; determining the rotor dynamic balance overweight angle orientation based on a given condition, and determining the orientation meeting the given condition as the rotor dynamic balance overweight angle orientation; and when the deviation between the multiple rotor dynamic balance overweight angle orientations is smaller than a preset threshold value, the counterweight orientation is determined according to one of the rotor dynamic balance overweight angle orientations. Whether the hydroelectric generating set has the rotor dynamic balance problem or not can be rapidly and accurately detected, and the balance weight mass and the direction are given.

Description

Technical Field

[0001] The present invention relates to the technical field of water turbine generator fault detection, and particularly to a rotor dynamic balance detection and counterweight method for a water turbine generator set based on air gap monitoring. Background Art

[0002] The generator rotor is a core component of a water turbine generator set and is one of the key components for completing energy conversion. The quality of its performance directly affects the power generation efficiency and safe and stable operation of the entire unit. As a core component, the imbalance of the rotor mass is crucial for the stable operation of the unit. The unbalanced force will cause abnormal vibration problems of the unit, affecting the safe, efficient, and stable operation of the unit, and may even cause safety accidents in severe cases. Therefore, it is particularly important to detect the imbalance of the unit rotor mass.

[0003] The reasons for the rotor dynamic balance are various, such as uneven rotor material, errors generated during processing and assembly, uneven pole deformation, etc. When the rotor rotates, the asymmetric mass distribution causes asymmetric centrifugal force, resulting in adverse effects such as abnormal vibration.

[0004] This centrifugal force obeys the following relationship:

[0005] F l = mω 2 e

[0006] In the formula, F l is the centrifugal force, m is the unbalanced mass, ω is the rotational angular velocity, e is the eccentricity of the unbalanced mass.

[0007] Therefore, the mechanical unbalanced force simply caused by the asymmetric mass distribution is proportional to the square of the rotational speed frequency and is linearly related to the unbalanced mass and the position radius of the unbalanced mass.

[0008] For the dynamic balance problem, after the installation and maintenance of the unit, it is necessary to artificially determine the position and size on a certain plane of the rotor, and then add or subtract some mass for balancing to offset the influence caused by the original unbalanced force. However, currently, the dynamic balance caused by uneven rotor material or manufacturing defects is becoming less and less. Now, the dynamic balance is often caused by uneven pole deformation due to inconsistent pole tightening during the assembly process. This phenomenon is becoming more and more obvious with the large-scale production of pumped storage power stations and the extensive use of high-speed units. Therefore, there is an urgent need to provide a method that can accurately detect the rotor dynamic balance of a water turbine generator set and achieve counterweight. Summary of the Invention

[0009] An object of the present invention is to solve at least the above problems and / or defects and provide at least the advantages described later.

[0010] An object of the present invention is to provide a method for detecting and counterweighting the rotor dynamic balance of a hydro-generator set based on air-gap monitoring, which can quickly and accurately detect whether there is a rotor dynamic balance problem in the hydro-generator set and give the counterweight orientation, without the need to install and arrange test equipment, saving the working cost.

[0011] To achieve these objects and other advantages of the present invention, there is provided a method for detecting and counterweighting the rotor dynamic balance of a hydro-generator set based on air-gap monitoring, including:

[0012] Step 1: Arrange a plurality of air-gap sensors on the stator of the hydro-generator set, divide the plurality of air-gap sensors into two groups, and arrange them on the upper end face and the lower end face of the stator respectively. Each group of air-gap sensors includes several air-gap sensors evenly distributed in the circumferential direction relative to the rotor. The two groups of air-gap sensors correspond one by one, and the two corresponding air-gap sensors are located in the same orientation of the stator;

[0013] Step 2: Collect the air-gap clearance values of each magnetic pole on the rotor of the hydro-generator set under the no-load condition through the plurality of air-gap sensors;

[0014] Step 3: According to the air-gap clearance values of each magnetic pole on the rotor of the hydro-generator set under the no-load condition collected by each air-gap sensor, calculate the sum of the deviation vectors of the air-gap of each magnetic pole on the rotor of the hydro-generator set under the no-load condition corresponding to each air-gap sensor from the average air-gap and the orientation of the sum of the deviation vectors of the air-gap from the average air-gap;

[0015] Step 4: Collect the air-gap clearance values of each magnetic pole on the rotor of the hydro-generator set under the 50% rated speed condition through the plurality of air-gap sensors;

[0016] Step 5: According to the air-gap clearance values of each magnetic pole on the rotor of the hydro-generator set under the 50% rated speed condition collected by each air-gap sensor, calculate the sum of the deviation vectors of the air-gap of each magnetic pole on the rotor of the hydro-generator set under the 50% rated speed condition corresponding to each air-gap sensor from the average air-gap and the orientation of the sum of the deviation vectors of the air-gap from the average air-gap;

