Mechanism and quantified criteria of stability characteristics of hydropower plants with surge tanks during regulation

Yu, Xiaodong; Yang, Xiuwei; Liu, Zhe; Zhang, Jian

doi:10.1016/j.ijepes.2020.106160

Cited by 15 publications

(5 citation statements)

References 25 publications

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“…Parameter Q 3 denotes the tailrace tunnel discharge. For modeling of a HPUDSC, the following three assumptions are mainly adopted [27]: (1) The water column is rigid and incompressible.…”

Section: Mathematical Modelmentioning

confidence: 99%

Operational Stability of Hydropower Plant with Upstream and Downstream Surge Chambers during Small Load Disturbance

Liu

Guo

et al. 2023

Energies

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A surge chamber is a common pressure reduction facility in a hydropower plant. Owing to large flow inertia in the upstream headrace tunnel and downstream tailrace tunnel, a hydropower plant with upstream and downstream surge chambers (HPUDSC) was adopted. This paper aimed to investigate the operational stability and nonlinear dynamic behavior of a HPUDSC. Firstly, a nonlinear dynamic model of the HPUDSC system was built. Subsequently, the operational stability and nonlinear dynamic behavior of the HPUDSC system were studied based on Hopf bifurcation theory and numerical simulation. Finally, the influencing factors of stability of the HPUDSC system were investigated. The results indicated the nonlinear HPUDSC system occurred at subcritical Hopf bifurcation, and the stability domain was located above the bifurcation curve, which provided a basis for the tuning of the governor parameters during operation. The dominant factors of stability and dynamic behavior of the HPUDSC system were flow inertia and head loss of the headrace tunnel and the area of the upstream surge chamber. Either increasing the head loss of the headrace tunnel and area of the upstream surge chamber or decreasing the flow inertia of the headrace tunnel could improve the operational stability of the HPUDSC. The proposed conclusions are of crucial engineering value for the stable operation of a HPUDSC.

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“…Parameter Q 3 denotes the tailrace tunnel discharge. For modeling of a HPUDSC, the following three assumptions are mainly adopted [27]: (1) The water column is rigid and incompressible.…”

Section: Mathematical Modelmentioning

confidence: 99%

Operational Stability of Hydropower Plant with Upstream and Downstream Surge Chambers during Small Load Disturbance

Liu

Guo

et al. 2023

Energies

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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 :…”

Section: D Mocmentioning

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 :

{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%

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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“…Assuming that the water in both the tunnel and the ST is incompressible and rigid, the continuity of the water can be given as [24][25][26]…”

Section: Continuity Equationmentioning

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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Mechanism and quantified criteria of stability characteristics of hydropower plants with surge tanks during regulation

Cited by 15 publications

References 25 publications

Operational Stability of Hydropower Plant with Upstream and Downstream Surge Chambers during Small Load Disturbance

Operational Stability of Hydropower Plant with Upstream and Downstream Surge Chambers during Small Load Disturbance

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

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

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