The interaction effect of hydraulic transient conditions of two parallel pump-turbine units in a pumped-storage power plant with considering “S-shaped” instability region: Numerical simulation

Rezghi, Ali; Riasi, Alireza

doi:10.1016/j.renene.2017.11.067

Cited by 30 publications

(10 citation statements)

References 18 publications

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“…Furthermore, the complexity of electrical connections is characterized by the power balance and complex vibration zones. Meanwhile, load demand changes for a HPMTT are a key source of system instability and pose operational difficulties associated with hydraulic transient processes such as the emergency startup/shutdown of units [4]. During the emergency startup/shutdown of turbines in generating mode, the operation may frequently startup or shutdown units, which increases the total water consumption.…”

Section: Hydraulic and Electrical Connections Of Hpmttmentioning

confidence: 99%

“…The mainstream has a natural drop of 3830 m, and a development scheme of 21 cascade reservoirs has been planned along the mainstream, which have a total capacity of 30 GW and place the river in third place among China's 13 major hydropower bases in terms of installed capacity [3]. Simultaneously, a series of hydropower plants with multiple turbines in one tunnel [4] have been developed and are in development in southwestern China due to the influence of the geological environment, exploits, and economic conditions. Hydropower plant with multiple turbines in one tunnel (HPMTT) can be interpreted as multi-hydroturbine sets sharing a common penstock [5].…”

Section: Introductionmentioning

confidence: 99%

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Short-Term Load Dispatching Method for a Diversion Hydropower Plant with Multiple Turbines in One Tunnel Using a Two-Stage Model

Liao

Zhao

et al. 2019

Energies

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Short-term load dispatching (STLD) for a hydropower plant with multiple turbines in one tunnel (HPMTT) refers to determining when to startup or shutdown the units of different tunnels and scheduling the online units of each tunnel to obtain optimal load dispatch while simultaneously meeting the hydraulic and electric system constraints. Modeling and solving the STLD for a HPMTT is extremely difficult due to mutual interference between units and complications of the hydraulic head calculation. Considering the complexity of the hydraulic connections between multiple power units in one tunnel, a two-phase decomposition approach for subproblems of unit-commit (UC) and optimal load dispatch (OLD) is described and a two-stage model (TSM) is adopted in this paper. In the first stage, an on/off model for the units considering duration constraints is established, and the on/off status of the units and tunnels is determined using a heuristic searching method and a progressive optimal algorithm. In the second stage, a load distribution model is established and solved using dynamic programming for optimal load distribution under the premise of the on/off status of the tunnel and units in the first stage. The proposed method is verified using the load distribution problem for the Tianshengqiao-II reservoir (TSQII) in dry season under different typical load rates. The results meet the practical operation requirements and demonstrate the practicability of the proposed method.

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Section: Hydraulic and Electrical Connections Of Hpmttmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Short-Term Load Dispatching Method for a Diversion Hydropower Plant with Multiple Turbines in One Tunnel Using a Two-Stage Model

Liao

Zhao

et al. 2019

Energies

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“…The closing law can reduce the maximum pressure in spiral case and the maximum speed of runner and increase the minimum pressure in draft tube during transition [7]. Rezghi et al carried out a numerical simulation on the interaction effect of two parallel units in the instability zone under the condition of conventional load rejection in a unit pumped storage power station with one-tube, two-unit [8]. Yu et al established a mathematical model of hydropower station with multiple turbines sharing a hydraulic system, and studied the output change and dynamic characteristics of the turbine under the action of hydraulic disturbance [9].…”

Section: Introductionmentioning

confidence: 99%

Transient Simulation for a Pumped Storage Power Plant Considering Pressure Pulsation Based on Field Test

Zhang

et al. 2019

Energies

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In this study, fast Fourier transform and inverse transform are adopted for noise reduction filtering the data of load rejection pressure of a single unit in a one-tube, four-unit pumped storage power station. Five-spot triple smoothing method is used to extract the time-average and pulsation value of the water hammer pressure of the spiral case and draft tube inlet. The reasonable correction formula is put forward, and the pulsating pressure rise rate of the spiral case (4.44%) and the draft tube inlet (−1.22%) are obtained. A mathematical model is also established for the transition process of the water conveyance and power generation system of the pumped storage power station, and the field single-unit load rejection condition is simulated. The simulation results are consistent with the measurements, and the accuracy of the calculation model in predicting the time-average pressure of water hammer is verified. Thus, the extreme successive load rejection conditions can be simulated based on the proposed model. Combining with the pulsating pressure rise rate of unit, the actual extreme value of extreme working condition is reasonably calculated. The conclusion shows that the pressure of spiral case and draft tube inlet after considering pressure pulsation can meet the control requirements, avoid the damage caused by extreme working condition test to unit, and ensure the operation safety of unit.

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“…Renewables are responsible for almost 45% of the world's increase in electricity generation in 2018, and they now account for 25% of the world's power demand [3]. By technology, hydropower covers about 85% of the renewable energy power generation for its affordable, renewable, and flexible superiority [4]. Compared to other…”

Section: Introductionmentioning

confidence: 99%

Development and Numerical Performance Analysis of a Pump Directly Driven by a Hydrokinetic Turbine

et al. 2019

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Marine and hydrokinetics (MHK) represent an emerging industry with hundreds of potentially viable technologies, such as potential extractable energy from plain area rivers where the water level differences are very small and the traditional water turbine pump (WTP) cannot be used. A suitable WTP, composed of a tubular turbine directly driving a centrifugal pump, was designed and developed based on computational fluid dynamics (CFD) and model tests. Two general design schemes of such river-current (RC)-driven WTP are presented here, obtaining the desired operating parameters of discharge and pump head. A CFD analysis of Scheme B, which employs a radial outlet, allowing additional degrees of freedom for the dimensions of the centrifugal pump, was carried out and verified experimentally by model tests. The minimum deviation of pump head is within ±5%, and the trend of other working conditions is consistent, so the results of the numerical simulation and model tests show good agreement, demonstrating the feasibility of the CFD method for practical applications. Then, using the CFD method, the optimum rotational speed for the turbine was determined, and the turbine draft tube was improved further. With a turbine runner diameter of 0.5 m, the results show best performance at n = 350 r/min. The straight conical draft tube was changed to an elbow draft tube with multiple exits. Additionally, four different cross-sectional shapes were designed for the pump volute, and their effects on the performance of the WTP were analyzed. Finally, the round shape was selected, because of its best performance. The turbine unit has the highest efficiency of 81.2%, at an inlet velocity v = 2.4 m/s, while the pump exhibits the best efficiency of 90.2% at the design discharge and head of 30 l/s and 4.45 m respectively. Overall, the RC-driven WTP makes good use of the kinetic energy of the river current as a power source, solving the inapplicability of traditional WTP in plain areas.

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The interaction effect of hydraulic transient conditions of two parallel pump-turbine units in a pumped-storage power plant with considering “S-shaped” instability region: Numerical simulation

Cited by 30 publications

References 18 publications

Short-Term Load Dispatching Method for a Diversion Hydropower Plant with Multiple Turbines in One Tunnel Using a Two-Stage Model

Short-Term Load Dispatching Method for a Diversion Hydropower Plant with Multiple Turbines in One Tunnel Using a Two-Stage Model

Transient Simulation for a Pumped Storage Power Plant Considering Pressure Pulsation Based on Field Test

Development and Numerical Performance Analysis of a Pump Directly Driven by a Hydrokinetic Turbine

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