[0017] Step 6. Based on the given conditions, determine the overweight angle orientation of the rotor dynamic balance corresponding to each air-gap sensor according to the sum of the air-gap and average air-gap deviation vectors of each magnetic pole on the rotor and the orientation of the sum of the air-gap and average air-gap deviation vectors under the no-load condition and 50% rated speed condition of the hydro-generator set. The given conditions include: when the sum of the air-gap and average air-gap deviation vectors of each magnetic pole on the rotor collected by the same air-gap sensor under the no-load condition of the hydro-generator set is greater than or equal to 4% of the average air-gap value, and when the deviation between the orientation of the sum of the air-gap and average air-gap deviation vectors of each magnetic pole on the rotor collected by the same air-gap sensor under the no-load condition of the hydro-generator set and the orientation of the sum of the air-gap and average air-gap deviation vectors of each magnetic pole on the rotor collected by the same air-gap sensor under the 50% rated speed condition of the hydro-generator set is less than or equal to 30°, it is determined that counterweight is required, and the orientation of the sum of the air-gap and average air-gap deviation vectors of each magnetic pole on the rotor that meets the given conditions is determined as the overweight angle orientation of the rotor dynamic balance;

[0018] Step 7. Verify the overweight angle orientations of the rotor dynamic balance corresponding to the two groups of air-gap sensors respectively. When the deviation between the overweight angle orientations of the rotor dynamic balance corresponding to each group of air-gap sensors is less than a preset threshold, determine the counterweight orientation according to one of the overweight angle orientations of the rotor dynamic balance corresponding to each group of air-gap sensors;

[0019] Step 8. Determine the counterweight weight in the counterweight orientation.

[0020] Preferably, in the method for detecting and counterweighting the rotor dynamic balance of a hydro-generator set based on air-gap monitoring, when the rotor diameter is less than or equal to 7.5 m, each group of air-gap sensors includes 4 air-gap sensors; when the rotor diameter is greater than 7.5 m, each group of air-gap sensors includes 8 air-gap sensors.

[0021] Preferably, in the method for detecting and counterweighting the rotor dynamic balance of a hydro-generator set based on air-gap monitoring, in Step 6, the given conditions include: when the sum of the air-gap and average air-gap deviation vectors of each magnetic pole on the rotor collected by the same air-gap sensor under the no-load condition of the hydro-generator set is between 3% and 4% of the average air-gap value, and when the deviation between the orientation of the sum of the air-gap and average air-gap deviation vectors of each magnetic pole on the rotor collected by the same air-gap sensor under the no-load condition of the hydro-generator set and the orientation of the sum of the air-gap and average air-gap deviation vectors of each magnetic pole on the rotor measured by the same air-gap sensor under the 50% rated speed condition of the hydro-generator set is less than or equal to 30°, it is determined that counterweight is necessary, and the orientation of the sum of the air-gap and average air-gap deviation vectors of each magnetic pole on the rotor that meets the given conditions is determined as the overweight angle orientation of the rotor dynamic balance.

[0022] Preferably, in the rotor dynamic balance detection and counterweight method of the hydro-generator unit based on air-gap monitoring, in step seven, when the deviation between the rotor dynamic balance overweight angle azimuths corresponding to any one of a group of air-gap sensors on the same end face among multiple air-gap sensors is greater than the preset threshold, the rotor dynamic balance overweight angle azimuth corresponding to the corresponding air-gap sensor is removed.

[0023] Preferably, in the rotor dynamic balance detection and counterweight method of the hydro-generator unit based on air-gap monitoring, in step seven, determining the counterweight azimuth according to one of the rotor dynamic balance overweight angle azimuths corresponding to each group of air-gap sensors includes: setting the azimuth on the opposite side of the rotor corresponding to each group of air-gap sensors at the one rotor dynamic balance overweight angle azimuth as the counterweight azimuth.

[0024] Preferably, in the rotor dynamic balance detection and counterweight method of the hydro-generator unit based on air-gap monitoring, in step eight, determining the counterweight weight at the counterweight azimuth includes: determining the counterweight weight at the counterweight azimuth according to the trial weight empirical formula.

[0025] Preferably, in the rotor dynamic balance detection and counterweight method of the hydro-generator unit based on air-gap monitoring, in step eight, determining the counterweight weight at the counterweight azimuth includes: performing counterweight at the counterweight azimuth by the method of adding torque.

[0026] The present invention has at least the following beneficial effects:

