Multi-Objective Optimization of Back-to-Back Starting for Pumped Storage Plants under Low Water Head Conditions Based on the Refined Model

Pumped storage plants (PSP) must switch frequently between various working conditions. Moreover, PSPs can fall easily into an S-shaped zone under low water head conditions, especially during back-to-back starting (BTBS), which reduces the stability and safety of unit operation. In this paper, a nonlinear PSP model for BTBS is established by combining electrical subsystem with refined hydraulic-mechanical subsystem. The influences hydraulic, mechanical, factors on process are investigated quantitatively. Choosing speed overshoot stable time as optimization objectives, considering variety constraints, multi-objective particle swarm (MOPSO) algorithm introduced to study optimize two typical startup strategies. results show that: (1) parameters hydraulic-mechanical-electrical system have significant impact process, most unfavorable condition corresponds lowest head; (2) control schemes, novel constant excitation voltage strategy proposed based scheme. Compared current or single-objective, considerably improve at least 68.27% 3.22% worst (3) It further verified that problem trapping in region conditions may be avoided obtained optimal give prominence effectiveness maintaining stabilization