Stability analysis of hydro-turbine governing system including surge tanks under interconnected operation during small load disturbance

Yu, Xiaodong; Yang, Xiuwei; Zhang, Jian

doi:10.1016/j.renene.2018.08.100

Cited by 48 publications

(21 citation statements)

References 28 publications

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“…Subtracting the two red critical curves, a possibility distribution under different discharges is shown as the right half part in Figure 13, where the red On the other hand, in long stepped pipeline systems, the entrapped air is undesirable because the two-phase flow is likely to be harmful including local air retention and cavitation [31]. In these situations, the stepped wells can help release the entrapped air and reduce the intensity of the water hammer by cutting long pressured pipelines apart [32][33][34][35][36][37][38][39]. These strategies have to be studied with the goal of preventing submerged horizontal vortices [40].…”

Section: Discussionmentioning

confidence: 99%

Features and Control of Submerged Horizontal Vortex in Stepped Dissipation Wells

Zhang

Shi

Yao

et al. 2020

Water

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Unlike a horizontal intake vortex, a submerged horizontal vortex is not bounded by a free surface. It has an axial air core submerged in a vessel such as a dissipation well. Due to the motion of its bound point (where the vortex ends), the front wall of the dissipation well could be damaged by cavitation. The goals of this study are to (1) summarize general features underlying the formation and collapsing of horizontal vortices in dissipation wells; (2) identify the features of submerged horizontal vortices; and (3) propose potential measures to mitigate cavitation damage. Through scaling down experiments performed in a transparent dissipation well with two optical sensors, various boundary conditions have been carried out to accomplish this investigation. It was found that a wider inlet flow falling with mixed air can facilitate the generation of submerged horizontal vortices. The optimal mappings between the inlet discharge and the water head differential for maintaining the vortices have been summarized. Depending on different applications, two configurations are proposed to mitigate the adverse effects of submerged horizontal vortices.

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Section: Discussionmentioning

confidence: 99%

Features and Control of Submerged Horizontal Vortex in Stepped Dissipation Wells

Zhang

Shi

Yao

et al. 2020

Water

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“…The HTGS is a complicated nonlinear control system with hydraulic-mechanicalelectrical coupling [11][12][13][14][15]. It mainly consists of the hydro-turbine governor, hydro-turbine, water diversion system, generator, and grid load.…”

Section: Mathematical Modelmentioning

confidence: 99%

“…Therefore, many scholars are studying its stability. Yu et al [11] simulated the small load fluctuation process under the isolated and interconnected operation of two hydropower stations and analyzed the stability of the hydro-turbine governing system (HTGS) during a small load disturbance. Xu et al [12] developed a novel model of the HTGS and used it to analyze the dynamic stability of the HTGS during operation, finding that nonlinear turbine characteristics affected the stability of the HTGS under a load disturbance [13].…”

Section: Introductionmentioning

confidence: 99%

Experimental Study on the Optimal Strategy for Power Regulation of Governing System of Hydropower Station

Wang

Zhang

2021

Water

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Active power instability during the power regulation process is a problem that affects the operation security of hydropower stations and the power grid. This paper focuses on the dynamic response to power regulation of a hydro-turbine governor in the power control mode. Firstly, the mathematical model for the hydro-turbine governing system connected to the power grid is established. Then, considering the effect of water hammer and the guide vane operating speed on power oscillation and reverse power regulation, a novel control strategy based on the S-curve acceleration and deceleration control algorithm (S-curve control algorithm) is proposed to improve power regulation. Furthermore, we carried out field tests in a real hydropower station in order to compare the regulation quality of the novel control strategy based on the S-curve control algorithm with the traditional linear control strategy. Finally, the obtained results show that the proposed optimal control strategy for the hydro-turbine governor improves the stability of power regulation by effectively suppressing reverse power regulation and overshoot. This study provides a good solution for the instability of power and reverse power regulation during the regulation process of the hydro-turbine governor in the power control mode.

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“…If N → ∞, the performance index function will be the same as the Lyapunov function of the system. Therefore, the state trajectories for HTGS (3) will asymptotically converge to the set reference under the control law (24).…”

Section: Fgpc Designmentioning

confidence: 99%

“…Besides, hydro-turbine governing system is a coupling, nonminimum phase and complex non-linear system as it is an integral of hydraulic, mechanical and electrical system [22][23][24]. The hysteresis of hydraulic magnifying parts of governor and mechanical inertia of relay will lead to time delay, which will make the control of hydro-turbine governing system more difficult.…”

Section: Introductionmentioning

confidence: 99%

Takagi–Sugeno fuzzy generalised predictive control of a time‐delay non‐linear hydro‐turbine governing system

Tian

Wang

Zhu

et al. 2019

IET Renewable Power Generation

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This study focuses on a fuzzy generalised predictive control (FGPC) method for a time-delay hydro-turbine governing system (HTGS). First, based on the time-delay Takagi-Sugeno fuzzy model, a time-delay HTGS and its fuzzy prediction model are given. Second, with the help of delay fuzzy linearisation and a fourth-order Runge-Kutta algorithm, a transformed controlled auto-regressive integrated moving average model is obtained. Then, a new FGPC scheme for the time-delay HTGS is proposed. Finally, numerical simulations are implemented to verify the validity and superiority of the proposed method. It also provides a reference for the stability control of relevant hydropower station systems.

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Stability analysis of hydro-turbine governing system including surge tanks under interconnected operation during small load disturbance

Cited by 48 publications

References 28 publications

Features and Control of Submerged Horizontal Vortex in Stepped Dissipation Wells

Features and Control of Submerged Horizontal Vortex in Stepped Dissipation Wells

Experimental Study on the Optimal Strategy for Power Regulation of Governing System of Hydropower Station

Takagi–Sugeno fuzzy generalised predictive control of a time‐delay non‐linear hydro‐turbine governing system

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