Hydro-generator rotor dynamic stress test device

Abstract

The utility model discloses a testing device for a dynamic stress test of a hydro-generator rotor. The testing device consists of a base panel, a supporting plate, a welding seam and a bolt fastening hole, the utility model has the advantages that the test device is simple in structure, convenient to mount and dismount, safe and reliable in fixation, strong in operability and low in coefficient of influence on the unbalance of the overall mass of the rotor. The rotor dynamic stress test device can be applied to rotor dynamic stress tests of water-turbine generator sets with medium and high rotating speeds.

Description

Technical Field

[0001] The utility model relates to the field of test of a hydro-generator set, in particular to a test device for dynamic stress test of a hydro-generator rotor. Background Art

[0002] The research on dynamic stress testing technology of rotors of hydro-turbine generator sets is an important part of the research on key technologies for safety assurance of hydropower projects, and is of great significance for analyzing and solving the safe and stable operation of units.

[0003] The measurement of stress and its status assessment are important means to analyze cracks in the main components of the unit, and can provide key technical guidance for the inspection and maintenance of the hydro-turbine generator set. Since the rotor of the generator is in a rotating state and has a high temperature when the hydro-turbine generator set is running, it brings great difficulties to the test of the dynamic stress of the hydro-turbine generator rotor. The main difficulties are manifested in the following aspects: 1. The anti-interference problem of the output signal of the strain gauge; 2. The problem of temperature compensation of the rotor strain gauge; 3. The problem of determining the measurement point position of the rotor dynamic stress; 4. The problem of fixed protection of the strain gauge and the test device.

[0004] At present, due to the lack of testing methods for the dynamic stress of the rotor of the hydro-turbine generator set, the actual stress condition of the rotor cannot be analyzed, and thus the cause of the rotor crack cannot be accurately determined. Therefore, it is necessary to combine the existing dynamic stress testing technology and testing equipment to study the dynamic stress testing method of the rotating parts of the hydro-turbine unit, and effectively apply it to the dynamic stress test of the rotor bracket of the actual power plant, analyze the cause of the crack, and provide a basis for further in-depth research on the safe and stable operation of the turbine. Utility Model Content

[0005] The purpose of the utility model is to provide a test device for dynamic stress test of a hydro-turbine generator rotor. The technical scheme is as follows: the device is composed of a base panel, a support plate, a weld and bolt engaging holes. The base panel and the support plate are connected by welding. A weld is formed on both sides of the junction of the base panel and the support plate. Four bolt engaging holes are evenly machined on both sides of the base panel along the direction of the weld.

[0006] In the above-mentioned test device for dynamic stress of the turbine generator rotor, the welds on both sides of the joints between the base panel and the support plate are bevel welds.

[0007] Compared with the prior art, the utility model has the following beneficial effects: it can be used for rotor dynamic stress test of medium and large capacity units and medium and high speed pumped storage units, the test device has a simple structure, is easy to install and disassemble, is safe and reliable when fixed, and has strong operability. The weight of the device itself has a low influence coefficient on the overall imbalance of the rotor, and there is no need to consider the influence of the device on the dynamic balance of the rotor. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 The figure is a front view of a hydro-generator rotor dynamic stress test device.

[0009] Figure 2 The figure is a top view of a hydro-generator rotor dynamic stress test device.

[0010] Figure 3 The figure is a side view of a test device for a hydro-generator rotor dynamic stress test.

[0011] Marking instructions in the figure: 1-base panel, 2-support plate, 3-weld, 4-bolt hole. DETAILED DESCRIPTION

[0012] The utility model is further described below in conjunction with the accompanying drawings and specific implementation methods.

[0013] like Figure 1 , Figure 2 , Figure 3 As shown, a test device for dynamic stress test of a hydro-turbine generator rotor is composed of a base panel 1, a support plate 2, a weld 3 and bolt engaging holes 4. The base panel 1 and the support plate 2 are connected by welding. At the junction of the base panel 1 and the support plate 2, a bevel weld 3 is formed on both sides. Four bolt engaging holes 4 are evenly machined on both sides of the base panel 1 along the direction of the weld 3.

[0014] Working principle: The dynamic stress of the rotor of the hydro-turbine generator set is mainly caused by the periodic load generated by the axial force of the rotor, which leads to alternating loads when the rotor rotates at high speed, resulting in stress concentration. The most important stress concentration site that usually causes cracks to occur and expand is the defects of the rotor material, such as slag inclusions and other non-metallic inclusions. Stress concentration also often occurs at the transition fillet of the rotor, and all parts fastened to the rotor form a potential stress concentration area on the fastening surface. For example: due to poor assembly, the gap between the magnetic pole, the magnetic yoke and the positioning shoulder of the rotor center body will produce a concentrated stress effect similar to a groove. When the rotor rotates, the corresponding assembly part may become loose and become a crack excitation source; the generator rotor is very prone to groove-type stress concentration effects. Under the joint action of loose windings or insulating gaskets, the slot wedge becomes a potential crack excitation source.

[0015] In addition, another important reason for the dynamic stress of the turbine generator rotor is the alternating stress formed by vibration. Generally speaking, there are two types of alternating stress on the rotor: 1. Transverse vibration. The bending deformation caused by transverse vibration causes stress in the rotor. There are two types of stress at this time: one is non-alternating and the other is alternating. Fundamental frequency vibration only produces non-alternating stress, while vibrations of other frequencies will produce alternating stress; 2. Torsional vibration. During normal operation, the rotor of the rotating machinery produces stable torsional stress, but in a fault state (load shedding, short circuit, asynchronous grid connection, etc.), the rotor will produce alternating torque, resulting in alternating shear stress.

[0016] Finally, the protection scope of the present invention is not limited to the above-mentioned embodiments. Obviously, those skilled in the art can make various modifications and variations to the present invention without departing from the scope and spirit of the present invention. If these modifications and variations fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications.

Claims

1. A hydro-generator rotor dynamic stress test device, characterized in that: The base panel (1) is composed of a base panel (1), a support plate (2), a weld (3) and bolt engaging holes (4). The base panel (1) and the support plate (2) are connected by welding. A weld (3) is formed on both sides of the junction between the base panel (1) and the support plate (2). Four bolt engaging holes (4) are evenly machined on both sides of the base panel (1) along the direction of the weld (3).

2. A hydro-generator rotor dynamic stress test device according to claim 1, characterized in that: The welds (3) on both sides of the joint between the base panel (1) and the support plate (2) are bevel welds.

Images