[0027] The present invention provides a method for detecting the dynamic balance and counterweight of a hydro-generator rotor based on air-gap monitoring, including: Step 1, arranging a plurality of air-gap sensors on the stator of the hydro-generator, dividing the plurality of air-gap sensors into two groups, respectively arranging them on the upper end face and the lower end face of the stator, each group of air-gap sensors including several air-gap sensors evenly distributed in the circumferential direction relative to the rotor, the two groups of air-gap sensors corresponding one by one, and the two corresponding air-gap sensors being located in the same azimuth of the stator; Step 2, collecting the air-gap clearance values of each magnetic pole on the rotor of the hydro-generator under the no-load operating condition through the plurality of air-gap sensors; Step 3, calculating the sum of the deviation vectors between the air-gap of each magnetic pole on the rotor of the hydro-generator under the no-load operating condition and the average air-gap corresponding to each air-gap sensor, and the azimuth of the sum of the deviation vectors between the air-gap and the average air-gap; Step 4, collecting the air-gap clearance values of each magnetic pole on the rotor of the hydro-generator under the 50% rated speed operating condition through the plurality of air-gap sensors; Step 5, calculating the sum of the deviation vectors between the air-gap of each magnetic pole on the rotor of the hydro-generator under the 50% rated speed operating condition and the average air-gap corresponding to each air-gap sensor, and the azimuth of the sum of the deviation vectors between the air-gap and the average air-gap; Step 6, based on the given conditions, determining the overweight angle azimuth of the rotor dynamic balance corresponding to each air-gap sensor according to the sum of the deviation vectors between the air-gap of each magnetic pole on the rotor of the hydro-generator under the no-load operating condition and the average air-gap, and the azimuth of the sum of the deviation vectors between the air-gap and the average air-gap corresponding to each air-gap sensor. The given conditions include: when the sum of the deviation vectors between the air-gap of each magnetic pole on the rotor collected by the same air-gap sensor of the hydro-generator under the no-load operating condition is greater than or equal to 4% of the average air-gap value, and when the deviation between the azimuth of the sum of the deviation vectors between the air-gap of each magnetic pole on the rotor collected by the same air-gap sensor of the hydro-generator under the no-load operating condition and the azimuth of the sum of the deviation vectors between the air-gap of each magnetic pole on the rotor collected by the same air-gap sensor of the hydro-generator under the 50% rated speed operating condition is less than or equal to 30°, it is determined that counterweight is required, and the azimuth of the sum of the deviation vectors between the air-gap of each magnetic pole on the rotor that meets the given conditions and the average air-gap is determined as the overweight angle azimuth of the rotor dynamic balance; Step 7, respectively verifying the overweight angle azimuths of the rotor dynamic balance corresponding to the two groups of air-gap sensors. When the deviation between the overweight angle azimuths of the rotor dynamic balance corresponding to each group of air-gap sensors is less than a preset threshold, determining the counterweight azimuth according to one of the overweight angle azimuths of the rotor dynamic balance corresponding to each group of air-gap sensors; Step 8, determining the counterweight weight at the counterweight azimuth.The present invention can quickly and accurately detect whether there are rotor dynamic balance problems in a hydro-generating unit. By using the single air-gap measurement data of different end faces, the mass and azimuth of the dynamic balance counterweight blocks on different end faces of the rotor of the hydro-generating unit can be calculated, without the need to install and arrange test equipment, saving the working cost.

[0028] Other advantages, objectives and features of the present invention will be partially reflected by the following description and partially understood by those skilled in the art through the research and practice of the present invention. Brief Description of the Drawings

[0029] Figure 1 It is a flowchart of the method for detecting and counterweighting the rotor dynamic balance of a hydro-generating unit based on air-gap monitoring provided by the present invention. Detailed Embodiment

[0030] The following further describes the present invention in detail with reference to the drawings, so that those skilled in the art can implement it according to the description in the specification.

[0031] As Figure 1 shown, the present invention provides a method for detecting and counterweighting the rotor dynamic balance of a hydro-generating unit based on air-gap monitoring, including:

[0032] Step 1: Arrange air-gap sensors: Arrange a plurality of air-gap sensors on the stator of the hydro-generating unit. Divide the plurality of air-gap sensors into two groups, and arrange them on the upper end face and the lower end face of the stator respectively. Each group of air-gap sensors includes several air-gap sensors evenly distributed circumferentially relative to the rotor. The two groups of air-gap sensors correspond one by one, and the two corresponding air-gap sensors are located in the same azimuth of the stator;

[0033] Step 2: Collect air-gap data under the no-load condition of the unit: Collect the air-gap clearance values of each magnetic pole on the rotor of the hydro-generating unit under the no-load condition through the plurality of air-gap sensors;

[0034] Step 3: Calculate the vector sum and the azimuth of the deviation between the air-gap and the average air-gap under the no-load condition of the unit: According to the air-gap clearance values of each magnetic pole on the rotor of the hydro-generating unit collected by each air-gap sensor, calculate the vector sum of the deviation between the air-gap and the average air-gap of the rotor of the hydro-generating unit corresponding to each air-gap sensor under the no-load condition and the azimuth of the vector sum of the deviation between the air-gap and the average air-gap;

[0035] Step 4: Collect air-gap data under the 50% rated speed condition of the unit: Collect the air-gap clearance values of each magnetic pole on the rotor of the hydro-generating unit under the 50% rated speed condition through the plurality of air-gap sensors;

[0036] Step Five: Sum Vector and Location of the Deviation between Air Gap and Average Air Gap under 50% Rated Speed Condition of the Computer Set: Based on the air gap clearance values of each magnetic pole on the rotor of the hydro-generator set under 50% rated speed condition collected by each air gap sensor, calculate the sum vector of the deviation between the air gap and the average air gap of each magnetic pole on the rotor of the hydro-generator set corresponding to each air gap sensor under 50% rated speed condition, and the location of the sum vector of the deviation between the air gap and the average air gap.

