Optimization of Guide Vane Closing Schemes of Pumped Storage Hydro Unit Using an Enhanced Multi-Objective Gravitational Search Algorithm

Abstract

Abstract：The optimization of guide vane closing schemes (OGVCS) of pumped storage hydro unit (PSHU) is the research field of cooperative control and optimal operation of pumped storage, wind power and solar power generation. This paper presents a OGVCS model of PSHU considering the rise rate of the unit rotational speed and the specific node pressure of each hydraulic unit, as well as various complicated hydraulic and mechanical constraints. OGVCS model is formulated as a multi-objective optimization problem to optimize conflictive objectives, i.e., unit rotational speed and water hammer pressure criteria. In order to realize the efficient solution of the OGVCS model, an enhanced multi-objective bacterial-foraging chemotaxis gravitational search algorithm (EMOBCGSA) is proposed to solve this problem, which adopts population reconstruction, adaptive selection chemotaxis operator of local searching strategy and Elite archive set to efficiently solve the multi-objective problem. Especially, novel constraints-handling strategy with eliminating and local search based on violation ranking is used to balance various hydraulic and mechanical constraints. Finally, simulation cases of complex extreme operating conditions (i.e., load rejection and pump outage) of 'single tube-double units' type PSHU system are conducted to verify the feasibility and effectiveness of the proposed EMOBCGSA in solving OGVCS problem. The simulation results indicate that the proposed EMOBCGSA can provide lower rise rate of the unit rotational speed and smaller water hammer pressure than other method established recently while considering various complex constraints in OGVCS problem.Keyword: pumped storage hydro unit; guide vane closing schemes; multi-objective optimization; enhanced multi-objective bacterial-foraging chemotaxis gravitational search algorithm (EMOBCGSA); hydraulic and mechanical constraints

Coordinated Multi-Objective Optimization for Multiple Trade-Offs in Pumped Outage Condition of Pumped Storage System

“…The individuals who can not meet the constraints (14)-(16) should be reinitialized until those constraints are met. The post-processing strategy with elimination and local search based on violation ranking [26] is applied in handling constraints (10)-(13) from pipeline system and pump-turbine. As shown in Fig.7, the specific steps of post-processing method are as follows:…”

“…. , N r , and the fitness can also be calculated by referring to [26]. The non-dominant individuals join the initial elite archive set.…”

“…Step 3.3: Calculate the initial weight and the max eigenvalue of each judgment matrix using (26) Step 3.4: Consistency checking. The consistency ratio CR can be solved by (27).…”

“…Fu et.al conducted the improved hybrid grey wolf optimizer -sine cosine algorithm, which possessed good capability for optimal parameters searching and fast convergence [22], [23]. Various conditions such as turbine start up [24], [25], load rejection [26], load frequency control [27] have been studied using multi-objective algorithms. However, the multiple trade-offs are not adequately coordinated in these studies.…”

Analysis on Guide Vane Closure Schemes of High‐Head Pumped Storage Unit during Pump Outage Condition

“…A conventional method to deal with the transient conditions of the pumped storage unit has been to optimize the GVCS. For instance, a nonoptimal GVCS under extreme conditions causes the WHP and RSRR to rise and exceed the allowable range of design, thus resulting in unfavorable phenomena such as overspeed of the unit, abnormal vibration, and asynchronization of the movable guide vanes [13,14]. is would be a serious threat to the safety of the PSPS especially when it is under the pump outage condition, since the RSRR of the unit will increase greatly and lead to the significant change of flow rate, increasing the WHP.…”