Critical stable cross-sectional area of surge tank in hydropower plant with multiple units sharing common hydraulic system

Yang, Xiuwei; Lian, Jijian; Yu, Xiaodong; He, Wei‐Ming

doi:10.1016/j.ijepes.2021.107067

Cited by 11 publications

(4 citation statements)

References 33 publications

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“…For the forced vibration analysis, the RPTs operate in normal conditions and are governed by the regulator. The governing equations of the unit rotational speed are given by 26,27 :

{T}_{a}\frac{d\varphi }{dt}=m-x

where

{T}_{a}=\frac{[G{D}^{2}]{N}_{r}^{2}}{365{P}_{r}}

is the mechanical starting time,

[G{D}^{2}]

is the inertia of rotating fluid and mechanical parts in the turbine and generator,

{N}_{r}

is the rated rotational speed of the unit,

{P}_{r}

is the rated output of the unit;

\varphi =\frac{n-{n}_{0}}{{n}_{0}}

is the dimensionless unit speed,

n

is the rotational speed of the RPT;

m=\frac{m-{m}_{0}}{{m}_{0}}

is the dimensionless output of the RPT; subscript 0 references the initial steady state value.

x

is the load disturbance.…”

Section: Governing Equationsmentioning

confidence: 99%

See 1 more Smart Citation

Forced vibration analysis model for pumped storage power station based on the 1D–3D coupling and pipe walls vibration

Yang

Lian

Wang

et al. 2022

Earthquake Engineering and Resilience

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Hydraulic vibration is a common phenomenon in pumped storage power stations (PSPS) and hydropower plants. Evaluating the performance of the PSPS and water conveyance system under the hydraulic vibration condition is significant for the safety of the electric power and the PSPS system. In this study, the one‐dimensional (1D) and three‐dimensional (3D) coupling model for the entire PSPS system is established based on the open‐source software OpenFOAM and in‐house C++ codes. The coupling data exchange is realized by writing and reading files. The coupling model is validated by comparing the results with the pure 1D method under small load disturbance conditions. The forced vibration source is modeled by the pipe walls vibration method in the 3D region, and the 1D method takes charge of other parts in the PSPS system. The combination of the pipe walls vibration and 1D–3D coupling could fully consider the incident and reflected characteristics of the pressure waves. The established model could evaluate the overall performance of the PSPS system under forced vibration. Sensitive analysis of the vibration magnitude is carried out, and the results are consistent with the theoretical analysis, demonstrating that the established model is applicable for the forced vibration analysis.

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“…For the forced vibration analysis, the RPTs operate in normal conditions and are governed by the regulator. The governing equations of the unit rotational speed are given by 26,27 :

{T}_{a}\frac{d\varphi }{dt}=m-x

where

{T}_{a}=\frac{[G{D}^{2}]{N}_{r}^{2}}{365{P}_{r}}

is the mechanical starting time,

[G{D}^{2}]

is the inertia of rotating fluid and mechanical parts in the turbine and generator,

{N}_{r}

is the rated rotational speed of the unit,

{P}_{r}

is the rated output of the unit;

\varphi =\frac{n-{n}_{0}}{{n}_{0}}

is the dimensionless unit speed,

n

is the rotational speed of the RPT;

m=\frac{m-{m}_{0}}{{m}_{0}}

is the dimensionless output of the RPT; subscript 0 references the initial steady state value.

x

is the load disturbance.…”

Section: Governing Equationsmentioning

confidence: 99%

“…For the forced vibration analysis, the RPTs operate in normal conditions and are governed by the regulator. The governing equations of the unit rotational speed are given by 26,27 :…”

Section: D Mocmentioning

confidence: 99%

Forced vibration analysis model for pumped storage power station based on the 1D–3D coupling and pipe walls vibration

Yang

Lian

Wang

et al. 2022

Earthquake Engineering and Resilience

Self Cite

View full text Add to dashboard Cite

show abstract

“…[29] studied the full operating stability of HTRS under different control modes of governors, which focused on the effect of hydro-turbine nonlinearity on system stability under different operating conditions. [30] focused on the effect of changing operating conditions on hydraulic parameters and studied the effect of unit operating conditions on the critical stable cross-sectional area of surge tank. Regrettably, it didn't consider the role of turbine nonlinearities in different operating conditions.…”

Section: Introductionmentioning

confidence: 99%

Stability analysis of hydropower unit operation conditions considering hydro-turbine nonlinearity

Lu,

2024

J. Phys.: Conf. Ser.

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This paper aims to study the law that the stability of hydropower systems changes with the system operating point and clarify the impact of hydro-turbine nonlinearity and hydraulic nonlinearity on the system stability. Firstly, the piecewise linearized model of the hydro-turbine regulation system (HTRS) at various operating points is established. Then, the HTRS stability domain is calculated and analyzed under various working heads and guide vane openings, and the impact of head variation on system stability is researched from the perspectives of discharge and power. Finally, the stability of various operating conditions under ideal hydro-turbine conditions and rated hydraulic parameter conditions are and compared to clarify the role of the water system and turbine nonlinearity on the stability. The results show that hydro-turbine nonlinearity helps to improve the system stability of the overall operating conditions, but the stability of the HTRS is relatively weak during high-load and low-head operations. Moreover, the hydro-turbine nonlinearity plays a dominant role in the process of stability changing with the operating head. This paper provides a comprehensive analysis of the system stability at different operating points, which can help guide the control optimization of hydropower systems.

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“…These formulas considering both the nonlinearity of the head loss of the diversion tunnel and the steady output of the turbine can be expressed as an amplification coefficient multiplied by the Thoma criterion and have higher precision. Based on the coupling effects of the system and the physical meaning of the superimposed magnitude, Yang [23] derived a new formular of critical stable cross-sectional areas of STs considering the turbine characteristics and layouts of hydropower plants. The above studies demonstrate that considerable progress has been made in research on the operational stability of STs and numerous stability criteria of STs that consider various influencing factors have emerged.…”

Section: Introductionmentioning

confidence: 99%

Stability Criterion for Mass Oscillation in the Surge Tank of a Hydropower Station Considering Velocity Head and Throttle Loss

et al. 2021

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Surge tanks (STs) are important facilities for ensuring the safety of hydropower stations. Reducing the ST size under the premise of ensuring stable mass oscillations within the ST is the main issue. First, according to the basic equations of the mass oscillation for a hydropower station with an ST, a novel expression of the critical stability section of an ST is deduced considering the velocity head and throttle loss. Then, the sensitivity of each influencing factor of the proposed stability criterion is analyzed. Ultimately, through the simulation of small oscillation transients in two case studies, the water level oscillations (WLOs) in an ST based on three stability criteria are compared. The results show that a 20% smaller ST in a hydropower station may result in 10.4% larger oscillations and a 60% smaller ST in a pumped storage power station may result in 14.3% larger oscillations. Compared with the Thoma criterion and the Chinese specification criterion, the stability criterion proposed in this paper can safely reduce the size of the ST since it considers the influence of the velocity head and throttle loss. The proposed stability criterion can provide an important reference for the optimal design of the STs.

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Critical stable cross-sectional area of surge tank in hydropower plant with multiple units sharing common hydraulic system

Cited by 11 publications

References 33 publications

Forced vibration analysis model for pumped storage power station based on the 1D–3D coupling and pipe walls vibration

Forced vibration analysis model for pumped storage power station based on the 1D–3D coupling and pipe walls vibration

Stability analysis of hydropower unit operation conditions considering hydro-turbine nonlinearity

Stability Criterion for Mass Oscillation in the Surge Tank of a Hydropower Station Considering Velocity Head and Throttle Loss

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