[0037] Step Six: Determine the Overweight Angle Location of the Rotor Dynamic Balance Corresponding to Each Air Gap Sensor Based on Given Conditions: Based on the sum vector of the deviation between the air gap and the average air gap of each magnetic pole on the rotor and the location of the sum vector of the deviation between the air gap and the average air gap under no-load condition and 50% rated speed condition of the hydro-generator set corresponding to each air gap sensor, determine the overweight angle location of the rotor dynamic balance corresponding to each air gap sensor based on given conditions. The given conditions include: when the sum vector of the deviation between the air gap and the average air gap of each magnetic pole on the rotor collected by the same air gap sensor under no-load condition of the hydro-generator set is greater than or equal to 4% of the average air gap value, and when the deviation between the location of the sum vector of the deviation between the air gap and the average air gap of each magnetic pole on the rotor collected by the same air gap sensor under no-load condition of the hydro-generator set and the location of the sum vector of the deviation between the air gap and the average air gap of each magnetic pole on the rotor collected by the same air gap sensor under 50% rated speed condition of the hydro-generator set is less than or equal to 30°, it is determined that counterweight is required, and the location of the sum vector of the deviation between the air gap and the average air gap of each magnetic pole on the rotor that meets the given conditions is determined as the overweight angle location of the rotor dynamic balance.

[0038] Step Seven: Verify and Determine the Overweight Angle Location of the Rotor Dynamic Balance: Verify the overweight angle location of the rotor dynamic balance corresponding to the two groups of air gap sensors respectively. When the deviation between the overweight angle locations of the rotor dynamic balance corresponding to each group of air gap sensors is less than a preset threshold, determine the counterweight location according to one of the overweight angle locations of the rotor dynamic balance corresponding to each group of air gap sensors.

[0039] Step Eight: Determine the Counterweight Weight at the Counterweight Location.

[0040] For the dynamic balance detection and counterweight method of the hydro-generator set based on air gap monitoring described in the present invention, it is prerequisite to default that there are no defects in the design process of the unit and there are no obvious asymmetries in the rotor design or processing.

[0041] Based on the signals of the air-gap monitoring system installed on the hydro-generator unit, this method obtains the air-gap clearance values and average air-gap of each pole under the no-load condition, and then calculates the sum of the deviation vectors of the air-gap of each pole from the average air-gap or the sum of the air-gap vectors of each pole to obtain the deviation and orientation of the rotor centroid. Then, it obtains the air-gap clearance values and average air-gap of each pole under the 50% rated speed condition, and then calculates the sum of the deviation vectors of the air-gap of each pole from the average air-gap or the sum of the air-gap vectors of each pole to obtain the deviation and orientation of the rotor centroid at this speed. Combining with the requirements of the national standard GBT8564, under the no-load condition, the deviation of the rotor centroid is judged by taking whether the centroid deviation exceeds 4% of the average air-gap value as the threshold, and at the same time, the change amount of the centroid deviation orientation under the 50% rated speed and no-load conditions is judged by taking the angle deviation less than 30° (the allowable angle deviation is smaller at higher speeds) as the threshold, so as to determine whether the unit needs to be counterweighted. At the same time, the calculation results of the air-gap sensors in different orientations are compared and verified, and combined with the empirical formula of the trial weight, the dynamic balance detection and counterweight of the unit rotor are realized, and the mass and orientation of the counterweight block are given. To sum up, this method can directly detect by obtaining the data of a single air-gap sensor and verify with multi-sensor data without installing and arranging test equipment, and can quickly and accurately detect whether there is a rotor dynamic balance problem in the unit and give the counterweight orientation, which can effectively improve the accuracy of dynamic balance counterweight to a certain extent and save the working cost. This method is also applicable to both rigid and elastic thrust support units and is easy to popularize and apply.

[0042] In a preferred embodiment, in the method for detecting and counterweighting the dynamic balance of the hydro-generator unit rotor based on air-gap monitoring, when the rotor diameter is less than or equal to 7.5 m, each group of air-gap sensors includes 4 air-gap sensors; when the rotor diameter is greater than 7.5 m, each group of air-gap sensors includes 8 air-gap sensors.

[0043] In a preferred embodiment, in the method for detecting and counterweighting the dynamic balance of the hydro-generator unit rotor based on air-gap monitoring, in step six, the given conditions include: when the sum of the deviation vectors of the air-gap of each pole on the rotor collected by the same air-gap sensor under the no-load condition of the hydro-generator unit is between 3% and 4% of the average air-gap value, and when the deviation between the orientation of the sum of the deviation vectors of the air-gap of each pole on the rotor collected by the same air-gap sensor under the no-load condition of the hydro-generator unit and the orientation of the sum of the deviation vectors of the air-gap of each pole on the rotor measured by the same air-gap sensor under the 50% rated speed condition of the hydro-generator unit is less than or equal to 30°, it is determined that counterweighting is necessary, and the orientation of the sum of the deviation vectors of the air-gap of each pole on the rotor that meets the given conditions is determined as the overweight angle orientation of the rotor dynamic balance.

