GB/T 36043-2018Specification of large-scale steam turbine-generator shafting dynamic characteristics (English PDF)

Foreword

This standard was drafted in accordance with the rules given in GB/T 1.1-2009.

Introduction

With the development of China's power equipment manufacturing industry, in order to further implement the energy policy of energy saving and emission reduction, water saving and environmental protection, and to meet the needs of power plants The multiple needs of households, research and development of various forms of high-power high-parameter turbine generators is a top priority. The shafting is a large steam turbine One of the key parts of the unit, the pros and cons of its dynamic characteristics directly affect the design and operation of the new high-capacity unit.

For the high-power and high-parameter steam turbines, there is an interstitial steam flow excitation effect in the high and medium pressure sections, which affects the stability of the shaft vibration.

The air-cooled steam turbine cooling method, the exhaust pressure and temperature parameters of the exhaust valve change range, frequent fluctuations, affect the shaft Bearing height and shafting vibration stability, etc.; currently the turbine part is connected to a low pressure cylinder or a semi-connected structure, the above impact It will also become more apparent, therefore, the factors considered in the shafting design phase of large turbine generator sets and the design process need to be correspondingly Extensions.

With the increase of the capacity of the unit, the number of rotors also increases accordingly, and the frame-type basic structure supporting the turbo-generator set is also larger.

The coupling of the dynamic characteristics between the shaft of the unit and the turbine foundation is strengthened, and the support requirements for the foundation of the high-power unit are also increasing, so the power The scope of use of the "Power Machine Basic Design Specification" proposed by the design department may be limited. According to our current system, The design of the group and the foundation is performed in two industries. equipment manufacturing and electric power. The power performance of the unit and the foundation may not be sufficient after manufacture and installation.

The problem of matching directly affects the normal operation and long-term safe operation of the unit. After decades of practice in our country, no matter equipment manufacturing The department or the electric power design department all consider it necessary to consider the unit and the foundation as a whole system. Therefore, at the design stage, The unit and the foundation are used as a system to evaluate the vibration characteristics of the shafting system so as to ensure good dynamic characteristics of large units and foundations. match.

With the development of electric power construction, the power grid environment where the unit is located is also becoming more and more complex. High-power generating units will be affected by various electromagnetic excitations.

Therefore, for turbine shafts with larger torsional shear stresses, strength and safety assessments should be incorporated into the shaft under certain special excitation conditions. The dynamic characteristics of the design specification.

In order to enable China's turbine generator shaft design technology to be synchronized to the large-scale unit and the development needs of the international market, Shaft system vibration stability meets the requirements for long-term safe and stable operation of high-power and high-parameter units, based on the state of technology development and related design specifications Write this standard. This standard can be used as a technical guide for the design of dynamic characteristics of large turbine generator shafts, but it is not accepted as a project acceptance. according to. The manufacture, installation, dynamic balance, operation and basic design and construction of the unit shall all meet relevant technical conditions. This standard does not involve the power grid but requires examination Consider the disturbance excitation from the grid.

1 Scope

This standard specifies the design requirements, design items, calculation methods, design criteria, and models for the dynamic characteristics of large turbine generator shaft sets. Simplification, boundary parameter determination, and design flow.

This standard applies to high-power turbo-generators of 300 MW or above rated speed, other capacity or different power station turbines Also refer to use.

2 Normative references

The following documents are indispensable for the application of this document. For dated references, only dated versions apply to this document. For undated references, the latest version (including all amendments) applies to this document.

GB/T 2298 Mechanical Vibration, Shock and Condition Monitoring Vocabulary

3 Terms and definitions

The following terms and definitions as defined in GB/T 2298 apply to this document. For ease of use, the following is a repeated listing of GB/T 2298 Some of the terms and definitions.

4 Design Principles

The basic principles for designing the dynamic characteristics of shafting are.

--- Rationality. relatively reasonable in principle, there is a certain basis for engineering application practice;

--- Partial security. When the actual and theoretical differences are large and difficult to grasp, try to use partial security methods;

--- Practical application. The engineering application is more convenient and it is not easy to make mistakes.

5 Design requirements

5.1 Within the range of possible operating speed, the forced vibration response value of the turbine generator shaft should be controlled in the radial clearance of the moving and static components. Within the enclosure, and as small as possible, ensure that the running clearance of the moving parts is maintained and the dynamic excitation force transmitted from the rotor to the bearings is as small as possible. Shafting The critical speed should avoid a certain range of working speed, and the magnitude of unbalanced response at key assessment points should be less than the permissible value.

5.2 In the operating speed range and under various design operating load conditions, the rotor and the bearing system should not exhibit bearing oil film oscillation or steam shock. Excited self-induced instability vibration.

5.3 The system dynamic characteristics should not be sensitive to manufacturing and installation errors and changes in operating conditions within a certain interval. Rotors, bearings and housings and bases The dynamic characteristics of the foundation are well matched, so that the critical speed of the shafting system is insensitive to changes in the support stiffness; the bearing bearing position is designed in a reasonable manner so that the bearing load Not sensitive to changes in bearing elevation; good bearing damping characteristics, making the system vibration response insensitive to changes in imbalance; large diameter bearings have to have Large bearing range. For air-cooled turbines, the bearing support of the low-pressure rotor should adopt a floor-standing or semi-floored bearing seat.

5.4 Calculate the torsional vibration natural frequency and vibration mode of the unit shaft. Considering that the grid disturbance may cause torsional vibration excitation, the torsional vibration of the shaft The frequency should at least avoid the resonance of the grid line frequency and double-line frequency, that is, the intrinsic torsional frequency and line frequency of the shafting within the operating speed range. And double frequency should have sufficient avoidance rate.

5.5 For the two-phase short-circuit fault condition of the generator terminal, the rotor components are required to include connecting parts, long blades and other elastic branching joints. For structures, etc., sufficient strength should be ensured to resist the torsional shear stress generated by the two-phase short circuit of the machine and other accident conditions.

6 Analysis objects

6.1 Bending Vibration and Stability Analysis of High-power Turbogenerator Shaft Systems, Selecting All Rotors and Shafts of Steam Turbines, Generators, and Exciters Bearings, bearing seats and foundations are the objects of analysis.