Surrogate based optimisation of a pump mode startup sequence for a contra-rotating pump-turbine using a genetic algorithm and computational fluid dynamics

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Bibliographic Details
Title: Surrogate based optimisation of a pump mode startup sequence for a contra-rotating pump-turbine using a genetic algorithm and computational fluid dynamics
Authors: Fahlbeck, Jonathan, 1992, Nilsson, Håkan, 1971, Salehi, Saeed, 1987
Source: Augmenting grid stability through Low-head Pumped Hydro Energy Utilization & Storage (ALPHEUS) Journal of Energy Storage. 62
Subject Terms: Surrogate based optimisation, Computational fluid dynamics, Pumped hydro storage, Optimising transient, Startup operation, Gaussian-process
Description: Contra-rotating pump-turbines (CRPT) have been proposed as a new solution for pumped hydro storage (PHS) at low-head sites. The two individually operated runners give both flexibility and complexity during transient operation, such as startup. This paper presents an optimisation approach for the pump mode startup sequence of a CRPT. The aim is to minimise the loads during fast startups and thus extend the lifetime and increase the flexibility of the CRPT. The startup sequence is decomposed into five design variables which determine a valve opening and the speedup of each runner rotational speed. The optimisation procedure includes transient computational fluid dynamics (CFD) simulations and global surrogate-based optimisation (SBO). An objective function, based on an integration of the time derivative of the axial force, is derived and transformed into a Gaussian-process surrogate model. The results show that the SBO can predict an optimal combination of the five variables that limits unfavourable load variations during the pump mode startup sequence. For an optimal startup sequence, the valve should be opened up during 73% of the sequence, the upstream runner should speed up during most of the sequence, and the downstream runner should speed up during the final third of the sequence. The outcome of this work is beneficial for a safe startup operation of possible future PHS with CRPTs.
File Description: electronic
Access URL: https://research.chalmers.se/publication/534686
https://research.chalmers.se/publication/534780
https://research.chalmers.se/publication/534780/file/534780_Fulltext.pdf
Database: SwePub
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