Mechanism research on active power fluctuation caused by steam turbine valve test

Wang, Jiasheng; Ma, Qinfeng; Zhong, Jingliang; Gou, Xiaolong

doi:10.1007/s00202-018-0693-9

Cited by 6 publications

(5 citation statements)

References 16 publications

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“…The information contained by the data set called self-information can be expressed by Equation (1). The definition of information entropy is proposed as the mathematical expectation of self-information as Equation (2).…”

Section: Entropy Theorymentioning

confidence: 99%

“…A steam turbine is a module converting heat energy into mechanical energy, with the principal task to convert the energy from hot steam into rotational energy in operating. 1 Many equipped sensors for monitoring and multistage steam expansion make the steam turbine a complicated system. 2 Therefore, performance monitoring has critically important significances for economic and safety operation.…”

Section: Introductionmentioning

confidence: 99%

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Information entropy theory for steam turbine system monitoring study

Cui

et al. 2020

Engineering Reports

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A steam turbine is one of the components in a power plant. Considered as a strong coupling system, steam turbines may possess correlation information among the operation parameters. In this article, a correlation extraction method based on mutual information theory is proposed for performance monitoring. First, five functions between two variables including linear and nonlinear relationships are tested to validate the proposed method. In the first industrial case study, a sensor fault detection based on the governing stage pressure is conducted on the abnormal fluctuation mutual entropy values calculated by operation data. The results show the proposed method may effectively be used to detect sensor errors and locate the first error sample. Furthermore, uncertainty analysis on the heat rate is studied to sort the importance degree of the relative parameters. The mutual information entropy difference values are then calculated to quantify the sensitivity degree of the operation parameters to the heat rate index. The results in this case study are in accordance with the sequences by the Guide to the Expression of Uncertainty Measurement (GUM) and Monte Carlo (MC) methods. In conclusion, mutual information entropy may hence be used as a new solution for turbine monitoring, combined with information theory.

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Section: Entropy Theorymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Information entropy theory for steam turbine system monitoring study

Cui

et al. 2020

Engineering Reports

View full text Add to dashboard Cite

show abstract

“…During the test, the main steam pressure, the main steam temperature, and the condenser vacuum were kept relatively stable, and the test data are shown in Tables 8 and 9. At the same time, all local flow coefficients were calculated according to Equation (12) and are listed in the rightmost column of Tables 9 and 10. Table 9.…”

Section: Valve Local Flow Coefficient Kmentioning

confidence: 99%

“…The valve flow characteristics of the actual unit are tested, correcting the valve flow function. Optimizing the valve flow characteristics of the unit can reduce forced power oscillation accidents caused by imperfect valve flow characteristics [11,12]. However, during actual operation, valve flow characteristics may change over time, so valve flow function cannot guarantee reliable matching with the actual unit valve flow characteristics.…”

Section: Introductionmentioning

confidence: 99%

Dynamic Performance Assessment of Primary Frequency Modulation for a Power Control System Based on MATLAB

Wang

2018

Processes

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The primary frequency modulation (PFM) performance of a power control system (PCS) is an important factor affecting the security and stability of a power grid. The traditional control method is proportional integral (PI) control. In order to improve its dynamic control performance, a control method based on the combination of internal model control (IMC) and PI is proposed. Using the method of theoretical assessment and system identification, a simple simulated model of the typical PCS is established. According to the principle of system identification and the least square estimation (LSE) algorithm, the mathematical models of a generator and a built-in model are established. According to the four dynamic performance indexes, the main and auxiliary assessment index of the PCS are defined, and the benchmark and the result of the performance assessment are given. According to three different structures, the PFM dynamic performance of the PCS is analyzed separately. According to the dynamic performance assessment index of PFM, the structure of the control system and the influence of different parameters on the performance of the PCS are analyzed under ideal conditions. The appropriate control structure and controller parameters are determined. Secondly, under the non-ideal condition, the influence of the actual valve flow coefficient on the performance of the control system is studied under two different valve control modes. The simulation results show that the internal model combined with PI has better dynamic control performance and stronger robustness than the traditional PI control, and it also has better application prospects for thermal power plants.

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“…Sweeney [9] proposed the hydraulic clamping was caused by the uneven distribution of the hydraulic pressure, and the groove [10] was machined on the valve core to reduce the volume of the valve [11], which affected the lubrication characteristics, improved the clamping problem, but increased the internal leakage. Lisowski, Wang Yongjiu et al [12,13] modified the valve core structure to improve the flow field and flow characteristics, and solved the problems of wear and jam of hydraulic servo motor [14,15]. Those methods could improve the friction characteristics of the liquid film and enhance the response characteristics of the valve, but it had a great impact on the use of the system due to the change of the existing structure or the increase in internal leakage and other new problems.…”

Section: Introductionmentioning

confidence: 99%

Research on The Controllable Interface Response Enhancement of The Textured Pilot Valve

Xu¹,

Zhang²,

Fan³

et al. 2022

Preprint

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Based on the textured controllable interface effect, the dynamic performances of the textured and ordinary pilot valve are analyzed experimentally, and the influence of the textured controllable interface on the response of pilot valve is studied. Results show that when Pin is small, the textured surface shortens the reciprocating time of valve core, increasing the flow rate, and speeds up the piston stroke of oil cylinder. The valve core actions much more stable and sensitivity. Meanwhile, combined with the theoretical calculation, the operation mechanism of texturing the pilot valve is analyzed. It is concluded that the stress of textured valve core sealing surface is greater than that of ordinary one, and the pressure difference gradually decreases with the increase of Pin, and the flow difference is basically the same as the force on the sealing surface. This indicates that the textured surface improves lubrication characteristics, reduces the friction between components. The textured valve makes the velocity changes gently, and enhances the responsiveness and stability of the valve. Those related results provide a new idea for enhancing the response design of the pilot valve.

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Mechanism research on active power fluctuation caused by steam turbine valve test

Cited by 6 publications

References 16 publications

Information entropy theory for steam turbine system monitoring study

Information entropy theory for steam turbine system monitoring study

Dynamic Performance Assessment of Primary Frequency Modulation for a Power Control System Based on MATLAB

Research on The Controllable Interface Response Enhancement of The Textured Pilot Valve

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