[0044] In a preferred embodiment, in the method for detecting the dynamic balance and adding counterweights of the rotor of a hydro-generator set based on air-gap monitoring, in step 7, when the deviation between the dynamic balance overweight angular positions of the rotor corresponding to any one of a group of air-gap sensors on the same end face among multiple air-gap sensors is greater than the preset threshold, the dynamic balance overweight angular position corresponding to the corresponding air-gap sensor is removed.

[0045] In a preferred embodiment, in the method for detecting the dynamic balance and adding counterweights of the rotor of a hydro-generator set based on air-gap monitoring, in step 7, determining the counterweight position according to one of the dynamic balance overweight angular positions corresponding to each group of air-gap sensors includes: setting the position on the rotor corresponding to each group of air-gap sensors, which is on the opposite side of the one dynamic balance overweight angular position, as the counterweight position.

[0046] In a preferred embodiment, in the method for detecting the dynamic balance and adding counterweights of the rotor of a hydro-generator set based on air-gap monitoring, in step 8, determining the counterweight weight at the counterweight position includes: determining the counterweight weight at the counterweight position according to the empirical formula for trial weight.

[0047] In a preferred embodiment, in the method for detecting the dynamic balance and adding counterweights of the rotor of a hydro-generator set based on air-gap monitoring, in step 8, determining the counterweight weight at the counterweight position includes: adding counterweights at the counterweight position by applying torque.

[0048] The specific steps of this method are described in detail below.

[0049] Step (1): Define the polar coordinate system of the rotor, stipulate that the position of the key-phase block of the unit is 0°, and the counterclockwise direction is the positive angle.

[0050] Step (2): Number the rotor magnetic poles, stipulate that the position corresponding to the key-phase block of the unit is the No. 1 magnetic pole, and number them in sequence in the clockwise direction, and so on, with a total of N magnetic poles.

[0051] Step (3): Set the number and positions of the system air-gap sensors. Taking the installation of 4 sensors on the upper and lower end faces of the stator as an example, they are evenly arranged along the circumference at +X, +Y, -X, -Y. The number of air-gap sensors for monitoring the air gap of a hydro-generator can be configured according to the structural parameters of the generator in a hydropower plant. Generally, when the rotor diameter is less than 7.5 m, it is recommended to configure 4 sensors for each end face, and when it is greater than 7.5 m, it is recommended to configure 8 sensors for each end face. The measuring points are evenly distributed along the circumferential direction. For example, when arranging 4 measuring points, they are usually arranged at the +X, +Y, -X, -Y positions.

[0052] Step (4): Collect and obtain the air-gap data A of each pole of the unit under no-load condition (100% rated speed) through the air-gap monitoring system. t0 (n), where A t0 (n) is the nth pole air-gap value under no-load condition, and n = 1 - N.

[0053] Step (5): For the air-gap data of each pole of the unit collected by any air-gap sensor under no-load condition, calculate the sum of deviation vectors of the air-gap of each pole from the average air-gap and the azimuth θ and the azimuth θ t0_sum .

[0054] a. Calculate and obtain the vector value and coordinate components of the air-gap of each pole of the unit under no-load condition.

[0055]

[0056]

[0057] Where: is the vector value of the air-gap of each pole under no-load condition;

[0058] is the X component of the vector coordinate of the air-gap of each pole under no-load condition;

[0059] is the Y component of the vector coordinate of the air-gap of each pole under no-load condition;

[0060] θ t0 (n ) is the azimuth angle of the air-gap of each pole under no-load condition.

[0061] b. Calculate and obtain the average air-gap A of each pole of the unit under no-load condition, t0_Avg the sum of deviation vectors of the air-gap of each pole from the average air-gap, and the azimuth θ t0_sum ;

[0062]

[0063] Where: A t0_Avg is the average air-gap of each pole under no-load condition;

[0064] is the average air-gap vector in the corresponding direction of each pole under no-load condition;

[0065] is the sum of deviation vectors of the air-gap of each pole from the average air-gap under no-load condition;

[0066] θ t0_sumIt is the azimuth of the vector sum of the air-gap deviations of each magnetic pole from the average air-gap under the no-load condition. Note that when it is in the first quadrant, the azimuth angle is θ t1_sum ; when it is in the second and third quadrants, the azimuth angle is θ t1_sum + 180°; when it is in the fourth quadrant, the azimuth angle is -(θ t1_sum ) + 360°.

[0067] Step (6) collects and obtains the air-gap clearance values A t1 (n) of each magnetic pole of the unit under the 50% rated speed condition, where A t1 (n) is the air-gap clearance value of the nth magnetic pole under the 50% rated speed condition, and n = 1 to N.

[0068] Step (7) uses the same method as in step (5) to calculate and obtain the vector sum of the air-gap deviations of each magnetic pole of the unit from the average air-gap and the azimuth θ t1_sum .

[0069] a. Calculate and obtain the air-gap clearance vector values and coordinate components of each magnetic pole of the unit under the 50% rated speed condition

[0070]

[0071]

[0072] Among them: is the air-gap clearance vector value of each magnetic pole under the 50% rated speed condition;

[0073] is the X component of the air-gap clearance vector coordinate of each magnetic pole under the 50% rated speed condition;

[0074] is the Y component of the air-gap clearance vector coordinate of each magnetic pole under the 50% rated speed condition;

[0075] θ t1 (n) is the azimuth angle of the air-gap clearance of each magnetic pole under the 50% rated speed condition.

[0076] b. Calculate and obtain the average air-gap A t1_Avg of each magnetic pole, the vector sum of the air-gap deviations of each magnetic pole from the average air-gap and the azimuth θ t1_sum ;

[0077]

[0078] Among them: A t1_Avg is the average air-gap of each magnetic pole under the 50% rated speed condition;

[0079] is the average air-gap vector value of each magnetic pole under the condition of 50% rated speed;

[0080] is the sum of the deviation vectors of the air-gap of each magnetic pole from the average air-gap under the condition of 50% rated speed;

[0081] θ t1_sum is the azimuth of the sum of the deviation vectors of the air-gap of each magnetic pole from the average air-gap under the condition of 50% rated speed. Note that when it is in the first quadrant, the azimuth angle is θ t1_sum ; when it is in the second and third quadrants, the azimuth angle is θ t1_sum + 180°; when it is in the fourth quadrant, the azimuth angle is -(θ t1_sum ) + 360°.

[0082] Step (8) Compare the sum of the deviation vectors of the air-gap of each magnetic pole from the average air-gap and the azimuth with the given threshold values. The dynamic balance counterweight of the unit needs to satisfy both conditions: Condition 1, when the sum of the deviation vectors of the air-gap of each magnetic pole from the average air-gap is between 3% and 4% of the average air-gap value, it is necessary to add counterweight; when it is greater than or equal to 4% of the average air-gap value, it is necessary to add counterweight; Condition 2, the azimuth deviation Δθ of the sum of the deviation vectors of the air-gap of each magnetic pole from the average air-gap between the 50% rated speed condition and the no-load condition should be less than or equal to 30°. When calculating this Δθ, note that when |θ t0_sum - θ t1_sum | ≤ 180°, the result is Δθ = |θ t0_sum - θ t1_sum |, when |θ t0_sum - θ t1_sum | > 180°, the result is Δθ = 360 - |θ t0_sum - θ t1_sum |.

[0083]

[0084] Δθ ≤ 30° Formula (16)

[0085] If the above threshold requirements are met simultaneously, it can be considered that there is rotor dynamic balance in the unit, and the overweight angle azimuth θ t0_sum .

[0086] Step (9) Obtain the calculation results of the air-gap sensors in different azimuths and verify them. Among them, each air-gap sensor corresponds to a measuring point. For different measuring points on the same end face, the calculated azimuths should deviate by no more than 10°. If there is a measuring point with an obvious deviation in the counterweight azimuth, it means that the calculated value of this measuring point is suspicious and should be removed. Select the measuring points with correct calculation results as the final result to prevent calculation errors caused by sensor installation errors or malfunctions.

[0087] After step (10) is verified without error, the dynamic balance detection and weight addition of the unit rotor are realized by combining the trial weight method, and the mass and azimuth of the weight block are given. The position where the weight block needs to be added is the weight loss angle, that is, the opposite side of the overweight angle φ = θ t0_sum +180°.

[0088] In step (11), the final weight addition is determined according to the empirical formula of the trial weight. The empirical formula of the trial weight is as follows:

[0089]

[0090] In the formula: P—the mass of the trial weight block, kg; G—the mass of the rotor, kg; g—the gravitational acceleration, 9.81 m / s 2 ; R—the fixed radius of the trial weight block, m; n—the rated speed of the unit, r / min.

[0091] The following provides an embodiment for specifically illustrating the method provided by the present invention.

[0092] For a certain hydropower unit, the generator rotor has a total of 28 magnetic poles, the rated speed is 214.286 r / min, the rotor weight is 240 t, the rotor radius is about 3.5 m, and the dynamic balance detection and weight addition of the unit are carried out by using the method of the present invention. The detailed steps are as follows:

[0093] In step (1), the rotor polar coordinate system is defined, and it is stipulated that the position of the unit key phase block is 0°, and the counterclockwise direction is the positive angle;

[0094] In step (2), the magnetic poles of the rotor are numbered. It is stipulated that the position corresponding to the unit key phase block is the No. 1 magnetic pole, and the numbers are sequentially numbered in the clockwise direction, and so on, with a total of N magnetic poles;

[0095] In step (3), the number and position of the system air gap sensors are set. Taking the installation of 4 sensors on the upper and lower parts of the stator as an example, they are evenly arranged along the circumference at +X, +Y, -X, -Y;

[0096] In step (4), the air gap data A t0 (n) of each magnetic pole of the unit under the no-load condition (100% rated speed) are collected and obtained through the air gap monitoring system, and records are made. The data record form is shown in Table 1.

[0097] Table 1

[0098]

[0099]

[0100] In step (5), the air gap clearance values A t1 (n) of each magnetic pole of the unit under the 50% rated speed condition are collected and obtained through the air gap monitoring system, and records are made. The data record form is shown in Table 2.

[0101] Table 2

[0102]

[0103]

[0104] Step (6) a. Calculate and obtain the vector sum and azimuth θ of the deviation of each pole air gap from the average air gap under the no-load and 50% rated speed conditions of the unit and azimuth θ t0_sum 、θ t1_sum ; b. Compare the vector sum of the deviation of each pole air gap from the average air gap and the azimuth deviation of the vector sum of the deviation of each pole air gap from the average air gap under the 50% rated speed condition and the no-load condition with the threshold value respectively, and give the overweight angle azimuth; c. Synchronously calculate and obtain the calculation results of the air gap sensors in different azimuths for verification, make records, and the data record form is shown in Table 3

[0105] Table 3

[0106]

[0107]

[0108] After step (7) is verified, combine the trial weight method and the empirical formula of the trial weight to realize the dynamic balance detection and counterweight of the unit rotor, give the mass and azimuth of the counterweight block, and the position where the counterweight block needs to be added is the weight loss angle, that is, the opposite side of the overweight angle. Make records, and the data record form is shown in Table 4

[0109] Table 4

[0110]

[0111] It can be seen from the calculation results of Tables 3 and 4 that the calculation results of the measurement data of each air gap sensor are basically the same. The unit needs to be counterweighted at about 309° azimuth, that is, rotate 309° counterclockwise from the key phase block position. The mass of the trial weight is about 38KG, and the actual counterweight weight can be taken as about 1.5 times the trial weight according to experience, that is, the weight of the counterweight block is about 57KG, and the on-site counterweight effect is obvious

[0112] In summary, the present invention obtains the air-gap clearance values measured by each air-gap sensor for each magnetic pole under the no-load conditions of the upper and lower end faces of the rotor based on the air-gap monitoring data, and respectively calculates the vector sum of the deviations of the air gaps of each magnetic pole from the average air gap under the no-load conditions of the upper and lower end faces of the unit (it is also possible to directly calculate the vector sum of the air gaps of each magnetic pole, that is, theoretically, the dynamic balance of the rotor is reflected by the unevenness of the magnetic pole deformation of the unit), and compares it with the air-gap deviation threshold specified in the national standard to determine whether there is a rotor dynamic balance problem and its orientation in the unit; at the same time, the calculation results of the air-gap sensors in different orientations on the same end face are compared and verified; combined with the empirical formula of the trial weight, the dynamic balance counterweight of the rotor of the unit is realized, and the mass and orientation of the counterweight block are given. Among them, if the air-gap measurement data at the upper end meets the counterweight requirements, the counterweight is carried out on the upper end face of the rotor according to the calculation results; if the air-gap measurement data at the lower end meets the counterweight requirements, the counterweight is carried out on the lower end face of the rotor according to the calculation results; if both the upper and lower end faces meet the requirements, the counterweight needs to be carried out by applying torque on the upper and lower end faces of the rotor. This method can directly detect by obtaining the data of a single air-gap sensor and verify with multi-sensor data. There is no need to install and arrange test equipment, and it can quickly and accurately detect whether there is a rotor dynamic balance problem in the unit and give the counterweight orientation, which can effectively improve the accuracy of the dynamic balance counterweight to a certain extent and save the working cost. This method is applicable to both rigid and elastic thrust support units and is easy to popularize and apply.

[0113] Although the embodiments of the present invention have been disclosed as above, they are not limited to the applications listed in the specification and embodiments. It can be fully applied to various fields suitable for the present invention. For those familiar with the field, additional modifications can be easily made. Therefore, without departing from the general concept defined by the claims and their equivalent scope, the present invention is not limited to the specific details and the examples shown and described here.

Claims

1. A method for detecting and balancing the rotor of a hydro-turbine generator set based on air gap monitoring, characterized in that: include: Step 1: arranging a plurality of air gap sensors on the stator of the hydro-generator set, dividing the plurality of air gap sensors into two groups, and arranging them on the upper end surface and the lower end surface of the stator respectively, each group of air gap sensors includes a plurality of air gap sensors evenly distributed relative to the circumference of the rotor, and the two groups of air gap sensors correspond one to one, and the two corresponding air gap sensors are located at the same position of the stator; Step 2: collecting the air gap value of each magnetic pole on the rotor of the hydro-generator set under idling condition through the multiple air gap sensors; Step 3, according to the air gap clearance value of each magnetic pole on the rotor of the hydro-generator set under idling condition collected by each air gap sensor, calculate the air gap of each magnetic pole on the rotor of the hydro-generator set corresponding to each air gap sensor under idling condition and the average air gap deviation vector sum and the direction of the air gap and the average air gap deviation vector sum; Step 4: collecting the air gap value of each magnetic pole on the rotor of the hydro-generator set at 50% of the rated speed through the multiple air gap sensors; Step 5, according to the air gap clearance value of each magnetic pole on the rotor of the hydro-generator set under the condition of 50% rated speed collected by each air gap sensor, calculate the air gap deviation vector sum of each magnetic pole on the rotor of the hydro-generator set corresponding to each air gap sensor under the condition of 50% rated speed and the direction of the air gap deviation vector sum; Step 6: According to the air gap deviation vector sum of each magnetic pole on the rotor and the average air gap deviation vector sum under the idling condition and 50% rated speed condition of the hydro-generator set corresponding to each air gap sensor and the azimuth of the air gap deviation vector sum, the rotor dynamic balance overweight angle azimuth corresponding to each air gap sensor is determined based on given conditions, wherein the given conditions include: when the air gap deviation vector sum of each magnetic pole on the rotor and the average air gap deviation vector sum collected by the same air gap sensor of the hydro-generator set under idling condition is greater than or equal to 4% of the average air gap value, and when If the deviation between the sum of the air gaps of the magnetic poles on the rotor and the average air gap deviation vector and the sum of the air gaps of the magnetic poles on the rotor collected by the same air gap sensor under the idling condition of the hydro-generator set and the sum of the air gaps of the magnetic poles on the rotor collected by the same air gap sensor under the condition of 50% of the rated speed of the hydro-generator set is less than or equal to 30°, it is determined that counterweighting is required, and the sum of the air gaps of the magnetic poles on the rotor and the average air gap deviation vector and the sum of the air gaps of the magnetic poles on the rotor that meet the given conditions are determined as the overweight angle azimuth of the dynamic balance of the rotor; Step 7, respectively verifying the rotor dynamic balance overweight angle orientations corresponding to the two groups of air gap sensors, and when the deviation between the rotor dynamic balance overweight angle orientations corresponding to each group of air gap sensors is less than a preset threshold, determining the counterweight orientation according to one of the rotor dynamic balance overweight angle orientations corresponding to each group of air gap sensors; Step eight, determining the weight of the counterweight at the counterweight position.

2. The method for dynamic balancing and weight balancing of a rotor of a hydro-turbine generator set based on air gap monitoring according to claim 1, characterized in that: When the rotor diameter is less than or equal to 7.5 m, each group of air gap sensors includes 4 air gap sensors; when the rotor diameter is greater than 7.5 m, each group of air gap sensors includes 8 air gap sensors.

3. The method for dynamic balancing and weight balancing of a rotor of a hydro-turbine generator set based on air gap monitoring according to claim 1, characterized in that: In the step six, the given conditions include: when the air gap of each magnetic pole on the rotor collected by the same air gap sensor under the idling condition of the hydro-turbine generator set and the average air gap deviation vector sum are between 3% and 4% of the average air gap value, and when the deviation between the air gap of each magnetic pole on the rotor collected by the same air gap sensor under the idling condition and the average air gap deviation vector sum and the air gap of each magnetic pole on the rotor measured by the same air gap sensor under 50% of the rated speed of the hydro-turbine generator set is less than or equal to 30°, it is determined that balancing is necessary, and the air gap of each magnetic pole on the rotor that meets the given conditions and the average air gap deviation vector sum are located The orientation is determined as the rotor dynamic balance overweight angle orientation.

4. The method for dynamic balancing and weight balancing of a hydro-turbine generator rotor based on air gap monitoring according to claim 1, characterized in that: In step seven, when the deviation between the rotor dynamic balance overweight angle orientations corresponding to any one of a group of air gap sensors on the same end face among the multiple air gap sensors is greater than the preset threshold, the rotor dynamic balance overweight angle orientation corresponding to the corresponding air gap sensor is removed.

5. The method for dynamic balancing and weight balancing of a hydro-turbine generator rotor based on air gap monitoring according to claim 1, characterized in that: In the step seven, determining the counterweight orientation according to one of the rotor dynamic balance overweight angle orientations corresponding to each group of air gap sensors includes: setting the orientation on the rotor corresponding to each group of air gap sensors and located on the opposite side of one of the rotor dynamic balance overweight angle orientations as the counterweight orientation.

6. The method for dynamic balancing and weight balancing of a hydro-turbine generator rotor based on air gap monitoring according to claim 1, characterized in that: In the step eight, determining the weight of the counterweight at the counterweight position includes: determining the weight of the counterweight at the counterweight position according to an empirical formula for trial weight.

7. The method for dynamic balancing and weight balancing of a hydro-generator rotor based on air gap monitoring according to claim 1, characterized in that: In the step eight, determining the weight of the counterweight at the counterweight position includes: performing counterweighting at the counterweight position by adding torque.

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